2025 Poster Presentations
P270: ENDOSCOPIC REPAIR OF SKULL BASE DEFECTS USING FREE TISSUE TRANSFER: A CASE SERIES
Eric Nisenbaum, MD, MSc; Joseph Lee, MD; Ricardo Carrau, MD; Kyle VanKoevering, MD; The Ohio State University Wexner Medical Center Department of Otolaryngology - Head and Neck Surgery
Background: Open approaches to the ventral skull base have been increasingly replaced by endoscopic endonasal approaches due to lower associated morbidity. Expanded endoscopic techniques provide access to the vast majority of the ventral skull base, allowing for safe treatment of pathology that would have previously required an open approach. Likewise, these techniques can allow for the endoscopic reconstruction of skull base defects not previously amenable to minimally invasive repair. The use of free tissue transfer for the repair of large or otherwise challenging ventral skull base defects is well described in the literature, but traditionally requires access through an open approach such as a bifrontal or orbitozygomatic craniotomy. In this case series, we describe 11 patients who underwent ventral skull base repair using free flaps which were inset through an endoscopic approach and a retropharyngeal or trans-maxillary access, minimizing the morbidity associated with open craniotomy.
Case Series: A retrospective chart review was performed of 11 consecutive patients with ventral skull base defects with cerebrospinal fluid (CSF) leak who presented to a tertiary care academic medical center between 2016 and 2024 and underwent endoscopic surgical repair with a free flap. 3 patients had osteoradionecrosis of the clivus, 5 had osteoradionecrosis of the anterior cranial fossa, and 3 had planned surgical interventions resulting in CSF leaks with a lack of other regional options for repair. In each case, a muscle only anterolateral thigh free flap was harvested and used for the repair. The flaps were delivered to the skull base through either a retropharyngeal (3 cases) or transmaxillary (8 cases) corridor, positioned using endoscopic instrumentation, and secured into place using absorbable nasal packing. 10 of 11 patients had successful long term repair of their CSF leak, with 1 patient experiencing a delayed leak recurrence 2 years after surgery. There were no flap failures.
Discussion: This case series – to our knowledge the largest to date - presents the repair of challenging anterior skull base defects in 11 patients using free flaps delivered and inset via a minimally invasive endoscopic approach. This technique allows surgeons to leverage the advantages of free tissue transfer such as large tissue volume, customization, and the ability to bring healthy, vascularized tissue into a radiated field while avoiding the morbidity associated with open approaches to the skull base. Further studies are needed to continue to optimize both delivery corridors and inset technique.