Analysis of biomonitoring data after full-thickness skin grafting.

Skin graft vascularization is investigated mainly by histological evaluation. Immunohistochemical analysis has been conducted only in mice. Transcutaneous oxygen tension (TcPO2 ), which is an index of blood flow, has not been evaluated in skin grafts and only a few studies have reported biologic monitoring data using color tone evaluation and surface temperature. In humans, these tests can be performed non-invasively. To evaluate human skin graft vascularization, we analyzed biomonitoring data after skin grafting. We evaluated 14 patients who underwent skin grafting surgery at Nagoya City University Hospital. The TcPO2 , color tone, surface temperature, and dermoscopic observations at recipient sites were measured at postoperative day (POD) 4, 6, and 11. Mean TcPO2 levels at POD4, 6, and 11 were 12.7, 15.2, and 33.5 mmHg, respectively, and significantly higher at POD11 than at POD4 (p = 0.003, Steel-Dwass test). Dermoscopic observation revealed gradually increasing redness and yellowness. Color tone evaluation measured by spectrophotometry supported the appearance. The a*(redness) value at POD4, 6, and 11 was 6.19, 9.20, and 11.27, respectively, and significantly higher at POD11 than at POD4 (p < 0.001, Steel-Dwass test). The b*(yellowness) value at POD4, 6, and 11 was 8.83, 9.24, and 13.02, respectively, and significantly higher at POD11 than at POD4 (p = 0.020, Steel-Dwass test). The surface temperature did not significantly differ between graft and control sites. These findings suggest that skin graft vascularization started by POD6 and stabilized by POD11. Because TcPO2 increases after POD4, skin grafts should remain undisturbed until at least POD11.