LAUSR

BACKGROUND AIMS There is currently no definitive treatment for the painful scar. Autologous adipose tissue grafting (AATG) as a treatment option for scars has become increasingly popular and there is now an abundance of evidence in the literature that supports its application. Some studies suggest that human adipose tissue is a rich source of multipotent mesenchymal stromal cells. To our knowledge, there is currently no systematic literature review to date that examines the effectiveness of AATG for reducing pain in scars. Our novel systematic review aims to examine clinical studies on the use of AATG in the treatment of the painful scar. METHODS A literature search was performed using the following databases: PubMed, Cumulative Index to Nursing and Allied Health Literature, Web of Science, Medline, Cochrane library and Embase. The following key words and search terms were used: adipose stem cells, scar, pain, autologous fat grafting, scar management and neuropathic pain. Human interventional studies using autologous adipose tissue grafting for the treatment of painful scars including case series, case-control, cohort studies and randomized controlled trials were reviewed. RESULTS A total of 387 studies were found and 18 studies from January 1990 to January 2019 were identified as relevant for the purpose of this systematic review. Two studies were evidence level V, seven were evidence level IV, six were evidence level III, two were evidence level II and one was level I. A total of 337 scars were assessed in 288 patients for improvement in pain after scar treatment using adipose tissue grafting. An improvement in the analgesic effect was recorded in 12 of the 18 studies with adipose tissue grafting. A total of 233 of the 288 treated subjects responded with reduction in pain, whereas the rest did not. We carried out a pooled analysis of the studies and observed an odds ratio of 3.94 (P = 0.00001) when comparing pain reduction to no change in pain. CONCLUSIONS We conclude that AATG is a promising and safe modality for the treatment of the painful scar. There is an abundance of low-level evidence to support its use as an alternative treatment but there is a lack of high-level evidence at present to support its standard use. Future long-term randomized controlled trials with analgesic scores as the primary outcome measures are required to assess long-term efficacy.