Journal of neurosurgery
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Journal of neurosurgery · May 2018
Cyst formation after stereotactic radiosurgery for brain arteriovenous malformations: a systematic review.
OBJECTIVE Cyst formation can occasionally occur after stereotactic radiosurgery (SRS) for brain arteriovenous malformations (AVMs). Given the limited data regarding post-SRS cyst formation in patients with AVM, the time course, natural history, and management of this delayed complication are poorly defined. The aim of this systematic review was to determine the incidence, time course, and optimal management of cyst formation after SRS for AVMs. ⋯ CONCLUSIONS Cyst formation is an uncommon complication after SRS for AVMs, with a relatively long latency period. The majority of post-SRS cysts are asymptomatic and can be managed conservatively, although enlarging or symptomatic cysts may require surgical intervention. Long-term follow-up of AVM patients is crucial to the appropriate diagnosis and management of post-SRS cysts.
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Journal of neurosurgery · May 2018
Elaborate mapping of the posterior visual pathway in awake craniotomy.
OBJECTIVE Resection of intraaxial tumors adjacent to the optic radiation (OR) may be associated with postoperative visual field (VF) deficits. Intraoperative navigation using MRI-based tractography and electrophysiological monitoring of the visual pathways may allow maximal resection while preserving visual function. In this study, the authors evaluated the value of visual pathway mapping in a series of patients undergoing awake craniotomy for tumor resection. ⋯ Seven patients (38.9%) had postoperative VF deterioration, and it was associated with a length of < 8 mm between the tumor and the OR (p = 0.05). CONCLUSIONS Intraoperative electrophysiological monitoring of the visual pathways is feasible but may be of limited value in preserving the functional integrity of the posterior visual pathways. Subcortical stimulation of the OR may identify the location of the OR when done in proximity to the pathways, but such proximity may be associated with increased risk of postoperative worsening of the VF deficit.
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Journal of neurosurgery · May 2018
Gamma Knife radiosurgery for large vestibular schwannomas greater than 3 cm in diameter.
OBJECTIVE Stereotactic radiosurgery (SRS) is an important alternative management option for patients with small- and medium-sized vestibular schwannomas (VSs). Its use in the treatment of large tumors, however, is still being debated. The authors reviewed their recent experience to assess the potential role of SRS in larger-sized VSs. ⋯ No difference in outcome was observed based on indication for GKRS (p = 0.0761). CONCLUSIONS Although microsurgical resection remains the primary management choice in patients with VSs, most VSs that are defined as having both a single dimension > 3 cm and a volume > 10 cm3 and tolerable mass effect can be managed satisfactorily with GKRS. Tumor volume ≥ 15 cm3 is a significant factor predicting poor tumor control following GKRS.
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Journal of neurosurgery · May 2018
Gamma Knife surgery for clival epidural-osseous dural arteriovenous fistulas.
OBJECTIVE Clival epidural-osseous dural arteriovenous fistula (DAVF) is often associated with a large nidus, multiple arterial feeders, and complex venous drainage. In this study the authors report the outcomes of clival epidural-osseous DAVFs treated using Gamma Knife surgery (GKS). METHODS Thirteen patients with 13 clival epidural-osseous DAVFs were treated with GKS at the authors' institution between 1993 and 2015. ⋯ Two adverse events were observed following treatment, and 2 patients required repeat GKS treatment with eventual complete obliteration. CONCLUSIONS Gamma Knife surgery offers a safe and effective primary or adjuvant treatment modality for complex clival epidural-osseous DAVFs. All patients in this case series demonstrated symptomatic improvement, and almost all patients attained complete obliteration.
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OBJECTIVE Surgical approaches to the ventrolateral pons pose a significant challenge. In this report, the authors describe a safe entry zone to the brainstem located just above the trigeminal entry zone which they refer to as the "epitrigeminal entry zone." METHODS The approach is presented in the context of an illustrative case of a cavernous malformation and is compared with the other commonly described approaches to the ventrolateral pons. The anatomical nuances were analyzed in detail with the aid of surgical images and video, anatomical dissections, and high-definition fiber tractography (HDFT). ⋯ CONCLUSIONS The epitrigeminal entry zone to the brainstem appears to be safe and effective for treating intrinsic ventrolateral pontine pathological entities. A possible advantage of this approach is increased versatility in the rostrocaudal axis, providing access both above and below the trigeminal nerve. Familiarity with the subtemporal transtentorial approach, and the reliable surgical landmark of the trigeminal entry zone, should make this a straightforward approach.