Journal of neurosurgery
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Journal of neurosurgery · Nov 2016
Review Case ReportsMalignant peripheral nerve sheath tumors of the eighth cranial nerve arising without prior irradiation.
OBJECTIVE Malignant peripheral nerve sheath tumors (MPNSTs) of the eighth cranial nerve (CN) are exceedingly rare. To date the literature has focused on MPNSTs occurring after radiation therapy for presumed benign vestibular schwannomas (VSs), while MPNSTs arising without prior irradiation have received little attention. The objectives of the current study are to characterize the epidemiology, clinical presentation, disease course, and outcome using a large national cancer registry database and a systematic review of the English literature. ⋯ Nearly half of patients initially present with findings consistent with a benign VS, often making an early diagnosis challenging. In light of these data, early radiological and clinical follow-up should be considered in those who elect nonoperative treatment, particularly in patients with a short duration of symptoms or atypical presentation. These data also provide a baseline rate of malignancy that should be considered when estimating the risk of malignant transformation following stereotactic radiosurgery for VS.
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Journal of neurosurgery · Nov 2016
Convection-enhanced delivery improves MRI visualization of basal ganglia for stereotactic surgery.
OBJECTIVE Stereotactic deep brain stimulation surgery is most commonly performed while patients are awake. This allows for intraoperative clinical assessment and electrophysiological target verification, thereby promoting favorable outcomes with few side effects. Intraoperative CT and MRI have challenged this concept of clinical treatment validation. ⋯ Histological analysis demonstrated mild neuronal effects from saline infusions but no effects from CSF infusions. CONCLUSIONS This work provides the initial foundation for a novel approach to improve the visualization of deep brain anatomy during MRI-guided, stereotactic procedures. Convective infusions of CSF alter the extracellular fluid content of the brain for improved MRI without evidence of clinical or toxic effects.
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Journal of neurosurgery · Nov 2016
Extension of diffuse low-grade gliomas beyond radiological borders as shown by the coregistration of histopathological and magnetic resonance imaging data.
OBJECTIVE Magnetic resonance imaging tends to underestimate the extent of diffuse low-grade gliomas (DLGGs). With the aim of studying the presence of tumor cells outside the radiological border, the authors developed a method of correlating MRI findings with histological data in patients with suspected DLGGs in whom en bloc resections were performed. METHODS Five patients with suspected DLGG suitable for en bloc resection were recruited from an ongoing prospective study. ⋯ This technique can be applied to evaluate the sensitivity of alternative imaging methods to detect scattered tumor cells at tumor borders. Accurate methods for detection of infiltrative tumor cells will improve the possibility of performing radical tumor resection. In future studies, the method could also be used for in vivo studies of tumor invasion.
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Journal of neurosurgery · Nov 2016
Intraoperative premature rupture of middle cerebral artery aneurysms: risk factors and sphenoid ridge proximation sign.
OBJECTIVE This study was an investigation of surgical cases of a ruptured middle cerebral artery (MCA) aneurysm that was conducted to identify the risk factors of an intraoperative premature rupture. METHODS Among 927 patients with a ruptured intracranial aneurysm who were treated over an 8-year period, the medical records of 182 consecutive patients with a ruptured MCA aneurysm were examined for cases of a premature rupture, and the risk factors were then investigated. The risk factors considered for an intraoperative premature rupture of an MCA aneurysm included the following: patient age; sex; World Federation of Neurosurgical Societies clinical grade; modified Fisher grade; presence of an intracerebral hemorrhage (ICH); location of the ICH (frontal or temporal); volume of the ICH; maximum diameter of the ruptured MCA aneurysm; length of the preaneurysmal M1 segment between the carotid bifurcation and the MCA aneurysm; and a sign of sphenoid ridge proximation. ⋯ Plus, a receiver operating characteristic curve analysis revealed that a preaneurysmal M1 segment length ≤ 13.3 mm was the best cutoff value for predicting the occurrence of a premature rupture (area under curve 0.747; sensitivity 63.64%; specificity 81.66%). CONCLUSIONS Patients exhibiting a sphenoid ridge proximation sign, the presence of a frontal ICH, and/or a short preaneurysmal M1 segment are at high risk for an intraoperative premature rupture of a MCA aneurysm. Such high-risk MCA aneurysms have a superficial location close to the arachnoid in the sphenoidal compartment of the sylvian fissure and have a rupture point directed anteriorly.
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Journal of neurosurgery · Nov 2016
Microsurgical management of vestibular schwannoma after failed previous surgery.
OBJECTIVE Microsurgical treatment of recurrent vestibular schwannoma (VS) is difficult and poses specific challenges. The authors report their experience with 53 cases of surgically treated recurrent VS. Outcome of these tumors was compared to that of primarily operated on VS. ⋯ Most of the patients showed improvement of the preoperative symptoms, such as trigeminal hypesthesia, gait disturbance, and headache. CONCLUSIONS Complete microsurgical tumor removal is the optimal management for patients with recurrent or regrowing VS. The procedure is safe, associated with favorable facial nerve outcome, and may also improve existing neurological symptoms.