Hearing preservation in acoustic neuroma surgery

Introduction: Acoustic Neuroma's (AN) are benign tumors arising from the vestibular nerves, usually within the internal auditory canal, where hearing loss is the most common symptom. Although many authors have written about hearing presrvation in acoustic tumor surgery, there is little uniform opinion in the literature as to what truly defines preserved hearing. Objective: To determine the results of hearing preservation surgery in our AN database and which patients should be operated for hearing preservation. Study Design: Retrospective. Setting: University hospital practice. Patients: One hundred and ninety patients with AN's operated between 1986 and 1998, age ranging between 23 and 80 years; 38 patients underwent middle fossa (MF) surgery; 57 patients underwent suboccipital (SO) approach for AN. Intervention: Diagnosis of AN and surgery for preservation of hearing. Outcome measures: Preoperative and postoperative (up to 9 months after surgery) average air conduction thresholds (1,2, and 4K), and speech discrimination scores (SDS) were noted. Results: The outcome of hearing results was better with the MF approach as compared to the SO approach (1. Mean of the difference between postoperative and preoperative hearing thresholds, MF: 25.7 dB±31.44; SO: 47.88 dB±34.37; p=0.01, 2. Mean of the difference between preoperative and postoperative SDS values, MF: -32.73% + 41.12; SO: -65.04% ±40.43 p=0.01). Tumor size did not significantly influence hearing results. Conclusions: Hearing results are better with the MF approach as compared to the SO approach. Tumor size does not significantly impact hearing results.