Endoscopic Endonasal Surgery of Skull Base Osteoradionecrosis with the Internal Carotid Artery Invaded: Clinical Characteristic and Surgical Strategy.

Objective: This study aims to summarize the clinical characteristics of skull base osteoradionecrosis (ORN) with the internal carotid artery (ICA) involvement and to distill the key surgical techniques that can enhance the protective measures for ICA.

Methods: We conducted a retrospective, observational study over a six-year period from February 2017 to May 2023. We included patients who were diagnosed with osteoradionecrosis with invasion of the internal carotid artery and collected their demographic information, pathology results, complication rates, ect. The goal was the alleviated rate after the surgery and the anatomic consideration during the surgery. We compared the verbal rating score (VRS) of headache pre- and post-operation by the Wilcoxon rank-sum test.

Results: A retrospective analysis was conducted on 19 patients diagnosed with ORN, with a mean age of 53.73 yr (range, 32-68 yr). Among them, 17 patients (89.47%) were nasopharyngeal carcinoma (NPC), 1 patient (5.23%) was squamous cell carcinoma of the sphenoid sinus, and 1 patient (5.23%) had adenoid cystic carcinoma. After the surgery, 1 fatality occurred within 2 months, which was attributed to a severe parapharyngeal space infection.1 patient succumbed to ICA rupture two days post-operation. Additionally, 1 patient experienced ORN recurrence 2 years after the initial surgery. The mean follow-up period for the study was 37.47 mo (range 2 -77 mo). The alleviation rate was 89.4%. The results revealed a significant decrease in VRS after the surgery (Z=-3.921, P=0.000). Finally, we summarized clinical evidences of ICA involvement, such as the formation of pseudoaneurysm.

Conclusion: A four-quadrant division of SBORN as a standardized and systematic approach is meaningful to guide surgical intervention for osteoradionecrosis. There are relevant clinical and imaging evidences that can predict the rupture of ICA.