Neurosurgery Blog

Acta Neurochir (2010) 152:1043–1053. DOI 10.1007/s00701-010-0604-y

Meckel’s Cave may be accessed percutaneously through the foramen ovale (FO). Detailed knowledge of the region’s anatomical surroundings is invaluable in improving target accuracy and preventing complications with this approach. The approach has been used in the treatment of trigeminal neuralgia as well as in performing biopsies of lesions located in the parasellar region, described formerly by the senior author (M.S.). A comprehensive cadaveric study of the region traversed by needle is thus presented.

Materials and methods Three cadaveric heads (six sides) were fixed in formaldehyde and injected with latex. A detailed description of the regional anatomical needle trajectories was performed.

Results An “inverted pyramid” subdivided into three segments is described. The inferior third begins at cutaneous penetration and ends at the parotid duct (PD). The middle third extends from the PD to the lateral pterygoid muscle (LPM). The superior third starts from the LPM and ends at the FO. The main vascular anatomical variation was with regard to the maxillary artery (MA). In half of the cases, the MA traveled though the middle of the pyramid and in the other half through the upper third.

Conclusions Although widely used, the FO approach carries risks. Special attention is warranted when the needle traverses the upper third of the pyramid to avoid the variant course of the MA. Image-guided techniques and detailed anatomical knowledge are necessary to expand the use of this route not just for approach to lesions within the parasellar and upper third of the petroclival region but also to lesions invading the infratemporal fossa.

Neurosurgery 67:16-26, 2010 DOI: 10.1227/01.NEU.0000370008.04869.BF

This is the largest contemporary series of distal posterior cerebral artery (PCA) aneurysms treated by use of endovascular coiling and stenting as well as surgical clipping, clip wrapping, and bypass techniques. We propose a new treatment paradigm.

METHODS:The location, size, type of aneurysm, clinical presentation, treatment, complications, and outcomes associated with 34 distal PCA aneurysms in 33 patients (15 females, 18 males; mean age, 44 years) were reviewed retrospectively.

RESULTS: The most common presenting symptom was headache in 19 (58%) followed by contralateral weakness or numbness in 6 (18%) and visual changes in 4 (12%). Eight aneurysms were giant. Of the remaining 26 aneurysms, 17 were fusiform/dissecting, 5 were saccular, and 4 were mycotic. Treatment was primarily endovascular in 22 patients, 12 of whom also had a concomitant surgical bypass procedure. Nine patients underwent microsurgical clipping, and 3 underwent combined treatment of clipping and coiling and/or stenting. There were no significant differences in outcomes between the groups (P = .078). The recurrence rate in patients undergoing coiling was 22% and 0% in patients undergoing clipping. Fourteen aneurysms (41%) involved treatment with an occipital artery-to-PCA bypass or an onlay graft. Compared with their preoperative status, these patients had significantly worse outcomes than those without a bypass (P = .013).

CONCLUSION: Bypass techniques for the treatment of distal PCA aneurysms are associated with a higher rate of complications than once thought. In our new treatment paradigm, bypass is a last resort and reserved for patients in whom balloon-test occlusion fails, who refuse parent-vessel sacrifice, and who cannot undergo primary stenting with coiling or clip wrapping.

Neurosurg Focus 28 (6):E5, 2010. DOI: 10.3171/2010.3.FOCUS1032

Anterior cervical discectomy and fusion had been considered a safe and effective procedure for radiculopathy and myelopathy in the cervical spine, but degeneration in adjacent spinal levels has been a problem in some patients after fusion. Since 2002, cervical disc arthroplasty has been established as an alternative to fusion. The objective of this study was to review data concerning the role of cervical arthroplasty in reducing adjacent-level degeneration.

Methods. A systematic review was performed using the MEDLINE, EMBASE, Cochrane, and LILACS databases, focusing on a structured question involving the population of interest, types of intervention, types of control, and outcomes studied.

Results. No study has specifically compared the results of arthroplasty with the results of fusion with respect to the rate of postoperative development of adjacent-segment degenerative disease. One paper described a rate for adjacent-level surgery. The level of evidence of that paper was classified 2b, and although its authors found a statistically significant between-groups difference (arthroplasty vs fusion) using log-rank analysis, re-analysis according to number needed to treat (in the current paper) did not reveal statistical significance.

Conclusions. Adjacent-level degeneration has not been adequately studied in a review of the available randomized controlled trials on this topic, and there is no clinical evidence of reduction in adjacent-level degeneration with the use of cervical arthroplasty.

Neurosurg Rev (2010) 33:271–285. DOI 10.1007/s10143-010-0266-5

The exact pathogenesis of syringomyelia associated with Chiari type 1 malformation is unknown, although a number of authors have reported their theories of syrinx formation. The purpose of this review is to understand evidences based on the known theories and to create a new hypothesis of the pathogenesis. We critically review the literatures on clinicopathological, radiological, and clinical features of this disorder.

The previously proposed theories mainly focused on the driven mechanisms of the cerebrospinal fluid (CSF) into the spinal cord. They did not fully explain radiological features or effects of surgical treatment such as shunting procedures.

Common findings of the syrinx in clinicopathological studies were the communication with the central canal and extracanalicular extension to the posterior gray matter. Most of the magnetic resonance imaging studies demonstrated blockade and alternated CSF dynamics at the foramen magnum, but failed to show direct communication of the syrinx with the CSF spaces.

Pressure studies revealed almost identical intrasyrinx pressure to the subarachnoid space and decreased compliance of the spinal CSF space.

Recent imaging studies suggest that the extracellular fluid accumulation may play an important role. The review of evidences promotes a new hypothesis of syrinx formation. Decreased absorption mechanisms of the extracellular fluid may underlie the pathogenesis of syringomyelia. Reduced compliance of the posterior spinal veins associated with the decreased compliance of the spinal subarachnoid space will result in disturbed absorption of the extracellular fluid through the intramedullary venous channels and formation of syringomyelia.

Neurosurgery 66[ONS Suppl 2]:onsE336-onsE338, 2010 DOI: 10.1227/01.NEU.0000369644.26132.56

Currently, there is an ongoing debate regarding the best treatment option for ruptured aneurysms. The International Subarachnoid Aneurysm Trial study suggests that an endovascular procedure is the best treatment. In some complex cases, or in patients with an additional large intracerebral hemorrhage, aneurysms require further microsurgical clipping.

OBJECTIVE:We introduce a new clip system to improve clipping procedures in especially complex aneurysms.

METHODS: The inverted opening mechanism of the clip in combination with the special clip applier provides the surgeon with a good overview in the operating field. The new design also enables a wider opening of the clip jaws in contrast to all other well-known titanium aneurysm clips. This should provide a better and safer application and decrease the danger of premature rupture.

RESULTS: From January 2006 to July 2008, 55 aneurysms were clipped in 45 patients. The most common aneurysm location was the anterior communicating artery (20 patients) followed by the M1 segment of the middle cerebral artery (16 patients). Four patients had 2, one had 3, and one had 5 aneurysms. Two clipping procedures were performed for an ateriovenous malformation-associated aneurysm. All aneurysms were clipped without any technical complication.

CONCLUSION: The use of the new clip system, especially in complex aneurysm surgery, has potential benefits because of the better surgical vision during clip application and the wider opening of the clip jaws. It is easy to handle and compatible with magnetic resonance imaging.

J Neurosurg 112:1333–1339, 2010. DOI: 10.3171/2009.10.JNS09348

J Neurosurg 112:1283–1288, 2010.DOI: 10.3171/2009.10.JNS09917

Parkinson disease (PD) is often accompanied by various postural abnormalities such as camptocormia (bent spine) or Pisa syndrome (lateral flexion). The authors studied the effect of subthalamic nucleus deep brain stimulation (STN DBS) on postural abnormality in patients with PD.

Methods. The authors retrospectively reviewed the clinical course of 18 patients who suffered from significant postural abnormality and underwent bilateral STN DBS. Patients whose preoperative posture score (Unified Parkinson’s Disease Rating Scale III, item 28) was 2 or more in the “medication-on” state were enrolled in this study. Eight patients were considered to have camptocormia, and 10 patients were considered to have so-called Pisa syndrome. Nine patients showed apparent thoracolumbar spinal deformity on radiography. Most patients had significant motor fluctuations from levodopa.

Results. In 13 patients with moderate postural abnormality (score of 2 on item 28), 9 patients improved soon after surgery, but 1 patient relapsed. Two patients improved gradually over a long period after surgery, whereas 2 patients did not improve at all. In 5 patients with severe postural abnormality (score of 3 or 4 on item 28), 2 patients improved slightly in the long-term follow-up period after surgery, but 3 patients did not improve at all.

Conclusions. Postural abnormality in patients with PD could be ameliorated by STN DBS, and therefore surgery should be considered before irreversible spinal deformity develops

Acta Neurochir (2010) 152:1015–1020. DOI 10.1007/s00701-010-0629-2

The endoscopic endonasal transsphenoidal approach (EETA) to the pituitary is performed by ear, nose, and throat (ENT) surgeons in collaboration with neurosurgeons but also by neurosurgeons alone even though neurosurgeons have not been trained in rhinological surgery.

Purpose To register the frequency of endonasal anatomical variations and to evaluate whether these variations hinder the progress of EETA and require extra rhinological surgical skills.

Methods A prospective cohort study of 185 consecutive patients receiving an EETA through a binostril approach was performed. All anatomical endonasal variations were noted and the relevance for the progress of surgery evaluated.

Results In 48% of patients, anatomical variations were recognized, the majority of which were spinae septi and septum deviations. In 5% of patients, the planned binostril approach had to be converted into a mononostril approach; whereas in 18% of patients with an anatomical variation, a correction had to be performed. There was no difference between the ENT surgeon and the neurosurgeon performing the approach. Complications related to the endonasal phase of the surgery occurred in 3.8%. Fluoroscopy or electromagnetic navigation has been used during 6.5% of the surgeries.

Conclusion Although endonasal anatomical variations are frequent, they do not pose a relevant obstacle for EETA.

Acta Neurochir (2010) 152:989–995. DOI 10.1007/s00701-010-0605-x

Purpose: In patients with idiopathic normal pressure hydrocephalus (iNPH) and ventriculomegaly, examine whether there is a gradient in pulsatile intracranial pressure (ICP) from within the cerebrospinal fluid (CSF) of cerebral ventricles (ICPIV) to the subdural (ICPSD) compartment. We hypothesized that pulsatile ICP is higher within the ventricular CSF.

Methods The material includes 10 consecutive iNPH patients undergoing diagnostic ICP monitoring as part of pre-operative work-up. Eight patients had simultaneous ICPIV and ICPSD signals, and two patients had simultaneous signals from the lateral ventricle (ICPIV) and the brain parenchyma (ICPPAR). Intracranial pulsatility was characterized by the wave amplitude, rise time, and rise time coefficient; static ICP was characterized by mean ICP.

Results None of the patients demonstrated gradients in pulsatile ICP, that is, we found no evidence of higher pulsatile ICP within the CSF of the cerebral ventricles (ICPIV), as compared to either the subdural (ICPSD) compartment or within the brain parenchyma (ICPPAR). During ventricular infusion testing in one patient, the ventricular ICP (ICPIV) was artificially increased, but this increase in ICPIV produced no gradient in pulsatile ICP from the ventricular CSF (ICPIV) to the parenchyma (ICPPAR).

Conclusions: In this cohort of iNPH patients, we found no evidence of transmantle gradient in pulsatile ICP. The data gave no support to the hypothesis that pulsatile ICP is higher within the CSF of the cerebral ventricles (ICPIV) than within the subdural (ICPSD) compartment or the brain parenchyma (ICPPAR) in iNPH patients.

Neurosurg Q 2010;20:107–110

Objective: To assess the safety and efficacy of outpatient anterior cervical discectomy and fusion (ACDF) carried out on outpatients.

Methods: We retrospectively reviewed the records of 390 consecutive patients who underwent outpatient ACDF between September 2002 and September 2007 to assess the safety and efficacy of outpatient anterior cervical surgery. The mean age of the patient sample was 46; 56% were female and 44% were male. Indications for surgery consisted of cervical radiculopathy or myelopathy. Charts were reviewed to define patient demographics and medical comorbidities. Operative data, including levels treated, surgery time, time to discharge, and intraoperative complications were collected. Clinical outcomes were collected using the PhDx Clinical Outcomes Database. Need for hospital transfer from the ambulatory surgical center, emergency room visits, and subsequent hospital admission in the perioperative period were determined from patient records. Complications, patient satisfaction, and outcome were ascertained through review of notes from the first postoperative visit.

Results: There was no mortality and there were no major complications. Out of 390 patients, operation was carried out at 1 level in 223 patients, at 2 levels in 143, and at 3 levels in 24. Pain was present in 99%, motor deficit in 31%, and myelopathy in 14%. Twenty-five percent were hypertensive, 5% were diabetic, and 2% had coronary artery disease. The incidence of hospital transfer for ACDF related complications was <1%, emergency room visits <1% and subsequent hospitalization <1%. At the time of the first postoperative visit 92% of patients believed that they were improved and only 1% of patients had transiently increased radicular weakness.

Conclusion: Outpatient ACDF is safe and efficacious in selected patients.

J Neurooncol (2010) 98:195–202. DOI 10.1007/s11060-010-0173-1

One hundred and seventeen patients with cavernous sinus meningiomas had LINAC radiosurgery at our institution in the period 1993–2007. Six cases were lost and 9 had less than 1 year follow up. The remaining 102 patients were prospectively followed up at 1 y intervals with clinical, neuro-ophthalmological and MRI examinations. Patients’ age ranged between 31 and 86 years (mean 57). Seventy percent were females. The mean tumor volume was 7 cc. Thirty-three patients had previous microsurgery. Tumors were defined with high resolution MRI obtained 1–2 days before treatment and fused to stereotactic CT. Treatment was mostly delivered through a minimultileaf collimator and multiple dynamic arcs. The minimal dose to the tumor margin was 12–17.5 Gy (mean 13.5) encompassed by the 80% isodose shell. Radiation dose to the optic apparatus was kept below 10 Gy. Follow up ranged from 12 to 180 months (mean 67 months). Tumor control (lack of growth) was 98% (58% of the tumors reduced their volumes). Sixty-four patients presented with cranial nerve deficit. Thirty-nine percent improved or resolved following radiosurgery. Cranial neuropathy had significantly higher resolution rates when radiosurgery was performed early (\1 year) after its appearance (53% as opposed to 26%) even in patients with deficits post surgery. Complications were seen in five patients (1 with deafferentation pain, 1 with facial hypesthesia, 1 with visual loss and 2 with partial VI neuropathy). Radiosurgery had a high control rate for meningiomas of the cavernous sinus with few and mild complications. Cranial neuropathy can be solved by treatment, particularly those of recent onset.

Childs Nerv Syst (2010) 26:791–796. DOI 10.1007/s00381-009-1061-x

The reported rate is up to 10% of shunt disconnection or fracture, either ventriculoperitoneal or subduroperitoneal. However, not all of shunt discontinuity is associated with shunt malfunction. We analyzed the discontinuity of the shunt system and related factors and tried to present a follow-up policy.

Methods This is a retrospective study involving 22 patients who presented with shunt disconnection because of malfunction or other reasons between January 2003 and October 2008. To evaluate shunt function, we performed a shuntogram, temporary ligation, or intraoperative exploration.

Results Nine (40.9%) of 22 patients had nonfunctioning shunts. The shunt system was removed in eight cases, and one patient refused surgical management. Of these 22 patients with disconnected shunts, 17 shunts placed in the occipital area were discontinued. The discontinuations were mostly fractured at neck (52%), not disconnected at connection site.

Conclusion Shunt disconnection has not been always represented a shunt malfunction. We thought many patients with disconnected shunt may be independent from shunt system, and it can be a good chance for patient to remove the shunt system

J Neurosurg 112:1200–1207, 2010. DOI: 10.3171/2009.10.JNS08754

The aim of the study was to assess postprocedural neurological deterioration and outcome in patients older than 70 years of age in whom treatment was managed in an interdisciplinary context.

Methods. This prospective longitudinal study included all patients 70 years of age or older treated for ruptured cerebral aneurysm over 10 years (June 1997–June 2007). The population was composed of 64 patients. The neurovascular interdisciplinary team jointly discussed the early obliteration procedure for each aneurysm. Neurological deterioration during the postprocedural 2 months and outcome at 6 months were assessed during consultation according to the modified Rankin Scale (mRS) as follows: favorable (mRS score ≤ 2) and unfavorable (mRS score > 2).

Results. Aneurysm sac obliteration was performed by microvascular clipping in 34 patients (53.1%) and by endovascular coiling in 30 (46.9%). Postprocedural neurological deterioration occurred in 30 patients (46.9%), related to ischemia in 19 (29.7%), rebleeding in 1 (1.6%), and hydrocephalus in 10 (15.6%). At 6 months, the outcome was favorable in 39 patients (60.9%). By multivariate regression logistic analysis, the independent factors associated with unfavorable outcome were age exceeding 75 years (p = 0.005), poor initial grade (p < 0.0001), and the occurrence of ischemia (p < 0.0001).

Conclusions. The baseline characteristics of SAH in the elderly were only slightly different from those in younger patients. In the elderly, the interdisciplinary approach may be considered useful to decrease the ischemic consequences.

Neurosurgery 66:1153-1160, 2010 DOI: 10.1227/01.NEU.0000369189.09182.5F

A meta-analysis was performed to evaluate whether a beneficial clinical effect of cervical disk prostheses over conventional cervical diskectomy with fusion exists.

METHODS: A literature search was completed ending February 4, 2009, that included the abstract books of recent major spine congresses. All studies reported the results of singlelevel cervical disease without myelopathy. The Visual Analog Score (VAS) of the arm, VAS of the neck, Neck Disability Index, Physical Composite Scores of the Short Form 36, and Mental Composite Score of the Short Form 36, as well as adverse events, were evaluated.

RESULTS: Nine records were found, totaling 1533 patients. Of these, 1165 were evaluable at the last follow-up at 12 or 24 months. As an effect measure, a pooled odds ratio (OR) was calculated at 12 and 24 months. At 12 months, the VAS arm reached statistical significance (OR = 0.698; 95% confidence interval [CI], 0.571-0.853), as did the VAS neck (OR = 0.690; 95% CI, 0.562-0.847), and the Physical Composite Scores (OR = 1.362; 95% CI, 1.103-1.682) and the Mental Composite Score (OR = 1.270; 95% CI, 1.029-1.569) of the Short Form 36, favoring arthroplasty. The Neck Disability Index at 24 months also reached statistical difference (OR = 0.794; 95% CI, 0.641-0.984). All other measurements did not reveal any statistical difference. The number of complications, including secondary surgeries for adjacent segment disease, did not differ.

CONCLUSION: A clinical benefit for the cervical disk prosthesis is not proven. Because none of the studies were blinded, bias of the patient or researcher is a probable explanation for the differences found. Therefore, these costly devices should not be used in daily clinical practice.

Neurosurgery 66:1039-1043, 2010 DOI: 10.1227/01.NEU.0000369512.58898.99

Subarachnoid hemorrhage accounts for 2% to 5% of all strokes and is associated with high morbidity and mortality rates. Reports in the literature show that case-fatality rates vary with time and according to geographical area.

OBJECTIVE: The objective of the study was to evaluate the case-fatality rates in subarachnoid hemorrhage at 1 and 6 months and to determine trends in these rates over 22 years using a population-based registry.

METHODS: The Dijon Stroke Registry has enabled us to perform a comprehensive analysis of subarachnoid hemorrhage diagnosed in a population of >150 000 inhabitants hospitalized between 1985 and 2006 in the Dijon University Hospital, which has both a neurosurgery unit and a neuroradiology unit. Diagnosis was based on clinical and neuroimaging features and, when necessary, on lumbar puncture.

RESULTS: Case-fatality rates for hospitalized subarachnoid hemorrhages at 1 and 6 months were 15.59% (95% confidence interval [CI], 9.37-25.34) and 16.84% (95% CI, 10.33-26.78), respectively. From 1985 to 1995, case-fatality rates for SAH at 1 and 6 months were 17.1% (95% CI, 8.1-34.2) and 17.7% (95% CI, 9.6-31.3), whereas from 1996 to 2006, they were 20.2% (95% CI, 10.2-37.8) and 19.7% (95% CI, 11.1-33.6), respectively.

CONCLUSION: Case-fatality rates for hospitalized subarachnoid hemorrhages in this population- based study remained stable over 22 years, suggesting that this stroke subtype is still a very severe disease despite early management. Most deaths occurred during the first 30 days. Further work is necessary to evaluate levels of prehospital case-fatality in our population-based registry.

J Spinal Disord Tech 2010;23:229–235

Study Design: The 2 groups of patients with severe lumbar spinal stenosis were prospectively compared as a case control study.

Objectives: This prospective case control study sought to evaluate bilateral microdecompressive laminatomy (MDL) for treatment of severe lumbar spinal stenosis.

Summary of Background Data: Total laminectomy is a general consensus on the therapy of severe spinal stenosis. The authors tried to investigate a new minimal invasive approach.

Methods: Patients were randomly divided into 2 groups. In first group, 34 patients underwent total laminectomy (TL) for severe lumbar spinal stenosis. In the second group, 37 patients with the same diagnosis underwent bilateral MDL. The groups were compared for disability, walking distance, degree of postoperative back and leg pain, perioperative complications, and postoperative instability. Radiographic analyses were performed at regular intervals to demonstrate satisfactory decompression.

Results: Mean follow-up was 5 years. Postoperative computerized tomography and magnetic resonance imaging demonstrated adequate decompressions in both groups. The walking distance, pain control, and disability scores were slightly higher among patients in the MDL group, although these results did not achieve statistical significance. Perioperative complications and postoperative instability were significantly higher in the TL group (P<0.05).

Conclusions: Compared with classic approaches, bilateral MDL provides adequate and safe decompression in lumbar spinal stenosis. It significantly reduces clinical symptoms and disability. However, TL shows higher perioperative complications and postoperative instability. To the best of our knowledge, this is the first study to define a bilateral MDL approach to treat the stenotic lumbar spine without a herniated disc.

Neurosurgery 66:1128-1133, 2010 DOI: 10.1227/01.NEU.0000367998.33743.D6

To evaluate clinical presentation, safety, techniques, clinical and angiographic outcomes, and prognostic factors of coiling for remnant/recurred aneurysm after clipping.

METHODS:Twenty-four consecutive patients (11 men and 13 women; mean age, 52 years) with 24 recurred/remnant aneurysms after clipping underwent coil embolization between September 2000 and December 2008. Clinical presentations of remnant/recurred aneurysms, safety, techniques, clinical and angiographic outcomes, and prognostic factors of coil embolization were retrospectively evaluated.

RESULTS: Twenty-two aneurysms initially presented with subarachnoid hemorrhage and the other two, with mass effect. Eight aneurysms presented with rebleeding and 16 aneurysms were found on follow-up CT angiogram (n = 12) or catheter angiogram (n = 4). The interval between clipping and coiling ranged from 8 days to 114 months (mean, 31 months). Twelve were treated by using single-catheter, 6 by stent-assisted, 4 by multicatheter, 1 by both balloon- and catheter-assisted, and 1 by balloon-in-stent technique. Immediate postembolization angiogram revealed complete obliteration (n = 19) or residual neck (n = 5). Procedure-related permanent morbidity and mortality rates were 4.2% (1 of 24) and 0%, respectively. There was no rebleeding during clinical follow-up for 3 to 82 months (mean, 24 months). Presentation with rupture after clipping was the only significant predictor of poor outcome (P < .05).

CONCLUSION: Coiling seems to be a safe and effective retreatment option for remnant/ recurred aneurysm after clipping. Presentation with rupture after clipping is the only predictor of poor outcome. For routine/regular follow-up after clipping, CT angiography may be the imaging modality advisable for detection of remnant/recurred aneurysm.

Neurosurg Q 2010;20:74–81

The posterior communicating artery aneurysms correspond on 25% of all ruptured aneurysms. The clinical course is typically a subarachnoid hemorrhage and third nerve palsy. We intend to introduce a new classification for PComA aneurysms to help neurosurgeons in day-to-day practice present. We review our experience in PComA aneurysms and discuss the main factors involving morbidity, mortality, signs and symptoms, and prognosis of these aneurysms.

Material and Methods: We reviewed historical records, images, surgical videos, and CDs of 46 surgically clipped aneurysms in 39 patients from June 2000 to July 2009, in 2 Institutions: Hospital Sa˜o Camilo and Santa Paula, Sa˜o Paulo, Brazil. They were classified in 2 groups, the A group composed by patients who presented subarachnoid hemorrhage in acute phase and the B group composed by incidental aneurysms carriers. All patients were classified according to Hunt-Hess scale.

Results: The average age found was 53.6 years old (min 28 to Max 92). The incidence was higher among women (3.6:1). Worse outcomes were observed in group A. The mortality rate was 20% in group A and zero cases in group B. Similar rate was found for rupture cases (20% in A group vs zero in B group). Morbidity was similar for both groups. The mean aneurismal size for A group was 6mm (ranging from 5 to 25mm) and 5.3mm (ranging from 3 to 10 mm) for B group.

Conclusions: Posterior communicating artery aneurysms occurred 3 to 4 times more frequently in women than man. Oculomotor palsy associated with severe headache were commonly related to posterior circulation aneurysms. Type II aneurysms (temporal) were the most frequently found in our study. The worst prognosis in cases with acute bleeding occurred with fetal variant circulation. Intratentorial aneurysms, mainly those with increased Hunt-Hess, have the worst prognosis. Infundibular aneurysms had the best results with surgical clipping.

Neurosurgery 66:1074-1084, 2010 DOI: 10.1227/01.NEU.0000369514.74284.78

Awake craniotomy with intraoperative electrical mapping is a reliable method to minimize the risk of permanent deficit during surgery for low-grade glioma located within eloquent areas classically considered inoperable. However, it could be argued that preservation of functional sites might lead to a lesser degree of tumor removal. To the best of our knowledge, the extent of resection has never been directly compared between traditional and awake procedures.

OBJECTIVE: We report for the first time a series of patients who underwent 2 consecutive surgeries without and with awake mapping.

METHODS: Nine patients underwent surgery for a low-grade glioma in functional sites under general anesthesia in other institutions. The resection was subtotal in 3 cases and partial in 6 cases. There was a postoperative worsening in 3 cases. We performed a second surgery in the awake condition with intraoperative electrostimulation. The resection was performed according to functional boundaries at both the cortical and subcortical levels.

RESULTS: Postoperative magnetic resonance imaging showed that the resection was complete in 5 cases and subtotal in 4 cases (no partial removal) and that it was improved in all cases compared with the first surgery (P = .04). There was no permanent neurological worsening. Three patients improved compared with the presurgical status. All patients returned to normal professional and social lives.

CONCLUSION: Our results demonstrate that awake surgery, known to preserve the quality of life in patients with low-grade glioma, is also able to significantly improve the extent of resection for lesions located in functional regions.