Endoscopic Endonasal Reconstruction of Anterior Skull Base Defects: What Factors Really Affect the Outcomes?

Abstract

Objective: Endoscopic endonasal surgery has evolved in recent decades, requiring comparable advances in reconstructive techniques. This study aimed to retrospectively review outcomes of endoscopic anterior skull base reconstruction and to analyze factors associated with failures.

Methods: Data from patients who underwent endoscopic endonasal anterior skull base reconstruction in a single institution between 1998 and 2017 were collected. Patients were stratified according to selected risk factors: sex; age; previous surgery; disease treated (cerebrospinal fluid leaks, benign tumors, malignant tumors); single or multiple defects; defect dimension (<1 cm², 1-2 cm², 2-6 cm², >6 cm²) and site (olfactory cleft, ethmoidal roof, planum sphenoidalis, posterior wall of frontal sinus); reconstruction technique (overlay graft, multilayer grafts, pedicled flap) and materials used; postoperative radiotherapy; and year of surgery. Statistical significance was assessed using Fisher exact test. Univariate logistic regression was implemented to analyze the association between risk factors and failures.

Results: Inclusion criteria were met by 513 cases with median follow-up of 96 months (range, 12-257 months). Success rate for initial repair was 95% (487/513), with 100% success rate for secondary closure after revision surgery. Failures were not significantly related to sex (P = 0.54), reconstruction technique (P = 0.28), location of defect (P = 0.65), dimension (P = 0.69), disease (P = 0.83), or postoperative radiotherapy (P = 0.83). Year of surgery, considered as a continuous variable, was associated with a statistically significant reduction of failures (odds ratio = 0.89, P = 0.005).

Conclusions: Endoscopic surgery is safe and effective for anterior skull base reconstruction. Refinements in surgical technique and increasing experience have contributed to improved success rates.

Keywords: Anterior skull base; Cerebrospinal fluid leak; Endoscopic surgery; Expanded endonasal approaches; Nasoseptal flap; Sinonasal tumor.