Current management of cerebral aneurysms: is it based on facts or myths?

Controversies in the anesthetic management of intraoperative rupture of intracranial aneurysm

Despite great advancements in the management of aneurysmal subarachnoid hemorrhage (SAH), outcomes following SAH rupture have remained relatively unchanged. In addition, little data exists to guide the anesthetic management of intraoperative aneurysm rupture (IAR), though intraoperative management may have a significant effect on overall neurological outcomes. This review highlights the various controversies related to different anesthetic management related to aneurysm rupture. The first controversy relates to management of preexisting factors that affect risk of IAR. The second controversy relates to diagnostic techniques, particularly neurophysiological monitoring. The third controversy pertains to hemodynamic goals. The neuroprotective effects of various factors, including hypothermia, various anesthetic/pharmacologic agents, and burst suppression, remain poorly understood and have yet to be further elucidated. Different management strategies for IAR during aneurysmal clipping versus coiling also need further attention.

Thiopental and desflurane treatment for brain protection

OBJECTIVE

Thiopental produces cerebral metabolic depression and cerebral vasoconstriction. However, the effect of thiopental on brain tissue oxygen pressure (PO2), carbon dioxide pressure, and pH is not known. In a prospective study, we measured brain tissue gases and pH during thiopental or desflurane treatment that was administered for brain protection during brain artery occlusion.

METHODS

After institutional review board approval, 20 patients undergoing craniotomies for cerebrovascular surgery were tested; 10 were randomized to receive thiopental and 10 to receive desflurane. After each craniotomy, a Neurotrend probe (Diametrics Medical, Minneapolis, MN) was inserted to measure tissue PO2, carbon dioxide pressure, and pH in a tissue region at risk to develop ischemia during temporary brain artery occlusion. Thiopental or desflurane was administered to produce burst suppression of electroencephalography, and then temporary artery occlusion was performed during aneurysm or extracerebral-to-intracerebral bypass surgery.

RESULTS

Thiopental produced no change in tissue gases or pH, but temporary artery clipping in thiopental-treated patients decreased PO2 30% (P < 0.05). Desflurane increased PO2 70% (P < 0.05), and tissue oxygenation remained elevated during temporary artery occlusion. Tissue pH did not decrease in either group during temporary brain artery occlusion.

CONCLUSION

Thiopental has a metabolically neutral effect on brain tissue gases and pH, even though it is known to decrease cerebral oxygen consumption. The metabolic depressant and vasodilator effects of desflurane enhance tissue oxygenation and attenuate tissue PO2 reductions produced by artery occlusion. Both thiopental and desflurane inhibit ischemic lactic acidosis and decreases in pH.

Risk of harboring an unruptured intracranial aneurysm

BACKGROUND AND PURPOSE

The purpose of the present study was to calculate the prevalence and relative risk of unruptured incidental intracranial aneurysms (IAs) among families with IA case(s) compared with the general population in one geographically defined area in East Finland and to identify the risk group that could benefit most from screening for IAs. We compared these results with our earlier study results of familial IA (FIA) cases, with two or more known IA cases in the same family.

METHODS

The study groups were collected from the catchment area of the University Hospital of Kuopio in East Finland. The inclusion criteria were age 30 to 70 years and unruptured incidental IAs > or =3 mm. Patients with previous subarachnoid hemorrhage or in whom a ruptured IA was found to be the cause of death were excluded from all study groups. During routine forensic autopsies the circle of Willis was studied for IAs to estimate the number of IAs in the general population. In the families with one known IA case and in FIA families, MR angiography was used as a preliminary screening method for IAs, followed by intra-arterial angiography to verify suspected IAs. Study populations were age and sex adjusted for the statistical calculations.

RESULTS

The relative risk for IAs among first-degree relatives in FIA families was 4.2 (95% confidence interval, 2.2 to 8.0) and among first-degree relatives in families with only one affected family member was 1.8 (95% confidence interval, 0.7 to 4.8) compared with the general population in East Finland.

CONCLUSIONS

First-degree relatives in FIA families constitute a high-risk group for incidental IAs, and this group would benefit from screening studies for IAs. Screening for IAs in families with only one affected member or in the general population is not recommended.

Cerebral aneurysms: analysis of rehabilitation outcomes

OBJECTIVE

To classify deficits after aneurysmal subarachnoid hemorrhage (SAH) and correlate rehabilitation outcomes with these findings.

DESIGN

A retrospective review of medical records.

SETTING

Institution-based rehabilitation hospital.

PARTICIPANTS

Eighty patients admitted to a rehabilitation facility after aneurysmal SAH.

MAIN OUTCOME MEASURES

For each subject, data were collected for time between surgery and admission, total inpatient days, time orientation at discharge, and level of supervision required at discharge.

RESULTS

Fifty-five percent of the subjects were women and 45% were men. The average age was 47 years. Sixty percent of the lesions were right-sided and 40% were left-sided. Aneurysms were localized, in decreasing order of frequency, in the anterior communicating artery, middle cerebral artery, posterior communicating artery, internal carotid artery, basilar artery, anterior cerebral artery, and posterior inferior cerebellar artery distribution.

CONCLUSION

Longer rehabilitation stays were associated with right-sided lesions (mean = 44.64 versus 33.93 days) and motor impairment (mean = 43.8 versus 31.53 days). A trend suggested that motor impairment also predicted the level of supervision required at discharge. The shorter the time between surgery and admission to rehabilitation, the more likely the patient will be oriented at the time of discharge (29.47 versus 43.29 days).

Temporary vessel occlusion during intracranial aneurysm repair

Any method that decreases the risk of intraoperative rupture should improve outcome if complications associated with its use do not negate positive effect. If application time is limited and a form of cerebral protection and appropriate monitoring of cerebral function are used, temporary clip application may meet these requirements. The efficacy of temporary occlusion as an adjunct to aneurysm clipping may be limited by technical considerations with respect to regional anatomy, aneurysm size, and aneurysm consistency. In areas of limited access, positioning proximal clips may not be feasible. The use of endovascular techniques of balloon occlusion may provide proximal control in these situations (9, 106). The decision to use total circulatory arrest and profound hypothermia, as opposed to temporary clip application, remains largely a matter of the surgeon's judgment. The role of proximal parent vessel ligation must also be considered in the decision-making process regarding the treatment of giant or technically difficult aneurysms (114). Further refinements in cerebral monitoring that can accurately reflect intracellular processes in all territories affected by the application of temporary clips or balloon occlusion and development of more effective forms of cerebral protection may permit safer use of this technique. An adequately controlled clinical trial of temporary occlusion with or without putative "cerebral protection" is needed to confirm the efficacy of this technique.

Which are the major determinants for outcome in aneurysmal subarachnoid hemorrhage? A prospective total management study from a strictly unselected series

In this prospective study we report the outcome for all patients with a verified aneurysmal SAH managed at the Department of Neurosurgery at the University Hospital in Lund, Sweden during the four-year span from June 1, 1989 to May 31, 1993. A total of 275 patients were admitted during the study period. The vast majority of patients (196 individuals, i.e. 71%) was admitted within 24 h after the bleed. Mean age was 54.3 years and the female/male ratio 1.8/1. Nimodipine was administered in 231 (84%) of the 275 patients. We clipped the ruptured aneurysm in 199 patients. At follow-up 3 months after the bleed 161 patients were classified as having made a good neurological recovery (59%). The morbidity was 20% and 59 patients (21%) had died. The overwhelming cause for morbidity and mortality was damage from the initial bleed (62 patients, 23%). Notably, considering morbidity and mortality, delayed ischemia was less frequent than both surgical complications and rebleeding, respectively. Of the 275 patients, 13 (5%) patients made an unfavorable outcome due to delayed ischemic deterioration. There was a strict correlation between the initial clinical condition and final outcome. Of 51 grade V patients, only 2 made a good recovery. There was also a strict correlation between the amount of extravasated blood and outcome. There was no difference in clinical outcome between patients with arterial hypertension versus normotensive individuals. The mortality rate was worse for posterior circulation aneurysms.(ABSTRACT TRUNCATED AT 250 WORDS)

Traumatic intracranial aneurysms in childhood and adolescence. Case reports and review of the literature

We report four pediatric traumatic intracranial aneurysms occurring before the age of 10 years. Two of these aneurysms were the result of closed head injury. The remaining two were iatrogenic aneurysms which occurred in unusual circumstances. These four children represent 33% of the pediatric intracranial aneurysms seen at the Children's Hospital of Eastern Ontario from 1974 to 1992. Diagnosis of traumatic intracranial aneurysms requires a high index of suspicion: any head-injured or postoperative child who experiences delayed neurologic deterioration, or who fails to improve as expected following treatment, should promptly undergo diagnostic intracranial imaging. Documented subarachnoid hemorrhage, intracerebral or intraventricular hemorrhage, or subdural haematoma in this clinical setting should be further investigated by cerebral angiography to exclude a traumatic aneurysm or other vascular lesion. Traumatic aneurysms typically arise at the skull base or from distal anterior or middle cerebral arteries or branches consequent to direct mural injury or to acceleration-induced shear. Reported traumatic aneurysms account for 14%-39% of all pediatric aneurysms. Iatrogenic aneurysms also occur with unexpected frequency during childhood and adolescence. Pediatric traumatic cerebral aneurysms may present early or late. Most present early with intracranial hemorrhage. Late presentation occurs infrequently, typically as an aneurysmal mass. Once diagnosed, these aneurysms should be promptly treated by craniotomy employing routine microsurgical techniques, or in some cases, by endovascular detachable balloon techniques. Delay in operative treatment entails significant risks of repeated hemorrhage and death. Outcome in these children is primarily determined by the extent of traumatic cerebral injury and the preoperative clinical status. The latter directly depends upon diagnosis of the aneurysm prior to either initial or repeated hemorrhage.

Long-term outcome of surgically treated unruptured cerebral aneurysms

We report the surgical morbidity and mortality and the results of statistical analysis based on the long-term outcome (average 50.1 months) of 69 patients with unruptured cerebral aneurysms. These patients harbored a total of 76 unruptured cerebral aneurysms, 72 larger than 3 mm in diameter. All the latter were surgically treated. There was no operative mortality. Operative morbidity occurred in 5 patients (7.2%), including hemiplegia in 2 from obliteration of perforator vessels, transient memory impairment in 2 due to brain retraction, and transient oculomotor nerve palsy in 1 patient resulting from an unknown etiology. During the observation period, 53 patients (76.8%) had a good or fair outcome, 11 (15.9%) had a poor outcome, and 5 (7.3%) died from causes unrelated to the aneurysms, such as pneumonia, gastrointestinal bleeding, and heart failure. The 5-year survival rate was 94%. Statistical analysis of the long-term outcome of all patients showed no significantly important factor influencing long-term morbidity. Prophylactic surgery of aneurysm is recommended for low-risk patients who may develop eventual rupture of an aneurysm, but perforator vessels around the aneurysm should be preserved, clips should be properly placed, and brain retraction should be minimized.

Aneurysmal bleeding. A plea for early surgery in good-risk patients

From 1985 onwards we have aimed at operating on good-risk patients, i.e., those graded I-III on the WFNS SAH Scale, within 3 days after the aneurysmal bleed. We report on a series of 100 consecutive operations for saccular aneurysm, covering a period of 5 1/2 years. Early operations (in the above sense) were done in 57 good-risk but otherwise unselected patients. After a one year follow-up, 47 of them (82%) were found to have made a good recovery (Glasgow Outcome Score I). The outcome of (mostly early) surgery in 15 selected poor-risk patients (WFNS SAH Scale IV and V) was much less favourable. Late surgery (4 or more days after SAH) was performed in 28 good-risk patients, most of whom had been admitted several days or weeks after the bleeding. Almost all of these patients had a good outcome. It is argued that the known management results of delayed surgery, which during the deliberately chosen interval exposes the patient to the risk of rebleeding and vasospasm, have by now been surpassed by those of early surgery. However excellent the surgical results of delayed operations may be, early operation should become the treatment of choice in good-risk patients.

Management results attained by predominantly late surgery for intracranial aneurysms

In contrast to previous studies conducted by various authors, who recommended early surgery for all patients admitted to the hospital within 72 hours of an aneurysmal subarachnoid hemorrhage, several more recent studies have declined to advise early surgery for the treatment of patients with impaired consciousness. In our series, early surgery was undertaken for patients who were rated at Grades 1 to 2 (Hunt and Hess) at admission and who did not exhibit any additional risk factors (e.g., evidence of incipient vasospasm, giant aneurysm, unfavorable aneurysm location, or a severe concomitant disease). Only three patients rated Grade 3 at admission with a favorable aneurysm location and shape underwent early surgery. The management results attained in this series (n = 131), in which the early surgery rate was 17%, have been analyzed. The management mortality rate of patients with aneurysmal subarachnoid hemorrhage was 13%, and it was 7.7% for patients admitted at Grades 1 to 3 on the Hunt and Hess scale. Good results (Glasgow Outcome Scale, 1 or 2) were attained in 75% of the entire study population, in 85% of patients admitted at Grades 1 to 3, and in 53% of those patients who were admitted at Grades 4 to 5 and who underwent late surgery after their condition had improved to Grades 1 to 3. At an average interval of 3 years after the operation, 83% of the patients discharged with Glasgow Outcome Scale ratings of 1 or 2 reported no significant restriction of their "stress resistance."(ABSTRACT TRUNCATED AT 250 WORDS)

Permissible temporary occlusion time in aneurysm surgery as evaluated by evoked potential monitoring

To clarify the permissible time for temporary vascular occlusion during aneurysm surgery, we have undertaken a retrospective analysis of the results of intraoperative median nerve somatosensory evoked potential (SEP) monitoring in 97 patients with middle cerebral artery (MCA) (46 patients) or internal carotid artery (ICA) (51 patients) aneurysms. All patients underwent temporary vascular occlusion, lasting from 2 to 70 minutes, under the administration of a mixed solution of 20% mannitol with phenytoin and vitamin E. The mean occlusion time was 20.3 minutes for the MCA patients and 15.8 minutes for the ICA patients. The SEP disappeared during occlusion in 42 patients (30 MCA and 12 ICA). All but three eventually recovered the SEP to the baseline level after recirculation, and none of the 39 patients had postoperative sequelae. The time period from the start of occlusion until the complete loss of the SEP averaged 8.6 minutes among these 39 patients, and the occlusion time from total SEP loss until recirculation averaged 12 minutes. In the remaining 3 of the 42 patients (all 3 being ICA aneurysm patients), however, the SEP did not recover after recirculation and all 3 patients showed postoperative sequelae. In two of these three patients, vascular occlusions were performed at the multiple sites (i.e., at the ICA, MCA, anterior cerebral artery, and posterior communicating artery) and the SEP disappeared rapidly after the occlusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Vasodilators during cerebral aneurysm surgery

The objective of this review is to review the anaesthetic implications of vasoactive compounds particularly with regard to the cerebral circulation and their clinical importance for the practicing anaesthetist. Material was selected on the basis of validity and application to clinical practice and animal studies were selected only if human studies were lacking. Hypotensive drugs have been used to induce hypotension and in the treatment of intraoperative hypertension during cerebral aneurysm surgery. After subarachnoid haemorrhage, cerebral blood flow is reduced and cerebral vasoreactivity is disturbed which may lead to brain ischaemia. Also, cerebral arterial vasospasm decreases cerebral blood flow, and may lead to delayed ischaemic brain damage which is a major problem after subarachnoid haemorrhage. Recently, the use of induced hypotension has decreased although it is still useful in patients with intraoperative aneurysm rupture, giant cerebral aneurysm, fragile aneurysms and multiple cerebral aneurysms. In this review, a variety of vasodilating agents, prostaglandin E1, sodium nitroprusside, nitroglycerin, trimetaphan, adenosine, calcium antagonists, and inhalational anaesthetics, are discussed for their clinical usefulness. Sodium nitroprusside, nitroglycerin and isoflurane are the drugs of choice for induced hypotension. Prostaglandin E1, nicardipine and nitroglycerin have the advantage that they do not alter carbon dioxide reactivity. Local cerebral blood flow is increased with nitroglycerin, decreased with trimetaphan and unchanged with prostaglandin E1. Intraoperative hypertension is a dangerous complication occurring during cerebral aneurysm surgery, but its treatment in association with subarachnoid haemorrhage is complicated in cases of cerebral arterial vasospasm because fluctuations in cerebral blood flow may be exacerbated. Hypertension should be treated immediately to reduce the risk of rebleeding and intraoperative aneurysmal rupture and the choice of drugs is discussed. Although the use of induced hypotension has declined, the control of arterial blood pressure with vasoactive drugs to reduce the risk of intraoperative cerebral aneurysm rupture is a useful technique. Intraoperative hypertension should be treated immediately but the cerebral vascular effects of each vasodilator should be understood before their use as hypotensive agents.

Cerebral hemodynamics in subarachnoid hemorrhage evaluated by transcranial Doppler sonography. Part 1. Reliability of flow velocities in clinical management

During recent years, the management of subarachnoid hemorrhage (SAH) has changed, resulting in an increase in early operations and routine administration of nimodipine. Both influenced the indication for transcranial Doppler sonography (TCD). Furthermore, investigations detected discrepancies between Doppler findings and neurological status. In a prospective study, the reliability of TCD was investigated in patients with SAH treated with intravenously administered nimodipine. Patients with large hematomas were excluded. Neurological deficits immediately after surgery or within the first 48 hours were classified as not delayed, and therefore not necessarily due to vasospasm. The most remarkable points of this study are that there is no significant difference between the flow velocities for Hunt and Hess Grades I and II when compared with those for Grade III, and that Grades IV and V seem to be affiliated with the lowest velocities. When the flow velocities of 11 patients who developed delayed ischemic deficits (DIDs) were compared with those of patients with no deficit, no significant difference was seen. A significant increase in velocity in the days before the onset of DID was found only in 3 of 11 cases. Eight patients showed either constant high or constant low velocities or even, in some cases, decreasing time courses. High flow velocities did not necessarily mean impending neurological deficits: 8 of 66 patients tolerated flow velocities over 200 cm/s. Therefore, it no longer seems to be justified to proclaim that TCD is able to predict neurological deficits, although it is doubtless able to detect vasospasm.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral protection during aneurysm surgery with isoflurane anesthesia. Technical note

A strategy for intraoperative cerebral protection is described in which intraoperative electroencephalography is used to titrate the level of inspired isoflurane given for anesthesia to obtain isoelectricity prior to temporary vessel occlusion during repair of difficult aneurysms. During temporary vessel occlusion, arterial blood pressure is maintained or increased with an inotropic or vasopressor agent. After clipping of the aneurysm, the concentration of isoflurane is reduced to allow the patient to awaken in the operating room for early postoperative neurological examination. The combination of a high concentration of isoflurane, temporary vessel occlusion, and maintenance of arterial blood pressure may be a useful protective regimen during neurovascular procedures.

Haemodynamic considerations in the management of patients with subarachnoid haemorrhage

Cerebral vasospasm occurs, following subarachnoid haemorrhage, in the majority of patients and is accompanied by cerebral ischaemia in 30%. The objectives of this article are to review (1) the effects of subarachnoid haemorrhage and vasospasm on cerebral blood flow (CBF); (2) the effects of induced hypotension and hypocapnia on CBF in these patients; (3) current therapy for cerebral ischaemia from vasospasm. The medical literature was searched using Index Medicus; for the period 1983-90 this search was done on a computer with the CD-ROM version of Index Medicus, Silver Platter. Papers were selected on the basis of validity and applicability to clinical practice; animal studies are included when human data is lacking. Cerebral vasospasm may decrease cerebral blood flow, disturb autoregulation and place the patient at risk for delayed cerebral ischaemia. Intraoperative induced hypotension and hypocapnia can decrease CBF further, although effects of either on outcome have not been evaluated. Calcium antagonists are effective for both the prevention and the treatment of delayed cerebral ischaemia. Of the mechanical treatments, systemic-arterial hypertension has the firmest scientific foundation, although this is frequently combined with haemodilution and blood volume expansion. There is a need for randomized clinical trials to assess the efficacy of these latter treatments.

Perioperative management and outcome after surgical treatment of anterior cerebral artery aneurysms

The authors present clinical experience with 28 cases of ruptured anterior cerebral artery (ACA) aneurysms managed personally during a 36 month period, and 10 unruptured ACA aneurysms. The cases included five giant aneurysms and four distal ACA aneurysms. Management strategy was uniform and included early operative intervention (except in the setting of deteriorating neurologic deficit, not attributable to hydrocephalus or hematoma), and vasospasm prophylaxis including calcium channel blockers and hypervolemic hemodilution and arterial hypertension. Modern diagnostic adjuncts including transcranial doppler were used as they became available. Good outcome (outcome grade 1 or 2) was observed at 6 months in 71% (20/28) of ruptured cases and in 90% (9/10) of unruptured cases; fair outcome (outcome grade 3) was observed in 14% (4/28) of ruptured cases and in 10% of unruptured cases; bad outcome (outcome grade 4 or 5) was observed in 14% (4/28) of ruptured cases. There were no instances of rebleeding after admission to the hospital. There was a single mortality in a patient moribund on admission. Delayed ischemic deterioration (DID) was documented in 46% (13 of 28) of the ruptured cases, and was a major source of morbidity in 7 of the 9 instances of fair or poor outcome in the series. Management outcome, including the occurrence of subtle neuropsychological difficulties commonly described in cases with ACA aneurysms, is discussed with relation to the incidence of DID, the clinical course of DID, and the possible impact of various therapeutic strategies.

The effect of very early cisternal irrigation on basilar artery spasm after SAH in the rat model

The authors have investigated the effect of very early irrigation of the cerebrospinal fluid (CSF) space in the haemorrhage rat model of vasospasm. Fifteen rats had basilar cistern irrigation with physiological saline for 3 hours after subarachnoid haemorrhage (SAH), and fifteen control rats had subarachnoid haemorrhage without irrigation of clot. The changes in basilar arteries diameters were determined by angiograms obtained from the rats. The post haemorrhage angiograms showed significant basilar artery spasm in both groups (P less than or equal to 0.0005, t-test). However in the last angiogram the basilar artery diameter was found to have the same value measured before subarachnoid haemorrhage in the irrigation group whereas no obvious change was observed in the control group. In the irrigation group the mean diameter of the basilar artery in the last angiogram was 0.412 mm. (0.30 mm to 0.50 mm). None of the animals, treated by cisternal irrigation, showed angiographic vasospasm while the latter group did (P less than or equal to 0.0005). Animals treated with physiological saline irrigation had a median clot grade of 0.40 (range grade 0 to 2); control rats had a median grade 2.86 (range grade 1 to 4, P less than 0.001, Mann-Withney U test), on the brain stem, indicating significant reduction of clot by lavage. In conclusion, performance of experimental physiological saline irrigation at a very early time after subarachnoid haemorrhage prevents the arteriographic and morphological changes of both acute and late vasospasms.

One-session operation via bilateral craniotomies for multiple aneurysms after subarachnoid haemorrhage

One-session bilateral craniotomies for radical clipping of multiple aneurysms have been performed in 14 patients after subarachnoid haemorrhage. Bilateral small or medium sized aneurysms in pre-operatively good-grade Hunt and Hess (HH)I-III) patients (nine cases) were clipped without mortality or morbidity. Four poor-grade patients (HH IV at admission, improving to HH III pre-operatively) were treated, with unfavourable outcome in one patient. Another poor-grade patient (HH IV at surgery) with bilateral large middle cerebral artery aneurysms, a large intracerebral haematoma and a pontine angle meningioma survived with dysphasia and short-memory dysfunction. A slack brain at surgery and a short operation time justify one-session bilateral craniotomies also in the early post-bleeding period.

Surgical approach to a large basilar artery bifurcation and upper basilar trunk aneurysm: case report

The authors report a double aneurysm of the basilar artery located at the basilar artery bifurcation and upper basilar artery trunk between the posterior cerebral artery and the superior cerebellar artery. Clinical presentation, neuroradiological findings, surgical approach, and the operative technique are described and discussed.

Emergency surgery for haematoma-forming aneurysmal haemorrhage

Patients with intracerebral haematomas (ICH) secondary to aneurysmal bleeds usually have a poor prognosis or die if treated conservatively. Younger patients with rupture of a middle cerebral artery (MCA) aneurysm and temporal haematomas have the potential to return to useful life. They should be assessed separately from other subarachnoid haemorrhage (SAH) patients and considered for emergency surgery. Seven such cases are presented, five made an acceptable recovery. The experience of other units as represented in the literature is considered.

Ultrastructural changes of the basilar artery following experimental subarachnoid haemorrhage. A morphological study on the pathogenesis of delayed cerebral vasospasm

Recent experimental studies have shown, that the endothelium of cerebral vessels undergoes significant changes after subarachnoid haemorrhage which may lead to biochemical changes at the endothelial surface with disturbance of the delicate homeostasis of vasodilating and vasoconstricting mechanisms which are thought to be responsible for preservation of the tones of the cerebral vasculature. Ultrastructural studies incorporating different forms of microscopic observations of the endothelium after SAH representing a prerequisite for further investigations on the pathogenesis of cerebral vasospasm are scarce. The experimental study was performed in order to investigate and define more precisely the pathomorphological changes at the endothelial surface of the basilar artery of dogs after experimental SAH. Two separate injections of autologous blood into the cisterna magna within 72 hours resulted in extensive angiographic narrowing of the diameter of the basilar artery of all animals. Histological studies of the basilar artery including light microscopic, transmission electron microscopic, scanning electron microscopic and freeze cracking microscopic examinations demonstrated severe pathomorphological changes at the endothelial surface. These consisted mainly of infolding and corrugation of the endothelium, disorientation and desquamation of endothelial cells as well as of vacuolation and ingrowth of fibrous tissue between the endothelial and muscular layer. No pathomorphological changes could be observed in the muscular layer. As the described post-haemorrhagic ultrastructural changes of the endothelium cerebral vessels in spasm are likely to represent the morphological basis of the delayed form of cerebral vasospasm future research on its pathogenesis should primarily focus on the structural and biochemical taking place at the endothelial surface of the cerebral vasculature after SAH.

Management of cerebral aneurysms: further facts and additional myths

In 1985 we reviewed 17 misconceptions or myths surrounding the treatment of aneurysmal subarachnoid hemorrhage that may contribute to the dismal outcome from these lesions. Since that time, significant new data, or facts, have become available regarding the influence of early aneurysm surgery on rebleeding, the efficacy of treatments for symptomatic arterial narrowing, improvements in surgical techniques such as temporary arterial clipping, and measures to protect the brain from ischemic injury. However, additional myths have become apparent which continue to limit our ability to improve the outcome of these patients. We review these facts and myths and discuss management of the patient with aneurysmal subarachnoid hemorrhage.

Timing of surgery for cerebral aneurysms: a plea for early referral

Two groups of patients with aneurysmal subarachnoid haemorrhages--111 patients who underwent surgery within three days of haemorrhage, and 203 patients who underwent operations four or more days after the haemorrhage--were compared. No significant differences were found in outcome between the two groups. This indicates that early operation, which has the advantage of minimizing the risk of recurrent haemorrhage, is safe. The importance of the early diagnosis of subarachnoid haemorrhage and of an urgent referral for neurosurgical management is stressed.

Timing of operation for ruptured supratentorial aneurysms: a prospective randomized study

A total of 216 patients with a ruptured aneurysm of the anterior part of the circle of Willis were enrolled into this prospective randomized study of timing of the operation after aneurysmal subarachnoid hemorrhage (SAH). Only patients in clinical Grades I to III (according to the classification of Hunt and Hess) who were admitted and randomly assigned to a treatment group within 72 hours after the SAH were included in the trial. The patients were randomly assigned to one of three operation groups: acute surgery (AS: 0 to 3 days after the SAH; day of SAH = Day 0), intermediate surgery (IS: 4 to 7 days after the SAH), or late surgery (LS: 8 days to an indefinite time after the SAH). Three patients (4.3%) in the IS group and six patients (8.6%) in the LS group died before surgery was undertaken. At 3 months post-SAH, 65 patients (91.5%) from the AS group were classified as independent compared to 55 (78.6%) from the IS group and 56 (80.0%) from the LS group. The management mortality rate in the AS group was 5.6% compared to 12.9% in the LS group. Of the 216 patients enrolled in the timing study, 159 were randomly assigned to an independent double-blind placebo-controlled trial of nimodipine in Grade I to III patients. A total of 79 patients received nimodipine and 80 placebo. When the nimodipine group and the no-nimodipine group (the 80 placebo-treated patients plus the 52 patients who were not entered into the nimodipine trial) were analyzed separately, a significant difference was seen in the outcome of the no-nimodipine group (dependent AS vs. dependent IS, p = 0.01). Nimodipine treatment was associated with a significant reduction of delayed ischemic deterioration (all operation group combined, nimodipine vs. no nimodipine p = 0.01; LS with nimodipine vs. LS with no nimodipine, p = 0.03).

Symptomatic arterial luminal narrowing presenting months after subarachnoid hemorrhage and aneurysm clipping

The authors describe three cases of clinical cerebral ischemia associated with angiographic evidence of cerebral arterial luminal narrowing presenting 7, 14, and 52 weeks after subarachnoid hemorrhage (SAH) and aneurysm clipping. Delayed vasospasm, in its usual time setting 1 or 2 weeks after hemorrhage, did not occur symptomatically in these patients. No evidence for aneurysm clip migration or rebleed was present. All patients responded favorably to volume expansion and elevation of blood pressure. This unusual occurrence of a very delayed vasospasm may further the understanding of the vasospastic process. The symptomatic onset of arterial luminal narrowing months after SAH may suggest that a proliferative vasculopathy more accurately explains the observed vessel narrowing, rather than conventional active constriction of vascular smooth muscle.

Nimodipine treatment of selected good-risk patients with subarachnoid hemorrhage: no significant difference between present and historical results

Eighty-four patients were treated early with nimodipine intravenously, and thereafter orally, up to 21 days after aneurysmal subarachnoid hemorrhage. Thirty-nine patients in the nimodipine-treated group were carefully selected to be compared with similar patients from a historical control group (114 patients) conventionally treated. The causes of poor results were clinically identified as follows: delayed ischemic deterioration (DID), rebleeding, complications of surgery, or not defined. There was no significant difference in the distribution of DID or outcome at follow-up examination (at least 6 months later) between the nimodipine-treated group and the control group.

Timing of aneurysm surgery. Comparison of results of early and delayed surgical intervention

In a retrospective study covering a period of 8 years and 403 surgically treated patients the results of microsurgical aneurysm treatment were compared between two groups. One group received surgical treatment within 72 h and the second were treated surgically after this time interval. The data indicated that patients receiving delayed surgery had a better outcome at 6 months as compared to patients receiving immediate surgical intervention. The location of the aneurysm and the preoperative neurological status imparted the most significant impact on the subsequent outcome and on the incidence of rebleeding. High risk patients with poor neurological status on admission seemed to have a considerable chance of gaining satisfactory functional recovery, especially with a more delayed surgical approach. Despite its superior results delayed surgery was burdened with a rebleeding rate and an incidence of ischemic deficits due to cerebral vasospasm twice as high as in patients receiving early surgery. The implications of these results on surgical timing are discussed and it is concluded that despite the fact that late surgery yields better results than early surgery, the considerable reduction of recurrent hemorrhage and additional possibility of aggressive treatment of incipient vasospasm makes early surgery a promising alternative for the treatment of patients with aneurysmal subarachnoid hemorrhage.

Accumulation of intimal platelets in cerebral arteries following experimental subarachnoid hemorrhage in cats

From 2 hours to 23 days following experimental subarachnoid hemorrhage, the accumulation of indium-111-labeled platelets on the intimal surface of the middle cerebral artery was studied in 23 cats. Subarachnoid hemorrhage was produced by transorbital rupture of the right middle cerebral artery. Of the 23 cats, 17 exhibited right middle cerebral artery/left middle cerebral artery radioactivity ratios of greater than 1.25. When these results were compared with those of 12 control cats, 0.001 less than p less than 0.005 (chi2 test). Thus, the results from the control and experimental groups are significantly different and indicate early (after 2 hours) preferential accumulation of intimal platelets in the ruptured right middle cerebral artery compared with the unruptured left middle cerebral artery and new platelet deposition continuing for up to 23 days. However, the experimental group did not reveal a clear pattern for platelet accumulation following subarachnoid hemorrhage. There was no simple correlation between the magnitude of the radioactivity ratios and the time after hemorrhage when the cats were killed although the ratios for 2 hours to 7 days seemed greater than those for 8 to 23 days. Assuming the pivotal role of platelets in the angiopathy of subarachnoid hemorrhage, the administration of antiplatelet agents as soon as possible following its occurrence may be of value.

Significance of "ultra-early" rebleeding in subarachnoid hemorrhage

Knowledge of the local incidence of aneurysm rupture permits the conclusion that almost every patient in the population of 933,800 persons served by the authors' institution who was stricken by this catastrophe and survived long enough to be transported was treated at this center (121 patients during 34 months). Of these, 9.1% were admitted late (greater than 72 hours after subarachnoid hemorrhage (SAH]; of the remaining cases, 94.5% were seen within 24 hours and 50% within 6 hours post-SAH. Of the 121 patients, 10% were neurologically devastated on arrival, a late operation was planned for 19%, and the earliest possible surgery and nimodipine administration was selected for 71%. In this latter group, 50% of the operations were begun within 24 hours and 76% within 48 hours post-SAH. Sixty percent of all mortality and morbidity could be linked to the initial aneurysm bleed. The remaining 40% could be ascribed to potentially avoidable causes of unfavorable outcome. No less than 9.6% of all patients admitted within 24 hours after SAH suffered from "ultra-early" rebleeding during transportation or preparation for operation. The mortality rate from such rebleeding was 7.4%, compared with the 9.1% combined mortality rate from complications and late ischemia.

Results of treatment for cerebral saccular aneurysms in a small neurosurgical unit--evaluation of early operation and nimodipine treatment

91 patients in Hunt and Hess grade I to III directly after aneurysm rupture in the anterior circulation were treated by earliest possible surgery in conjunction with parenteral Nimodipine. 96% of the cases were seen in this centre within 24 hours from bleeding and surgery was commenced in 78% within 48 hours post haemorrhage. 8% suffered from "ultra early" rebleds six of which proved fatal. 12% of the cases had medical and surgical complications whereas only 3% had permanent late ischaemic sequelae. This low incidence of ischaemia may suggest a beneficial effect from Nimodipine treatment. The need for an aggressive surgical approach to aneurysms in order to minimize the omnious impact of rebleedings is stressed, although the importance of complications and technical misadventures must also be taken into consideration.

Pathological changes in cerebral arteries following experimental subarachnoid hemorrhage: role of blood platelets

The role of blood platelets in producing early intimal changes in cerebral arteries following subarachnoid hemorrhage (SAH) was examined by using 18 cats. Experimental SAH was produced by a rupture of the proximal portion of the right middle cerebral artery. Following SAH, the scanning electron microscope revealed that structural alterations in the intimal layer of major cerebral arteries occurred as early as 2 hours and became more severe by 48 hours. Vascular alterations, which were predominantly detected in the ruptured vessel, consisted of endothelial cell corrugation, detachment, crater formation, intimal adhesion of platelets and red blood cells, intimal thrombi, and reendothelialization. When cats were pretreated prior to SAH with an anti-platelet-aggregating agent, OKY-1581, the intimal blood elements and thrombi were clearly reduced, and reendothelialization was not observed. However, endothelial cell changes in the OKY-1581-treated group were very similar to those occurring in the nontreated group. While these results suggest that bioactive substances contained within blood platelets, such as growth factors, serotonin, and norepinephrine, have little effect on producing endothelial cell injury, platelets may be important in the initiation of reendothelialization following vessel injury.

Aneurysmal subarachnoid haemorrhage: overall outcome and incidence of early recurrent haemorrhage despite a policy of acute stage operation

A series of 480 patients who were alive upon admission following an aneurysmal subarachnoid haemorrhage (SAH) is reported. These patients represented 40% of the total Swedish incidence during a 3-year period. The three neurosurgical referral centres covering this population had a similar policy of early diagnosis and acute state surgery in all patients considered of having a potential to survive without permanent disabling cerebral malfunction. At 2-year follow up 45% showed a good neurological recovery, the morbidity was 25% and the mortality was 30%. Some more lives might have been saved with an improved ultra-early referral system since there were 21 initially good-to-fair risk patients (4% of the total SAH population) who rebled fatally before surgery and within 48 h. For comparison, in the Kingdom of Denmark, with a general policy of delayed operation, out of 1076 patients who were alive upon admission, 27.5% made a good recovery, while the morbidity was 27%, and the mortality was 45.5%.

Unruptured intracranial aneurysms: an assessment of the annual risk of rupture based on epidemiological and clinical data

From autopsy and neuroradiological studies a maximum prevalence of unruptured intracranial aneurysms (UA) of 0.5% in the general population is revealed. Studies concerning the incidence of aneurysmal subarachnoid haemorrhage (SAH) revealed 10 cases per 100,000 inhabitants per year. From these epidemiological parameters a minimum annual risk of 2% of rupture of an UA is calculated. It is in accordance with clinical studies, which also demonstrated an annual risk of UA rupture of at least 2%. No critical size of the UA predisposing to rupture has been found. Operation on diagnosed UA is recommended because of the serious prognosis after aneurysmal SAH (morbidity 20%-25% and mortality 50%-60%) and because the morbidity (4%) and the mortality (0%) after operative treatment of UA are very low.

Does the timing of aneurysm surgery neglect the real problems of subarachnoid haemorrhage?

In 1984, in connection with the introduction of the calcium antagonist nimodipine, a new strategy for the treatment of subarachnoid haemorrhage (SAH) due to ruptured aneurysm was developed in our hospital. With no rigid regard to "timing" all patients undergo surgery as soon as possible. The only exception being those in Hunt and Hess grades IV and V without space-occupying intracranial haemorrhage and those bearing aneurysms of the vertebrobasilar circulation that are difficult of access. As soon as the risk of rebleeding has been eliminated surgically an active therapy against the possible consequences of SAH--cerebral vasospasm and simultaneous disturbances of autoregulation--is started. It consists in lowering the increased intracranial pressure, raising of mean arterial pressure and improving of rheological properties of the blood in order to prevent delayed build-up of neurological deficit due to ischaemia. It goes without saying that calcium antagonists are given from the very beginning of the patient's treatment even before operation. The advantages of this therapeutic concept are demonstrated by two series of non-selected consecutive patient material. The first series (A; n = 135) was treated between 1981 and 1984 before the change in treatment strategy, the second (B; n = 183) from 1984 to 1986 after that change. The overall mortality in series A was 27%, that in series B 20%. Operative mortality could be reduced from 22% to 16% in patients having undergone early operation and from 6% to 2% in patients with late surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Benign subarachnoid haemorrhage (subarachnoid haemorrhage of unknown aetiology)

Forty three patients of subarachnoid haemorrhage of unknown aetiology have been studied for their clinical presentation, rebleed rate, morbidity and mortality. The results have been compared with other similar studies. The present study and those of others indicate a very good prognosis in acute stage. The rebleed rate ranged between 0 and 7% over a period of two to three years. The mortality rate ranged between 0 and 5% during the same period of follow-up. Majority of the patients returned to their full working capacity. The benign nature of this subgroup as compared to the poor outcome of subarachnoid haemorrhage as a whole prompted us to call it "Benign subarachnoid haemorrhage".

Geriatric neurosurgery

The "elderly," aged 65 and over, represent a rapidly growing proportion of the American population. Their percentage among the neurosurgical admissions at Henry Ford Hospital increased from 14.4% in 1978 to 22.4% in 1984. Occlusive cerebrovascular disease was the most frequent pathology seen, representing 40% of the population studied. Spinal degenerative myeloradiculopathy represented 14%, tumors 7%, trauma 5.4%, and intracranial hematomas represented 4% of the population. Vascular anomalies represented 3.3% of the patient group, with almost the same number of patients presenting with intracranial hemorrhage. The percentage of patients who were surgically treated was 58%. Mortality was 6.5%, with only 2.5% of the patients requiring special-care-facility placement following release from the hospital. An older group, aged 85 and over, represented 4% of our geriatric population. In the age 85+ group, occlusive cerebrovascular disease was the leading pathology (18% of the population), followed by subdural hematomas (15%), spinal degenerative myeloradiculopathy (11.6%), trigeminal neuralgias (7%), hydrocephalus (4%), vascular anomalies (4%), and tumors (4%). Patients in the age 85+ group were surgically treated in 41% of the cases, with a mortality of less than 10%. In the past, older age (greater than 65 years) was believed to be a contraindication to surgery, however, the increased life expectancy, number, and health of this population made reconsideration of this arbitrary age limit essential. We feel that age alone is not a barrier to proper neurosurgical treatment when other risk factors are adequately managed.

Evaluation of the role hemoglobin in cerebrospinal fluid plays in producing contractions of cerebral arteries

Many investigators have concluded that hemoglobin is the spasmogen responsible for cerebral vasospasm. The present study was designed to ascertain whether the contractile responses of isolated canine basilar arteries to xanthochromic cerebrospinal fluid from subarachnoid hemorrhage patients was associated with hemoglobin concentration as measured spectrophotometrically. The results clearly showed that spasmogenicity and hemoglobin content were not correlated. The magnitude and duration of the arterial responses varied greatly, further indicating that more than a single factor was responsible. The potent antagonistic, vasodilator effect of such proteins as antithrombin III may account for some of the variation, but the results directly complement clinical findings of others indicating that hemoglobin is not the singular cause of cerebral vasospasm.

Age as a prognostic factor after intracranial aneurysm rupture

1,076 patients with ruptured aneurysms admitted to neurosurgical units in Denmark over a period of 5 years were followed up for 2 years. The outcome as regards survival and normality of mental state was assessed in relation to age, clinical grade, and whether or not surgery was performed. For all ages and grades operated patients did better than those not operated on. Age seemed to have no bearing on outcome except for operated on good condition patients (grades 1-3) under the age of 40 years, who were significantly more likely to have a normal mental outcome than other groups.

Clinical features and outcome in 1076 patients with ruptured intracranial saccular aneurysms: a prospective consecutive study

In a well-defined area, The Kingdom of Denmark, 1076 patients with ruptured intracranial aneurysms were admitted to the six Danish neurosurgical departments in a prospective consecutive study in the 5-year period 1978-1983. Follow-up examinations were accomplished 3 months and 2 years after the admission. A total of 674 women and 402 men with a median age of 49 years were included in the study. The localisation of the ruptured aneurysms were: internal carotid artery 285, anterior communicating artery and horizontal part of anterior cerebral artery 383, middle cerebral artery 291, basilar and vertebral arteries 83 and peripheral or other localisation 34. A significantly better outcome was seen in cases with internal carotid aneurysms compared to other localisations. 670 patients underwent operation. A highly significantly better outcome was found in operated versus non-operated patients in comparable clinical conditions. The advantage of microneurosurgery was well documented. Patients with vasospasm had a significantly worse outcome. Within the first 2 weeks a daily rebleeding rate from 0.2% to 2.1% was observed, and patients who rebled had a significantly worse outcome compared to patients, who did not rebleed. The overall outcome at 2-year follow-up was: normal 27.5%, mild dementia 15.8%, severe dementia 9.9%, vegetative 1.3% and mortality 45.5%.

Subarachnoid hemorrhage: a review

Subarachnoid hemorrhage from the rupture of a saccular aneurysm remains a major neurosurgical problem that affects 25,000 to 28,000 people yearly. Unfortunately, the mortality from this devastating disease process has not changed significantly in the last 30 years. For emergency physicians, the early detection and diagnosis of subarachnoid hemorrhage is critical to the potential of reducing the mortality from such an event. This article reviews and updates the natural history of subarachnoid hemorrhage, its incidence, presentation, diagnosis, and management from the standpoint of the emergency physician. It does not explore all controversial areas in exhaustive depth, but rather summarizes material that is of importance to emergency physicians in their approach to the problem.

Management of ruptured intracranial aneurysm: a review

The discouraging history associated with management of aneurysmal subarachnoid haemorrhage (SAH) is reviewed along with improvements in outlook attributable to progress made within the past decade. Among the new developments is the introduction of microsurgical techniques that allow elective surgery in the acute stage thereby preventing repeat haemorrhages. Early operation also offers the possibility of a more aggressive pharmacological anti-ischaemic treatment. Notwithstanding the improved results of acute elective surgery and the fact that delayed ischaemic deterioration (symptomatic cerebral vasospasm) now may be almost eliminated, the overall outcome remains gloomy. Despite recent advances not more than one out of three individuals, who are struck by the rupture of an intracranial aneurysm, may be expected to make a good neurological and functional recovery. Hope for further improvements may depend on the development of techniques that can identify intracranial aneurysms before they rupture and increased knowledge of the aetiology of such arterial wall lesions.