A hearing preservation technique for acoustic neuroma resection via retrosigmoid sinus approach

Abstract Background: Acoustic neuroma, also known as vestibular schwannoma, is a non-cancerous tumor that accounts for up to 90% of all cerebellopontine angle (CPA) tumors. The treatment for acoustic neuroma typically involves surgical removal of the tumor. The most common surgical approach is translabyrinthine surgery, which involves resection of the tumor in the inner auditory canal (IAC) and in the cerebellopontine horn area. Adequate excision of the IAC is essential for complete tumor removal from this area. However, this type of surgery can result in injuries to the inner ear, leading to hearing loss and balance problems. Advances in surgical techniques for IAC resection have improved canal exposure without causing significant damage to the inner ear. Objective: Preoperative imaging, such as three-dimensional (3D) high-resolution computed Tomography (HRCT), can be used to calculate the optimal resection angles for IAC excision. These images provide detailed information on the location and size of the tumor, as well as the surrounding structures in the ear. Methods: This study included 256 patients diagnosed with unilateral acoustic neuroma who underwent HRCT scans before and after surgery. Images were acquired and analyzed using the Syngo 2008G workstation. IAC was then assessed and surgery was planned based on the acquired HRCT images. Results: The optimal angle of grinding for the labyrinth was 42.3°, which allowed for IAC resection in 76.3% patients and total tumor resection in 94.1% patients as well as ensured the integrity of the labyrinth during the surgical procedure. Conclusion: We hope that our method of calculation will serve as a useful guide for practicing surgeons when performing this complex surgery. We anticipate that with the application of endoscope-assisted neurosurgical technique and electrophysiological monitoring, the preservation of facial and vestibulocochlear nerve functions in acoustic neuroma surgery will be further improved.