Long‐term improvement in the appearance of hypertrophic scars following a single treatment with acoustic subcision—A single center proof‐of‐concept study

Abstract

Introduction and Objectives Fibrosis, including hypertrophic scar formation, is a pathological condition characterized by excessive production and accumulation of collagen, and loss of tissue architecture, in response to wound healing. Alterations in the extracellular matrix (ECM) biomechanical properties may be important in modulating myofibroblasts and fibrosis formation. The acoustic subcision device uses rapid acoustic pulse technology to noninvasively improve the appearance of hypertrophic scars through both microdisruption of scar tissue matrix and downregulation of fibrotic fibroblasts leading to scar remodeling. The objective of this single‐site proof‐of‐concept IRB‐approved human clinical study was to evaluate the efficacy of acoustic subcision device for the improvement in the appearance of hypertrophic scars. Method Eleven hypertrophic scars in 10 participants were treated with a single 6‐minute acoustic subcision application without anesthesia. Posttreatment adverse events (AEs) and tolerability were recorded. At 12 and 89 weeks posttreatment, scar heights and volumes were measured, and participant satisfaction questionnaires were completed. Finally, at the last visit the scar appearance was assessed by the Principal Investigator (PI) using the Mecott Modified Scar Scale (MMSS). Results Immediately following the acoustic subcision treatment, only mild, moderate erythema or pinpoint bleeding were noted. The treatment sessions were considered tolerable by all participants with an average pain score of 2.2 (on a 0–10 pain score with 10 being the worse possible pain). The 12‐ and 89‐week assessments demonstrated mean height reductions of 46.3% and 56.8%, respectively from baseline. The differences in scar height were statistically significant (p < 0.01). The 12‐ and 89‐week assessments demonstrated a mean volume reduction of 63.2% and 58.1% respectively from baseline. The differences in the scar volume were statistically significant (p < 0.001). The PI graded an average improvement of 33.7% in scar appearance using the MMSS, a statistically significant change (p < 0.001). Finally, >90% of participants reported satisfaction with the improvement in their scar. Conclusion This proof‐of‐concept study showed that a single noninvasive acoustic subcision treatment session can safely provide statistically significant improvement in the appearance of hypertrophic scars with minimal treatment pain and meaningful participant satisfaction. More work is needed on a larger number of scars to verify this finding. Further improvement in appearance is expected with multiple acoustic subcision treatments and/or treatments in combination with currently available options. Additional trials to verify this are planned.

Unremitting pro‐inflammatory T‐cell phenotypes, and macrophage activity, following paediatric burn injury

“…Macrophage‐secreted TGF‐β contributes to fibroblast activation, which causes scarring and contractures 57,58 . Unsurprisingly, all of the burn patients in this study had measured scar thickness of more than 3 mm, all showed delayed healing, and all had repeated burn procedures; these are all predictors of hypertrophic scarring 59,60 . MIP‐1 is a macrophage and monocyte chemoattractant.…”

“…57,58 Unsurprisingly, all of the burn patients in this study had measured scar thickness of more than 3 mm, all showed delayed healing, and all had repeated burn procedures; these are all predictors of hypertrophic scarring. 59,60 MIP-1 is a macrophage and monocyte chemoattractant. It has been shown that lower levels can reduce angiogenesis, macrophage recruitment, and contribute to delayed healing.…”

MMP2 loss leads to defective parturition and severe dystocia in mice

“…As MMP2 has been previously shown to degrade collagen as one of its substrates [33,34], and as collagen accumulation is associated with fibrosis in different tissues [35,36], we next asked whether the observed pathophysiology in the MMP2-nulls is coupled with accumulation of collagen in the uterine wall. Masson’s Trichrome staining for collagen fibrils was performed on transverse sections from nulliparous WT and mmp2 -/- uteri at 12M of age, demonstrating an increase in collagen fibrils in mmp2 -/- tissue as shown by the increased blue staining mostly in the circular myometrium layer, compared to WT (Fig.…”

“…As MMP2 has been previously shown to degrade collagen as one of its substrates [33,34], and as collagen accumulation is associated with fibrosis in different tissues [35,36],…”

Mmp2 Deficiency Leads to Defective Parturition and High Dystocia Rates in Mice

“…Collagen accumulation in associated with fibrosis in several tissues, including the liver, kidney and uterus [32][33][34][35][36]. For example, Xu et al showed enhanced collagen expression and fibrosis in the mouse uterus, which are associated with Notch1 signaling [35].…”