The effect of local insulin injection on the healing process of split thickness skin graft donor site: a randomized, double-blind, placebo control clinical trial

Background Wound site coverage by a split-thickness skin graft (STSG) is an effective technique after reconstructive surgery. Previous studies have been suggested that insulin is a stimulator for skin wound healing. This study was aimed to determine the effect of local insulin injection on the improvement of STSG donor site wound healing. Methods A randomized clinical trial was performed in patients undergoing STSG in 2019. The donor site of patients was divided into control and case segments. Two cubic centimeters of NPH insulin was injected at the case segment with a concentration of 1 IU/ml and normal saline was injected at the control segment by the same volume. The wound site epithelialization area was calculated by ImageJ (R) software at the 7th, 14th, and the 21st day after the intervention. The epithelialization area of the case and control group was compared by SPSS software. Results Epithelialization area was improved at the 21st day compared to 14th day and 7th day. In addition, the amount of epithelialization was significantly higher at the case segment in the 7th, 14th, and the 21st day after the injection with the P values of 0.006, 0.001, and < 0.0001, respectively. Moreover, there was not any sign of hypoglycemia and other complications in patients. Conclusion Subdermal injection of insulin may improve the wound site epithelialization in the post-operative period. Level of evidence: Level I, therapeutic study.