2025 Proffered Presentations
S172: PREDICTING RISK FACTORS FOR FACIAL NERVE SACRIFICE DURING TEMPORAL BONE RESECTION FOR LATERAL SKULL BASE MALIGNANCIES
Roberto M Soriano, MD; Alejandra Rodas, MD; Michael Baddour, MD; David Chou, MD; C. Arturo Solares, MD; Emory University
Objective: Lateral skull base malignancies (LSBM) that involve the temporal bone, are often of cutaneous or salivary origin, frequently require complex surgical intervention to achieve oncologic control. When the temporal bone is involved, a temporal bone resection (TBR) is usually performed as part of a composite resection to ensure negative margins. However, due to the proximity of these tumors to the facial nerve (FN), resection carries a significant risk of FN sacrifice. While sacrifice is not always necessary, predicting when it will be required remains challenging because of the varied tumor characteristics, such as multi-spatial involvement and the need for extensive resections. Until now, no studies have specifically analyzed the factors that influence the likelihood of FN sacrifice in patients undergoing lateral temporal bone resections (LTBR). This study aims to address this gap by identifying characteristics that increase the risk of FN sacrifice in these patients.
Methods: A retrospective chart review was conducted, approved by the Institutional Review Board (IRB), at Emory University for patients who underwent LTBR for LSBM from 8/2016 to 7/2024. The study included 96 patients, predominantly male, with a mean age of 67. Various factors were examined, including extent of resection, perineural invasion (PNI), tumor origin, preoperative House-Brackmann (HB) score to indicate FN function, amongst others. Univariate analysis, using a chi-squared test, was performed to assess these variables' impact on FN sacrifice.
Results: Sixty-nine patients (72%) required FN sacrifice during LTBR. Most of these patients (77%) had a preoperative HB score of II or higher. Tumors were most commonly of cutaneous or salivary origin. In addition to LTBR, resections commonly included parotidectomy (97%), infratemporal fossa (ITF) resection (87%), jugular foramen (JF) dissection (51%), zygomatic arch resection (49%), mandibulectomy (52%) and auriculectomy (39%). Perineural invasion was found in a majority of cases. By contrast, 28% of patients did not require FN sacrifice, and most of these patients had a preoperative HB score of I or better, reflecting. These patients more often had cutaneous tumors, with fewer requiring extensive resections into critical anatomical areas. Preliminary analysis identified several key factors associated with a higher likelihood of FN sacrifice during LTBR. Preoperative HB grade was significantly correlated with nerve sacrifice, with a score of II or greater being a strong predictor of nerve sacrifice. Extensive resections, particularly those extending into the ITF, mandible, and JF, were also significantly associated with an increased risk of FN sacrifice, further demonstrating the complexity and multi-spatial nature of these tumors. While salivary-origin tumors showed a higher rate of nerve sacrifice, this correlation did not reach statistical significance.
Summary: This study is the first of its kind to comprehensively analyze the factors contributing to FN sacrifice in LTBR for lateral skull base malignancies. The findings provide valuable insights into the preoperative predictors of nerve sacrifice, highlighting the importance of preoperative FN function and the extent of tumor invasion. These insights can significantly improve surgical planning, patient counseling, and postoperative management, including determination of need of FN reanimation procedures at the time of surgery for facial rehabilitation.