Healing Following Endoscopic Reconstruction of the Anterior Skull Base in Patients With Sinonasal Malignancies

Background: Healing dynamics after anterior skull base (ASB) reconstruction following transnasal endoscopic surgery (TES) for sinonasal malignancies remain poorly characterized. This study aimed to describe the postoperative healing process, quantify time to healing, identify factors influencing healing, and assess radiologic evolution over time. Methods: This multicenter retrospective study included adult patients undergoing TES with craniectomy and ASB reconstruction for sinonasal malignancies between 2016 and 2024. Serial endoscopic examinations were reviewed using a novel stage-based classification system. Postoperative contrast-enhanced magnetic resonance imaging (MRI) was analyzed to evaluate reconstruction layers, enhancement patterns, thickness changes, and brain sagging. Cumulative incidence analysis, multistate modeling, and uni- and multivariable analyses were performed to identify factors associated with healing. Results: A total of 173 patients were included. Complete endoscopic healing was achieved in 15.9% of patients at 6 months, 69.9% at 12 months, and 94.4% at 24 months. Local pedicled flap reconstruction was associated with faster healing, with complete healing achieved in 89.4% of patients at 12 months compared with 60.7% in graft-based reconstructions (p < 0.001). Adjuvant radiotherapy (RT), particularly intensity-modulated proton therapy, was independently associated with delayed healing. MRI showed progressive reduction in reconstruction thickness, decreased visibility of adipose tissue and the outer graft layer, and increased brain sagging over time. RT was associated with greater remodeling changes, whereas flap-based reconstruction appeared to mitigate these effects. Conclusions: Healing after ASB reconstruction following TES is a prolonged and dynamic process influenced mainly by reconstruction technique and adjuvant RT. Local vascularized flaps promote faster and more stable healing and may be particularly advantageous in patients requiring postoperative RT.