Faculty Bibliography

OBJECTIVE: Is conscious sedation an effective, safe, and efficient anesthetic choice in patients undergoing select neurotologic and otologic procedures? STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: Six patients underwent eight neurotologic procedures including cerebrospinal fluid leak and encephalocele repair, and primary and revision cochlear implant surgery. Patients were deemed poor candidates for general anesthesia secondary to medical comorbidities. These were compared to 11 control patients who underwent same procedures under general anesthesia with intubation. INTERVENTION: Dexmedetomidine infusion was utilized as the primary agent for conscious sedation in this high-risk patient population because, unlike other commonly used sedatives, it preserves normal respirations while providing adequate analgesia. MAIN OUTCOME MEASURES: Preoperative Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity (P-POSSUM) scores were calculated for the study group. We measured total anesthesia, and perioperative and recovery times. Cost of anesthetic agents was considered and any adverse effects were noted. Patient satisfaction with the operative experience was assessed with telephone surveys. RESULTS: P-POSSUM scores were high for the study group. Postoperative anesthesia was shorter for the study patients undergoing conscious sedation. Difference in cost of anesthetic agents was negligible. The adverse effects were few and as expected for the type of procedure. Patients reported satisfaction and comfort with their operative experience. CONCLUSION: Select neurotologic and otologic procedures can be safely, effectively, and efficiently performed under conscious sedation with dexmedetomidine infusion as the primary anesthetic choice for patients who are deemed poor medical candidates for general endotracheal anesthesia.

OBJECTIVE: The preferential delayed enhancement of the perilymphatic space enables detection of the non-enhancing endolymphatic hydrops present in patients with Meniere's disease. The aim of this study was to evaluate the diagnostic utility of delayed postcontrast 3D FLAIR images and a color map of fused postcontrast FLAIR and constructive interference steady state (CISS) images in the identification of endolymphatic hydrops in patients with clinically diagnosed Meniere's disease. STUDY DESIGN: Case control, blinded study. SETTING: Tertiary referral center. PATIENTS: Ten patients with Meniere's disease and five volunteer controls. INTERVENTION: Diagnostic. MAIN OUTCOME MEASURE: Two neuroradiologists blinded to the clinical history independently evaluated for the presence of endolymphatic hydrops on the images of both inner ears for test and control subjects. Both the standard gray-scale FLAIR images and the fused color map images were independently reviewed. RESULTS: The gray-scale 3D FLAIR images demonstrated 68.2% sensitivity and 97.4% specificity, and the fused color map images demonstrated 85.0% sensitivity and 88.9% specificity in the identification of endolymphatic hydrops in Meniere's disease. There was significant correlation between the gray-scale 3D FLAIR images and fused color map images with the categorization of involvement (p = 0.002). Inter-evaluator reliability was excellent (kappa = 0.83 for gray-scale images, kappa = 0.81 for fused color map). CONCLUSION: Delayed 3D FLAIR and fused 3D FLAIR-CISS color map images of the inner ears after intravenous contrast administration are potentially useful diagnostic tools in the evaluation of patients with suspected Meniere's disease.

PURPOSE OF REVIEW: To summarize the recent medical literature related to the feasibility of hearing preservation after cochlear implantation and to identify variables that may influence hearing preservation in the implanted ear as well as the hearing perception outcomes. RECENT FINDINGS: The published data provide evidence that hearing preservation in the implanted ear yields significantly higher levels of speech recognition in complex listening environments than having just monaural acoustic hearing. There is ample evidence that hearing preservation is feasible and the reported rate is 50-89% in the low frequencies. This rate tends to be stable over time, except for a small percentage that diminishes around 3 months of follow-up. However, factors or variables which influence hearing preservation are yet unknown. Variables such as patient age, degree of residual hearing, insertion depth, insertion speed, duration of profound high frequency deafness and electrode design have been proposed. SUMMARY: Much attention has been focused on hearing preservation in the implanted ear. Thus, investigations into electrode array design, surgical technique and pharmacological management have been undertaken. Minimizing damage in the inner ear not only enhances the possibility for hearing preservation and better performance in complex listening scenarios but also conserves inner ear structures for future treatments.

Background Activation of the mammalian target of rapamycin (mTOR) signaling pathway is thought to be a key driver of tumor growth in Merlin (NF2)-deficient tumors. Everolimus is an oral inhibitor of mTOR complex 1 (mTORC1) with antitumor activity in a variety of cancers. Methods We conducted a single-institution, prospective, 2-stage, open-label phase II study to estimate the response rate to everolimus in neurofibromatosis type 2 (NF2) patients with progressive vestibular schwannoma (VS). Ten eligible patients were enrolled, including 2 pediatric patients. Everolimus was administered at a daily dose of 10 mg (adults) or 5 mg/m(2)/day (children <18 y) orally in continuous 28-day courses, for up to 12 courses. Response was assessed every 3 months with MRI, using 3-dimensional volumetric tumor analysis, and audiograms. Nine patients were evaluable for the primary response, defined as >/=15% decrease in VS volume. Hearing response was evaluable as a secondary endpoint in 8 patients. Results None of the 9 patients with evaluable disease experienced a clinical or MRI response. No objective imaging or hearing responses were observed in stage 1 of the trial, and the study was closed according to predefined stopping rules. Conclusion Everolimus is ineffective for the treatment of progressive VS in NF2 patients. We are currently conducting a pharmacokinetic/pharmacodynamic ("phase 0") study of everolimus in presurgical VS patients to elucidate the biological basis for apparent treatment resistance to mTORC1 inhibition in these tumors.

OBJECTIVES/HYPOTHESIS: In pediatric patients with congenital malformations of the inner ear, anomalies within the anatomy may facilitate unintentional insertion of the cochlear implant electrode into the internal auditory canal. Revision procedures for removal and replacement of cochlear implant electrodes following internal auditory canal insertion are fraught with potential danger, including the theoretical risk of injury to vasculature within the internal auditory canal, repeat insertion within the internal auditory canal, and cerebrospinal fluid leak. The objective of this presentation is to describe a technique for revision cochlear implantation following internal auditory canal insertion to minimize the potential associated risks. STUDY DESIGN: Case series. METHODS: A retrospective chart review was performed on all patients at a tertiary care facility who underwent revision cochlear implantation for internal auditory canal insertion between January 1999 and July 2011. RESULTS: A total of four patients referred from outside institutions have undergone revision cochlear implantation for internal auditory canal insertion. The records from these patients were reviewed. Electrodes were safely removed in all cases without injury to the anterior inferior cerebellar artery or its branches (i.e., labyrinthine artery). Complete insertion was accomplished on reimplantation. Neural response telemetry was performed in all cases, and responses were noted. Fluoroscopy was utilized to visualize electrode progression during insertion. A detailed description of the operative technique is provided. CONCLUSIONS: This case series describes a technique for revision cochlear implantation that appears to be safe and effective in preventing potential associated complications. Laryngoscope, 2013.

OBJECTIVE: To analyze the effects of residual hearing on postoperative speech performance in traditional cochlear implant (CI) patients implanted with a conventional electrode. STUDY DESIGN: Retrospective review. SETTING: Academic tertiary referral center. PATIENTS: A total of 129 adults implanted by a single surgeon at a tertiary care facility between June 2005 and November 2010 with measurable preoperative pure tone thresholds at any frequency were included. INTERVENTION: Cochlear implantation with a conventional electrode via an anterior inferior cochleostomy. MAIN OUTCOME MEASURE: Speech perception using monosyllabic word scores in quiet and sentences in quiet and noise in the electric (CI-only) condition of the implanted ear. Preservation of hearing was defined as complete for postoperative thresholds within 10 dB of preimplant values and partial if greater than 11 dB. Pure tone audiometry and speech perception testing were performed preoperatively and at regular intervals postoperatively, with the 1-year evaluation being the final outcome period. RESULTS: Preservation at any frequency or level was not a factor in speech perception outcome, although preservation was more common in low frequencies. Hearing preservation was correlated with younger age at implantation, but was not related to length of hearing loss, cause of deafness, device type, sex, preoperative speech performance, or low-frequency pure-tone average. CONCLUSION: Hearing can be preserved in traditional CI patients implanted with a conventional electrode. Although preservation of hearing may have implications for future technology, it is not currently correlated with speech performance in the CI-only condition.

OBJECTIVES/HYPOTHESIS: This pilot study details the use of a software tool that uses continuous impedance measurement during electrode insertion, with the eventual potential to assess and optimize electrode position and reduce insertional trauma. STUDY DESIGN: Software development and experimental study with human cadaveric cochleae and two live surgeries. METHODS: A prototype program to measure intracochlear electrode impedance and display it graphically in real time has been developed. The software was evaluated in human cadaveric temporal bones while simultaneously making real-time fluoroscopic recordings and in two live surgeries during intracochlear electrode insertion. RESULTS: Impedance changes were observed with various scalar positions, and values were consistent with those obtained using clinically available software. Using Contour Advance electrodes, impedance values increased after stylet removal, particularly when using the monopolar mode. CONCLUSIONS: Impedance values seem systematically affected by electrode position, with higher values being associated with proximity to the cochlear wall. The new software is capable of acquiring impedance measurements during electrode insertion, and these data may be useful to guide surgeons to achieve optimal and atraumatic electrode insertion, to guide robotic electrode insertion, and to provide insights about electrode position in the cochlea.