Purpose: The vascular carrier is believed to a play crucial role in revascularization of prefabricated skin flap. In the clinical setting, vascular pedicles raised in continuity with a muscle cuff or fascia may result in a bulky pedicle and donor-site morbidity. Small intestinal submucosa (SIS) is a biomaterial that can provide a natural scaffold for cells migration and induce neovascularization. In this study, we examined the feasibility of SIS as a carrier in skin flap prefabrication.

Methods: Thirty-eight adult Sprague-Dawley rats were randomly divided into five groups. The right saphenous vascular bundle was used as the vascular carrier. In group 1, an arteriovenous fistula was made by anastomosis of saphenous artery and vein. A SIS patch (1.5 x 2 cm²) was placed underneath the vascular bundle. At 2 weeks postoperatively, the same size of medial thigh flap including SIS was raised and replaced; In group 2, the vascular bundle was isolated and laid over the SIS patch. The distal saphenous vessels were ligated when the flap was raised; In group 3, arteriovenous fistula was made without SIS implant. After 2 weeks maturation, the flap was raised with only the vascular bundle; In group 4, the flap was raised with only the vascular bundle and the distal end of the vascular bundle was ligated; In group 5, a SIS was implanted, and the flap including the SIS patch was raised and replaced without vascular pedicles. The survival of the flaps and histology were evaluated at 7 days after flap replacement.

Results: The average survival area in group 1 was 98.8%, and in group 2 was 87.5%. There was no significant difference of survival area between these two groups (p>0.05). The mean survival areas in group 3 and 4 were 60.0% and 25%, respectively, which were significantly lower than groups 1 and 2 (p<0.05, p<0.01). Histology showed that the SIS patch was incorporated into the adjacent connective tissue, and a consistent pattern of exaggerated amounts of neovascularization was observed in this biomaterial and subcutaneous tissue of the prefabricated flaps with SIS implant.

Conclusion: This study demonstrated that small intestinal submucosa can incorporate into the adjacent tissue and induce angiogenesis in flap prefabrication. This biomaterial can provide a scaffold for supporting and enhancing the survival of prefabricated skin flap.