Wound Healing in Partial-Thickness Burn Wounds Treated With Collagenase Ointment Versus Silver Sulfadiazine Cream

Abstract

During burn care the wounds must be repeatedly debrided of adherent and loose debris until the decision is made to surgically excise and graft the wound or to await epithelializatdon. Though native proteolytic enzymes in the skin or those produced by colonizing bacteria can speed eschar separation, the use of exogenous enzymes for wound debridement may accelerate wound cleaning and healing. Collagenase digests native and denatured collagen in necrotic tissue. This multicenter trial of 79 patients with partial-thickness wounds compared the efficacy of collagenase ointment applied with polymyxin B sulfate/bacitracin powder with the efficacy of standard topical antimicrobial therapy (control) in which silver sulfadiazine cream (1%) was used to debride paired burn sites. Patients selected for the study had two noncontiguous, partial-thickness, comparably sized, and anatomically similar burn wounds. Ages of patients ranged from 5 to 60 years (mean 33 years). The total body surface area burned ranged from 2% to 30% (mean 13.6%). Mean burn sizes used for study treatment were 366 cm2(26 to 2310 cm2) for collagenase sites and 355 cm2 (26 to 2394 cm2) for control sites. Sites on each patient were randomly assigned to treatment with either collagenase or control. Endpoints were time to clean wound bed (absence of retained debris) and time to healing (complete epithelialization). The sites treated with collagenase cleaned in less time (mean 9.3 days) than the control sites (mean 11.6 days). Similarly the collagenase sites healed faster than the control sites (mean 19 vs 22.1 days). When paired treatment sites were compared within each patient, proportionately more of the sites treated with collagenase cleaned (p < 0.001) and healed (p < 0.001) before similar burns sites treated with silver sulfadiazine. More control sites required surgical intervention than collagenase sites, but significance was not reached. In a subset of 19 patients (mean total body surface area 15.2%), we compared pain ratings reported from both study sites with the use of a visual analog scale at three time points: during cleansing and debridement, 15 minutes after treatment, and 30 minutes after treatment. Collagenase sites were routinely judged to have “thinner” eschar than the control sites and thus required less pain-inducing mechanical debridement. Patients did not report a difference in pain between sites during or after dressing application, except for day 2 when patients reported less pain at the collagenase site during debridement (p < 0.05). The results of this multicenter study suggest that the use of collagenase for treatment of partial-thickness burns is efficacious and minimizes discomfort.