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Surgical Approaches to the Temporal Horn: An Anatomic Analysis of White Matter Tract Interruption

Operative Neurosurgery 13:258–270, 2017

Surgical access to the temporal horn is necessary to treat tumors and vascular lesions, but is used mainly in patients with mediobasal temporal epilepsy. The surgical approaches to this cavity fall into 3 primary categories: lateral, inferior, and transsylvian. The current neurosurgical literature has underestimated the interruption of involved fiber bundles and the correlated clinical manifestations.

OBJECTIVE: To delineate the interruption of fiber bundles during the different approaches to the temporal horn.

METHODS:We simulated the lateral (trans-middle temporal gyrus), inferior (transparahippocampal gyrus), and transsylvian approaches in 20 previously frozen, formalin-fixed human brains (40 hemispheres). Fiber dissection was then done along the lateral and inferior aspects under the operating microscope. Each stage of dissection and its respective fiber tract interruption were defined.

RESULTS: The lateral (trans-middle temporal gyrus) approach interrupted “U” fibers, the superior longitudinal fasciculus (inferior arm), occipitofrontal fasciculus (ventral segment), uncinate fasciculus (dorsolateral segment), anterior commissure (posterior segment), temporopontine, inferior thalamic peduncle (posterior fibers), posterior thalamic peduncle (anterior portion), and tapetum fibers. The inferior (transparahippocampal gyrus) approach interrupted “U” fibers, the cingulum (inferior arm), and fimbria, and transected the hippocampal formation. The transsylvian approach interrupted “U”fibers (anterobasal region of the extreme capsule), the uncinate fasciculus (ventromedial segment), and anterior commissure (anterior segment), and transected the anterosuperior aspect of the amygdala.

CONCLUSION: White matter dissection improves our knowledge of the complex anatomy surrounding the temporal horn. Identifying the fiber bundles at risk during each surgical approach adds important information for choosing the appropriate surgical strategy.

 

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Reappearance of arteriovenous malformations after complete resection of ruptured arteriovenous malformations

J Neurosurg 126:1088–1093, 2017

Ruptured arteriovenous malformations (AVMs) are often obliterated after emergency microsurgical treatment. However, some studies have reported AVM recurrence after the obliteration of ruptured AVMs. The authors report their experience with AVM recurrence after successful microsurgical treatment of ruptured AVMs.

METHODS The authors reviewed the medical data of 139 consecutive patients who underwent microsurgery at the authors’ institution for ruptured AVM between 2002 and 2012. Each patient underwent a conventional cerebral angiography examination immediately after the surgery. Subsequent follow-ups were performed with MR angiography after 6 months, and, if there was no indication of AVM recurrence, patients were followed up with conventional cerebral angiography between 1 and 2 years after the treatment; pediatric patients were followed up until age 18 years. Recurrence was defined as new radiological evidence of an AVM at the site of a ruptured AVM or a new hemorrhage in patients with angiographically documented AVM obliteration on postoperative angiograms.

RESULTS The mean age of the patients at the time of ruptured AVM diagnosis was 30.8 years (SD ± 5, range 4–69 years), and 44 of the patients were younger than 18 years (the mean age at diagnosis in this pediatric subgroup was 11.4 years [range 4–17.9 years]). Complete AVM obliteration after the initial microsurgery was observed in 123 patients (89.5%). Reappearance of an AVM was noted in 7 patients between 12 and 42 months after the treatment, and all of these patients were younger than 18 years. The recurrent AVM was located in an eloquent zone in 4 patients, and deep venous drainage was noted in 3 patients. Radiosurgery was performed in 6 of these patients, and 1 patient underwent another microsurgical procedure. The authors noted only one rebleeding due to an AVM recurrence during the latency period after radiosurgery.

CONCLUSIONS The recurrence of an AVM is fairly rare and affects mostly pediatric patients. Therefore, especially in children, long-term angiographic follow-up is required to detect AVM recurrence or an AVM remnant. The authors stress the need for discussion involving a multidisciplinary neurosurgical team to decide on treatment in cases of any AVM recurrence or remnant.

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Early diffusion-weighted MRI lesions after treatment of unruptured intracranial aneurysms:

J Neurosurg 126:1070–1078, 2017

Diffusion-weighted MRI was used to assess periprocedural lesion load after repair of unruptured intracranial aneurysms (UIA) by microsurgical clipping (MC) and endovascular coiling (EC).

METHODS Patients with UIA were assigned to undergo MC or EC according to interdisciplinary consensus and underwent diffusion-weighted imaging (DWI) 1 day before and 1 day after aneurysm treatment. Newly detected lesions by DWI after treatment were the primary end point of this prospective study. Lesions detected by DWI were categorized as follows: A) 1–3 DWI spots < 10 mm, B) > 3 DWI spots < 10 mm, C) single DWI lesion > 10 mm, or D) DWI lesion related to surgical access.

RESULTS Between 2010 and 2014, 99 cases were included. Sixty-two UIA were treated by MC and 37 by EC. There were no significant differences between groups in age, sex, aneurysm size, occurrence of multiple aneurysms in 1 patient, or presence of lesions detected by DWI before treatment. Aneurysms treated by EC were significantly more often located in the posterior circulation (p < 0.001). Diffusion-weighted MRI detected new lesions in 27 (43.5%) and 20 (54.1%) patients after MC and EC, respectively (not significant). The pattern of lesions detected by DWI varied significantly between groups (p < 0.001). Microembolic lesions (A and B) found on DWI were detected more frequently after EC (A, 14 cases; B, 5 cases) than after MC (A, 5 cases), whereas C and D were rare after EC (C, 1 case) and occurred more often after MC (C, 12 cases and D, 10 cases). No procedure-related unfavorable outcomes were detected.

CONCLUSIONS According to the specific techniques, lesion patterns differ between MC and EC, whereas the frequency of new lesions found on DWI is similar after occlusion of UIA. In general, the lesion load was low in both groups, and lesions were clinically silent. Clinical trial registration no.: NCT01490463 (clinicaltrials.gov)

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Pathophysiology of Intracranial Aneurysm: The ICAN Project

Neurosurgery 80:621–626, 2017

Understanding the pathophysiologic mechanism of intracranial aneurysm
 (IA) formation is a prerequisite to assess the potential risk of rupture. Nowadays, there are neither reliable biomarkers nor diagnostic tools to predict the formation or the evolution of IA. Increasing evidence suggests a genetic component of IA but genetics studies have failed to identify genetic variation causally related to IA.

OBJECTIVE: To develop diagnostic and predictive tools for the risk of IA formation and rupture.

METHODS: The French ICAN project is a noninterventional nationwide and multicentric research program. Each typical IA of bifurcation will be included. For familial forms, further IA screening will be applied among first-degree relatives. By accurate phenotype description with high-throughput genetic screening, we aim to identify new genes involved in IA. These potential genetic markers will be tested in large groups of patients. Any relevant pathway identified will be further explored in a large cohort of sporadic carriers of IA, which will be well documented with clinical, biological, and imaging data.

EXPECTED OUTCOMES: Discovering genetic risk factors, better understanding the pathophysiology, and identifying molecular mechanisms responsible for IA formation will be essential bases for the development of biomarkers and identification of therapeutic targets.

DISCUSSION: Our protocol has many assets. A nationwide recruitment allows for the inclusion of large pedigrees with familial forms of IA. It will combine accurate phenotyping and comprehensive imaging with high-throughput genetic screening. Last, it will enable exploiting metadata to explore new pathophysiological pathways of interest by crossing clinical, genetic, biological, and imaging information.

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Craniotomy for perisellar meningiomas: comparison of simple (appropriate for endoscopic approach) versus complex anatomy and surgical outcomes

J Neurosurg 126:1191–1200, 2017

Microsurgical resection of perisellar meningiomas has remained the gold standard for treatment, with extended endoscopic endonasal surgery emerging as a viable alternative. Historical microsurgical series do not distinguish based on tumor anatomy, but are being used as a comparison against endonasal surgery. In this study, the authors retrospectively reviewed and compared the anatomy of perisellar meningiomas seen at their institution. The tumors were separated into 2 groups based on whether they would be appropriate for endoscopic resection, and the authors compared the surgical outcomes.

METHODS Between 2001 and 2013, 53 patients (73.6% women) with perisellar meningiomas underwent open microsurgical resection at Vancouver General Hospital performed by the senior author (R.A.). These tumors were separated into 2 groups based on their anatomy, and the authors analyzed the resection rates, surgical results, patient quality of life, and complications.

RESULTS Among the 53 patients who presented with perisellar meningiomas, the authors were able to identify 18 lesions with “simple” anatomy suitable for endoscopic resection and 35 lesions with “complex” anatomy suitable for craniotomy resection. The mean age of patients in the study cohort was 57.4 years (range 33–91 years), and most patients presented with visual loss (68.0%) and visual field restriction (64.2%). There were no major differences in patient demographic data between the 2 groups. Patients with simple anatomy had smaller lesions (2.1 vs 3.5 cm; p = 0.004), no optic canal invasion (89% vs 26%; p < 0.0001), minimal vascular encasement (cortical cuff 83% vs 9%; p < 0.0001), and a rounded tumor shape (100% vs 31.8%; p = 0.0001) when compared with those with complex anatomy. The majority of lesions originated from the tuberculum sellae and planum sphenoidale. A greater degree of resection was achieved in the favorable anatomy group (99% vs 87.1%; p < 0.0001). Vision was improved or normalized in 96.6% of patients. Patients in the cohort with complex anatomy had more transient complications; there were no incidents of surgical-site infection, meningitis, or death in this series. One patient who underwent removal of a recurrent lesion experienced a CSF leak that required endoscopic repair. The overall persisting complications rate was higher in the group with complex anatomy (11.1% vs 37.1%; p = 0.0498); overall, 28.3% of patients experienced disabling complications. Patient-perceived quality of life improved in the simple anatomy group following surgery (DSF-36 +16.6 vs -8.4; p = 0.0045).

CONCLUSIONS Extended endoscopic surgery is emerging as a viable alternative to microsurgical resection of perisellar meningiomas. The authors identified 2 patient groups based on tumor anatomy, with distinctly separate surgical outcomes. In the future, patients considered for endoscopic resection should be compared against the surgical group with simple anatomy that includes smaller tumors, no vascular encasement, and limited optic canal invasion.

 

 

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Hemorrhage from cerebral cavernous malformations

J Neurosurg 126:1079–1087, 2017

The aim of this paper is to define an overall cavernous malformation (CM) hemorrhage rate and risk factors for hemorrhage.

METHODS The authors performed a systematic, pooled analysis via the PubMed database through October 2015 using the terms “cavernoma,” “cavernous malformation,” “natural history,” “bleeding,” and “hemorrhage.” English-language studies providing annual rates and/or risk factors for CM hemorrhage were included. Data extraction, performed independently by the authors, included demographic data, hemorrhage rates, and hemorrhage risk factors.

RESULTS Across 12 natural history studies with 1610 patients, the mean age at presentation was 42.7 years old and 52% of patients (95% CI 49%–55%) were female. Presentation modality was seizure in 30% (95% CI 25%–35%), hemorrhage in 26% (95% CI 17%–37%), incidental in 17% (95% CI 9%–31%), and focal deficits only in 16% of cases (95% CI 11%–23%). CM location was lobar in 66% (95% CI 61%–70%), brainstem in 18% (95% CI 13%–24%), deep supratentorial in 8% (95% CI 6%–10%), and cerebellar in 8% (95% CI 5%–11%). Pooling 7 studies that did not assume CM presence since birth, the annual hemorrhage rate was 2.5% per patient-year over 5081.2 patient-years of follow-up (95% CI 1.3%–5.1%). Pooling hazard ratios across 5 studies that evaluated hemorrhage risk factors, prior CM hemorrhage was a significant risk factor for hemorrhage (HR 3.73, 95% CI 1.26–11.1; p = 0.02) while younger age, female sex, deep location, size, multiplicity, and associated developmental venous anomalies (DVAs) were not.

CONCLUSIONS Although limited by the heterogeneity of incorporated reports and selection bias, this study found prior hemorrhage to be a significant risk factor for CM bleeding, while age, sex, CM location, size, multiplicity, and associated DVAs were not. Future natural history studies should compound annual hemorrhage rate with prospective seizure and nonhemorrhagic neurological deficit rates.

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Transtentorial transcollateral sulcus approach to the ventricular atrium

J Neurosurg 126:1246–1252, 2017

Conventional approaches to the atrium of the lateral ventricle may be associated with complications related to direct cortical injury or brain retraction. The authors describe a novel approach to the atrium through a retrosigmoid transtentorial transcollateral sulcus corridor.

METHODS: Bilateral retrosigmoid craniotomies were performed on 4 formalin-fixed, colored latex–injected human cadaver heads (a total of 8 approaches). Microsurgical dissections were performed under 3× to 24× magnification, and endoscopic visualization was provided by 0° and 30° rigid endoscope lens systems. Image guidance was provided by coupling an electromagnetic tracking system with an open source software platform. Objective measurements on cortical thickness traversed and total depth of exposure were recorded. Additionally, the basal occipitotemporal surfaces of 10 separate cerebral hemisphere specimens were examined to define the surface topography of sulci and gyri, with attention to the appearance and anatomical patterns and variations of the collateral sulcus and the surrounding gyri.

RESULTS: The retrosigmoid approach allowed for clear visualization of the basal occipitotemporal surface. The collateral sulcus was identified and permitted easy endoscopic access to the ventricular atrium. The conical corridor thus obtained provided an average base working area of 3.9 cm2 at an average depth of 4.5 cm. The mean cortical thickness traversed to enter the ventricle was 1.4 cm. The intraventricular anatomy of the ipsilateral ventricle was defined clearly in all 8 exposures in this manner. The anatomy of the basal occipitotemporal surface, observed in a total of 18 hemispheres, showed a consistent pattern, with the collateral sulcus abutted by the parahippocampal gyrus medially, and the fusiform and lingual gyrus laterally. The collateral sulcus was found to be caudally bifurcated in 14 of the 18 specimens.

CONCLUSIONS: The retrosigmoid supracerebellar transtentorial transcollateral sulcus approach is technically feasible. This approach has the potential advantage of providing a short and direct path to the atrium, hence avoiding violation of deep neurovascular structures and preserving eloquent areas. Although this approach appears unconventional, it may provide a minimally invasive option for the surgical management of selected lesions within the atrium of the lateral ventricle.

 

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Volume-Staged Stereotactic Radiosurgery for Intracranial Arteriovenous Malformations

Neurosurgery 80:543–550, 2017

Radiation-based treatment options of large intracranial arteriovenous malformations (AVM) must balance the likelihood of obliteration with the risk of adverse radiation effects (ARE).
OBJECTIVE: To analyze the efficacy and risks of volume-staged stereotactic radiosurgery (VS-SRS) for AVM.

METHODS: Retrospective study of 34 AVM patients having VS-SRS between 1997 and 2012. A median of 2 stages (range, 2-4) was used to treat a median AVM volume of 22.2 cm3 (range, 7.4-56.7). The median AVM margin dose was 16 Gy (range, 14-18); the median radiosurgery- based AVM score was 2.81 (range, 1.54-6.45). The median follow-up after VS-SRS was 8.2 years (range, 3-13.3).

RESULTS: Nidus obliteration was noted in 18 patients (53%) after VS-SRS. The rate of obliteration was 14% at 3 years, 54% at 5 years, and 75% at 7 years. Six patients (18%) had 11 bleeds after VS-SRS. Two patients (6%) remained neurologically stable, 2 (6%) patients had significant deficits, and 2 patients (6%) died. The actuarial risk of a first bleed after VS-SRS was 6% at 1 year, 12% at 3 years, and 19% at 7 years. Six patients (18%) underwent repeat SRS; all achieved nidus obliteration for an overall cure rate of 71%. Two patients (6%) had a permanent ARE after VS-SRS or repeat SRS.

CONCLUSION: VS-SRS permitted large volume intracranial AVM to be treated with a low rate of ARE. Further study is needed on dose escalation and decreasing the treatment volume per stage to determine if this will increase the rate of obliteration with this technique.

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Surgery for meningioma in the elderly and long-term survival

J Neurosurg 126:1201–1211, 2017

The purpose of this study was to compare long-term prognosis after meningioma surgery in elderly and younger patients as well as to compare survival of elderly patients with surgically treated meningioma to survival rates for the general population.

METHODS Five hundred meningioma patients (median follow-up 90 months) who underwent surgery between 1994 and 2009 were subdivided into “elderly” (age ≥ 65 years, n = 162) and “younger” (age < 65 years, n = 338) groups for uni- and multivariate analyses. Mortality was compared with rates for the age- and sex-matched general population.

RESULTS The median age at diagnosis was 71 in the elderly group and 51 years in the younger group. Sex, intracranial tumor location, grade of resection, radiotherapy, and histopathological subtypes were similar in the 2 groups. Highgrade (WHO Grades II and III) and spinal tumors were more common in older patients than in younger patients (15% vs 8%, p = 0.017, and 12% vs 4%, p = 0.001, respectively). The progression-free interval (PFI) was similar in the 2 groups, whereas mortality at 3 months after surgery was higher and median overall survival (OS) was shorter in older patients (7%, 191 months) than in younger patients (1%, median not reached; HR 4.9, 95% CI 2.75–8.74; p < 0.001). Otherwise, the median OS in elderly patients did not differ from the anticipated general life expectancy (HR 1.03, 95% CI 0.70–1.50; p = 0.886). Within the older patient group, PFI was lower in patients with high-grade meningiomas (HR 24.74, 95% CI 4.23–144.66; p < 0.001) and after subtotal resection (HR 10.57, 95% CI 2.23–50.05; p = 0.003). Although extent of resection was independent of perioperative mortality, the median OS was longer after gross-total resection than after subtotal resection (HR 2.7, 95% CI 1.09–6.69; p = 0.032).

CONCLUSIONS Elderly patients with surgically treated meningioma do not suffer from impaired survival compared with the age-matched general population, and their PFI is similar to that of younger meningioma patients. These data help mitigate fears concerning surgical treatment of elderly patients in an aging society.

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Three-Dimensional Printed Modeling of Diffuse Low-Grade Gliomas and Associated White Matter Tract Anatomy

Neurosurgery 80:635–645, 2017

Diffuse low-grade gliomas (DLGGs) represent several pathological entities that infiltrate and invade cortical and subcortical structures in the brain.

OBJECTIVE: To describe methods for rapid prototyping of DLGGs and surgically relevant anatomy.

METHODS: Using high-definition imaging data and rapid prototyping technologies, we were able to generate 3 patient DLGGs to scale and represent the associated whitematter tracts in 3 dimensions using advanced diffusion tensor imaging techniques.

RESULTS: This report represents a novel application of 3-dimensional (3-D) printing in neurosurgery and a means to model individualized tumors in 3-D space with respect to subcorticalwhite matter tract anatomy. Faculty and resident evaluations of this technology were favorable at our institution.

CONCLUSION: Developing an understanding of the anatomic relationships existing within individuals is fundamental to successful neurosurgical therapy. Imaging-based rapid prototyping may improve on our ability to plan for and treat complex neuro-oncologic pathology.

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Microvascular decompression for tinnitus

J Neurosurg 126:1148–1157, 2017

The objective of this study was to examine operative outcomes in cases of microvascular decompression (MVD) of cranial nerve (CN) VIII for tinnitus through a critical review of the literature.

METHODS Forty-three English-language articles were gathered from PubMed and analyzed. In this review, two different case types were distinguished: 1) tinnitus-only symptomatology, which was defined as a patient with tinnitus with or without sensorineural hearing loss; and 2) mixed symptomatology, which was defined as tinnitus with symptoms of other CN dysfunction. This review reports outcomes of those with tinnitus-only symptoms.

RESULTS Forty-three tinnitus-only cases were found in the literature with a 60% positive outcome rate following MVD. Analysis revealed a 5-year cutoff of preoperative symptom duration before which a good outcome can be predicted with 78.6% sensitivity, and after which a poor outcome can be predicted with 80% specificity.

CONCLUSIONS As the 60% success rate is more promising than several other therapeutic options open to the chronic tinnitus sufferer, future research into this field is warranted.

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Microsurgery for cerebral arteriovenous malformations: subgroup outcomes in a consecutive series of 288 cases

J Neurosurg 126:1056–1063, 2017

The objective of this study was to review the outcomes after microsurgical resection of cerebral arteriovenous malformations (AVMs) from a consecutive single-surgeon series. Clinical and imaging data were analyzed to address the following questions concerning AVM treatment in the post-ARUBA (A Randomized Trial of Unruptured Brain Arteriovenous Malformations) era. 1) Are the patients who present with unruptured or ruptured AVMs doing better at long-term follow-up? 2) Is the differentiation between Ponce Class A (Spetzler-Martin Grade I and II) patients versus Ponce Class B and C patients (Spetzler-Martin Grade III and IV) meaningful and applicable to surgical practice? 3) How did the ARUBA-eligible patients of this surgical series compare with the results reported in ARUBA?

METHODS Two hundred eighty-eight patients with cerebral AVMs underwent microsurgical resection between 1983 and 2012 performed by the same surgeon (J.S.). This is a prospective case collection study that represents a consecutive series. The results are based on prospectively collected, early-outcome data that were supplemented by retrospectively collected, follow-up data for 94% of those cases. The analyzed data included the initial presentation, Spetzler-Martin grade, obliteration rates, surgical and neurological complications, and frequency of pretreatment with embolization or radiosurgery. The total cohort was compared using “small-AVM,” Spetzler-Martin Grade I and II, and ARUBA-eligible AVM subgroups.

RESULTS The initial presentation was hemorrhage in 50.0% and seizures in 43.1% of patients. The series included 53 Spetzler-Martin Grade I (18.4%), 114 Spetzler-Martin Grade II (39.6%), 90 Spetzler-Martin Grade III (31.3%), 28 Spetzler- Martin Grade IV (9.7%), and 3 Spetzler-Martin Grade V (1.0%) AVMs. There were 144 unruptured and 104 ARUBAeligible cases. Preembolization was used in 39 cases (13.5%). The occlusion rates for the total series and small AVM subgroup were 99% and 98.7%, respectively. The mean follow-up duration was 64 months. Early neurological deterioration was seen in 39.2% of patients, of which 12.2% had permanent and 5.6% had permanent significant deficits, and the mortality rate was 1.7% (n = 5). Outcome was better for patients with AVMs smaller than 3 cm (permanent deficit in 7.8% and permanent significant deficit in 3.2% of patients) and Ponce Class A status (permanent deficit in 7.8% and significant deficit in 3.2% of patients). Unruptured AVMs showed slightly higher new deficit rates (but 0 instances of mortality) among all cases, and in the small AVM and Ponce Class A subgroups. Unruptured Spetzler-Martin Grade I and II lesions had the best outcome (1.8% permanent significant deficit), and ARUBA-eligible Spetzler-Martin Grade I and II lesions had a slightly higher rate of permanent significant deficits (3.2%).

CONCLUSIONS Microsurgery has a very high cure rate. Focusing microsurgical AVM resection on unruptured lesions smaller than 3 cm or on Spetzler-Martin Grade I and II lesions is a good strategy for minimizing long-term morbidity. Well-selected microsurgical cases lead to better outcomes than with multimodal interventions, as in the ARUBA treatment arm, or conservative treatment alone. Long-term prospective data collection is valuable.

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Cortical plasticity catalyzed by prehabilitation enables extensive resection of brain tumors in eloquent areas

J Neurosurg 126:1323–1333, 2017

The extent of resection is the most important prognostic factor following brain glioma surgery. However, eloquent areas within tumors limit the extent of resection and, thus, critically affect outcomes. The authors hypothesized that presurgical suppression of the eloquent areas within a tumor by continuous cortical electrical stimulation, coupled with appropriate behavioral training (“prehabilitation”), would induce plastic reorganization and enable a more extensive resection.

METHODS The authors report on 5 patients harboring gliomas involving eloquent brain areas within tumors as identified on intraoperative stimulation mapping. A grid of electrodes was placed over the residual tumor, and continuous cortical electrical stimulation was targeted to the functional areas. The stimulation intensity was adjusted daily to provoke a mild functional impairment while the function was intensively trained.

RESULTS The stimulation intensity required to impair function increased progressively in all patients, and all underwent another operation a mean of 33.6 days later (range 27–37 days), when the maximal stimulation voltage in all active contacts induced no functional deficit. In all cases, a substantially more extensive resection of the tumor was possible. Intraoperative mapping and functional MRI demonstrated a plastic reorganization, and most previously demonstrated eloquent areas within the tumor were silent, while there was new functional activation of brain areas in the same region or toward the contralateral hemisphere.

CONCLUSIONS Prehabilitation with continuous cortical electrical stimulation and appropriate behavioral training prior to surgery in patients with WHO Grade II and III gliomas affecting eloquent areas accelerate plastic changes. This can help maximize tumor resection and, thus, improve survival while maintaining function.

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Intracranial pressure monitoring after primary decompressive craniectomy in traumatic brain injury

Acta Neurochir (2017) 159:615–622

Intracranial pressure (ICP) monitoring represents an important tool in the management of traumatic brain injury (TBI). Although current information exists regarding ICP monitoring in secondary decompressive craniectomy (DC), little is known after primary DC following emergency hematoma evacuation.

Methods: Retrospective analysis of prospectively collected data. Inclusion criteria were age ≥18 years and admission to the intensive care unit (ICU) for TBI and ICP monitoring after primary DC. Exclusion criteria were ICU length of stay (LOS) <1 day and pregnancy. Major objectives were: (1) to analyze changes in ICP/cerebral perfusion pressure (CPP) after primary DC, (2) to evaluate the relationship between ICP/CPP and neurological outcome and (3) to characterize and evaluate ICP-driven therapies after DC.

Results: A total of 34 patients were enrolled. Over 308 days of ICP/CPP monitoring, 130 days with at least one episode of intracranial hypertension (26 patients, 76.5%) and 57 days with at least one episode of CPP <60 mmHg (22 patients, 64.7%) were recorded. A statistically significant relationship was discovered between the Glasgow Outcome Scale (GOS) scores and mean post-decompression ICP (p < 0.04) andbetween GOS and CPP minimum (CPPmin) (p < 0.04). After DC, persisting intracranial hypertension was treated with: barbiturate coma (n = 7, 20.6%), external ventricular drain (EVD) (n = 4, 11.8%), DC diameter widening (n = 1, 2.9%) and removal of newly formed hematomas (n = 3, 8.8%).

Conclusion: Intracranial hypertension and/or low CPP occurs frequently after primary DC; their occurence is associated with an unfavorable neurological outcome. ICP monitoring appears useful in guiding therapy after primary DC.

 

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Microsurgery for cerebral arteriovenous malformations: subgroup outcomes in a consecutive series of 288 cases

J Neurosurg 126:1056–1063, 2017

The objective of this study was to review the outcomes after microsurgical resection of cerebral arteriovenous malformations (AVMs) from a consecutive single-surgeon series. Clinical and imaging data were analyzed to address the following questions concerning AVM treatment in the post-ARUBA (A Randomized Trial of Unruptured Brain Arteriovenous Malformations) era. 1) Are the patients who present with unruptured or ruptured AVMs doing better at long-term follow-up? 2) Is the differentiation between Ponce Class A (Spetzler-Martin Grade I and II) patients versus Ponce Class B and C patients (Spetzler-Martin Grade III and IV) meaningful and applicable to surgical practice? 3) How did the ARUBA-eligible patients of this surgical series compare with the results reported in ARUBA?

METHODS Two hundred eighty-eight patients with cerebral AVMs underwent microsurgical resection between 1983 and 2012 performed by the same surgeon (J.S.). This is a prospective case collection study that represents a consecutive series. The results are based on prospectively collected, early-outcome data that were supplemented by retrospectively collected, follow-up data for 94% of those cases. The analyzed data included the initial presentation, Spetzler-Mar-tin grade, obliteration rates, surgical and neurological complications, and frequency of pretreatment with embolization or radiosurgery. The total cohort was compared using “small-AVM,” Spetzler-Martin Grade I and II, and ARUBA-eligible AVM subgroups.

RESULTS The initial presentation was hemorrhage in 50.0% and seizures in 43.1% of patients. The series included 53 Spetzler-Martin Grade I (18.4%), 114 Spetzler-Martin Grade II (39.6%), 90 Spetzler-Martin Grade III (31.3%), 28 Spetzler-Martin Grade IV (9.7%), and 3 Spetzler-Martin Grade V (1.0%) AVMs. There were 144 unruptured and 104 ARUBA-eligible cases. Preembolization was used in 39 cases (13.5%). The occlusion rates for the total series and small AVM subgroup were 99% and 98.7%, respectively. The mean follow-up duration was 64 months. Early neurological deterioration was seen in 39.2% of patients, of which 12.2% had permanent and 5.6% had permanent significant deficits, and the mortality rate was 1.7% (n = 5). Outcome was better for patients with AVMs smaller than 3 cm (permanent deficit in 7.8% and permanent significant deficit in 3.2% of patients) and Ponce Class A status (permanent deficit in 7.8% and significant deficit in 3.2% of patients). Unruptured AVMs showed slightly higher new deficit rates (but 0 instances of mortality) among all cases, and in the small AVM and Ponce Class A subgroups. Unruptured Spetzler-Martin Grade I and II lesions had the best outcome (1.8% permanent significant deficit), and ARUBA-eligible Spetzler-Martin Grade I and II lesions had a slightly higher rate of permanent significant deficits (3.2%).

CONCLUSIONS Microsurgery has a very high cure rate. Focusing microsurgical AVM resection on unruptured lesions smaller than 3 cm or on Spetzler-Martin Grade I and II lesions is a good strategy for minimizing long-term morbidity. Well-selected microsurgical cases lead to better outcomes than with multimodal interventions, as in the ARUBA treatment arm, or conservative treatment alone. Long-term prospective data collection is valuable.

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The Safety and Feasibility of Image-Guided BrainPath-Mediated Transsulcul Hematoma Evacuation: A Multicenter Study

Neurosurgery 80:515–524, 2017

Subcortical injury resulting from conventional surgical management of intracranial hemorrhage may counteract the potential benefits of hematoma evacuation.

OBJECTIVE: To evaluate the safety and potential benefits of a novel, minimally invasive approach for clot evacuation in a multicenter study.

METHODS: The integrated approach incorporates 5 competencies: (1) image interpretation and trajectory planning, (2) dynamic navigation, (3) atraumatic access system (BrainPath, NICO Corp, Indianapolis, Indiana), (4) extracorporeal optics, and (5) automated atraumatic resection. Twelve neurosurgeons from 11 centers were trained to use this approach through a continuing medical education–accredited course. Demographical, clinical,andradiologicaldataofpatientstreatedover2yearswereanalyzedretrospectively.

RESULTS: Thirty-nine consecutive patients were identified. The median Glasgow Coma Scale (GCS) score at presentation was 10 (range, 5-15). The thalamus/basal ganglion regions were involved in 46% of the cases. The median hematoma volume and depth were 36 mL (interquartile range [IQR], 27-65 mL) and 1.4 cm (IQR, 0.3-2.9 cm), respectively. The median time from ictus to surgery was 24.5 hours (IQR, 16-66 hours). The degree of hematoma evacuation was ≥90%, 75% to 89%, and 50% to 74% in 72%, 23%, and 5.0% of the patients, respectively. The median GCS score at discharge was 14 (range, 8-15). The improvement in GCS score was statistically significant (P < .001). Modified Rankin Scale data were available for 35 patients. Fifty-two percent of those patients had a modified Rankin Scale score of ≤2. There were no mortalities.

CONCLUSION: The approach was safely performed in all patients with a relatively high rate of clot evacuation and functional independence.

 

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Three-Dimensional Printed Modeling of Diffuse Low-Grade Gliomas and Associated White Matter Tract Anatomy

Neurosurgery 80:635–645, 2017

Diffuse low-grade gliomas (DLGGs) represent several pathological entities that infiltrate and invade cortical and subcortical structures in the brain.

OBJECTIVE: To describe methods for rapid prototyping of DLGGs and surgically relevant anatomy.

METHODS: Using high-definition imaging data and rapid prototyping technologies, we were able to generate 3 patient DLGGs to scale and represent the associated whitematter tracts in 3 dimensions using advanced diffusion tensor imaging techniques.

RESULTS: This report represents a novel application of 3-dimensional (3-D) printing in neurosurgery and a means to model individualized tumors in 3-D space with respect to subcorticalwhite matter tract anatomy. Faculty and resident evaluations of this technology were favorable at our institution.

CONCLUSION: Developing an understanding of the anatomic relationships existing within individuals is fundamental to successful neurosurgical therapy. Imaging-based rapid prototyping may improve on our ability to plan for and treat complex neuro-oncologic pathology.

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The white matter tracts of the cerebrum in ventricular surgery and hydrocephalus

J Neurosurg 126:945–971, 2017

The relationship of the white matter tracts to the lateral ventricles is important when planning surgical approaches to the ventricles and in understanding the symptoms of hydrocephalus. The authors’ aim was to explore the relationship of the white matter tracts of the cerebrum to the lateral ventricles using fiber dissection technique and MR tractography and to discuss these findings in relation to approaches to ventricular lesions.

METHODS Forty adult human formalin-fixed cadaveric hemispheres (20 brains) and 3 whole heads were examined using fiber dissection technique. The dissections were performed from lateral to medial, medial to lateral, superior to inferior, and inferior to superior. MR tractography showing the lateral ventricles aided in the understanding of the 3D relationships of the white matter tracts with the lateral ventricles.

RESULTS The relationship between the lateral ventricles and the superior longitudinal I, II, and III, arcuate, vertical occipital, middle longitudinal, inferior longitudinal, inferior frontooccipital, uncinate, sledge runner, and lingular amygda-loidal fasciculi; and the anterior commissure fibers, optic radiations, internal capsule, corona radiata, thalamic radiations, cingulum, corpus callosum, fornix, caudate nucleus, thalamus, stria terminalis, and stria medullaris thalami were defined anatomically and radiologically. These fibers and structures have a consistent relationship to the lateral ventricles.

CONCLUSIONS Knowledge of the relationship of the white matter tracts of the cerebrum to the lateral ventricles should aid in planning more accurate surgery for lesions within the lateral ventricles.

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Volumetric growth rates of meningioma and its correlation with histological diagnosis and clinical outcome

Acta Neurochir (2017) 159:435–445

Tumour growth has been used to successfully predict progression-free survival in low-grade glioma. This systematic review sought to establish the evidence base regarding the correlation of volumetric growth rates with histological diagnosis and potential to predict clinical outcome in patients with meningioma.

Methods This systematic review was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Databases were searched for full text English articles analysing volumetric growth rates in patients with a meningioma.

Results Four retrospective cohort studies were accepted, demonstrating limited evidence of significantly different tumour doubling rates and shapes of growth curves between benign and atypical meningiomas. Heterogeneity of patient characteristics and timing of volumetric assessment, both pre- and post-operatively, limited pooled analysis of the data. No studies performed statistical analysis to demonstrate the clinical utility of growth rates in predicting clinical outcome.

Conclusion This systematic review provides limited evidence in support of the use of volumetric growth rates in meningioma to predict histological diagnosis and clinical outcome to guide future monitoring and treatment.

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Low-pressure Hydrocephalus in Children

Neurosurgery 80:439–447, 2017

Low-pressure hydrocephalus (LPH) is a rare phenomenon characterized by a clinical picture consistent with elevated intracranial pressure (ICP) and ventricular enlargement, but also a well-functioning shunt and low or negative ICP.

OBJECTIVE: To report our experience in evaluating this challenging problem. METHODS: Patients with LPH were identified from several sources, including institutional procedural databases and personal case logs. Electronic medical records were reviewed to collect demographic, clinical, surgical, and radiographic data to determine the presence of LPH. Each patient’s clinical course, including presentation, management, and outcome, is reported.

RESULTS: Thirty instances of LPH were identified in 29 patients. Eleven cases (37.9%) of LPH were after lumbar puncture (LP), and 19 cases (62.1%) occurred without any preceding spinal procedure. Among the post-LP patients, conservative measures alone were successful in 3 cases (27%); lumbar blood patch was successful in 2 cases (18%); and 6 cases (55%) required external cerebrospinal fluid (CSF) drainage. Of the spontaneous cases, 5 patients did not receive the full spectrum of treatment because of terminal prognosis. Of the remaining 14 patients, 11 (78.6%) required external CSF drainage. Post-LP patients required fewer days of external CSF drainage (median, 4 [range, 0-12] vs median, 11 [range, 0-90]) and had a shorter hospital stay (median, 2 [range, 2-16] vs median, 8 [range, 0-26]).

CONCLUSION: This study represents the largest series of LPH. Although its pathophysi-ology remains a mystery, there are a variety of management options. Multiple procedures and a protracted hospital stay are often required to successfully treat LPH.

 

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