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Botulinum Toxin Injection After Sternotomies to Improve Scar Aspect and Impact

Immediate Post-surgical Botulinum Toxin Injections to Prevent Dystrophic Scars After Sternotomy : a Placebo-controlled Randomized Clinical Trial

Status
Not yet recruiting
Phases
Phase 3
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07013240
Acronym
BotuCiSter
Enrollment
50
Registered
2025-06-10
Start date
2025-07-05
Completion date
2027-02-28
Last updated
2025-06-10

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Sternotomy Closure,Open Heart Surgery

Keywords

scar, keloid, botulinum toxin, sternotomy

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.

Interventions

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.

Sponsors

University Hospital, Bordeaux
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)

Masking description

Only the Methodology Center and the Bordeaux University Hospital Pharmacy will have access to the correspondence list between the patient's number, the type of product and the area treated (lower or upper part of the scar). At no time during the study will investigators or patients have access to this list.

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

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

Design outcomes

Primary

MeasureTime frameDescription
Evaluation of Stony Brooke Scar Scale scoreMonth 6The Stony Brook Scar Evaluation Scale (SBSES) was developed by Singer et al. in 2007. It is based on five scar indicators: width, elevation or depression, color, suture or staple marks, and overall appearance.Each indicator is assigned a score between 0 and 5 points. These scores are totaled to obtain the final score between 0 and 5 points. This score will be determined for each half of scar (superior part and inferior part).

Secondary

MeasureTime frameDescription
Evaluation of scar with POSAS : observer scaleMonth 3, month 6, month 12 and month 18The observer's POSAS scale comprises six parameters (vascularity, pigmentation, thickness, relief, elasticity and surface). Each parameter is rated on a scale from 1 (normal skin) to 10 (worst scar imaginable). The sum of the six parameters constitutes the observer's total POSAS score scale . In addition, a general opinion is scored from 1 to 10. All parameters should preferably be compared to normal skin on a comparable a comparable anatomical region. This scale will be determined for each half of scar (superior part and inferior part).
Evaluation of scar with The Physician's Global Assesment (PGA)Month 3, Month 6, Month 12 and Month 18The Physician's Global Assesment (PGA) evaluates the scar based on whether it is considered an Invisible scar ; a Scar as fine as a pencil line, of a color similar to the adjacent skin ; a Visible scar, little infiltrated or flat, discreetly colored ; a Widened and infiltrated scar, visible suture lines, of a color contrasting with the skin ; a Hypertrophic scar, raised, hypervascularized or very hyperpigmented ; a Keloid. This evaluation will be determined for each half of scar (superior part and inferior part).
Measure of scar width in millimetersMonth 3, month 6, month 12 and month 18
Evaluation of scar with POSAS : Patient scaleMonth 3, Month 6, Month 12 and Month 18The patient's POSAS scale comprises six parameters (pain, itching, color, stiffness, thickness and irregularity). Each parameter is rated on a scale from 1 (normal skin) to 10 (worst scar imaginable). In addition, a general opinion is scored from 1 to 10. The sum of all these parameters constitutes the patient's total POSAS score scale. All parameters should preferably be compared to normal skin on a comparable a comparable anatomical region. This evaluation will be determined for each half of scar (superior part and inferior part).
Satisfaction numerical scaleMonth 3, Month 6, Month 12 and Month 18Scar satisfaction is rated on a scale from 0 (not at all satisfied) to 10 (extremely satisfied). This scale will be determined for each half of scar (superior part and inferior part).
Evaluation of Stony Brooke Scar Scale scoreMonth 3, Month 12 and Month 18The Stony Brook Scar Evaluation Scale (SBSES) was developed by Singer et al. in 2007. It is based on five scar indicators: width, elevation or depression, color, suture or staple marks, and overall appearance. Each indicator is assigned a score between 0 and 1 point. These scores are totaled to obtain the final score between 0 and 5 points. This scale will be determined for each half of scar (superior part and inferior part).

Countries

France

Contacts

Primary ContactRobin ZAGALA, MD
robin.zagala@chu-bordeaux.fr+335 56 79 56 79
Backup ContactClaire BAZIN
bazin.claire@chu-bordeaux.fr+335 57 82 25 09

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026