Journal of neurosurgery
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Journal of neurosurgery · May 2017
CommentLow flow velocity in the middle cerebral artery predicting infarction after bypass surgery in adult moyamoya disease.
OBJECTIVE Direct and indirect bypass surgeries are recognized as the most effective treatments for preventing further stroke in adults with moyamoya disease (MMD). However, the risk factors for postoperative infarction after bypass surgery for MMD are not well established. Therefore, the objective of this study was to investigate the risk factors for postoperative infarction. ⋯ CONCLUSIONS A low MFV in the ipsilateral MCA may predict postrevascularization infarction. Bypass surgery for MMD appears to be safe in early-stage MMD. Results of TCD ultrasonography provide clinical data on the hemodynamics in MMD patients before and after revascularization.
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Journal of neurosurgery · May 2017
Microelectrode recording findings within the tractography-defined ventral intermediate nucleus.
OBJECTIVE The ventral intermediate nucleus (VIM) of the thalamus is not visible on structural MRI. Therefore, direct VIM targeting methods for stereotactic tremor surgery are desirable. The authors previously described a direct targeting method for visualizing the VIM and its structural connectivity using deterministic tractography. ⋯ Significant local field potential beta power was identified within the T-VIM (area under the curve for 13-30 Hz = 6.6 ± 7.7) with a trend toward higher beta power in the dorsal T-VIM. The most significant reduction in tremor was also observed in the dorsal T-VIM. CONCLUSIONS The electrophysiological findings within the VIM thalamus defined by tractography, or T-VIM, correspond with the known microelectrode recording characteristics of the VIM in patients with tremor.
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Journal of neurosurgery · May 2017
Nonrandom spatial clustering of spontaneous anterior fossa cerebrospinal fluid fistulas and predilection for the posterior cribriform plate.
OBJECTIVE The anterior skull base is a common site for the spontaneous development of meningoceles, encephaloceles, and meningoencephaloceles that can lead to cerebrospinal fluid (CSF) fistula formation, particularly in association with idiopathic intracranial hypertension. In some circumstances the lesions are difficult to localize. Whether all sites in the anterior skull base are equally prone to fistula formation or whether they are distributed randomly throughout the anterior skull base is unknown, although the anterior cribriform plate has been proposed as the most frequent location. ⋯ CONCLUSIONS Anterior skull base spontaneous CSF leaks are distributed in a nonrandom fashion. The most likely site of origin of the spontaneous CSF leaks of the anterior midline skull base is the cribriform plate, particularly the posterior third of the plate, likely because of the lack of significant thick bony buttressing. Clinicians searching for occult spontaneous leaks of the anterior skull base should examine the cribriform plate, especially the posterior third with particularly close scrutiny.
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Journal of neurosurgery · May 2017
CommentUltra-early angiographic vasospasm associated with delayed cerebral ischemia and infarction following aneurysmal subarachnoid hemorrhage.
OBJECTIVE The clinical significance of cerebral ultra-early angiographic vasospasm (UEAV), defined as cerebral arterial narrowing within the first 48 hours of aneurysmal subarachnoid hemorrhage (aSAH), remains poorly characterized. The authors sought to determine its frequency, predictors, and impact on functional outcome. METHODS The authors prospectively studied UEAV in a cohort of 1286 consecutively admitted patients with aSAH between August 1996 and June 2013. ⋯ Patients who exhibit UEAV are at higher risk for refractory DCI that results in cerebral infarction. These patients may benefit from earlier monitoring for signs of DCI and more aggressive treatment. Further study is needed to determine the long-term functional significance of UEAV.
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Journal of neurosurgery · May 2017
Interrater and intrarater reliability of the Knosp scale for pituitary adenoma grading.
OBJECTIVE The goal of this study was to determine the interrater and intrarater reliability of the Knosp grading scale for predicting pituitary adenoma cavernous sinus (CS) involvement. METHODS Six independent raters (3 neurosurgery residents, 2 pituitary surgeons, and 1 neuroradiologist) participated in the study. Each rater scored 50 unique pituitary MRI scans (with contrast) of biopsy-proven pituitary adenoma. ⋯ CONCLUSIONS Although these findings suggest that the Knosp grading scale has acceptable interrater reliability overall, it raises important questions about the "very weak" reliability of the scale's middle grades. By dichotomizing the scale into clinically useful groups, the authors were able to address the poor reliability and percent agreement of the intermediate grades and to isolate the most important grades for use in surgical decision making (Grades 3 and 4). Authors of future pituitary surgery studies should consider reporting Knosp grades as dichotomized results rather than as the full scale to optimize the reliability of the scale.