Silicon gel sheeting for preventing and treating hypertrophic and keloid scars

BACKGROUND: Keloid and hypertrophic scars are common and are caused by a proliferation of dermal tissue following skin injury. They cause functional and psychological problems for patients, and their management can be difficult. The use of silicon gel sheeting to prevent and treat hypertrophic scarring is still relatively new, and started in 1981 with treatment of burn scars. OBJECTIVES: To determine the effectiveness of silicon gel sheeting for: (1) prevention of hypertrophic or keloid scarring in people with newly healed wounds (e.g. post surgery); (2) treatment of established scarring in people with existing keloid or hypertrophic scars. SEARCH STRATEGY: Trials were identified from searches of the Cochrane Wounds Group Specialised Register (searched November 2007), the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 4, 2007); MEDLINE (2005 to November 2007); EMBASE ( 2005 to Week 46, 2007); CINAHL (2005 to November 2007) and reference lists of articles and relevant reviews. The major supplier of silicon gel sheeting (Smith and Nephew) was approached for details of unpublished, ongoing and recently published trials. SELECTION CRITERIA: Any randomised or quasi-randomised controlled trials, or controlled clinical trials comparing silicon gel sheeting for prevention or treatment of hypertrophic or keloid scars with any other non surgical treatment, no treatment or placebo. DATA COLLECTION AND ANALYSIS: All relevant trials were assessed for methodological quality. Data were extracted independently by both review authors using a standardized form, and the results cross-checked. All trials, meeting the selection criteria were assessed for methodological quality. MAIN RESULTS: Fifteen trials, involving 615 people, ranging in age from 2 to 81 years, were included in the review. The trials compared adhesive silicon gel sheeting with control; non-silicon gel sheeting; silicon gel plates with added Vitamin E; laser therapy; triamcinolone acetonide injection, and non-adhesive silicon gel sheeting. In the prevention studies, when compared with a no treatment option; whilst silicon gel sheeting reduced the incidence of hypertrophic scarring in people prone to scarring, (RR 0.46, 95% CI 0.21 to 0.98) these studies were highly susceptible to bias. Silicon gel sheeting produced a statistically significant reduction scar thickness (RR -1.99, 95% CI -2.13 to -1.85) and colour amelioration (RR 3.05, 95% CI 1.57 to 5.96) but again these studies were highly susceptible to bias. AUTHORS' CONCLUSIONS: Trials evaluating silicon gel sheeting as a treatment for hypertrophic and keloid scarring are of poor quality and highly susceptible to bias. There is weak evidence of a benefit of silicon gel sheeting as a prevention for abnormal scarring in high risk individuals but the poor quality of research means a great deal of uncertainty prevails.