Statistical Study on Negative Pressure Strength during Skin Graft Fixation

Abstract

Objectives: Recent studies have reported that negative pressure wound therapy (NPWT) is useful for skin graft fixation. However, there is no reliable evidence of the optimal negative pressure strength during fixation. We verified the relationship between negative pressure strength and the engraftment rate retrospectively.

Methods: This study included 130 patients who underwent skin graft fixation using NPWT. All cases were divided into full-thickness skin graft (FTSG) and split-thickness skin graft (STSG) groups and further classified into three subgroups based on negative pressure strength as follows: high-pressure (≥100 mmHg), moderate-pressure (≥75, <100 mmHg), and low-pressure (<75 mmHg). The engraftment rates of each subgroup were compared and evaluated on a three-point scale of "good," "fair," and "poor"; the proportion of cases with "good" engraftment was defined as the engraftment rate.

Results: In the FTSG group, the engraftment rates were 40.0%, 82.4%, and 100% in the high-, moderate-, and low-pressure subgroups, respectively; in the STSG group, the engraftment rates were 85.9%, 70.8%, and 87.5% in the high-, moderate-, and low-pressure subgroups, respectively. The multiple comparison test observed no significant differences in both group. However, when FTSG was reclassified with a cutoff value of 100 mmHg, the engraftment rate was significantly lower in the high-pressure than in moderate- and low-pressure subgroups.

Conclusions: It is recommended to set negative pressure strength <100 mmHg for FTSG and to set that while prioritizing fixation for STSG.