ischaemia - richard · pdf filethe distributio onf aganglioni bowec iln populations throughou...
TRANSCRIPT
ISCHAEMIA : A HYPOTHESIS FOR THE GENESIS OF
AGANGLIONIC BOWEL.
Richard Earlam, M.A., F.R.C.S.
ISABELLA FORSHALL ESSAY PRIZE 1968
CONTENTS
Page
Introduction - are achalasia of the oesophagus, Hirschsprung's Idisease and the rare aganglionic megaduodenumsimilar diseases ?
Anatomical distribution 3
Epidemiology 5
Discussion of anatomy and epidemiology 9
Normal nerve supply of the bowel 12
Abnormalities of the nerve supply 16
Abnormalities of the muscle 18
Previous aetiological theories - I general 19
II Chagas* disease 21
III extrinsic nerve lesions 22
IV neural crest lesions 24
Summary of previous aetiological theories - 26suggestion that the lesions are distributed accordingto the arterial blood supply
Experimental ischaemia as a cause of intestinal atresia 26
Temporary Ischaemia 29
Early embryological development of gut 32
Embryology of oesophageal atresia and tracheo-oesophageal fistula 35
Page
Transitional aganglionlc zone between atretic 36and normal bowel
Epidemiology of atresia and stenosis 37
Discusson of epidemiology 42
Muscle and ganglion cell changes in scleroderma 43
Arterial lesions 44
Hypochlorhydria of the stomach in achalasia 45
Summary 4i
Bibliography 49
OBITUARY
habtlla Farshall
Obituaries of any doctors 'Vlillbe considered for pvttifatifnprovided thai ike donors haveworked m ilit UmieiKingdom for a large partofihtrirf<tr?er, Obituaries mustt>? submitted exclusively toihs BMJ and should be up10 ad<Htt 300 UXirds long;they ShOtM be sent withinnxttMttthSf and preferablywuhin three months, of death."Self-written" obituaries are
ISABELLA FORSHALLCHM, FRCS, FRCSED
Isabella Forshall was one of the pioneers whose workdid much to establish paediatric surgery as a recog-nised branch of surgery in the United Kingdom. It isremarkable that she should have done so at a time whenwomen were not expected to achieve distinctions in theprofessions and when the surgical establishment didnot encourage the development of subspecialties.
Isabella's childhood was spent in affluent surround-ings in west Sussex. She was educated privately athome and never went to school. Her education, nodoubt influenced by her mother, who had read classicsat Girton in the 1890s, imbued her with a keenappreciation of art and literature and particularlypoetry. It is perhaps surprising that a young woman ofher time and background should have embarked on acareer in medicine. When asked about the family'sattitudes to her ambition she would say that she hadbeen expected to make the observance of her socialresponsibilities her first priority and, although neverencouraged to think of a career, was never activelydiscouraged.
Isabella was appointed house surgeon at the RoyalLiverpool Children's Hospital in 1929 and later atAlder Hey Children's Hospital and worked at thesehospitals until her retirement in 1965. In 1939, whileretaining her registrar post, she became honorary-assistant surgeon at Birkenhead and Wirral Children'sHospital and Waterloo General Hospital. In 1942 shebecame an honorary surgeon at the Royal LiverpoolChildren's Hospital.
It was not until the end of the war that Isabella wasable to realise her ambitions for paediatric surgery. Shegathered around her a group of young people inpaediamc surgery and in the associated specialties,whom she fired with her own enthusiasm. This resultedin considerable advances in the surgical treatment ofchildren and in the foundation in 1953 of the Liverpoolneonatal surgical centre. During the first six years of itsactivity the mortality of infants with surgically treat-able congenital abnormalities in the Liverpool regionfell from 72% to 24%, and soon afterwards the Ministryof Health published a report on surgery of the newbornthat strongly recommended the establishment ofsimilar units in all regions.
These achievements brought Isabella widespreadrecognition nationally and internationally. In 1958 shebecame the second president of the British Associationof Paediatric Surgeons; the next year she was electedpresident of the paediatric section of the Royal Societyof Medicine. She was president of Liverpool MedicalInstitution in 1963, was elected an honorary member ofthe British Association of Paediatric Surgeons and ofthe British Paediatric Association, and in 1970 wasawarded an honorary degree of master of surgery fromthe University of Liverpool. Despite having such adistinguished career she had no personal ambition andwould give to her associates much more credit thanthey sometimes deserved for joint achievements; shefought only for the better care of children.
Those who enjoyed her friendship quickly learnt ofher warmth, her delightfully mischievous humour, herabhorrence of pomposity, and her concern for all,particularly the deprived. It was this concern thatcaused her to be among the first to embark on the moreenlightened approach to the needs of children inhospital that today is the norm: in her early days
parental visiting was greatly restricted and awarenessof children's emotional needs was totally lacking.
Throughout her busy working life she devoted everyspare moment to her garden, which was always a joy tosee and where she loved to entertain on a summerevening. She was delighted to retire to her belovedSussex.-JR.
Isabella Forshall, formerly senior paediamc surgfon ai RoyalLiverpool and Alder Hey Children's Hospitals, dud 10 Augustage 88. Bom west Sussex; studied medicine at London School ofHospital for Women (MB, BS 1927).
BMJ VOLUME 300 6 JANUARY 1990
INTRODUCTION
Hirschsprung's disease and achaiasia of the oesophagus are similar because
the ganglion cells in Auerbach's plexus are either absent or fewer than normal.
The aetiology of both diseases is unknown but the surgical treatment alleviates
the symptoms satisfactorily. Textbooks of surgery have emphasized that they
are different, because in Hirschsprung's disease the dilated bowel is normal and
the narrow segment has no ganglion cells but, in achaiasia of the oesophagus,
the dilated gut contains few or no ganglion cells. They are the same type of
lesions because the bowel is aganglionic but the gut reacts differently in each
part to this denervation. All agangiionic bowel is dilated except for the narrow
segment"in Hirschsprung's disease and the lower end of the oesophagus in achaiasia.
In megacolon, caused by Chagas" disease, there is a similar loss of ganglion cells
and in those cases of Hirschsprung's disease which persist untreated into adult
life, there is no narrow segment of obstruction (186, 233). This narrowed bowel,
in which no co-ordinated function can occur, is caused by the failure of circular
muscle relaxation after denervation and by the inability of the propulsive power
of the proximal gut to dilate it. The dilatation in achaiasia is inexplicable if
the competence of the gastro-oesophageal function is thought to be due to a flap-
valve or pinch-cock mechanism of the diaphragm rather than a physiological
sphincter (53,59,85). The denervation produced by the lack of ganglion cells
causes a lack of co-ordinated peristalsis in the body of the oesophagus and a failure
of sphincteric relaxation. The physiological sphincter can be forced open by a
column of liquid when the hydrostatic pressure is high but not by a normal
swallow. Dilatation follows the obstruction. The sphincter is normally closed
and the pressure may temporarily but never permanently open it, so that free
reflux can occur from stomach to oesophagus. This type of sphincter does not
exist in the colon or rectum to explain Hirschsprung's disease.
This essay reviews the present knowledge of the diseases and suggests a unifying
hypothesis for the cause of aganglionic bowel. The rare aganglionic megaduodenum
is also discussed so that a spectrum of lesions which include achalasia of the
oesophagus, aganglionic megaduodenum and Hirschsprung's disease can be
considered together. Many unconnected facets of the diseases are clarified
and made understandable by such a hypothesis, which the majority of the evidence
substantiates. However this is no conclusive proof that the ideas are correct and
future experimental work, based on the hypothesis, remains to be done.
ANATOMICAL DISTRIBUTION
The term agemglionic bowel is used in American literature and has the advantage
that achalasia of the oesophagus, aganglionic megaduodenum and Hirschsprutig's
disease can all be discussed under one heading, but it has the disadvantage of a
neologism and is inexact when a few ganglion cells remain.
Sir Arthur Hurst first suggested that achalasia of the oesophagus might be a
peristaltic disorder because of absent ganglion cells (125), but this was first found
by Rake in 1927 (221). The body of the oesophagus is affected more than the
lower end and the gastro-oesophageal junction (280). The ganglion cells at the
lower end may be reduced in number or normal even when the body of the oesophagus
contains no ganglion cells (3, 45, 161). The cardiac end of the stomach in achalasia
may also contain fewer cells (28, 221). A re-examination of the material used by
Cassella (45) in his study at the Mayo Clinic by the author showed this ganglion cell
loss in some of the cases.
In 1933 the first patient with aganglionic megaduodenum was described (138) and
by 1955 the number had increased to 32 (14). Megaduodenum is rare and is
usually said to be caused by compression of the gut by mesenteric vessels but
histological examination is rarely done. There is no sufficient information available
to describe the distribution or the extent of the lesions.
Considerably more information is available in Hirschsprung's disease about the
distribution of aganglionic bowel (9, 37), which was first described by Tittel in
1901 (268) although this is usually ascribed to Dalle Valle (63). In the majority,
a short segment below the pelvic colon is affected but, in a minority, longer
segments of colon are involved. Bodian (26, 27) gives the percentages as 82%
for the "short" segment below the pelvic colon, 17% for the "long" segment
extending above this level and \% involving the small intesiine (27). 55 cases
of total colonic involvement have now been described (254) and 31 cases involving
both the entire colon and the small intestine up to the duodenal jejuna! flexure
are documented (277). A very rare "mid-zonal" variety occurs (27, 109), in
which the aganglionic segment is confined to the pelvic colon but the bowel
above and below is normal.
Most of the gut may lose ganglion cells but aganglionic bowel is most frequent at
both ends of the gastro- intestine I tract. In more extensive cases either end is
affected and the disease process extends inwards either to the stomach from the
oesophagus or to the colon and small intestine from below.
In two types, megaduodenum and the "mid-zonal" Hirschsprung's disease, there
is an intermediate segment without the ends involved.
EPIDEMIOLOGY
The distribution of aganglionic bowel in populations throughout the world enables
individual factors such as race, age, sex or associated diseases to be compared
and apparent differences may suggest aetiologies. In the absence of complete
epidemiological studies, geographical, racial, sexual and environmental factors
can only be incompletely assessed from patients seen in hospital.
The geographical distirubtion must be assessed from the isolated case reports and
most series of surgical patients or those treated by dilatation represent a biased
selection and a minimal incidence because the total population at risk is not
examined accurately.
Willis described the first case of achalasia in 1674 (285), and by 1920 more than
1200 had been described (43). The Mayo Clinic have published two separate
series of 691 (192) and 601 patients (208). The steady increase may be true due
to a rise in the incidence or apparent because of more patients reported. But
the number diagnosed has not increased appreciably because no real advance in
diagnostic techniques have been made since the advent of radiology. The only
epidemiological study of incidence and prevalence comes from the Mayo Clinic,
Rochester, Minnesota, where the prevalence appears to be about I :IOO,000 with
no changes over the last thirty years (79). These figures are based on small numbers
in a small community but are complete.
Only thirty-two patients with agangl ionic megaduodenum have been described,
therefore no epidemiological study has been conducted (14). Those from Brasil
have not been included in this number (219). Far more work has been done on the
epidemiology of Hirschsprung's disease. In London there is an incidence of
between I : 2000 and I : 10,000 newborn children (26) and in Bremen, Germany
I : 12,000 (9). A calculation of the figures from the Neonatal Surgical Unit
In Liverpool, serving a population of three million, with a birth rate of 60,000
per annum, suggest also an incidence of I : 12,000 live births (92, 227).
No figures of prevalence in the population have been given but since the survival
rate after successful treatment in this disease is high, the prevalence of
Hirschsprung's disease must be far higher than achalasia.
Factors of race, geography and species:
Achalasia is well documented in European and North American literature in
Caucasians but it is more rarely described in other cases. In one study there
were twelve Negroes out of 123 patients with achalasia in Chicago (167). In
South Africa only seven cases have been described in Negroes (151) and in
North Africa eight (41, 47). Most of the Negroes affected were adults but one
Negro infant with achalasia has been reported (223). The disease exists in
Indians (5) and Japanese (205). In Europe, achalasia has been reported from
Budapest (28), Coimbra (43), Graz (164), Leipzig (122), Liverpool (228),
London (15, 83), Louvain (273), Lyons (237), Malmo (187), Moscow (271),
Munich (299), Oslo (123), Oxford (6, 22), Wroclaw (145). Achalasia has also
been described in dogs, occurring spontaneously in more than fifty of which the
breed most affected is Alsation (81, 132, 133).
Hirschsprung's disease also shows no specific geographical or racial bias. Since
the original description by Hirschsprung from Denmark (130) it has been described
in most races and cities including Peking (51) and Cairo (98). A series from
South Africa confirmed that it occurred in Whites, Cape-coloured, and Negroes
(102). Megacolon without histological confirmation has occurred in the cat (62)
and in pigs (152) but not in the dog. Histological confirmation is available
in the large series of inbred mice with congenital megacolon described from
Australia (23, 70).
Sex and age factors :
Sex differences in achalasia were not apparent in two series (167, 299), although
in one large adult series males predominated by 327 to 274 (209) and in one group
of children males predominated by 16 to II (213). At St. Thomas Hospital, London,
males predominated over females below the age of fifty but above this age the
ratio was reversed (15). No definite conclusion can be drawn from the sex
incidence because the figures usually given are not adjusted to the age and sex
distirubtions in the general population. The only available epidemiological
study shows a preponderance of females (79).
In Hirschsprung's disease Bodian and Carter showed that boys predominated over
girls by 3.6 : I but that when "short" segment disease was considered alone it was
5 ; I. However in the "long" segment disease there was almost an equal
incidence (26, 27). Age is an important factor in the distribution of aganglionic
lesions. In the oesophagus the usual age presentation is between 45 and 55,
although the onset of symptoms is a decade earlier (208, 209, 212). Approximately
\Q% have symptoms before the age of 14 (191), and the disease exists in the
neonate (228), the first case being described in 1906 (179). The true incidence of
the congenital or infantile type is probably less than 5% of the total. There were
three cases in Liverpool in a ten year period during which 74 adults were
treated (228).
8
In aganglIonic megaduodenum symptoms occur usually between 17 and 74 with
a mean age of 40 (14) and only one case discovered at birth has been described
(138). In Hirschsprung's disease the mafority are diagnosed soon after birth but
occasionally they may present later (186, 198, 233).
The genetical factors involved are difficult to assess. Three families with achalasia
occurring in two siblings have been described (201, 267, 270) and one with three
brothers affected (74), otherwise no familial incidence is noteworthy. In
Hirschsprung's disease numerous siblings and successive generations are recorded
but Bodian and associates in an analysis of over 200 cases could find no simple
hypothesis as to the nature of the genetic factors (26). The association of
Hirschsprung's disease with achalasia has been described in two patients in a large
series (212) but large series of Hirschsprung's disease contain no achalasic
patients (259). No significant associated diseases are described with achalasia
(209) or aganglionic megaduodenum but in 204 patients with the colon affected
there were other malformations in ten, of which three had mongolism (26). Only
this last association seems to be significant but in the literature it has only been
reported in 19 cases (104). A disturbance of bladder function possibly connected
with aganglionic gladder was found in 5% of children with this disease (257) but
a very detailed study of the vesical ganglia has shown normal ganglion cells in the
bladder and not a single case of megaureter in 278 cases (174).
DISCUSSION OF ANATOMY AND EPIDEMIOLOGY
The anatomical distribution of aganglionic bowel obviously affects the intestinal
tract at both ends of which the lower end is more susceptible. When the disease
involves a greater length of bowel it usually affects one end primarily and then
extends inwards. Megaduodenum and the rare "mid-zonal" variety of
Hirschsprung's disease are two exceptions. The anatomical distribution is similar
to that of intestinal atresia where oesophagus and rectum are most frequently
atretic. The cause of the anatomical distribution is not known but the lesions
are distirubted according to the arterial blood supply. The oesophagus is supplied
above by branches from the inferior thyroid artery, below by branches from the
left gastric and inferior phrenic arteries, and in the middle by two to three branches
from the aorta and bronchial arteries (189). When the left gastric artery is
severed to facilitate gastric mobilisation, the lower oesophagus may be severely
devascularised and the anastomosis between the bronchial artery and the inferior
phrenic arteries may be insufficient (245, 258). The inferior phrenic arteries may
be sufficiently large enough to play an important role in collateral circulation (189)
but they themselves arise from the left gastric artery in about 2% of cases in which
case division of the left gastric artery would be more likely to cause necrosis (189).
Whenever the blood supply is poor, such as in arteriosclerosis, abnormal arterial
distirbutions or blockage of one of the main arterial vessels the middle of the
oesophagus is most susceptible to ischaemia (258). The necrotic area will extend
to involve the lower end of the oesophagus and possibly the stomach, if the blood
supply is more severely compromised.
10
The second part of the duodenum is normally well supplied with blood from the
coeliac axis and the superior mesenteric artery through the superior and inferior
pancreatico-duodenal arteries and the anastomosis between them, but is
susceptible if either one or both of the main aortic vessels is obstructed.
The rectum is supplied by the terminal branches of the superior haemorrhoidal.
artery and there is an anastomosis at the lower end with the branches of the internal
iliac artery. If the whole colon and terminal ileum are involved, the distribution
is that of the inferior mesenteric and sigmoid branches. When the lesion extends
to the duodeno-}e}unal flexure, such an area is supplied by the superior and
inferior mesenteric arteries.
It is suggested that the anatomical distirubtion of aganglionic bowel is based on
its blood supply. The bowel affected also has a distribution similar to that of
the atresias. The arterial supply is contained in vascular pedicles, which,
although apparently fixed, were at one stage of intra-uterine life free, mobile
and involved in replacing thegut in its adult position. If they are susceptible to
rotation, it is conceivable that they could be obstructed at this stage.
The epidemiology of the disease was assessed by searching through the reports of
isolated cases and large series of aganglionic bowel. Apart from the epidemiological
studies in achalasia (79) and Hirschsprung's disease (9, 26) showing the true
incidence, the findings represent only a minimal incidence. A case report
indicates the existence of the disease in a population but not its true frequency
unless the disease has been excluded from the whole population at risk.
Hirschsprung's disease is more common than achalasia and has an incidence of
about I : 12,000. Achalasia has an incidence of I : 100000 and occurs in adults
between the ages of 35 and 45. Hirschsprung's disease may very rarely not present
until adult life, but 5% of achalasia patients have symptoms in early childhood.
There is no geographical nor racial limitation to the diseases because they have
been described in most lands and races, and other species than man are affected.
The sex differences in achalasia are not significant, whereas in "short" segment
Hirschsprung's disease the male predomination is real. Bodian suggests that this
may be associated with the advanced development that a female child has,
compared with a male, at birth but this does not help to find the aetiology. There
is no genetical basis for achalasia in humans although there may be in dogs. But
there may be a genetical basis for Hirschsprung's disease, which is supported by
the evidence of numerous siblings and families as well as the inbred strain of
mice. The mechanism of such hereditary factors is not apparent.
Aganglionic bowel has a random distribution and there are no definite causative
factors that can be deduced from the present available epidemiology.
12
NORMAL NERVE SUPPLY OF THE BOWEL
The intestine throughout its whole length is a hollow muscular tube with an
inner circular and an outer longitudinal muscular layer. In the wall of the
gut lies the intrinsic nervous system of Auerbach's intermuscular and Meissner's
submucous plexus. The extrinsic nervous system is the cranial parasympathetic
distributed in the vagus, the pelvic parasympathetic and the sympathetic nervous
system. The vagus motor fibres, originating in the dorsal motor nucleus, are
pre-ganglionic and synapse with the ganglion cells in Auerbach's plexus, which
relay post-ganglionic fibres. The pelvic para-sympathetic fibres have similar
connection with cells in the colon and rectum. The sympathetic fibres have a
ganglion outside the gut and post-ganglionic fibres pass to the gut wall. The
final termination of these sympathetic fibres is unknown. They may either
(I) end on blood vessels, (2) directly innervate smooth muscle cells or
(3) synapse with the ganglion cells. In the latter case the post-ganglionic
fibres belong to the ganglion cells of Auerbach's plexus and a tri-neuronal theory
of distribution for the sympathetic must be postulated (169). In the intestinal
wall, six neuronal plexuses have been described, but Auerbach's and Meissner's
plexuses are the most important (129). Between the layers of muscle lies a
network of nerve fibres at the junction of which lie Auerbach's plexuses. These
consist of about 40 ganglion cells also called enteric neurones (108), interstitial
cells of Cajal, fibroblasts, pre-gangl ionic non-medu Hated para-sympathetic,
post-ganglionic sympathetic fibres, numerous inter-connecting fibres of the
ganglion cells (129), and occasional sensory organs (143, 165, 250).
13
Meissner's plexus is situated in the submucous layer and is not so large. There
is usually no Meissner's plexus in the oesophagus (108, 166, 222, 253) although
one illustration in Cassella's thesis demonstrates it. The author has never seen
it in the oesophagus except for this one illustration. It certainly exists in the
colon and the rectum.
Dogiel (76) described three types of ganglion cells, all recognised by their large
size and nucleus, cytoplasm with dark granules and their processes. Dogiel
Type I is a rnuitipolar cell with short dendrites and has one predominant axone
which may end on muscle, although even electronmicroscopy can not demonstrate
this convincingly. This cell is more common in the rectum and the oesophagus
and is definitely motor in function (165). Dogiel Type II is a sensory cell,
multipolar with long dendrites passing to the mucosa. It exists in the small
intestine with Type I but is not seen in the oesophagus or rectum. Dogiel Type III
is similar to Type II but has large dendrites which do not anastomose. This
subdivision is based on the appearances after silver staining, and the different
types may possibly be artefacts of this method. The interstitial cells of Cajal
are now thought to be fibroblasts on the evidence provided by the electronmicroscope
(226). The majority of the fibres are interganglionic connections of the intrinsic
nervous system and also connect Auerbach's plexus with Meissner's. The
generally accepted view is that Auerbach's plexus is predominantly motor and
Meissner's sensory. The motor fibres to muscle are the processes of Type I
ganglion cells, although an intermediate fibre plexus as well as the interstitial
cells of Cajal was originally suggested as an intermediate station. The
anatomical basis for a local reflex arc definitely exists independent from the
extrinsic nervous system (165, 166, 276) and this has also been demonstrated
14
physiologically (16, 33). Six months after a vagotomy in dogs the oesophagus
may still have an intact local reflex (38, 139, 150).
The extrinsic nerve supply is predominantly parasympathetic with the sympathetic
playing an unknown but relatively unimportant role. The vagus is said to supply
the gut as far as the splenic flexure (105), based on experimental work in cats
and dogs showing degeneration to this level after section of the vagal trunks (24).
Such degeneration has also recently been confirmed (242) but the number of
fibres ending in this region is very small. The distribution of the vagus on the
intestinal wall ends at the pylorus and the route of any further fibres to the colon
must be in the gut wall. The distal part of the gut is supplied by the pelvic
para-sympathetic but the exact distribution is unknown. Evidence shows that
the motor fibres of the vagus may go no further than the pylorus (272) where
their distribution on the outer wall of the gut ends. The evidence from comparative
anatomy in the chick may be pertinent because the vagus supplies the gut to the
pylorus and then the nerve of Remak passing upwards supplies the gut distal to
this point (40, 294, 295). A further fact, not sufficiently emphasized, is that
the vagus is predominantly sensory and not motor (4, 134) and most of the fibres
are non-myelmated (46, 134) with less than \O°/o efferent at the diaphragm (4).
In the cat there are approximately 3000 motor fibres at the diaphragm (4) compared
with 5 million ganglion cells in Auerbach's and 15 million in Meissner's
plexus (239). If the vagal pre-ganglionic fibres end on Auerbach's plexus
distal to the pylorus, the distribution must be very sparse in proportion to the
vast numbers of ganglion cells. More pre-gangl ionic fibres end on the cells of
Auerbach's plexus in the oesophagus and stomach than in the small intestine.
If structure is to be related to function this will explain why the oesophagus and
15
the stomach are the only parts of the gut with a true coordinated peristaltic
wave whereas the small intestine has an intrinsic thythm with a frequency
dependent on the inherent gradient in the gut. There is also evidence that
the ganglion cells decrease in number from the pylorus to the ileo-caecal
region (173).
The motor fibres of the vagus arise in the dorsal motor nucleus of the vagus.
The central connections of the sensory fibres are in the tractus solitarius.
Retrograde degeneration has been demonstrated after peripheral nerve section
in the dorsal motor nucleus of the vagus (19, 97, 194, 260, 292). The striated
muscle of the oesophagus is supplied by fibres from the nucleus ambiguus.
Retrograde degeneration studies have also shown that the caudal part of this
nucleus Is the source of these fibres (97, 261, 171). In the dog these non-
medullated pre-ganglionic fibres do not pass directly to the striated muscle but
relay in the cells of Auerbach's plexus (120). Evidence on this point is not
available in humans but Auerbach's plexus has been seen in the predominantly
striated muscle part of the oesophagus by the author.
Originally the pathological changes described in achalasia and Hirschsprung's
disease were confined to the ganglion cells of Auerbach's plexus. Recently
more detailed pathology of the changes in Auerbach's and Meissner's plexuses,
the extrinsic nerves, their central connections and the muscles has become available.
16
ABNORMALITIES OF THE NERVE SUPPLY
Rake was the first to describe the loss of ganglion cells in achalasia (221) and
in his original description emphasized that the body of the oesophagus was
affected more than the lower end. The abnormality of those remaining was
noted by Botar and Rubanyi in 1965, who remarked that the plexus appeared to
have been previously present but was involved in a progressive destructive process.
The number of nerve fibres also appears to be decreased but the author from his
experience using a modified Bielschowsky staining technique is not able to say
whether this is a loss of the larger extrinsic nerve fibres or the smaller intrinsic
fibres. Cellular infiltration by small mononuclear cells has been noted
(28, 60, 196, 205, 221). Unpublished work by the author can find no correlation
between cellular infiltration and the severity of the disease and the majority of
autopsy cases do not show this infiltration. It is probably not connected with
epithelial ulceration but it may possibly be related to the dilatation or surgical
procedures which precede death. In some cases this infiltration may also extend
into the surrounding muscle, but not to the submucous layer.
In aganglionic megaduodenum there is an absence or decrease in the number of
ganglion cells and a similar small cell infiltration may also be seen. The tissue
spaces representing the original site of Auerbach's plexus, are still evident but
in this type of agangl ionic bowel there is a marked overgrowth of nerve fibres
in contra-distinction to achalasia (14).
In Hirschsprung's disease ganglion cells are usually completely absent but in
achalasia a total loss is rare. This total loss is confined to the narrow segment
17
and then there is a zone of hypoganglionic bowel of varying length. In this
transitional zone the appearance of the cells suggests a progressive progress
(27, 230, 264). The spaces representing the original site of the plexus are
present but filled with numerous nerve fibres (27, 183, 253). In the rarer cases
where the aganglionic bowel extends to the duodeno-jejunal flexure no such
nervous overgrowth is seen (277). A cellular infiltration has been rarely
observed similar to that found in achalasia (36, 264).
In the extrinsic nerve supply the abnormalities discovered have mostly been in
achalasia and almost no work has been done on similar lesions in Hirschsprung's
disease. Reduced numbers of cells in the dorsal motor nucleus of the vagus have
been found in achalasia (45, 46, 156). A similar lesion of the nucleus ambiguus,
the nucleus for the striated muscle of the oesophagus, was also found in human
achalasia (156). The lesions in the vagal nucleus are specific, bilateral and
only of that part of the dorsal motor nucleus that supplies the smooth muscle of
the oesophagus. In achalasia a lesion of the trunk of the vagus was first suggested
a long time ago (126) but no evidence was obtainable by light microscopy
(87, 175, 176). Recently electronmicroscopy shows a definite decrease in the
numbers of fibres and a progressive destruction of both myelinated and unmyelinated
fibres in the trunk of the vagus, although it is not certain whether they are
efferent or afferent (45).
•':
IS
ABNORMALITIES OF THE MUSCLE
Little attention has been paid to the muscle changes in achalasia. The sphincteric
muscle at the lower end of the oesophagus is usually of normal thickness (278)
although a few cases of hypertrophy have been described. The body of the
oesophagus may be normal, thickened or dilated and thin. It is possible that this
represents an early stage and the latter a terminal decompensated stage of the
disease process.
Rake in his original description noticed that some muscle fibres seemed larger than
usual (221). In the author's experience this usually applies only to the striated
muscle. Sclerosis of the smooth muscle is on the other hand commoner (7f 8,
175, 176, 280, 281). It predominantly affects the circular layer of muscle and the
muscularis mucosa (280) but this distribution is not so clear in those cases the author
studied. No evidence is available as to whether the body of the oesophagus or
the lower end are most affected but the sclerosis appears proportional to the ganglion
cell loss.
Electronmicroscopy has shown definite changes which consist of loss of intercellular
bridges, the nexus, alterations of cytoplasmic condensates, changes in the size and
the shape of the cells and intercellular collagen infiltration (45, 46, 119).
Occasional hypertrophy of individual smooth muscle has also been seen under the
electronmicroscope (119).
•I
19
PREVIOUS AETIOLOGICAL THEORIES
General
Many of the older aetiological theories, more frequent in achalasia than
Hirschsprung's disease, are completely untenable with our present knowledge of
physiology and the extent of the pathological lesions but others deserve careful
consideration. Before the discovery of the ganglion cell loss, weakness of the
oesophageal wall (297), compression of the oesophagus by the aorta (117), the
liver (196) or diaphragm (144) were suggested but these ideas have no physiological
basis.
Purton in 1821 described one of the first cases of achalasia and mentioned that the
patient had received a blow on the sternum thirty years previously (218). Trauma
was also considered important in the aetiology at the beginning of this century (103).
The subject was recently reviewed and thought to be significant (243) but the
majority of patients do not have a history of trauma. Many experienced clinicians
are impressed that achalasia patients are mentally abnormal. Two studies show that
the majority have some psychological abnormalities (184, 234). They were passive,
shy, sensitive and lack aggression. Systematic psychotherapy helped in all twelve
patients treated in one series (234). It is impossible to decide whether these
disturbances are the result or the cause of difficulty in swallowing. No such study
has been done on patients with Hirschsprung's disease who have had their symptoms
relieved by a successful operation. Mickulicz suggested that spasm of the sphincter
was the cause of achalasia (190) but oesophageal motility studies show no spasm but
rather a reduced or normal pressure in the zone of elevated pressure at the lower end
of the oesophagus (59, 85). As early as 1888 a failure of the sphincter to relax on
20
swallowing rather than spasm (82, 188) and an abnormality of the coordinating
mechanisms was postulated (232), but this theory had to mature a long time before
it was proved correct by oesophageal pressure recordings (59),
The discovery of the ganglion cell abnormalities made possible a more logical
approach to the aetiology but although this provided an anatomical basis for the
physiological changes. The cause remained unknown. To postulate that dilatation
itself caused the death of ganglion cells (290) does not help unless the cause of the
dilatation is known and is most unlikely to be true in the absence of experimental
evidence and the knowledge that the dilated bowel in Hirschsprung's disease contains
normal ganglion cells.
Bacterial invasion of Auerbach's plexus was proposed (36). A virus was incriminated
(17, 199), Etzel (88) also suggested Vitamin B| deficiency for the numerous cases
seen in Brasil, based on the clinical association with malnutrition. Experimental
work with vitamin B deficiency in other animals although producing motility disturbances,
has not produced achalasia (54). The main argument against the infectious theories
is that although a virus, such as the poliomyelitis virus, can be specific against a
specific type of nerve cell, they do not explain the anatomical distribution in which
only certain parts of the gut are affected. Oesophagitis as an underlying cause of
the bacterial invasion might explain the cellular infiltration at the lower end of the
oesophagus but does not explain why the body is more affected than the lower end.
There is usually no evidence of reflux in achalasia before treatment nor any colitis
in Hirschsprung's disease.
One infective lesion definitely does cause ganglion cell loss, not confined to
any one part, because Chagas1 disease affects the whole gut. At this stage the present
knowledge of this disease and whether it could be responsible for all cases of aganglionic
bowel will be discussed.
21
||. Chugas1 disease.
Chagas himself first suggested the possible connection between the "megas" and
acute Chagas disease which he first described in 1909 (48, 49). Individuals are
inoculated by the faeces of a reduviid bug, which contain trypanosoma Cruzi
parasites, and suffer from the acute phase of Chagas1 disease with a mortality of
lO^o. After the initial infection repeated inoculations take place and the individual
may or may not enter the chronic phase of the disease. Previous infection can be
recognised by a complement fixation test from which the number of people infected
in Brasil is estimated at about four million and in Venezuela one million (160). The
parasite passes into the lymphatics of the gut which are mainly between the muscular
layers. Reproduction occurs through an intermediate stage in a muscle cell, which
subsequently bursts and liberates parasites into the blood stream. Since Auerbach's
plexus is in this region it is liable to injury and the ganglion cells are killed either
by a neurotoxin (159) or an allergic arteritis (66, 206). The subsequent post-gang I ionic
denervation and muscle damage affects mainly the heart and gut (162) but the urogenital
tract, gall bladder and bile ducts may also dilate. The fact that most patients with
megacolon and megaoesophagus had a positive complement fixation test (66, 67, 69,216)
establishes some correlation and the discovery of leishmania stage in megaoesophagus
was additional circumstantial evidence (163). The experiments producing the chronic
form of the disease in mice (207), dogs (207) and monkeys (113) were proof that the
dilated gut could be caused by trypanosomiasis. The ganglion cell loss in Chagas1
disease affects the whole length of bowel indiscriminately but the colon dilated earlier
and more often than the oesophagus or small bowel. Motility studies of the oesophagus
revealed early changes in asymptomatic patients with proven Chagas1 disease, by
complement fixation test, which were more marked when a concomitant megacolon was
present (215). This work indicates that ganglion cell loss in the oesophagus with or
without dilatation may occur without symptoms. If the colon and oesophagus are
22
equally affected by ganglion cell loss, then the cause of decompensation of the
colon with the production of symptoms must be due to an inherent property of the
large bowel. This may be due to the solidity of its contents or the lack of normal
peristalsis and the absence of the effect of gravity. On this evidence many cases
of non-trypanosomal European achalasia may exist without symptoms.
The parasite itself has a wider distribution than South America and has been described
in the southern states of U.S.A. (31, 121, 124, 183, 279). The reduviid bug which
is the important vector, has also been found in the U.S.A. (286, 288). In one series
of children in an endemic area in U.S.A. Chagas1 disease was diagnosed by
complement fixation test in 2.5% but no permanent defects were noted (287).
Ingelfinger has described four possible cases of Chagas1 disease megaoesophagus in
the indigenous inhabitants of the Southern States, of which one also had E.C.G.
changes (89). This is the total extent of Chagas1 disease in the Southern States of
U.S.A., where both the parasite and the reduviid bug exist. There is no evidence
that Chagas1 disease exists in Europe (161) or Asia (131). Therefore infection by
trypanosomiasis is not the cause of agangi ionic bowel in countries outside South America.
HI. Extrinsic nerve lesions.
Numerous theories have been based on lesions of the extrinsic nerves. Since the
sympathetic system either has no effect on motility or increases the tone in the
musculature, only lesions of the parasympathetic have been postulated. These could
either exist in the vagal nucleus or the trunks of both vagi in achalasia or in the
pelvic parasympathetic in Hirschsprung's disease. No such theory has been postulated
for aganglionic megaduodenum.
23
The experimental evidence for such lesions is extensive and has a long history.
In 1839 Reid in Edinburgh produced dilatation of the oesophagus in rabbits and
dogs after section of the vagus and this was repeated by Claude Bernard in 1849.
Dilatation of the oesophagus can be obtained by lesions of the vagus above the
hilum of the lung, but below this level the effect is confined to the area supplied
below the divided nerve (44). Recently destruction of the vagal nucleus in the
medulla of cats and dogs (128, 238) and bilateral supranodal vagotomy in dogs has
produced a dilatation of the whole oesophagus (127). The results have been confused
by species differences and although permanent dilatation can be obtained in dogs
and rabbits it is only temporary in cats and monkeys. This is almost certainly due
to the return of autonomous peristaltic action in the oesophageal smooth muscle of
cats and monkeys whose distribution is the same as the human, whereas the striated
muscle which extends to the lower end of the oesophagus in dogs and rabbits never
recovers (38, 150). Sympathectomy normally has no effect on motility (107) and
after a preliminary vagotomy the return of normal activity caused by a sympathectomy
(149) must be considered part of the normal recovery of function in denervated smooth
muscle. The experimental evidence for extrinsic denervation in the colon and
rectum is not so extensive. Removal of the pelvic parasympathetic supply may cause
a dilated colon but there is usually retention of urine due to the denervated bladder
and the animals do not survive (3, 142). Although dilatation of the oesophagus may
be produced by bilateral vagal lesions at or above the cervical region, the condition
produced has certain important differences from achalasia. First, autonomous
peristalsis in the smooth muscle of the oesophagus returns after vagotomy. Secondly,
when the extrinsic nerves are destroyed, there is no evidence that the ganglion cells
degenerate. Although one study in monkeys has suggested a reduction in ganglion
24
cells in the oesophagus after vagotomy (24), the majority of evidence shows that
transynaptic degeneration of ganglion cells after pre-gangl ionic denervation does
not occur (129, 147, 150, 172, 185, 205, 229, 242, 253, 272, 276). Most of these
workers have concentrated on morphological changes but a recent study by the author
using a new histochemical technique, by which the ganglion cells in large areas of
oesophageal wall could be counted, showed no decrease in ganglion cells after
subhilar vagotomy in dogs. If an extrinsic nerve lesion does not cause degeneration
of the ganglion cells, the lesions found in the extrinsic nerves must be secondary to
the primary damage of the ganglion cells. Retrograde degeneration in the vagal
nucleus have been described experimentally (19, 97, 292). The probability of such
a wide anatomical distribution of a primary lesion is unlikely because it would be
extremely rare for a pathological process to destroy only a part of the dorsal motor
nucleus of the vagus on both sides of the medulla. But if retrograde degeneration
produces these separated lesions, then the primary pathological process is more likely
to be in the gut wall.
IV. Neural crest lesions.
Neural agenesis has been proposed as a cause of aganglionic bowel (93) and another
group of workers with great experience of Hirschsprung's disease have suggested a
lesion of the neural crest (26). They base the idea on the experimental work in the
chick embryo of Yntema and Hammond, who extirpated the vagal neural crest and
adjacent neural fold within the first few days of development (294, 295) and this
work has been repeated in a turtle (293). Complete removal caused the disappearance
of intrinsic ganglia in the lungs, heart, oesophagus, stomach and intestines and the
incomplete removal produced a decrease distally more than in the proximal parts of
25
the intestine. This idea is attractive because the degree of damage to the neural
crest changes the length of aganglionic bowel to explain the "short" and "long"
segments of Hirschsprung's disease. The lesions produced by neural crest extirpation
are widespread, involving heart and lung gangifa, absence of spinal ganglia at the
level of the lesion and a reduction or absence of sympathetic ganglia as well as the
changes mentioned above. No mention of vesical of ureteric ganglion loss was
made in this work but these would be expected. Such a widespread lesion obviously
does not occur clinically. If a lesion of the neural crest were to explain the loss
it would have to be finely localised to the neural crest of both sides and occur
between the 5th and 10th somite stage in the first week of embryonic life. In
Hirschsprung's disease, the area where Auerbach's plexus should be, are very
noticeably filled with neural fibres rather than cells. In a congenital lesion at
such an early stage one would expect no evidence of these spaces and histological
appearances are more compatible with the cells having been present and then
disappearing, than never having developed. Another objection to this theory is that
it can not explain achalasia, because this is probably an acquired disease to the
extent that ganglion cells are often seen degenerating, and a few may remain and
the distribution in this instance would be expected to involve the whole bowel.
A further criticism is that the "zonal" Hirschsprung's disease and aganglionic
megaduodenum are unlikely distributions of a centrally occurring lesion.
26
SUMMARY OF PREVIOUS AETIOLOGICAL THEORIES
It is valuable to summarise the argument at this point. None of the previously
suggested causes fits all the known facts. The theories of neural crest abnormalities
and extrinsic lesions of the para-sympathetic system are best but there is evidence
that they are not true. A hypothesis is needed that will fit the random distribution
of aganglionic bowel on (I) an epidemiological basis (2) the definite anatomical
distribution in accordance with the arterial blood supply and (3) the associated
lesions in the muscle. Lesions other than those occurring locally in the gut wallS^S
are extremely unlikely, because trans-synaptic degeneration does not occur and
the ganglion cells themselves must be primarily affected. Since the arterial"
distribution is an outstanding feature of the disease one is left with the possible
alternative that an arterial lesion producing ischaemia might be the cause.
EXPERIMENTAL ISCHAEMIA AS A CAUSE OF INTESTINAL ATRESIA
Ischaemia of the gut usually causes other lesions and a digression is necessary to
discuss the effects of ischaemia both in the adult gut and at an early stage of
intra-uterine development. Surgeons are familiar with the result of arterial
obstruction in the gut clinically. The gangrene that develops is either due to an
intra-arterial obstruction due to thrombosis, embolus or compression from the outside
usually by strangulation in a hernia, volvulus or intussusseption. This gangrenous
gut may either be removed surgically or perforate but in certain instances it recovers
spontaneously with ensuing stenosis. Over eighty cases of intestinal stenosis after
a strangulated hernia have been described (50). Experimental work in the dog has
27
elucidated the damage done by ischaemia and the time factors involved (153).
It was shown that epithelium regenerated but that the irreversibly damaged muscle
became stenotic. Experimental gangrene in adult dogs produced peritonitis after
perforation, but if the bowel was sterile peritonitis was unlikely. Experimentally,
dead sterile bowel can be absorbed without trace from the abdominal cavity (170)
but the only time when the bowel is sterile is in utero. Barnard, working with
Professor Wangensteen in Minneapolis, operated on pregnant dogs to produce
gangrenous gut in intra-uterine puppies and when the puppy was born fourteen days
later found a stenosis, web or atresia (12, 13). In these experiments the gangrene
was produced by a volvulus of the small intestine. With the proof of the basic
mechanism provided by this experimental work a classification was postulated for
congenital intestinal small bowel lesions depending on the severity of the
ischaemia (181).
1. stenosis
2. Type I atresia-membrane, septum, web or diaphragm.
3. Type II atresia-proximal and distal blind ends connected by aband-1 ike remnant with or without a V-shaped mesenteric defect.
4. Type III atresia-disconnected blind ends with or without aV-shaped mesenteric defect.
This classification of intestinal lesions is not yet universally accepted although it
has appeared in a textbook (284). Previous theories were based on the concept
that the once solid gut failed to recanalise. Tandler stated that the duodenum was
at one stage of development occluded by epithelium (265) and this was applied
indiscriminatelyito the rest of the gut, supportive evidence being cited that the
oesophagus of the logger-head turtle was also obliterated (148). In man this
probably does not occur (146, 197) although one report describes it (182).
As early as 1901, Bretschneider provided very strong circumstantial evidence that
the theory of "failure to recanalise" was untenable, because he found lanugo,
epithelial cells and meconium distal to the atresia and also demonstrated an atretic
area containing these tissues. This has also been confirmed by others (32, 204, 236).
The occlusion must occur later than the fourth week of intra-uterine life when
meconium is first secreted (284) and the gut must have been patent to allow the
passage of meconium and lanugo.
In 1883 Gartner suggested that atresia and stenosis were due to volvulus because
the lesions were common at the extremities of the bowel and most susceptible to
rotation (95). The finding of rotational defects in a significant number of colonic
atresias is circumstantial evidence for this (94). Bland-Button's principle that
congenital obstruction and narrowing are always found at the situation of embryological
events is applicable here (25). Most of the atresias and stenoses are situated where
the gut is most susceptible to volvulus, intussusseption or strangulation in a hernia.
Duodenal atresia may be caused by the rotational mechanism involved in placing
the duodenum on the right side of posterior abdominal wall, and may also be associated
with malrotation (90, 110). The numerous and often multiple small intestinal atresias
are more likely to be caused by obstruction in an umbilical hernia rather than the
main volvulus defect, although a volvulus affecting only the small bowel could exist.
The localised colonic atresias and possibly some of the small intestinal defects may
be caused by intussusseption. The finding of intussusseption with colonic atresia
29
by Parkulainen is additional evidence (21). It must be emphasized that although
Barnard's work shows that the basic mechanism of ischaemia could be a cause of
intestinal atresia this was only applied in the small intestine. The same mechanisms
for the remainder of the gut have not yet been proved experimentally.
TEMPORARY ISCHAEMIA
In atresia the ischaemia must last longer than a critical period after which most of
the tissues are irreversibly damaged. Little attention has been paid to the duration
of ischaemia or whether the volvulus corrected itself. If the volvulus untwists
itself, atresia may result.without any evidence of the accident having occurred.
Stenosis and the various types of atresia probably result from a long period of
ischaemia, but the bowel could be ischaemic for a shorter time without so much
muscle damage, and it is conceivable that nerve cells could be damaged without
the other tissues being affected. Kessler and Linden found that with experimental
ischaemia of the gut 3 1/2 - 4 hours was the critical period during which the neural
tissue was destroyed irreversibly without damaging connective tissue, muscle or
epithelium (153). The original work on temporary ischaemia of the gut was performed
by Cannon and Burket in 1913 (39). They compressed the small intestine of a cat
between glass plates to render it ischaemic for at least three and a half hours and
selectively destroyed ganglion cells. This compression technique has been
successfully applied to the oesophagus (55, 61, 238). Hukuhara developed this
further by perfusing the small intestine through its arterial supply with a non-
oxygenating substance (136, 137) and Okamoto and his associates with the same
method successfully destroyed ganglion cells in the oesophagus (205). They
shortened the time of anoxia to one hour by adding mercuric chloride to the perfusion
fluid. Their procedure is open to severe criticism because it does not assess the
physiological effects of ischaemia alone, the mercuric chloride adds an unknown
factor and almost certainly produces so much tissue damage that a stricture at
the lower end of the oesophagus is formed, as demonstrated by one of their illustrations.
A recent attempt to produce ischaemia of the oesophagus by a similar method
without mercuric chloride was made in fifteen dogs by the author (80). In these
experiments the lower end of the oesophagus was freed so that the left gastric artery
provided its sole arterial supply. After washing out the blood the area was left
ischaem'c for at least four hours and then the normal anatomy was reconstituted.
Early motility changes in the muscular coordination of the oesophagus were noted
but within nine months they returned to normal and there was no evidence of any
stricture. Morphological ganglion cell changes and a reduction in their number
were found. This series of experiments failed to produce a permanently dilated
oesophagus possibly because only the lower ten centimetres of the oesophagus were
made Sschgemic and the ganglion cell loss was only about 50% of the normal number.
It has been suggested by Koberle with his experience in Chagas1 disease that at
least 90% of the ganglion cells must be absent before incoordination of the
oesophagus leads to dilatation (161, 162). These experiments succeeded in showing
that the basic mechanism of the selective destruction of ganglion cells by temporary
ischaemia was possible. Other recent experiments with anoxia have selectively
destroyed ganglion cells without muscle damage in the small and large intestine
(137, 200, 262, 263) although one attempt has been unsuccessful in the colon of
the dog (73).
This temporary ischaemia is based on the concept that of the four basic tissues
in the intestinal wall-connective tissue, epithelium, muscle and nerve - the latter
is most sensitive to anoxia (75) and no regeneration of any remaining ganglion cells
is possible. Epithelial tissue is most easily damaged but regenerates (35), muscle
31
is also dmaged but shows very little change by light microscopy. No
electronmicroscopic change in smooth muscle or skeletal muscle are available
but evidence in cardiac muscle after ischaemia shows a striking increase in the
amount of intercellular separation (34). The ganglion cells themselves may be
irreversibly damaged and show cytological changes in the early phases after
ischaemia but may possibly take up to six months to disappear (80). Mitoses are
not seen in mature ganglion cells so hyperplasia is presumed not to occur. The
presence of a double nucleolus in the nucleus of a damaged ganglion cell is most
likely the result of the damage and does not indicate regeneration. Although this
evidence suggests that regeneration of neural tissue can not occur, ganglion cells
• can be grown under special conditions in tissue culture and an increase of cells has
been alleged in congenital pyloric stenosis (18), regional enteritis (65), above
stenosing jefunitis (114) and ulcerative colitis (255). If this hyperplasia occurs,
it is at the moment inexplicable and is the only known example of neural cells in
any part of the body undergoing compensatory hyperplasia. In the absence of any
positive evidence to the contrary it must be presumed that once the majority of
the ganglion cells are destroyed there is no regeneration of the remainder.
Experimental destruction of ganglion cells has also been achieved by placing
animals in a hypobaric pressure chamber representing an altitude of 4000 metres
(240) and by the use of carbon dioxide snow which causes vasoconstriction and
anoxia (7, 8). The damage produced by the cold from carbon dioxide snow is
not completely specific and the author thinks that strictures of the lower end of the
oesophagus were probably caused in this work, but the ganglion cells were
successfully destroyed. Sclerosis of the muscle such as seen in some human cases
of achalasia were produced. Alnor was the first to suggest that a localised
disturbance of circulation, producing ischaemia, might be the cause ofeanglion
cell loss (8).
32
There now appears to be sufficient experimental evidence that ischaemia of
approximately four hours duration can produce ganglion cell loss without destroying
other tissues. Obviously if the ischaemia lasts longer than four hours there is a
greater chance that all the ganglion cells will be destroyed, but some muscle
damage may occur (153). As long as the muscle damage is minimal no scarring
and no contraction will occur, but as soon as it is severe enough stenosis will
result. As atresia is probably caused by intra-uterine accidents of volvulus,
intussusseption or strangulation, it seems logical that aganglionic bowel could
occur in the same way. A review of the present knowledge of the embryology
is essential as the next step in this discussion so that the stage of development of
the gut in relation to intra-uterine vascular accidents is accurately known.
EARLY EMBRYOLOGICAL DEVELOPMENT OF THE GUT
The following paragraphs contain a discussion on the development of the individual
components of the intestinal wall, the development of the oesophagus and the
rotation that the gut undergoes in utero before it assumes its final adult configuration,
Smooth muscle layers in the intestine are present by 33-35 days (154). In striated
muscle, development can occur without innervation (2) and there is also evidence
that this can occur in smooth muscle (272). In humans the growth of smooth muscle
has not been as well studied as skeletal muscle but since the upper end of the
oesophagus contains skeletal muscle this may be pertinent. At seven weeks the
first individual skeletal muscle is differentiated, at ten weeks small identifiable
cells are recognised, by sixteen weeks there is no more splitting and striations
33
are present. In the second half of intra-uterine life there is an increase in the
size but not the number of muscle cells. Somatic nerves are seen in the connective
tissue at 10 weeks and make contact with the muscle at eleven weeks, with the
subsequent development of motor nerve endings at 12-24 weeks. Muscle spindles
are seen by eleven weeks and all essential elements are present by fourteen weeks.
By twelve weeks there is sufficient anatomical organisation for the earliest human
embryo reflexes to be present.
There is not so much evidence about neural tissue in the human as in the chick,
but the vagus is well formed by 30 days (256) and the myenteric plexus by the
38th day (154). The ganglion cells are in fact present at an earlier stage and
myelinated fibres have been reported in the intermuscular plexus by the 18th day
(249), but at this stage are usually only represented by Dogiel Type I (165).
In the chick embryo details about the development of neural innervation are
available In great detail but obviously the time factors cannot be indiscriminately
applied to humans. At 86 hours in the chick the visceral branch of the vagus is
present and by 125 hours the vagus reaches the pylorus where it stops ; by the 4th day
the sympathetic also has visceral fibres (272). If the extrinsic nerves are normal
the ganglion cells develop pari passu with the growth of the parasympathetic
from both ends (40, 272). If the vagus is divided in the chick before the ganglion
cells are seen the cells of Auerbach's plexus still develop (40, 68, 272).
|n spite of much work on whether the ganglion cells of Auerbach's plexus arise
from mesoblasts (272) parasympathetic neuroblasts (202, 294) or sympathetic
neuroblasts, the probability is that they arise from the parasympathetic nervous system.
34
Blood vessels are found entering the human embryo intestinal wall by the 37th
day (153) and definite adult type blood vessels develop later.
The development of the intestinal epithelium is controversial. In the oesophagus
the majority of the opinion is that the lumen is never occluded (146, 154) although
in the logger-head turtle an epithelial plug was found (148). The duodenum seems
more likely to be obstructed by a relative overgrowth of epithelium (265). The
rectum and colon are very rarely affected by this process in the human (182).
The development of the thorax and the descent of the diaphragm is important in
relation to the oesophagus. On the 33rd day the diaphragm is attached to the
caudal end of the infrahyoid mass and by the 34th day it is disconnected and
descending (154). This descent is caused by differential growth in which the
oesophagus markedly elongates. There is disagreement as to when the diaphragm
has fully descended. Keibel and Mall say at 36 days, but it may be later.
Between the 5th and IOth week the gut enlarges in length to such an extent that
there is not room in the abdominal cavity and it prolapses through a large umbilical
hernia. At the 5th week there is only a single loop but with the vast increase of
length the loops become more complex. Towards the 10th week the gut begins to
return, undergoing a 270 degree anti-clockwise rotation, so that the duodenum
reenters the abdomen first and the caecum abruptly and finally at the 10th week
(10, 77, 116). This anti-clockwise rotation is still evident in the adult by the
position of the bowel, the taeniae coli of the colon, the anti-clockwise spiralling
of the longitudinal muscle of the small intestine (42) and the oesophagus (252) and
the rotation of the vagi on the oesophageal wall.
35
A volvulus is most likely to occur when the gut is prolapsed through the umbilical
hernia between the 5th and 10th week of intra-uterine development. Since the
rotational effects of the gut are more evident towards the end of this period the
chances of volvulus occurring then are greater than in the 5th to 7th week.
It is probable that a volvulus results from excessive rotation between the 7th and
10th week. By the 7th week the intestinal wall has most of its essential components.
The smooth muscle cells are present but still dividing. Auerbach's plexus and
the extrinsic nerve supply are in situ. If four hours of ischaemia occurred at
this stage the nerve cells would be destroyed and any muscle damage would be
compensated by hyperplasia of the remainder, because this process normally
persists until the 16th week.
EMBRYOLOGY OF OESOPHAGEAL ATRESIA AND TRACHEO-OESOPHAGEAL FISTULA
The pathology of these early embryonic events has been described in an excellent
contribution on tracheo-oesophageal fistula by Smith (247). This study and that
of Streeter (256) are based on a survey of over a hundred human embryos in the
Carnegie Institute. Smith studied three of the five available early embryos with
oesophageal atresia ( 100, 112, 177, 196, 291). It was concluded that the lesion
occurred at the critical stage when the trachea and oesophagus are separating
before the fifth week of intra-urerine development (256) and emphasized that the
separation was caused by endothelial proliferation on the inside of the common
tracheo-oesophageal tube as with the endocardial cushions, rather than a
constriction from the outside. Tracheo-oesophageal fistula was compared with
urogenital fistula and it was mentioned that atresia of the ventral and secondary
developing system was rare. Lesions of Type I or II in the oesophagus may arise
from a failure of the fistula to persist or develop. Smith found no support for
the epithelial occlusion theory but suggested an abnormality of differential growth
r
36
and insufficient tissue availability. The value of this work lies in localising
the formation of a tracheo-oesophageal fistula to some time before the 33rd day.
Since the trachea and the oesophagus are separated after the 33rd day it would
be unlikely that a developmental error would cause a fistula after this. It is
suggested that those atresias of the oesophagus which are not associated with
fistula must be caused by a developmental error occurring after the fifth week
when the trachea and the oesophagus have already separated.
TRANSITIONAL AGANGLIONIC ZONE BETWEEN ATRETICAND NORMAL BOWEL
Further circumstantial evidence for the connection between atresia and
aganglionic bowel would be provided if they were both described in the same
patient. Indeed if the same aetiology is postulated there should be a zone of
transition between atresia and aganglionic bowel as well as the transition between
aganglionic and normal gut. Parkulainen and his associates have described the
transition of recta! atresia through aganglionic bowel to normal in 15 cases of
rectal atresia (211). This does not occur in every case but is more likely to occur
in Type III. The transitional zone has been reported by others (29, 214, 230)
but denied by Swenson (257), although one case was discovered in a series of
150. From the records of 32 paediatric centres it has been calculated that this
transition occurs in 3.4% of rectal atresia (155). But this percentage increases,
QS Parkulainen demonstrated, if Type III atresias alone are considered (211).
In the oesophagus there is physiological evidence of disturbed motility after the
repair of a tracheo-oesophageal fistula (72, 84, 115, 178, 246). This may be
the effect of the operation but deficient peristalsis has been noted in the distal
blind pouch before the operation (52, 157). This abnormal and deficient
37
peristalsis could be caused by a deficiency of ganglion cells in the body of the
oesophagus. The author studied the material available at the Mayo Clinic
representing unoperated tracheo-oesophageal fistulas and found definite evidence
of reduced ganglion cells in a few cases. This was rare/ and if found, occurred
usually in the distal segment and only for a few mm. It was quite often associated
with muscle damage but no correlation to the type of tracheo-oesophageal fistula
was possible. The explanation of why the lower end of oesophagus and not the
upper end is involved by this loss may be due to the poorer blood supply of the
lower end (18). No striated muscle was found in these cases in the distal segment,
so if an extrinsic nerve lesion were to have been caused during the repair, the
smooth muscle would be expected to resume autonomous control. In some cases
the gastro-oesophageal junction possibly contained reduced numbers of ganglion
cells but no definite conclusion can be drawn with the limitations of the present
technique and in the absence of further studies.
The hypoganglionic segment in Hirschsprung's disease shows a great variation in
length so the aganglionic transitional segment may be expected to show some
variation. There is enough objective evidence that agangl ionic and atretic
bowel can occur in the same patient with a transitional zone. This is not found
in every case and the reason for this is not obvious.
EPIDEMIOLOGY OF ATRESIA AND STENOSIS
It has been emphasized earlier that the anatomical distribution of aganglionic
bowel had certain similarities to that of stenosis and atresia. If the same mechanism
is postulated for these lesions, the incidence of the different types might help in
38»
elucidating some of the aetiological factors. Few epidemiological studies
are available to give a true incidence so the figures from hospital series must
be analysed. Such numbers are more reliable when the majority of the affected
patients are treated in any one centre. American and London figures are
suspect because many children are treated privately or in other hospitals.
Provincial centres such as Liverpool, where a neonatal unit treats almost all the
patients, provide the best available comparative figures (92, 277). Forshall
points out that since 75% of the children in Liverpool and the surroundings are
born in hospital there are relatively few patients lost because of failed diagnosis (92),
Oesophagus.
One epidemiological study assesses that oesophageal atresia in New England
occurs at the rate of I : 5000 or more live births (140). A calculation from the
available Liverpool figures gives a rate of : 4000 (92, 227). The figure of
I ; 800 pregnancies from Bristol is almost certainly biased by selection and is
too high (20). Oesophageal and rectal atresia each account for 30% or more
of the total number of atresias, which means that they are the most common
(92, 94), although the Great Ormond Street Hospital for Sick Children figures
suggest that oesophageal atresia is not so common as rectal atresia (56, 57). The
usual classification of tracheo-oesophageal fistula with oesophageal atresia is
that of Vogt (275) and his original figures, in which 8% are Type III and the
minority have atresia alone, are still basically true. It seems logical to add the
rarer tracheo-oesophageal fistula without atresia to the classification and the
latest figures from Great Ormond Street indicate this group form 5% of the
total (56). In 1966 only 70 of these had been described in children (195) but
they are frequently not diagnosed. The so-called traction divert!culum of the
mid-oesophagus with a fistula, once attributed to the traction of tuberculous glands
39
but whose incidence has not decreased with the reduction in tuberculosis, is
now considered congenital and would be the persistent equivalent of a fistula
without atresia (298). If the adult diverticula are considered to be congenital
then the incidence of tracheo-oesophageal fistula without atresia is probably 5%I m
of the total fistulas with or without fistula. Congenital stenosis of non-peptic
origin has been described in children and adults (106, 115, 244). They usually
consist of incomplete obstruction in the middle one-third or two-thirds extending
2-3 mm. or rarely longer. Girdany has described more than thirty such cases
From Pittsburgh in a ten-year period (99). These figures result from careful work
so the condition must be considerably under-diagnosed. Congenital webs are even
rarer (193) although Guisez was reported having found 5 in 2000 oesophagoscopies
(266). Webs and stenoses have been described together (106, 118, 135) and a
web with achalasia once (235). The prevalence of achalasia is I : 10,000
in the one epiderniologica! study available and the incidence is probably
I • 100,000 (.79).
From these figures it will be seen that atresia of the oesophagus with a fistula
occurs at about I : 5000 live births.
Atresia alone is ten times as rare at I : 50,000. The figures for congenital
stenosis are misleading because the condition is under-diagnosed. Achalasia
is even rare and occurs at about I : 100,000.
Rectum.
Rectal atresia is usually subdivided accordingly to the classification of Ladd (168)
but it has been pointed out that Type IV is colonic atresia and not rectal (94,236)
40r
although this is not universally accepted. No epidemiological study is
available for this condition but it has the same incidence as oesophageal atresia,
occurring at least in I : 5000 births (92, 94, 227). Most of the Type III, which
form the majority, but almost none of Type IV are associated with fistulas.
Stenosis of the rectum is rare, and it is difficult to assess the true incidence from
the literature. The classification of stenoses in the ano-rectal region is not as
simple as in the oesophagus. If Typ« IV is considered colonic then the figures
for colonic atresia and stenosis can be compared. Lesions of the colon are
fifty times rarer than those of the rectum (94) and the colon is more commonly
affected distally than proximally. In the same series there were two zonal
stenoses and three zonal afresias of the colon. Hirschsprung's disease occurs
at about I : 10,000 and the distal colon is far more frequently affected than the
proximal, with zonal aganglionisis at 1-2%.
From these figures no clear pattern arises. But rectal atresia is commoner than
Hirschsprung's disease. Stenotic and atretic lesions similar to the anatomical
distribution of Hirschsprung's disease occur with approximately the same proportional
incidence.
Duodenum.
Duodenal atresia is about half as common as oesophageal or rectal atresia (94)
and occurs in about I : 12,000 live births (92, 227), \5% have other lesions
distally (90). Stenosis is more than twice as rare. More than half are above
the duodenal papilla and the remainder are below (64, 251, 282). Aganglionic
megaduodenum and the distribution is unknown. Atresia is the commonest lesion.
Stenosis is rare and aganglionic megaduodenum is very uncommon.
41
Jejunum and ileum.
Atresia of the jejunum has about the same incidence as duodenal atresia (94).
Stenosis constitutes about one half of all atresias and stenoses in the small
intestine (III). Rarely stenosis may occur in the adult as a late result of
strangulated hernia but only about 80 have been described (50).
Both congenital atresia and stenosis may be multiple. Aganglionic jejunum
and ileum have only been described in Chagas1 disease. In this disease
aganglionic small bowel may exist without symptoms, so it could exist in counteies
outside South America without recognition. Stenosis must be of a small diameter
before symptoms occur, so many may not be diagnosed.
Once again atresia is commoner than stenosis. In the jejunum and ileum the
lesions are multiple and no aganglionic segment has been described.
Stomach.
To complete the spectrum 52 stenoses, webs and atresias have been described in
the stomach (96) and more webs have been recently added (231). Aganglionic
stomach exists in Chagas1 disease and in the fundus of patients with achalasia.
Stenosis, web and atresia are usually in the middle or the antrum of the stomach.
42
DISCUSSION OF EPIDEMIOLOGY
The distribution of stenosis, atresia and aganglionic bowel have all been
considered together because ischaemia may cause all these lesions. The
overall pattern emerges that atresias are more common than stenosis or aganglionic
bowel. If ischaemia, caused by a volvulus, causes all these lesions, there would
be more chance of permanent than temporary damage, which would affect only
the neural elements. Atresia would then be commoner than stenosis or
dganglionosis caused by lesser degress of ischaemia.
Atresia with a fistula must occur earlier in embryonic development than
atresia alone because the structures concerned have separated completely. The
critical stage is approximately in the 4th to 5th week. Although the gut can
be subjected to rotational stresses before separation has occurred, it is more
likely to occur later between the 5th and 10th weeks when the hernia is larger
and the gut undergoes rotation in its return to the abdomen. The mechanism
for the failure of separation in the development of a fistula with atresia at botfi
ends of the gut is unknown, but it could also be associated with a disturbance of
the blood supply. The effects of the volvulus are not due to the mechanical
compression of the gut itself but to the obstruction of the blood supply. When
the left gastric artery and the superior haemorrhoidal artery are obstructed, the
gut situated at the distal end of the distribution of these arteries is most likely
to be ischaemic. The presence of the descending diaphragm does not alter the
effect of obstructed blood supply and is almost complete before the rotational
stresses occur. When the gut is returning to the abdomen the secondary
43
rotation of the duodenum may cause ischaemia, but this is naturally rarer.
The multiple jejuna I and ileal lesions are more likely to occur later when the
majority of the gut has returned to the abdomen and a small umbilical hernia,
in which gut can strangulate, remains. The zonal lesions of the colon are
probably caused by intussusseption and are therefore extremely rare.
The epidemiology of these lesions offers almost no help in the search for other
causes. Although numerous familial incidences have been reported, overall
epidemiological studies comment on the relatively low position of congenital
malformations in the list of diseases with familial tendencies (158, 203). A
familial tendency to malrotation may be feasible, but the cause of this tendency
is still unknown. Allowing for the variations in diagnosis there seems to be no
change of the disease incidence in recent years, which would exclude any
environmental factors such as infection or irradiation. This comparison suggests
that more aganglionic megaduodenum and congenital stenosis of oesophagus should
be diagnosed than at present.
MUSCLE AND GANGLION CELL CHANGES IN SCLERODERMA.
Aganglionic bowel occurs randomly as achalasia or Hirschsprung's disease or with
a definite cause apparent such as Chagas1 disease where destruction of the ganglion
cell is caused by the Trypanosoma Cruzi. The only other disease known at the
moment where ganglion cell damage occurs is scleroderma, which is a generalised
disease of unknown origin. The smooth muscle of the small arteries is most
affected and a Raynaud's phenomenon may exist. Although the most obvious
44
changes occur in the skin, the oesophagus is abnormal (58). Peristalsis is
poor and there is a reduced zone of elevated pressure at the lower end of the
oesophagus. A reexamination of the two cases reported from the Mayo Clinic
(269) by the author showed in one advanced case loss of ganglion cells of the
oesophagus and stomach, and in the other a reduction in the number as well as
the marked muscular damage. This was first described in South Africa by
Goetz (101). Although the neural tissue loss may be secondary to the muscular
damage, it is suggested that the muscular changes and the ganglion cell loss
are secondary to damage of the small arteries and subsequent ischaemia. In
myotonic dystrophy and progressive muscular atrophy, there is patchy necrosis
of the muscles but the ganglion cells are normal or enlarged (217). The motor
abnormalities of the oesophagus in these diseases are due to muscle damage alone.
ARTERIAL LESIONS
Arterial anomalies were noted in some of the embryos examined by Smith with
oesophageal atresia and tracheo-oesophageal fistula (247) and it has been said
that I O^o have vascular anomalies (115). Whether these abnormal blood vessels
affect the blood supply of the oesophagus or not is unknown, but there is a
definite relationship. Damage to the small arteries in achalasia have been
previously noted (36, 175, 196) but damage to the larger arteries such as the
coeliac axis or the left gastric artery may also occur. Coeliac axis compression
has been diagnosed during life in 17 cases (225) and coeliac angina in 15 further
patients (78). In 110 autopsies 44^4 had a narrowed coeliac axis (71). The
older patients with achalasia may have generalised arteriosclerosis or specific
I
45
damage to the blood vessels for the nutrition of the oesophagus. Abnormalities
of oesophageal motility in nonagenarians (248) and reduction in ganglion cells
with increasing old age has been found (160, 175). Although arteriosclerosis
and old age may be concomitant, the connection between arteriosclerosis and
ganglion cell loss is mere supposition at the moment. In one case, who died after
a Heller's operation, a careful study by the author of the coeliac axis and the blood
vessel supply to the oesophagus revealed no abnormality, but the patient was
relatively young. Each main arterial axis of the abdominal aorta and its smaller
branches has its own specific syndrome and it is tempting, but possibly facile, to
suggest that the left gastric artery lesions produce achalasia.
HYPOCHLORHYDRIA OF THE STOMACH INACHAIASIA
There is a definite increased evidence of hypochlorhydria in achalasia (141),
which is a true finding not due to the failure to the stomach tube to pass through
the lower end of the oesophagus. A possible explanation is that this is also a
lesion of the extrinsic vagal nerve supply but it is probably due to aganglionic
stomach that is unable to respond to any nervous stimulation. In Chagas1 disease
aganglionic stomach has been found and hypochlorhydria has been noted in
20% (274) to 70% (86). When the stomach is hypersensitive to mecholyl,
denoting vagal denervation, there is hypochlorhydria in 100% (274). The
connection of this hypochlorhydria with aganglionic stomach, unassociated with
Chagas' disease, has yet to be proved, but it is unlikely to be due to a vagal
lesion because pyloric obstruction does not occur.
46
SUMMARY
It is considered justifiable to assess all aganglionic bowel together so that common
factors, important in aetiology, might emerge. The physiological differences in
the gut explain why the dilated segment of Hirschsprung's disease contains ganglion
cells and the dilated body of the oesophagus has no ganglion cells. A study of
the epidemiology of aganglionic gut reveals that the diseases affect other species,
most races and both sexes with a relatively random distribution, occurring with a
fixed incidence in populations but no definite aetiological factors emerge.
The anatomical distribution of achalasia of the oesophagus, aganglionic
megaduodenum and the various types of Hirschsprung's disease is analysed and
found to be distributed according to its arterial blood supply.
The associated muscular damage, lesions of the vagus and its nuclei are discussed.
It is deduced that the primary lesion must occur in the gut and that the other changes
are secondary. The experimental evidence for the selective destruction of
ganglion cells by four hours of ischaemia is cited and it is suggested that the areas
of aganglionic gut could have their blood supply interrupted for this length of
time. Between the 5th and 10th week of'intra-uterine life the gut undergoes
rotation through 270° before it returns to the abdominal cavity. Temporary
ischaemia at this stage would make either end of the gut ischaemic. Hirschsprung's
disease and the rare infantile achalasia would ensue and the same rotational
effect could affect the duodenum. The various length of bowel affected and the
numbers of ganglion cells lost are proportional to the type and severity of the
ischaemia. Decompensation of such a congenital lesion, if only a proportion of
the cells were destroyed, might occur 20 to 30 years later to explain some of the
cases of achalasia. If the oesophagus and the rectum were equally affected by
47
ganglion cell loss the rectum would decompensate first and dilate, because of
physiological differences partially associated with the solidity of the contents.
But evidence indicates that many cases of achalasia may be caused by ischaemia
occurring later in life when the blood supply is reduced by arterial obstruction
from thrombosis or arteriosclerosis.i'I
The experimental work of Barnard showed that ischaemia from an intra-uterine
volvulus could cause intestinal atresia or stenosis. A common mechanism would
explain the similarity of the anatomical and epidemiological distribution of atresia,
stenosis and aganglionic bowel.
Oesophageal atresia associated with tracheo-oesophageal fistula occurs before
the 5th week of intra-uterine life before the trachea and oesophagus are completely
separated and the associated fistulas of the rectum probably occur at the same time.
It is feasible but less likely that lesions with associated fistulas are associated with
ischaemia and malrotation of the gut. Atresias without associated fistulas must
occur later than the 5th week when the gut is separated from the surrounding
structures.
48
The hypothesis is that temporary ischaemia for approximately four hours can
selectively destroy the ganglion cells of the gut without damaging the other tissues
permanently and cause an aganglionic segment. This may occur in the adult to
explain achalasia when the arterial supply is obstructed by thrombosis or
arteriosclerosis or as a congenital intra-uterine lesion to explain Hirschsprung's
disease. Many cases of achalasia may represent a decompensated intra-uterine
lesion. Depending on the duration of ischaemia, one of five lesions may result ;
1. Aganglionic bowel
2. Stenosis5
3. Type I atresia - septum, web or diaphragm
4. Type II atresia - band-1 ike remnant
5. Type III atresia - disconnected blind end
49
BIBLIOGRAPHY
1. ADAMS, C.W.M., MARPLES, E.A. and TROUNCE, J.R. :Achalasia of the cardia and Hirschsprung's disease.The amount and distribution of cholinesterases.Clin. Sci. 19 :473, I960.
2. ADAMS, R.D., DENNY-BROWN, D. and PEARSON, C.M. :Diseases of Muscle : a study in pathology.Harper, New York, 2nd Ed., 1962.
3. ADAMSON, W.A.D. andAIRD, I. : Megacolon : evidence infavour of a neurogenic origin. Brit. J. Surg. 20 : 220,1932.
4. AGOSTINI, E., CHINNOCK, J.E., de BURGH DALY, M. andMURRAY, J.G. : Functional and histological studies of the vagus
nerve and its branches to the heart, lungs and abdominalviscera of the cat. J. Physiol. 135 : 182, 1957.
5. AHMED, H.U. : Carcinoma oesophagus as a complication of achalasiacardia. Report of a case. Indian J. Surg. 25 : 559, 1964.
6. ALLISON, P.R. : Discussion on treatment of achalasia of the cardia.Proc. Roy. Soc. Med. 43 : 425, 1950.
7. ALNOR, P. : On the pathogenesis of cardiospasm. J. Thorac.Cardiov. Surg. 36: 141, 1958.
8. ALNOR, P. : Die experimented Achalasie des Oesophagus.Thorax-chirurgie. 10 : 254, 1964.
9. ALTHOFF, W. : Zur Genetik der Hirschsprungen Krankheit.Z. Menschl. Vererb. Konstitutions I. 36 : 324, I960.
10. AREY, L.B. : Developmental Anatomy. Sounders, W.B., Philadelphiaand London, 1954.
11. AUERBACH, L. : Fernere vorlaufige Mittheilung uber den NervenapparatdesDarmes. Virchow Arch. Path. Anat. 30:457,1864.
12. BARNARD, C. : The genesis of intestinal atresia. Surg. Forum.7 : 393, 1956.
13. BARNARD, C. : Etiology of congenital intestinal atresia. Thesis,Graduate School, University of Minnesota, 1958.
14. BARNETT, W.O. and WALL, I. : Megaduodenum resulting from theabsence of the parasympathetic ganglion cells in theAuerbach's plexus. Ann. Surg. 141 : 527, 1965.
5O
15. BARRETT, N.R. : Achalasia of the cardia : reflections upon aclinical study of over 100 cases. Brit. Med. J. I : 1135,1964.
16. BAYLISS, W.M. and STARLING, E.H. : The movements and innervationof the small intestine. J. Physiol. 24: 99, 1899.
17. BEATTIE, W.J.H.M. : Achalasia of the cardia with a report of 10 cases.St. Bartholomew's Hosp. J. 64 : 39, 1931.
18. BELDING, H.H. Ill and KERNOHAN, J.W. : A morphologic studyof the myenteric plexus and musculature of the pylorus withspecial reference to the changes in hypertrophic pyloric stenosis.Surg. Gynec. Obstet. 97 : 322, 1953.
19. BELL, F.R. : The localisation within the dorsal motor nucleus ofthe vagus of efferent fibres to the ruminant stomach.J. Anat. 94 : 410, I960.
20. BELSEY, R.H.R. and DONNISON, C.P. : Congenital atresia of theoesophagus. Brit. Med. J. 2 : 324, 1950.
21. BERNARD, C. : Paralyse de I'oesophage par la section des deux nerfspneumogastriques. C. R. Soc. Biol. (Paris). I : 14, 1849.
22. BESANCON, F., JAN IN, B . and DEBRAY, C. : Le mega-oesophage,cardiospasme reactionel. Donnees electromanographiques etcineradio-metriques. Sem. Hop. Paris. 8 : 1555, 1962.
23. BIELSCHOWSKY, M. and SCHOFIELD, G.C. : Studies on megacolonin piebald mice. Aust. J. Exp. Biol. Med.Sci. 40 : 395, 1962.
24. BINDER, H.J., BLOOM, D.L., STERN, H., SOLITAIRE, G.B. etal. :Experimental and clinical observations on the relationshipbetween achalasia and esophageal spasm. Gastroenterology.50 ; 881, 1966.
25. BLAND-SUTTON, J. : Imperforate ileum. Amer. J. Med. Sci. 98 : 457,1889.
26. BODIAN, M. and CARTER, C.O. : A family study of Hirschsprung'sdisease. Ann. Hum. Genet. 26:261,1963.
27. BODIAN, M., CARTER, C.O. and WARD, B.C.H. : Hirschsprung'sdisease, with radiological observations. Lancet. I : 302, 1951.
28. BOTAR, J. and RUBANYI, P. : Beitrage zur Neurohistologie desMegaosophagus. Acta Neuroveg. (Wien). 27 : 348, 1965.
51
29. BRAYTON, D. and MORRIS, W.J. : Further experience with thetreatment of imperforate anus. Surg. Gynec. Obstet.107 : 719, 1958.
30. BRETSCHNEIDER, R. : Beitrag zur congenitalen Dunndarmatresie.Arch. Gynaek. 63 : 209, 1901.
31. BROOKE, M.M., NORMAN, L., ALIA1N, D. and GORMAN, G.W. :Isolation of T. Cruzi-like organisms from wild animals collectedin Georgia. J. Parasit. 43 : 15, 1957.
32. BRYAN, R.C. : Congenital occlusion of the small intestine.Amer. J. Surg. 22 : 297, 1923.
33. BULBRING, E., LIN, R.C.Y. and SCHOFIELD, G. : An investigationof the peristaltic reflex in relation to anatomical observations.Quart. J. Exp. Phys. 43 : 26, 1968.
34. BURDETTE, W.J. and ASHFORD, T.P. : Response of myocardial finestructure to cardiac arrest and hypothermia. Ann. Surg.158 :5I3, 1963.
35. CAMERON, G.R. and KHANNA, S.D. : Regeneration of intestinalvilli after extensive mucosal infarction. J.Path.Bact. 77 : 505, 1959,
36. CAMERON, J.A.M. : Suggested explanation of cardiospasm based onpathological changes. J. Laryng. 43:218,1928.
37. CAMERON, J.A.M. : On the aetiology of HIrschsprung's disease.Arch. Dis. Child. 3 -.210, 1928.
38. CANNON, W.B. : Esophageal peristalsis after bilateral vagotomy.Amer. J. Physiol. 19 : 436, 1907.
39. CANNON, W.B. and BURKET, I.R. : The endurance of anaemia bynerve cells in the myenteric plexus. Amer. J. Physiol.32 : 347, 1913.
40. CANTINO, D. : Sullo sviluppo dei plessi intramurale del canalealimentare nell'embrione di polio. Bull, Soc. Ital. Biol.Sper.42 -. 411, 1966.
41. CARAYON,A., PERQUIS, P. and COURBIL, L.J. : Resultatsde sixoperations d'Heller pour mega-oesophage chez I'Africain.Bull. Soc. Med. Afr. Noire Lang. Franc. 10 : 699, 1965.
42. CAREY, E. J. : Studies on the structure and function of the smallintestine. Anat. Rec. 21 : 189, 1921.
52
43. CARVALHO, M.M. de : Mai disfagico cardio-esofagico.Thesis, Graduate School University of Coimbra, Portugal, 1950.
44. CARVETH, S.W., SCHLEGEL, J.F., CODE, C.F. and ELLIS, F.H. Jr. :Esophageal motility after vagotomy, phrenicectomy, myotomyand myomectomy in dogs. Surg. Gynec. Obstet. 114 : 31, 1962,
45. CASSELA, R.R., BROWN, A.L., SAYRE, G.P. and ELLIS, F.H. Jr. :Achalasia of the esophagus : pathologic and etiologic considerations.Ann. Surg. 160 : 474, 1964.
46. CASSELA, R.R., ELLIS, F.H. Jr., and BROWN, A.L. : Fine-structurechanges in achalasia of the esophagus. Am. J. Path. 46 : 279, 1965.
47. CHABAL, J. and MENSAH, A. : The surgical treatment of idiopathicmega-esophagus in Africa. Bull. Soc. Med. Afr. Noire Lang.Franc. 10 : 163, 1909.
48. CHAGAS, C. : Nova tripanosomiase humana. Mem. Inst.Oswaldo Cruz.I : 159, 1909.
49. CHAGAS, C. Tripanosomiase americana ; forma aguda da moiestia.Mem. inst. Oswaldo Cruz. 8 : 37, 1916.
50. CHERNEY, L.S. : Intestinal stenosis following strangulated hernia.Ann. Surg. 148 : 991, 1958.
51. CHIN-CHE, C., SHAO-CHUAN, P. and CHE-JEN, K. : Clinicalstudy of 74 cases of congenital megacolon.Chin. Med. J. 82:295, 1963.
52. CHRISPIN, A.R. and FRIEDLAND, G.W. : A radiological study ofthe neural control of oesophageal vestibular function.Thorax. 21 : 422, 1966.
53. CODE, C.F. et al. : An atlas of esophageal motility in health anddisease. Thomas, Springfield, Illinois, 1958.
54. CODE, C.F. and SCHLEGEL, J.F. : personal communication, 1967.
55. CORELLI, D., CANCIULLO, D. and PANEBIANCO, G. :Cardiospasmo sperimentale con alterazione dei plessi nervosiintramurali dell'esofago epicardic—cardiale.Ann. Ital. Chir. 34: 144, 1957.
56. COZZI, F. and WILKINSON, A.W. : Oesophageal atresia.Lancet. 2 : 1222, 1967.
53
57. COZZ1, F. and WILKINSON, A.W. : Congenital abnormalities ofanus and rectum : mortality and function. Brit. Med. J.I : 144, 1968.
58. CREAMER, B., ANDERSON, H.A. and CODE, C.F. : Esophagealmotility in patients with scleroderma and related diseases.Gastroenterologia. 86:763,1956.
59. CREAMER, B., OLSEN, A.M. and CODE, C.F. : The esophagealsphincters in achalasia of the cardia (cardiospasm).Gastroenterology 33 : 293, 1957.
60. CROSS, F.S. : Pathologic changes in megaesophagus (esophagealdystonia). Surgery. 31:647,1952.
61. CULLIGAN, J.A. : Attempts to produce cardiospasm in the cat.Thesis, Graduate School, University of Minnesota, 1959.
62. CURRY, J.R. : What is your diagnosis ? J.A.V.M.A. 137: 27 (adverts)I960.
63. DALLE VALLE, A. : Richerche istologische sudi un caso di megacoloncongenito. Pediatra (Napoli). 28:740,1920.
64. DAVIS, D. and POYNTER, C.W.M. : Congenital occlusions of theintestines with report of a case of multiple atresia of the jejunum.Surg. Gynec. Obstet. 34 : 35, 1922.
65. DAVIS, D.R., DOCKERTY, M.B. and MAYO, C.W. : The myentericplexus in regional enteritis : a study of the number of ganglioncells in the ileum in 24 cases. Surg. Gynec. Obstet.101 : 208, 1955.
66. DE BRITO, T. and VASCONCELOS, E. : Necrotising arteritis inmega-esophagus. Histopathology of ninety-one biopsies takenfrom the cardia. Rev. Inst. Med. Trop. Sao Paulo. I : 195, 1959.
67. DE FREITAS, S.V. : Megacolo e megaesofago no BrasiI Central.Res. Clin. Cientifica. 19 : 411, 1950.
68. DEREYMEEKER, A. : Recherches experimentales sur I'origine du systemenerveux enterique chez I'embryon de poulet. Arch. Biol,54:359, 1943.
69. DE REZENDE, J.M. and RASSI, A. : Oesophagus involvement inChagas1 disease. Hospital (Rio). 53 : 1,1958.
70. DERRICK, E.H. and ST.GEORGE-GRUMBAUER, B.M. : Megacolonin mice. J-Path. Bact. 73 : 569, 1957.
54
71. DERRICK, J.R., POLLARD, H.S. and MOORE, R.M. : The patternof arteriosclerosis narrowing of the celiac and superior mesentericarteries. Ann. Surg. 149 : 684, 1959.
72. DESJARDINS, J.G., STEPHENS, C.A. and MOES, C.A.F. :Results of surgical treatment of congenital tracheo-esophagealfistula, with a note on cine-fluorographic findings.Ann. Surg. 160: 141, 1964.
73. DE V1LLIERS, D.R. : Ischaemia of the colon : an experimental study.Brit. J. Surg. 53 : 497-503, 1966.
74. DI BELLO, B. and ZILLI, L. : Associazone di cancro e megaesofagoinduefratlli. Acta. Chir. Ital. 16 : 267, I960.
75. DIXON, K.C. : Cerebral vulnerability to ischaemia.Lancet. 2 : 289, 1967.
76. DOGIEL, A.S. : Uber den Bau der Ganglien in des Geflechten desDarmes und der Gallenblase des Menschen und der Saugethiere.Arch. Anat. Physiol. 130,1899.
77. DOTT, N.M. : Anomalies of intestinal rotation.Brit. J. Surg. II : 251, 1933.
78. DUNBAR, J.D., MOLNAR, W., BEMAN, F.F. and MARABLE, S.A. :Compression of the celiac trunk and abdominal angina.Preliminary report of 15 cases. Amer. J. Roentgen. 95 : 731, 1965.
79. EARLAM, R.J., KURLAND, L.T. and ELLIS, F.H. Jr. : Epidemiologyof achalasia of the esophagus : incidence and prevalence in asmall urban community, (in preparation). 1968.
80. EARLAM, R.J., SCHLEGEL, J.F. and ELLIS, F.H. Jr. : Effect ofischaemia of lower esophagus and esophagogastric function oncanine esophageal motor function. J. Thorac. Cardiov. Surg.54 : 822, 1967.
81. EARLAM, R.J., ZOLLMAN, P.E. and ELLIS, F.H. Jr. : Congenitalesophageal achalasia in the dog. Thorax. 22 : 466, 1967.
82. EINHORN, M. : A case of dysphagia with dilatation of the esophagus.Med. Rec. and Ann. 34 : 751, 1888.
83. ELLIS, F.G. and COLE, F.C. : Reflux after cardiomyotomy.Gut. 6 : 80, 1965.
84. ELLIS, F.H. Jr. : personal communication. 1967.
85. ELLIS, F.H. Jr., KISER, J.C., SCHLEGEL, J.F., EARLAM, R.J.,McVEY, J.L. and OLSEN, A.M. : Esophagomyotomy for esophageal
achalasia : experimental clinical and manometric aspects.Ann. Surg. 166: 640, 1967.
86. ETZEL, E. : A avitaminose como agente etiologica do megaesofago edo megacolo. Ann. Fac. Med. S. Paulo. II : 59, 1935.
87. ETZEL, E. : Megaesophagus and its neuropathology - a clinical andanatomo-pathological research. Guy's Hosp. Gaz. 87 : 158, 1937.
88. ETZEL, E. : May the disease complex that includes megaesophagus(cardiospasm), megacolon and megaureter be caused by chronicVitamin B|deficiency? Amer. J. Med. Sci. 203 : 87, 1942.
89. FERREIRA-SANTOS, R. : Aperistalsis of the esophagus and colon(megaesophagus and Megacolon) etiologically related toChagas1 disease. Amer. J. Dig. Dis. 6 : 700, 1961.
90. FORSHALL, I. : Duodenal obstruction in the newborn with adescription of four cases. Brit. J. Surg. 35 : 58, 1947.
91. FORSHALL, I. : Hirschsprung's disease. J.R.C.S. (Ed). 10:31,1964.
92. FORSHALL, I. and RICKHAM, P.P. : Experiences of a neonatalsurgical unit. The first six years. Lancet. 2:151, I960.
93. FORSHALL, I., RICKHAM, P.P. and MOSSMAN, D.B. : Functionalintestinal obstruction in the newborn.Arch. Dis. Child. 26 : 294, 1951.
94. FREEMAN, N.V. : Congenital atresia and stenosis of the colon.Brit. J. Surg. 53 : 595, 1966.
95. GARTNER, F. : Multiple Atresien und Stenosen des Darmes bei einenneugeborenen Knaben. Jb. Kinderheilk. Phys. Erzieh. 20 : 403,1883.
96. GERBER, B.C. : Prepyloric diaphragm, an unusual abnormality.A case report. Arch. Surg. 90 : 472, 1965.
97. GETZ, B. and SIRNES, T. : Localisation within the dorsal motor nucleus.J. Comp. Neurol. 90 : 95, 1949.
98. GHABRIAL, F. : Hirschsprung's disease. Experience with the diseasein Egyptian infants and children, introducing a new modificationfor recto-sigmoidectomy. Kasr-el-Aini J. Surg. 5 : 307, 1964.
-
56
99. GIRDANY, B.R. : Hirschsprung's disease. Experience with the diseasein Egyptian infants and children, introducing a new modificationfor recto-sigmoidectomy. Kasr-el-Aini J. Surg. 5 : 307, 1964.
100. GLADSTONE, R.J. : Exhibit of lantern slides of 19 mm. embryo. InJ. Anat. 70 : 198, 1935. (quoted by Smith, 1957).
101. GOETZ, R.H. : The pathology of progressive systemic sclerosis(generalized scleroderma) with special reference to changesin the viscera. Clin. Proc. 4 : 337, 1945.
102. GORDON, H., TORRINGTON, M., LOUW, J.H. and CYWES, S. :A genetical study of Hirschsprung's disease ; congenital intestinalaganglionosis. S. Afr. Med. J. 40 : 720, 1966.
103. GOTTSTEIN, G. : Weitere Fortschritte in der Therapie chronischenCardiospasmus (mit sackartiger Erweiterung der Speiserohre).Arch. Klin. Chir. 87 : 497, 1908.
104. GRAIVIER, L. and SIEBER, W.K. : Hirschsprung's disease and mongolism.60 : 458, 1966. Surgery.
105. GRAY, H. : Anatomy of the Human Body. Ed. Goss, C.M. 28th Ed.Lea and Febiger, Philadelphia, 1966.
106. GREENHOUGH, W.G. : Congenital esophageal strictures.Amer. J. Roentgen. 92994, 1964.
107. GREENWOOD, R.K., SCHLEGEL, J.F. CODE, C.F. and ELLIS,F.H.Jr.:Effect of sympathectomy, vagotomy, and oesophageal interruptionon the canine gastro-oesophageal sphincter. Thorax. 17 : 310, 1962.
108. GREYING, R. : Die Innervation der Speiserohre. Z. Angew. Anat.Konstitlehre. 5 : 327, 1920.
109. GREWAL R.S., REEWAL, H.S. and NAGAR, A.M. : Congenitalmegacolon. J. Int. Coll. Surg. 43 : 61, 1965.
110. GROB, M. : Uber Lageanomalien des Magendarmtractus in folgeStorungen der Fetalen Darmdrehung. Benno Schwabe, Basel. 1953.
111. GROSS, R.E. : Surgery of infancy and childhood. Sounders,Philadelphia, 1953.
57
113. GUIMARES, J.P. : Megaesofago em macaco rhesus infectado peloS. Cruzi. Communicacao ao Congresso Internacional sobrea doenca de Chagas. Rio de Janeiro, 1959.
114. HAAS, R.M., TOUPET, A., DELARUE, J., POTET, F. and GUY, E. :Etude d'une jejunite segmentaire stenosante d'origineindeterminees avec hyperplasie des plexus nerveux myenteriques,etude medico-chirurgicale, radiologique et anatomo-pathologique.Arch. Mai. Appar. Dig. 53 : 864, 1964.
115. HAIGHT, C. : Some observations on esophageal atresias and tracheo-esophageal fistulas of congenital origin. J. Thorac. Cardiov.Surg. 34: 141, 1957.
116. HAMILTON, W.J., BOYD, J.D. and MOSSMAN, H.W. : HumanEmbryology. Williams and Wilkins, Baltimore, 1945.
117. HANDFORD. Dilatation of the oesophagus. Brit. Med. J. 2:885,1887.
hi118. HANDOUSA BEY, A.S. : Some rare anomalies of oesophagus : with
discussion of their aetiology. J. Laryng. 63:217, 1949.
119. HARMAN, J.W., O'HAGARTY, M.T. and BYRNES, C.K. : Theultrastructure of human smooth muscle : I. Studies of cellsurface and connections in normal and achalasia esophagealsmooth muscle. Exp. Molec. Path. I : 204, 1962.
120. HARRIS, L.D., ASHWORTH, W.D. and INGELFINGER, F.J. :Esophageal aperistalsis and achalasia produced in dogs byprolonged cholinesterase inhibition. J. Clin. Invest. 39 ; 1744,1960.
121. HEDRICK, R.M. : A trypanosome from the vig brown bat, (Eptesicusfuscus) Beauvois, Minnesota. J. Parasit. 41 : 629, 1955.
122. HELLER, E. : Extramukose cardioplastic beim chronischen Cardiospasmusmit Dilatation des Oesophagus. Mitt. a.d. Grenzgeb. d. Med.u. Chir. 27 : 141, 1913.
123. HELSINGEN, N. Jr. : Gastroesophageal reflux as a complication ofthe Heller operation. Acta Chir. Scand. Supp. 2356B : 96, 1966.
•
124. HERMAN, C.M. and BRUCE, J.I. Jr. : Occurrence of Trypanosoma Cruziin Maryland. Proc. Helminthological Soc. Washington.29 : 55, 1962.
125. HERTZ, A.F. : Achalasia of the cardia. Quart. J. Med. 8 : 300, 1915.
•-
58
126. HEVROWSKY, H. : Casuistik und Therapie der idiopathischenDilatation der Speiserohre oesophago-gastroanastomose.Arch. Klin. Chir. 100:703, 1913.
127. HIGGS, B. and ELLIS, F.H. Jr. : The effect of bilateral supranodosalvagotomy on canine esophageal function. Surgery, 58 : 828, 1965.
128. HIGGS, B., KERR, F.W.L. and ELLIS, F.H. Jr. : The experimentalproduction of esophageal achalasia by electrolytic lesionson the medulla. J. Thorac. Cardiov. Surg. 50 : 613, 1965.
129. HILL, C. J. : A contribution to our knowledge of the enteric plexuses.Phil. Trans. R. Soc. 215: 355, 1927.
130. HIRSCHSPRUNG, H. : Stuhltragheit Neugeborener infolge vonDilatation und Hypertrophie des Colons.Jb. Kinderheilk. Phys. Erzieh. 27 : I, 1888.
131. HOARE, C.A. : Does Chagas1 disease exist in Asia ?J. Trop. Med. Hyg. 66 : 297, 1963.
132. HOFFER, R.E., VALDES-DAPENA, A. and BADE, A.E. : Dog achalasiaand the lower esophageal sphincter. Surg. Forum. 17 : 334, 1966.
133. HOFFER, R.E., VALDES. DAPENA, A. and BADE, A.E. : A comparativestudy of naturally occurring canine achalasia.Arch. Surg. 95 : 83, 1967.
134. HOFFMAN, H.H. and SCHNITZLEIN, H.N. : The number of nervefibers in the vagus nerve of man. Anat. Rec. 139 : 429, 1961.
135. HOLINGER, P.M., JOHNSTON, K.C. and POTTS, W.J. : Congenitalanomalies of the esophagus. Ann. Otol. 60:707, 1951.
136. HUKURA, T., SDMI, T. and KOTANI, S. : The role of the ganglioncells in the small intestine taken in the intestinal intrinsic reflex.Jap. J. Physiol. II : 281, 1961.
137. HUKURA, T., SIINA, H. and FUKUDA, H. : Effects of destruction ofintra mural ganglion cells on the motility of the ileocecocolicregion. Jap. J. Physiol. 15 : 648, 1965.
138. HUNTER, R.H. : A case of megaduodenum with multiple anomalies ofthe ileum. Arch. Dis. Child. 8 : 155, 1933.
139. HWANG, K., ESSEX, H.E. and MANN, F.C. : A study of certainproblems resulting from vagotomy in dogs with special referenceto emesis. Amer. J. Physiol. 149 : 429, 1947.
59
140. INGALLS, T.H. and PRINDLE, R.A. : Esophageal atresia withtracheo-esophageal fistula. Epidemiologic and teratologicimplications. New Eng. J. Med. 240 : 987, 1949.
141. IORDANSKA1A, N.I. : Functional disorders of the vagus nerves incardiospasm. Vestn. K hir. Grekov. 88 : 24, 1962.
142. ISH1KAWA, N. : Experimentelle und klinische Untersuchungen uberdie Pathogenese und das Wesen des Megacolons.Mitt. a. d. Med. Fak. d. k. Univ. Kyushu Fukuoka. 7 : 339,1923.
m•* * *•• *
143. JABONERO, V. : Etudes sur le systeme neurovegetatif peripherique.Innervation de I'oesophage humain. A eta A not (Basel) 15 : 105,1952.
144. JACKSON, C. : Diaphragmatic pinchcock in so-called "cardiospasm".Laryngoscope. 32 : 139, 1922.
145. JEZIORO, Z., P1EGZA, S., MISTERKA, S. and SAPOTA, J. :Results of the surgical treatment of cardiospasm. Pol. Przegl.Chir. 38 : 187, 1966.
146. JOHNS, B.A.E. : Developmental changes in the oesophageal epitheliumof man. J. Anat. 86 : 431, 1952.
147. JOHNSON, S.E. : Experimental degeneration of the extrinsic nervesof the small intestine in relation to the structure of themyenteric plexus. J. Comp. Neurol. 38 : 299, 1925.
148. JORDAN, H.E. : A case of normal embryonic atresia of the esophagus.Proc. Nat. Acad. Sci. U.S.A. 3 : 264, 1917.
149. JOURDAN, F. and FANCON, G. : Mise en jeu du sphincter cardicque.Path. Biol. (Paris). 5 : 2049, 1957.
150. JURICA, E.J. : Studies on the motility of the denervated mammalianesophagus. Amer. J. Physiol. 77 : 371, 1926.
151. KATZ, J. and SENDER, H. : Cardiospasm in an African : a case report.S. Afr. Med. J. 33 : 1079, 1959.
152. KERNCAMP, H.C.H. and KANNING, H.H. : Primary megacolon(Hirschsprung's disease) in swine. N. Amer. Vet. 36 : 642, 1955.
153. KESSLER, E. and LINDEN, G. : Die postischamische Kontraktur desDarmes. Frankfurt Z. Path. 73 : 363, 1964.
154. KIEBEL F. and MALL, F.P. : Human embryology. Lippincott,Philadelphia, 1910.
6O
155. KIESEWETTER, W.B., SUKAROCHANA,K . and SIEBER, W.K. :The frequency of aganglionosis with imperforate anus.Surgery. 58 : 877, 1965.
156. KIMURA, K. : The nature of idiopathic esophagus dilatation.Jap. J. Gastroent. I : 199, 1929.
157. KIRKPATRICK, J.A., CRESSON, S.L. and PILLING, G.P. IV. :The motor activity of the esophagus in association withesophageal atresia and tracheo-esophageal fistula.Amer. J. Roentgen. 86 : 884, 1961.
158. KNOX, G. : Secular pattern of congenital oesophagea! atresia.Brit. J. Prev. Soc. Med. 13 : 222, 1959.
159. KOEBERLE, F. : Megacolon. J. Trop. Med. and Hya. 61 : 21, 1958.
160. KOEBERLE, F. : Chagas' disease : pathogenesis and importanceas an endemic disease. A contribution to the celebration ofits discovery 50 years ago. Tropenmed. Parasit. 10 : 236, 1959.
161. KOEBERLE, F. : Pathogenesis of Brazilian and European Megaesophaggs,Revta. Goiana. Med. 9 : 79, 1963.
162. KOEBERLE, F. : Enteromegaly and cardiomegaly in Chagas1 disease.Gut. 4:399, 1963.
163. KOEBERLE, F. and NADOR, E. : Eiologia e patogenia do megaesofagonoBrasil. Rev. Paul. Med. 47:643, 1955.
164. KOELE, W. : Der Kardiospasmus und seine Therapie mit transthorakalerOesophagokardiomyotomie. Wien. Med. Wschr. 112 : 747, 1962.
165. KOLOSSOW, N.G. : Der Nervenapparat der Speiserohre des Menschens.z. Mikrosk-Anat. Forsch. 65 : 529, 1959.
166. KUNTZ, A. : On the occurrence of reflex arcs in the myenteric plexusand submucous plexuses. Anat. Rec. 24 : 193, 1922.
167. KURLANDER, D.J., RASKIN, H.F., KIRSNER, J.B. and PALMER, W.L. :Therapeutic value of the pneumatic dilator in achalasia ofthe esophagus : long term results in 62 living patients.Gastroenterology. 45 : 604, 1963.
168. LADD, W.E. and GROSS, R.E. : Congenital malformations of theanus and rectum. Amer. J. Surg. 23 : 167, 1934.
61
169. LANGLEY, J.N. : Connexions of the enteric nerve cells.J. Physiol. 56: 39, 1922.
170. LAUFMANN, H., MARTIN, W.B., METHOD, H., TUELL, S.W. andHARDING, H. : Observations in strangulated obstruction. II. The fate
of sterile devascularized intestine in the peritoneal cavity.Arch. Surg. 59 : 550, 1949.
171. LAWN, A.M. : The localization, in the nucleus ambiguus of therabbit, of the cells of origin of motor nerve fibers in theglossopharyngeal nerve and various branches of the vagusnerve by means of retrograde degenerations.J. Comp. Neurol. 127 : 293, 1966.
172. LAWRENTJEW, B.I. : Experi mentell-morphologische Studien uberden feineren Bau des automenen Nervensystems. I. Z, Mikro-anat. Forsch. 18 : 233, 1929.
173. LEAMING, D.B. and CAUNA, N. : A qualitative and quantitativestudy of the myenteric plexus of the small intestine of the cat.J. Anat. 95 : 161, 1961.
174. LEIBOWITZ, S. and BODlAN, M. : A study of the vesical ganglia inchildren and the relationship to the megaureter, megacystissyndrome and Hirschsprung's disease. J. Clin. Path. 16 : 342, 1963.
175. LENDRUM, F.C. : The anatomical features of the cardiac orificeof the stomach, Thesis, Graduate School, University ofMinnesota, 1934.
176. LENDRUM, F .C. : Anatomic features of the cardiac orifice of thestomach with special reference to cardiospasm.Arch. Int. Med. 59 : 474, 1937.
177. LEWIS, F.T. : The development of the oesophagus. In Kiebel and Mall,Manual of Human Embryology. Vol. 2. Philadelphia, 1912.(quoted by Smith, 1957).
178. LIND, J.F., BLANCHARD, R.J. and GUYDA, H. : Esophageal motilityin tracheo-esophageal fistula and esophageal atresia.Surg. Gynec. Obstet, 123 : 557, 1966.
f t ^179. LION, G. : Retrecissement de Pextremite cardique de I'oesophage;
radiographique. Bull. Mem. Soc. Med. Paris. 23 : 401, 1906.
180. LISTER, J. : The blood supply of the oesophagus in relation to oesophagealatresia. Arch. Dis. Child. 39 : 131, 1964.
62
181. LOUW, J.H. : Congenital intestinal atresia and stenosis in thenewborn. Observations on its pathogenesis and treatment.Ann. Roy. Coll. Surg. Eng. 25 : 209, 1959.
182. LYNN, H.B. and Espinas, E.E. : Intestinal atresia : an attempt torelate location to embryologic processes. Arch. Surg. 79:357,1959.
183. McKEEVER, S., GORMAN, G.W. and NORMAN, L. : Occurrenceof a Trypanosoma Cruzi like organism in some mammals fromS.W. Georgia and N.W. Florida. J. Parasit. 44 : 583, 1958.
184. McMAHON, J.M., BRACELAND, F.I. and MOERSCH, H.J. :The psychosomatic aspects of cardiospasm.Ann. Int. Med. 34: 608, 1951.
185. McMANUS, J.E., PAINE, J.R., DAMERON, J.T., DUGAN, D.D. andEGAN, R.W. : Experimental study of extensive devascularisation and
denervation of the esophagus in dogs. Surg. Forum. 2 : 71, 1953,
186. MAGLIETTA, E.D. : Congenital aganglionic megacolon in adults :a case report. Arch. Surg. 81 : 598, I960.
187. MALM, A. : Cardioplasty in the surgical treatment of achalasiaof the esophagus. Scand. J. Clin. and Lab. Invest.Suppl. I. 1951.
188. MELTZER, S.G. : Ein Fall von Dysphagia nebst Bemerkungen.Berl. Klin. Wschr. 25 : 140, 1888.
189. MICHELS, N.A. • Blood supply and anatomy of the upper abdominalorgans. Lippincott, Philadelphia, 1955.
190. MIKULICZ, J. : Zur Pathologic und Therapie des Cardiospasmus.Deufcch. Med. Wschr. 30 : 17, 1904.
191. MOERSCH, H.J. : Cardiospasm in infancy and childhood.Amer. J. Dis. Child. 38 : 294, 1929.
192. MOERSCH, H.J. : Cardiospasm : its diagnosis and treatment.Ann. Surg. 98 : 232, 1933.
193. MOERSCH, H.J. : Discussion after paper by Holinger.Ann. Otol. 60 : 730, 1951.
194. MOHIUDDIN, A. • VagaI preganglionic fibers to the alimentary canal.J. Comp. Neurol. 99 : 289 : 1953.
195. MONCRIEF, J.A. and RANDOLPH, J.G. : Congenital tracheosophagealfistula without atresia of the esophagus : a method for diagnosisand surgical correction. Surgery. 51 : 434, 1966.
196. MOSHER, H.P. and McGREGOR, G.W. : A study of the lowerend of the esophagus. Ann. Otol. 37 : 12, 1928.
197. MOUTSOURIS, C. : The "solid" stage and congenital intestinalatresia. J. Pediat. Surg. I : 446, 1966.
198. MULDOON, J.P. and BAUTISTA, L.I. : Hirschsprung's disease :report of a case in a 39-year old adult. Dis.Col.Rect.5: 288, 1962.
199. MULLER, E., PERRON, G., GEREST, F. and^GIROUX, F. :%Un Cos de megaoesophage secondaire a une infection avirus neurotope. Bull. Mem. Soc. Med. Paris. 63 : 350,1947.
200. NAGATA, T. and STEGGERDA, F.R. : Histological study on thedeganglionated small intestine of the dog. Physiologist.6 : 242, 1963.
201. NAGLER, R.W., SCHWARTZ, R.D., STAHL, W.M. and SP1RO, H.M. :Achalasia in fraternal twins. Ann. Int. Med. 58 : 906, 1963.
202. NAWAR, G. : Experimental analysis of the origin of the autonomicgnaglia in the chick embryo. Amer. J. Anat. 99 : 473, 1956.
203. NEWCOM3E, H.B. : Familial tendencies in disease of children.Brit. J. Prev. Soc. Med. 20 : 49, 1966.
204. NIXON, H.H. ; Intestinal obstruction in the newborn.Arch. Dis. Child. 30 : 13, 1955.
205. OKAMOTO, E., IWASAKI, T., UEDA, T. and TAKEDA, Y. :Pathogenesis of cardiospasm : clinical and experimental studies.Med. J. Osaka. Univ. 14 : 245, 1964.
206. OKUMURA M., BRITO, T., da SILVA, L.H., da SILVA, A.C. andCORREA NETO, A. : Pathology of experimental Chagas1 disease in
mice. I. Rev. Inst. Med. Trop. Sao. Paulo. 2 : 17, I960.
207. OKUMURA M. and CORREA NETO, A. : Producao experimental de"megas" em animals inoculados Trypanosoma Cruzi. Rev.Hosp.Clin. 16:338, 1961.
208. OLSEN, A.M., HARRINGTON, S.W., MOERSCH, H.S. andANDERSEN, H.A. : The treatment of cardiospasm : analysis of a
twelve year experience. J. Thorac. Surg. 22 t 164, 1951.
209. OLSEN, A.M., HOLMAN, C.B. and ANDERSEN, H.A. : The diagnosisof cardiospasm. Dis. Chest. 23:477,1953.
64
210. PARKULAINEN,K .V. : Intrauterlne intussusception as a cause ofintestinal atresia. Surgery. 44 : 1106, 1958.
211. PARKULAINEN,K .V., HJELT, L. and SULAMAA, M. : Anal atresiacombined with aganglionic megacolon. Acta Chir. Scand.118 : 252, I960.
212. PAYNE, W.S., ELLIS, F.H. Jr. and OLSEN, A.M. : Achalasia ofthe esophagus : follow up study of patients undergoing esophago-myotomy. Arch. Surg. 81 : 41, I960.
213. PAYNE, W.S., ELLIS, F.H. Jr. and OLSEN, A.M. : Treatment ofcardiospasm (achalasia of the esophagus)! n children.Surgery. 50 : 731, 1961.
214. PELLERIN, D. : Malformations congenitales de I'anus et du rectum(imperforations anales). J. Chir. (Paris). 73 : 268, 1957.
215. PINOTTI, H.W. : Contribuicao para o estudo da fisiopatologia demegaesofago. Thesis, Graduate School, University of Sao Paulo,Brasil, 1964.
216. PRATA, A. : Aetiological relationship between Chagas1 disease andmegaesophagus. Rev. Brasil Med. 17 : 300, I960.
217. PRUZANSKI, W. and HUROS, A.G. : Smooth muscle involvement inprimary muscle disease. I. Myotonic dystrophy. II. Progressivemuscular dystrophy. Arch. Path. 83:229,1967.
218. PURTON, T. : An extraordinary case of distension of the oesophagus,forming a sac, extending from two inches below the pharynxto the cardiac orifice of the stomach. London Med. andPhys. J. 46:540, 1821.
219. RAIA, A., ACQUARONI, D. and CORREA NETO, A. : Pathogenesis andtreatment of acquired megaduodenum. Amer. J. Dig. Dis.6 : 757, 1961.
220. RAIA, A., ACQUARONI, D. and CORREA NETO, A. : Contribution tothe study of the pathogenesis of megaduodenum. Rev. GoianaMed. 7: I, 1961.
221. RAKE, G.W. : On the pathology of achalasia of the cardia. Guy'sHosp. Gaz. 77 : 141, 1927.
222. RASH, R.M. and THOMAS, M.D. : The intrinsic innervation of theGastro-oesophageal and Pyloro-duodenal junctions.J. Anat. 96:389, 1962.
65
223. REDO, S.F. and BAUER, C.H. : Management of achalasia in infancyand childhood. Surgery. 53:263,1963.
224. REID, J. : An experimental investigation into the glosso-pharyngeal,pneumogastric and spinal accessory nerves.Edinb. Med. and Surg. J. 51 : 269, 1839.
225. REUTER, S.R. and OLIN, T. : Stenosis of the eeliac artery .Radiology. 85 : 617, 1965.
226. RICHARDSON, K.C. : Electronmicroscopic observations on Auerbach'splexus in the rabbit, with special reference to the problem ofsmooth muscle innervation. Amer. J. Anat. 103 : 99, 1958.
227. RICKHAM, P.P. : Emergency alimentary tract surgery in the newborn.Brit. Med. J. I : 78, 1966.
228. RICKHAM, P.P. and BOECKMAN, C.R. : Achalasia of the oesophagusin young children. Clin. Pediat. (Phil.) 2 : 676, 1963.
229. RIEDER, W. : Histologische Studien an autonomenGanglienzellennach peripher Entnervung. Arch. Klin. Chir. 167 : 327, 1931.
230. RIKER, W.L. : Diagnosis and treatment of ageing I ionosis of the myentericplexus. Arch. Surg. 75 : 362, 1957.
231. ROBINSON, K.P. : Pyloric stenosis due to a mucosaI diaphragm.Brit. J. Surg. 54:397, 1967.
232. ROLLESTON, H.D. : Simple dilatation of the oesophagus. Trans. Path.Soc. Lond. 47 : 37, 1896.
233. ROSIN, J.D., BARGEN, J.A. and WAUGH, J.M. : Congenital megacolonof a man 54 years of age : report of a case.Proc. Mayo Clin. 25 : 710, 1950.
234. ROUBICEK, J. : The psychopathology and psychotherapy of cardiospasm.Gastroenterologia. 86 : 211, 1956.
235. SALZMAN, A.J. : Lower esophageal web associated with achalasiaof the esophagus. New York J. Med. 65 : 1922, 1965.
236. SANTULLI, T.V. and BLANC, W.A. : Congenital atresia of the intestinepathogenesis and treatment. Ann. Surg. 154:934, 1961.
237. SANTY, P., M1CHAUD, P. and LATREILLE. : Resultats du traitement dumegaoesophage par I "operation de Heller a props de 142 cas.Lyon Chir. 49 : 77, 1954.
66
238. SATO, H., AKIHAMA, M., TANAKA, T., etal. : Studies onidiopathic esophagus dilatation with special reference tothe compression interruption method with a glass plate andthe carbolic acid-injecting method used as intermuscularnervous plexus destroying methods. Jap. J. Gastroent.Part I. 71, 1963.
239. SAUER, M.E. and RUMBLE, C.T. : The number of nerve cells in themyenteric and submucous plexuses of the small intestine of thecat. A not. Rec. 96 : 373, 1946.
240. SCARO, personal communication, quoted by Okumura, 1964.
241. SCHMIDT, C.A. : Distribution of vagus and sacral nerves to the largeintestine. Proc. Soc. Exp. Biol. Med. 30 : 739, 1933.
242. SCHOFIELD, G .C. : Experimental studies on the myenteric plexusin mammals. J. Comp. Neurol. 119 : 159, 1962.
243. SCHREIBER, H.W. and BARTSCH, W.M. : Zur Atiologie des sogenanntenKardiospsmus und zur Problematik der Begutachtung.Munch. Med. Wschr. 100 : 1532, 1958.
244. SHAMMAA, M.H. and BENEDICT, E.B. : Esophageal webs : a report of58 cases and an attempt at classification.New Eng. J. Med. 259 : 0378, 1958.
245. SHAPIRO, A.L. and ROBILLARD, G.L. : The esophageal arteries,their configurational anatomy and variations in relation to surgery.Ann. Surg. I 31 : 171, I95O.
246. SHEPHARD, R., FENN, S. and SIEBER, W.K. : Esophageal function afterrepair of congenital lesions of the esophagus. Surgery. 59 : 608, 1966.
247. SMITH, E.I. : The early development of the trachea and esophagus inrelation to atresia of the esophagus and tracheo-esophageal fistula.In : Contributions to Embryology. Vol. 36. Carnegie Institute,Washington, 1957.
248. SOERGEL, K.H., ZBORALSKE F.F. andAMBERG, J.R. :Presbyesophagus. Esophageal motility in nonagenarians.J. Clin. Invest. 43 : 1472, 1964.
249. SOLOV'EVA, LA. : Development of the afferent innervation of theoesophagus in the chick. Arkh. Anat. 49 : 64, 1965.
250. SPASSOVA, J.M. : Ober die afferente Innervation der Speiserohre beimMenschen. Z. Mikrosk. Anat. Forsch. 65 : 327, 1959.
67
25L SPRIGGS, N.I. : Congenital intestinal occlusion. An account oftwenty-four unpublished cases, with remarks based thereon andupon the literature of the subject. Guy's Hosp. Gaz. 66 : 143, 1912,
252. STELZNER, F. and LIERSE, W. : Strukturanalyse des Oesophagus durch dasKarzinom. Thoraxchirurgie. 14:559, 1962.
253. STOHR, P. Jr. : Ergebnisse uber die mikroskopische Innervation desMagen-Darm-Kanals. Ergebn. Anat. Entwgesch. 34:250, 1952.
254. STONE, W.D., HENDRIX, T.R. and SCHUSTER, M.M. : Aganglionosis ofthe entire colon in an adolescent. Gastroenterology. 48 : 636, 1965.
255. STORSTEEN, K.A., KERNOHAN, J.W. and BARGEN, J.A. : The myentericplexus in chronic ulcerative colitis. Surg. Gynec. Obstet. 97 : 335, 1953,
256. STREETER, G.L. : Developmental horizons in human embryos. In :Contributions to Embryology. Vol. 32, Carnegie Institute.Washington, 1948.
257. SWENSON, O. : Congenital defects in the pelvic parasympathetic system.Arch. Dis. Child. 30 : I, 1955.
258. SWENSON,O., MERRILL, K. Jr., PIERCE, C. II. and RHEINLANDER, H.F. :Blood and nerve supply to the esophagus : an experimental study.J. Thorac. Surg. 19 : 462, 1950.
259. SWENSON, O. and OECONOMOPOULOS, C.T. : Achalasia of esophagusin children. J. Thoracic Cardiov. Surg. 41 : 49, 1961.
260. SZABO, T. and DUSSARDIER, M. : Les noyaux d'origine du nerf vaguechez le mouton. Z. Zellforsch. 63 : 247, 1964.
261. SZENTAGOTHAI, J. : The general visceral efferent column of the brain stem.Acta Morph. Hung. 2 : 313, 1952.
262. SZURSZEWSKI, J.H. : The relationship of the myenteric plexus to theelectrical and mechanical activity of the small intestine inunanesthetized animals. Thesis, Graduate School,University of Illinois, 1966.
263. SZURSKEWSKI, J.H. and STEGGERDA, F.R. : in preparation, 1968.
264. TABENSKI, Z. : On the innervation of the large intestine and microscopicexaminations in Hirschsprung's disease in children. Pol. Med J.5: 361, 1966.
265. TANDLER, J. : Zur Entwicklungsgeschichte des Menslichen Duodenum inFruhen Embryonal studien. Morph. Jb. 29 : 187, 1902.
68
266. TERRACOL and SWEET. Thoracic Surgery, 1958.
267. THIBERT, F., CHiCOINE, R., CHARTIER-RATELLE, G. et al :Forme familiale de I'achalasie de I'oesophage ehez I "enfant.Un. Med. Canada. 94 :I293, 1965.
268. TITTEL, K. : Uber eine angeborene Missbildung des Dickdarmes.Wien Klin. Wschr. 14 : 903, 1901.
269. TREACY, W.L., BAGGENSTOSS, A.M., SLOCUM, C.H. and CODE,O.F.Scleroderma of the esophagus. A correlation of histologic andphysiologic findings. Ann. Int. Med. 59 : 351, 1963.
270. TYCE, F.A. and BROUGH, W. : The appearance of an undescribedsyndrome and the inheritance of multiple diseases in threegenerations of a family. Phychiat. Res. Rep. 15 : 73, 1962.
271. UTKIN, V.V. : Some problems concerning the pathogenesis ofcardiospasm. Soviet Med. 27 : 16, 1964.
272. VAN CAMPENHOUT, E. : Further experiments on the origin of the entericnervous system in the chick. Physiol. Zool. 5 : 333, 1932.
273. VAN GOIDSENHOVEN, G.E., VAN TRAPPEN, G., VERBREKE, S. andVANDENBROUCKE, J. : Treatment of achalasia of the cardia with
pneumatic dilatations. Gastroenterology. 45:326, 1963.
274. VIERRA, C.B., MENEGHELLI, U.G. anddeGODOY, R.A. : Aspectosda secracao gastrica na forma cronica da molestia de Chagas.Hospital (Rio). 65: 2345, 1964.
275. VOGT, E.G. : Congenital esophageal atresia. Amer. J. Roentgen.32 : 463, 1929.
276. WADDELL, M.C. : Anatomical evidence for existence of enteric reflexarcs following degeneration of extrinsic nerves.Proc. Soc. Exp. Biol. Med. 26 : 867, 1929.
277. WALKER, A.W., KEMPSON, R.L. and TERNBERG, J.L. Aganglionosisof the small intestine. Surgery 60 : 449, 1966.
278. WALTON, A.J. : The surgical treatment of cardiospasm. Brit.J. Surg.12 :70I, 1925.
279. WALTON, B.C., BAUMAN, P.M., DIAMOND, L.S. and HERMAN, C.M.:Trypanosoma Cruzi in raccoons in Maryland. J. Parasit.42 : 20, 1956.
69
280. WANKE, R. and KRICKE, E. : Operative Behandlung der Achalasia(Sclerosis) cardiae, zugleich ein Beitrag zur Morphologie,Deutsch. Med. Wschr. 87 : 1036, 1962.
281. WANKE, R. and SCHUTTEMEYER, W. : Kritische Bemerkungen zumsogenannte kardiospasmus (sklerosis cardiae). Chir. 20 : 266, 1949.
282. WEBB, C.H. and WANGENSTEEN, O.H. : Congenital intestinal atresia.Amer. J. Dis. Child. 41 : 262, 1931.
283. WHITEHOUSE, F.R. and KERNOHAN, J.W. : Myenteric plexus incongenital megacolon : study of eleven cases.Arch. Int. Med. 82 : 75, 1948.
284. WILLIS, R.A. : The borderland of embryology and pathology.2nd Ed. Butterworth, Washington, 1962.
285. WILLIS, T. : Pharmaceuticae Rational is. London, Dring, Harper andLeigh, 1672.
286. WOOD, S.F. and WOOD, F.D. : Observations on vestors of Chaaas1
disease in the United States. Amer. J. Trop. Med. and Hyg.10, 155, 1961.
287. WOODY, NVC., HERNANDEZ, A. and SUCHOW, B. : AmericanTrypanosomiasis 111. J. Pediat. 66 : 107, 1965.
288. WOODY, N.C. and WOODY, H.B. : American Trypanosomiasis(Chagas1 disease). First indigenous case in the United States.J. Amer. Med. Ass. 159 : 676, 1955.
289. WOOLAM, G. and ELLIS, F.H. Jr. : in press. 1968.
290. WOOLER, G.H. : Cardiospasm. In : Modern Trends in Gastroenterology.(edited A very-Jones, A.) Butterworth, London, 1952.
291. YAMASK1, M. : Ein menschlicher Embryo von 8.5 mm. Scheitel-Steisslangemit fehlerhaften and ungewohnlichen Bildungen. Ab. aus dem Anat.Inst. d. Kaiserlich - Japanischen University z. Sendai. 15 : 27, 1933.
292. YANAGI, T. : Experimental studies on the genesis of idiopathic oesophagusdilatation. I. Relation between Auerbach's ganglion cells andcardiospasm. (Abstr. ) Jap. J. Gastroent. 3 : 167, 1931.
293. YNTEMA, C.L. : Depletions in cervical and thoraco-lumbar sympatheticsystem following removal of neural crest from embryo of chelydraserpentine. J. Morphol. 120:203,1966.
294. YNTEMA, C.L. and HAMMOND, W.S. : The origin of intrinsic gangliaof trunk viscera from vagal neural crest in the chick embryo.J. Comp, Neurol. 101 j 515, 1954.
295. YNTEMA, C.L. and HAMMOND, W.S. : Experiments on the origin anddevelopment of the sacral autonomic nerves in the chick embryo.Exp. Zool. 129:375, 1955.
296. YSANDER, F. j Human diplo-terata. Inaugural dissertation.Uppsala, 1925. (quoted Smith, 1957).
297. ZENKER, F.A. and von ZIEMSEN, H. : Handbuch der specie! lenPathologie und Therapie. Vogel, Leipzig, 1876.
298. ZENKER, R. personal communication, 1968.
299. ZENKER, R. and RUEFF, F.L. : Results of treatment of cardiospasm.Munch. Med. Wschr. 105 : 1437, 1963.