Finchdavis3995

71, 95% confidence interval [CI] 2.20-54.35, p =  0.005) and symptomatic bilateral leaks (OR 9.67, 95% CI 2.22-40.17, p  = 0.01. All PFD patients had arachnoid granulations adjacent to ipsilateral mastoid cell opacification. However, this finding was often subtle and rarely included on the radiology report. There was no significant difference in body mass index, age, presenting complaints, or operative success between the PFD and isolated tegmen defect sCSFL cohorts. Conclusion  The posterior fossa is an uncommon location for sCSFL. Careful review of preoperative imaging is often suggestive and can inform surgical approach. PFD patients are similar to those with isolated tegmen-based defects in presentation, comorbidities, and outcomes.Objective  Transcanal endoscopic operative approaches provide for a minimally invasive surgical portal to the lateral skull base. Traditional preoperative imaging evaluation involves computed tomography (CT) acquisition in the axial and coronal planes that are not optimized for the transcanal surgical corridor. Herein, we describe a novel CT-based "transcanal view" for preoperative surgical planning and intraoperative navigation. Study Design  Present study is a cadaveric imaging study. Methods  Cadaveric temporal bones ( n  = 6) from three specimens underwent high-resolution CT (0.625 mm slice thickness). Using three-dimensional (3D) Slicer 4.8, reformatted "transcanal" views in the plane of the external auditory canal (EAC) were created. Axial and coronal reformats were used to compare and measure distances between anatomic structures in the plane of the EAC. Results  The degree of oblique tilt for transcanal CT reformats was 6.67 ± 1.78 degrees to align the EAC in axial and coronal planes. Anticipated critical landmarks were identified easily using the transcanal view. Mean values were 8.68 ± 0.38 mm for annulus diameter, 9.5 ± 0.93 mm for isthmus diameter, 10.27 ± 0.73 mm for distance between annulus and isthmus, 2.95 ± 0.13 mm for distance between annulus and stapes capitulum, 5.12 ± 0.35 mm for distance between annulus and mastoid facial nerve, and 19.54 ± 1.22 mm for EAC length. Conclusion  This study is the first to illustrate a novel "transcanal" CT sequence intended for endoscopic lateral skull base surgery. Future studies may address how incorporation of a transcanal CT reformat may influence surgical decision making.Objective  Cystic vestibular schwannomas (CVSs) are anecdotally believed to have worse clinical and tumor-control outcomes than solid vestibular schwannomas (SVSs); however, no data have been reported to support this belief. In this study, we characterize the clinical outcomes of patients with CVSs versus those with SVSs. Design  This is a retrospective review of prospectively collected data. Setting  This study is set at single high-volume neurosurgical institute. Participants  We queried a database for details on all patients diagnosed with vestibular schwannomas between January 2009 and January 2014. Main Outcome Measures  Records were retrospectively reviewed and analyzed using univariate and multivariate analyses to study the differences in clinical outcomes and tumor progression or recurrence. Results  Of a total of 112 tumors, 24% ( n  = 27) were CVSs and 76% ( n  = 85) were SVSs. Univariate analysis identified the extent of resection, Koos grade, and tumor diameter as significant predictors of recurrence ( p  ≤ 0.005). However, tumor diameter was the only significant predictor of recurrence in the multivariate analysis ( p  = 0.007). Cystic change was not a predictor of recurrence in the univariate or multivariate analysis ( p  ≥ 0.40). Postoperative facial nerve and hearing outcomes were similar for both CVSs and SVSs ( p  ≥ 0.47). Conclusion  Postoperative facial nerve outcome, hearing, tumor progression, and recurrence are similar for patients with CVSs and SVSs. As CVS growth patterns and responses to radiation are unpredictable, we favor microsurgical resection over radiosurgery as the initial treatment. NXY-059 mw Our data do not support the commonly held belief that cystic tumors behave more aggressively than solid tumors or are associated with increased postoperative facial nerve deficits.Introduction  Neurosurgical anatomy is traditionally taught via anatomic and operative atlases; however, these resources present the skull base using views that emphasize three-dimensional (3D) relationships rather than operative perspectives, and are frequently written above a typical resident's understanding. Our objective is to describe, step-by-step, a retrosigmoid approach dissection, in a way that is educationally valuable for trainees at numerous levels. Methods  Six sides of three formalin-fixed latex-injected specimens were dissected under microscopic magnification. A retrosigmoid was performed by each of three neurosurgery residents, under supervision by the senior authors (C.L.W.D. and M.J.L.) and a graduated skull base fellow, neurosurgeon, and neuroanatomist (M.P.C.). Dissections were supplemented with representative case applications. Results  The retrosigmoid craniotomy (aka lateral suboccipital approach) affords excellent access to cranial nerve (CN) IV to XII, with corresponding applicability to numerous posterior fossa operations. Key steps include positioning and skin incision, scalp and muscle flaps, burr hole and parasigmoid trough, craniotomy flap elevation, initial durotomy and deep cistern access, completion durotomy, and final exposure. Conclusion  The retrosigmoid craniotomy is a workhorse skull base exposure, particularly for lesions located predominantly in the cerebellopontine angle. Operatively oriented neuroanatomy dissections provide trainees with a critical foundation for learning this fundamental skull base technique. We outline a comprehensive approach for neurosurgery residents to develop their familiarity with the retrosigmoid craniotomy in the cadaver laboratory in a way that simultaneously informs rapid learning in the operating room, and an understanding of its potential for wide clinical application to skull base diseases.