Miniaturized handheld confocal imaging may assist neurosurgeons in detecting infiltrative brain tumor margins during surgery. It may help to avoid sampling error during biopsy of heterogeneous glial neoplasms, with the potential to supplement conventional intraoperative frozen section pathology. Clinical trials are warranted on the basis of these promising initial results.

The photonic bandgap fiber CO(2) laser produced reliable cortical incisions, adjustable over a range of settings, with minimal adjacent thermal tissue damage. Ease of application under the microscope suggests this laser system has reached true practicality for neurosurgery.

In this historical review the authors examine the important developments that have led to the availability of laser energy to neurosurgeons as a unique and sometimes invaluable tool. They review the physical science behind the function of lasers, as well as how and when various lasers based on different lasing mediums were discovered. They also follow the close association between advances in laser technology and their application in biomedicine, from early laboratory experiments to the first clinical experiences. Because opinions on the appropriate role of lasers in neurosurgery vary widely, the historical basis for some of these views is explored. Initial enthusiasm for a technology that appears to have innate advantages for safe resections has often given way to the strict limitations and demands of the neurosurgical operating theater. However, numerous creative solutions to improve laser delivery, power, safety, and ergonomics demonstrate the important role that technological advances in related scientific fields continue to offer neurosurgery. Benefiting from the most recent developments in materials science, current CO2 laser delivery systems provide a useful addition to the neurosurgical armamentarium when applied in the correct circumstances and reflect the important historical advances that come about from the interplay between neurosurgery and technology.

OBJECTIVERuptured blister aneurysms remain challenging lesions for treatment due to their broad, shallow anatomy and thin, fragile wall. Historical challenges with both open microsurgical approaches and intrasaccular endovascular approaches have led to increased use of flow diversion for management of these aneurysms. However, the optimum paradigm, including timing of treatment, use of dual antiplatelet therapy, and number of flow-diverter devices to use remains unknown. The authors describe their experience with ruptured blister aneurysms treated with flow diversion at their institution, and discuss rates of rebleeding and number of devices used.METHODSAll patients presenting with subarachnoid hemorrhage from a ruptured blister aneurysm and treated with Pipeline flow diversion were identified. Patient demographic data, clinical status and course, need for external ventricular drain (EVD), timing of treatment, and angiographic details and follow-up were recorded.RESULTSThere were 13 patients identified (11 women and 2 men), and 4 had multiple aneurysms. Two aneurysms were treated on initial angiography, with average time to treatment of 3.1 days for the remainder, after discussion with the family and institution of dual antiplatelet therapy. Device placement was technically successful in all patients, with 2 patients receiving 2 devices and the remainder receiving 1 device. There was 1 intraoperative complication, of a wire perforation causing intracerebral hemorrhage requiring decompressive craniectomy. Three patients had required EVD placement for management of hydrocephalus. There was no rebleeding from the target lesion; however, one patient had worsening intraventricular hemorrhage and another had rupture of an unrecognized additional aneurysm, and both died. Of the other 11 patients, 10 made a good recovery, with 1 remaining in a vegetative state. Nine underwent follow-up angiography, with 5 achieving complete occlusion, 2 with reduced aneurysm size, and 2 requiring retreatment for aneurysm persistence or enlargement. There were no episodes of delayed rupture.CONCLUSIONSPipeline flow diversion is a technically feasible and effective treatment for ruptured blister aneurysms, particularly in good-grade patients without hydrocephalus. Patients with a worse grade on presentation and requiring EVDs may have higher risk for bleeding complications and poor outcome. There was no rebleeding from the target lesion with use of a single device in this series.

During the past decade we have seen a treatment paradigm shift in MCA aneurysm treatment from surgical treatment to endovascular treatment. Developments in 3D angiography, more compliant balloons, dedicated aneurysm stents, complex coils, and antiplatelet therapy regimes have led to this transition for safe and effective management of these patients.

Background:We sought to review the current literature with regards to future risks of hemorrhage following cerebral revascularization in Moyamoya disease (MMD).Methods:We performed a comprehensive literature review using PubMed to inspect the available data on the risk of hemorrhage after revascularization in MMD.Results:In this review, we identify the risk factors associated with hemorrhage in MMD both before and after cerebral revascularization. We included proposed pathophysiology of the hemorrhagic risk, role of the type of bypass performed, treatment options, and future needs for investigation.Conclusions:The published cases and series of MMD treatment do show a risk of hemorrhage after treatment with either direct or indirect bypass both in the immediate as well as long-term future. While there are no discernible patterns in the rate of these hemorrhages, there is Class III evidence for the predictive effect of multiple microbleeds on preoperative imaging. Also, whereas revascularization, both direct and indirect, has been shown to reduce ischemic complications from MMD, there is not an association with the risk of hemorrhage after the procedure. Further studies need to be performed to help evaluate what the risk factors are and how to counsel patients as to the long-term outlook of this disease process.

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696Supratentorial gliomas are the most frequently diagnosed primary brain tumors in adults. 1 Despite representing only 1.5% of all malignancies, 2 they are a significant cause of cancerrelated death in the general population. 3 As a result, a considerable body of research has focused on identifying prognostic markers for patients with these tumors. Although no list of such markers is universally accepted, many authors consistently agree that histopathological grade, 4-7 patient age, [8][9][10][11][12] ABSTRACT: Background: Assessing the impact of glioma location on prognosis remains elusive. We approached the problem using multivoxel proton magnetic resonance spectroscopic imaging ( 1 H-MRSI) to define a tumor "metabolic epicenter", and examined the relationship of metabolic epicenter location to survival and histopathological grade. Methods: We studied 54 consecutive patients with a supratentorial glioma (astrocytoma or oligodendroglioma, WHO grades II-IV). The metabolic epicenter in each tumor was defined as the 1 H-MRSI voxel containing maximum intra-tumoral choline on preoperative imaging. Tumor location was considered the X-Y-Z coordinate position, in a standardized stereotactic space, of the metabolic epicenter. Correlation between epicenter location and survival or grade was assessed. Results: Metabolic epicenter location correlated significantly with patient survival for all tumors (r 2 = 0.30, p = 0.0002) and astrocytomas alone (r 2 = 0.32, p = 0.005). A predictive model based on both metabolic epicenter location and histopathological grade accounted for 70% of the variability in survival, substantially improving on histology alone to predict survival. Location also correlated significantly with grade (r 2 = 0.25, p = 0.001): higher grade tumors had a metabolic epicenter closer to the midpoint of the brain. Conclusions: The concept of the metabolic epicenter eliminates several problems related to existing methods of classifying glioma location. The location of the metabolic epicenter is strongly correlated with overall survival and histopathological grade, suggesting that it reflects biological factors underlying glioma growth and malignant dedifferentiation. These findings may be clinically relevant to predicting patterns of local glioma recurrence, and in planning resective surgery or radiotherapy.RÉSUMÉ: Épicentre métabolique des gliomes sustentoriels : une étude SRM 1H. Contexte : L'impact de la localisation d'un gliome sur le pronostic demeure difficile à déterminer. Nous avons abordé ce problème au moyen de l'imagerie par spectroscopie « multivoxel » par résonance magnétique de proton (SRM 1H) afin d'identifier l' « épicentre métabolique » de la tumeur et d'examiner la relation entre la localisation de l'épicentre métabolique d'une part et la survie et le grade anatomopathologique d'autre part. Méthodes : Nous avons étudié 54 patients consécutifs porteurs d'un gliome sustentoriel (astrocytome ou oligodendrogliome, grades II à IV selon la classification de l'OMS). L'épicentre métabolique de chaque...