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The neuroprotective effect of mexiletine (Mex), a potent Na(+) channel blocker which decreases neuronal energy demands and prevents energy depletion during ischemia, was evaluated in Wistar rats subjected to permanent middle cerebral artery (MCA) occlusion. Postmortem infarct volumes were determined by quantitative image analysis of triphenyltetrazolium (TTC)-stained brain sections. Pretreatment with Mex resulted in a significant infarct volume reduction when administered intraperitoneally, either at the dosage of 50 or 60 mg/kg, 1 hr before MCA occlusion (P < 0.05). Delayed treatment with Mex (50 mg/kg) also had neuroprotective effects when given at 0.5 hr (< 0.05), but not 2-4 hr, after MCA occlusion. Intraarterial administration of MgSO(4) (90 mg/kg), in combination with Mex at 60 mg/kg, showed no additive neuroprotective effect, although each agent independently reduced the MCA occlusion-induced infarction volume (P < 0.05). Our results indicate that a single, acute administration of Mex is neuroprotective against permanent focal cerebral ischemia, but perhaps chronic administration is needed to establish a more effective therapeutic window beyond 0.5 hr. Moreover, the present in vivo data do not favor a combined use of Mg(2+) with Mex for limiting ischemic injury in the brain, since these agents caused cardiopulmonary suppression, which may have led to the loss of the neuroprotective effect of each agent independently., (Copyright 1999 Wiley-Liss, Inc.)

Surgical experience with angiographically occult vascular malformations, specifically cavernous malformations (CMs), has increased substantially over recent years. CMs are generally well-circumscribed, low-pressure vascular lesions amenable to resection. Overall, results obtained with operative management have been favorable; however, the location of the lesion impacts significantly on the outcome and morbidity of surgery, with those located within deep and brain stem regions carrying a higher incidence of persistent neurologic complications. As knowledge emerges regarding the long-term natural history of these lesions, the role of operative intervention in cases where surgical morbidity is high will become better defined.

The indications for the surgical management of supratentorial cavernous malformations are outlined and the results following operation are presented in this article. Surgery is indicated for most patients who present with seizures, neurologic deficit, or headache. The surgical approaches to lesions in the cerebrum are described. The operative morbidity and mortality are low. Over 95% of all patients have excellent or good results and return to their previous level of activity.

Background: Blood flow turbulence and increased shear stress, particularly at sites of sudden, marked arterial wall changes, are significant hemodynamic parameters in the pathogenesis of atherosclerosis. We present a case in which we found the hyoid bone protruding into the carotid vessels and may have been contributing, in part, to atherosclerotic carotid stenosis., Case Presentation: An 85-year-old woman presenting with left arm and leg weakness consistent with right hemispheric transient ischemic attack. Magnetic resonance arteriography (MRA) and carotid non-invasive studies revealed a 90% stenosis of the right internal carotid artery. At surgery, the hyoid bone on the right side was projecting into the internal carotid artery, causing indentation. There was associated rotation of the internal and external carotid arteries from their normal position. Right carotid endarterectomy was performed and the lateral one-third of the hyoid bone excised to alleviate the external compression. Postoperative spiral computerized tomography (CT) scan of the carotid vessels demonstrated the extent of hyoid resection as well as rotation of the external and internal carotid arteries., Conclusions: We suggest the possible contribution of hyoid bone compression to the pathogenesis of atherosclerotic carotid artery stenosis. This report also highlights the diagnostic value of CT angiography in the assessment of carotid artery occlusive disease.

We describe a head tilt technique for use with CT angiography that reduces beam-hardening artifacts in patients with aneurysm clips. This simple maneuver directs the artifacts away from pertinent anatomy, thus increasing the chances for diagnostic accuracy. No significant changes in the CT angiographic protocol are required, and the maneuver can easily be combined with other artifact-minimizing strategies.

Background and Purpose: Better measures of cerebral tissue perfusion and earlier detection of ischemic injury are needed to guide therapy in subarachnoid hemorrhage (SAH) patients with vasospasm. We sought to identify tissue ischemia and early ischemic injury with combined diffusion-weighted (DW) and hemodynamically weighted (HW) MRI in patients with vasospasm after SAH., Methods: Combined DW and HW imaging was used to study 6 patients with clinical and angiographic vasospasm, 1 patient without clinical signs of vasospasm but with severe angiographic vasospasm, and 1 patient without angiographic spasm. Analysis of the passage of an intravenous contrast bolus through brain was used to construct multislice maps of relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF), and tissue mean transit time (tMTT). We hypothesize that large HW imaging (HWI) abnormalities would be present in treated patients at the time they develop neurological deficit due to vasospasm without matching DW imaging (DWI) abnormalities., Results: Small, sometimes multiple, ischemic lesions on DWI were seen encircled by a large area of decreased rCBF and increased tMTT in all patients with symptomatic vasospasm. Decreases in rCBV were not prominent. MRI hemodynamic abnormalities occurred in regions supplied by vessels with angiographic vasospasm or in their watershed territories. All patients with neurological deficit showed an area of abnormal tMTT much larger than the area of DWI abnormality. MRI images were normal in the asymptomatic patient with angiographic vasospasm and the patient with normal angiogram and no clinical signs of vasospasm., Conclusions: We conclude that DW/HW MRI in symptomatic vasospasm can detect widespread changes in tissue hemodynamics that encircle early foci of ischemic injury. With additional study, the technique could become a useful tool in the clinical management of patients with SAH.

Ischemia depletes ATP and initiates cascades leading to irreversible tissue injury. Nicotinamide is a precursor of nicotinamide adenine dinucleotide (NAD+) which increases neuronal ATP concentration and protects against malonate-induced neurotoxicity, trauma and nitric oxide toxicity. We therefore examined whether nicotinamide could protect against stroke, using a model of permanent middle cerebral artery occlusion (MCA) occlusion in Wistar rats. Nicotinamide reduced neuronal infarction in a dose-specific manner. Furthermore, nicotinamide (500 mg/kg) reduced infarcts when administered up to 2 h after the onset of permanent MCA occlusion. The mechanism of action underlying the neuroprotection observed with nicotinamide remains to be clarified. These results are potentially important since nicotinamide is already used clinically, though not in the treatment of stroke.

Cavernous malformations of the spinal cord are extremely rare lesions. The 58 reported cases in the English literature and 9 of the authors' own cases are reviewed. The clinical presentation, patient characteristics, radiographic appearance, and histopathologic features are reviewed. The optimal surgical management and outcomes of treatment for intramedullary spinal cord cavernous malformations are discussed in detail.

Objective: Approximately 25% of patients with subarachnoid hemorrhage (SAH) have electrocardiographic (ECG) abnormalities consistent with myocardial ischemia or myocardial infarction (MI), and their cardiac prognosis remains unclear. The objective of this study was to determine the cardiac and all-cause mortality rate of a series of patients with SAH with ECG changes consistent with ischemia or MI., Methods: Using an existing database of patients with SAH and predetermined ECG criteria for ischemia or MI, a study group of patients with abnormal ECG results within 3 days of presentation and before aneurysm surgery was identified. Database patients without abnormal ECG results served as a control group. Cardiac mortality, defined as death resulting from arrhythmia, congestive heart failure, or cardiogenic shock, was assessed by chart review., Results: Of 439 patients with SAH in the database, 58 met the criteria for the study group. Forty-one of these patients were treated neurosurgically. No deaths resulting from cardiac causes occurred, and 20 patients died as a result of noncardiac causes. In a multivariable analysis, age older than 65 years and Hunt and Hess grade of at least 3 were predictive of all-cause mortality. ECG abnormalities, however, were not a statistically significant predictor., Conclusion: In patients with SAH and ECG readings consistent with ischemia or MI, the risk of death resulting from cardiac causes is low, with or without aneurysm surgery. The ECG abnormalities are associated with more severe neurological injury but are not independently predictive of all-cause mortality.

We determined whether exogenous Mg2+ and/or mexiletine (Mex), which are reported to be neuroprotective agents, reduced neuronal energy requirements and protected against ischemia, using isolated rabbit retinas. Under non-ischemic conditions, Mex (300 microM) and the combination of Mg2+ (1 mM) plus Mex (300 microM) significantly reduced glucose utilization, by 19% and 31%, respectively. The combination of Mg2+ plus Mex, but not either agent alone, significantly reduced lactate production (by 18%; p < 0.05). When added during 2 h of ischemia (simulated by the reduction of oxygen from 95% to 15% and of glucose from 6 mM to 1 mM), Mg2+ plus Mex improved the recovery of glucose utilization (p < 0.01), lactate production (p < 0.05) and neuronal function (p < 0.05) for 3 h following return to control (post-ischemia/recovery) conditions. Thus reducing energy demands by blocking functions during temporary ischemia, protects neurons from irreversible functional damage.

Cerebral cavernous malformation (CCM) is a Mendelian model of stroke, characterized by focal abnormalities in small intracranial blood vessels leading to hemorrhage and consequent strokes and/or seizures. A significant fraction of cases is inherited as an autosomal dominant trait with incomplete penetrance. Among Hispanic Americans, virtually all CCM is attributable to a founder mutation localized to 7q ( CCM1 ). Recent analysis of non-Hispanic Caucasian kindreds, however, has excluded linkage to 7q in some, indicating at least one additional CCM locus. We now report analysis of linkage in 20 non-Hispanic Caucasian kindreds with familial CCM. In addition to linkage to CCM1, analysis of linkage demonstrates linkage to two new loci, CCM2 at 7p13-15 and CCM3 at 3q25.2-27. Multilocus analysis yields a maximum lod score of 14.11, with 40% of kindreds linked to CCM1, 20% linked to CCM2 and 40% linked to CCM3, with highly significant evidence for linkage to three loci (linkage to three loci supported with an odds ratio of 2.6 x 10(5):1 over linkage to two loci and 1.6 x 10(9):1 over linkage to one locus). Multipoint analysis among families with high posterior probabilities of linkage to each locus refines the locations of CCM2 and CCM3 to approximately 22 cM intervals. Linkage to these three loci can account for inheritance of CCM in all kindreds studied. Significant locus-specific differences in penetrance are identified. These findings have implications for genetic testing of this disorder and represent an important step toward identification of the molecular basis of this disease.

Aneurysms of the vertebral and posterior inferior cerebellar artery (PICA) are uncommon. Surgical approaches to vertebral artery and PICA aneurysms and patient outcome using surgical or endovascular techniques are discussed in this article.

The temporary occlusion of cerebral vessels is being used with increased frequency in the surgical management of cerebral vascular disease, and this procedure places brain tissue at risk of infarction. Using a modified version of a well-established model of focal cerebral ischemia in the rabbit, we tested the protective effect of a combination of six agents; each agent was selected to temporarily block one or more neuronal functions, hence reducing their metabolic demands. The combination of six agents had been previously shown to protect neurological function against ischemia. Ten male adult New Zealand White rabbits were anesthetized with halothane, and physiological parameters were maintained within normal ranges. A branch of the left external carotid artery was catheterized and the vasculature supplying the left middle cerebral artery (MCA) territory was isolated. Mannitol was infused via the external carotid artery into the left internal carotid artery to open the blood-brain barrier in the territory of the MCA. This infusion was followed by either Ames' medium alone (control) or Ames' medium containing the combination of agents: tetrodotoxin (0.1 micromol/L), 2-amino-4-phosphonobutyric acid (20 mumol/L), 2-amino-5-phosphonovaleric acid (1 mmol/L), amiloride (1 mmol/L), magnesium (10 mmol/L), and lithium (10 mmol/L). Ischemia in the left MCA territory was then induced for 2 hours, followed by 4 hours of reperfusion. Animals pretreated with the combination of agents sustained infarctions that were markedly smaller (mean+/-SEM, 46+/-19.7 mm(3), n=5) than control animals (300+/-46.5 mm(3), n=5, P<.001). We conclude that the strategy of locally delivering a combination of agents designed to temporarily reduce neuronal metabolic demands by temporarily blocking several nonvital neuronal functions, can reduce the infarction induced by a focal reduction in cerebral blood flow in the rabbit.

Aspirin is widely used as an analgesic, in the secondary prevention of stroke, and has recently been suggested to be a putative neuroprotective agent, yet whether it acts directly on the central nervous system (CNS) is not yet clarified. We therefore examined the effect of lysine acetylsalicylate (L-ASA, 4-2000 microM) on neuronal function under normal conditions and following 1 h of ischemia using the in vitro rabbit retina preparation. L-ASA inhibited the light-evoked compound action potentials, but not the electroretinogram, in a concentration-dependent manner. In addition, L-ASA (2000 microM, but not 4, 40 or 200 microM) administered during ischemia, reduced the recovery of neuronal function compared to control (untreated) retinas. L-ASA therefore inhibits CNS neurotransmission, but not phototransduction, in a concentration-dependent manner. In addition, high concentration L-ASA impairs the recovery of neuronal function following an ischemic episode.

Objective: As more information evolves regarding the natural history of cavernous malformations (CMs), the risks of operative intervention must be balanced against nonoperative management. In an attempt to better delineate the surgical risks for operable CMs, we undertook a retrospective analysis of 94 patients with 97 CMs surgically excised at the Massachusetts General Hospital., Methods: Data regarding surgical complications and outcome measures, including neurological status and seizure outcome, were analyzed., Results: The incidence of transient neurological morbidity was 20.6%, but only 4 of the 97 operations (4.1%) resulted in persistent disabling neurological complications and 2 (2.1 %) in nondisabling deficits. There was no operative mortality. Brain stem lesions (n=14) were associated with the highest incidence of neurological complications, both transient and persistent (odds ratio, 4.8; 95% confidence interval, 1.5-15.7). The overall neurological outcome was excellent or good in 89.7% of all lesions: 96.8% of lobar CMs (n=63), 64.2% of brain stem CMs (n=14), 87.5% of cerebellar CMs (n=8), 100% of cranial nerve CMs (n=4), and 75% of spinal cord CMs (n=8). Patients with brain stem and spinal cord CMs were in poorer preoperative neurological condition than were patients with CMs in other locations and therefore had a significantly reduced level of function after surgery (P < 0.01). There was improvement in 35.7% of the patients with brain stem lesions and 62.5% of the patients with spinal cord lesions after surgery. In the 38 patients presenting with seizures, 97% were seizure-free after surgery., Conclusion: The risks of operative management of CMs varies based on location. When evaluating patients with operable CMs for surgery, the incidence of complications as well as final neurological outcome should be carefully weighed against the existing knowledge of the natural history of lesions managed expectantly.

Objective: The lack of treatment options for surgically inaccessible cavernous malformations has made radiosurgery a possible alternative to conservative management. The few previous reports of radiosurgical efficacy have been limited by small numbers, short follow-up, or lack of attention to the full spectrum of end points, including neurological disability. In an attempt to elucidate the risk-to-benefit ratio of radiosurgery for cavernous malformations, we undertook a retrospective analysis of of 95 patients with 98 lesions treated by the late Raymond N. Kjellberg., Methods: Patients were followed for an average of 5.4 years (range, 0.3-12.3 yr), and data regarding hemorrhage, seizure, neurological disability, and incidence of radiation-induced complications were gathered., Results: The analysis revealed a drop in annual hemorrhage rates from 17.3% per lesion per year before treatment to 4.5% per lesion per year after a latency period of 2 years. Improvement in seizure control was evident. However, a 16% incidence of permanent neurological deficit and a 3% mortality rate were attributable to radiographically confirmed radiation-induced complications. Neurological disability scores, measured by the modified Rankin disability scale, indicated a significant decline in neurological functioning during the follow-up interval, a result of the combined effects of radiation-related injury, hemorrhage, and clinical progression of the lesion., Conclusion: We conclude that although radiosurgery does seem to reduce hemorrhage, there is potential for complications and continued lesion progression after radiosurgery. These risks and benefits must be carefully balanced against the natural history of untreated lesions if the use of radiosurgery is considered.

Objective: By conducting a review of clinical outcomes for patients with aneurysms treated using current microneurosurgical techniques and intensive care unit management, we determined that grading systems based only on the clinical condition of the patient failed to produce a significant stratification of outcome between individual grades of patients. We hypothesized that outcome prediction for patients surgically treated for intracranial aneurysms could be improved by including factors other than clinical condition that were also strongly associated with outcome., Methods: To identify potential factors for inclusion in a risk prediction tool, we conducted a multivariate logistic regression analysis of patient- and lesion-specific factors suspected to be associated with outcome in a series of 434 aneurysm operations. Factors that were strongly associated with outcome were used to develop a comprehensive grading system. In the system, 1 point is assigned for Hunt and Hess Grade IV or V, Fisher Scale score of 3 or 4, aneurysm size greater than 10 mm, patient age older than 50 years, and if the lesion is a giant (> or =25 mm) posterior circulation lesion. By adding the total points, a 5-point grading system (Grades 0-5) is obtained., Results: Age of patient, size of aneurysm, severity of subarachnoid hemorrhage (Fisher Scale evaluation of density of blood present as revealed by computed tomography), and clinical condition (Hunt and Hess grade) were each independently and strongly (relative risk, >4) associated with long-term outcome. In addition, there was a trend for increased risk with larger (>25 mm) posterior circulation lesions. When applied to the study population, individual grades on the new grading scale correlated well with actual outcome. In a prospective assessment of the system as applied to an additional 72 operations with at least 1 year of follow-up, the correlation of individual grades and outcome was strong and validated the retrospective findings., Conclusion: This new grading system is easy to apply, separates patients into groups with markedly different outcomes, and is comprehensive, allowing for more accurate prediction of surgical outcome for both unruptured and ruptured cerebral aneurysms.

Objective: To characterize changes in regional blood flow (rCBF) during and after a period of arterial occlusion and determine the effect on rCBF and on the extent of infarction when the mean arterial blood pressure is increased during the period of occlusion., Methods: rCBF in the middle cerebral artery (MCA) territory of rabbits was monitored using laser Doppler perfusion imaging before, during, and after a 1- or 2-hour period of MCA occlusion, and the size of the infarction was assessed by 2,3,5-triphenyltetrazolamine chloride staining after 2 hours of reperfusion. Test animals, the mean arterial blood pressure of which was increased by 65 mm Hg with intravenous phenylephrine during the ischemia, were compared with control animals that remained normotensive. The laser Doppler perfusion imager (Lisca Developments Co., Linköping, Sweden) scanned a 3-cm2 area of cortex with a resolution of 4 mm2 every 15 minutes., Results: MCA occlusion reduced rCBF to 71 +/- 2% of the control level (n = 24, P < 0.001). Hypertension (HTN) restored rCBF to 84 +/- 3% of the control level (n = 12, P < 0.01), but the HTN-induced improvement diminished with time, so that after 1 hour, there was no longer a significant difference between hypertensive and normotensive animals. HTN during the MCA occlusion caused a 97% reduction in infarct size (P < 0.05) in the animals subjected to 1 hour of occlusion but caused only a 45% reduction (P approximately 0.1) in the animals subjected to 2 hours of occlusion., Conclusion: This study supports the use of HTN to minimize ischemic injury from short intervals of major intracranial vessel occlusion but fails to demonstrate protection when HTN is maintained during occlusions of more than 1 hour.

Background and Purpose: Transcranial doppler ultrasound (TCD) is used after subarachnoid hemorrhage to detect cerebral vasospasm and is often treated with induced hypertension. Cerebral autoregulation, however, may be disturbed in this population, raising the possibility that TCD velocities may be elevated by induced hypertension. To study this possibility, we performed continuous TCD monitoring of the middle cerebral artery during the induction and withdrawal of induced hypertension in patients after subarachnoid hemorrhage., Methods: Twenty-eight patients were studied during the induction and withdrawal of hypertension using primarily phenylephrine. Continuous monitoring was performed on the middle cerebral artery with the highest flow velocity. Treatment was based on rising TCD velocities or clinical evidence for cerebral vasospasm. Mean arterial pressure and mean TCD velocities were recorded every minute. A change of > 15% from starting TCD values was considered significant. Cerebral autoregulation was calculated as a percentage of intact autoregulation. Patients were subsequently divided into groups of disturbed and intact autoregulation., Results: In 10 of 19 patients (53%), TCD velocities changed by > 15% and paralleled changes in mean arterial pressure. This directly altered the TCD interpretation of the grade of vasospasm in 7 of 19 patients (36%). Three additional patients had smaller absolute changes in TCD velocities. No clinical difference could be identified between patients with disturbed and intact autoregulation., Conclusions: In patients with disturbed autoregulation after subarachnoid hemorrhage, induced hypertension can alter cerebral blood flow velocities. The level of autoregulation needs to be considered when interpreting TCD velocities in patients after subarachnoid hemorrhage.

Purpose: Our purpose was to determine the clinical feasibility of quantitative three-dimensional functional CT in patients with hyperacute stroke., Methods: Twenty-two patients who underwent clinically indicated CT angiography were studied: nine patients had no stroke, eight had mature stroke, and five had hyperacute stroke (less than 3 hours since ictus). Maps were obtained of perfused cerebral blood volume (PBV), and CT angiograms were generated by using standard techniques., Results: Normal PBV values (mean +/- SEM) were 4.6 +/- 0.15% in the gray matter, 1.75 +/- 0.09% in the white matter, 2.91 +/- 0.20% in the cerebellum, 3.18 +/- 0.10% in the caudate, 2.84 +/- 0.23% in the putamen, 2.92 +/- 0.29% in the thalamus, and 1.66 +/- 0.03% in the brain stem. For patients with mature stroke, ischemic changes were visible on noncontrast, contrast-enhanced, and PBV scans. In patients with hyperacute stroke, ischemic changes were either absent or subtle before contrast administration, but became apparent on contrast-enhanced scans. Quantitative PBV maps confirmed reduced regional perfusion. CT angiograms in the hyperacute group showed occlusion of vessels in locations appropriate to the PBV deficits seen., Conclusion: Quantitative three-dimensional functional CT is feasible for patients with hyperacute stroke. It is performed by using helical CT techniques, and yields measures of cerebrovascular physiological function, which are useful in this patient population.

Background and Purpose: Transcranial Doppler (TCD) is often used in conjunction with carotid duplex ultrasonography (CDUS) to evaluate the hemodynamic significance of internal carotid artery (ICA) stenosis. We examined the sensitivity and specificity of TCD criteria for detection of a hemodynamically significant stenosis (residual lumen diameter < 1.5 mm) at the origin of the ICA., Methods: We selected patients who underwent carotid end-arterectomy (CEA) and had preoperative TCD data available. Eighty-one patients underwent transorbital evaluation, 49 of whom also had transtemporal TCD performed. The endarterectomy specimens were removed en bloc and sectioned, and the minimal residual lumen diameter calculated by computer analysis., Results: For the transorbital approach, the strongest indicators of a residual lumen diameter < 1.5 mm were reversed flow in the ipsilateral ophthalmic artery and a > 50% peak systolic velocity difference between the carotid siphons (distal ICAs) in patients with unilateral ICA origin stenosis. They were 100% specific and 31% and 26% sensitive, respectively. For the transtemporal approach in patients with a unilateral stenosis, a > 35% difference in ipsilateral middle cerebral artery (MCA) peak systolic velocity relative to the contralateral MCA or a > 50% difference in contralateral anterior cerebral artery (ACA) peak systolic velocity relative to the ipsilateral ACA were 100% specific for identifying a residual lumen diameter of < 1.5 mm. Sensitivities were 32% and 43%, respectively. Irrespective of contralateral stenosis, a > 35% difference in ipsilateral MCA peak systolic velocity relative to the ipsilateral posterior cerebral artery had a 100% specificity and a 23% sensitivity for detecting a < 1.5 mm minimal residual lumen diameter., Conclusions: Although the TCD sensitivity for detecting a hemodynamically significant stenosis is relatively low, it can be highly specific (up to 100%). We conclude that TCD enhances the specificity of highly sensitive CDUS criteria for detecting a hemodynamically significant ICA stenosis.

Isovolemic hemodilution with polymerized bovine hemoglobin (PoBH) was tested as a means of preventing infarction in a rabbit model of focal cerebral ischemia. The animals were divided into one control group and one hemodilution group. All animals underwent two hours of ischemia, caused by clipping the left internal carotid artery, the anterior cerebral artery, and the middle cerebral artery, followed by 4 hours of reperfusion. In the control group, the hematocrit was not manipulated (mean +/- SE: 33.8 +/- 1.3%), while in the hemodilution group, the Hct was reduced to 12.5 +/- 1.9% by exchange of blood with PoBH, before clipping the cerebral vessels. Staining with 2,3,5- triphenyltetrazolium chloride (TTC) was used to evaluate the infarct size. The infarct volume was 427 +/- 52 mm3 in the control animal, and 1026 +/- 311 mm3 (p < 0.01 when compared with the control group) in the animal hemodiluted with PoBH. PoBH hemodilution was found to be associated with vasoconstriction. This pathological vasoconstriction probably counteracted any beneficial effects from the lowered viscosity and explains our negative results. Vasoconstriction has to be overcome before hemodilution can have its beneficial effect in reducing the cerebral ischemia.

Objective: To review a technique used to repair a hole in the carotid artery encountered during the dissection and clipping of a giant paraclinoid aneurysm., Methods: The technique of repair involves wrapping the artery using a woven double velour material impregnated with bovine collagen (Hemashield; Meadox, Oakland, NJ) and securing the material around the carotid artery with an aneurysm clip. The intravascular pressure of the carotid artery provides the counterforce necessary to seal the hole., Results: The carotid artery was slightly narrowed after the treatment. The patient made an excellent recovery from surgery., Conclusion: This technique provides an alternative means of repairing a defect in the walls of intracranial arteries.

Objective: Massive cerebral infarction is often accompanied by early death secondary to transtentorial herniation. We have tested the hypothesis that decompressive hemicraniectomy for massive nondominant cerebral infarction is lifesaving in a series of 14 patients presenting with right hemispheric infarction and clinical signs of uncal herniation and impending death. We have further analyzed, in prospective follow-up examinations, the levels of physical, psychiatric, and social disabilities in these patients., Methods: The methods used included retrospective analysis to determine rates of immediate mortality and morbidity after surgical intervention. Prospective follow-up data were obtained to determine the level of recovery in surviving patients after 1 year. Standardized measures of outcome to assess physical, psychiatric, and social recovery included the Barthel Index, Zung Depression Scale, and Reintegration to Normal Living Index., Results: With decompressive hemicraniectomy, we were able to prevent death secondary to transtentorial herniation in all cases; 11 patients experienced long-term survival after the procedure, and three deaths were related to non-neurological causes. We observed that 8 of the 11 surviving patients were at home, were functioning with minimal to moderate assistance, and had Barthel scores greater than 60. The remaining three patients were severely disabled. Seven of the 11 survivors were able to walk at 1 year after undergoing the procedure. Depression and failure to reintegrate socially were experienced by most patients., Conclusion: This series confirms the lifesaving nature of hemicraniectomy in patients deteriorating because of cerebral edema after infarction. In patients younger than 50 years, recovery to a state of near-independence is possible.

Objective: To evaluate the safety and any potential effect of cyclosporine A (CycA) in preventing cerebral vasospasm., Methods: Nine patients with Fisher Grade 3 subarachnoid hemorrhages were studied. After a loading dose of 7.5 mg/kg of CycA was administered every 12 hours for two doses, enteral treatment with CycA was started within 72 hours of the onset of the subarachnoid hemorrhage. Whole blood CycA levels were titrated to maintain levels of 50 to 400 ng/kg. Transcranial doppler ultrasonography was performed daily. Middle cerebral artery velocities were used to assess the degree of vasospasm. Angiography was performed to confirm the vasospasm in symptomatic patients, or it was performed if transcranial doppler ultrasonograms were unobtainable. Patients were treated with a standard pharmacological regimen of nimodipine. Induced hypertension, hemodilution, and hypervolemia were instituted at the discretion of the neurosurgical team. Intra-arterial papaverine was infused into the vasospastic vessels of three recalcitrant patients. Outcome was assessed at 6 months with the Glasgow Outcome Scale., Results: All the patients displayed evidence of vessel narrowing, which was disclosed by transcranial doppler ultrasonography or angiography. Five patients developed ischemic deficits, two were treated with intra-arterial papaverine, and three died of complications secondary to vasospasm. No significant hepatic, renal, or infectious complication developed as a result of the administration of CycA., Conclusions: CycA proved safe to use but failed to prevent the development of cerebral vasospasm or delayed ischemic deficits in patients considered at high risk.

Dissecting aneurysm of the basilar artery is a rare but increasingly recognized entity, with a frequently fatal or morbid outcome. Unlike the well established proximal occlusion and trapping approaches to vertebral artery dissections, surgical intervention for basilar lesions has been limited to wrapping techniques for arterial wall reinforcement. We report a case of midbasilar dissecting aneurysm successfully treated by clipping the proximal basilar artery below the level of the anterior inferior cerebellar arteries, allowing retrograde flow via the posterior communicating arteries to provide continued basilar perfusion. With the growing recognition of basilar dissection and pseudoaneurysm formation there is a need for improved therapeutic options. We suggest that definitive treatment can be achieved using the principle of proximal occlusion and flow reversal, and review the pertinent literature on basilar artery dissection.

We report management and outcome data on 118 patients that presented to our emergency room over a 4 year interval (1990-1994) in poor neurological condition after subarachnoid hemorrhage. All patients were treated following a strict protocol. After initial evaluation, patients underwent a head computerized tomography (CT) scan to try to understand the mechanism of coma. If CT did not show destruction of vital brain areas, a ventriculostomy was inserted and ICP measured. If ICP was less than 20 mm Hg, or if standard treatment of increased ICP was able to lower the ICP to a value less than 20 mmHg, patients were evaluated with cerebral angiogram to determine the location of the ruptured aneurysm. The lesion was then treated by craniotomy for aneurysm clipping or endovascular obliteration. Postoperative monitoring for vasospasm with clinical exam and transcranial doppler studies was performed routinely. If vasospasm developed, this was managed aggressively with hypertensive, hypervolemic and hemodilutional therapy and, at times, endovascular treatment with angioplasty or papaverine. Outcome was measured at 1 year or more after treatment. Among patients who met criteria for aneurysm treatment, 47% had excellent or good neurologic outcome. There was a 30% mortality rate in these patients. In patients with high ICP, poor brainstem function or destruction of vital brain areas on CT, comfort measures only were offered and almost all died. It is concluded that an approach of early aneurysm obliteration and aggressive medical and endovascular management of vasospasm is warranted in patients in poor neurological conditions after subarachnoid hemorrhage.

The pathophysiology of subarachnoid hemorrhage (SAH) may involve free radical production and lipid peroxidation. We examined plasma levels of cholesteryl ester hydroperoxides (CEOOH) and antioxidants in 25 patients with SAH, and 10 neurologic controls with lacunar stroke. Patients with SAH had significantly increased plasma levels of CEOOH, which peaked on day 5 after the ictus. Concentrations of CEOOH were significantly increased, and ascorbic acid concentrations were significantly decreased in patients who developed vasospasm compared with patients without vasospasm. Increased levels of CEOOH were associated with increased mortality and correlated with clinical outcome scales. These results implicate oxidative stress in the pathogenesis of SAH and suggest that measurements of CEOOH in plasma may be useful both prognostically as well as in monitoring therapeutic interventions.

We examined the effect of modulating endogenous nitric oxide (NO) production on the recovery of neuronal function from temporary ischemia using a preparation in which blood flow is not a factor. Inhibition of nitric oxide synthase (NOS) during ischemia with L-NA (100 mumol-1) resulted in worse functional recovery compared to D-NA (100 mumol-1)-treated in control retinas (p < 0.01). In contrast, addition of L-Arg (1000 mumol-1) during ischemia, resulted in a concentration-dependent functional improvement (p < 0.05). These results show that inhibition of constitutive NOS is detrimental, whilst the enhancement of endogenous NO production improves the recovery of neuronal function during a period of temporary ischemia in the isolated retina, (an in vitro avascular model of the CNS). Thus, independent of its effects on the vasculature, NO production during temporary ischemia protects neurons from irreversible function damage.

Background and Purpose: Carotid duplex ultrasound is widely used to screen patients for carotid endarterectomy and if combined with MR angiography and transcranial Doppler may be an alternative to conventional angiography in the preoperative assessment. We have examined the correlation between Doppler velocities and the residual lumen diameters of internal carotid arteries from surgical pathological specimens to establish Doppler criteria for residual lumen diameter independent of percent stenosis., Methods: Ninety-one patients who underwent 99 carotid endarterectomies for internal carotid artery stenosis within 6 months of their carotid duplex ultrasound evaluation were studied. The endarterectomy specimens were removed en bloc, and the minimal residual lumen diameter was calculated by computer analysis. The sensitivity and specificity of the Doppler criteria for determining high-grade stenosis were calculated and receiver-operator curves generated., Results: Peak systolic velocity (PSV), end-diastolic velocity (EDV),and carotid index (peak internal carotid artery velocity/ common carotid artery velocity) correlated with the residual lumen diameter. PSV > 440 cm/s, EDV > 155 cm/s, or carotid index > 10 indicated a residual lumen diameter of < or = 1.5 mm (specificity of 100% and sensitivity of 58%, 63%, and 30%, respectively). When these criteria were combined, the sensitivity increased to 72%. A PSV > 200 cm/s combined with either an EDV > 140 cm/s or a carotid index > 4.5 has a sensitivity of 96% and a specificity of 61%., Conclusions: Doppler criteria can be both specific and sensitive for detecting a significant stenosis, defined as a < or = 1.5 mm residual lumen diameter. By adjustment of the velocity criteria, it can be 100% specific or a highly sensitive test (96%).

Objective: To evaluate the use of an anterior, transfacial transclival approach to midline posterior circulation aneurysms in five patients., Surgical Approach: A skin incision is made on the right side of the nose with subsequent bony and cartilaginous disarticulation of the nasal complex. The nose remains attached along the left side and is reflected laterally. Removal of the nasal septum and bilateral ethmoidectomy, medial maxillectomy (usually bilateral), and opening of the sphenoid yield a large triangular exposure of the anterior clivus. After removal of the clivus with a drill, the vertebral and basilar arteries are exposed through a midline dural opening., Results: The approach provided excellent exposure of basilar artery trunk aneurysms with room available for temporary clip placement in three patients. In a fourth patient, a midline posterior inferior cerebellar artery aneurysm was clipped using this technique. A basilar trunk dissection was treated by proximal basilar occlusion through this exposure in a fifth patient. Although three patients developed transient cerebrospinal fluid leaks with symptoms of meningitis, no permanent neurological morbidity resulted from the use of the approach., Conclusion: The transfacial transclival approach to midline aneurysms of the basilar trunk and its branches provided excellent exposure for surgical treatment in five patients. No patient had postoperative palatal dysfunction and cosmetic results were excellent. Cerebrospinal fluid leak and meningitis continue to be the major drawbacks to the use of this approach, although the availability of modern broad-spectrum antibiotics lessens the chance of permanent neurological sequelae.

Objective and Importance: Distal basilar artery aneurysms represent 5 to 8% of intracranial aneurysms. It is crucial to preserve all of the basilar apex perforating vessels when dissecting in this region. This report is the first to describe a rostral basilar perforating artery that was the anatomic origin of a cerebral aneurysm., Clinical Presentation: A 56-year-old woman presenting with subarachnoid hemorrhage underwent initial four-vessel cerebral angiography that did not demonstrate the source of her hemorrhage. A follow-up cerebral angio-gram 9 days later suggested a small aneurysm in the region of the left superior cerebellar artery., Intervention: A left pterional craniotomy was performed. An aneurysm arising from the origin of a distal basilar perforating artery was identified and obliterated with a small vascular clip. Flow was preserved in the perforating vessel, and the patient had an excellent outcome., Conclusion: The findings in the report illustrate the novel anatomic principle that a distal basilar perforating vessel can serve as the anatomic origin of a cerebral aneurysm. Knowledge of this entity would be helpful in avoiding complications at surgery, including perforator injury or aneurysmal rupture in such cases.

A rabbit model of focal temporary ischemia was used to test the protection provided by mild hypothermia, hypertension, mannitol and the combination of the three methods. Twenty-four New Zealand White rabbits were divided into five groups as follows: a control group, a hypertension group (mean arterial blood pressure increased by 42 mm Hg), a hypothermic group (rectal temperature decreased by 6 degrees C), a mannitol group (1 g/kg of body weight, administered intravenously), and the triple-therapy group. The intracranial internal carotid artery, the middle cerebral artery, and the anterior cerebral artery were clipped for 2 hours and then underwent 4 hours of reperfusion. Blood pressure, rectal and brain temperature, blood glucose level, hematocrit, and arterial blood gases were monitored during the experiment. For measuring the infarction size, the brain was divided into 4-mm slices and stained with 2,3,5-triphenyltetrazolium chloride. The severity of the neuronal damage was also evaluated by conventional histological examination with hematoxylin and eosin staining. The infarct volume was 193.2 +/- 34.8 (standard error of the mean) mm3 for the control group, 32.3 +/- 22.6 mm3 for the hypertension group (P < 0.0005 versus control), 40.9 +/- 17.6 mm3 for the hypothermia group (P < 0.0005), 58.0 +/- 41.0 mm3 for the mannitol group (P < 0.005), and 0.9 +/- 0.9 mm3 for the triple-therapy group (P < 0.0001). The infarct volume of the triple-therapy group was smaller than that of the hypertension, hypothermia, and mannitol groups but the difference was not statistically significant. The combination of hypertension, mild hypothermia, and mannitol to protect against temporary focal ischemia provides a set of manipulations that is readily available for neurovascular procedures.

We report a case of chiasmal apoplexy due to a cavernous malformation (CM). Surgery was delayed because of the patient's advanced pregnancy, and nearly complete recovery of vision occurred spontaneously. Recurrent hemorrhage prompted surgical extirpation. The patient was left with a residual deficit. The literature pertaining to chiasmal apoplexy and CMs is reviewed. Nearly half of the reported cases of chiasmal CM had recurrent hemorrhages. The co-occurrence of hemorrhage from CM and pregnancy is too rare to merit any conclusions about cause and effect.

Temporary vessel occlusion is an effective technique used by microvascular surgeons to facilitate dissection and permanent clipping of cerebral aneurysms; however, several questions remain regarding the overall safety of this technique. To identify technical and patient-specific risk factors for perioperative stroke, the authors examined a series of patients in whom induced hypertension and mild hypothermia and intravenous mannitol administration were used as protection during temporary vessel occlusion for aneurysm clipping. The study comprises a nonconcurrent prospective analysis of 132 consecutive aneurysm clippings performed with the aid of temporary vascular occlusion and a specific antiischemic anesthetic protocol at the Massachusetts General Hospital from 1991 to 1993. Factors studied included duration of the temporary clip application, number of occlusive episodes, patient age and neurological status, presence of preoperative subarachnoid hemorrhage (SAH), and intraoperative aneurysm rupture ("forced" temporary clipping), as well as whether proximal vessel occlusion or complete aneurysm trapping was used. In a univariate analysis, patient age, intraoperative aneurysm rupture, temporary clipping lasting more than 20 minutes, clipping between the 4th and 10th day after SAH, and multiple clipping episodes were all significantly associated with stroke outcome. Multivariate logistic regression revealed that intraoperative aneurysm rupture (relative risk 5.6, p = 0.02) and a duration of temporary clip application that lasted more than 20 minutes (relative risk 9.4, p = 0.04) were independently associated with stroke outcome. Overall, 5.2% of the patients had postoperative clinical strokes. Based on their findings the authors conclude that temporary clipping is a safe adjunct to aneurysm surgery, particularly when the duration of clipping is short.

The authors report findings from a metaanalysis of all published randomized trials of prophylactic nimodipine used in patients who have experienced subarachnoid hemorrhage (SAH). Seven trials were included with a total of 1202 patients suitable for evaluation. Eight outcome measures were examined, including good versus other outcome, good or fair outcome versus other outcome, overall mortality, deficit and/or death attributed to vasospasm, infarction rate as judged by computerized tomography (CT), and deficit and/or death from rebleeding. Nimodipine improved outcome according to all measures examined. The odds of good and of good plus fair outcomes were improved by ratios of 1.86:1 and 1.67:1, respectively, for nimodipine versus control(p<0.005 for both measures). The odds of deficit and/or mortality attributed to vasospasm and CT-assessed infarction rate were reduced by ratios of 0.46:1 to 0.58:1 in the nimodipine group (p<0.008 for all measures). Overall mortality was slightly reduced in the nimodipine group, but the trend was not statistically significant. The rebleeding rate was not increased by nimodipine. A metaregression yielded findings indicating that the treatment effect of nimodipine in individual trials was positively correlated with the severity of SAH in enrolled patients. Although the majority of individual trials examined did not have statistically significant results at the p<0.01 level according to most outcome measures, the metaanalyses confirmed the significant efficacy of prophylactic nimodipine in improving outcome after SAH under the conditions used in these trials.

The location of the carotid artery bifurcation and the distance atherosclerotic disease extends distally in the internal carotid artery (ICA) are two factors that contribute to the technical difficulty of carotid endarterectomy. When the bifurcation is high (above C-3) or the disease extends distally, standard approaches may not provide adequate exposure for dissection of plaque or for arteriotomy repair. A simple method of mandibular subluxation is described for added exposure of the distal carotid artery. The criteria for use of this method include: a carotid bifurcation at or above C-2; disease extending to within 2 cm of the skull base; and a small-caliber distal ICA lumen with the expectation of a patch graft extending close to the skull base. In dentulous patients, the mandible is subluxed by attaching an intradental wire from the ipsilateral mandibular bicuspid to an intradental wire around the contralateral maxillary bicuspid. In edentulous patients, a wire is placed around the ipsilateral mandible and secured to a wire placed through the anterior nasal spine. The entire preoperative subluxation requires 10 to 15 minutes under anesthesia and an additional 1 to 2 minutes postoperatively to remove the wires. A single skin suture and an absorbable intraoral suture were placed in some edentulous patients. This technique has been evaluated over a 15-month reference period during which 115 carotid endarterectomies were performed. The criteria stated above were met in seven cases (six patients, 6%) and jaw subluxation was performed preoperatively. An additional 1 to 2 cm of distal exposure was obtained by using this technique and endarterectomy proceeded without complication. A slight "shift" of the standard anatomical landmarks occurred due to the movement of the mandible, which was easily recognized. There were no significant postoperative complaints related to the subluxation; specifically, no temporomandibular joint pain, no other postoperative pain, and no tooth damage were encountered. It is concluded that this relatively simple approach to mandibular subluxation provided significant added exposure to the distal ICA without notably increasing operative time. In addition, there was no morbidity and little additional care was needed when compared with other more radical approaches to high carotid artery exposure.

The source of bleeding remains obscure in most cases of subarachnoid hemorrhage (SAH) with a negative angiogram. From January 1, 1989, to July 1, 1993, 40 patients were admitted to the Massachusetts General Hospital with angiogram-negative SAH; 9 of these patients underwent surgical exploration. In seven of these explorations, an arterial source of the hemorrhage was discovered. These arterial sources included three anterior communicating artery complex lesions, two middle cerebral artery lesions, one internal carotid artery aneurysm arising at the origin of the posterior communicating artery, and one vertebral/posterior inferior cerebellar artery aneurysm. Three of these seven lesions had small aneurysmal sacs, but the other four were microaneurysms too small to accept a surgical clip. No source of hemorrhage could be found during surgery on one patient with a perimesencephalic pattern of blood. Two of the four patients with a microaneurysmal source of hemorrhage had two episodes of SAH. We propose that microaneurysms are the source of a significant percentage of nonperimesencephalic angiogram-negative SAH and suggest that these lesions may represent a forme fruste of saccular aneurysms. These findings lead us to propose a protocol for the management of angiogram-negative SAH based on the distribution of blood as seen on the patient's first computed tomogram.

Background and Purpose: Although there is much speculation regarding the source of bleeding in patients with subarachnoid hemorrhage when no angiographic abnormality is found, little direct evidence has been obtained to document a cause. We report two cases of stroke in the distribution of a perforating or lenticulostriate artery occurring at the time of angiogram-negative subarachnoid hemorrhage., Case Descriptions: A 68- and a 60-year-old man each presented with acute onset of headache and meningismus. Computed tomography (CT) revealed subarachnoid hemorrhage in a perimesencephalic pattern and in the left sylvian fissure, respectively. In both instances, immediate CT revealed evidence of an early infarction in the distribution of a perforating artery originating at the site of the subarachnoid blood. Both of these strokes were demonstrated to be acute by evolution on serial imaging studies. No source for the subarachnoid blood could be found in either patient in cerebral angiograms repeated at 2 weeks., Conclusions: These observations suggest that in some cases of angiogram-negative subarachnoid hemorrhage the source of blood may be a small artery that is obliterated at the time of hemorrhage. This observation provides an explanation for the low rate of rehemorrhage among patients with angiogram-negative subarachnoid hemorrhage.

Using standard immunohistochemical techniques and an improved procedure for whole-mount vascular preparations, the authors describe the pattern and density of innervation of calcitonin gene-related peptide (CGRP)-like, neuropeptide Y (NPY)-like and vasoactive intestinal polypeptide (VIP)-like immunoreactivity in major arteries of postmortem adult human circles of Willis. Calcitonin gene-related peptide-, NPY-, and VIP-LI exhibited a variety of varicose and nonvaricose single axons, and small and large perivascular nerve bundles. Although the density of innervation within each vascular segment was highly variable, the pattern of innervation for each neuropeptide observed was consistent throughout the circle of Willis. With the use of human and rat circles of Willis as positive control preparations, the lack of CGRP-LI, NPY-LI, and VIP-LI in vessel segments taken from five cases of intracranial arteriovenous malformations (AVMs) is also reported. It is concluded that adult human circles of Willis exhibit CGRP-LI, NPY-LI, and VIP-LI perivascular nerves. In addition, intracranial AVMs do not possess these peptide-containing nerves that, in animals, normally mediate neurogenic control in the cerebrovasculature. It is hypothesized that this lack of innervation, and hence neurotrophic influence, may contribute to the development of AVMs.

This study examines the effects of alterations in nitric oxide (NO) production on rabbit retinal function. NG-nitro-L-arginine (L-NA) and L-arginine (L-Arg) inhibited the light-evoked compound action potentials (CAPs) from the optic nerve, but not the electroretinogram (ERG), in a concentration-dependent manner, whereas D-arginine had no effect. L-Arg partially reversed the L-NA-induced inhibitory effect, and L-NA prevented the L-Arg-induced attenuation of the CAPs. Sodium nitroprusside reduced both the CAPs and the ERG, whilst potassium ferricyanide did not affect the CAPs, and potentiated the ERG. We conclude that, independent of the vasculature, endogenous NO modulates neurotransmission (i.e. light-evoked CAPs), but probably not phototransduction (i.e. light-evoked ERG) in this intact in vitro central nervous system preparation.

Transient mutism resolving to cerebellar speech after posterior fossa surgery is a well-recognized phenomenon, particularly in pediatric patients. The anatomic basis for this postoperative functional change is unclear but may reside in the dominant superior cerebellar hemisphere or the medial deep cerebellar nuclei. We report a case of an 8-year-old girl who presented for surgical resection of a cavernous malformation of the right pons (at the level of the middle cerebellar peduncle) after hemorrhage. Preoperatively, her complaints consisted of contralateral motor deficits. She had normal speech. Her lesion was resected through a subtemporal approach to the pons. She awoke unable to speak. She was able to communicate through a variety of verbal cues, including sign language. Her mutism lasted 12 days after which she underwent a prolonged period of slowly resolving cerebellar dysarthria. Her preoperative motor deficits also slowly resolved. This is the first reported case of mutism resolving to cerebellar dysarthria after a supratentorial approach to the brain stem. We discuss the anatomic basis for postoperative mutism in light of previous observations combined with the unusual finding of mutism after pontine surgery. In particular, reports of mutism after bilateral cerebellar hemispheric injury, bilateral or unilateral medial deep nuclear injury, and, now, pontine tegmental injury implicate the superior cerebellar hemispheres, the deep cerebellar nuclei, and the nuclear outflow through the superior cerebellar peduncle as the anatomic bases for cerebellar participation in the production of human speech.

Reduction cranioplasty can greatly improve the quality of life for selected patients with severe macrocephaly and can significantly diminish some of the difficulties in the long-term chronic care of others. Because of differences in age, cranial morphology and surgical goals, the surgical plan must be tailored to the individual patient. Three techniques for reduction cranioplasty, with the advantages and disadvantages of each, are described. Four patients, representing the spectrum of severe macrocephaly and also the problems associated with reduction cranioplasty, are presented. Surgical indications, tactical considerations and risks are discussed.

Background: Middle cerebral artery (MCA) aneurysms are typically approached surgically using one of three basic techniques. The sylvian fissure can be opened in one of two ways; either from medial to lateral or from lateral to medial. Alternatively, an incision in the superior temporal gyrus with subpial resection can be used to expose the MCA branches and aneurysm neck., Methods: We reviewed 65 middle cerebral aneurysms in 62 patients operated on over a 5-year interval where a choice of operative approach was made based on preoperative evaluation of available radiological studies., Results: The superior temporal gyrus was used when intraparenchymal hematoma was present in the temporal lobe or when the length of the middle cerebral artery trunk was long (average length 2.44 +/- 0.41 SE cm). This approach was used in 20 operations on 22 aneurysms. The sylvian fissure approach was used in cases where the middle cerebral artery main trunk was short (1.32 +/- 0.41 SE cm) or the direction of the aneurysm was favorable. This approach was used in 38 operations. In 4 operations (5 aneurysms) we combined the two approaches to remove clot, obtain adequate exposure, and secure control of the proximal MCA., Conclusions: In most cases of MCA aneurysms the decision as to which surgical approach to use is made preoperatively depending on the presence of intraparenchymal clot, size of aneurysm, direction of aneurysm, and length of the proximal middle cerebral artery.