J. Neurol. Neurosurg. Psychiat., 1959, 22, 224.

CONGENITAL ARTERIOVENOUS FISTULA WITH AN ANEURYSMOF THE GREAT CEREBRAL VEIN AND HYDROCEPHALUS

TREATED SURGICALLYBY

JAMES B. GIBSON, ALEXANDER R. TAYLOR, and ALAN E. RICHARDSONFrom the Departments ofPathology and Neurological Surgery, Royal Victoria Hospital, Belfast

Aneurysms occasionally develop from the greatcerebral vein as a result of congenital arteriovenousfistulae. In a recent review Hirano and Terry (1958)referred to 18 cases, nine of which were confirmedat necropsy. The example of this rare conditionreported here presented as a case of hydrocephalusshowing certain noteworthy features. The conditionresponded well to surgical treatment, but the patientdied after a fall. The connexions of the aneurysmwere defined at necropsy.

Case ReportA baby girl of 6 months was brought for neuro-

surgical consultation because of obvious hydrocephalusin February, 1954. The pregnancy and delivery and theearly development of the infant had been normal, andfive weeks before she was examined she had been able tosit up almost unaided. At the time her balance hadbecome impaired and she no longer raised her headspontaneously. The skull was seen to be expanded andsuperficial scalp veins were prominent. The skull cir-cumference was 515 cm.; the fontanelle was half closedbut tense. Eye movements and pupillary reactions werenormal; no other abnormalities were detected. In radio-graphs of the skull, opening of sutures and finger mark-ings of the vault were seen but there was no evidence ofthe cause of the increased pressure. The transversesinuses were in their normal position and the posteriorfossa was not unduly shallow. At ventriculography, theintracranial pressure was high and an obstruction of theaqueduct was demonstrated, but not with the flask-shaped outline usually found in aqueduct stenosis. Theobstruction (Fig. I) began 2 cm. below the third ventricleand increased caudally giving rise to a "rat tail" shadow.The aqueduct was displaced forwards and downwardssuggesting a space-occupying lesion behind the pineal.To define this further, air was subsequently introducedby the lumbar route after the ventricular pressure hadbeen lowered. The radiological appearances then weresurprising (Fig. 2). All the subarachnoid cisterns weregreatly dilated, particularly the cistema ambiens. Thesulci of the cerebral convexities were considerablyenlarged up to the midline. These findings were inter-preted to indicate defective absorption of fluid at thesagittal sinus as the primary cause of the hydrocephalus.

224

It was thought that the resultant rise in fluid pressure inthe subarachnoid space had caused dilatation of thecisterns to such a degree that the cistema ambiens hadobstructed the aqueduct and so produced a type ofhydrocephalus which was at least intermittently non-communicating. To reverse this sequence an anasto-mosis between the spinal theca and the peritoneal cavitywas made with polythene tubing on February 25, 1954.The immediate result was highly satisfactory: skullexpansion ceased, the scalp veins became less distended,and normal development was resumed.At the age of I year the child could stand with support;

the skull circumference had increased by only 2 cm. At18 months she could stand unaided; the fontanelles wereclosed. She had a normal vocabulary and the motherthought her intelligence was normal. At 2 years she couldwalk, but her vocabulary seemed a little behind hercalendar age. At 3 years she appeared to be developingnormally. The skull circumference was 56 5 cm. The

FIG. 1.-Ventriculography at 6 months of age. There ismarked dilatation of the third ventricle and of the lateralventricles (overlapping). The third ventricle is displacedupwards and forwards by the aneurysm. The aqueduct,initially dilated, tapers off distally. This unusual type ofobstruction at the aqueduct has prevented air fromentering the fourth ventricle.

CONGENITAL INTRACRANIAL FISTULA ANEURYSM TREATED SURGICALLY 225

FIG. 2.-Encephalogram after introduction of air into lumbartheca at 6 months of age. Radiotranslucent patches markdilated subarachnoid cisterns and enlarge sulci overthe cerebral convexity. This unusual picture indicates afailure of absorption of cerebrospinal fluid.

scalp veins were still prominent but they were not dis-tended; abduction of the left eye was slightly impaired.At 41 years old she could walk and talk adequately. Hergait was a little unsteady at times but there were nolocalizing signs of cerebellar dysfunction.At 4 years and 8 months, in April, 1958, she fell while

playing, striking and bruising the left frontal area. Shequickly became drowsy and was admitted to hospitalwith a left hemiparesis and bilateral extensor plantarresponses. A diagnosis of acute intracranial bleeding wasmade but bilateral exploratory burr holes did not revealany haematoma; the brain was not under tension. Duringthe next two days she became more alert and recoveredthe power of the left limbs. Forty-eight hours afteradmission, however, she became cyanosed and apnoeic,apparently as a result of acute ischaemia ofthe brain-stem,and she died within two hours.

Post-mortem ExaminationPermission was granted for examination of the

head only. The operation sites in the skull were ina satisfactory state. The skull was deformed but notmarkedly enlarged. The brain weighed 2,000 g. Theconvolutions were flattened and the brain tissueswollen. There was marked cerebral hydrocephalicdeformity of the non-communicating type and thefourth ventricle was not enlarged; the lateral andmedial apertures of the ventricle were patent. Thesubarachnoid cisterns were not enlarged. The brainwas fixed entire together with the tentorium cerebelli,and subsequently sectioned in the coronal plane(Fig. 3). The ventricular system was obstructed atthe aqueduct. The obstruction was caused by anexternal spherical swelling about 4 cm. in diameter

with a fibrous wall. The swelling was an aneurysmextending downwards and forwards from theanterior end of the incisura tentorii and separatingthe brain-stem from the splenium. The antero-superior surface of this aneurysmal sac had stretchedthe posterior wall of the third ventricle, obliteratedthe recesses, and become firmly adherent to thepineal which was flattened antero-posteriorly.Hydrocephalic dilatation of the lateral ventriclesand the upward and lateral pressure of the swellinginto the calcarine fissures had thinned and flattenedthe medial surfaces of the occipital lobes so that themedial walls of the posterior horns of the lateralventricles were stretched and attenuated. The usualdeformities of cerebral hydrocephalus due toobstruction of the aqueduct were present, the cortexand white matter being reduced to a thickness ofabout 1-5 cm. in most places. The choroid plexuseswere normal. The aneurysmal mass stretched thequadrigeminal plate below it to a thin membraneand the aqueduct was reduced to a transverse slit(Fig. 3). The superior vermis was compressed andformed the floor of a concavity which included alsothe medial parts of the lateral lobes of the cerebellumon either side. The fourth ventricle was slightlyreduced in size.There were no scars of the tentorium cerebelli or

anything else to suggest previous tears and therewas no evidence of haemorrhage from the aneurysmat any time. The aneurysm involved the posteriorportion of the great cerebral vein and bulged down-wards from the origin of the straight sinus at itsorigin at the apex of the tentorium. The straight

FIG. 3.-Coronal section through the aneurysm and the hydrocephalicbrain at the level of the splenium, including the pons. A paleball thrombus occupies part of the aneurysm. The aqueduct ispatent but compressed below the aneurysm. The cerebral veinsare dilated.

226 JAMES B. GIBSON, ALEXANDER R. TAYLOR, AND ALAN E. RICHARDSON

sinus was dilated to 13 cm. diameter and had athick leathery wall. The torcula was an irregularlyshaped cavity about 2-5 cm. wide. The right trans-verse sinus was also dilated (1-2 cm. wide) and thickwalled. The left transverse sinus narrowed along itscourse and was 3 mm. wide at the point where thetentorium had been cut anteriorly. The superiorsagittal sinus was 4 mm. wide. The aneurysmcontained a white ball thrombus loosely adherent toits wall and not organized. The wall of the sac wasabout 1 mm. thick and microscopical examinationshowed that it was composed largely of elasticfibres and hyaline fibrous tissue formed in the intimaof the vein. A similar intimal proliferation causedthe thickening of the walls of the neighbouringvenous sinuses.On account of the stretching of the region, the

vascular connexions of the aneurysm were identifiedwith some difficulty and only after microscopicalexamination. It was possible, however, to locate andrecognize the major veins and arteries and these areshown in Fig. 4. Angiomas were not found. Thevessels were identified as follows.

Anteriorly both superficial middle cerebral veinswere dilated and their entries into the cavernoussinuses were enlarged. Over the lateral surfaces ofthe hemispheres, the right vein was more dilatedthan the left. The right deep middle cerebral veinconsisted of several small dilated vessels wbichdrained into the basal vein. The right basal veinpursued an approximately normal course lateral tothe cerebral peduncle and drained into the greatcerebral vein where it was dilated into the aneurysm(Fig. 4). The left deep middle cerebral vein wasdilated near its termination in the left basal vein onthe cerebral peduncle. This left basal vein endedabnormally on the medial surface of the hemispherebehind the thalamus, external to the choroidplexus, and, together with the thalamo-striate andchoroidal veins, gave origin to the left internalcerebral vein. The right internal cerebral vein wasalso identified by its origin in the thalamo-striateand choroidal veins on that side. Two-thirds of theway along its course it received an anomalousarterial tributary from the posterior cerebral artery,an arterio-venous fistula. The terminal third of thevein was dilated and varicose down to its terminationin the great cerebral vein. The proximal 1 cm. ofthe great cerebral vein, between its origin in theunion of the two internal cerebral veins and theaneurysm, was also dilated but not aneurysmal. Onthe right side it received a single small tributaryfrom the posterior wall of the third ventricle. Atthe point of origin of the aneurysm the vein wasjoined by an arteriovenous fistula which was 2 mm.wide, a long arterial vessel which ran across the

II

FIG. 4.-Semidiagrammatic representation of the aneurysm (2) atthe distal end of the great cerebral vein and its vascular con-nexions. Branches of the posterior cerebral artery (4) are shownin black. The artery on the right lies in front of the aneurysm.There are arteriovenous fistulae, on the left to the dilated anteriorportion of the great cerebral vein (5) where it enters the aneurys-mal portion, and on the right to the terminal portion of theinternal cerebral vein (3). Vessels containing mixed blood arecross-shaded. The right basal vein (1) ends in the aneurysm.The left basal vein (1) terminates abnormally at the origin ofthe left internal cerebral vein (3) which then passes in front ofthe aneurysm.

medial surface of the occipital lobe from the leftposterior cerebral artery. The conjoined vesselsentered the aneurysm at an angle, forming anopening 3 mm. wide in the lateral wall of theaneurysm. There were two other openings leadinginto the aneurysm, one of which was formed by theright basal vein and was 2 mm. wide. The inferiorsagittal sinus, which was dilated, opened into theupper surface of the aneurysm close to the termina-tion of the latter in the straight sinus. On microsco-pical examination, veins over the cerebrum, inthe basal nuclei, and over the cervical portion of thespinal cord were seen to be dilated and their wallswere fibrous. The arteries of the circle of Williswere normal.

DiscussionDeath resulted from the trauma sustained by the

child while playing. Post-traumatic cerebral oedemawas probably enhanced by the effects of the ball

CONGENITAL INTRACRANIAL FISTULA ANEUR YSM TREATED SURGICALLY 227

thrombus in the aneurysm. Increased secretoryactivity on the part of the choroid plexus may havecontributed to upset the delicate balance betweenproduction and absorption of cerebrospinal fluidwhich had been established by the previous theco-peritoneal drainage.

In the cases of Lumsden (1947) and of Clement,Gerbeaux, Combes-Hamelle, Pertuiset, and Petranca,(1954, Case 1) the aneurysms were found in infantsof 7 months and 1 month respectively and hadcaused subarachnoid haemorrhages. The ages ofthese cases and the location of the lesion mightsuggest that aneurysms of this type are caused bytrauma at birth. In our case, however, there wasnothing to indicate any previous tear of the ten-torium and the existence of arteriovenous fistulaepermits elimination of trauma as an aetiologicalfactor with even greater certainty. Hirano andTerry (1958) have listed the arterial connexions ofthe aneurysms in the 18 cases in the literature. In10 instances the posterior cerebral arteries wereinvolved alone, as in our case, or in combinationwith other cerebral arteries. The anterior cerebraland pericallosal arteries were involved in otherinstances. Russell and Nevin (1940) reported theabsence in their first case of any venous channelsleading through the jugular foramina, and theterminations of the superficial middle cerebral veinsin the cavernous sinuses were dilated. These ter-minations were dilated in our case too, but unfor-tunately the jugular foramina were not examined;the dilatation of the right transverse venous sinussuggests that drainage of blood was normal on thatside, but in view of the narrowing of the othertransverse sinus, the connexion of the left sigmoidsinus with the jugular vein may have been absent.Many of the deep and superficial cerebral veins onboth sides were dilated and tortuous because of theincreased entry of blood from the fistulae, but it waspossible to identify all the major channels withnormal anatomical elements. Thus, there was nogenuinely angiomatous element in the anomaly andthis seems to have been true also of the other caseswhich are discussed here, The extent of the venousanomalies described has varied considerably andmay depend in part on the size of the arteriovenousfistulae. In the case of Jaeger and Forbes (1946), inwhich both arteries and veins were considerablyenlarged, the fistula was big enough to lead tocardiac enlargement. The fistulae and the resultantaneurysm constitute a single entity, but it is to beexpected that the lesion might occur from time totime in combination with arteriovenous malfor-mations in other parts of the brain.

Superficial scalp veins are often dilated andprominent as in our case, because of their connexions

with the cerebral venous system. Dilatation ofsuperficial veins may be the presenting symptom(Boldrey and Miller, 1949). In the case of Hiranoand Terry (1958) dilatation of venous channelscaused protuberance of the right eye.At necropsy, the walls of many of the cerebral

veins were thick and fibrous, in keeping with theconsiderable degree of venous hypertension whichcertainly prevailed during life. The hypertensionwas probably the main factor impeding resorptionof cerebrospinal fluid through the arachnoidgranulations. In cases where subarachnoidhaemorrhages have occurred, thickening of theleptomeninges may also interfere with resorption(Askenasy, Herzberger, and Wijsenbeek, 1953) butthis complication was not present in our case. Thedilatation of the subarachnoid cisterns noted beforeoperation indicated that absorption of cerebrospinalfluid had been considerably impaired and thiselement of the hydrocephalus was relieved by thecaldrainage. After operation the circumference of thehead and the child's development began to approachnormal. The cisterns were not dilated at death. Theresidual clinical signs were probably caused directlyby the mass of the aneurysm. Possibly completerecession of the hydrocephalus was impossible at thistime. In the case of Hirano and Terry (1958) thearterial feeders of the aneurysm closed spontaneouslyand completely but the hydrocephalus did not recede.Askenasy et al. (1953) suggest that deviation ofarterial blood from the brain through the fistulaemay increase the degree of cerebral atrophy causedby the elevation in cerebrospinal fluid pressure, butthe clinical observations in our case do not supportthis suggestion. Although failure of absorptionseems to have played the chief part in the genesis ofthe hydrocephalus, the direct effects of the aneurysmin compressing the aqueduct cannot be neglected,and the hydrocephalus may have been maintainedto some extent by this means. The aqueduct was notcompletely closed, but obstruction may have beenintermittent, as apparently in the case of Jaegerand Forbes (1946). The balance between productionand absorption of cerebrospinal fluid achieved bythe operation was a delicate one and was eventuallyupset by trauma.

Hydrocephalus was absent in a number of thecases reported in adults and older children (Oscher-witz and Davidoff, 1947; French and Peyton, 1954)but it has been the main symptom in children. Theexperience in the present case suggests that cerebro-spinal fluid drainage operations have a useful partto play in its relief. Most often surgical treatmentof the condition has taken the form of clipping thearterial feeders as fully as possible. Hirano andTerry (1958) point out that the chief value of such

228 JAMES B. GIBSON, ALEXANDER R. TAYLOR, AND ALAN E. RICHARDSON

operations probably lies in preventing subarachnoidhaemorrhage and this complication has occurredoften enough to deserve serious consideration.Personality changes have been recorded by Frenchand Peyton (1954).The presence of dilated superficial veins on the

scalp in cases of hydrocephalus should arousesuspicion of the existence of an aneurysm of thegreat cerebral vein, and occasionally eye signs maysuggest the presence of a lesion in the region of thepineal. In the present case there was slight abductionweakness of the left eye. Wolfe and France (1949)mention papilloedema and also evidence of defectiveinnervation of the intrinsic and extrinsic musclesof the left eye. The patient of Jaeger and Forbesdeveloped a squint while under observation. Eyesigns were absent in the cases of Alpers and Forster(1945) and of Oscherwitz and Davidoff (1947).The diagnosis has most often been made by angiog-raphy but other radiological methods may be ofuse. The peculiar outline of the upper end of theaqueduct in the ventriculograms in our case maybe paralleled in others. In several cases in adultsthe wall of the aneurysm has been partially calcifiedso that the dilated vessel was outlined (Alpers andForster, 1945; Oscherwitz and Davidoff, 1947;Boldrey and Miller, 1949; Wolfe and France, 1949).The dilatation of the transverse sinuses might alsoin its turn lead to increased skull markings over thevessels, but the location of the sinuses on the skullis normal and they are not maintained in the foetalposition as in congenital hydrocephalus due toatresia of the foramen of Magendie (Taggart andWalker, 1942; Gibson, 1955).

SummaryIn a case of hydrocephalus caused by arteriovenous

fistulae and an aneurysm of the posterior part ofthe great cerebral vein, the history and the necropsyfindings in the head are recorded. Hydrocephalus

and dilatation of superficial scalp veins were notedat 6 months of age. The hydrocephalus was foundto be due in part to a failure of absorption of cerebro-spinal fluid which probably resulted from highvenous pressure in the superior sagittal sinus. Asurgical spinal theco-peritoneal anastomosis wasperformed with good results. Since the operationcompensated for the failure of absorption of cerebro-spinal fluid by the natural routes, defective absorptionappears to have played an important part in causingthe hydrocephalus. The child died as the result ofan accident when 4 years 8 months old. Theaneurysm was found to have caused persistent butincomplete obstruction of the aqueduct. Associatedvascular anomalies were marked dilatation of theanterior part of the great cerebral vein and of aportion of the right internal cerebral vein, arterio-venous fistulae on each side arising from branches ofthe posterior cerebral arteries, anomalous termina-tion of the left basal vein, and elongation anddilatation of veins in many parts of the centralnervous system. Angiomatous formations were notpresent. The case is discussed in relation to thosereported by others.We wish to thank Professor J. H. Biggart for advice

and encouragement and Mr. D. McA. Mehaffey for thephotographs.

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