Evaluation of a Slim Modiolar Electrode Array: A Temporal Bone Study.

HYPOTHESIS: Evaluation of the Slim Modiolar (SM) electrode in temporal bones (TB) will elucidate the electrode's insertion outcomes. BACKGROUND: The SM electrode was designed for atraumatic insertion into the scala tympani, for ideal perimodiolar positioning and with a smaller caliber to minimize interference with cochlear biological processes. METHODS: The SM electrode was inserted into TBs via a cochleostomy. First, the axial force of insertion was measured. Next, TBs were inserted under fluoroscopy to study insertion dynamics, followed by histologic evaluation of electrode placement and cochlear trauma. A subset of TBs were inserted with the Contour Advance (CA) electrode for comparison. RESULTS: Sixteen of 22 insertions performed to measure the axial force of insertion had flat or near zero insertion force profiles. Six insertions had increased insertion forces, which were attributed to improper sheath depth before electrode insertion. Under real-time fluoroscopy, 23 of 25 TBs had uneventful insertion and good perimodiolar placement. There was 1 scala vestibuli insertion due to suboptimal cochleostomy position and 1 tip roll over related to premature electrode deployment. When compared with the CA electrode, 14 of 15 insertions with the SM electrode resulted in a more perimodiolar electrode position. No evidence of trauma was found in histologic evaluation of the 24 TBs with scala tympani insertions. CONCLUSION: TB evaluation revealed that the SM electrode exerts minimal insertion forces on cochlear structures, produces no histologic evidence of trauma, and reliably assumes the perimodiolar position. Nonstandard cochleostomy location, improper sheath insertion depth, or premature deployment of the electrode may lead to suboptimal outcomes.

Spontaneous Volumetric Tumor Regression During Wait-and-Scan Management of 952 Sporadic Vestibular Schwannomas.

OBJECTIVE: Spontaneous tumor shrinkage during wait-and-scan management of sporadic vestibular schwannoma is generally considered an uncommon phenomenon. However, most data informing this understanding stem from single-slice linear tumor measurements taken in the axial imaging plane. The objective of the current work was to characterize the regression capacity of sporadic vestibular schwannomas using volumetric tumor measurements. STUDY DESIGN: Retrospective cohort study using slice-by-slice, three-dimensional volumetric tumor measurements. SETTING: Three tertiary referral centers. PATIENTS: Patients with sporadic vestibular schwannoma. INTERVENTIONS: Wait-and-scan. MAIN OUTCOME MEASURES: Regression-free survival rates with regression defined as a decrease of at least 20% of the tumor volume. RESULTS: Among 952 patients undergoing a total of 3,505 magnetic resonance imaging studies during observation, 123 experienced volumetric tumor regression after diagnosis at a median of 1.2 years (interquartile range, 0.6-2.9 yr). Volumetric regression-free survival rates (95% confidence interval; number still at risk) at 1, 3, and 5 years after diagnosis were 94% (92-95%; 662), 86% (83-89%; 275), and 78% (73-82%; 132), respectively. Among 405 patients who demonstrated an initial period of tumor growth but continued wait-and-scan management, 48 experienced volumetric regression at a median of 1.2 years (interquartile range, 0.8-2.6 yr) after initial growth. Volumetric regression-free survival rates at 1, 3, and 5 years after initial growth were 94% (92-97%; 260), 84% (79-89%; 99), and 75% (67-83%; 43), respectively. Ultimately, only 82 of the 952 patients studied showed exclusively volumetric tumor regression (i.e., without any periods of tumor growth) by the time of last follow-up. CONCLUSION: Spontaneous volumetric tumor shrinkage during wait-and-scan management occurs more frequently than suggested by previous studies using linear tumor measurements and can even occur after previous episodes of documented tumor growth. These data further highlight the dynamic nature of vestibular schwannoma growth. To this end, the application of natural history data to patient management requires a nuanced approach that parallels the complex tumor behavior of vestibular schwannoma.

Speech perception benefits of sequential bilateral cochlear implantation in children and adults: a retrospective analysis.

OBJECTIVE: To examine speech perception outcomes and determine the impact of length of deafness and time between implants on performance in the sequentially bilateral implanted population. STUDY DESIGN: Retrospective review. SETTING: Tertiary academic referral center. PATIENTS: Forty-three children (age, <18 yr) and 22 adults underwent sequential bilateral implantation with at least 6 months between surgeries. The mean age at the time of the second implant in children was 7.83 years, and mean time between implants was 5.16 years. Five children received the first side implant (C1) below 12 months of age; 16, at 12 to 23 months; 9, between the ages of 24 and 35 months; and 11, at 36 to 59 months; 2 were implanted above the age of 5 years. In adults, mean age at second implant was 46.6 years, and mean time between implants was 5.6 years. INTERVENTION: Sequential implantation with 6 months or more between implantations. MAIN OUTCOME MEASURES: Speech perception tests were performed preoperatively before the second implantation and at 3 months postoperatively. RESULTS: Results revealed significant improvement in the second implanted ear and in the bilateral condition, despite time between implantations or length of deafness; however, age of first-side implantation was a contributing factor to second ear outcome in the pediatric population. CONCLUSION: Sequential bilateral implantation leads to significantly better speech understanding. On average, patients improved, despite length of deafness, time between implants, or age at implantation.