Endoscope-Assisted, Transmastoid, High Cervical Approach for Resection of a Jugular Foramen Schwannoma: 2-Dimensional Operative Video.

Jugular foramen schwannomas (JFSs) are relatively rare, benign lesions that account for 10% to 30% of all tumors in the region of the jugular foramen. Given their slow-growing nature, JFSs can become quite large before causing symptoms of lower cranial nerve (LCN) dysfunction, making microsurgical resection a challenge. Successful resection of any JFS is dependent on the identification and preservation of the adjacent, uninvolved LCNs to alleviate nerve compression and preserve function. We report a transmastoid, high cervical approach to a dumbbell-shaped, extracranial JFS that was causing symptomatic LCN compression. The patient presented with dysphagia and was found to have left vocal cord paralysis on video laryngoscopy and intermittent aspiration on a swallowing evaluation. The transmastoid, high cervical exposure allowed for early identification of the tumor as well as the adjacent LCNs. Neurophysiological monitoring included somatosensory evoked potentials; brainstem auditory evoked responses; and cranial nerve VII, X, XI, and XII electromyographic monitoring. Endoscopic assistance allowed for improved LCN visualization from the high cervical exposure and gross-total resection of the tumor. The patient\u27s dysphagia improved both subjectively and objectively following the resection. The patient gave written informed consent for surgery and publication of the case report. Institutional review board approval was not required for this case report. Used with permission from Barrow Neurological Institute

Defining a Standardized Approach for the Bedside Insertion of Temporal Horn External Ventricular Drains: Procedure Development and Case Series

BACKGROUND: A trapped temporal horn can be emergently decompressed by inserting a bedside temporal horn external ventricular drain (tEVD). However, no standardized method for this procedure has been described. OBJECTIVE: To identify methods for bedside tEVD insertion, and determine the safest, most accurate, and most easily standardized approach. METHODS: Volumetric images of 20 patients with trapped temporal horns were analyzed. Three tEVD approaches (perpendicular, lateral, and medial) were defined, along with standardized insertion points and external landmarks for trajectory guidance. Predicted success in penetrating the temporal horn, skin-to-temporal horn entrance distance, temporal horn distance traversed, and trajectory target error and accuracy were evaluated; data were compared with independent sample t tests. RESULTS: Nineteen of 20 cases were analyzed; 13 had critical temporal horn entrapment. Penetration was achieved in 100% of perpendicular and 84% (16/19) of lateral and medial approaches (92% [12/13] of critical entrapments). In 19 patients, trajectory error was not significantly different among approaches. The perpendicular approach had significantly more accuracy than the lateral (P = .01) and medial (P = .002) approaches. The lateral approach afforded significantly more traversable distance than the perpendicular approach (P = .009). In cases with critical entrapment, the perpendicular approach had significantly less error (P = .02) and significantly better accuracy (P = .02) than the medial approach. The perpendicular approach trended toward more accuracy than the lateral approach (P = .06). CONCLUSION: The perpendicular approach appears to be the easiest, safest, and most reliable approach tested. We recommend conducting bedside tEVD placement only in patients with a critically dilated temporal horn who are clinically deteriorating at a rate that prohibits other procedures

Choristoma of the vestibular nerve: Should it influence our management of vestibular Schwannoma- Case report and review of the literature

Background and Importance: Choristomas of the internal auditory canal and cerebellopontine angle are rare, non-neoplastic lesions that mimic vestibular schwannomas and may subsequently be subject to treatment by surgical resection or radiosurgery. Their management is conservative with observation. Surgical intervention has been associated with expected hearing loss that is counter to the goal of surgery. On the other hand, radiosurgery is not indicated in such pathology and will also lead to eventual hearing loss.</p

Safety and Accuracy of Freehand Versus Navigated Iliac Screws: Results From 222 Screw Placements

Study Design. Retrospective review. Objective. To compare the safety and accuracy of the freehand technique versus stereotactic navigation for placement of iliac screws. Summary of Background Data. Iliac screw fixation is often used to augment lumbosacral reconstruction in advanced spine disease to increase the likelihood of successful arthrodesis. Iliac screws can be placed with image guidance, using either intraoperative fluoroscopy or computed tomography (CT) to guide navigation. However, these imaging modalities add radiation exposure and can disrupt workflow. The freehand technique is an alternative strategy that decreases radiation exposure and workflow disruption but may compromise safety and accuracy. Methods. A retrospective review was performed for a consecutive series of adult patients with degenerative spine conditions who underwent posterior reconstruction with iliac screw placement between 2011 and 2016. Clinical and radiographic data were collected and analyzed. The accuracy of iliac screw placement was determined with either intraoperative/postoperative CT imaging or anteroposterior/lateral radiography when CT was not performed. Results. Bilateral iliac screws were placed in all 111 patients, for a total of 222 iliac screws. Eighty screws were placed with the freehand technique and 142 with the intraoperative navigation technique. CT imaging was used to assess placement accuracy of 124 screws (46 freehand [37%], 78 navigated [63%]). Accuracy was similar for the freehand group (89%, 41/46) and the navigated group (96%, 75/78) (P = 0.12). For patients without intraoperative/postoperative CT imaging, radiography was used to assess placement accuracy of 98 screws (34 freehand, 64 navigated) and the placement accuracy rate for the freehand group (100%, 34/34) was comparable to that for the navigated group (98%, 63/64) (P = 0.46). No complications attributable to iliac screw placement occurred in either group. Conclusion. Overall, there was no difference in the safety and accuracy between the freehand and navigated techniques

Spinal Arteriovenous Malformation Associated With Schimmelpenning Syndrome: Case Report

The authors report the presentation and management of a 13-year-old girl with Schimmelpenning syndrome, a rare neurocutaneous syndrome; this patient suffered hemorrhage of a spinal arteriovenous malformation. This is the first case of a spinal arteriovenous malformation reported in association with Schimmelpenning syndrome. Neurosurgeons should be aware of this rare phacomatosis as well as of the various neurological disorders associated with this diagnosis. The threshold for imaging the neuraxis in these patients should be low. ©AANS, 2013

Dissection of the Petrosal Presigmoid-Retrolabyrinthine Approach for the Petroclival Region on a Cadaver: 2-Dimensional Operative Video.

Skull base epidermoid tumors, meningiomas, and schwannomas can be accessed by different techniques depending on the location and size of the lesion. Small lesions located anterior to the internal acoustic meatus (IAM) can be accessed via the subtemporal approach, and lesions located posterior to the IAM can be approached via retrosigmoid craniotomy. However, expansive lesions that are located anterior to the IAM and extend posteriorly toward the lower clivus can be accessed via the petrosal approach. The petrosal approach (presigmoid-retrolabyrinthine) is centered on the petrous ridge of the temporal bone and is mainly performed for intradural lesions located at the clivus and petroclivus junction area. Patients with intact hearing can benefit from this technique, as the labyrinth is untouched and yet the middle and posterior fossa compartments are connected. Additionally, extension of the lesion from the suprasellar area/cavernous sinus to the foramen magnum can be dissected and removed. There are variations of the petrosal approach, such as translabyrinthine, transotic, and transchoclear, with which hearing cannot be preserved, and the transcrusal approach, wherein posterior and superior semicircular canals are sacrificed yet hearing preserved. The endolymphatic duct is usually transected and not reapproximated. Neurotology input is always helpful when dealing with inner ear structures.  This complex approach demands exhaustive practice with temporal bone dissection in a cadaver laboratory. Although this approach can be extended anteriorly, combination with an anterior petrosal approach permits more rostral exposure. In this video, we demonstrate the stepwise dissection of the posterior petrosal approach only, showing procedure nuances in a cadaver.1-8Used with permission from Barrow Neurological Institute, Phoenix, Arizona