Measures of wound healing rate

Abstract

Several wound healing rate measures have been introduced to date, with the main goal to enable quantification of effects of various therapeutic modalities on healing of skin wounds. Different definitions of wound healing rate render comparison of clinical results impossible. The goal of the authors' study was to discuss measures of wound healing rate based on wound size. Measures founded on two wound size measurements and measures based on several wound area measurements over time. Wound healing data obtained in a clinical trial revealed exponential behaviour of the healing process with delay of wound healing process initialisation. Due to the nonlinear nature of the healing process, it was concluded that wound healing rate cannot be correctly determined from just two wound size measurements. Optimally the wound healing rate measure should be deduced from the wound healing model with three parameters. Fitting with the delayed exponential model requires at least four wound size measurements over time. In further analysis the authors compared the wound healing measure based solely on wound area measurements with the measure additionally containing wound shape information. It was found that wound perimeter data does not facilitate wound healing rate expression. Thus it was concluded that wound area measurements should be transformed to percent of initial wound area and fitted to delayed exponential model. The slope of the curve fitted to the transformed wound area measurements over time after initial delay well describes wound healing rate.