Endoscopic-Assisted Free Flap Reconstruction of Skull Base Defects Resulting from Osteoradionecrosis

Background: Osteoradionecrosis (ORN) of the skull base represents one of the most formidable challenges in head and neck surgery due to the intricate anatomy, limited surgical corridors, and the proximity of critical neurovascular structures. While free tissue transfer has become the standard of care in mandibular and maxillary ORN, its application to skull base defects is a relatively new endeavor and requires careful consideration of approach. Here we describe a small series of patients in which we utilize a novel 2-corridor approach for ORN reconstruction of the skull base via free-flap transfer. Methods: A combined endoscopic endonasal approach (EEA) with bi-nostril access and wide sphenoidotomy was utilized for skull base recipient site preparation, with particular attention paid to meticulous debridement to healthy tissue. Access was achieved via a medial maxillectomy was performed via anterior mucosal and bony osteotomies, including transection of the nasolacrimal duct and removal of the medial maxillary wall. A sublabial Caldwell-Luc transmaxillary corridor was then created, providing a direct tunnel for flap transposition. Following flap harvest, cervical exposure of facial vessels enabled pedicle passage through a buccal tunnel into the nasal cavity. Free flap inset covered the skull base defect, followed by microvascular anastomosis. Results: In both patients undergoing this technique for ORN skull base reconstruction, excellent exposure of the skull base defect was obtained through the bi-nostril access and Caldwell-Luc antrostomy. Both patients underwent an uncomplicated post-operative course in the hospital prior to discharge (5 days). 6 month follow up for both patients revealed healthy vascularized tissue with no evidence of ongoing ORN or CSF leak. Conclusion: The integration of EEA with a Caldwell-Luc transmaxillary corridor for free flap reconstruction of skull base ORN serves as a viable technique to provide direct access to the skull base with enhanced surgical maneuverability and potential reduced the pedicle distance of the flap, especially in cases with extensive involvement of the anterior skull base. Publication History Article published online: 27 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany