Hearing Preservation Microsurgery in Vestibular Schwannomas: Worth Attempting in “Larger” Tumors?

Abstract

Objectives/Hypothesis: To review hearing preservation after microsurgical resection of sporadic vestibular schwannomas according to tumor size.Study Design: Retrospective cohort. Methods: Baseline, intraoperative, and postoperative patient and tumor characteristics were retrospectively collected for a cohort who underwent hearing preservation microsurgery. Serviceable hearing was defined by a pure tone average ≤50 dB and word recognition score ≥50%.Results: A total of 243 patients had serviceable hearing preoperatively. Fifty (21%) tumors were confined to the internal auditory canal, and the median tumor size was 16.2 mm (interquartile range [IQR] 11.3-23.2) for tumors with cerebellopontine angle extension. Serviceable hearing was maintained in 64% of patients with tumors confined to the internal auditory canal, 28% with cerebellopontine angle extension <15 mm, and 9% with cerebellopontine angle extension ≥15 mm. On multivariable analysis, the odds ratios of acquiring nonserviceable hearing postoperatively for tumors extending <15 mm and ≥15 mm into the cerebellopontine angle were 5.75 (95% confidence interval [CI] 2.13-15.53; P < .001) and 22.11 (95% CI 7.04-69.42; P < .001), respectively, compared with intracanalicular tumors.Conclusions: The strongest predictor of hearing preservation with microsurgery after multivariable adjustment is tumor size. Approximately 10% of patients with tumors ≥15 mm of cerebellopontine angle extension will retain serviceable hearing after microsurgery. Furthermore, hearing preservation techniques offer cochlear nerve preservation and cochlear patency allowing for possible future cochlear implantation. An attempt at hearing preservation, including avoiding surgical approaches that necessarily sacrifice hearing, is worthwhile even in larger tumors if serviceable hearing is present preoperatively.

Skull Base Registries: A Roadmap

“…But it is usually also necessary to characterize the status of the lesion, including anatomical involvement, radiographic features, and disease-specific symptoms that have a significant impact on the anatomical approach, extent of maximal safe resection, and associated morbidities. 2,[21][22][23][24][25] Clearly, radiologic assessments will play an extremely important role in a successful skull base registry, but these are still lacking in some areas. In particular, our increasing ability to visualize cranial nerve involvement will hopefully lead to a consensus on classification systems for perineural spread of skull base lesions that have clinical or prognostic significance 26 .…”

Natural History of Serviceable Hearing During Active Surveillance of Nongrowing Sporadic Vestibular Schwannoma Supports Consideration of Initial Wait-and-Scan Management

“…The high rate of maintaining SH over time in small (<5 mm) intracanalicular tumors establishes a high standard for comparison to hearing preservation microsurgery or SRS. For small intracanalicular tumors, recent data on hearing preservation surgery performed at higher-volume centers indicate early postoperative preservation rates ranging from 57 to 91% (23)(24)(25)(26)(27)(28). Yet, even with successful hearing preservation microsurgery, a proportion of people exhibit subsequent hearing loss over time (29).…”

“…Foremost, the authors believe that management of small tumors should be highly individualized based on patient goals and priorities. In a motivated and informed patient, upfront microsurgery or radiosurgery is a reasonable consideration, with many experienced centers reporting microsurgery early postoperative hearing preservation rates of over 50% for small tumors (24)(25)(26)(27). Because tumor control and facial nerve function are achieved in most small VS regardless of single modality treatment, the primary considerations in this population are preserving residual functional hearing when present, quality of life, and cost-effectiveness (30,31).…”

American Cochlear Implant Alliance Task Force Guidelines for Clinical Assessment and Management of Adult Cochlear Implantation for Single-Sided Deafness

“…If there is a history of prior microsurgical tumor resection, then the operative note, postoperative imaging, and postoperative audiometric results will need to be reviewed to determine whether the cochlear nerve was preserved and the cochlea has not developed prohibitive ossification ( Hoffman et al 1992 ; Carlson et al 2012 ; Lloyd et al 2014 ; Deep et al 2019 ). Successful stimulation with a CI requires sufficient cochlear nerve health, and mere anatomical preservation of the cochlear nerve after tumor resection does not guarantee successful auditory pathway stimulation ( Wallerius et al 2022 ). Simultaneous translabyrinthine excision of vestibular schwannoma and cochlear implantation has also been described, with results ranging from no auditory detection to performance similar to conventional CI recipients ( Ahsan et al 2003 ; Lloyd et al 2014 ; Hassepass et al 2016 ; Sanna et al 2016 ; Rooth et al 2017 ; Choudhury et al 2019 ; Thompson et al 2019 ; Dahm et al 2020 ).…”