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The paper by Lafuente and Maurice-Williams on p 1680–1684 describes a well documented, consecutive, personal series of neurosurgically treated patients with aneurysmal sub-arachnoid haemorrhage, and it puts the finger on a sore spot.
Since the early 1960s, not more than two randomised controlled trials of surgical interventions in aneurysmal subarachnoid haemorrhage have been published. As a result, we are still not sure whether patients should be operated early, whether it would be safe enough to operate in the 4–10 day period when risks of ischaemia are high, and whether surgery in patients with a lowered level of consciousness should be postponed, or not. It was therefore virtually impossible to make a surgical management strategy that fits the risk profile of the individual patient and base it on firm evidence.
Before these questions concerning aneurysm surgery have been answered, the new therapeutic possibility of endovascular coiling is gaining acceptance. The International Subarachnoid Aneurysm Trial (ISAT),2 which compared endovascular treatment with aneurysm surgery in more than 2000 patients had several characteristics not seen often in neurosurgical trials: it was randomised, large, and pragmatic. Neurosurgeons with limited experience (at least 30 aneurysm treatment procedures) were allowed to participate. Such a pragmatic study provides pragmatic, global results and conclusions: 76% of the patients who underwent endovascular treatment were independent after 1 year, whereas 69% of the patients who were allocated to neurosurgical treatment were independent (difference: 7%, 95% confidence interval (CI): 3 to 11%). Interestingly, a similar difference was found in the proportions of patients who had no symptoms at all after treatment, suggesting that neuropsychological disturbances may be more common after neurosurgical treatment.
The ISAT results should be considered as preliminary, as long term follow up results are lacking. The low rate of rebleeding after 1 year of follow up (0.2%) in ISAT are reassuring, but who knows how endovascular coils will behave after 3, 5, or 10 years? Other questions remain to be answered with regard to timing of the procedure and to the shape, size, and site of aneurysms that will be more suitable for coiling than for surgery.
The results of Lafuente and Maurice Williams are impressive: overall mortality in their series is 17.1%, and the mortality in operated patients was 5 out of 190 (2.6%). Should these figures be taken at face value? There are at least four potential sources of error here. Firstly, the favourable baseline characteristics compared with population studies3 suggests referral selection, although its effects may be limited because surgery was late.4 Secondly, authorship bias, as reported by Rothwell in carotid endarterectomy, should be considered, but is probably not applicable.5 Thirdly, publication bias may play a role; would other experienced neurosurgeons with somewhat less favourable results also publish such a study? Fourthly, there is the role of chance itself, note that the 95% CI for surgical mortality ranges from 1 to 6%. Because of the above, and because prognostic factors in ISAT were less favourable, a direct comparison with the neurosurgical results in this study is not possible.
However, we all want to make evidence based treatment decisions for our aneurysm patients. We therefore need large randomised studies that compare treatment strategies. These studies should allow for detailed scrutiny of subgroups and types of treatment. Where multicentre randomised studies cannot provide this because of their inherent heterogeneity, we will have to resort to well described single centre and population based studies with long follow up. I would not be surprised if neurosurgery should remain the treatment of choice for a rather large subset of patients with aneurysmal SAH. Meanwhile, the challenge to neurosurgeons will be to use and preserve their common expertise. The standard for late surgery has been set.
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