Intracranial supramaximal facial nerve stimulation: a murine model.

PURPOSE: Supramaximal facial nerve stimulation is an applied current sufficient to evoke a maximal electromyographic response of facial musculature. It is used during cerebellopontine angle surgery for prognostication of postoperative nerve function. We utilized a rat model to examine safe parameters for intracranial electrical stimulation. MATERIALS AND METHODS: Intracranial facial nerve stimulation with electromyographic monitoring of 14 rats was performed. Supramaximal current level was determined and 50 additional pulses of supramaximal (4 rats), 3 times supramaximal (4), 10 times supramaximal (3), or zero (3) current were applied. To monitor progression of facial nerve injury, video recordings of vibrissae movements and eye closure were captured at 1, 3 and 28 days after surgery; animals were sacrificed on day 28, when nerve morphometry was performed. RESULTS: One rat in the supramaximal stimulation group (of 4), and one rat in the 10 times supramaximal stimulation group (of 3) demonstrated persistent impairment of facial nerve function as evidenced by decreased amplitude of vibrissae sweeping and eye closure impairment. The remainder of rats in all experimental groups demonstrated symmetric and normal facial nerve function at all time points. CONCLUSIONS: A novel animal model for supramaximal stimulation of the rat intracranial facial nerve is described. A small proportion of animals demonstrated functional evidence of nerve injury postoperatively. Function was preserved in some animals after stimulation with current order of magnitude higher than supramaximal levels. Further study with this model is necessary to definitively isolate the effects of surgical trauma from those of supramaximal electrical stimulation.

Sudden Sensorineural Hearing Loss in Patient Incidental to Treatment With Hyaluronic Acid Filler.

Hyaluronic acid fillers comprise a major component of aesthetic practice with few serious adverse effects. Hearing loss has not been previously associated with hyaluronic acid filler. The authors describe a case in which a patient developed sudden sensorineural hearing loss 1 day after filler injection into the nasolabial folds. Audiogram showed moderately severe sensorineural loss, and MRI revealed no abnormalities. Despite transtympanic steroid injections and hyperbaric oxygen therapy, the hearing loss persists at the time of writing. Although no causal relationships can be drawn from this case alone, this case serves to reinforce the importance of continued vigilance for future occurrences to minimize the potential risk of this serious adverse event.

Quantification of Fat Graft Retention in the Translabyrinthine Approach Using Magnetic Resonance Imaging Volumetric Analysis.

OBJECTIVE: To characterize the viability and volume of autologous free fat grafts over time, determine clinical/patient factors that may affect free fat graft survival and assess the clinical impact of free fat graft survival on patient outcomes in the translabyrinthine approach for lateral skull base tumor resection. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary neurotologic referral center. PATIENTS: Forty-two adult patients who underwent translabyrinthine craniotomy for resection of a lateral skull base tumor with the mastoid defect filled by autologous abdominal fat graft and subsequently underwent more than one postoperative magnetic resonance imaging (MRI) scans of the brain. INTERVENTIONS: Mastoid obliteration with abdominal fat after craniotomy, postoperative MRI. MAIN OUTCOME MEASURES: Rate of fat graft volume loss, fraction retention of original fat graft volume, initial fat graft volume, time to steady-state fat graft retention, rate of postoperative cerebrospinal fluid (CSF) leak, and/or pseudomeningocele formation. RESULTS: Patients were followed postoperatively with MRI for a mean of 31.6 months with a mean of 3.2 postoperative MRIs per patient. Initial graft size was a mean of 18.7 cm3 with a steady-state fat graft retention of 35.5%. Steady-state graft retention (<5% loss per year) was achieved at a mean of 24.96 months postoperatively. No significant association was found in multivariate regression analysis of clinical factors impact on fat graft retention and CSF leak/pseudomeningocele formation. CONCLUSIONS: In the use of autologous abdominal free fat graft for filling mastoid defects after translabyrinthine craniotomy, there is a logarithmic decline in fat graft volume over time, reaching steady state in 2 years. Rates of CSF leak or pseudomeningocele formation were not significantly affected by initial volume of the fat graft, rate of fat graft resorption, nor the fraction of original fat graft volume at steady state. In addition, no analyzed clinical factors significantly influenced fat graft retention over time.

Rationale for the Development of a Novel Clinical Grading Scale for Postoperative Facial Nerve Function: Results of a Multidisciplinary International Working Group.

OBJECTIVE: The objective of the current study was to present the results of an international working group survey identifying perceived limitations of existing facial nerve grading scales to inform the development of a novel grading scale for assessing early postoperative facial paralysis that incorporates regional scoring and is anchored in recovery prognosis and risk of associated complications. STUDY DESIGN: Survey. SETTING: A working group of 48 multidisciplinary clinicians with expertise in skull base, cerebellopontine angle, temporal bone, or parotid gland surgery. RESULTS: House-Brackmann grade is the most widely used system to assess facial nerve function among working group members (81%), although more than half (54%) agreed that the system they currently use does not adequately estimate the risk of associated complications, such as corneal injury, and confidence in interrater and intrarater reliability is generally low. Simplicity was ranked as the most important attribute of a novel postoperative facial nerve grading system to increase the likelihood of adoption, followed by reliability and accuracy. There was widespread consensus (91%) that the eye is the most critical facial region to focus on in the early postoperative setting. CONCLUSIONS: Members were invited to submit proposed grading systems in alignment with the objectives of the working group for subsequent validation. From these data, we plan to develop a simple, clinically anchored, and reproducible staging system with regional scoring for assessing early postoperative facial nerve function after surgery of the skull base, cerebellopontine angle, temporal bone, or parotid gland.

Ultrasound-Guided Placement of Percutaneous Abutments for Bone Conduction Hearing Devices.

OBJECTIVE: To introduce a minimally invasive and image-guided technique for staged placement of a percutaneous abutment after osseointegrated implantation. PATIENTS: Adults undergoing temporal bone resection at two academic medical centers. INTERVENTIONS: Ultrasound-guided percutaneous installation of a bone conduction hearing device abutment. All patients had lateral temporal bone resection with osseointegrated implantation. Abutment placement followed as a planned staged procedure 3 to 6 months later depending on the use of radiotherapy. MAIN OUTCOME MEASURES: Ability to use a bone conduction hearing device and occurrence of skin reactions or wound complications. RESULTS: Twelve patients successfully underwent abutment installation through a 5 mm skin biopsy punch incision, nine of which had minimal to no skin reaction surrounding the abutment. Two patients developed Holgers grade 1 skin reaction (redness with slight swelling). One patient experienced an osseointegration failure 152 days after abutment placement. CONCLUSIONS: Ultrasound is a widely available imaging modality that can be used to precisely localize subcutaneous osseointegrated implants, allowing for minimally invasive percutaneous placement of an abutment under local or general anesthesia.

Predictive Effect of Bone Conduction Pattern on Hearing Outcomes of Stapes Surgery.

OBJECTIVE: Examine the effect of preoperative bone conduction pattern on outcomes of stapedotomy/stapedectomy. STUDY DESIGN: Retrospective case series. SETTING: Tertiary-care academic medical center. PATIENTS: Patients who underwent stapedotomy or stapedectomy from 2013 to 2019. INTERVENTIONS: Primary small-fenestra stapedotomy or partial stapedectomy. MAIN OUTCOME MEASURES: Association between preoperative bone conduction patterns and hearing after stapes surgery. RESULTS: Complete audiometric data were available for 137 patients who had surgery. The mean preoperative air-bone gap (ABG) was 26.8 dBHL. The ABG was closed to less than 20 and 10 dBHL in 88.7 and 65.2% of patients, respectively. A notch at 2000 Hz was present in 32.1% of operated ears and was rarely found at other frequencies. There was no statistically significant association between the presence of a notch and hearing outcomes. The slope of the bone conduction line had no association with hearing outcomes, though an increased bone conduction PTA compared with the contralateral ear was associated with ABG closure less than 10 dBHL and overclosure (odds ratio: 2.14, p = 0.027 and odds ratio: 2.20, p = 0.04). CONCLUSION: In properly selected otosclerosis patients, depressions in bone conduction other than near 2000 Hz are rare and hearing outcomes are generally favorable regardless of the preoperative bone conduction pattern. Despite the association with otosclerosis, the presence of a notch at 2000 Hz is not associated with better hearing outcomes with surgery.

The Feasibility of Magnetic Resonance Imaging for the Differentiation of Cerebrospinal Fluid Leak From Middle Ear Effusion: A Quantitative Analysis.

OBJECTIVE: Assess quantitatively whether magnetic resonance imaging (MRI) signal intensity can be used to distinguish cerebrospinal fluid (CSF) leaks in the temporal bone from middle ear effusions. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: Forty-nine patients, 18 with middle ear effusions (MEE), 30 with CSF leaks, and 1 with an MEE on one side and a CSF leak on the other, were evaluated in the study. Primary inclusion criteria for CSF leak patients were operative management of CSF leak with confirmatory diagnosis in follow-up. Primary inclusion criteria for MEE patients were electronic medical record documentation of an effusion with subsequent resolution on follow-up. For all patients, inclusion criteria included MRI imaging with 3D-T2 weighted sequences (3DT2) and fluid-attenuated inversion recovery (FLAIR) sequences performed within 1 year of diagnosis code entry. INTERVENTION: Computational analysis of signal intensity of fluid collections in MRI imaging. MAIN OUTCOME MEASURES: Sensitivity and specificity of 3DT2 and FLAIR signal intensity in the detection of CSF leak. RESULTS: For 3DT2 sequences with a chosen normalized signal intensity threshold (CSF leak if ≥ 0.5), sensitivity was 100% (95% CI: 86.3-100) and specificity was 83.3% (95% CI: 51.6-97.9). For FLAIR sequences with a threshold of 1.0 (CSF leak if < 1.0), sensitivity was 77.4% (95% CI: 58.9-90.4) and specificity was 85.7% (95% CI: 63.6-97.0). For a combined test in which a fluid collection was considered CSF if both 3DT2 ≥ 0.5 and FLAIR < 1.0, sensitivity was 76% (95% CI: 54.9-90.6) and specificity was 100% (95% CI: 73.5-100).

Middle Cranial Fossa Approach to Vestibular Schwannoma Resection in the Older Patient Population.

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.

Determining treatment choices after the cochlear implant evaluation process.

OBJECTIVES: Determine the proportion of patients starting the cochlear implant evaluation (CIE) process proceeding to cochlear implantation.Determine which patient factors are associated with undergoing cochlear implantation. METHODS: Retrospective case series of all patients scheduled for a CIE within a tertiary academic neurotology practice between January 1, 2014 and April 30, 2016. Management pathways of patients undergoing CIE were examined. RESULTS: Two hundred thirty-seven adult patients were scheduled for CIE during the study period. Two hundred twenty-six patients started the evaluation process, and 203 patients completed full evaluation. Of patients that completed CIE, 166/203 (82%) met criteria for implantation and 37/203 (18%) did not meet criteria. Fifty-nine patients out of 166 patients (36%) meeting criteria did not receive implants and 107/166 (64%) underwent implantation, yielding an overall implantation rate of 47% (107/226) among patients scheduled for CIE. Common reasons for deferring CI among candidates included failure to show up for preoperative appointment (24%), choosing hearing aids as an alternative (22%), patient refusal (21%) and insurance issues (17%). Overall, CIE led to a new adjunctive hearing device (CI or hearing aid) in 113 (113/203, 56%) cases. CONCLUSION: Fifty-six (113/203) percent of patients who underwent CIE at an academic medical center underwent CI surgery or received an adjunctive hearing device, but 36% (59/166) of candidates did not receive a CI. Patients who forewent CI despite meeting candidacy criteria did so due to cost/insurance issues, or due to preference for auditory amplification rather than CI. LEVEL OF EVIDENCE: 4.

Real-World Compliance With Follow-up in 2,554 Cochlear Implant Recipients: An Analysis of the HERMES Database.

BACKGROUND: Traditional paradigms of care recommend close audiology follow-up and regular speech perception outcomes assessment indefinitely for cochlear implant (CI) recipients after device activation. However, there is scant published data on actual compliance with this paradigm in clinical practice. METHODS: A multi-center cochlear implant database was queried to identify follow-up rates after cochlear implantation. Follow-up rates where speech perception outcomes assessment occurred at 1-, 3-, 6-, 12-, 18-, and 24-months post-activation were determined by tabulating observed follow-up divided by expected follow-up (O/E ratio) expressed as a percentage. To determine all-cause audiology follow-up rates (with or without testing speech perception outcomes assessment), the database patients from two participating centers (one private practice and one academic center) were similarly analyzed using electronic health record (EHR) data to calculate O/E rates where audiology follow-up occurred for any reason. RESULTS: O/E follow-up rates where speech perception outcomes assessment occurred was 42, 40, 31, 29, 5, and 22% for 1-, 3-, 6-, 12-, 18-, and 24-months post-activation, respectively (n = 2,554). All-cause audiology follow-up rates (with or without speech perception outcomes assessment) using EHR-confirmed data from two individual centers were 97, 94, 81, 66, 41, and 35% at 1-, 3-, 6-, 12-, 18-, and 24-months post-activation visits, respectively (n = 118). CONCLUSIONS: Compliance with audiology follow-up and speech perception outcomes assessment is generally low and decreases significantly as time post-activation increases. Future paradigms of care for CI should be designed recognizing the significant attrition that occurs with CI follow-up.

The Potential for Preserved Cochleovestibular Function in the Setting of Prolonged Pneumolabyrinth.

OBJECTIVE: To discuss the natural history and management of pneumolabyrinth, with particular attention to illustrative cases where hearing improved after a fluid-filled vestibule was restored. PATIENTS: Adults at two academic medical centers with documented pneumolabyrinth on computed tomography (CT) imaging. INTERVENTION: Middle ear surgery or observation. MAIN OUTCOME MEASURES: Cochlear and vestibular symptoms are reported. Inner ear function was documented with audiometry and vestibular testing. Resolution of pneumolabyrinth was documented on imaging for a subset of patients. RESULTS: All patients presented with severe hearing loss following temporal bone fracture (three cases), penetrating trauma (one case), or stapedectomy (three cases). The radiographic finding was typically seen when imaging was obtained in the first few days after the injury. In two cases, vestibular symptoms resolved and partial recovery of hearing was seen despite a relatively long time interval between the inciting event and repair. CONCLUSION: Management of pneumolabyrinth is individualized based on the mechanism of injury, severity of symptoms, and timing of the imaging study. In most cases, the barrier between the middle ear and inner ear is expected to heal with rapid resolution of pneumolabyrinth. Late repair is demonstrated to result in favorable recovery in selected cases. The presence of air in the vestibule cannot be assumed to be indicative of irreversible inner ear damage.

Hemifacial Spasm as a Rare Clinical Presentation of Idiopathic Intracranial Hypertension: Case Report and Literature Review.

OBJECTIVES: To report a rare case of idiopathic intracranial hypertension (IIH) presenting with hemifacial spasm (HFS) and review the current literature. METHODS: Case report and literature review. The patient's medical record was reviewed for demographic and clinical data. For literature review, all case reports or other publications published in English literature were identified using PUBMED. RESULTS: A 43-year-old obese female presented with a 2-year history of left HFS.Electroencephalography and head computed tomography were unremarkable. Magnetic resonance imaging demonstrated bilateral anterior inferior cerebellar artery vascular loops involving the internal auditory canals as well as IIH-associated findings. A lumbar puncture was performed and revealed an elevated opening pressure of 26 cm H20 cerebrospinal fluid. Acetazolamide treatment was then initiated, resulting in complete resolution of the HFS. CONCLUSION: HFS may be a rare presenting manifestation of IIH, and treatment of IIH may result in improvement of HFS symptoms. This is the first report of IIH presenting with HFS in the absence of headache or visual change. As a result, this is the first report of HFS as a presenting manifestation of IIH in Otolaryngology literature.

Visual Speech Recognition: Improving Speech Perception in Noise through Artificial Intelligence.

OBJECTIVES: To compare speech perception (SP) in noise for normal-hearing (NH) individuals and individuals with hearing loss (IWHL) and to demonstrate improvements in SP with use of a visual speech recognition program (VSRP). STUDY DESIGN: Single-institution prospective study. SETTING: Tertiary referral center. SUBJECTS AND METHODS: Eleven NH and 9 IWHL participants in a sound-isolated booth facing a speaker through a window. In non-VSRP conditions, SP was evaluated on 40 Bamford-Kowal-Bench speech-in-noise test (BKB-SIN) sentences presented by the speaker at 50 A-weighted decibels (dBA) with multiperson babble noise presented from 50 to 75 dBA. SP was defined as the percentage of words correctly identified. In VSRP conditions, an infrared camera was used to track 35 points around the speaker's lips during speech in real time. Lip movement data were translated into speech-text via an in-house developed neural network-based VSRP. SP was evaluated similarly in the non-VSRP condition on 42 BKB-SIN sentences, with the addition of the VSRP output presented on a screen to the listener. RESULTS: In high-noise conditions (70-75 dBA) without VSRP, NH listeners achieved significantly higher speech perception than IWHL listeners (38.7% vs 25.0%, P = .02). NH listeners were significantly more accurate with VSRP than without VSRP (75.5% vs 38.7%, P < .0001), as were IWHL listeners (70.4% vs 25.0% P < .0001). With VSRP, no significant difference in SP was observed between NH and IWHL listeners (75.5% vs 70.4%, P = .15). CONCLUSIONS: The VSRP significantly increased speech perception in high-noise conditions for NH and IWHL participants and eliminated the difference in SP accuracy between NH and IWHL listeners.

Early Experience With Telemedicine in Patients Undergoing Otologic/Neurotologic Procedures.

OBJECTIVE: Compare outcomes for patients who were seen via telemedicine visits after otology/neurotology surgical procedures with those who were seen in traditional office visits. STUDY DESIGN: Retrospective case review. SETTING: Tertiary care academic medical center. PATIENTS: Inclusion criteria were patients who underwent otologic/neurotologic surgery and were seen in at least one telemedicine visit for postoperative care. INTERVENTION (S): Telemedicine visit for postoperative care. MAIN OUTCOME MEASURE (S): Comparison of the number of patient calls, unplanned visits, and delayed complications between telemedicine patients and controls matched for age, procedure, and American Society of Anesthesiologists (ASA) status. RESULTS: Eighteen patients were seen in telemedicine visits postoperatively after the following otologic/neurotologic surgical procedures: cochlear implant surgery (10), vestibular schwannoma resection (4), combined middle fossa and transmastoid cerebrospinal fluid (CSF) leak repair (2), middle fossa repair of superior canal dehiscence (1), and stapedectomy (1). All telehealth visits were for the second postoperative visit. The mean number of patient calls after surgery was 2.3 for the telemedicine group and 1.9 for matched controls which was not a statistically significant difference (p = 0.466). Both groups each had two patients who went to the emergency room, with one in each group being admitted. There was one delayed complication in the control group. CONCLUSION: Our preliminary experience suggests telemedicine may be used safely in caring for patients after otologic/neurotologic surgery, though it may be associated with more patient phone calls. Further study and experience, including assessing patient satisfaction, will clarify the future role of telemedicine in otology and neurotology.

Is Longer Surgery More Dangerous? Operative Duration Not Associated With Complications After Vestibular Schwannoma Resection.

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.

Laboratory testing and imaging in the evaluation of cranial cerebrospinal fluid leaks and encephaloceles.

PURPOSE OF REVIEW: To summarize the current evidence on the diagnostic evaluation of cranial cerebrospinal fluid (CSF) leaks and encephaloceles, including laboratory testing and imaging studies. RECENT FINDINGS: The most sensitive and specific laboratory tests for CSF leak diagnosis are beta-2-transferrin and beta trace protein assays, the former more commonly used because of availability. Imaging studies used for localization of the leak site include high resolution computed tomography (HRCT) and magnetic resonance cisternography (MRC), often used in combination. Intrathecal contrast administration is reserved for complex cases with prior equivocal test results or for patients with multiple skull base defects to localize the leak site. SUMMARY: Diagnosis of CSF leaks and encephaloceles is aimed at both confirming the leak and localizing the leak site. Future advancements in testing techniques may shorten the diagnostic process, limit the need for invasive testing, and improve the safety of such testing in indicated cases.

Obesity Is Not Associated With Postoperative Complications After Vestibular Schwannoma Surgery in a Large Single Institution Series.

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.

Cerebrospinal Fluid Leak Rate after Vestibular Schwannoma Surgery via Middle Cranial Fossa Approach.

Objective Evaluate the cerebrospinal fluid (CSF) leak rate after the middle cranial fossa (MCF) approach to vestibular schwannoma (VS) resection. Design Retrospective case series. Setting Quaternary referral academic center. Participants Of 161 patients undergoing the MCF approach for a variety of skull base pathologies, 66 patients underwent this approach for VS resection between 2007 and 2017. Main Outcome Measure Postoperative CSF leak rate. Results There were two instances of postoperative CSF leak (3.0%). Age, gender, and BMI were not significantly associated with CSF leak. In the two cases with CSF leakage, tumors were isolated to the internal auditory canal (IAC) and both underwent gross total resection. Both CSF leaks were successfully treated with lumbar drain diversion. For the 64 cases that did not have a CSF leak, 51 were isolated to the IAC, 1 was located only in the cerebellopontine angle (CPA), and 12 were located in both the IAC and CPA. 62 patients underwent gross total resection and 2 underwent near-total resection. Mean maximal tumor diameter in the CSF leak group was 4.5 mm (range: 3-6 mm) versus 10.2 mm (range: 3-19 mm) in patients with no CSF leak ( p = 0.03). Conclusions The MCF approach for VS resection is a valuable technique that allows for hearing preservation and total tumor resection and can be performed with a low CSF leakage rate. This rate of CSF leak is less than the reported rates in the literature in regard to both translabyrinthine and retrosigmoid approaches.

Utility of Magnetic Resonance Imaging in Differentiating Cerebrospinal Fluid Leak from Middle Ear Effusion.

OBJECTIVE: To demonstrate the clinical utility, sensitivity, and specificity of standard magnetic resonance imaging (MRI) sequences in differentiating temporal bone cerebrospinal fluid leaks from all other middle ear effusions. STUDY DESIGN: Retrospective imaging review. SETTING: Academic medical center. SUBJECTS: Patients with cerebrospinal fluid leaks or other middle ear effusions who also underwent MRI. METHODS: Patients were assigned to cerebrospinal fluid leak and other effusion cohorts based on clinical course, findings at surgery/myringotomy, and beta-2 transferrin fluid analysis. Reviewers blinded to the clinical outcome examined T1-weighted, T2-weighted, diffusion-weighted, fluid-attenuated inversion recovery (FLAIR), and 3-dimensional (3D) acquired T2-weighted MRI sequences. For each sequence, fluid imaged in the temporal bone was graded as either similar or dissimilar in signal intensity to cerebrospinal fluid in the adjacent subarachnoid space. Signal similarity was interpreted as being diagnostic of a leak. Test characteristics in predicting the presence of a leak were calculated for each series. RESULTS: Eighty patients met criteria (41 leaks, 39 other effusions). The 3D T2 series was 76% sensitive and 100% specific in diagnosing a leak, and FLAIR was 44% sensitive and 100% specific. The T1-weighted (73% sensitive, 69% specific), T2-weighted (98% sensitive, 5.1% specific), and diffusion-weighted (63% sensitive, 66% specific) series were less useful. CONCLUSIONS: MRI, with attention to 3D T2 and FLAIR series, is a noninvasive and highly specific test for diagnosing cerebrospinal fluid leak in the setting of an indeterminate middle ear effusion.

Impact of Motor-Evoked Potential Monitoring on Facial Nerve Outcomes after Vestibular Schwannoma Resection.

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.