Outcomes of Free Flap Soft Tissue Reconstruction for Skull Base Defects: A Systematic Review and Meta-Analysis

Skull base defects due to a variety of pathologies compromise structural integrity, function, and cosmesis, leading to detrimental effects for patients. A thorough understanding of the surgical approach, resection, and reconstruction is critical to ensure success. This study focuses on free flap reconstruction in skull base defects through the use of various muscle donor sites: anterolateral thigh, rectus abdominis, latissimus dorsi, and radial forearm. Each donor site has distinct strengths and limitations, and must be examined on a case-by-case basis. A systematic search was performed in the PubMed, Scopus, and Web of Science databases. A single-arm meta-analysis of proportions was performed to calculate pooled effect sizes. The inverse variance method was used to combine effect sizes from individual studies and calculate the 95% confidence interval (CI). Twenty-four studies comprising 392 patients were included. The pooled total flap failure rate was 0.0% (95% CI: 0.0-1.0), while partial flap failure occurred in 1.0% (95% CI: 0.0-4.0). Complications included cerebrospinal fluid leak (3.0%, 95% CI: 0.0-6.0), hematoma (1.0%, 95% CI: 0.0-4.0), and venous congestion/thrombosis (2.0%, 95% CI: 0.0-6.0). No significant differences were found between donor sites, and heterogeneity across outcomes was uniformly low. Free flap soft tissue reconstruction for skull base defects is associated with high success rates and low complication rates across donor sites. All major donor sites demonstrated comparable outcomes, supporting their versatility and reliability. Donor site selection should be individualized based on defect requirements and surgeon expertise.