Free Flap Outcome in Irradiated Recipient Sites: A Systematic Review and Meta-analysis.

[UNLABELLED] The impact of previous radiotherapy on free flap outcome is still a subject of debate. Clinical investigations have come to divergent conclusions and the true effect of radiotherapy (XRT) on flap survival is not definitely known. Most studies investigating the factor often have their methodological limitations such as lack of statistical power as a consequence of the overall low failure rates together with few irradiated cases. This study will attempt to address the question whether previous radiotherapy is associated with a significantly higher incidence of flap failure or not.

[METHODS] A systematic review and meta-analysis were conducted in concordance with the PRISMA protocol using the PubMed database. Fixed-effect and random-effect models were applied to obtain the odds ratio of total flap failure and partial flap failure between radiation and nonradiation groups. Statistical heterogeneity and publication bias were assessed and forest plots and funnel plots were constructed for graphic illustration.

[RESULTS] A total of 43 studies were included for qualitative and quantitative analysis involving 18,776 flaps in 17,532 patients. Patients with preoperative XRT were significantly associated with an increased risk for total (odds ratio fixed = 1.675, 95% confidence interval [CI] = 1.405-1.996, < 0.001) and partial free flap failure (odds ratio fixed = 2.161, 95% CI = 1.472-2.172, < 0.001).

[CONCLUSION] The study suggests that preoperative radiotherapy is associated with an increased risk for total and partial free flap failure. Further studies are needed to investigate the effect of total XRT dose and time after radiation on free flap outcome.