3. Discussion
redness, hypertrophic scars, inflammation, scars, paralysis, pain
SCAR, PROLIFERATION, INFLAMMATION, ADVERSE EVENTS, TRANSFORMING, SCAR
Health issues associated with chest binding have been documented among individuals [Recently, Botulinum toxin type A (BoNT-A) has shown promising effectiveness in scar prevention, and its underlying mechanisms have been extensively explored. The scar prevention benefits of BoNT-A have initially been attributed to the immobilization of the wound through temporary paralysis of underlying muscles [To begin with, BoNT-A is known to down-regulate the expression of transforming growth factor-beta 1 (TGF-β1), leading to reduced fibroblast proliferation and differentiation [To the best of our knowledge, this is the first randomized, double-blind, placebo-controlled study employing incoBoNT-A administration for scar prevention following female-to-male subcutaneous mastectomy. In our study, a separate-scar side design was employed, wherein a single patient served as both an intervention and a control group, effectively mitigating confounding factors in scar formation.Employing subjective scar assessments, the Vancouver Scar Scale (VSS) and the Patient and Observer Scar Assessment Scale (POSAS), a trend of increasing scores was observed at the 3-month mark. Because of natural wound healing and remodeling processes, around 3 months post-surgery there is an increase in collagen production, which is a key component of scar tissue. This trend mirrors the incidence rate of hypertrophic scars, which was approximately 60% after procedures like mammoplasty or median sternotomy at 3 months [Regarding the subjective evaluations using VSS and POSAS, our study’s outcomes indicated that only the VSS score at the study’s conclusion was significantly lower in the incoBoNT-A group in comparison to the control group. Above all, patients reported significantly higher satisfaction with the incoBoNT-A injected side compared to the control side at the end of the study.According to a recent systematic review by Zhang et al., 12 studies were included that investigated the postoperative administration of BoNT-A [Li et al. conducted a split-scar study on the chest wall area and reported significant improvements in the VSS score and patient satisfaction in the BoNT-A group compared to the control group at the 6-month follow-up [For a deeper comprehension of the non-neural mechanisms associated with the use of BoNT-A in scar management, it’s crucial to examine its impact on the wound healing process. One well-documented effect of BoNT-A is its ability to down-regulate the expression of Transforming Growth Factor-Beta 1 (TGF- β1), which in turn reduces fibroblast proliferation and differentiation [Several studies have examined the effect of BoNT-A on gene expression, and these studies have found that BoNT-A can inhibit particular genes that relate to scar formation. One important gene is PTEN (Phosphatase and Tensin homolog), which plays a crucial role in glial scar formation [In terms of objective evaluation, the redness of scars assessed by Colorimeter displayed statistically lower values in the incoBoNT-A group compared to the control group at 3 and 6 months. This finding could indicate the efficacy of incoBoNT-A in reducing inflammation and assisting immature scars in maturing with a diminished degree of discoloration [Overall, our study underscores that incoBoNT-A has the potential to ameliorate both scar severity and appearance. Over the entire study duration, no serious adverse events were observed. Furthermore, while patients did not regain normal sensation in the surgical scar area because of the operation, local pain during injection was manageable.It is important to acknowledge that scar formation can be influenced by various factors, including different anatomical locations and ethnicities. Notably, many of the positive studies on scar improvement have focused on facial scars [This study does have certain limitations that should be acknowledged. One primary limitation is the relatively small sample size and the relatively short follow-up duration, which was restricted to only 6 months. Further investigations with larger participant cohorts and extended follow-up periods are warranted to establish the long-term effectiveness of BoNT-A in scar reduction. Moreover, considering the potential for optimizing treatment outcomes, exploring the feasibility of repeat injections should be taken into consideration.Another aspect to consider is the timing of BoNT-A administration. While previous studies have predominantly administered BoNT-A either before wound closure, immediately after wound closure, or during the early postoperative phase [