gms | German Medical Science

Scar formation remains a potential problem after partial or full thickness skin loss. Factors influencing scar tissue formation have been recognized, most notably wound healing time and depth of the injury. These studies however did not specifically resolve the question as to whether depth of injury or time for complete reepithelization is the dominant factor influencing scar formation. The aim of this study was to examine the association between wound healing time and the quality of scar tissue formation. Scarring was assessed at 3 and 12 months after treatment in a prospective randomized control trial (EudraCT no. 2012-003390-26 and EudraCT no. 2012-000777-23) of 219 patients and consecutive 438 split thickness skin graft donor sites. The primary endpoint of the study was time to wound closure after topical intervention with topical betulin gel versus standard care. The quality of scar tissue was scored by a validated and reliable scar scale (3 (best) –12 (worst)) evaluating scar height, surface appearance and color match. We observed a mean time of wound healing of 15.8 days with a mean scar score of 6.89 at three month and 4.66 at 12 months. There was a significant (p<0.000001) and linear correlation between healing time and scar quality. Of particular note, at 12 months all sub parameters of the score demonstrated worsening with prolonged time to heal. Wounds treated with topical betulin gel (TBG) reepithelialized significantly (p<0.05) faster and showed significantly (p<0.05) less scaring. In this standardized wound model we could objectively demonstrate that epithelization time is an important factor influencing scar quality. In contrast to previous assumptions this correlation follows linearly. It is reasonable then to assume that clinical treatment strategies expediting healing will also improve scar outcome.