Acoustic neuroma surgery for preservation of hearing: technique and experience in the Chinese PLA General Hospital

Conclusions: Good hearing preservation can be achieved during acoustic neuroma surgery assisted by real-time dynamic auditory monitoring and ear endoscopic techniques. Preservation of the arachnoid and its blood supply are important for hearing preservation, and injury to the internal auditory artery is the most important cause of hearing loss. Objective: To explore techniques to preserve hearing during acoustic neuroma resection. Methods: This was a retrospective case review in a hospital setting. From July 2003 to July 2007, intraoperative auditory monitoring using auditory brainstem response (ABR) and electrocochleography (EcochG) was conducted in 18 of 138 patients undergoing surgery for acoustic neuroma who had preoperative hearing. The retrosigmoid approach was used for 16 complete resections and 2 patients underwent partial resections. Assisted endoscopic surgery was conducted for 10 ears. The main outcome measure was preservation of hearing, assessed using the classification method of the American Institute of Otolaryngology-Head and Neck Surgery. Results: Hearing was preserved in 11 of the 18 patients (61.1%): 2 of 5 patients whose tumors were larger than 20 mm (40%), and 9 of 13 patients with smaller tumors (69.2%). Among the 10 cases of ear endoscope-assisted surgery, hearing was preserved in 8 (80%). Intraoperative monitoring revealed that the waveform was influenced when the posterior labium of the internal acoustic meatus was ground and drilled, or when traction or electrocoagulation was performed near the opening of the internal acoustic meatus, especially when the internal auditory artery was clamped, the tumor in the internal acoustic meatus was treated, and the arachnoid vessels in the inner-most layer of the tumor surface were clamped or electrocoagulated.