Botulinum Toxin Injection After Sternotomies to Improve Scar Aspect and Impact

NCT ID: NCT07013240

Last Updated: 2025-06-10

Basic Information

• Recruitment Status: NOT_YET_RECRUITING
• Clinical Phase: PHASE3
• Total Enrollment: 50 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2025-07-05
• Study Completion Date: 2027-02-28

Brief Summary

Sternotomy scars, which are localized in a high-tension area are often dystrophic, hypertrophic or keloidal, and can be difficult to accept to patients who already endured a heavy intervention with high psychologic impact. The investigators wish to evaluate immediate post-surgical injection of botulinum toxin to improve scar aspect and impact. A randomized, placebo-controlled, split-scar clinical trial will determine the improvement of scar aspects assessed by standardized scores (SBSES, POSAS), patient satisfaction and tolerance.

Detailed Description

Adult wound healing does not restore the original skin architecture, and results in fibrotic scars. Specifically in high-tension areas and due to activation of fibrogenesis pathways, wound healing processes can lead to pathological scarring, hypertrophic scars, or keloids. The anterior thoracic region is one the body area suggested to the highest tensions, and sternotomies are performed perpendicularly to the lines of skin tension. Therefore, sternotomy scars are often dystrophic, inaesthetic and fibrous, or even hypertrophic. Depending on geographical distribution, sternotomy scars are found hypertrophic in 10 % to more than 50 % of cases. Aesthetic impact or related symptoms such as pruritus and pain impair psychological state and alter quality of life of these patients who endured a frequently difficult to handle surgical procedure.

Botulinum toxin type A is a neurotoxin derived from Clostridium botulinum culture. Through inhibition of pre-synaptic acetylcholine release, it induces local muscle paralysis that is reversible in a few months. Its interest is widely described in urology and neurology. Its dermatologic uses include the cosmetic purpose to reduce face wrinkles and the functional purpose to reduce hyperhidrosis. Its safety is well established. It has been proposed in the prevention and treatment of hypertrophic scars and keloids, and has been shown to reduce TGFß1, a main actor of fibrogenesis and pathological scarring. Through reduction of myofibroblastic differentiation, it downregulates mechanisms leading to dystrophic scars.

It was proposed in the improve scar aspect after surgical procedures, and early post-operative local injections showed efficacy in thyroidectomies, mammoplasties, or face surgeries to enhance scar aspect. Regarding sternotomy, a single study in China with a small sample (17 patients) studied post-operative injections (8 to 14 days after) of botulinum toxin. This split-scar study reported significant improvement of Vancouver Scar Scale, scar width and patient satisfaction in the treated site, at 6 months.

The authors aim to evaluate immediate post-operative botulinum toxin after sternotomies, to improve scar aspect through standardized scores (Stony Brook Scar Evaluation Scale, Patient and Observer Scar Assessment Scale) and impact through patient satisfaction at 6 and 18 months. The double-blind randomized placebo-controlled trial will be conducted in split-scar method, with administration for each patient of treatment (botulinum toxin) or placebo (saline) in the upper or lower part of scar, according to randomization.

Each patient will serve as its own control and will be evaluated for up to 18 months by a dermatological team, following standardized monitoring, including objective and subjective scores, as well as tolerance data.

Conditions

Sternotomy Closure,Open Heart Surgery

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: PREVENTION
• Blinding Strategy: QUADRUPLE

Study Groups

Upper Arm

Intervention (botulinum toxin) in the upper half of the scar and placebo in the lower half

Group Type: EXPERIMENTAL

Botulinum toxin injection

Intervention Type: DRUG

Intervention will be made immediately after surgery, still under general anesthesia, by the cardiac surgeon, after suture.

Each patient will receive (either in the lower part or the upper part of the scar according to randomization) 50 international units (IU) of type A botulinum toxin (Botox®, Allergan aesthetics) diluted in 1 mL of saline to enable injection of 5 IU at each point, every centimeter, at 1 cm of each scar side.

An equivalent volume of saline will be injected under the same modalities in the other part of the scar.

Lower Arm

Intervention (botulinum toxin) in the lower half of the scar, and placebo in the upper half.

Group Type: EXPERIMENTAL

Botulinum toxin injection

Intervention Type: DRUG

Intervention will be made immediately after surgery, still under general anesthesia, by the cardiac surgeon, after suture.

Each patient will receive (either in the lower part or the upper part of the scar according to randomization) 50 international units (IU) of type A botulinum toxin (Botox®, Allergan aesthetics) diluted in 1 mL of saline to enable injection of 5 IU at each point, every centimeter, at 1 cm of each scar side.

An equivalent volume of saline will be injected under the same modalities in the other part of the scar.

Interventions

Botulinum toxin injection

Intervention will be made immediately after surgery, still under general anesthesia, by the cardiac surgeon, after suture.

Each patient will receive (either in the lower part or the upper part of the scar according to randomization) 50 international units (IU) of type A botulinum toxin (Botox®, Allergan aesthetics) diluted in 1 mL of saline to enable injection of 5 IU at each point, every centimeter, at 1 cm of each scar side.

An equivalent volume of saline will be injected under the same modalities in the other part of the scar.

Intervention Type: DRUG

Eligibility Criteria

Inclusion Criteria

• Patient aged 18 years or older
• Scheduled sternotomy at Bordeaux University Hospital within the next 4 months
• Person affiliated with or benefiting from a social security system
• Patient able to attend follow-up visits required by the study
• Free, informed, and written consent signed by the participant or an impartial witness (in case the participant is unable to write) and the investigator (no later than the day of inclusion)

Exclusion Criteria

• Known allergy to botulinum toxin type A or any excipient in BOTOX® (human albumin, sodium chloride)
• Neuromuscular transmission disorder (myasthenia gravis or Lambert-Eaton syndrome)
• Motor peripheral neuropathy (such as amyotrophic lateral sclerosis or motor neuropathy)
• Infection at the injection sites
• Pregnancy or breastfeeding
• Person under protection measures

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

University Hospital, Bordeaux

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Robin ZAGALA, MD

Role: PRINCIPAL_INVESTIGATOR

University Hospital, Bordeaux

Locations

Centre Hospitalier Universitaire de Bordeaux

Bordeaux, , France

Countries

France

Central Contacts

Robin ZAGALA, MD

Role: CONTACT

robin.zagala@chu-bordeaux.fr

+335 56 79 56 79

Claire BAZIN

Role: CONTACT

bazin.claire@chu-bordeaux.fr

+335 57 82 25 09

Facility Contacts

Robin ZAGALA, MD

Role: primary

robin.zagala@chu-bordeaux.fr

+335 56 79 56 79

Claire BAZIN

Role: backup

bazin.claire@chu-bordeaux.fr

+335 57 82 25 21

References

Singer AJ, Arora B, Dagum A, Valentine S, Hollander JE. Development and validation of a novel scar evaluation scale. Plast Reconstr Surg. 2007 Dec;120(7):1892-1897. doi: 10.1097/01.prs.0000287275.15511.10.

Reference Type: BACKGROUND

PMID: 18090752 (View on PubMed)

Other Identifiers

CHUBX 2024/31

Identifier Type: -

Identifier Source: org_study_id