KHẢO SÁT TRÌNH TRẠNG DÂY THẦN KINH MẶT CHE KHUẤT ĐẾ XƯƠNG BÀN ĐẠP TRÊN CT SCAN ỨNG DỤNG TRONG PHẪU THUẬT ĐIỀU TRỊ XỐP XƠ TAI

Abstract

Background: Otosclerosis is a disorder resulting from abnormal bone metabolism in the otic capsule, leading to stapes fixation and subsequent hearing loss. The primary treatment is stapes replacement surgery. One of the major complications is facial nerve palsy due to aberrant anatomical positioning of the facial nerve, which can be identified preoperatively through temporal bone CT scanning. Objective: To investigate the anatomical variations of the facial nerve (FN) overhanging the stapes footplate on CT scans and its clinical relevance in otosclerosis surgery. Materials and Methods: A cross-sectional study was conducted on 70 patients  who underwent stapes surgery for otosclerosis at the Ho Chi Minh City Ear–Nose–Throat Hospital. Preoperative CT scans were evaluated to assess the relationship between the FN and the stapes footplate. Results: Among 70 operated ears, 17 cases (24,3%) showed FN overhanging partially or completely across the stapes footplate. The distances from FN to the anterior crus (dAC), stapes (dS), and posterior crus (dPC) were significantly shorter in the overhanging group compared with the non-overhanging group (p < 0,05). On logistic regression analysis, dPC was identified as the strongest predictor of FN overhang, with an AUC of 0.834, sensitivity of 76,5%, and specificity of 83,0%. No cases of postoperative facial palsy were recorded. Conclusion: FN overhanging the stapes footplate is a critical anatomical factor in otosclerosis surgery. The distance dPC can serve as a reliable preoperative radiological marker on CT scans, assisting surgeons in surgical planning and minimizing the risk of complications.