Botulinum toxin for the prevention and healing of wound scars: A systematic review of the literature.

BACKGROUND Botulinum toxin injections have been investigated for the treatment or prevention of hypertrophic scars in several clinical studies. However, its clinical effectiveness has not yet been established. OBJECTIVE To examine all available evidence that support the use of botulinum toxin injections for the treatment or prevention of hypertrophic scars in current clinical practice. METHODS A systematic review searching the MEDLINE (1966 to 2014), Scopus (2004 to 2014), Popline (1974 to 2014), ClinicalTrials.gov (2008 to 2014) and Cochrane Central Register of Controlled Trials (CENTRAL) (1999 to 2014) databases together with reference lists from included studies was conducted. RESULTS Ten studies (255 patients) were included. Of these, 123 patients were injected with botulinum toxin type A, nine patients were offered botulinum toxin type B and the remaining 123 patients represented the control groups. Significantly improved cosmetic outcomes were observed among certain studies using the visual analogue scale (experimental group: median score 8.25 [range 6 to 10]) versus control group: median score 6.38 [range 2 to 9]; P<0.001) and the Stony Brook Scar Evaluation Scale (experimental group score: 6.7 versus control group score: 4.17; P<0.001) assessments. However, the methodological heterogeneity of the included studies, the lack of control group in the majority of them, the use of subjective scales of measurement and the frequent use of patient self-assessment precluded unbiased results. CONCLUSIONS Current evidence does not support the usage of botulinum toxin. Future randomized controlled trials are needed in the field to reach firm conclusions regarding its place in current clinical practice.