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Botulinum Toxin Injection for Internal Rotation Contractures in Brachial Plexus Birth Palsy. A Minimum 5-Year
Bouke J Duijnisveld1, Marie S van Wijlen-Hempel, Simone Hogendoorn
1Departments of *Orthopaedics ‡Neurosurgery †Rehabilitation, Leiden University Medical Center, Leiden, The Netherlands.
Insights
Botulinum toxin A (BTX-A) injections in the subscapular muscle can improve external rotation and reduce the need for surgery in brachial plexus birth palsy patients. However, relapses occur in 67% of patients within 5 years.
Area of Science:
- Orthopedics
- Pediatric Surgery
- Neurology
Background:
- Brachial plexus birth palsy often causes shoulder internal rotation contractures due to muscle imbalance.
- Botulinum toxin A (BTX-A) is investigated as a treatment for these contractures.
Purpose of the Study:
- To evaluate the efficacy of BTX-A injections in the subscapular (SC) muscle.
- To assess the impact on shoulder external rotation and the requirement for tendon transfer surgery.
Main Methods:
- A prospective comparative study involved 15 patients receiving BTX-A injections and 67 historical controls.
- Patients received BTX-A (2 IU/kg) in the SC muscle under general anesthesia.
- Evaluated passive external rotation, need for surgery, glenohumeral deformity, and muscle degeneration.
Main Results:
- BTX-A group showed improved passive external rotation (from -1° to 32°) at 3 months, with 6 patients needing surgery versus 66 in the control group.
- At 5 years, 10 BTX-A patients required surgery, with a hazard ratio of 4.0 for relapse compared to controls.
- Less SC muscle degeneration was observed in good responders to BTX-A treatment.
Conclusions:
- BTX-A injections in the SC muscle can decrease internal rotation contractures and reduce the need for tendon transfer surgery.
- A significant relapse rate (67%) was observed at 5 years post-treatment.
- Identifying optimal patient candidates, considering factors like glenohumeral deformity and SC muscle degeneration, is crucial for future BTX-A treatment strategies.
Background:
Brachial plexus birth palsy is frequently associated with internal rotation contractures of the shoulder as a result of muscle imbalance. The purpose of this study is to assess the effect of botulinum toxin A (BTX-A) injection in the subscapular (SC) muscle on external rotation and the need for tendon transfer for external rotation of the shoulder.
Methods:
A prospective comparative study was performed including 15 consecutive patients treated with BTX-A and a historic control group of 67 patients with mean age 30 months (SD 10). The BTX-A injection (2 IU/kg body weight) was performed immediately following MRI under general anesthesia in the SC muscle. Passive external rotation, the need for tendon transfer surgery, glenohumeral deformity, and muscle degeneration were evaluated. The hazard ratio for no relapse of internal rotation contracture after BTX-A injection compared with no BTX-A injection was calculated.
Results:
In the BTX-A group, the passive external rotation in adduction increased from -1 degree (95% CI, -10 to 8) to 32 degrees (95% CI, 17-46) at 3 months and 6 patients were indicated for surgery compared with a decline from -2 degrees (95% CI, -7 to 3) to -11 degrees (95% CI, -17 to -6) in the control group with 66 indications for surgery. At 5 years of follow-up, 10 patients in the BTX-A group were indicated for surgery with a hazard ratio of 4.0 (95% CI, 1.9 to 8.4).
Conclusions:
BTX-A injection in the SC muscle of brachial plexus birth palsy patients can reduce internal rotation contractures and subsequently the need for tendon transfer surgery. At 5 years of follow-up a relapse was seen in 67% of the patients treated with BTX-A. Because at MRI less SC degeneration was found in the good responders on BTX-A treatment, this group seems to be the best target group. Further research is needed on patient selection for BTX-A injection including glenohumeral deformity, SC degeneration, as well as doses of BTX-A to be used.
Level Of Evidence:
Level II-prospective comparative study.
