proceedings society british neurological surgeons · cerbral cortex. chronic stimulation of the...

Journal of Neurology, Neurosurgery, and Psychiatry 1985;48:594-600

Proceedings of Society of the British NeurologicalSurgeonsThe 105th meeting of the Society was held in association with the Association of British Neurologists, inEdinburgh, 20-22 September 1984

A CRITIQUE OF THE NEUROSURGICAL MAN-

AGEMENT OF SPINAL TRAUMAP Harris (Edinburgh)Mr Harris opened the meeting by discus-sing the problems of spinal trauma, one ofthe most devastating forms of injury. Hereferred to an incidence of up to 20 or

more patients per million of the populationeach year, with a significant percentage ofsuch patients having an associated injury.Policies for the management of thesepatients vary, but central to their care is thequestion of prognosis. Unfortunately some

of the results of treatment in the earlyphase following injury had left much to bedesired, and some of these poor results hadbeen later managed by doctors who are

dedicated to specialising in the multi-disciplinary activities of spinal paralysisunits. Mr Harris considered that, becauseof his training and experience in neuraltrauma and in other spinal disorders, theneurosurgeon had much to offer the spinalinjured, in particular the necessary back-upof expert nursing staff and allied healthpersonnel, and close relationships with col-leagues in related specialities. He discussedthe indications for non-operative, and foroperative treatment for the traumaticspinal lesion, based on his personal experi-ence of several years, and concluded thatcontrolled, matched therapeutic trials wereneither practical nor ethical in the humansituation, and made reference to animalstudies as clues to the pathophysiology andtreatment.

NORMALIZATION OF ABNORMAL GLUCOSEMETABOLISM OF CEREBRAL CORTEX (PETSCAN) BY CHRONIC STIMULATION OF

ANTERIOR NUCLEUS OF THALMUS (FORLIMBIC LOBE EPILEPSY) OR ANTERIOR CERE-BELLUM (FOR SPASTICITY)IS Cooper, ARM Upton, S Garnett,I Amin, G Brown, M Springman (NewYork and Hamilton, USA)The authors had used positron emissiontomography, employing 18F-2-fluoro-2-deoxy- D-glucose. Two young adultpatients underwent stimulaton of anterior

lobe of the cerebellum (CCS) for treatmentof spacticity of cerebral palsy. Duringepochs when CCS was turned off there washyperactivity of glucose metabolism on oneside of cerebral cortex and hypometabol-ism on the opposite side. During epochswhen CCS was active there was normalisa-tion of glucose metabolism in the entirecerbral cortex. Chronic stimulation of theanterior nucleus of the thalamus (ANT) inpatients with intractable limbic systemepilepsy has been carried out at Westches-ter County Medical Center in New York,on the basis of a hypothesis that this mightinterrupt seizure activity in the limbic sys-tem while prosthetically mobilising inhibit-ory functions of the caudate nucleus. Ineach of two patients studied before opera-tions the principal abnormality washypoactive glucose metabolism in left tem-poral lobe. Complete normalisation of glu-cose metabolism in cerebral cortex occur-red only after simultaneous activation ofthe right and left ANT electrodes. Re-peated on-off studies confirmed thecause-effect relationship. During periodsof bilateral stimulation there was a statisti-cally significant reduction in seizures aswell as in EEG seizure discharges. Therewas a profound improvement in previouslyabnormal behaviour. Psychometric testingdemonstrated quantitative improvement inmotor function and memory. Valproic acidand dilantin blood levels rose after stimula-tion, requiring decreased dosages of eachdrug in both patients. The authors con-cluded that there appeared to be a closetemporal correlation between the clinicaleffects of stimulation of either cerebellumor the anterior nucleus of the thalamus andchanges in cerebral cortex glucose metabol-ism, as well as electro physiological,psychometric, and pharmacokinetic effects.

SUBEPENDYMOMA OF THE FOURTH VEN-TRICLE: A SURGICAL SERIESR Jooma, J Bradshaw, B Brownell,M Torrens (Bristol)Although a subependymoma of the fourthventricle is generally considered to be an

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incidental post-mortem finding, theauthors' clinical experience had promptedthem to draw the lesion to the attention ofneurosurgeons. They presented a surgicarseries of 12 patients diagnosed during a 13year period. There were nine males, theaverage age was 56 years and the averageduration of symptoms 3 years. Symptom'sof bulbar dysfunction had tended to pre-cede those of raised intracranial pressureby many months. Five ventriculograms, 10CT scans and one NMR scan wereyreviewed, in order to characterise the"typical" subependymoma. The tumourarose from the floor of the ventricle inseven cases, from the roof in two but in fIfurther two there was not an evidentattachment. In one patient, the origin was-from the lateral recess and the lesion pre-sented as an angle tumour. Alteration of'vital signs occurred during dissection of thetumours attached to the floor of the ventri-cle, and curtailed excision in all but one.There were five post-operative deaths,each due to respiratory failure. Review ofthe operative findings suggested that ihmost instances the surgeon had underesti-mated the size of the tumour as indicatedby radiology and as disclosed in the threecases that came to necropsy. The authors'message was that the diagnosis of a sub-ependymoma should be considered in anyadult presenting with a fourth ventriculartumour. Even though the tumour is higtologically benign, it is usually extensive atthe time of presentation and operation is'associated with hazards, in particular, a lia-bility to apnoea after operation. Thephoped that use of surgical tools such as theultrasonic aspirator or laser would improveresults.

MANAGEMENT OF INTRACRANIAL ABSCESS: AREVIEW OF 113 CASESES Miller, PS Dias, D Uttley (London)Recent studies suggest that mortality ofcerebral abscess may have been reduced.The aim of this paper was to examine fac-tors that might be responsible and con-versely those features still associated with a

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Proceedings of Society of the British Neurological Surgeons

high mortality. The review covered the,.years between 1971 and 1983 and included113 patients treated in their unit. This sug-gested an average annual incidence of2-9/million population. The primary focus

-of infection was classified as: ENT: 59patients, thoracic: 13 patients, unknown:30 patients, other: 11 patients. The onlyclinical feature significantly related to out-,come was level of consciousness; 21patients either responding only to painfulstimuli or not responding, had a mortalityof 60%. Ninety-two patients who were

,obeying command had a mortality of 17%.Overall the mortality was 26%. Thegroup's experience suggested that theintroduction of computed tomography hadjmade possible accurate localisation of allintracranial abscesses. Ninety-five patientswere correctly diagnosed and their abscesslocalised before treatment, 12 were diag-nosed at operation, six had abscesses eitherdiagnosed or localised correctly only atpost-mortem, of whom five had not had anoperation. Sixty-three patients were tre-ated by burr hole aspiration alone, eighthad burr hole aspiration followed by exci-sion, 32 had primary excision of the abs-cess, two were managed conservatively..The mortality in these groups were 20%,25%, 25% and 0% respectively. The onlychange in antimicrobial therapy had beenthe introduction of metronidazole. Theauthors re-emphasised that future attemptsto improve in management must bedirected towards earlier recognition andspeedier referral of cases and promptneurosurgical management.

FIFTY YEARS EXPERIENCE WITH CHORDOMASIN SOUTH-EAST SCOTLANDP O'Neill, BA Bell, I Jacobson, JD Miller(Edinburgh & Dundee)Chordomas are relatively rare malignantneoplasms, the mean annual incidence inone series being 0-3 males and 0-18

Vfemales per one million population. Thislimits an individual clinician's experiencewith the tumour. The authors thereforereported the clinical presentation andmanagement of 34 patients with a histolog-ically proven chordoma, who had beentreated in the neurosurgical departments inEdinburgh and Dundee, over the past 50

_years. The tumours involved three mainareas of the neuraxis: intracanial (35%),sacro-coccygeal (53%) with only four(12%) in the rest of the vertebral column.

,With an intracranial tumour, cranial nerve

palsies were almost invariable as present-ing signs. In contrast, the presentation of

sacrococcygeal tumours seemed to berelated more to the mass effect of thelesion than to its capacity to involve adja-cent neural structures, so that back pain,bowel disturbance and a palpable masswere each relatively common. The meansurvival in patients with an intracranialchordoma was 7*7 years, with sacro-coccygeal chordomas was 7-2 years. Therewere too few vertebral tumours to providea reliable estimate of mean survival time.The Edinburgh and Dundee workersexperience led them to recommend aggres-sive surgery and radiotherapy as theoptimum treatment. The combination ofhyperthermia and chemotherapy hadshown some promise in a few cases but hadnot been tested in a sufficient number ofpatients. Definitive studies would require amulticentre trial and extremely longfollow-up.

CAROTID LIGATION- WHAT HAPPENS IN THELONG TERM?AN Jha, P Butler, RA Fawcitt, RH Lye(Manchester)Common carotid ligation is occasionallyused in the treatment of giant or inaccess-ible intracranial aneurysms. There havebeen few long-term studies of patients whohave undergone this procedure. Theauthors reviewed a series of 115 patientswho, over the period 1954-1984 under-went common carotid ligation. Seventy-three of the patients presented with a sub-arachnoid haemorrhage and 42 patientshad mass effects from an unrupturedaneurysm. Average age at ligation was 50years (22-77 years) and of a total of 141aneurysms demonstrated, the distributionwas: posterior communicating artery 65;other internal carotid artery sites 45;anterior communicating artery 20; middlecerebral artery 11. Multiple aneurysmswere present in 16 patients. Case historieswere reviewed and patients recalled.Thirty-nine patients were lost to follow-upafter a variable period (mean 3-75 years).Of the remaining 76 patients, 26 had died.Nineteen of the 26 deaths were 6 monthsor more after ligation and 13 of these werecaused by proven or suspected recurrenthaemorrhage. Check angiograms wereobtained from 55 patients after a meaninterval of 8-4 years following carotid liga-tion (42 patients underwent digitalintravenous arteriograms; 13 had conven-tional angiography). Of 67 aneurysms pre-sent before ligation, 40 were not seen, 11were smaller, 15 were unchanged and one

aneurysm had enlarged. New aneurysms

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were noted in four patients. Annual mor-tality for those patients traced was 1-5%and the projected annual mortality (lost tofollow-up, presumed dead) was 4*3%.Common carotid ligation may offer earlyprotection from fatal recurrent haemor-rhage and it appears to reduce the size ofmany aneurysms. However, the authorsconcluded that the procedure does notappear to reduce significantly the long termprognosis for fatal recurrent haemorrhagecompared with that of the natural historyof anterior circulation aneurysms.

FURTHER EXPERIENCE IN STEREOTACTICPONTINE TRACTOTOMYER Hitchcock, MC Kim, MG Sotelo(Birmingham)The value of cordotomy for the relief ofintractable pain is well established but it isnot always possible to limit the destructionto the spinothalamic tract and avoid injuryto associated fibres. Damage to thedescending respiratory pathway is particu-larly dangerous and cervical cordotomyoften fails to relieve pain at high levels.Stereotactic radiofrequency pontinespinothalamic tractotomy has the advan-tage that the separation of autonomic andpain pathways at pontine level permits highanalgesic levels avoiding any accompany-ing disorders of micturition or respiration.The authors reported that they had foundstereotactic pontine tractotomy most suit-able for recurrent intractable pain, needinghigh level analgesia and in patients withpoor respiratory function. The procedurewas less complex and difficult than mightappear but precise stereotactic instrumen-tation was essential. Experience withselected patients was described, and illus-trated that reliable pain relief of long dura-tion without gross complications and withwell sustained analgesia could be achieved.

CRANIAL DURAL ARTERIO-VENOURS FIS-TULAED Gentleman, E Teasdale (Glasgow)Cranial dural arteriovenous fistulae werefirst described in 1931, but were infre-quently diagnosed before the introductionof superselective catheter angiography inthe 1970s. In order to illustrate the clinicalfeatures, management, and outcome oftreatment, the authors reported five maleand three female patients; the mean agewas 54 (range 30-69). Four presented withsudden headache, and one each with grandmal seizures, sudden loud bruit, unilateral



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proptosis and ophthalmoplegia, and finallydrowsiness following head injury. Whenadmitted to hospital, three patients hadaltered conscious level, three had focalneurological deficits and three had a cranialbruit. Five were considered to have had anintracranial haemorrhage. Cerebral CTscanning, showed an intracranialhaematoma in four cases and a dilated ves-sel in a fifth. In each patient, catheterangiography of the carotid and/or vertebralcirculation demonstrated the dural fistula,and in seven cases the lesion was embolisedwith Lyodura after superselective catheter-isation. The remaining patient's fistula wassupplied chiefly by the internal carotidartery. Sixteen angiographic procedureswere carried out in these seven patients.Three became asymptomatic after oneembolisation, and another after two. Theearliest patient required five embolisationsto abolish her symptoms. The sixth patienthad recurrent tinnitus after each of fourprocedures, and in the seventh patient onlyone out of two major feeding vessels couldbe embolised; this patient is awaitingfurther treatment. Complications of embol-isation were: one patient had a transienthemiparesis, and two had facial pain forseveral weeks. At follow-up between sixand 35 months later, all patients were alive,and none had suffered a recurrent haemor-rhage. One had continuing fits, and anotherhad persistent tinnitus. Their experienceled the authors to conclude that duralfistulae were often complex and in sitesthat cautioned against surgical removal;they considered that therapeutic embolisa-tion, via superselective catheter angiogra-phy, offered an alternative method oftreatment that was safe and usually effec-tive.

THE CLINICAL SPECTRUM OF HEAD INJURYJD Miller, P Jones (Edinburgh)Current interest in the management ofhead injury focuses on policies for admis-sion and skull radiography, and for transferto neurosurgical units, and CT scanning,also the prevalence of systemic insults andavoidable intracranial complications.Because of selective admission policies,experience in most neurosurgical units inthe UK is biased heavily toward the mostseverely head injured. The practice inEdinburgh, where all head injured patientsadmitted to the Royal Infirmary are underthe care of the regional Department ofSurgical Neurology, had provided theauthors with an opportunity to service thefull clinical range of head injury. They


compared 1919 cases of head injury admit-ted in 1981 with 1492 cases admitted in1982, after their admission policy had beenchanged, and 1 179 cases admitted in 1983,during most of which time the revised seatbelt legislation was in force. Patients were

subdivided into mild, moderate and severe

categories according to the admission score

on the Glasgow Coma Scale. Of the 1919patients admitted in 1981 1616 (84%)were mild (7 deaths), 210 (1 1 %) moderate(6 deaths) and 93 (5%) severe (42 deaths).The change in admission policy, permittingdischarge from A & E of certain patientswith a history of loss of consciousness, was

followed by a marked fall in head injuryadmissions. This was confined to mildcases, and the number of moderate/severecases and the mortality were notsignificantly affected. Similarly, althoughthe enactment of new seat belt legislationwas followed by a reduction in the numbersand severity of injured in drivers and frontseat passengers, the total numbers of mod-erate and serious head injury cases and thetotal head injury mortality did not change.The authors emphasised that, although fewin proportion to overall numbers, therewere many patients with apparently minorinjuries who did have other major prob-lems and that the proper care of these cal-led for a major commitment in time andresources.

THE PROVENANCE OF EXTRADURALHAEMATOMAD Sandeman, B Cummins (Bristol)The publication of guidelines, devised by a

group of neurosurgeons, for the manage-

ment of head injuries had prompted a

review of 100 extradural haematoma(EDH) who had presented to the authors'unit in the last ten years. Fifty seven were

adults and 36 children. Thirty-sevenpatients presented to the referring Acci-dent Centre with the signs of an extraduralalready developing; 55 patients developedsigns while under observation. All the chil-dren and 42 of the adults developed thesigns of EDH within 48 hours of the injury.In the remaining adults the diagnosis was

delayed until after 48 hours. Only five ofthese developed clinical signs; the other 10had a CT scan because of persisting symp-

toms, without neurological signs. Only twopatients showed the classical lucid intervalbetween periods of unconsciousness, 93%of adults had a skull fracture but 33% ofchildren did not. The published criteria foradmission and skull radiography were

applied retrospectively to each patient.

Eighty-nine of the patients would havebeen admitted, 64 because of confusion ordepression of the level of consciousness oninitial assessment, seven because ofneurological symptoms or signs alone and19 because of skull fracture alone. Of thelatter, 10 would have had radiographybecause of a history of unconsciousness oramnesia, three because of a suspected CSFleak, but in five the only indication forradiography would have been the presenceof a scalp haematoma or laceration. Fourpatients would not have been admitted. Intwo a skull fracture was missed on radiog-raphy. The other two cases were childrenwho did not have skull fractures. (Againthe only indication for radiography of thesechildren was the presence of a scalp contu-sion). In one of these four patients the clin-ical diagnosis of EDH was made three daysafter injury, but the other three developed ttheir signs less than 36 hours after injury.The authors emphasised two points: (1) rThat the diagnosis of a skull fracture wascrucial in the assessment of alert adultpatients and that often the only clue to afracture was a scalp haematoma or lacera-tion. (2) That there were difficulties in theassessment of children but that most chil-dren should develop signs of the theirextradural within a 48 hour period of 1observation. They concluded that allpatients with a scalp laceration or contu-sion should have skull radiographs and thatgreat care must be taken with the assess-ment of head injured children.

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CORRELATION OF TARGET SITE WITH HIS-TOLOGY AND CELL CULTURE IN CT-DIRECTEDSTEREOTACTIC BIOPSYM Powell, J Olney, J Darling, D Thomas(London)Initial clinical experience of the use of theBrown Roberts Wells frame for CT-directed stereotactic brain biopsy had beenreported previously to the Society. In thissecond series, the group's aims had been tostudy histological variation in relation toCT biopsy site and also to correlate thiswith cell culture. They had studied 38cases: 26 gliomas, 3 secondary carcinomas,'5 miscellaneous tumours" (Sarcoid, Ger-minoma, Pinealoma, Craniopharyngioma,and Primary brain lymphoma) and fourcases where identifiable tumour was notobtained. They considered that CT biopsyhad remained relatively safe with no deathsbut there had been four deteriorations, twotemporary, attributable to the procedure.'They had taken biopsy specimens from at



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Proceedings of Society of the British Neurological Surgeonsleast two sites within the tumour: thecentre and the enhancing edge. In 15 of the34 tumours (44-1%) there were clear his-

_ tological differences between tumourcentre and its edge as defined by CT.Indeed in 10 (29.4%) cases the edge washistologically tumour free. In the 26gliomas, 13 (50%) cases showed a histolog-ical difference and 8 (30.8%) were tumourfree at the edge. They concluded, tenta-tively, that the brain beyond the apparentenhancing boundary on CT may be free oftumour even in a malignant glioma. Theresults of cell culture neither confirmed nordenied their hypothesis. Of 36 patientsamples 10, (28%) failed to grow; seven ofthese were from tumour types which rarelygrow in culture (eg craniopharyngioma). Inone case where an equivocal histologicalreport was received a tumour was grown,and in another, the histological tumour freeedge also grew cells. Both of these wouldbe explained by slight differences in singletarget sites.

CLINICAL ASSESSMENT OF PATIENTS WITHSUBARACHNOID HAEMORRHAGEG Teasdale, K Lindsay, S Dharker, G MillExisting scales for grading patients with arecent subarachnoid haemorrhage have ahigh inter-observer variability. The WorldFederation of Neurosurgical societies hasestablished a committee with the task ofsearching for a clearly defined, practicalway of assessing patients. One proposalbeing studied is that an assessment of the

'Glasgow Coma Scale should be combinedwith other clinical features of intracranialhaemorrhage (Teasdale, Lindsay andKnill-Jones, Neurosurgery 1983). Toexamine if this can be a useful index theauthors analysed, in a retrospective study,the incidence of different degrees ofimpaired consciousness, of features of men-ingism such as headache and neck stiffness,and of focal deficits. They had studied in141 patients the frequency of differentcombinations and how these correlatedwith outcome and with previous scales. In

the light of the results a simple five pointscale was proposed.The authors reported that when there weredifferences in scores on previous scales andthe new method, the latter usually pro-vided the more appropriate index of prog-nosis and also had a higher inter-observerconsistency. They recommended it as asimple and effective method for assessingpatients with subarachnoid haemorrhage.

SEQUENTIAL CEREBRAL BLOOD FLOWS FOL-LOWING SUBARACHNOID HAEMORRHAGE -IS IT AN AID TO MANAGEMENT?EW Mee, DE Dorrance, LZ Barsoum,DG Hunter, G Neil-Dwyer (London)The object of this prospective study was toascertain if daily serial measurement ofcerebral blood flows (CBF) had a role inthe clinical management of patients whohad suffered a subarachnoid haemorrhage(SAH). The 23 patients, from a sequentialseries of 50 admitted to the authors unit,were those who proceeded to surgery forclipping of an intracranial aneurysm and onwhom daily pre-, per- and post-operativemeasurements had been made, using the133 Xenon rebreathing technique. Thepatients clinical grade and blood pressurewere also recorded daily. The presence orabsence of blood on the CT scan and cere-bral angiographic findings were also noted.The CBFs were adjusted for age and sexand were expressed in terms of the numberof standard deviations by which they dif-fered from the expected. The study wasdivided into three phases: (a) preoperative,(b) peroperative and (c) postoperative.Three outcomes recognised: (a) sevenpatients who had no postoperative compli-cations and made a full recovery, (b) 12patients who had postoperative complica-tions but who made a full recovery and (c)four patients who had major postoperativecomplications and have major neurologicaldeficits more than three months postopera-tively or who have died (n = 1). The results

Grade GCS Headachel Frequency in day before operationNeck Best % Poor Worst % Poorstiffiess State Outcome State Outcome

I 15 0 11% 0 9% 0II 15 Present 71% 23 39% 16III 13/14 16% 36 47% 29IV 8-12 + 1% 4%

67 63V <7 + 1%J 1%,(GCS = Glasgow Coma Score; Poor Outcome = dead, vegetative or severe disabilityat 3 months)

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showed the following general patterns. Inpatients whose CBFs were rising at thetime of surgery there were fewer post-operative complications and all had a goodoutcome. By contrast, if the preoperativeflows were falling at the time of surgerythere were more frequent and severe post-operative complications and the final out-come tended to be poorer. These observa-tions were independent of the patientspreoperative clinical condition. Peropera-tively falling CBF measurements wereindicative of more postoperative complica-tions and a poorer outcome whilst risingflows suggested fewer postoperative com-plications and a better outcome. Theauthors suggested their preoperative CBFmeasurements might be useful in clinicalmanagement, a negative slope being anindication of a stormy postoperative courseand/or poor outcome, whilst a positiveslope is suggestive of fewer postoperativeproblems and a good recovery.

DIPYRIDAMOLE IN POST-OPERATIVE VASO-SPASMMDM Shaw, PM Foy, JD Pickard,M Conway, J Spillane, DW Chadwick(Liverpool and Southampton)Cerebral ischaemia remains a potent causeof death and disability after surgery foraneurysmal subarachnoid haemorrhage.Vasospasm has been considered to be thecause but some recent evidence suggeststhat the basic underlying problem may be aproliferative vasculopathy. The authorsnoted that, although the role of theplatelets in this event is not clear, release ofplatelet factors into the vessel wall couldresult in medial hypertrophy, and hence tovessel narrowing. Furthermore, the disag-gregation that occurs could during plateletthrombus formation lead to the release ofsmall platelet emboli. Dipyridamole canreduce new platelet aggregation andreverse platelets adherence at the site of avascular injury. These observations had ledto a collaborative randomised trial to dis-cover if dipyridamole reduced the fre-quency of ischaemic complications follow-ing surgery for aneurysmal subarachnoidhaemorrhage. Six hundred and seventy-seven patients were randomised, of whom348 underwent surgery. There was not asignificant difference between the patientsrandomised to dipyridamole as comparedwith those on placebo, in respect of theirpre-operative clinical condition, grading(Hunt and Hess), and peroperativefindings; however more patients onplacebo had subarachnoid blood whilst



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more in the dipyridamole group had tight,stiff brains. The results showed that theoutcome of the dipyridamole and placebogroups did not differ significantly withrespect to mortality or morbidity (GlasgowOutcome Scale). No untoward haemostaticproblems were found in the dipyridamolegroup and in particular there was no evi-dence of an increased risk of re-haemorrhage pre-operatively. The resultstherefore did not support the use ofdipyridamole in this dosage, but did notexclude a role of platelets in vascularevents after subarachnoid haemorrhage.

EXTRAOPERATIVE CORTICAL MAPPING INEPILEPTIC PATIENTS USING CHRONICALLYIMPLANTED SUBDURAL ELECTRODESIA Awad, JF Hahn, R Lesser, H Lueders(Cleveland, Ohio, USA)The surgical treatment of seizures requiresmaximum resection of epileptogenic cortexwhile sparing functionally vital tissue. Inpractice, recognition of the optimum line ofresection is difficult. Forty-eight patientsunderwent a craniotomy during which sub-dural electrodes were implanted. Thepatients were then maintained onintravenous antibiotics for a mean of 13days, during which they underwent inten-sive monitoring. Using the implanted elec-trodes, the motor and speech areas weremapped by cortical stimulation: the sen-sory and auditory areas were mapped byevoked potential recording: and, preciselocalisation of epileptogenic cortex wasaccomplished by direct extraoperative elec-trocorticography. Patients then underwenta second craniotomy, the electrodes wereremoved, and the seizure focus wasexcised. The authors found that there wasmarked variability of cortical locatisationin individual patients. Also, the seizurefocus was not always limited to temporallobe, and occasionally involved frontal,parietal, or occipital areas. The standard' temporal lobectomy" using classical corti-cal landmarks would have failed to resectthe mapped seizure focus in of 12 of 48patients and would have resected cortexdefined as functional in 18 patients. Theauthors considered that the advantages ofthe method included the feasibility ofextensive and unhastened monitoring out-side the operating theatre, the avoidance ofcraniotomy under local anaesthesia, andprovision of a rational and extensive resec-tion strategy for each individual patient.These outweighed the disadvantages,which included the risks of infection (two


patients), and electrode intolerance, whichnecessitated early removal of electrodes intwo patients.

DEMENTIA DUE TO MENINGIOMA- OUTCOMEAFTER SURGICAL REMOVALCP Chee, AS David, SL Galbraith,RA Gillham (Glasgow)Dementia is a common presentation ofpatients with an intracranial meningioma.The condition has usually been present fora long time, and it is customary to be cauti-ous about the prospects of improvementafter operation. The authors drew atten-tion to the lack of a systematic study of theoutcome of such cases and therefore hadstudied the effects of operation in patientswith dementia was due to meningioma.The study was retrospective, and dementiadefined as a progressive disintegration ofintellect, of memory and of the powers ofabstract thought. Between June 1981 andOctober 1983, 38 patients were diagnosedto have an intracranial meningioma, 10(26%) of these had presented with demen-tia. The family of a 79 year old man did notwish him to have an operation, leaving ninecases for study. One patient died from apulmonary embolus two weeks after opera-tion. Another who had a middle thirdparasagittal meningioma remained akineticand mute post operatively and died sixmonths later. Of the remaining sevenpatients, five were described as normal atfollow-up six months later. Formalpsychometric assessment in four of thesepatients confirmed the intellectualimprovement. One other had improved butremained disinhibited and one did notimprove. Incontinence was cured in threeof four patients. The authors concludedthat their findings showed that afterremoval of a meningioma improvementfrom dementia was usual, but not uniform.Although two patients died without recov-ering, at least half recovered, apparentlyfully.

FORTY TWO CASES OF INTRACRANIALOLIGODENDROGLIOMA IN CAMBRIDGE IN1961-1984IMS Wilkinson, AE Holmes (Cambridge)The authors had collaborated to reviewpresenting features, management and out-come of 41 patients with an oligodendrog-lioma.There was an equal sex distributionand most patients presented between theages of 30 and 50. Epilepsy was the most

common first symptom, sometimes of longduration (19 out of 42 cases). Half gave a--,history of less than twelve months dura-tion. Patients with a short history often hadraised intracranial pressure, or an oncom-ing neurological deficit. Twenty tumourswere frontal in position, nine temporal orfronto-temporal, and 13 more posteriorlysituated. Half the tumours were calcified atthe time of diagnosis. Mitotic activity was

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observed in most tumours (36 out of 42cases). Operation was performed in eachcase to establish the diagnosis. Eightpatients had a needle biopsy through aburrhole, three had an open biopsy atcraniotomy, 17 had a subtotal removal and14 had a macroscopic complete removal.Five cases had further operations, 31+patients had radiotherapy after initialtsurgery and five at a later date. The out-come was not as favourable as anticipated;eleven patients died within three months ofoperation and only ten patients survivedfive years. No specific clinical, operative or ,histological factors appear to predict thelength of survival.

STUDIES ON CEREBRAL FUNCTION ANDnmBLOOD-BRAIN BARRIER PERMEABILITY INPATIENTS WITH HYDROCEPHALUS ANDBENIGN INTRACRANIAL HYPERTENSIONUSING POSITRON EMISSION TOMOGRAPHYDJ Brooks, RP Beaney, KL Leenders,M Powell, A Crockard, DGT Thomas,A 4J Marshall, T Jones (London)The authors had used positron emission .,tomography to study cerebral oxygen util-isation and blood flow in patients with ,,,-acute obstructive hydrocephalus, withnormal pressure hydrocephalus or hyd- ,rocephalus secondary to congential lesions,or with benign intracranial hypertension.>,Patients with hydrocephalus due to allcauses showed a reduction in corticaloxygen utilisation and blood flow com-pared to normal controls, but thosepatients whose symptoms had been presentfor four months or less had a raised oxygenextraction, considered to be an indicationof a potentially reversible situation. Both,acute and chronic groups of hydrocephaluspatients were restudied after cerebraldecompression. The acute group showed asignificant increase in cortical blood flowand a fall in cortical oxygen extraction fol-lowing surgery, whereas little change wasfound in the cerebral metabolism in thechronic group. Patients with benign inter-4

,cranial hypertension and CSF pressures ofup to 58cm of water did not show



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Proceedings of Society of the British Neurological Surgeonssignificant changes in cerebral oxygen util-isation, blood flow or cerebral blood vol-~'iume. Blood-brain-barrier permeability wasassessed using 82Rb+, a K+ analogue, butwas not abnormal either in patients withbenign intracranial hypertension or in

'those acute obstructive hydrocephalus.Although clinical correlations were notreported, the authors suggested that araised oxygen extraction by cortical tissue,might indicate potentially reversible cere-bral dysfunction in hydrocephalus.Nevertheless only those patients with ashort history of symptoms were likely on-metabolic grounds to respond to cerebraldecompression.

- "ECIRCULATION FOLLOWING TEMPORARYCEREBRAL ISCHAEMIANV Todd, P Picozzi, HA Crockard,R Ross-Russell (London)

-Transient cerebral ischaemia is seen byneurologists as a result of spontaneousemboli from the cortid artery and byneurosurgeons as a result of temporary'ascular clipping during surgery for aneur-ysm and AVM. This study examined theeffect of increasing duration of ischaemiaon the level of blood flow during recircula-

.--tion. Global forebrain ischaemia was pro-duced in anaesthetised rats (Pulsinelli1979) by permanent occlusion of the ver-tebral artery followed by temporary carotidclamping, CBF was measured regionally byhydrogen clearance. Three groups of ratswere made ischaemic for 15, 30, or 60minutes (Groups A, B, C). During carotid

.-occlusion CBF fell in all rats, but therewere differences in the extent of reflow--between the three groups. On recirculationthere was a pronounced but short lastinghyperaemia which was most marked inGroup A, but most prolonged in group C.his was followed by a prolonged reduc-

tion in CBF (hypoperfusion) with flow- reduced most in Group A and least inGroup C. These differences were found at

-1, 2, and 3 hours of recirculation.

GroupDuration ofIschaemia (minutes)

Pre-occlusion blood flowIschaemic blood flowPeak hyperaemiaDuration of hyperaemia (min)rCBF at 60 mins reperfusion

p < 0-01 tp < 0-001

The authors concluded tperiods of temporary vasuLbe followed by an initialfinally by hypoperfusionreduction in flow (60% coning for many hours after r

CHRONIC SUBDURAL HAE?ELDERLY- SHOULD WE OPIRDE Battersby (SheffieldManagement of chrhaematoma in the elderly itroversy: are the presentinto the lesion or to longnervous system disorder?ment worthwhile? are moireferred? To answer thesauthor had studied 72 paween 60 and 90 years1957 and 1983. Thirty-eiglwere in the seventh deceighth and 15 in the ninthfold increase in referrals h;1975, with average age arfemales rising significantlyfor 2 years, or until full inachieved. Older patientsconfusion than raised intrias a presenting symptom.were equally distributed.injury was obtained in 67likely with increasing aginfluence duration of symlesion. In the seventh andfull recovery occurred in Egical mortality of 3-5%; infull recovery occurred inmortality was 47%. Six pational longstanding CNS difusion); five of these wereand none benefited from sioverall depended on apatients faring worst, butof presenting symptoms, nfusion or coma on admissi(80 often had symptoms attlongstanding CNS disordc

A15

B30

80 + 5 93 + 95-5 + 0-4 6-3 + 0-9256+ 13 186+ 20 ]16-9 + 0*5 21-9 + 1-3 t 644 + 6-5* 48 + 3.5

that even shortar clipping couldhyperaemia andwith a severetrol values) last-ecirculation.

MATOMA IN THEERATE?

-.A.)

599

dental subdural collection; below this agesymptoms tended to be more clearlydefined. It was concluded that surgeryshould be recommended in all patientsbelow 80 years and in all patients withraised intracranial pressure, but the authorcautioned that very elderly patients, espe-cially those with longstanding CNS disor-der, had a poor prospect of useful recovery.

onic subuurai A RETROSPECTIVE COMPARATIVE STUDY OFis subject to con- MEDICAL VERSUS SURGICAL MANAGEMENTig symptoms due OF GLIOMAS,standing central SJ Roe, GMcD Towns, DW Chadwick, PMis surgical treat- Foy, MDM Shaw, IR Williams (Liverpool)re patients being The doubts about the value of surgery forse questions the malignant gliomas had led to a great reluc-tients aged bet- tance on the part of the medical neurolog-treated between ists in Liverpool to refer patients for aht of the patients biopsy. The practices of two neurologistscade, 19 in the were compared with those of twoi decade. A four neurosurgeons, all of whom consideredas occurred since themselves to be conservative in theirnd porportion of management of gliomas. They reviewed' Follow up was retrospectively all CT scan reports for suchdependence was cases admitted under the care of the fourmore often had consultants over the 5 year period 1978 toacranial pressure 1982, and also the case notes of all patientsFocal symptoms whose CT scan report raised any possibilityA history of an of the diagnosis of a brain tumour were% and was more reviewed retrospectively. Those patients in;e. Age did not whom the diagnosis of a primary malignantiptoms or site of brain tumour was made on the basis of clin-I eighth decades ical and CT findings were included in theB9%, with a sur- study. Patients with proven primary malig-the ninth decade nancies elsewhere and multiple intra-only 27% and cerebral lesions were excluded. Two

atients had addi- hundred and eight patients were identifiedlisorders (eg con- but to July 1984 complete follow-up wasin their eighties achieved in 167 patients and these formedurgery. Outcome the basis of this preliminary report.ge, with older Patients were grouped according tonot on duration whether initial referral had been to aor on acute con- neurosurgeon (MDMS, PMF) or aon. Patients over neurologist (DWC, IRW). Comparisonributable to both revealed no differences with respect to age,er and a coinci- sex, clinical features including Glasgow

Coma Scale rating at the time of referral,C CT scan appearances, outcome on leaving60 hospital according to the Glasgow Out-come Scale and time of death or current

96 + follow-up. Neurologists and neuro-

5-8 ± 0*5 surgeons, having been referred similar167 15 patients, differed in the number of patients[67 selected for burrhole biopsy. In consequ-2. 1 ± 7 ence histological confirmation of the diag-82 ± 12-9t nosis was made less often in the neurologi-

cal patients, but analysis of the pathologicalfindings suggested that only theastrocytomas in the neurologically referred



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patients were not being biopsied. Youngpatients and those with cystic lesions weremore likely to be biopsed no matter towhom they were referred. Burrhole biopsywas associated with an increased early mor-tality and morbidity but there were a fewlong term survivors amongst those biop-sied. Referral to a neurologist or


neurosurgeon did not influence whether or quent management.not a patient underwent open biopsy withor without an internal decompression. Theauthors concluded that there are some The Norman Dott Memorial Lecture waspatients in whom there is little reasonable delivered during the meeting by Dr Paul '

doubt as to the diagnosis on clinical and CT Bucy, Chicago. The title of his address wasgrounds and in whom histological ""Scotland - The Birthplace of Surgicalconfirmation is not necessary for subse- Neurology".



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proceedings society british neurological surgeons · cerbral cortex. chronic stimulation of the...

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