First described and successfully resected by De Martel et al in 1993,1 hypoglossal schwannomas are rare skull base lesions that can develop at any level of the hypoglossal nerve.2 In up to 50% of cases, they reach a large size with a dumbbell shape with intracranial and extracranial components and a scalloped hypoglossal canal.2 Accordingly, they may lead to brainstem compression and progressive cranial nerves dysfunction.2-4 Given the relatively frequent recurrences after partial resections, the goal of surgery is gross total resection with preservation of lower cranial nerves function.2,5,6 Adequate exposure is the key to total surgical removal with preservation of the vital neurovascular structures. The dumbbell-shaped ones require a skull base approach that renders both the intracranial and extracranial parts amenable for resection. The soft avascular suckable nature of the tumor and the expanded hypoglossal canal facilitate the dissection and resection. Endoscopic-assisted resection is particularly beneficial in these cases allowing the surgeon to simultaneously alternate between microsurgical and endoscopic visualization. With the advent of modern neurosurgical techniques, outcomes of hypoglossal schwannoma resections have been rewarding.6 We report the case of a 20-year-old man who presented with progressively worsening dysphasia leading to the diagnosis of a large dumbbell-shaped hypoglossal schwannoma. The tumor was resected through a skull base approach including cervical dissection.7 The patient consented to the surgery and publication of his images. Image at 1:55 from Al-Mefty and Teixeira,8 with permission from JNSPG.

Transsphenoidal endoscopic endonasal surgery (EES) provides effective treatment for patients with lesions of the sella turcica. The endoscopic technique requires different instrumentation, which depends on the gross anatomy of the nasal cavity. The treatment of lateral lesions is more challenging in EES. To evaluate the effect of preoperative simulation using multiple anatomic landmarks. Pre- and postoperative tumor volumes were analyzed in 33 patients with nonfunctioning pituitary adenomas who underwent EES (Knosp grades 3 and 4). The surgical working angle and space were three-dimensionally simulated at the plane of the anterior/posterior surgical field (tuberculum sellae/posterior clinoid process) using multiple anatomic landmarks of high-resolution computed tomography scans, such as nasal piriform aperture (proximal surgical corridor), and the width of bilateral vidian canals or lamina perpendicularis of palatine bone (distal surgical corridor). Receiver operating characteristic curves for the removed tumor volume were used to determine the cutoff value for the simulated working angle and space. Simulated working space at the plane of tuberculum sellae using piriform aperture and lamina perpendicularis of palatine bone was associated with the removed tumor volume in the cavernous sinus. Patients with a larger working space (≥42.7 mm) significantly showed a higher removed tumor volume ( P = .023). There was no relationship between other parameters and the removed tumor volume. A new method to predict the surgical field for cavernous sinus lesions around sella turcica was successfully established. Further studies are needed to define and expand applications of this simulation method.

Dorsal intradural arteriovenous fistulas (DI-AVFs) represent 80% of spinal AVFs. Microsurgical clip occlusion is a durable treatment that uses preoperative and postoperative digital subtraction angiography (DSA) as standard practice. Intraoperative indocyanine green videoangiography (ICG-VA) is a valuable intraoperative adjunct in these cases. Intraoperative ICG-VA findings have not been compared with postoperative DSA findings. To assess the diagnostic value of intraoperative ICG-VA vs postoperative DSA for spinal DI-AVFs. A multi-institutional database of vascular malformations was queried for all surgically managed cases of DI-AVF. Patients with both intraoperative ICG-VA and postoperative DSA were included. Demographic and radiologic data, intraoperative findings, and surgical outcomes data were retrospectively analyzed. Forty-five patients with DI-AVF were identified (male sex, 32; mean age, 61.9 [range, 26-85] years). All DI-AVFs were treated with interruption of the fistula with clip occlusion of the draining vein. Intraoperative ICG-VA showed complete obliteration in all patients. Postoperative DSA was performed for 40 patients and confirmed complete obliteration in all patients. The negative predictive value of ICG-VA confirming complete occlusion of the DI-AVFs was 100%. Eighteen patients (47%) experienced clinical improvement, and 16 (42%) experienced no change in condition. ICG-VA is useful for intraoperative identification of DI-AVFs and confirmation of complete microsurgical occlusion. Correlation between intraoperative ICG-VA and postoperative DSA findings demonstrates the diagnostic power of ICG-VA. This finding suggests that postoperative DSA is unnecessary when intraoperative ICG-VA confirms complete occlusion of the DI-AVF, which will spare patients the procedural risk and cost of this invasive procedure.

Idiopathic intracranial hypertension (IIH) can cause debilitating symptoms and optic nerve ischemia if untreated. Cerebrospinal fluid diversion is often necessary to reduce intracranial pressure; however, current ventriculoperitoneal and lumboperitoneal shunting techniques have high failure rates in patients with IIH. To describe our experience treating IIH with a novel stereotactic-guided transcerebellar cisternoperitoneal shunt (SGTC-CPS) technique that places the proximal shunt catheter in the posterior cisterna magnum. Retrospective perioperative and postoperative data from all patients who underwent SGTC-CPS placement for IIH from March 1, 2015, to December 31, 2020, were analyzed. Patients were positioned as for ventriculoperitoneal shunt placement but with the head turned farther laterally to adequately expose the retrosigmoid space. Using neuronavigation, an opening was made near the transverse-sigmoid junction, and the proximal catheter was inserted transcerebellarly into the posterior foramen magnum. Thirty-two patients underwent SGTC-CPS placement (29 female; mean body mass index, 36.0 ± 7.5; 14 with prior shunt failures). The mean procedure time for shunt placement was 145 minutes. No intraoperative complications occurred, and all patients were discharged uneventfully. At the 6-month follow-up, 81% of patients (21 of 26) had relief of their presenting symptoms. Shunt survival without revision was 86% (25 of 29) at 1 year and 67% (10 of 15) at 3 years, with no infections. The SGTC-CPS offers an alternative solution for cerebrospinal fluid diversion in patients with IIH and demonstrates a lower failure rate and more durable symptom relief compared with ventriculoperitoneal or lumboperitoneal shunt placement. Using proper techniques and equipment promotes safe and facile placement of the proximal catheter.

Haynes, Joseph BA*; Sadek, Mikel MD‡; Raz, Eytan MD, PhD§; Levine, Jamie MD‖; Shapiro, Maksim MD§; Delavari, Nader MD¶; Riina, Howard A. MD¶; Nelson, Peter Kim MD§; Favate, Albert MD#; Nossek, Erez MD* Author Information

Khan, Nickalus MD; Wu, Eva M. MD; Jamshidi, Aria M. MD; Morcos, Jacques MD Author Information

Persistent cerebrospinal fluid (CSF) egress after durotomy in posterior thoracic or lumbar spine surgery may cause devastating complications. Persistent CSF leaks may require reoperation, which confers additional cost and morbidity. To evaluate the efficacy of our subfascial epidural drainage protocol in the setting of durotomy to prevent reoperation. A retrospective cohort study of drained and undrained cohorts was completed to identify factors associated with reoperation for persistent CSF leak-related symptoms. The efficacy and safety of this 7-day subfascial epidural drainage protocol was assessed by comparing reoperation incidence, perioperative complications, rehabilitation necessity, and readmissions. In total, 156 patients underwent subfascial epidural drainage, and 14 were not drained. Subfascial drainage for up to 7 days was associated with a significantly lower incidence of reoperation than no drainage (3.3% vs 14%, respectively; P = .03). Perioperative complication incidence was similar between cohorts (12.8% vs 21.4%, respectively; P = .37), and length of stay was unchanged regardless of drainage (median 7 days). Subfascial drainage conferred a nearly 2-fold relative risk reduction in inpatient rehabilitation requirement (RR 0.55) and 3-fold relative risk reduction in 30-day (RR 0.31) and 90-day readmission (RR 0.36). Factors associated with reoperation among drained patients included drainage longer than 7 days, tobacco use, age younger than 50 years, and longer segment operations. Revision spine surgery was associated with reoperation among undrained patients. When followed after durotomy, our subfascial epidural drainage protocol results in fewer reoperations than in an undrained cohort without prohibitive cost and no added morbidity.

Minimally invasive surgery (MIS) for intracranial pathology minimizes surgical morbidity but can come at the cost of operator ergonomics and technical surgical success. Here, the authors present a case series to report the first use of a novel 15-mm tubular retraction system with integrated lighting and visualization capabilities for MIS access to intracranial lesions. To demonstrate feasibility and effectiveness of the 15-mm Aurora Surgiscope (Integra Lifesciences) for intracranial MIS approaches. The 15-mm Aurora Surgiscope facilitated MIS approach to gain access to intraparenchymal pathologies. The device consists of a tubular access system with integrated light source and a reusable control unit that modifies video parameters. The port was inserted along a preplanned trajectory through a mini-craniotomy. Bimanual access allowed the surgeon to comfortably dissect/resect lesional tissue using high-quality video. Four patients are presented. In cases 1 and 2, the authors evacuated acute intracerebral hemorrhages. Both had <15 cc hemorrhage with improved or stable neurological examination. In case 3, the authors performed gross total resection of a cerebellar pilocytic astrocytoma. In case 4, the authors resected a mesial posterior temporal cavernoma. No perioperative/technical complications were noted. The Aurora Surgiscope system is a novel integrated tubular retraction, lighting, and visualization system that allows access to a wide variety of pathologies using a MIS approach. The Surgiscope allows the surgeon to use bimanual dexterity through a small access port while limiting the need for additional equipment such as microscope, exoscope, or endoscope.

Endovascular embolization using Onyx has been a major advancement in the treatment of cerebrovascular malformations. Microcatheter entrapment in Onyx is a procedural complication which can pose a thromboembolic risk to patients. There have been 4 retrieval techniques for intact microcatheters entrapped in Onyx previously described in the literature, which are summarized in this report. We present the first case using a novel stentriever-assisted technique to successfully and safely retrieve a fractured microcatheter entrapped in Onyx. An adult patient with a Cognard IIa + b dural arteriovenous fistula (dAVF) underwent Onyx embolization. The microcatheter became entrapped and fractured while initially attempting removal. A stentriever was used off label to capture the fractured microcatheter and then a larger caliber microcatheter was railroaded over it. Retrieval of the fractured microcatheter by the stentriever was then facilitated by counter traction on the Onyx cast using the larger microcatheter. This novel stentriever-assisted technique is a safe and effective rescue maneuver for retrieving a fractured microcatheter trapped in Onyx during embolization of dAVF. There is a need for further research and development of novel devices for retrieval of entrapped microcatheters.

Precise communication between neurosurgeons and pathologists is crucial for optimizing patient care, especially for intraoperative diagnoses. Confocal laser endomicroscopy (CLE) combined with a telepathology software platform (TSP) provides a novel venue for neurosurgeons and pathologists to review CLE images and converse intraoperatively in real-time. To describe the feasibility of integrating CLE and a TSP in the surgical workflow for real-time review of in vivo digital fluorescence tissue imaging in 3 patients with intracranial tumors. Although the neurosurgeon used the CLE probe to generate fluorescence images of histoarchitecture within the operative field that were displayed on monitors in the operating room, the pathologist simultaneously remotely viewed the CLE images. The neurosurgeon and pathologist discussed in real-time the histological structures of intraoperative imaging locations. The neurosurgeon placed the CLE probe at various locations on and around the tumor, in the surgical resection bed, and on surrounding brain tissue with communication through the TSP. The neurosurgeon oriented the pathologist to the location of the CLE, and the pathologist and neurosurgeon discussed the CLE images in real-time. The TSP and CLE were integrated successfully and rapidly in the operating room in all 3 cases. No patient had perioperative complications. Two novel digital neurosurgical cellular imaging technologies were combined with intraoperative neurosurgeon-pathologist communication to guide the identification of abnormal histoarchitectural tissue features in real-time. CLE with the TSP may allow rapid decision-making during tumor resection that may hold significant advantages over the frozen section process and surgical workflow in general.