PubMed abstract / permitted excerpt

OBJECTIVE: 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. DATA SOURCES: A systematic search was conducted across PubMed, MEDLINE, Embase, the Cochrane Library, and Web of Science for studies published up to September 1, 2025. REVIEW METHODS: 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). RESULTS: 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). CONCLUSION: 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.