While it is true that the natural course of the symptomatic aneurysm has not been established with certainty, the literature abounds with overwhelming evidence to indicate that an untreated aneurysm is a potentially explos-sive lesion associated with a high mortality rate and probably accounting for about 80 per cent of the cases of spontaneous subarachnoid hemorrhage at all ages.
Walton,29 in his very detailed monograph on subarachnoid hemorrhage, has made the most thorough review of the literature to date, and has also presented a complete study of 312 patients admitted over a 10-year period to the Royal Victoria Infirmary at Newcastle. The presence of aneurysms was verified in 63 cases and assumed in the majority of those cases of hemorrhage in which the cause was unknown. In a total of 1480 cases collected from 12 reported series, including the Newcastle group, the immediate mortality was approximately 45 per cent. Most of the deaths occurred during the initial hospital stay following subarachnoid hemorrhage. In Walton's series (Table 1), 91 patients died during the first attack and 47 more died of recurrent bleeding within 8 weeks, a total of 138 deaths. It is generally known and agreed that most immediate deaths from subarachnoid hemorrhage caused by a ruptured aneurysm usually occur during the first 24 hours; bleeding is especially likely to recur during the second and third weeks after the initial hemorrhage, with gradually decreasing incidence of further bleeding following this.
|47||recurrence in 8 weeks|
|20% of survivors (35 patients) died of recurrent hemorrhage, half of these within 6 months|
A later mortality from recurrent hemorrhage has also been reported, and in Walton's particular series, 20 per cent of the survivors (an additional 35 patients) died of recurrent hemorrhage within 6 months of the original hemorrhage. After 6 months, this author concluded that the risk of fatal recurrent bleeding was only 11 per cent; but, in addition, the number of disabling neurological deficits was significant. Thus, of 120 survivors, he found that 39 patients had moderate or severe sequelae and 5 were completely disabled. Magee20 traced 66 survivors from a group of 150 patients and found that 21 (14 per cent) were disabled and were unable to carry on normal lives.
Mount21 compiled a series of 752 conservatively treated cases of subarachnoid hemorrhage from many sources, including 130 of his own. He found that the average mortality rate was around 48 per cent. This should be compared with a 14 per cent mortality in 469 surgically treated cases, including 9 (11.7 per cent) of 77 in his own group. Small et al.27 also have drawn a comparison between the results of conservative and surgical treatment. In their series of 100 consecutive cases, 43 deaths occurred during the initial period of hospitalization, and only one-third of these patients died during the first 24 hours. Of the 57 survivors, 8 died of recurrent hemorrhage and 7 were totally disabled. Neurosurgical treatment is aimed not so much at saving those patients who died within a few hours of an overwhelming intracranial hemorrhage as it is in preventing the disastrous recurrence of bleeding. At the present time such treatment could be applied and would certainly be indicated in those patients who survived the first 24 to 48 hours after the initial hemorrhage. In 50 subsequent consecutive patients treated surgically, 16 had an intracerebral hemorrhage; the immediate surgical mortality was considered to be 12 per cent. Although 52 per cent of the survivors had some neurological disability, only 12 per cent were totally disabled.
McKissock and Walsh,19 in their series of conservatively treated cases of verified aneurysm, found a similar mortality rate of about 50 per cent. They have likewise attempted to assess the results of surgical treatment for purposes of comparison, making a detailed classification of cases according to the severity of hemorrhage and the site of the intracranial aneurysm. They graded the aneurysms in much the same way as malignant lesions would be graded, thereby presenting the most critical comparison yet to appear. In their series of 108 medically treated patients, 57 died (53 per cent). Thirtyeight of the 57 deaths were among patients in so-called category “A” which includes those in danger of immediate death from the hemorrhage for which they were hospitalized, and patients in coma or semicoma with neurological signs. Of 141 patients treated surgically, 47 or 33.3 per cent died, and 34 of the 47 patients who died were in category“A.”
It is generally accepted by neurosurgeons and neurologists that a high operative mortality is associated with the performance of any surgical procedure during the immediate period following a hemorrhage. The experience of Botterell3,4 and others with hypothermia and hypotension may in time reduce this mortality rate; however, present methods of treatment, for the most part, have been directed at the prevention of recurrent bleeding among the 70 per cent of patients who survive the initial hemorrhage and the prevention also of neurological disability caused by repeated bleeding. If these aims are accomplished, then surgical treatment could be judged as effective. With this goal in mind, a study has been made of the results of treatment of patients with intracranial aneurysms; these patients have had follow-up studies on the Lahey Clinic neurosurgical service for periods up to 20 years. A total of 277 patients has been studied, and in each case the presence of aneurysm was verified by arteriogram, at surgery or at postmortem examination. A further group of 36 patients has not been included because the follow-up period had not exceeded 1 year at the time of this writing.
One of us (J.L.P.)25 made a previous report of 101 patients in this group who were subjected to carotid ligation. Three immediate deaths and 8 subsequent deaths occurred, 2 of which were caused by recurrent hemorrhage from the treated aneurysm. At the time of that report, 40 patients had been subjected to craniotomy, resulting in the immediate death of 7 and the subsequent death of 3 patients. The reduction of mortality and morbidity by the use of controlled carotid ligation has subsequently been reported.7,8 The present report deals with the over-all results of the general methods of surgical treatment. It should be emphasized that the selection of the particular operative procedure has been determined chiefly by the location of the aneurysm, its severity and the presence or absence of intracerebral hematoma. Approximately 45 per cent of the patients in this series have had aneurysms arising from the intracranial portion of the internal carotid artery within the cavernous sinus, above the cavernous sinus of the vestigial type or at the bifurcation of the artery itself. In general, these aneurysms have been treated either by carotid ligation in the neck or by the “trapping” procedure with cervical carotid ligation followed by intracranial clipping of the internal carotid artery distal to the aneurysm. Nearly all of the patients discussed below who were subjected to carotid ligation have had internal carotid aneurysms.
In the group of patients subjected to craniotomy (except those in whom craniotomy was utilized to complete a trapping procedure) the intracranial aneurysms arose from the middle cerebral artery, the anterior cerebral-anterior communicating complex, and in a smaller number of cases from the posterior communicating, posterior cerebral and vertebral vessels. While some of these patients have also undergone carotid or vertebral ligation in addition to craniotomy, it has been felt that cervical ligation alone is inadequate in the treatment of these lesions.
When craniotomy has been employed for a direct attack upon an intracranial aneurysm, the general principles of surgery of intracranial aneurysms have been rigidly followed. If the aneurysm proved accessible to clipping or excision without compromising the parent vessel, this was carried out; if not, one of the several alternative procedures was employed. These include muscle wrapping or a combination of clipping and muscle wrapping, proximal clipping of a parent vessel such as the anterior cerebral artery, or intracranial trapping when this appeared feasible without compromising important elements of the cerebral circulation.
Fifty-one patients in this series were not treated surgically (Table 2). Some had refused operation and died of repeated hemorrhages although they had made a good recovery from the first episode of bleeding. Death was the result of the initial or repeated hemorrhage in 21 patients. Twelve of these died shortly after admission to the hospital, that is, within the first 24 to 48 hours, and 9 others died within several weeks of a further rupture. Seven patients died of recurrent hemorrhage between 3 months and 6 years after the initial hemorrhage. It should be noted that of the 19 survivors, only 2 are considered disabled and the others have been well from 1 to 12 years.
|Death from initial or repeated hemorrhage||21|
|Death from recurrent hemorrhage (3 mos.–6 yrs.)—includes 4 patients with 2 aneurysms||7|
|Died of other causes (1 yr.–12 yrs.)||4|
|Survivors (7 mos.–12 yrs.)—practically all are well; 2 patients are disabled||19|
Repeated emphasis on the increased risk of surgery during early periods after rupture of an aneurysm has been documented throughout the surgical literature by reports of very low surgical mortality with delayed operation as compared to early operation, and this tends to lend support to the arguments of those who would advise only conservative treatment. Norlén and Olivecrona24 operated on 15 patients in periods varying from a few hours up to 22 days after rupture of an aneurysm; 8 of these patients died, 6 recovered and 1 was hemiplegic. Of 63 patients who underwent direct intracranial operation 3 to 4 weeks after the hemorrhage, only 2 died and 2 others were left with significant mental disturbances. Graf12 found that among 35 patients subjected to “delayed” operation (after 14 days) 2 died, and of 17 patients who had an “early” operation, 13 died. Three patients in his series operated upon on the 14th day all died, and for this reason he proposed deferring operation for 3 weeks. Hamby's13 comprehensive monograph on intracranial aneurysms includes a series of 32 surgically treated patients of whom 16 died. This author subsequently reported on 51 patients, 38 of whom underwent craniotomy and 13 carotid ligation. Of 17 patients with acute intracerebral hematoma, only 1 survived operation, and of 12 patients who died after a direct attack upon the aneurysm, operation was performed within 11 days after the hemorrhage. Eleven patients who survived were operated on about 2 weeks or more after the hemorrhage.
In this series, no attempt has been made to present specific details concerning the patients operated on within the first few hours or days following hemorrhage. Recognizing that a significant surgical mortality occurs during the first few days, our deliberate aim has been to reduce the subsequent mortality occurring up to 8 weeks, and for this reason the patients have been classified as shown in Tables 3 and 4. It should be noted in Table 3 that carotid ligation was carried out in 58 of 101 cases within 8 weeks from the time of the initial hemorrhage and 41 of these operations were performed within 4 weeks. In those cases in which hemorrhage did not occur, ligation was carried out because of third nerve or other ocular palsies, intractable pain or carotid-cavernous fistula caused by rupture of a carotid aneurysm within the cavernous sinus. Table 4 shows that in 57 of 95 patients who underwent craniotomy, the operation was performed within 4 weeks of hemorrhage. In the 8 cases in which hemorrhage did not occur, operation was performed because of pain or neurological deficit.
|Single or multiple hemorrhages|
|1–4 weeks before ligation||41|
|4–8 weeks before ligation||17|
|Interval between hemorrhage and ligation more than 2 months||31|
|Single or multiple hemorrhage|
|1–4 weeks before craniotomy||57|
|4–8 weeks before craniotomy||18|
|Interval greater than 2 months||12|
Grateful acknowledgement is made to Dr. David LaFia and Dr. Publio Silva for their review of the mortality.
BotterellE. H.LougheedW. M.ScottJ. W.VandewaterS. L. Hypothermia, and interruption of carotid, or carotid and vertebral circulation, in the surgical management of intracranial aneurysms. J. Neurosurg.195613: 1–42.BotterellLougheedScottVandewaterJ. Neurosurg.13: 1–42.
Prepared by Dr. R. S. Allison (Belfast) and Dr. John F. Mullen (Chicago) from notes used by the late Cecil Calvert for a paper which he delivered to the Society of British Neurological Surgeons in 1954 at Belfast.