Force Modulating Tissue Bridges for Reduction of Tension and Scar: Finite Element and Image Analysis of Preclinical Incisional and Nonincisional Models

Abstract

Background Force modulating tissue bridges (FMTB) represent a new class of combined wound closure and scar reduction device designed to optimize the tension milieu of the healing wound. Objectives Engineering analysis and testing in both intact skin and incisional models was undertaken to assess changes in tissue tension associated with device placement and compare to standard suture closure. Methods Nonlinear, large deformation finite element analyses (FEA) were performed to compare the strains applied to tissues with sutures and FMTB. In the incisional model, a freshly euthanized Yorkshire pig received full thickness cutaneous incisions followed by alternating closure with sutures and FMTBs. FMTBs were also applied to intact adult human skin after pattern application. In each of the experiments, photographs were taken preapplication and postapplication and the resultant dot grid pattern changes were analyzed by image recognition algorithms to calculate applied strains. Results FEA indicate compressive stresses at the tissue:suture interface on the order of 4000 mmHg and 20 mmHg at the tissue:FMTB interface. Strain analysis of the sutures and FMTBs applied in the incisional lab testing indicated imposed strains on the tissues of around 40%, with FMTBs providing 10% more compression than sutures and 25% more compression between the applied devices (P = 0.000057). In the longitudinal study, tension reduction of the order of 30% was maintained over the treatment period of 10 days to verify device efficacy. Conclusions FMTBs provide wounds while simultaneously modulating skin tension and thus have the potential to improve scar appearance.