Original researchThe effect of relaparotomy timing on wound healing in an animal model

- We investigated the effects of timing of the surgery through the previous incision.
- The relaparotomies were performed on the 3rd, 15th or the 30th postoperative days.
- The breaking strength of the wound scar decreases and musculoaponeurotic gap increases by time between the two surgeries.
- Collagen type I and III increase with relaparotomy compared to first laparotomy.
- Histologically increased fibrosis and tissue defects were detected by relaparotomy.

Background: The effect of the timing of the second laparotomy on wound healing is not clear. In an experimental study in rats, we aimed to investigate the effect of timing on wound healing after reoperations on the same surgical site. Material and methods: Forty-eight rats were divided into four groups. The control group (GC) didn't have another laparotomy whereas the relaparotomies on the same surgical site were performed either on the 3rd, 15th or the 30th postoperative days in the three study groups (G3, G15, G30 respectively). The midline tension pressure, collagen types I, III and, histological analysis were performed from the specimens in order to assess the wound healing and strength. Results: The tensile strength was the highest in GC and decreased gradually in G3, G15 and G30, the difference between the groups did not reach statistical significance. Higher collagen levels, increased fibrosis, and large defects were observed in relaparotomy groups than CG. The musculoaponeurotic gap was shortest in GC when compared to other three relaparotomy groups (P < 0.001) and, it was the longest in G30 (P = 0.004 between G3 and G30). Conclusions: Although non-statistically significant the gradual decrease in the tensile strength and the statistically significant increase in the musculoaponeurotic gap with time point out the importance of the timing of relaparotomy in the healing process. Early relaparotomies do not disrupt the healing process as much as relaparotomy performed later.