Kutz, Walter

Objective To assess Advanced Bionics (AB) HiRes Ultra and Ultra 3D initial version (V1) cochlear implant electrode failures over time at four large cochlear implant programs. Study Design Retrospective cohort. Setting Four tertiary referral centers. Patients Patients receiving AB HiRes Ultra and Ultra 3D initial version (V1) devices as of December 31, 2022. Main Outcome Measures Failure rate, revision surgery, speech recognition scores. Results Over a span of 7 years, 205 (42.6%) of 483 implanted V1 devices have failed. Device failure rate varied across institutions from 32 to 67%. Of the 205 detected failures, 163 (79%) have undergone revision surgery, with 94% of revisions being performed with Advanced Bionics devices. Average time from implantation to diagnosis of device failure was 2.7 ± 1.2 years. Most patients (89.8%) with available testing were matched or exceeded their best prefailure speech performance after implant revision. After revision, patients had an average CNC score improvement of 24.7 percentage points over their most recent pre-revision scores and demonstrated average datalogging of 12.7 ± 4.1 h/d at most recent evaluation. Conclusions Comparison of patients across multiple high-volume implant centers confirms the presence of ongoing device failures. There is variability across institutions in the rate of revision surgery once a patient is diagnosed with a V1 device failure, as well as in the rate of device failure detection. Inter-institutional variability in failure rates may be explained by the variation in the routine use of electrical field imaging. Reimplantation with a new device typically results in a return to prefailure peak performance. Professional Practice Gap & Educational Need To our knowledge, a comparison of AB HiRes (V1) device failures across multiple institutions has not been conducted. Learning Objective To identify device failure rate across multiple institutions with different testing protocols. Desired Result Providers will have an improved understanding of the trajectory of device failures for HiRes (V1) devices over time. Level of Evidence Level IV—Historical cohort or case-controlled studies. Indicate IRB or IACUC IRB #230017; IRB #22-000183; IRB #STU-032018-085; IRB #H-49479.

Objective To describe outcomes of patients with sporadic vestibular schwannoma (VS) who underwent repeat stereotactic radiosurgery (SRS) after primary SRS failure. Study Design Multi-institutional historical cohort study. Setting Five tertiary care referral centers. Patients Adults ≥18 years old with sporadic VS. Intervention Primary and repeat treatment with SRS. Main Outcome Measure Microsurgery-free survival after repeat SRS. Results Across institutions, 32 patients underwent repeat SRS after primary SRS. Most patients (74%) had tumors with cerebellopontine angle extension at primary SRS (median size, 13.5 mm [interquartile range, 7.5–18.8] mm). After primary SRS, patients underwent repeat SRS at a median of 4.8 years (interquartile range, 3.2–5.7 yr). For treatment modality, 30 (94%) patients received gamma knife for primary treatment and 31 (97%) patients received gamma knife as their repeat treatment. Median tumor volume increased from 0.970 cm3 at primary SRS to 2.200 cm3 at repeat SRS. Facial nerve function worsened in two patients after primary SRS and in two patients after repeat SRS. There were no instances of intracranial complications after repeat SRS. Microsurgery-free survival rates (95% confidence interval; number still at risk) at 1, 3, and 5 years after repeat SRS were 97% (90–100%, 24), 84% (71–100%, 13), and 68% (48–96%, 6), respectively. There was one occurrence of malignancy diagnosed after repeat radiosurgery. Conclusion Overall, repeat SRS for sporadic VS has comparable risk profile, but lower rates of tumor control, compared with primary SRS.