Botulinum toxin A for wound healing

May 8, 2019

Small study suggests botulinum toxin A injections may improve skin scarring.

Injecting botulinum toxin type A into areas where scarring can occur from facelift surgery yields noticeable improvements in the quantitative evaluation and subjective appreciation of postsurgical scars, according to a small study published in the American Journal of Cosmetic Surgery.

Poor scarring is among the complications that can result from facelifting surgery. To limit scar formation and visibility, surgeons carefully select incision sites and suturing materials, focus on surgical technique, use fibrin spray during surgery, as well as use compression bandages, antibiotic ointments and silicone gel on the wound after surgery.

Despite all these precautions, it has been suggested that by tensing muscles around scars, patients can negatively impact healing.

Botulinum neurotoxin type A relaxes muscles and could improve scars for that reason. But this paper’s author Alexandra Chambers, M.D., Ph.D., medical director, MAP Hospital, London, UK, found there might also be benefits from using botulinum neurotoxin type A at the cellular level.

Dr. Chambers used Bocouture, the botulinum toxin type A (150 kD) neurotoxin by Merz Pharma Group approved in Europe for the treatment of upper facial lines (horizontal frown lines, lateral periorbital lines and glabellar frown lines). The Merz Aesthetic botulinum type A neurotoxin product approved in the U.S. is Xeomin, incobotulinumtoxinA.

The double-blinded study included 15 women, ages 47 to 65 years, who had just had routine facelift procedures using periauricular incisions. Patients were divided into three groups of five women each. All received active drug injected at three points around one ear and a placebo of bacteriostatic normal saline injected in the same manner around the other. One group of women received 5 units (U) of the neurotoxin, the second group 15 U and the third 25 U.

At six weeks post-surgery, Dr. Chambers writes that she observed reduced inflammation in wounds treated with the neurotoxin. Overall, she noted the best results in the 15 U group.

When she measured scar width and thickness using quantitative methods, the author found smaller scar widths on the active side in the 5 U, 15 U and 25 U groups. However, the best results were in the 15 U and 25 U groups, with no noted benefit from the larger dose of 25 U. Average scar width on the treated side in the 15 U group was 1.1 mm, versus 2.2 mm on the placebo side.

The author also looked at the effect on patient perception using a modified Patient Observer Scar Assessment Scale, which showed improvement in the scale’s score with increasing doses of the active drug.

“… this study observed a reduction in inflammation for scarring of wounds treated with [botulinum neurotoxin type A]. The multipotency of [botulinum neurotoxin type A] on various cells may explain its role in the vascular, inflammatory, and proliferative stages of a wound healing. Furthermore, it is feasible that in early scar maturation stages [botulinum neurotoxin type A] has a role in the reorientation of collagen type 1 fiber. This seems a likely explanation for its effective use in delayed wound healing and even in the management of well-established scars (as reported by others),” the author writes.

Still, the study is too small to conclude that botulinum neurotoxin type A improves early facial scar management following facelift surgery, the author notes.

“Facets that could be investigated going forward could include modifying the injection protocol. For example, these results suggest that increasing the number of injections points might achieve a more uniform reduction in scar width,” according to the paper.

Other areas of future study include the optimal timing for neurotoxin application, as well as how different neurotoxin products might impact wound healing and scarring.

Disclosures:

The paper’s author declared no conflicts of interest and did not receive funding for the research.

References:

Chambers, Alexandra. Effects of Botulinum Toxin A Observed During Early Scar Formation Following Rhytidectomy: Controlled, Double-Blinded Pilot Study. Am J Cos Surg. Available online at https://journals.sagepub.com/doi/full/10.1177/0748806818794528 Accessed: May 8, 2019.