Journal of Neurosurgery

Publisher: American Association of Neurological Surgeons, American Association of Neurological Surgeons

Current impact factor: 3.74

Impact Factor Rankings

2016 Impact Factor Available summer 2017
2014 / 2015 Impact Factor 3.737
2011 Impact Factor 2.965

Additional details

5-year impact 3.57
Cited half-life >10.0
Immediacy index 0.63
Eigenfactor 0.03
Article influence 1.13
Other titles Journal of neurosurgery (Online), Journal of neurosurgery, JNS
ISSN 1933-0693
OCLC 44743688
Material type Document, Periodical, Internet resource
Document type Internet Resource, Computer File, Journal / Magazine / Newspaper

Publisher details

American Association of Neurological Surgeons

  • Pre-print
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  • Conditions
    • NIH authors may submit articles to PubMed Central 12 months after publication (publisher will supply necessary files)
    • Wellcome Trust authors may comply with their grant conditions
    • Publisher last reviewed on 24/06/2015
  • Classification
    white

Publications in this journal


  • No preview · Article · Jan 2016 · Journal of Neurosurgery

  • No preview · Article · Jan 2016 · Journal of Neurosurgery
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    ABSTRACT: OBJECTIVE The goal of this study was to demonstrate that repetitive pure oxygen exposure preconditioning (O2PC) for 8 hours per day for 3 or 7 days, a practicable preconditioning for clinical use, is able to induce cerebral ischemic tolerance (IT) and further clarify the accompanying changes in the blood-brain barrier (BBB) that may be involved. METHODS A total of 68 adult male Sprague-Dawley rats and eight 1-day-old rat pups were used in this study. The adult rats were exposed to pure O2 (38 rats) 8 hours a day for 3 or 7 days or to room air (in an identical setup) for 8 hours a day for 7 days as controls (30 rats). Arterial O2 tension (PaO2) was measured in 6 rats exposed to O2 and 3 controls. Focal cerebral ischemia was elicited by middle cerebral artery occlusion (MCAO) in 37 rats, of which 21 had been exposed to pure O2 for 3 or 7 days and 16 to room air for 7 days as controls. Neurological behavior was scored with the Garcia score in 15 MCAO rats, of which 10 had been exposed to pure O2 for 3 or 7 days and 5 to room air for 7 days as controls, and cerebral infarct volumes were assessed with TTC (2,3,5-triphenyltetrazolium chloride) staining in 10 rats (5 from each group) after 7 days of exposure. Formamide-extraction method was used to detect leakage of Evans blue (EB) dye in 7 rats exposed to pure O2 for 7 days and 7 exposed to room air for 7 days. Fluorescence microscopy was used to analyze the leaked EB in the nonischemic areas of 4 rats exposed to pure O2 for 7 days and 4 exposed to room air for 7 days before MCAO and the brain of the rats that had not been subjected to MCAO. Astrocyte changes associated with O2PC were evaluated by means of fluorescence microscopy and electron microscopy in 14 rats that were exposed to the same O2 or control conditions as the MCAO rats but without MCAO. Astrocytes were also obtained from 8 rat pups and cultured; levels of AQP4 and VEGF were detected by Western blot and ELISA in cells with and without O2 treatment. RESULTS A significant increase in PaO2 was seen after O2PC. The neurological score was significantly increased in the O2PC groups (10.6 ± 0.6 in the 3-day O2PC group, p < 0.05; 12 ± 0.84 in the 7-day O2PC group, p < 0.05) compared with the control group (7 ± 0.55). The ratio of cerebral infarct volume to contralateral cerebral hemisphere volume was significantly lower in the O2PC group than in the control group (0.204 ± 0.03 vs 0.48 ± 0.05, p < 0.05). The amount of leaked EB in the ischemic cerebral hemisphere was also lower in the O2-treated rats than in controls (7.53 ± 1.4 vs 11.79 ± 3.3 μg EB/g brain weight, p < 0.05). However, fluorescence microscopy showed significantly greater BBB permeability in the nonischemic areas in the O2PC group than in controls (p < 0.05). More red fluorescence could be observed in the nonischemic areas in both the ipsilateral and contralateral sides of the ischemic brain in the O2PC animals than in the nonischemic areas in the corresponding sides of the controls. Further investigation of the effect of the O2PC itself on the BBB of rats that were not subjected to MCAO showed that there was no EB leakage in the brain parenchyma in the rats exposed to room air, but some red fluorescence patches were noticed in the normal brain from the rats in the O2PC group. Astrocytes, including those from areas around the BBB, were activated in the O2PC group. Levels of both aquaporin 4 (AQP4) and vascular endothelial growth factor (VEGF) were significantly increased in cultured astrocytes after O2PC. CONCLUSIONS These findings suggest that O2PC is able to induce IT, which makes it a strong candidate for clinical use. Moreover, O2PC can also promote BBB opening, which may contribute to the induction of IT as well as representing a possible strategy for promoting drug transportation into the CNS. Activated astrocytes are likely to be involved in these processes through astrocyte-derived factors, such as AQP4 and VEGF.
    No preview · Article · Jan 2016 · Journal of Neurosurgery
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    ABSTRACT: OBJECTIVE Many colloid cyst patients present with obstructive hydrocephalus that resolves after resection of the cyst. However, a proportion of patients with these cysts will require cerebrospinal fluid shunting after tumor resection, despite resolution of the obstruction at the foramina of Monro. The goal of this study was to determine if colloid cyst size or preoperative ventricular volume predicted the need for postresection shunting. METHODS In a retrospective study design, ICD-9 codes 742.2 (colloid cyst) and 348.0 (brain cyst) were used to identify patients who had undergone resection of a colloid cyst at the University of Florida over the last 20 years. Preoperative imaging (CT or MRI) with a stereotactic software program developed at the University of Florida was used to measure volumes of the colloid cyst and the lateral ventricles. The relationships among ventricular volume, colloid cyst volume, and postoperative shunting were analyzed. RESULTS The number of patients included in the study was 67, and their mean age was 37.7 years. Forty percent of the patients were female. Overall, 49.2% of the patients had a transcallosal approach, 35.8% a transcortical approach, and 14.9% an endoscope-assisted surgery. Mean preoperative ventricular volume was 76.5 cc in patients who never received a ventriculoperitoneal shunt (VPS) and 98.1 cc in those who were eventually treated with a VPS (p = 0.305). Patients with a postoperative VPS had an initial mean colloid cyst volume of 1.8 cc compared with 0.9 cc in patients without a VPS postoperatively (p = 0.019). Patients with colloid cysts larger than 0.6 cc (1-cm diameter) had a 12.8 increased odds of needing a VPS postoperatively (95% CI 1.81-275). CONCLUSIONS Larger colloid cysts are associated with an increased need for postresection shunting independent of preoperative ventricular size. Prospective studies of patients with colloid cysts are necessary to further identify risks of permanent hydrocephalus.
    No preview · Article · Jan 2016 · Journal of Neurosurgery
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    ABSTRACT: OBJECTIVE Dissection of the carotid and vertebral arteries can result in the development of aneurysmal dilations. These dissecting pseudoaneurysms can enlarge and cause symptoms. The objective of this study is to provide insight into the progression of dissecting pseudoaneurysms and the treatments required to manage them. METHODS A review of the electronic medical records was conducted to detect patients with carotid and vertebral artery dissection. An imaging review was conducted to identify patients with dissecting pseudoaneurysms. One hundred twelve patients with 120 dissecting pseudoaneurysms were identified. Univariate and multivariate analyses were conducted to assess the factors associated with undergoing further interventions other than medical treatment, pseudoaneurysm enlargement, pseudoaneurysms resulting in ischemic and nonischemic symptoms, and clinical outcome. RESULTS Overall, 18.3% of pseudoaneurysms were intracranial and 81.7% were extracranial, and the average size was 7.3 mm. The mean follow-up time was 29.3 months; 3.3% of patients had a recurrent transient ischemic attack, no patients had a recurrent stroke, and 14.2% of patients had recurrence of nonischemic symptoms (headache, neck pain, Horner syndrome, or cranial nerve palsy). Follow-up imaging demonstrated that 13.8% of pseudoaneurysms had enlarged, 30.2% had healed, and 56% had remained stable. In total, 20.8% of patients had an intervention other than medical treatment. Interventions included stenting, coiling, flow diversion, and clipping. Predictors of intervention included increasing size, size > 10 mm, location in the C2 (petrous) segment of the internal carotid artery (ICA), younger age, hyperlipidemia, pseudoaneurysm enlargement, and any symptom development. Significant predictors of enlargement included smoking, history of trauma, C2 location, hyperlipidemia, and larger initial pseudoaneurysm size. Predictors of pseudoaneurysm resulting in recurrent ischemic and nonischemic symptoms included increasing size and location in the petrous segment of the ICA. Smoking was a predictor of unfavorable outcome. CONCLUSIONS Dissecting pseudoaneurysms have a benign course and most will not cause symptoms or enlarge on follow-up. Medical treatment can be a sufficient, initial treatment for dissecting pseudoaneurysms.
    No preview · Article · Jan 2016 · Journal of Neurosurgery
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    ABSTRACT: OBJECTIVE This study investigated whether the increased incidence of aneurysmal subarachnoid hemorrhage (SAH) in winter is related to temperature or increased incidence of influenza. Such relationships may elucidate the pathogenesis of intracranial aneurysm rupture. METHODS A nationwide sample of 18,714 patients with SAH was linked with weekly temperature and influenza-like illness consultation data. Poisson regression analyses were used to calculate incidence density ratios (IDRs) with corresponding 95% CIs for the association of SAH incidence with temperature and influenza epidemics; IDRs were adjusted for study year (aIDR). In addition, SAH incidence data from 30 European population-based studies were linked with daily temperature data from the European Climate Assessment. RESULTS The aIDR for SAH during influenza epidemics was 1.061 (95% CI 1.022-1.101) in the univariable and 1.030 (95% CI 0.989-1.074) in the multivariable analysis. This association declined gradually during the weeks after epidemics. Per 1°C temperature drop, the aIDR was 1.005 (95% CI 1.003-1.008) in the univariable and 1.004 (95% CI 1.002-1.007) in the multivariable analysis. In the European population-based studies, the IDR was 1.143 (95% CI 1.129-1.157) per 1°C temperature drop. CONCLUSIONS The incidence of SAH is increased during cold temperatures and epidemic influenza. Future studies with individual patient data are needed to investigate causality between temperature or influenza and SAH.
    No preview · Article · Jan 2016 · Journal of Neurosurgery
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    ABSTRACT: OBJECTIVE Arterial spin labeling perfusion-weighted imaging (ASL-PWI) enables quantification of tissue perfusion without contrast media administration. The aim of this study was to explore whether cerebral blood flow (CBF) from ASL-PWI can reliably predict angiographic vascularity of meningiomas. METHODS Twenty-seven patients with intracranial meningiomas, who had undergone preoperative ASL-PWI and digital subtraction angiography prior to resection, were included. Angiographic vascularity was assessed using a 4-point grading scale and meningiomas were classified into 2 groups: low vascularity (Grades 0 and 1; n = 11) and high vascularity (Grades 2 and 3; n = 16). Absolute CBF, measured at the largest section of the tumor, was normalized to the contralateral gray matter. Correlation between the mean normalized CBF (nCBF) and angiographic vascularity was determined and the mean nCBF values of the 2 groups were compared. Diagnostic performance of the nCBF for differentiating between the 2 groups was assessed. RESULTS The nCBF had a significant positive correlation with angiographic vascularity (ρ = 0.718; p < 0.001). The high-vascularity group had a significantly higher nCBF than the low-vascularity group (3.334 ± 2.768 and 0.909 ± 0.468, respectively; p = 0.003). At the optimal nCBF cutoff value of 1.733, sensitivity and specificity for the differential diagnosis of the 2 groups were 69% (95% CI 41%-89%) and 100% (95% CI 72%-100%), respectively. The area under the receiver operating characteristic curve was 0.875 (p < 0.001). CONCLUSIONS ASL-PWI may provide a reliable and noninvasive means of predicting angiographic vascularity of meningiomas. It may thus assist in selecting potential candidates for preoperative digital subtraction angiography and embolization in clinical practice.
    No preview · Article · Jan 2016 · Journal of Neurosurgery
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    ABSTRACT: OBJECTIVE Of the intracranial schwannomas, those arising from the vestibular nerves are the most common. Abducens nerve (AN) schwannomas are very rare, and there is limited literature on their optimal management. Therapeutic options include surgery and/or stereotactic radiosurgery. The aim of this study was to evaluate the role of Gamma Knife radiosurgery (GKRS) in these sixth cranial nerve (CN) schwannomas. METHODS The authors performed a retrospective analysis of patients who had undergone GKRS for intracranial tumors at their institute in the period from 2003 to 2010. Inclusion criteria were as follows: isolated AN paresis on presentation, a lesion along the course of the sixth CN, and imaging features characteristic of a schwannoma. Patients with other CN deficits and neurofibromatosis Type 2 were excluded. Symptomatic improvement was defined as the resolution of or an improvement in diplopia noted on a subjective basis or as an improvement in lateral eyeball excursion noted objectively on follow-up. A reduction in tumor volume by at least 20%, as noted by comparing the pre- and post-GKRS images, was deemed significant. RESULTS Six patients with a mean age of 37.1 years (range 17-55 years) underwent primary GKRS. There were 2 prepontine cistern, 3 cavernous sinus, and 1 cisterno-cavernous tumor. The mean duration of symptoms was 6.1 months (range 3-12 months). The mean tumor volume was 3.3 cm(3) (range 1.5-4.8 cm(3)). The mean tumor margin radiation dose was 12.5 Gy (range 12-14 Gy), while the median margin dose was 12 Gy (50% isodose line). The median number of isocenters used was 5 (range 4-8). The brainstem received an average 8.35-Gy radiation dosage (range 5.5-11 Gy). The mean follow-up duration was 44.3 months (range 24-78 months). Symptoms remained stable in 1 patient, improved in 3, and resolved in 2 (total improvement 83%). Magnetic resonance imaging at the last follow-up showed a stable tumor size in 3 patients (50%) and a reduction in the other 3. Thus, the tumor control rate achieved was 100%. No new CN deficits were noted. CONCLUSIONS Abducens nerve schwannomas are rare intracranial tumors. They can be cavernous, cisternal, or cisterno-cavernous in location. Excellent tumor control rates and symptomatic improvement can be achieved with GKRS, which appears to be a safe and effective, minimally invasive modality for the treatment of such lesions. Therefore, it is reasonable to consider GKRS as the initial treatment of choice for this rare pathology. Long-term follow-up will be essential for further recommendations.
    No preview · Article · Jan 2016 · Journal of Neurosurgery
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    ABSTRACT: OBJECTIVE The object of this study was to examine the relationships of the cochlea as a guide for avoiding both cochlear damage with loss of hearing in middle fossa approaches and injury to adjacent structures in approaches directed through the cochlea. METHODS Twenty adult cadaveric middle fossae were examined using magnifications of ×3 to ×40. RESULTS The cochlea sits below the floor of the middle fossa in the area between and below the labyrinthine segment of the facial nerve and greater petrosal nerve (GPN) and adjacent to the lateral genu of the petrous carotid. Approximately one-third of the cochlea extends below the medial edge of the labyrinthine segment of the facial nerve, geniculate ganglion, and proximal part of the GPN. The medial part of the basal and middle turns are the parts at greatest risk in drilling the floor of the middle fossa to expose the nerves in middle fossa approaches to the internal acoustic meatus and in anterior petrosectomy approaches. Resection of the cochlea is used selectively in extending approaches through the mastoid toward the lateral edge of the clivus and front of the brainstem. CONCLUSIONS An understanding of the location and relationships of the cochlea will reduce the likelihood of cochlear damage with hearing loss in approaches directed through the middle fossa and reduce the incidence of injury to adjacent structures in approaches directed through the cochlea.
    No preview · Article · Jan 2016 · Journal of Neurosurgery
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    ABSTRACT: OBJECTIVE Recent advances in radiotherapy and neuroimaging have called into question the traditional role of aggressive resections in patients with meningiomas. In the present study the authors reviewed their institutional experience with a policy based on maximal safe resections for meningiomas, and they analyzed the impact of the degree of resection on functional outcome and progression-free survival (PFS). METHODS The authors retrospectively analyzed 901 consecutive patients with primary meningiomas (716 WHO Grade I, 174 Grade II, and 11 Grade III) who underwent resections at the University Hospital of Bonn between 1996 and 2008. Clinical and treatment parameters as well as tumor characteristics were analyzed using standard statistical methods. RESULTS The median follow-up was 62 months. PFS rates at 5 and 10 years were 92.6% and 86.0%, respectively. Younger age, higher preoperative Karnofsky Performance Scale (KPS) score, and convexity tumor location, but not the degree of resection, were identified as independent predictors of a good functional outcome (defined as KPS Score 90-100). Independent predictors of PFS were degree of resection (Simpson Grade I vs II vs III vs IV), MIB-1 index (< 5% vs 5%-10% vs >10%), histological grade (WHO I vs II vs III), tumor size (≤ 6 vs > 6 cm), tumor multiplicity, and location. A Simpson Grade II rather than Grade I resection more than doubled the risk of recurrence at 10 years in the overall series (18.8% vs 8.5%). The impact of aggressive resections was much stronger in higher grade meningiomas. CONCLUSIONS A policy of maximal safe resections for meningiomas prolongs PFS and is not associated with increased morbidity.
    No preview · Article · Jan 2016 · Journal of Neurosurgery
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    ABSTRACT: OBJECTIVE The aim of this study was to define a new protocol for intraoperative monitoring (IOM) of brainstem auditory evoked potentials (BAEPs) during microvascular decompression (MVD) surgery to treat hemifacial spasm (HFS) and to evaluate the usefulness of this new protocol to prevent hearing impairment. METHODS To define the optimal stimulation rate, estimate the number of trials to be averaged, and identify useful warning criteria in IOM of BAEPs, the authors performed a preliminary study of 13 patients with HFS in 2010. They increased the stimulation rate from 10.1 Hz/sec to 100.1 Hz/sec by 10-Hz increments, and they elevated the average time from 100 times to 1000 times by 100-unit increments at a fixed stimulus rate of 43.9 Hz. After defining the optimal stimulation rate and the number of trials that needed to be averaged for IOM of BAEPs, they also identified the useful warning criteria for this protocol for MVD surgery. From January to December 2013, 254 patients with HFS underwent MVD surgery following the new IOM of BAEPs protocol. Pure-tone audiometry and speech discrimination scoring were performed before surgery and 1 week after surgery. To evaluate the usefulness of the new protocol, the authors compared the incidence of postoperative hearing impairment with the results from the group that underwent MVD surgery prior to the new protocol. RESULTS Through a preliminary study, the authors confirmed that it was possible to obtain a reliable wave when using a stimulation rate of 43.9 Hz/sec and averaging 400 trials. Only a Wave V amplitude loss > 50% was useful as a warning criterion when using the new protocol. A reliable BAEP could be obtained in approximately 9.1 seconds. When the new protocol was used, 2 patients (0.8%) showed no recovery of Wave V amplitude loss > 50%, and only 1 of those 2 patients (0.39%) ultimately had postoperative hearing impairment. When compared with the outcomes in the pre-protocol group, hearing impairment incidence decreased significantly among patients who underwent surgery with the new protocol (0.39% vs 4.02%, p = 0.002). There were no significant differences between the 2 surgery groups regarding other complications, including facial palsy, sixth cranial nerve palsy, and vocal cord palsy. CONCLUSIONS There was a significant decrease in postoperative hearing impairment after MVD for HFS when the new protocol for IOM of BAEPs was used. Real-time IOM of BAEPs, which can obtain a reliable BAEP in less than 10 seconds, is a successful new procedure for preventing hearing impairment during MVD surgery for HFS.
    No preview · Article · Jan 2016 · Journal of Neurosurgery

  • No preview · Article · Jan 2016 · Journal of Neurosurgery
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    ABSTRACT: OBJECTIVE Reimplantation of the posterior inferior cerebellar artery (PICA) to the vertebral artery (VA) is a safe and effective bypass option after deliberate PICA sacrifice during the treatment of nonsaccular and dissecting aneurysms at this location. However, the anatomy and limitations of this technique have not been studied. The goal of this study was to define the surgical anatomy and buffer lengths specific to the proximal segment of the PICA related to 2 variations of PICA reimplantation: 1) reimplantation "along-VA" (simulating a dissecting VA aneurysm), and 2) reimplantation "across-VA" (simulating a nonclippable, proximal PICA aneurysm). METHODS Ten cadaver heads (20 sides) were prepared for surgical simulation. Twenty far-lateral approaches were performed. The PICA was mobilized and reimplanted onto the VA according to 2 different paradigms: 1) transposition along the axis of the VA (along-VA) to simulate a dissecting VA, and 2) transposition perpendicular to the axis of the VA (across-VA) to simulate a nonclippable, proximal PICA aneurysm. The buffer lengths provided by mobilization of the artery in each paradigm were measured and the anatomy of perforator branching on the proximal PICAs was analyzed. RESULTS The PICA was reimplanted in all surgical simulations. The most common perforating artery on the P1 and P2 segments was the short circumflex type. No direct perforator was found on the P1 segment. The mean buffer length with reimplantation along the VA axis was 13.43 ± 4.61 mm, and it was 6.97 ± 4.04 mm with reimplantation across the VA. The PICA was less maneuverable when it was reimplanted across the VA, due to perforator branches of the PICA (P3 segment). CONCLUSIONS The buffer lengths measured in this study describe the limitations of PICA reimplantation as a revascularization procedure for nonsaccular aneurysms in this location. PICA reimplantation is a revascularization option for dissecting VA aneurysms incorporating the PICA origin that are < 13 mm in length, and for nonsaccular proximal PICA aneurysms that are < 6 mm in diameter. The final decision to reimplant the PICA depends on careful inspection of perforator anatomy that is not visible preoperatively on angiography, as well as an assessment of technical difficulty intraoperatively.
    No preview · Article · Jan 2016 · Journal of Neurosurgery
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    ABSTRACT: The historical origin of the meningioma nomenclature unravels interesting social and political aspects about the development of neurosurgery in the late 19th century. The meningioma terminology itself was the subject of nationalistic pride and coincided with the advancement in the rise of medicine in Continental Europe as a professional social enterprise. Progress in naming and understanding these types of tumor was most evident in the nations that successively assumed global leadership in medicine and biomedical science throughout the 19th and 20th centuries, that is, France, Germany, and the United States. In this vignette, the authors delineate the uniqueness of the term "meningioma" as it developed within the historical framework of Continental European concepts of tumor genesis, disease states, and neurosurgery as an emerging discipline culminating in Cushing's Meningiomas text. During the intellectual apogee of the French Enlightenment, Antoine Louis published the first known scientific treatise on meningiomas. Like his father, Jean-Baptiste Louis, Antoine Louis was a renowned military surgeon whose accomplishments were honored with an admission to the Académie royale de chirurgie in 1749. His treatise, Sur les tumeurs fongueuses de la duremère, appeared in 1774. Following this era, growing economic depression affecting a frustrated bourgeoisie triggered a tumultuous revolutionary period that destroyed France's Ancien Régime and abolished its university and medical systems. The resulting anarchy was eventually quelled through legislation aiming to satisfy Napoleon's need for qualified military professionals, including physicians and surgeons. These laws laid the foundations for the subsequent flourishing of French medicine throughout the mid-19th century. Subsequent changes to the meningioma nomenclature were authored by intellectual giants of this postrevolutionary period, for example, by the Limogesborn pathologist Jean Cruveilhier known for the term "tumeurs cancéreuses de la duremère," and the work of histopathologists, such as Hermann Lebert, who were influenced by Pasteur's germ theory and by Bernard's experimental medicine. The final development of the meningioma nomenclature corresponded to the rise of American neurosurgery as a formal academic discipline. This historical period of growth is chronicled in Cushing's text Meningiomas, and it set the scientific stage for the modern developments in meningioma research and surgery that are conducted and employed today.
    No preview · Article · Jan 2016 · Journal of Neurosurgery
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    ABSTRACT: OBJECTIVE Identification of language areas using functional brain mapping is sometimes impossible using current methods but essential to preserve language function in patients with gliomas located within or near the frontal language area (FLA). However, the factors that influence the failure to detect language areas have not been elucidated. The present study evaluated the difficulty in identifying the FLA in dominant-side frontal gliomas that involve the pars triangularis (PT) to determine the factors that influenced failed positive language mapping. METHODS Awake craniotomy was performed on 301 patients from April 2000 to October 2013 at Tokyo Women's Medical University. Recurrent cases were excluded, and patients were also excluded if motor mapping indicated their glioma was in or around the motor area on the dominant or nondominant side. Eighty-two consecutive cases of primary frontal glioma on the dominant side were analyzed for the present study. MRI was used for all patients to evaluate whether tumors involved the PT and to perform language functional mapping with a bipolar electrical stimulator. Eighteen of 82 patients (mean age 39 ± 13 years) had tumors that showed involvement of the PT, and the detailed characteristics of these 18 patients were examined. RESULTS The FLA could not be identified with intraoperative brain mapping in 14 (17%) of 82 patients; 11 (79%) of these 14 patients had a tumor involving the PT. The negative response rate in language mapping was only 5% in patients without involvement of the PT, whereas this rate was 61% in patients with involvement of the PT. Univariate analyses showed no significant correlation between identification of the FLA and sex, age, histology, or WHO grade. However, failure to identify the FLA was significantly correlated with involvement of the PT (p < 0.0001). Similarly, multivariate analyses with the logistic regression model showed that only involvement of the PT was significantly correlated with failure to identify the FLA (p < 0.0001). In 18 patients whose tumors involved the PT, only 1 patient had mild preoperative dysphasia. One week after surgery, language function worsened in 4 (22%) of 18 patients. Six months after surgery, 1 (5.6%) of 18 patients had a persistent mild speech deficit. The mean extent of resection was 90% ± 7.1%. Conclusions Identification of the FLA can be difficult in patients with frontal gliomas on the dominant side that involve the PT, but the positive mapping rate of the FLA was 95% in patients without involvement of the PT. These findings are useful for establishing a positive mapping strategy for patients undergoing awake craniotomy for the treatment of frontal gliomas on the dominant side. Thoroughly positive language mapping with subcortical electrical stimulation should be performed in patients without involvement of the PT. More careful continuous neurological monitoring combined with subcortical electrical stimulation is needed when removing dominant-side frontal gliomas that involve the PT.
    No preview · Article · Jan 2016 · Journal of Neurosurgery
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    ABSTRACT: OBJECTIVE Warning criteria for monitoring of motor evoked potentials (MEP) after direct cortical stimulation during surgery for supratentorial tumors have been well described. However, little is known about the value of MEP after transcranial electrical stimulation (TES) in predicting postoperative motor deficit when monitoring threshold level. The authors aimed to evaluate the feasibility and value of this method in glioma surgery by using a new approach for interpreting changes in threshold level involving contra- and ipsilateral MEP. METHODS Between November 2013 and December 2014, 93 patients underwent TES-MEP monitoring during resection of gliomas located close to central motor pathways but not involving the primary motor cortex. The MEP were elicited by transcranial repetitive anodal train stimulation. Bilateral MEP were continuously evaluated to assess percentage increase of threshold level (minimum voltage needed to evoke a stable motor response from each of the muscles being monitored) from the baseline set before dural opening. An increase in threshold level on the contralateral side (facial, arm, or leg muscles contralateral to the affected hemisphere) of more than 20% beyond the percentage increase on the ipsilateral side (facial, arm, or leg muscles ipsilateral to the affected hemisphere) was considered a significant alteration. Recorded alterations were subsequently correlated with postoperative neurological deterioration and MRI findings. RESULTS TES-MEP could be elicited in all patients, including those with recurrent glioma (31 patients) and preoperative paresis (20 patients). Five of 73 patients without preoperative paresis showed a significant increase in threshold level, and all of them developed new paresis postoperatively (transient in 4 patients and permanent in 1 patient). Eight of 20 patients with preoperative paresis showed a significant increase in threshold level, and all of them developed postoperative neurological deterioration (transient in 4 patients and permanent in 4 patients). In 80 patients no significant change in threshold level was detected, and none of them showed postoperative neurological deterioration. The specificity and sensitivity in this series were estimated at 100%. Postoperative MRI revealed gross-total tumor resection in 56 of 82 patients (68%) in whom complete tumor resection was attainable; territorial ischemia was detected in 4 patients. CONCLUSIONS The novel threshold criterion has made TES-MEP a useful method for predicting postoperative motor deficit in patients who undergo glioma surgery, and has been feasible in patients with preoperative paresis as well as in patients with recurrent glioma. Including contra- and ipsilateral changes in threshold level has led to a high sensitivity and specificity.
    No preview · Article · Jan 2016 · Journal of Neurosurgery