Incidence and Risk Factors for Free Flap Compromise in Head and Neck Reconstruction: A Meta-Analysis.

Abstract

Microvascular free flap reconstruction is the gold standard for head and neck defects, but flap compromise remains a primary cause of reconstructive failure. This study aims to evaluate the pooled incidence of flap compromise and total flap failure, and to identify risk factors to optimize perioperative management. A systematic search was conducted across PubMed, MEDLINE, Embase, the Cochrane Library, and Web of Science for studies published up to September 1, 2025. This meta-analysis followed the PRISMA guidelines. Two independent reviewers screened the literature, extracted data, and assessed study quality using the Newcastle-Ottawa Scale (NOS). Random-effects models were used to calculate pooled incidences and odds ratios (ORs) with 95% confidence intervals (CIs). Forty-seven studies involving 30,002 free flaps were included. The pooled incidence of flap compromise was 8.2% (95% CI: 6.6%-9.9%), with a complete failure rate of 3.9% (95% CI: 3.2%-4.7%). Flap compromise was significantly associated with prior radiotherapy (OR = 3.98). Other significant non-modifiable factors included diabetes (OR = 2.20), advanced age (OR = 1.35), and high comorbidity scores (OR = 1.68). Importantly, several modifiable factors were identified as critical drivers, including fluid overload (OR = 2.57), prolonged operative time (OR = 2.14), low serum albumin (OR = 2.06), low BMI (OR = 1.75), and low hemoglobin (OR = 1.34). Free flap compromise remains a clinically significant complication. These findings support integrating modifiable physiological markers into preoperative risk stratification and implementing targeted, multidisciplinary optimization strategies to improve flap outcomes.