Impact of Microsurgical Reconstruction Timing on the Risk of Free Flap Loss in Acute Burns: Systematic Review and Meta-Analysis.

[BACKGROUND] Free tissue transfer is usually considered as a last resort in severe burn cases, when skin substitutes and local flaps are not viable options. Prior studies have demonstrated a free flap loss rate ranging from 0% to 44%. The aim of this study is to identify the ideal timing to perform free flap reconstruction in acute burn-related injuries to minimize free flap loss.

[METHODS] A systematic review and meta-analysis was performed and reported according to PRISMA guidelines. PubMed, Embase, Web of Science, and Cochrane Library databases were queried. The review protocol was registered on PROSPERO database (CRD42023404478). Three time intervals from day of injury were identified: (1) 0-4 days, (2) 5-21 days, and (3) 22 days-6 weeks. The primary outcome was total free flap loss.

[RESULTS] A total of 17 articles met inclusion criteria. The analysis included 275 free flaps performed in 260 patients (88% men, 12% women) affected by acute burn injuries. The pooled prevalence of free flap failure in the three time intervals (0-4 days, 5-21 days, and 22 days-6 weeks) were 7.32% [95% confidence interval (CI): 2.38%-20.37%], 16.55% (95% CI: 11.35%-23.51%), and 6.74% (95% CI: 3.06%-14.20%), respectively.

[CONCLUSIONS] Free flap reconstruction carries a high risk of failure in patients with acute burn. However, timing of the reconstruction appears to influence surgical outcomes. Free flap reconstruction performed between 5 and 21 days from burn injury had a trend toward higher flap loss rates and should be discouraged.