Assessment with the dermal torque meter of skin pliability after treatmentof burns with cultured skin substitutes

The assessment of visco-elastic (V-E) properties in cutaneous scars is crit ical to reduction of impairment and restoration of function after grafting of excised burns. Cultured skin substitutes (CSS) that consist of autologou s keratinocytes and fibroblasts attached to biopolymer substrates are alter natives for permanent closure of excised, full-thickness burns, but assessm ent of scarring has been subjective. V-E properties of CSS were measured wi th a Dia-Stron Dermal Torque Meter (DTM 310, Dia-Stron, Ltd, Broomall, Pa), which applies a constant torque (10 mNm) for a fixed interval (10 seconds) and measures rotational deformation and recovery. Parameters of skin defor mation were measured in patients (n = 10) after grafting of CSS or meshed s kin autograft. Native human skin (NHS) of healthy volunteers (n = 13) serve d as the control. Skin healed after treatment with CSS or autograft was eva luated for 1 year or longer after grafting. Elastic stretch (Ue), viscous s tretch (Uv), total extensibility (Uf), elastic recovery (Ur), total recover y (Ua), and residual plasticity (R) were measured as degrees of rotation, w ere tested for significance (P < .05) bg Student t test comparisons between treatment groups and controls, and were subjected to regression analysis. Assessment of burn scar with the Dermal Torque Meter detected time-dependen t increases of all individual parameters of V-E properties for both CSS and autograft during the first year after grafting. At I year or later, no sta tistical differences were found between CSS and autograft for individual pa rameters, but Ue and Ur for autograft were significantly lower than for NHS . At 1 year or longer, autograft was significantly different from CSS or NH S, with a greater ratio of Uv to Ue, and both graft types had a lower ratio of Ur to Uf than NHS had. These results suggest that instrumental measurem ent of scar pliability may increase objectivity in assessment of patient re covery and establish an absolute scale for quantitative analysis of V-E pro perties in skin after grafting of conventional or alternative skin substitu tes.