Preoperative Radiographic Predictors of Hearing Preservation After Retrosigmoid Resection of Vestibular Schwannomas

Abstract

Objective To identify preoperative radiographic predictors of hearing preservation (HP) after retrosigmoid resection of vestibular schwannomas (VSs). Study Design Retrospective case series with chart review. Setting Tertiary skull base referral center. Methods Adult patients with VSs <3 cm and word recognition scores (WRSs) ≥50% who underwent retrosigmoid resection and attempted HP between February 2008 and December 2018 were identified. Pure tone average (PTA), WRS, and magnetic resonance imaging radiographic data, including tumor diameter and dimensional extension relative to the internal auditory canal (IAC), were examined. Results A total of 151 patients were included. The average tumor size was 13.8 mm (range, 3-28). Hearing was preserved in 41.7% (n = 63). HP rates were higher for intracanalicular tumors than tumors with cerebellopontine angle (CPA) components (57.6% vs 29.4%, P = .03). On multivariate analysis, maximal tumor diameter (odds ratio [OR], 0.892; P < .001) and preoperative PTA (OR, 0.974; P = .026) predicted HP, while mediolateral tumor diameter predicted postoperative PTA (OR, 1.21; P = .005) and WRS (OR, –1.89; P < .001). For tumors extending into the CPA, younger age (OR, 0.913; P = .012), better preoperative PTA (OR, 0.935; P = .049), smaller posterior tumor extension (OR, 0.862; P = .001), and smaller caudal extension relative to the IAC (OR, 0.844; P = .001) all predicted HP. Conclusion Rates of HP are highest in patients with small intracanalicular VSs and good preoperative hearing. For tumors extending into the CPA, greater posterior and caudal tumor extension relative to the IAC may portend worse hearing outcomes.

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

“…11,12 The present study revisits this paradigm in a consecutive series of 243 patients with serviceable hearing who underwent microsurgical resection of VS-most of whom had cisternal growth and 44% with ≥15 mm of CPA extension-representing a relatively large cohort when compared to prior studies. 11,[13][14][15][16] Serviceable hearing was preserved in 66 (27%) patients, with an inverse relationship between tumor size and likelihood of successful hearing preservation (P < .001). Based on size category, serviceable hearing was preserved at most recent evaluation in 64% of patients with tumors confined to the IAC, 28% in CPA tumors measuring <15 mm, and 9% in tumors ≥15 mm in the cistern.…”

“…The only other characteristic that was statistically significantly associated with retaining serviceable hearing postoperatively was the presence of a fundal fluid cap (odds ratio 0.42; P = .04). While patients with preoperative hearing class B were more likely to have postoperative nonserviceable hearing compared to those with preoperative hearing class A, as demonstrated in recent literature, 15,16 this association did not achieve statistical significance after multivariable adjustment for tumor size (odds ratio 1.74; P = .16).…”

“…Acknowledging this, some surgeons favor pursuing a TL approach after certain size thresholds are reached to reduce the reported morbidity that may be incurred with a RS approach, forgoing attempts at hearing preservation in the process 11,12 . The present study revisits this paradigm in a consecutive series of 243 patients with serviceable hearing who underwent microsurgical resection of VS—most of whom had cisternal growth and 44% with ≥15 mm of CPA extension—representing a relatively large cohort when compared to prior studies 11,13–16 . Serviceable hearing was preserved in 66 (27%) patients, with an inverse relationship between tumor size and likelihood of successful hearing preservation ( P < .001).…”

“…[6][7][8][9][10] Tumor size has been identified as a primary predictor of successful hearing preservation following microsurgical resection. [11][12][13][14][15][16] Based on prior data suggesting a low likelihood of functional hearing preservation with medium-tolarge sized VS, some have recommended forgoing attempts at hearing preservation once a VS reaches a certain size threshold (e.g., 15 mm cerebellopontine angle [CPA] dimension), instead preferring a translabyrinthine (TL) approach to reduce potential morbidity. 11,12 However, recent data suggest that complication rates and long-term global and domain-specific quality of life measures are not significantly different among surgical approaches, 17,18 including the oft-cited postcraniotomy headache.…”

“…Tumor size has been identified as a primary predictor of successful hearing preservation following microsurgical resection 11–16 . Based on prior data suggesting a low likelihood of functional hearing preservation with medium‐to‐large sized VS, some have recommended forgoing attempts at hearing preservation once a VS reaches a certain size threshold (e.g., 15 mm cerebellopontine angle [CPA] dimension), instead preferring a translabyrinthine (TL) approach to reduce potential morbidity 11,12 .…”