Effects of Remote Ischemic Conditioning on Flap Oxygenation in Patients Undergoing Head and Neck Reconstruction and Preoperative Radiotherapy: A Randomized Clinical Trial.

[BACKGROUND] Preoperative radiotherapy and ischemia/reperfusion (I/R) injury during free tissue transfer may impair tissue oxygenation and increase flap complications. Ischemic conditioning, which involves brief cycles of ischemia and reperfusion, mitigates I/R-induced tissue damage. It has demonstrated organ-protective effects in various clinical settings.

[PURPOSE] This study aimed to compare postoperative flap tissue oxygenation in patients with head and neck (HN) cancer who received preoperative radiotherapy and underwent free flap transfer, with or without application of remote ischemic conditioning (RIC).

[STUDY DESIGN, SETTING, AND SAMPLE] A randomized clinical trial included patients with HN cancer and preoperative radiotherapy who undergoing free flap reconstruction at Seoul National University Hospital between 2018 and 2024. Subjects who had any condition preventing RIC from being performed were excluded.

[INDEPENDENT VARIABLES] The predictor variable was intraoperative management. Subjects were randomly assigned to RIC or sham treatment.

[OUTCOME VARIABLES] The primary outcome was tissue oxygen saturation of the transferred flap measured on postoperative day 1. Secondary outcome was composite flap complications, including wound dehiscence, surgical bleeding control, flap revision, and reoperation.

[COVARIATES] The study covariates included demographic, surgical, and anesthetic variables.

[ANALYSES] Statistical analyses were conducted using independent t-test, Mann-Whitney U test, Pearson χ test, or Fisher's exact test. Values before and after free flap transfer were compared using paired t-test or the Wilcoxon signed-rank test. For repeated-measures variables, we used a linear mixed model. Statistical significance was set at P < .05.

[RESULTS] Forty-four patients were randomized, and 39 were analyzed. The median (interquartile range) patient age was 65.0 (56.0 to 70.0) years. Postoperative flap tissue oxygen saturation did not differ between the groups: median (interquartile range), 86.5% (68.5 to 95.0%) in the RIC group (n = 21) versus 84.0% (74.0 to 93.0%) in the sham group (n = 19) (P = .7). The RIC group had fewer flap complications than the sham group (4 [20.0%] vs 10 [52.6%], P = .034).

[CONCLUSIONS AND RELEVANCE] RIC did not improve the transferred flap tissue oxygenation in HN cancer patients who underwent preoperative radiotherapy and reconstructive surgery. However, fewer flap complications were observed in the RIC group than in the sham group, suggesting that RIC may serve as a protective strategy against I/R injury in selected patients.