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Objective: Exclusive endoscopic (EETTA) and expanded (ExpTTA) transcanal transpromontorial approaches have shown promising results for treating internal auditory canal (IAC) lesions. We reviewed the literature to answer the question: "Do EETTA and ExpTTA achieve high rates of complete resection and low rates of complications in treating patients with IAC pathologies?", Data Sources: PubMed, EMBASE, Scopus, Web of Science, and Cochrane were searched., Review Methods: Studies reporting EETTA/ExpTTA for IAC pathologies were included. Indications and techniques were discussed and meta-analyzed rates of outcomes and complications were obtained with random-effect model meta-analyses., Results: We included 16 studies comprising 173 patients, all with non-serviceable hearing. Baseline FN function was mostly House-Brackmann-I (96.5%; 95% CI: 94.9-98.1%). Most lesions were vestibular/cochlear schwannomas (98.3%; 95% CI: 96.7-99.8%) of Koos-I (45.9%; 95% CI: 41.3-50.3%) or II (47.1%; 95% CI: 43-51.1%). EETTA was performed in 101 patients (58.4%; 95% CI: 52.4-64.3%) and ExpTTA in 72 (41.6%; 95% CI: 35.6-47.6%), achieving gross-total resection in all cases. Transient complications occurred in 30 patients (17.3%; 95% CI: 13.9-20.5%), with meta-analyzed rates of 9% (95% CI: 4-15%), comprising FN palsy with spontaneous resolution (10.4%; 95% CI: 7.7-13.1%). Persistent complications occurred in 34 patients (19.6%; 95% CI: 17.1-22.2%), with meta-analyzed rates of 12% (95% CI: 7-19%), comprising persistent FN palsy in 22 patients (12.7%; 95% CI: 10.2-15.2%). Mean follow-up was 16 months (range, 1-69; 95% CI: 14.7-17.4). Post-surgery FN function was stable in 131 patients (75.8%; 95% CI: 72.1-79.5%), worsened in 38 (21.9%; 95% CI: 18.8-25%), and improved in 4 (2.3%; 95% CI: 0.7-3.9%), with meta-analyzed rates of improved/stable response of 84% (95% CI: 76-90%)., Conclusion: Transpromontorial approaches offer newer routes for IAC surgery, but their restricted indications and unfavorable FN outcomes currently limit their use. Laryngoscope, 133:2856-2867, 2023., (© 2023 The American Laryngological, Rhinological and Otological Society, Inc.)

Objective: Examine the effects of a multi-disciplinary skull base conference (MDSBC) on the management of patients seen for skull base pathology in a neurotology clinic., Methods: Retrospective case review of patients who were seen in a neurotology clinic at a tertiary academic medical center for pathology of the lateral skull base and were discussed at an MDSBC between July 2019 and February 2020. Patient characteristics, nature of the skull base pathology, and pre- and post-MDSBC plan of care was categorized., Results: A total of 82 patients with pathology of the lateral skull base were discussed at a MDSBC during an 8-month study period. About 54 (65.9%) had a mass in the internal auditory canal and/or cerebellopontine angle while 28 (34.1%) had other pathology of the lateral skull base. Forty-nine (59.8%) were new patients and 33 (40.2%) were established. The management plan changed in 11 (13.4%, 7.4-22.6 95% CI) patients as a result of the skull base conference discussion. The planned management changed from some form of treatment to observation in 4 patients, and changed from observation to some form of treatment in 4 patients. For 3 patients who underwent surgery, the planned approach was altered., Conclusions: For a significant proportion of patients with pathology of the lateral skull base, the management plan changed as a result of discussion at an MDSBC. Although participants of a MDSBC would agree of its importance, it is unclear how an MDSBC affects patient outcomes.

Objective: The aim of this study was to determine the incidence of cochlear fibrosis after vestibular schwannoma (VS) resection via middle cranial fossa (MCF) approach., Design: A retrospective case review was conducted., Setting: The review was conducted in a tertiary care academic medical center., Participants: Patients who (1) underwent resection of VS via MCF approach between 2013 and 2018, (2) had complete pre- and post-audiometric testing, and (3) had clinical follow-up with magnetic resonance imaging (MRI) for at least 1 year after surgery were included., Main Outcome Measure(s): The main outcome of this study was cochlear fibrosis as assessed by MRI 1 year after surgery., Results: Fifty-one patients underwent VS resection via MCF technique during the study period. Of 31 patients with AAO-HNS class A or B preoperative hearing ability, 18 (58.0%) maintained class A, B, or C hearing postoperatively. Of 16 patients who lost hearing and had MRI 1 year after surgery, 11 (61.1%) had MRI evidence of fibrosis in at least some portion of the labyrinth and 4 (22.2%) showed evidence of cochlear fibrosis. Of 16 patients with preserved hearing and MRI 1 year after surgery, 4 (25%) had fibrosis in some portion of the labyrinth, with no fibrosis in the cochlea., Conclusions: In patients who lose hearing during VS resection with the MCF approach, there is usually MRI evidence of fibrosis in the labyrinth 1 year after surgery. However, there is also, but less commonly, fibrosis involving the cochlea. It is unclear if this will affect the ability to insert a cochlear implant electrode array., (© 2022 S. Karger AG, Basel.)

Patients diagnosed with neurofibromatosis type 2 (NF2) are extremely likely to develop meningiomas, in addition to vestibular schwannomas. Meningiomas are a common primary brain tumor; many NF2 patients suffer from multiple meningiomas. In NF2, patients have mutations in the NF2 gene, specifically with loss of function in a tumor-suppressor protein that has a number of synonymous names, including: Merlin, Neurofibromin 2, and schwannomin. Merlin is a 70 kDa protein that has 10 different isoforms. The Hippo Tumor Suppressor pathway is regulated upstream by Merlin. This pathway is critical in regulating cell proliferation and apoptosis, characteristics that are important for tumor progression. Mutations of the NF2 gene are strongly associated with NF2 diagnosis, leading to benign proliferative conditions such as vestibular schwannomas and meningiomas. Unfortunately, even though these tumors are benign, they are associated with significant morbidity and the potential for early mortality. In this review, we aim to encompass meningiomas and vestibular schwannomas as they pertain to NF2 by assessing molecular genetics, common tumor types, and tumor pathogenesis.

Objective: Compare outcomes of middle cranial fossa approach (MCF) to vestibular schwannoma (VS) resection in patients 60 years of age and older to patients under 60., Study Design: Retrospective case series., Setting: Tertiary referral center., Patients: Charts of 216 consecutive VS patients over 18 years of age were reviewed to identify 67 patients who underwent MCF approach to VS resection between 2006 and 2017., Intervention(s): Age at time of surgery., Main Outcome Measure(s): Measured outcomes included postoperative hearing results, facial nerve function, length of hospital stay, wound complications, cerebrospinal fluid leak, myocardial infarction, cerebrovascular accident, seizure, deep vein thrombosis, 30-day readmission, and return to operating room., Results: Sixty-seven patients underwent VS resection via MCF approach including 16 patients > = 60 years (mean 64.4 SD 3.3) and 51 patients < 60 years (mean 45.7 SD 10.2). Between these two groups, there were no differences in sex, tumor laterality, tumor size (10.4 mm versus 9.8 mm, p = 0.6), or other demographic characteristics. Postoperatively, there were no differences between groups in complication rates. Rates of HB 1 or 2 facial nerve function were similar (93.8% versus 88.2%, p = 0.7) as were rates of maintenance of class A or B hearing (58.3% versus 44.4%, p = 0.7)., Conclusions: Patients over 60 undergoing MCF for VS resection experienced similar rates of postoperative complications, facial nerve outcomes, and hearing preservation compared with younger patients. MCF for VS may be considered in the older population. Further research is warranted to evaluate appropriate limitations for this approach based on age.

Objective: To examine the association between operative duration and complications after vestibular schwannoma (VS) surgery., Study Design: Retrospective chart review., Setting: Tertiary referral center., Patients: One hundred forty-eight patients undergoing vestibular schwannoma resection in a single institution., Intervention: Vestibular schwannoma resection., Main Outcome Measures: Operative duration, surgical approach, tumor size, and postoperative complications., Results: Forty-one patients underwent middle cranial fossa (MCF) approach, 46 underwent translabyrinthine (TL) approach, and 61 underwent retrosigmoid (RS) approach. The mean operative duration overall was 407 minutes (MCF-339 min, TL-450 min, RS 420 min). When controlling for tumor size, there was no difference in procedure duration by approach (OR 0.92, CI 0.82-1.02, p=0.11).When controlling for approach, there was a significant increase in procedure duration by tumor size (OR 1.36, CI 1.23-1.50, p < 0.0001). Increased procedure duration was not associated with 30-day readmission (p = 0.82), cerebrospinal fluid leak (CSF) (p = 0.84), return to the operating room (p = 0.75), postoperative deep vein thrombosis (p = 1.0), postoperative stroke (p = 0.23), or postoperative wound complications (p = 0.70). Longer operative time was associated with increased hospital length of stay (p = 0.04). However, when controlling for tumor size and surgical approach, hospital length of stay was no longer associated with increased procedure duration (OR 1.15, CI 0.98-1.33, p = 0.3)., Conclusion: Increased operative duration was associated with larger tumor size; however contrary to previous reports, increased operative duration was not associated with postoperative complications.

Objective: Determine whether elevated body mass index (BMI) is associated with postoperative complications after vestibular schwannoma (VS) surgery., Study Design: Retrospective case series., Setting: Tertiary referral center., Patients: Two hundred six patients undergoing surgery for VS between 2010 and 2017, grouped into obese and nonobese patients., Intervention: Surgery for VS resection., Main Outcome Measures: Postoperative facial nerve outcomes, length of hospital stay, presence of postoperative cerebrospinal fluid leak, 30-day readmission, return to the operating room, wound complications, cardiovascular and thromboembolic complications., Results: After excluding 1 patient for missing BMI, our cohort included 205 patients. Seventy-nine patients (38.5%) were obese (mean BMI 36.2 kg/m, range 30-55.1) and the remaining 126 (61.5%) were nonobese (mean BMI 25.0, range 18.8-29.8 kg/m). Compared with nonobese patients, obesity was not associated with postoperative cerebrospinal fluid leak (OR 1.1, 95% CI 0.93-1.1), length of hospital stay (OR 0.98, 95% CI 0.65-1.47), 30-day readmission rates (1.04, 95% CI 0.95-1.14), return to operating room (OR 1.05, 95% CI 0.98-1.11), or other wound-related complications (OR 0.99, 95% CI 0.94-1.04)., Conclusion: In this cohort, elevated BMI was not associated with an increased risk for postoperative complications after VS surgery. Our findings may mitigate concerns associated with surgical management of VS in obese patients.

Background: The middle cranial fossa (MCF) approach is a challenging surgical technique for the resection of small and intermediate sized, primarily intracanalicular, vestibular schwannomas (VS), with the goal of hearing preservation (HP)., Objective: To describe a decade-long, single institutional experience with the MCF approach for resection of VS., Methods: This is a retrospective cohort study of 63 patients who underwent the MCF approach for resection of VS from 2006 to 2016. Audiometric data included pure-tone average (PTA), low-tone pure-tone average (LtPTA), word recognition score, and American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) hearing classification at presentation and follow-up. Patients with postoperative serviceable (AAO-HNS class A-B) and/or useful (AAO-HNS class A-C) hearing were compared to those without HP. Facial nerve function was assessed using the House-Brackmann scale., Results: The mean age and duration of follow-up were 50 ± 13 yr and 21 ± 21 mo, respectively. The mean tumor size was 10 ± 4 mm. The serviceable and usable HP rates were 54% and 50%, respectively. Some residual hearing was preserved in 71% of patients. Large tumor size (P = .05), volume (P = .03), and extrameatal tumor extension (P = .03) were associated with poor audiometric outcomes. The presence of a fundal fluid cap (P = .01) was a favorable finding. At definitive testing, LtPTA was significantly better preserved than traditional PTA (P = .01). Facial nerve outcomes, tumor control rates, and durability of audiometric outcomes were excellent. 47% of patients pursued aural rehabilitation., Conclusion: In our series, the MCF approach for VS provided excellent rates of tumor and facial nerve function, with durable serviceable HP.

Objectives:: Assess the utility of intraoperative transcranial facial motor-evoked potential (FMEP) monitoring in predicting and improving facial function after vestibular schwannoma (VS) resection., Study Design:: Retrospective chart review., Methods:: Data were obtained from 82 consecutive VS resections meeting inclusion criteria. Sixty-two cases were performed without FMEP and 20 with FMEP. Degradation of FMEP response was defined as a final-to-baseline amplitude ratio of 0.5 or less. House-Brackmann (HB) grade was assessed preoperatively, postoperatively, at follow-up assessments, and it was compared between pre- and post-FMEP cohorts. Positive predictive value (PPV) and negative predictive value (NPV), sensitivity, and specificity of FMEP degradation in predicting facial weakness were calculated., Results:: In the pre-FMEP group, at length of follow-up (LOF) ⩾9 months, 83.9% (52/62) of patients exhibited HB 1-2 outcome. In the post-FMEP cohort, 75.0% (15/20) exhibited HB 1-2 function at LOF ⩾9 months. There was no difference in rates of HB 1-2 outcomes between groups in the immediate postoperative period ( P = .35) or at long-term follow-up ( P = 1.0). With respect to predicting immediate postoperative facial function, FMEP demonstrated high specificity (88.9%) and moderate sensitivity (54.5%). The PPV and NPV for immediate postoperative facial function were 85.7% and 61.5%, respectively. With respect to long-term (⩾9 months LOF) facial function, intraoperative FMEP was moderately sensitive (71.4%) and highly specific (84.6%); PPV was moderate (71.4%), and NPV was high (84.6%)., Conclusions:: Intraoperative FMEP is highly specific and moderately sensitive in predicting postoperative facial function for patients undergoing VS resection, but its use may not be associated with improved facial nerve outcomes., Level of Evidence:: 4.

Objective: Postoperative headache is an undesirable consequence of retrosigmoid vestibular schwannoma (VS) removal. An ultrasonic bone aspirator (UBA) may reduce headache by minimizing subarachnoid bone dust dispersion. The feasibility of removing internal auditory canal (IAC) bone with a UBA is unknown. This study assessed volume and duration of IAC bone removal in clinical and laboratory settings., Study Design: (1) Retrospective review of radiologic data and intraoperative videos. (2) Cadaveric temporal bone model., Setting: (1) Tertiary care medical center. (2) Laboratory., Subjects Methods: We calculated the volume of IAC bone drilled during retrosigmoid VS removal using postoperative computed tomography scans. We then measured the time spent actively drilling IAC bone by analyzing operative videos. Finally, we measured bone ablation rates in a cadaveric temporal bone model using a drill and UBA., Results: The mean ± SD volume of IAC bone removed during surgery was 0.32 ± 0.17 mL (n = 9). The time spent actively removing IAC bone with a drill was only 10.4 ± 3.5 minutes, less than a third of the total IAC opening time of 34.2 ± 13.1 minutes (n = 5). On cadaveric specimens, the UBA removed bone at 0.21 ± 0.03 or 0.35 ± 0.07 µL/s at 15% or 50% power, respectively (n = 4). This extrapolates to 15.0 ± 3.0 to 25.0 ± 3.9 minutes to remove the same 0.32 mL from surgery., Conclusions: The volume and duration of IAC bone removal during retrosigmoid VS surgery are small. Using a UBA at low power instead of a drill would extend the length of surgery by 5 to 15 minutes, with the theoretical potential for reducing headache., (© American Academy of Otolaryngology—Head and Neck Surgery Foundation 2015.)

Objective: Postoperative headache is not uncommon after retrosigmoid vestibular schwannoma removal. Bone dust dispersed into the subarachnoid space during drilling may be responsible. If dispersion could be reduced, headache incidence might be decreased. An ultrasonic bone aspirator (UBA) containing an integrated suction at the tip may more effectively suction bone dust created during bone removal. The objective is to determine whether a UBA results in less bone dust dispersion than a standard otologic drill., Study Design: Cadaveric temporal bone quantitative model., Setting: Laboratory., Subjects and Methods: Temporal bone blocks were placed in a watertight enclosure. Under irrigation, bone was removed by use of either a drill or a UBA. The settings of the UBA were varied. The irrigant containing bone dust was microfiltered, and bone dust was weighed. Differences were compared across groups (n = 2-9 per group). Ablation times were also recorded (n = 3 per group)., Results: Only 3% (SD = 1.6%, n = 7) of the drilled bone mass was re-collected as bone dust with the UBA under optimized settings (power = 15%, suction = 100%, irrigation = 15 mL/min) compared with 81% (SD = 10%, n = 4) with the drill and external suction (P < .001). Increasing UBA power and reducing suction led to significantly more bone dust dispersal than with optimized settings. Varying irrigation did not have a significant effect. Bone ablation time was 1.4 times longer with the UBA at 50% power compared with the drill at maximum power., Conclusions: The UBA resulted in approximately 25 times less bone dust dispersion than the otologic drill at optimized settings., (© American Academy of Otolaryngology—Head and Neck Surgery Foundation 2015.)

Using light microscopy and immunoperoxidase methods (PAP), the presence of alpha-1-proteinase inhibitor (API) was studied in seventeen brain tumors and four normal brain samples. The brain tumors included four glioblastomas, five low-grade gliomas, two metastatic lung carcinomas, two acoustic schwannomas, and four meningiomas. Normal brain displayed a finely granular intracytoplasmic staining confined to neuronal cells. Glial cells were negative for API. Fifteen of the 17 brain tumors were positive for API. Only two of five low-grade gliomas were negative for API. Glioblastoma and metastatic tumors exhibited the strongest positivity followed by acoustic neuroma, meningioma, and low-grade glioma. All positive samples exhibited finely granular intracytoplasmic API, and 50% exhibited extracellular API positivity. Metastatic and glioblastoma tumors demonstrated prominent extracellular API staining. Our results support the concept of a local production of API by brain tumors.