2025 Proffered Presentations
S357: HEARING LOSS AFTER MICROVASCULAR DECOMPRESSION SURGERY PERFORMED WITH THE RETRO-MASTOID SUBOCCIPITAL APPROACH: A SINGLE-CENTER STUDY, ANALYSIS OF 682 CASES
HyunSeok Lee, MD1; Kwan Park, MD, PhD1; Sang-Ku Park1; Dong-Han Lee, MD2; 1Konkuk University Medical Center, Department of Neurosurgery; 2Konkuk University Medical Center, Department of Otorhinolaryngology
Hearing loss is one of the most serious complications of microvascular decompression (MVD) surgery. In our institution, we analyzed the prognosis of hearing in 682 cases of MVD surgery with the retromastoid suboccipital craniotomy (RMSOC). From September 2020 to March 2024, 683 patients who were being followed up after MVD surgery by a single surgeon.
Of the 682 patients, 616 were hemifacial spasm (HFS), 65 were trigeminal neuralgia (TN), and 1 was glossopharyngeal neuralgia (GPN). In all patients, RMSOC was performed in the park-bench position, and craniotomy was performed to the visible sigmoid sinus and to the margin of the transverse sinus. In order to prevent cerebellar swelling after craniotomy, CSF was drained from the lateral medullary cistern to decompress the cerebellum. Pre- and postoperative audiometry examination was performed in all patients, and real time brain stem auditory evoked potential (BAEP) monitoring was performed by an experienced neurophysiologist throughout the surgery.
There were no life-threatening complications, including surgery-related death. Of 682 patients, in postoperative pure tone audiometry (PTA) and speech audiometry (SA) examinations, 6 patients had complete hearing loss, 1 had worsened to non-serviceable hearing. All of whom had hemifacial spasm. This was 1.0% of all MVD patients and 1.1% among patients with hemifacial spasm. Partial hearing loss, a decrease in hearing of 20db or more from preoperative, occurred in 37 patients, 35 with HFS and 2 with TN. Of the 2 TN patients, one recovered about a month after surgery, and the other was developed a delayed low-frequency hearing loss about one month later. Of 35 patients who developed partial hearing loss after MVD surgery for HFS, 5 patients developed conductive hearing loss and improved. Of the other 30, 8 had a high frequency hearing loss, 14 had a low frequency hearing loss, and the remaining 8 had a full range partial hearing loss.
We report on the risk factors and incidence of this hearing loss complication by analyzing the patterns of neurovascular compression, other surgical findings such as indentation grade, BAEP change pattern, etc.