An Analysis of the Results of Treatment of Ruptured Intracranial Aneurysms

Report of 772 Consecutive Cases

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In a previous report1 it was shown that the operative results of the treatment of ruptured intracranial aneurysms could not be proven to be definitely better than conservative measures when all factors influencing the mortality were taken into account. This conclusion was based upon a survey of only 261 verified intracranial aneurysms and it has been considered desirable to see whether the study of a much larger series of cases confirms this view. This present paper is based upon an analysis of 772 consecutive cases of intracranial aneurysms, 510 of which have been reported previously.1,

In a previous report1 it was shown that the operative results of the treatment of ruptured intracranial aneurysms could not be proven to be definitely better than conservative measures when all factors influencing the mortality were taken into account. This conclusion was based upon a survey of only 261 verified intracranial aneurysms and it has been considered desirable to see whether the study of a much larger series of cases confirms this view. This present paper is based upon an analysis of 772 consecutive cases of intracranial aneurysms, 510 of which have been reported previously.1,2 The additional patients were under the care of one of the authors (W.McK.) at the National Hospital, Queen's Square, or Hospital for Sick Children, Great Ormond Street, prior to December 31, 1956, or at the Neurosurgical Unit of St. George's Hospital between July 1 and December 31, 1956.

A review of the entire series shows that in 84 cases the aneurysm had not ruptured, whilst in 89 the lesion had not been revealed by angiography in our department (Table 1). Since angiographic localisation of the aneurysm is an essential prerequisite to definitive surgery these 173 cases must be excluded, leaving 599 for detailed analysis. Cases in which treatment was conservative must naturally fulfil the same criterion.


Intracranial aneurysms

Unruptured 84 24 28
Ruptured 688 306 44
 No angiogram 50 49 
 Aneurysm not shown by angiography 39 37 
 Aneurysm shown by angiography 599 220 37

The distribution of the 599 aneurysms in relation to the vessel of origin is shown in Table 2 which agrees closely with the distribution of all ruptured intracranial aneurysms however diagnosed.


Distribution of ruptured intracranial aneurysms shown by angiography

Site of AneurysmNumberPercentage
Anterior cerebral-anterior communicating 174 29
Internal carotid-posterior communicating 165 28
Middle cerebral 101 17
Bifurcation of internal carotid 51 8
Peripheral anterior cerebral 15 2
Posterior cerebral and vertebral system 19 3
Multiple 74 12
   Total 599 100

Since it is the long-term results of the operative procedures that is of the greatest interest, the analysis is made on the information available at the latest follow up. The period of observation varies from over 10 years to less than 6 months and is given in detail in Table 3. Only 2 per cent of patients were lost in follow up and 90 per cent of the remainder have been under observation for the whole of the time since their discharge.


Length of follow up of survivors

Length of Follow UpTreatment
Conservative (No. of Patients)Surgical (No. of Patients)  
Less than 6 mos. 1 8 
 6–12 mos. 8 31 
 1–2 yrs. 19 69 
 2–3 yrs. 13 64 
 3–4 yrs. 9 34 
 4–5 yrs. 8 23 
 5–10 yrs. 30 58 
10–11 yrs. 1 3 

In assessing the patients at the time of this review, patients in “full work” were those who had returned to their former employment or to one financially equivalent even though they may have shown some neurological deficit, the “partially disabled” were those working but in a lesser capacity than formerly, whilst the “totally disabled” were out of work. Some of these latter patients were severely disabled physically or mentally but there were a small number who, although apparently fit for work, refused to undertake it. Since this was probably because of a change in mental attitude following their haemorrhage it was right to consider them as totally disabled. All deaths were included irrespective of cause and time (Table 4).


Results of Treatment

Site of AneurysmConservative TreatmentOperative Treatment
TotalDeaths %Full WorkPart. Disabil.Total Disabil.Not KnownTotalDeaths %Full WorkPart. Disabil.Total Disabil.Not Known 
Anterior cerebral-anterior communicating62 32 (52%) 25 140112 46 (41%) 46 8 12 0 
Internal carotid-posterior communicating31 15 (48%) 15 001134 33 (25%) 72 13 11 5 
Middle cerebral16 8 (50%) 8 00085 27 (32%) 40 7 9 2 
Peripheral anterior cerebral3 2 (66%) 1 00012 2 (16%) 5 1 3 1 
Bifurcation of internal carotid7 3 (43%) 3 01044 18 (41%) 17 6 3 0 
Multiple aneurysms40 16 (40%) 15 54034 12(35%) 14 4 2 2 
Other sites11 5 (45%) 5 0018 1 (12%) 6 0 1 0 
   Total170 81 (47%) 72 692429 139 (33%) 200 39 41 10 

It is seen that the mortality in the conservatively treated group is higher than in the group operated upon, the percentage of conservatively treated patients who return to full work is lower, but that more of the surgically treated patients are partially or totally disabled. This may well be an expression of the ability of surgery to save the lives of some patients with brains severely damaged by their haemorrhage.

The lack of follow up in 2 conservatively treated and 10 surgically treated patients does not affect the comparison of mortality since if all these patients were considered as dead the difference in mortality would be the same.

Nor does the cause of death affect the comparison as 4 conservatively treated and 7 surgically treated patients died from causes not related to their aneurysm or to the operation, and if these are excluded from the mortality figures the difference between conservatively and surgically treated groups remains the same. Only the crude death rate, therefore, need be considered.

Table 4 also shows that the comparisons are similar when considered in relation to the site of the aneurysms.

Time of Death. Table 5 shows that 74 per cent of all deaths in the conservatively treated group occurred within 1 month of admission and 72 per cent of the total deaths in the surgical group within 1 month of operation. Eleven per cent of the conservatively treated and 7 per cent of the surgically treated patients who survived 6 months, died later.


Time of death of patients

TimeConservatively Treated (Time after Admission)Surgically Treated (Time after Operation)
Less than 1 mo.60 100 
1–6 mos.10 19 
6–12 mos.3 7 
1–2 yrs.3 4 
2–3 yrs.3 2 
3–4 yrs.1 3 
4–5 yrs.1 1 
5–8 yrs.0 3 

Cause of Death. Forty-one conservatively treated patients died from the effects of the haemorrhage requiring their admission to our unit, 36 from a recurrent haemorrhage and 4 from causes not related to their aneurysm (aortic stenosis and cardiac failure in 1, coronary thrombosis in 1 and cerebral atherosclerosis in 2).

Eighty surgically treated patients died from the effects of their haemorrhage or of the operation which was performed, 50 from a recurrent haemorrhage and 7 from causes not related to their aneurysm (cerebral atherosclerosis in 2, cancer in 2, bacterial endocarditis in 1, coronary thrombosis in 2) whilst the cause of death was not known in the other 2.

The 50 deaths from recurrent haemorrhage after operation (12 per cent) were studied further. Forty-five patients had a further haemorrhage after carotid ligation and 38 of these died. There is no doubt that the pathologist's interpretation of the age of the haemorrhage in some of these patients who died within a few days of their operation may have been incorrect, and that they died from infarction of the cerebral hemisphere. Thirteen patients had a further bleeding after a definitive craniotomy and 10 of these died (proximal anterior cerebral clip—6; muscle wrapping—2; clipping of aneurysm—1; trapping—1). Two of the 3 patients who had a further haemorrhage after simple aspiration of an intracerebral haematoma died.

Nature of Operation. Table 6 shows that 417 (97 per cent) of the operative procedures were ones which it was hoped would prevent further rupture of the aneurysm. Exploratory operations should be considered as surgical failures whilst the miscellaneous group, usually simple aspiration of a haematoma through a burr-hole, were more or less despairing measures to save the patient's life.


Nature of operation performed

No.Per Cent  
Carotid ligation266 74 28 
Definitive craniotomy151 57 38 
Other craniotomy5 4 80 
Other operation7 4 57 
   Total429 139 100 


In a retrospective analysis one must consider a number of factors that could be related to the mortality and could have influenced the selection of the patient for a particular form of treatment.

Mode of Onset of the Haemorrhage

If coma occurs at the onset of a subarachnoid haemorrhage the patient's prognosis is worse than it is in those in whom consciousness is not lost. Table 7 shows that this is certainly true for the cases under discussion and further that the conservatively treated patients have a higher mortality than those operated upon, but that this difference is small in those patients who did not lose consciousness at the onset. This higher mortality for the conservatively treated patients was also apparent in the figures for aneurysms at the different sites.


Mode of onset of haemorrhage

Condition of PatientConservatively TreatedSurgically Treated
Total DeathsTotalDeaths
No.Per CentNo.Per Cent   
Coma at onset121 6856286105 37
No coma at onset49 132714334 24

State of Consciousness on Admission or before Operation

The state of consciousness at the time of treatment may be more important than the mode of onset of the haemorrhage and in Table 8 it can be seen how this affected the results. It is obvious that the more consciousness has been affected the higher is the mortality, and that the mortality of conservatively treated patients is higher than the surgical mortality in each group.


State of consciousness on admission

Condition of PatientConservatively Treated (On Admission)Surgically Treated (Before Operation)
Total DeathsTotalDeaths
No.Per CentNo.Per Cent   
Unconscious27 269631 2581
Clouding of consciousness41 2356174 6940
Alert102 3231224 4520

Neurological Signs on Admission or before Operation

The same tendency is shown in Table 9, in which neurological signs are considered (hemiplegia, hemianaesthesia or hemianopia) and presumably the extent of these signs is some indication of the degree of cerebral damage from haemorrhage or ischaemia.


Neurological signs

FindingsConservatively TreatedSurgically Treated
Total DeathsTotalDeaths
No.Per CentNo.Per Cent   
Severe signs23208742 2867
Moderate signs833745214 7435
No signs642438173 3721

Interval after Haemorrhage

Many deaths occur in the first few days after a subarachnoid haemorrhage from a ruptured intracranial aneurysm so that the success of operations performed a week after the bleeding must be measured against the natural recovery rate in conservatively treated patients who have survived for 1 week. Table 10 shows this comparison and demonstrates that the mortality of conservatively treated patients is worse than the operative mortality only for the patients admitted or operated upon within 4 days of their haemorrhage, and that after this time neither method was obviously better. The mortality of all patients treated conservatively 4 or more days after the bleeding is 30 per cent and the operative mortality is 26 per cent.


Interval between haemorrhage and treatment

Length of IntervalConservatively TreatedSurgically Treated
Total  DeathsTotalDeaths
No.Per CentNo.Per Cent      
1 day 38 35 927337 51 
2 days 13 7 542713 48 
3 days 8 6 752411 46 
4–6 days 14 5 365520 36 
7–9 days 17 9 533413 38 
10–13 days 9 2 224814 29 
2–3 wks. 10 2 203711 30 
3–6 wks. 25 7 28585 9 
6–8 wks. 12 3 25263 12 
Over 8 wks. 24 5 214712 26 

Age of Patients

Table 11 shows the influence of age of the patient upon the results and again the mortality of conservatively treated patients is higher than that of the patients operated upon in the majority of the decades.


Age of patients

AgeConservatively TreatedSurgically Treated
Total DeathsTotalDeaths
No.Per CentNo.Per Cent   
10–19 yrs.4 1 2513 1 8 
20–29 yrs.8 4 5037 5 14 
30–39 yrs.16 2 1275 22 29 
40–49 yrs.53 22 42149 49 33 
50–59 yrs.53 28 53110 40 36 
60–69 yrs.28 19 6841 18 44 
70–79 yrs.8 5 633 3 100 
Unknown  1 1  

Blood Pressure

The hypertensive patient fares less well than the normotensive one (the upper limit of normal is taken as 160/90) and the surgical mortality is lower than the mortality of untreated patients in each group (Table 12).


Blood pressure

Blood PressureConservatively TreatedSurgically Treated
Total DeathsTotalDeaths
No.Per CentNo.Per Cent   


Some authors have said that the mortality from ruptured intracranial aneurysms is higher in females than in males but this is not borne out by our figures, which are given in Table 13.


Sex in relation to mortality

SexConservatively TreatedSurgically Treated
Total DeathsTotalDeaths
No.Per CentNo.Per Cent   
Males68 31461816234
Females102 50492487731

Selection of Patients for Surgery

Although our policy has been to operate upon the majority of patients with ruptured intracranial aneurysms it is obvious that a proportion must have been denied surgery for some reason—either by natural selection from death before operation could be performed or by some more positive selection on the part of the surgeon.

In Table 14 is shown the rate of operation in relation to some of the factors that were encountered. The average rate of operation was 71.5 percent and it may be seen that patients with multiple aneurysms and aneurysms of the anterior communicating artery, those unconscious on admission or those with severe neurological signs, those seen within 24 hours of their bleeding or after 8 weeks, and those over 50 years of age were less likely to come to operation than were the other patients. In some instances this can be explained. When multiple aneurysms are present it is sometimes impossible to decide which one has bled and so surgery cannot be undertaken. In the other examples the patient's poor general condition following the haemorrhage may well have been the reason for denying surgery.


Influence of clinical features upon rate of operability

FeatureTotal% Operated Upon
Anterior communicating aneurysm174 64 
Internal carotid-posterior communicating aneurysm165 81 
Middle cerebral aneurysm101 85 
Carotid-bifurcation aneurysm51 87 
Multiple aneurysms74 46 
Coma at onset407 70 
No coma at onset192 74 
Unconscious58 53 
Clouding of consciousness215 81 
Alert326 69 
Severe neurological signs65 65 
Moderate neurological signs307 73 
No abnormal signs237 73 
Haemorrhage—operation or admission interval  
 Less than 1 day111 65 
 2 days40 68 
 3 days32 75 
 4–6 days69 80 
 7–9 days51 67 
 10–13 days57 84 
 2–3 weeks47 79 
 3–6 weeks83 70 
 6–8 weeks38 68 
 More than 8 weeks71 66 
Under 50 years of age355 77 
Over 50 years of age243 64 
Normotensive326 72 
Hypertensive273 72 
One haemorrhage only348 69 
Two haemorrhages190 75 
More than 2 haemorrhages61 79 

High rates of operation occurred in patients with internal carotid-posterior communicating aneurysms or with middle cerebral aneurysms, those with only slight clouding of consciousness, those seen between 4 and 21 days of their bleeding, those under 50 years of age, and those who had three or more haemorrhages. Again some explanation may be offered. Aneurysms of the internal carotid artery were, in the main, treated by the simple operation of carotid ligation in the neck, carrying a low immediate mortality, and this operation was considered in all cases in which carotid compression in the neck was tolerated. Aneurysms of the middle cerebral artery were, for a time, treated by staged ligation of the common and internal carotid arteries in the neck and were readily operated upon. Patients who had more than one haemorrhage had been considered as candidates for surgery since our early days, which explained the increasing rate of operation after each recurrent haemorrhage. So far as the other factors were concerned it is apparent that the good condition of the patient may have played a part in selection for operation.

In Table 15 this selection for surgery is further elaborated.


Selection of patients for conservative treatment

ReasonNo. of PatientsDeaths
Moribund15 15 
Deteriorating14 14 
Severe neurological signs9 6 
Incomplete investigations1 1 
Complications of angiography2 2 
Further haemorrhage in hospital10 10 
   Total51 48 
Long interval—haemorrhage to admission3 1 
One haemorrhage only26 3 
Multiple aneurysms30 10 
Inadequate collateral circulation20 4 
Various other reasons38 15 
Refused operation2 0 
   Total119 33(27.8%) 


Moribund Patients

Fifteen patients were in extremis by the time their aneurysms had been localised and as none had an intracerebral haematoma it was thought that surgery did not offer the patient any chance of survival. All 15 died ultimately.

Deteriorating Patients

Fourteen patients, although not moribund on admission, were deteriorating rapidly and as none had an intracerebral clot it was again thought that surgery had nothing to offer them. All of these 14 patients died.

Angiographic Complications

Two patients deteriorated after angiography in a manner that suggested that the investigation itself may have been responsible and again surgery was not thought to offer any chance of survival. Both died ultimately.

Severe Neurological Signs

Four patients with severe hemiplegia and 5 with akinetic mutism were denied surgery since it was believed that operation would not improve their disability. Six of these patients died. Death is very usual in these groups because the inertia consequent upon their disability is often followed by pulmonary complications, wasting and the development of pressure sores from which recovery is unlikely.

Incomplete Investigations

One patient died before full angiographic investigation of his aneurysm had been completed.

Death from Recurrent Haemorrhage in Hospital

Ten patients died from a further haemorrhage in hospital, 5 certainly before a planned operation. The details of the other 5 do not enable any conclusion to be drawn regarding the method of treatment that was to have been adopted.

All the above factors are adverse from the point of view of the results in the untreated patients and, for a comparison with the surgically treated group these patients must be excluded, making the mortality of the untreated group 27.8 per cent.

The other factors in selection were more or less neutral but in some cases advantageous to the untreated group. A single subarachnoid haemorrhage in a patient in the untreated group is a factor that would improve the mortality figures since a further haemorrhage would have been followed by operation, unless death occurred very quickly. When considering this factor, therefore, it is admitted that 8 patients originally in this group were transferred to the surgical group following a further bleeding.

Multiple Aneurysms

Denial of surgery to these patients on the sole ground that the responsible aneurysm was not known was a very neutral form of selection and the mortality of this group must approximate the mortality of conservatively treated patients who are not moribund and in whom the aneurysm has been demonstrated by angiography.

Inadequate Collateral Circulation

The demonstration of this condition, particularly in patients with anterior cerebral-anterior communicating aneurysms, was also a reason for withholding operation and did not depend upon the neurological or general state of the patient.

Refusal to undergo operation is also a neutral factor in selection.

Miscellaneous Group

This includes patients denied surgery for reasons of age, hypertension, obesity, senility or associated diseases—conditions that were considered to increase the risk of any operation or anaesthetic and although a little adverse to the untreated group were not greatly so.

Some of these factors, of course, were present in the surgical group and Table 16 gives details of those who were moribund, deteriorating, severely disabled or in a state of akinetic mutism. It also shows that if these adverse cases are removed from the surgical group the mortality rate of the remainder is 28.4 per cent.


Surgical patients

Condition of PatientNo. of PatientsDeaths
Moribund and deteriorating 31 25 
Severe neurological signs 13 5 
    Total 44 30 
Remainder 385 109(28.4%) 


The surgeon must always be satisfied that his operations are producing better results than would be attained by other forms of treatment. Of course, when the mortality of a disease treated by medical or conservative measures is 100 per cent then any patient saved by surgery represents an improvement. That the natural history of patients with ruptured intracranial aneurysms carries a high mortality is certain but the actual figure is not known. Before the advent of angiography the diagnosis of aneurysm could be made only at operation (rarely) or at autopsy but after the introduction of cerebral angiography surgeons have felt compelled to operate in an attempt to lower the admittedly high mortality following medical measures. Whether surgical treatment is proving successful we are unable to say because we have no yardstick for comparison. In all reported series of surgically treated patients, a very highly selected group is compared with an unselected group of patients with subarachnoid haemorrhage treated medically and quite obviously the two groups are not comparable. In an earlier paper1 we pointed out that if one took into account the reasons for selection of patients for operation it was possible to get medical and surgical groups which were more nearly similar and that a comparison of mortality in these two groups failed to establish the superiority of surgical treatment. As this conclusion was based upon an analysis of the case records of only 261 patients it was considered desirable to carry out a similar analysis on a larger group.

As definitive surgery can be applied only when the diagnosis has been confirmed by angiography, all cases not so proven must be excluded, irrespective of the form of treatment. Comparing the gross results of the remainder it has been shown that surgical treatment apparently carries a better chance of survival. Only the long-term results are of real value in these cases and our follow up of 98 per cent of patients extends to 11 years. The few patients not seen since discharge from hospital and those that died from causes not related to their aneurysms do not affect any comparison of mortality in the two groups. Further the results show that a reasonable assessment of the effect of treatment can be made 6 months after the subarachnoid haemorrhage since, whether treatment was medical or surgical, the additional mortality after this time is small.

Simple analysis of the patients into groups depending upon their age, blood pressure, site of the aneurysm, mode of onset of haemorrhage and neurological state on admission still show an apparent improvement in mortality after surgery although with certain factors this improvement is not great. Unfortunately the division of patients into subgroups renders comparisons less valid as the numbers in the subgroups become smaller. This is obvious, for example, in those cases of aneurysms at the carotid bifurcation in which surgical treatment apparently is not better than medical treatment but of which 44 were surgical cases and only 7 were cases of conservative treatment. Those patients with multiple aneurysms may well have been treated conservatively if there was inadequate evidence to indicate which aneurysm had bled and there is no reason to suppose that the mortality of this group of patients is likely to differ from the whole group of patients with ruptured aneurysms. It is interesting, therefore, that in these patients the mortality in the surgically and conservatively treated groups is similar (35 per cent and 40 per cent respectively).

The most revealing analysis, however, is that in which the time interval between the haemorrhage and admission or operation is considered. It is well known that there is a high mortality in the first week after a subaracnoid haemorrhage and it is unsound to compare patients operated upon late with conservatively treated patients first seen within a few hours of the bleeding. Our tables show that for patients treated 4 or more days after the haemorrhage, the mortality in the conservatively treated group is not so very different from the operative mortality. Operations performed within 3 days of a haemorrhage still carry a lower mortality than medical treatment applied to patients seen within 3 days of the bleeding but this can also be explained.

The percentage of patients operated upon has been shown to be lower when there are adverse factors in the patient's clinical state, although this may well be ascribed to the exclusion of those dying before operation could be considered or carried out. The number operated upon is higher when a simple procedure is the operation of choice whereas it is lower in the group in which the best form of treatment appears to be a definitive craniotomy. That the surgeon's hand is sometimes forced is well shown by the increasing proportion of patients treated by operation for recurrent haemorrhage, yet we have not shown that the mortality differs whether the haemorrhage is the first or any subsequent one.

We feel that the clinical judgment of the surgeon must have entered into the decision to operate so we have investigated the reason for not operating upon some of the patients—some reasons were favourable to the surgical figures and others to the figures of conservative treatment but some were neutral factors. The medically treated group contained a large proportion of unfavourable cases, patients who were moribund and deteriorating, or with severe neurological disability as well as those who died before a planned operation. There were 51 such patients, of whom 48 died. Similarly severely disabled persons in the surgical group numbered 44, of whom 30 died.

The decision not to operate was sometimes based upon factors concerning the cerebral circulation suggesting inadequacy for the type of operation indicated, and presumably this factor did not affect the figures of the untreated group. Similarly patients with multiple aneurysms and those who refused operation or who were referred elsewhere for investigation of some other disorder might give us some idea of the natural course of patients with subarachnoid haemorrhage caused by ruptured intracranial aneurysms. There were 54 such patients, of whom 15 died (28 per cent). A further group were refused surgery for reasons that we would not consider adequate today but which were not related to their condition after the haemorrhage, such things for example as raised blood pressure, an age of over 60 years, the presence of a cardiac or pulmonary lesion—conditions which have often, in the past, been considered as likely to increase the risks of anaesthesia. Such factors cannot be considered separately but should be considered in the total picture of the treatment of aneurysms.

Two other reasons for denying surgery favoured the figures of conservative treatment, a long interval between the haemorrhage and admission on the one hand and the occurrence of but one subarachnoid haemorrhage on the other, this latter point being a common reason for denying the patients surgery in the earlier cases of our series. If we consider only those patients who were treated conservatively for other than adverse reasons we have a group of 119 patients, of whom 33 died (27.8 per cent). This is almost identical with the surgical mortality excluding similarly unfavourable patients, 385 patients, of whom 109 died (28.4 per cent).

There remain to be considered those patients excluded from the above comparison, 51 medically treated with 48 deaths (94 per cent) and 44 surgically treated with 30 deaths (68 per cent), and it would seem that in this group surgery does have something to offer. It must be emphasised, however, that the good results are invariably associated with the evacuation of a compressing intracerebral haematoma (usually with a definitive attack upon the aneurysm), following which many patients improve dramatically. If, on the other hand, no haematoma is present then the mortality for surgical attack upon the aneurysm is as high as the mortality for conservative treatment.


We can come to one conclusion only—that there is no proof that the surgical treatment of ruptured intracranial aneurysms has effectively lowered the mortality unless a large haematoma is present and can be evacuated. This conclusion is based upon a retrospective analysis, which is always suspect and remains to be confirmed or refuted by analysis of a properly planned prospective trial of surgical and conservative measures. On the inconclusive results of our analysis of this large series of cases there can be no ethical reason why such a planned trial should not be carried out with the single proviso that patients shown to harbour a large intracerebral haematoma should be excluded from such a trial and given the benefit of immediate surgical treatment.


Analysis is made of 599 angiographically verified ruptured intracranial aneurysms with respect to the various factors related to the mortality.

It is shown that although surgical treatment appears to benefit these patients when only gross mortality figures are considered, it can be readily demonstrated that this is because of selection of the better patients for surgery and that if more nearly similar groups can be obtained the mortality of conservatively treated patients approximates the surgical mortality.

In the group of patients who are moribund or rapidly deteriorating the angiographic demonstration of a large intracerebral haematoma is an indication for immediate operation to evacuate the clot and, if possible, to deal with the aneurysm radically. If, however, no intracranial haematoma is present then the patient's chances of recovery are as good with or without surgery.

This conclusion must be tested by a correctly planned clinical trial of the two methods of treatment and such a trial is now in progress, 236 patients having satisfied the criteria for admission to the series.


  • 1.

    McKissockW.PaineK.WalshL. Further observations on subarachnoid haemorrhage. J. Neurol. Neurosurg. Psychial.1958n.s. 21: 239248.McKissockPaineWalshJ. Neurol. Neurosurg. Psychial.21: 239–248.

  • 2.

    McKissockW.WalshL. Subarachnoid haemorrhage due to intracranial aneurysms. Results of treatment of 249 verified cases. Brit J. med.19562: 559565.McKissockWalshBrit J. med.2: 559–565.

The material for this paper was collected and analysed during the tenure of a Research Fellowship awarded by The Board of Governors of St. George's Hospital, to whom our thanks are due.

Article Information

Present address: Department of Neurosurgery, University Hospital, Saskatoon, Saskatchewan, Canada.

© AANS, except where prohibited by US copyright law.




McKissockW.PaineK.WalshL. Further observations on subarachnoid haemorrhage. J. Neurol. Neurosurg. Psychial.1958n.s. 21: 239248.McKissockPaineWalshJ. Neurol. Neurosurg. Psychial.21: 239–248.


McKissockW.WalshL. Subarachnoid haemorrhage due to intracranial aneurysms. Results of treatment of 249 verified cases. Brit J. med.19562: 559565.McKissockWalshBrit J. med.2: 559–565.


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