Faculty Bibliography

Although the preponderance of cerebellopontine angle lesions are schwannomas, focused attention to patient clinical history, imaging studies, and tissue biopsies when indicated will aid in detection of less common lesions that might otherwise be misdiagnosed. This is most critical for pathologies that dictate different management paradigms be undertaken.

OBJECTIVES/HYPOTHESIS: Trauma to intracochlear structures during cochlear implant insertion is associated with poorer hearing outcomes. One way surgeons can influence insertion trauma is by choosing the surgical approach. We seek to compare cochleostomy (CO), peri-round window (PRW), and round window (RW) approaches using a fresh frozen temporal bone model. STUDY DESIGN: Experiments using fresh frozen temporal bones. METHODS: Cochlear implant insertions using the three aforementioned approaches were performed on 15 fresh frozen human temporal bones using a Cochlear 422 electrode. Insertions were evaluated by examining fluoroscopic recordings of histologic sections. RESULTS: Five cochlear implant insertions were performed using each of the three aforementioned approaches. Fluoroscopic examination revealed that none of the CO or PRW insertions contacted the modiolus during insertion, whereas three of five RW insertions did. RW insertions were less linear during insertion when compared to CO and PRW insertions (P < .05). CO insertions had significantly larger angular depth of insertion (487 degrees ) when compared to PRW (413 degrees ) and RW (375 degrees ) (P < .05). Histologic examination revealed one RW insertion resulted in osseous spiral lamina fracture, whereas the remaining insertions had no evidence of trauma. In the damaged specimen, the inserted electrode was observed to rest in the scala vestibuli, whereas the remaining electrodes rested in the scala tympani. CONCLUSIONS: Due to variability in RW anatomy, a CO or PRW window surgical approach appears to minimize the risk for insertion trauma. However, with favorable anatomy, a Cochlear 422 electrode can be inserted with any of the three approaches. LEVEL OF EVIDENCE: NA Laryngoscope, 125:966-971, 2015.

Motion sickness can be a limiting factor for sea and air missions. We report the experience of a Pararescue (PJ) team on a Pacific Ocean rescue mission in which motion sickness was prevalent. Cinnarizine, an antagonist of H1-histamine receptors, was used to treat affected PJs. We also report findings of a survey of PJs regarding motion sickness. A family of four on a disabled sailboat 900 miles off the coast of Mexico sent out a distress call because their 1-year-old daughter became severely ill with fever and diarrhea. Four PJs were deployed on a C-130, performed a free-fall parachute insertion into the ocean, and boarded the sailboat. All four PJs experienced onset of motion sickness at some point during the early part of the mission and symptoms persisted through the first 24 hours. Three PJs experienced ongoing nausea, vomiting, dizziness, and sensory imbalances. The captain of the sailboat offered the three sick PJs approximately 18mg of cinnarizine two or three times a day with relief of symptoms and improvement on operational effectiveness. A new, anonymous, voluntary survey of Air National Guard PJs and combat rescue officers revealed that 78.4% of Operators have experienced motion sickness at sea. We discuss the current theories on motion sickness, the effect of motion sickness on operational effectiveness, and research on treatment of motion sickness, including the medication cinnarizine.

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.