Investigation of the Optimal Pressure for Skin Grafting Using Negative Pressure Wound Therapy

Background: Recent studies suggest that negative pressure wound therapy (NPWT) is more effective than tie-over bolsters for skin graft fixation, improving graft take rates and reducing operation times. However, the relationship between negative pressure and compression pressure remains unclear. This study aims to explore that relationship. Methods: Study 1 investigated compression pressure at the thigh, anterior tibia, and posterior lower leg under varying negative pressure settings. Study 2 measured compression pressure at the anterior ankle joint and knee joint during flexion. Study 3 compared compression pressure between sheet skin grafts and grafts with drain holes. Results: Compression pressure did not strongly correlate with increasing negative pressure at body sites. At the dorsiflexed ankle joint, compression pressure decreased despite increased negative pressure, whereas at the knee joint, pressure increased with the flexion angle. In the sheet skin graft model with continuous sutures, compression pressure rose in response to negative pressure. Additionally, when a drain hole was created, a compression pressure of 20 mm Hg was achieved at a negative pressure of -25 mm Hg. Conclusions: The effectiveness of NPWT in skin grafting seems to result from adherence rather than direct compression because air is released between the graft and wound surface. The optimal negative pressure setting varied by graft type: 125 mm Hg for sheet grafts and 25 mm Hg for grafts with drain holes. These findings underscore the importance of adjusting negative pressure based on graft type and anatomical location to maximize the effectiveness of NPWT in skin grafting.