Development of a histomorphologic scale to quantify cutaneous scars after burns

Objective: Cutaneous wound healing in adults invariably results in scarring ; however, there are few scales to quantify the degree of such scarring. Th e authors developed a histomorphologic scale for quantifying scarring after cutaneous burn injury. Methods: As part of a randomized trial comparing a variety of burn therapies, 40 partial-thickness burns were created on the b acks and flanks of anesthetized pigs and treated with a tissue adhesive, an tibiotic ointment, occlusive dressing, or dry gauze. Gross scar appearance was independently assessed by two investigators at 90 days on a 100-mm visu al analog scale (VAS) marked "best appearance" at the high end. One of the investigators repeated the observation 30 days later. Full-thickness biopsi es were taken 90 days after injury and evaluated histologically by a dermat opathologist for the presence of hyperkeratosis, epidermal hyperplasia, pre sence and. depth of scar (defined as abnormally oriented collagen under pol arized light), fibroplasia, vascular proliferation, and absence of adnexa, including hair follicles, apocrine glands, and smooth muscles. One point wa s assigned for each category in the presence of a normal finding, whereas a n abnormal finding was assigned a score of zero. The normal dermis (absence of abnormal collagen) was given a score of 3, while decreasing scores of 2 to 0 were given for progressively deeper scars (i.e., 2 for papillary derm is, 1 for upper half of reticular dermis, and 0 for deep dermal lower half) . The total histomorphologic score was derived by adding the scares on the individual items. The score ranges from 0 to 10 from worst scarring to abse nce of scarring, respectively. A subset of observations was evaluated a sec ond time by one of the observers one month later Intraobserver reliability of the histomorphologic scale was assessed with Spearman's correlation. Int er- and intraobserver Pearson's correlations for the gross scar VAS were ca lculated, and the correlation between gross and histomorphologic scores was assessed. Results: Intraobserver correlation for individual histomorpholog ic categories ranged from 0.19 to 1.00. Intraobserver correlation for the t otal histologic score was 0.95. Inter- and intraobserver correlations for t he gross scar VAS were 0.8 each. Correlation between the histomorphologic s cale and the gross scar VAS was 0.38. Conclusions: A new reliable histomorp hologic method for quantifying and scoring cutaneous scars is described tog ether with a reliable scar VAS. However, these two scales are not highly co rrelated.