Intralabyrinthine schwannomas (ILSs) are rare tumors involving the otic capsule. Notably, they are often misdiagnosed because their symptoms mimic those of other, more common inner ear pathologies. Diagnosis requires high-resolution contrast-enhanced magnetic resonance imaging (MRI), which reveals filling defects (using a T2-weighted MRI sequence) or focal enhancement (using a T1-weighted MRI sequence with gadolinium enhancement) in the inner ear. A 52-year-old male patient with intractable vertigo or single-sided deafness should raise suspicion of this clinical entity as a differential diagnosis. Translabyrinthine excision of the tumor along with auditory rehabilitation using a cochlear implant can provide good outcomes with minimal morbidity in carefully selected cases. Here, we present an interesting case of a transmodiolar ILS mimicking Meniere\'s disease, wherein surgery using the translabyrinthine approach and an extended cochleostomy yielded favorable outcomes.

Objective  The evolution of acoustic neuroma (AN) care continues to shift focus on balancing optimized tumor resection and control with preservation of neurological function. Prior learning curve analyses of AN resection have demonstrated a plateau between 20 and 100 surgeries. In this study of 860 consecutive AN surgeries, we investigate the presence of an extended learning curve tail for AN resection. Methods  A retrospective cohort study of AN resections by a single interdisciplinary team between 1988 and 2018 was performed. Proportional odds models and restricted cubic splines were used to determine the association between the timing of surgery and odds of improved postoperative outcomes. Results  The likelihood of improved postoperative House-Brackmann (HB) scores increased in the first 400 procedures, with HB 1 at 36% in 1988 compared with 79% in 2004. While the probability of a better HB score increased over time, there was a temporary decrease in slope of the cubic spline between 2005 and 2009. The last 400 cases continued to see improvement in optimal HB outcomes: adjusted odds of HB 1 score were twofold higher in both 2005 to 2009 (adjusted odds ratio [aOR]: 2.11, 95% confidence interval [CI]: 1.38-3.22, p  < 0.001) and 2010 to 2018 (aOR: 2.18, 95% CI: 1.49-3.19, p  < 0.001). Conclusion  In contrast to prior studies, our study demonstrates the steepest growth for learning, as measured by rates of preservation of facial function outcomes (HB 1), occurs in the first 400 AN resections. Additionally, improvements in patient outcomes continued even 30 years into practice, underlining the importance of lifelong learning.

Objective  An operative workflow systematically compartmentalizes operations into hierarchal components of phases, steps, instrument, technique errors, and event errors. Operative workflow provides a foundation for education, training, and understanding of surgical variation. In this Part 1, we present a codified operative workflow for the retrosigmoid approach to vestibular schwannoma resection. Methods  A mixed-method consensus process of literature review, small-group Delphi\'s consensus, followed by a national Delphi\'s consensus, was performed in collaboration with British Skull Base Society (BSBS). Each Delphi\'s round was repeated until data saturation and over 90% consensus was reached. Results  Eighteen consultant skull base surgeons (10 neurosurgeons and 8 ENT [ear, nose, and throat]) with median 17.9 years of experience (interquartile range: 17.5 years) of independent practice participated. There was a 100% response rate across both Delphi\'s rounds. The operative workflow for the retrosigmoid approach contained three phases and 40 unique steps as follows: phase 1, approach and exposure; phase 2, tumor debulking and excision; phase 3, closure. For the retrosigmoid approach, technique, and event error for each operative step was also described. Conclusion  We present Part 1 of a national, multicenter, consensus-derived, codified operative workflow for the retrosigmoid approach to vestibular schwannomas that encompasses phases, steps, instruments, technique errors, and event errors. The codified retrosigmoid approach presented in this manuscript can serve as foundational research for future work, such as operative workflow analysis or neurosurgical simulation and education.

Objective  An operative workflow systematically compartmentalizes operations into hierarchal components of phases, steps, instrument, technique errors, and event errors. Operative workflow provides a foundation for education, training, and understanding of surgical variation. In this Part 2, we present a codified operative workflow for the translabyrinthine approach to vestibular schwannoma resection. Methods  A mixed-method consensus process of literature review, small-group Delphi\'s consensus, followed by a national Delphi\'s consensus was performed in collaboration with British Skull Base Society (BSBS). Each Delphi\'s round was repeated until data saturation and over 90% consensus was reached. Results  Seventeen consultant skull base surgeons (nine neurosurgeons and eight ENT [ear, nose, and throat]) with median of 13.9 years of experience (interquartile range: 18.1 years) of independent practice participated. There was a 100% response rate across both the Delphi rounds. The translabyrinthine approach had the following five phases and 57 unique steps: Phase 1, approach and exposure; Phase 2, mastoidectomy; Phase 3, internal auditory canal and dural opening; Phase 4, tumor debulking and excision; and Phase 5, closure. Conclusion  We present Part 2 of a national, multicenter, consensus-derived, codified operative workflow for the translabyrinthine approach to vestibular schwannomas. The five phases contain the operative, steps, instruments, technique errors, and event errors. The codified translabyrinthine approach presented in this manuscript can serve as foundational research for future work, such as the application of artificial intelligence to vestibular schwannoma resection and comparative surgical research.

Objective  To highlight the advantages and disadvantages of the combined translabyrinthine (TL) and classic retrosigmoid (RS) approaches. Design  Retrospective chart review. Setting  National tertiary referral center for skull base pathology. Participants  Twenty-two patients with very large cerebellopontine angle tumors were resected using the combined TL-RS approach. Main Outcome Measures  Preoperative patient characteristics including age, sex, and hearing loss. Tumor characteristics, pathology, and size. Intraoperative outcome: tumor removal. Postoperative outcomes included facial nerve function, residual tumor growth, and neurological deficits. Results  Thirteen patients had schwannoma, eight had meningioma, and one had both. The mean age was 47 years, mean tumor size was 39 × 32 × 35 mm (anterior-posterior, medial-lateral, craniocaudal), and mean follow-up period was 80 months. Tumor control was achieved in 13 patients (59%), and 9 (41%) had residual tumor growth that required additional treatment. Seventeen patients (77%) had postoperative House-Brackmann (H-B) facial nerve function grades I to II, one had H-B grade III, one H-B grade V, and three H-B grade VI. Conclusion  Combining TL and RS approaches may be helpful in safely removing large meningiomas and schwannomas in selected cases. This valuable technique should be considered when sufficient exposure cannot be achieved with the TL or RS approach alone.

Intravestibular schwannomas are rare tumors within the intralabyrinthine region and involve different management considerations compared to more common vestibular schwannomas. In this report, the authors review a case of a 52-year-old woman who presented with hearing loss and vestibular symptoms and was found to have a left intravestibular schwannoma. Given her debilitating vestibular symptoms, she underwent microsurgical resection. In this video, the authors review the relevant anatomy, surgical technique, and management considerations in these patients. The video can be found here: https://stream.cadmore.media/r10.3171/2021.7.FOCVID2187.

The natural history of neurofibromatosis type 2 (NF2) is profound bilateral hearing loss. The decision to pursue microsurgery may be more complicated in NF2 than with sporadic tumors. Schwannomas in NF2 often occur with other skull base tumors. Treatment should be tailored to preserve auditory perception for as long as possible. The authors present the case of a man with NF2 and a vestibular schwannoma who has poor hearing on the same side as a large petrous apex meningioma, both opposite to a well-hearing ear. This case highlights surgical decision-making and technical nuances during resection of collision tumors in NF2. The video can be found here: https://stream.cadmore.media/r10.3171/2021.7.FOCVID21130.

Objective  This study was aimed to evaluate the impact of a multidisciplinary perioperative pathway on length of stay (LOS) and postoperative outcomes after vestibular schwannoma surgery. Setting  This study was conducted in a tertiary skull base center. Main Outcome Measures  The impact of the pathway on intensive care unit (ICU) LOS was evaluated as the primary outcome measure of the study. Overall resource LOS, postoperative complications, and readmission rates were also evaluated as secondary outcome measures. Methods  Present study is a retrospective review. Results  A universally adopted perioperative pathway was developed to include standardization of preoperative education and expectations, intraoperative anesthetic delivery, postoperative nursing education, postoperative rehabilitation, and utilization of stepdown and surgical floor units after ICU stay. Outcomes were measured for 95 consecutive adult patients who underwent surgical resection for vestibular schwannoma (40 cases before implementation of the perioperative pathway and 55 cases after implementation). There were no significant differences in the two groups with regard to tumor size, operative time, or medical comorbidities. The mean ICU LOS decreased from 2.1 in the preimplementation group to 1.6 days in the postimplementation group ( p  = 0.02). There were no significant differences in overall resource LOS postoperative complications or readmission rates between groups. Conclusion  Multidisciplinary, perioperative neurotologic pathways can be effective in lowering ICU LOS in patients undergoing vestibular schwannoma surgery without compromising quality of care. Further research is needed to continue to sustain and continuously improve these and other measures, while continuing to provide high-quality care to this patient population.

Introduction  While regarded as an effective surgical approach to vestibular schwannoma (VS) resection, the translabyrinthine (TL) approach is not without complications. It has been postulated that postoperative cerebral venous sinus thrombosis (pCVST) may occur as a result of injury and manipulation during surgery. Our objective was to identify radiologic, surgical, and patient-specific risk factors that may be associated with pCVST. Methods  The Institutional Review Board (IRB) approval was obtained and the medical records of adult patients with VS who underwent TL craniectomy at University Hospitals Cleveland Medical Center between 2009 and 2019 were reviewed. Demographic data, radiographic measurements, and tumor characteristics were collected. Outcomes assessed included pCVST and the modified Rankin score (mRS). Results  Sixty-one patients ultimately met inclusion criteria for the study. Ten patients demonstrated radiographic evidence of thrombus. Patients who developed pCVST demonstrated shorter internal auditory canal (IAC) to sinus distance (mean: 22.5 vs. 25.0 mm, p  = 0.044) and significantly smaller petrous angles (mean: 26.3 vs. 32.7 degrees, p  = 0.0045). Patients with good mRS scores (<3) appeared also to have higher mean petrous angles (32.5 vs. 26.8, p  = 0.016). Koos\' grading and tumor size, in our study, were not associated with thrombosis. Conclusion  More acute petrous angle and shorter IAC to sinus distance are objective anatomic variables associated with pCVST in TL surgical approaches.

OBJECTIVE: Report our experience in the management of posterior petrous surface meningiomas (PPSMs), and identify features that affect hearing, facial nerve (FN) function, and control of the disease.
METHODS: Retrospective case series of 131 patients surgically managed for PPSMs. FN status, hearing and tumour radicality were assessed and compared between patients with tumours of different locations (Desgeorges classification) and internal auditory canal involvement (IAC).
RESULTS: At the time of surgery 74.8% of patients had a hearing loss. Hearing was mostly unserviceable in tumors attached to the meatus. Pure tone audiometry did not correlate to IAC extension, while speech discrimination scores were statistically worse when the tumor occupied the IAC (unpaired t test, p = 0.0152). Similarly, extrameatal tumors undergoing removal by otic preserving techniques maintained postoperative hearing, whereas hearing worsened significantly in tumors involving the IAC (paired t test, p = 0.048). The FN was affected preoperatively in 11.4% of cases. Postoperative FN palsy was significantly correlated to the IAC involvement (Fisher\'s exact test, p = 0.0013), while it was not correlated to tumor size. According to the Desgeorges classification, a postoperative FN palsy complicated the majority of anteriorly extending tumors and, two-fifths of meatus centred tumors. 75% of posterior located tumors had a postoperative FN grade I HB.
CONCLUSIONS: Since the involvement of the IAC by the tumor affects both hearing and FN function, the IAC is of primary importance in PPSMs and should be studied and addressed as much as the tumor location in the CPA.