Randomized Controlled Trial Examining the Efficacy of Botulinum Toxin in Biopsy Scar Minimization

Study Overview
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Brief Summary
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The proposed study seeks to evaluate the scar reduction capacity of BTA on excision/biopsy wounds compared to the control (normal saline) in a double-blinded randomized control trial. It will expand upon previous studies that have already demonstrated the safety and good tolerance profile of BTA. We will be conducting a split-scar study/study involving two biopsy sites in a singular patient, allowing them to serve as their own control. In keeping with the results from previously conducted studies, we hypothesize that the wounds treated with BTA will have significantly less evidence of scar formation than those sites treated with normal saline.

Detailed Description
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The process of scar formation is denoted by three stages: inflammatory, proliferative, and remodeling. The former phase is characterized by the activation of the extrinsic clotting pathway and subsequent materialization of a fibrin plug, after which neutrophils facilitate the degradation of pathogens and secretion of signaling molecules that commence the proliferative phase. The fibrin plug is then replaced by granulation tissue comprised of macrophages, fibroblast, and endothelial cells in the proliferative phase. Through the release several growth factors, existing macrophages induce laying down of type III collagen by fibroblasts, and keratinocytes work in tandem to approximate wound edges. Lastly, during the remodeling phase, cellular apoptosis causes granulation tissue formation to subside, type III collagen is replaced by a more durable collagen type I, and myofibroblasts help to condense the scar size.1,2 While scarring in its non-pathological forms is an innate and appropriate bodily response to cutaneous injury, scar development and persistence can have negative physical and psychological implications, including decreased range of motion secondary to contracture, disfigurement, and impaired quality of life.1,3-5 Thus, for medical and cosmetic purposes alike, curtailing scar formation is important aspect of patient management, and treatment aimed at both prevention and resolution is an evolving subject in the medical discourse. Credence has been given to the use of botulinum toxin A (BTA) in scar minimization, a more novel therapy, and has proved efficacious in several studies including those examining BTA in the treatment of keloids and hypertrophic scars, mammoplasty and abdominoplasty surgery scars, and post-operative scars generally.6-9 The suggested mechanisms for this phenomenon involve inhibition of pre-synaptic acetylcholine channels that lead to muscle paralysis and relaxation of perpendicular wound tension; this particular mechanism is likewise theorized to mitigate collagen overproduction. Another hypothesis for explaining the ability of BTA to reduce scar appearance is the direct modulation of fibroblast activity.6

Official Title
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Randomized Controlled Trial Examining the Efficacy of Botulinum Toxin in Biopsy Scar Minimization

Conditions
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Scar, Hypertrophic Scar

Intervention / Treatment
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* Drug: Botulinum Toxin
* Drug: Normal saline


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy Individuals age 18 and older Able to understand the requirements of the study and its associated risks Able to complete and sign a consent form Exclusion Criteria: Allergy to botulinum toxin Currently pregnant or breastfeeding Myasthenia gravis Previous injection of botulinum toxin in the specified treatment areas within 6 months prior to enrollment Unable to follow up 6 months after biopsy procedure Refusal to participate in the trial History of keloid or hypertrophic scars Eaton-Lambert Syndrome Amyopathic Lateral Sclerosis

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: We will be conducting a split-scar study/study involving two biopsy sites in a singular patient, allowing them to serve as their own control.
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Botulinum toxin<br>Biopsy site receiving botulinum toxin Following the biopsy closures, one of two biopsy sites (left or right) will be selected to receive 30u (0.3cc) of botulinum toxin injected into the suture line at a depth of PPD bleb. The treatment for each wound site will be randomized (left versus right) and blinded but consistent throughout dosing. | Drug: Botulinum Toxin<br>* We will be comparing botulinum toxin following the biopsies to placebo injection. We will then compare photos of each biopsy site at set intervals following the procedure.<br>* Other names: abobotulinumtoxinA;|
| Placebo Comparator: Placebo<br>Placebo Comparator: Biopsy site receiving placebo Following the biopsy closures, the other biopsy site will receive 30u (0.3cc) of bacteriostatic normal saline injected into the suture line at a depth of PPD bleb. | Drug: Normal saline<br>* Normal saline will serve as the placebo control on the contralateral side of the back.<br>* Other names: Placebo;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Primary Outcome Measure | Modified Patient and Observer Scar Assessment Scale v2.0 (POSAS) | 3 months | 
| Primary Outcome Measure | Modified Patient and Observer Scar Assessment Scale v2.0 (POSAS) | 6 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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botulinum toxin, scar prevention, scar formation