Hearing recovery after surgical resection of non-vestibular schwannoma cerebellopontine angle tumors

Cerebellopontine Angle Meningiomas: A Multi-Institutional Cohort Study

BACKGROUND AND OBJECTIVES

Cerebellopontine angle (CPA) meningiomas present challenges given their proximity to neurovascular structures. Postoperative complications and persistent symptoms can debilitate patients, and our ability to predict recovery course remains variable. Here, we examine the presentation, management, and outcomes of patients with CPA meningiomas.

METHODS

We retrospectively reviewed CPA meningiomas resected at Mass General Brigham, using descriptive statistics and logistic regression to identify predictors of progression or recurrence.

RESULTS

In total, 95 patients were identified (median age 59.1 years, 82.1% female) who presented most commonly with hearing loss (49.5%), ataxia (42.1%), and headaches (29.5%). The retrosigmoid (78.9%) or transmastoid retrosigmoid (17.9%) approaches were most frequently used for resection, with gross total resection (GTR) achieved in 62.1% of patients: Simpson grade 1 (32.6%), grade 2 (17.9%), and grade 3 (11.6%). Smaller tumor size (t = 3.17, P = .002) is associated with GTR. For tumors with intracanalicular invasion, drilling the internal auditory canal (IAC) was also associated with GTR (χ2 = 21.8, P < .001). Among cases with invasion, GTR was achieved in 88.5% of cases when the IAC was drilled vs 11.8% of cases when the IAC was not drilled. The cranial nerve VII/VIII complex was frequently inferior (45.6%) or superior (19.1%) to the meningioma. Postoperative hearing loss was stable (38.7%) or improved (54.8%) in most of patients at the final clinical follow-up (median: 39.4 months). 25.3% of patients had progression/recurrence, with some difference between World Health Organization grade 1 (median: 3.0 years, IQR: 2.9 years) and World Health Organization grade 2 (median: 1.6 years, IQR: 2.8 years) tumors. After multivariate adjustment, Simpson grade I (P = .02), Simpson grade II (P = .01), or being of older age (P = .003) were associated with lower odds of progression/recurrence.

CONCLUSION

GTR remains critical to achieve optimal symptom control and reduce progression/recurrence rates for CPA meningiomas. Drilling the IAC is an important predictor of GTR in tumors with intracanalicular invasion.

Predictors of hearing functional outcome following surgery for cerebellopontine angle meningioma

OBJECTIVE

Cerebellopontine angle (CPA) meningiomas can affect hearing function and require expeditious treatment to prevent permanent hearing loss. The authors sought to determine the factors associated with functional hearing outcome in CPA meningioma patients treated with surgery and/or radiation therapy in the form of either stereotactic radiosurgery or stereotactic radiation therapy.

METHODS

Consecutive patients with CPA meningiomas who had presented at our hospital from 2008 to 2018 were identified through retrospective chart review. Hearing function (as defined by pure tone average (PTA) and speech discrimination score (SDS) on Audiogram) was assessed before and after surgery for CPA meningioma. Audiograms with PTA > 50 dB and SDS < 69% were defined as poor hearing functional outcome. Multivariable Cox Proportional Hazards Regression Model was used to assess the associations between pre-operative hearing functional assessment and post-operative hearing functional outcomes.

RESULTS

The study cohort included 31 patients (80.6% females, with a mean age of 61.3 ± 15.2 years) with a median clinical follow-up of 5 months (range: 1 week-98 months). The mean pre-operative PTA and SDS were 23.8 ± 11.2 dB and 64.4 ± 22.2% respectively. At the last visit, there was significant hearing recovery, with an improvement of 29.7 ± 18.0 dB (p < 0.001) and 87.6 ± 17.8% (p < 0.001) in PTA and SDS respectively. After adjusting for age, gender, tumor volume, location, and tumor classification, Multivariable Cox Proportional Hazards Regression Model was conducted which revealed that patients undergoing surgery through retro sigmoid approach [Hazards Ratio (HR): 32.1, 95% Confidence Interval (CI): 2.11-491.0, p = 0.01] and gross total resection (GTR) (HR: 2.99, 95% CI: 1.09-9.32, p = 0.05) had significantly higher risk of poor hearing functional outcome compared to petrosal approach and near/subtotal resection. Moreover, patients with poor preoperative hearing had 85% higher chance of poor hearing functional outcome postoperatively (HR: 0.15, 95%CI: 0.03-0.59, p = 0.007).

CONCLUSION

Postoperative improvement in hearing is a reasonable expectation following surgery for CPA meningioma. Preoperative hearing, surgical approach and extent of surgical resection are predictive factors of postoperative hearing function outcome and can therefore aid in identification of patients at higher risk of hearing loss.