Trolamine/sodium alginate topical emulsion versus bacitracin/polymyxin b ointment in second-intention healing following mohs micrographic surgery

Journal of Drugs in Dermatology, May, 2008 by Leon H. Kircik

Abstract

Background: Second-intention healing (SIH) is a common and acceptable method of wound care following Mohs

micrographic surgery.

Objective: To compare the efficacy and tolerability of a topical trolamine/sodium alginate emulsion (TAE) and bacitracin zinc/polymyxin B sulfate (BPB) ointment for SIH in patients requiring Mohs micrographic surgery for nonmelanoma skin cancers of the face.

Methods: Eligible patients (N=25) were randomized to treatment with either a TAE or BPB ointment applied once daily for 6 weeks in an investigator-blinded study. Patients were assessed for 12 weeks postoperatively.

Results: The topical TAE appeared to reduce wound size more rapidly than BPB ointment during the first 6 weeks of the study, although differences between the treatments were not statistically significant. The investigator's global assessment of treatment also indicated a trend in favor of the TAE. Both topical preparations were well tolerated.

Conclusions: The topical TAE appears to be equally or more efficacious than BPB ointment for SIH in patients undergoing Mohs micrographic surgery for nonmelanoma skin cancers. Further research with larger study groups is needed to confirm the potential of a TAE in this setting.

Introduction

Second-intention healing (SIH) is a common and acceptable method of wound care following Mohs micrographic surgery (MMS). (1-3) The key to successful wound healing by SIH is the provision of a moist environment to keep the wound hydrated; an antibiotic ointment under occlusion is often used to help prevent infection. A nonantibiotic preparation commonly used for wound repair is a topical water-based emulsion containing trolamine and sodium alginate (TAE; Biafine(R)). In human epidermal wounds, this preparation has been shown to be chemotactic for macrophages and increase the inter-leukin-l/interleukin-6 (IL-l/IL-6) ratio, which suggests that the mode of action in enhancing wound repair is related to the effects on inflammatory cell migration and cytokine release. (4) When used for wound healing, TAE is advantageous because it does not contribute in any way to bacterial resistance, as it does not contain an antibiotic. (5)

In the US, a TAE is approved for the management of superficial and full-thickness wounds, dermal ulcers, graft sites, first-degree and second-degree burns, and radiation-induced skin toxicity. As of yet, there has been little research on its efficacy in SIH following MMS. This randomized, pilot study was designed to evaluate the efficacy and tolerability of a topical TAE compared with an ointment containing bacitracin zinc/polymyxin B sulfate (BPB; Polysporin(R)) for SIH in patients undergoing MMS for nonmelanoma skin cancers.

Methods

A randomized, investigator-blinded, parallel-group study of 12 weeks' duration was undertaken. Patients eligible for the study were scheduled to undergo MMS for nonmelanoma skin cancers of the head and neck. The study was approved by the institutional review board and performed according to good clinical practice guidelines and applicable regulatory requirements. All patients provided informed consent prior to undergoing any study procedures.

Patients and Treatment

Adult male or female subjects who required MMS for a nonmelanoma skin cancer considered to result in a final defect size less than 15 mm were randomized equally, via the use of treatment assignment numbers, to once-daily applications of either the TAE or BPB ointment. Women who were pregnant (ie, had a positive urine pregnancy test at baseline), breast-feeding, or of childbearing potential and not practicing a reliable method of contraception were excluded, as were patients with any known allergy or sensitivity to the test medications, those with a history of alcohol or drug abuse, or other medical conditions considered to contraindicate participation in the study, and those with a history of poor cooperation, noncompliance with medical treatment, or un-reliability. Other therapies not considered to interfere with the response to treatment were allowed at the discretion of the investigator.

Study medications were blinded to the investigator, but not to the study nurse or patient. Following MMS, patients were instructed to apply the medication to the wound area in an 1/4-inch thick layer once daily each morning until the wound had healed or week 6, whichever occurred first. Prior to each application, patients were instructed to gently wash the face and wound area with soap and water, and then pat dry with a soft towel. After medication application, a moistened gauze pad was applied, which was to remain in place until the following morning.

Efficacy and Safety Assessments

During the 12-week study, patients were evaluated at weeks 0 (baseline), 3,6, and 12. Photographs of the wound were taken at baseline and each follow-up office visit. At weeks 3, 6, and 12, the investigator determined the wound size by measuring its length and width; global treatment effectiveness was assessed on a 4-point scale (0=not effective at all, l=slightly effective, 2=moderately effective, and 3=very effective). In addition, an assessment on a 4-point scale (0=none to 3=severe) was made of the application site with levels of erythema, erosion, ulceration, inflammation, swelling, infection, crusting, necrosis, peeling, contact dermatitis, hyperpigmentation/hypopigmentation, and scarring. Patients were also asked to rate levels of irritation, itching, burning, tenderness, and pain at the application site using the same 4-point scale.