Clinical Outcome of Lower Trapezius Muscle Transfer in Birth Brachial Plexus Palsy
Ramin Zargarbashi1, Nesa Milan, Hamid Rabiee
1From the Department of Orthopedic Surgery, Tehran University of Medical Sciences, Tehran, Iran (Zargarbashi, Rabiee, Baghbani, and Ebrahimian), the Department of Orthopedic Surgery, University of California San Francisco, San Francisco, CA (Milan and Wague), and the Department of Orthopedic Surgery, Mass General Hospital, Harvard Medical School, Boston, MA (Elhassan).
Insights
Lower trapezius muscle transfer significantly improves shoulder function in children with birth brachial plexus palsy (BBPP). This surgical technique enhances external rotation and abduction, offering a viable treatment for young patients.
Area of Science:
- Orthopedic Surgery
- Pediatric Rehabilitation
- Microsurgery
Background:
- Birth brachial plexus palsy (BBPP) impairs shoulder function, leading to external rotation and abduction limitations.
- Secondary shoulder dysplasia in BBPP patients further restricts shoulder mobility and function.
- Existing treatments include microsurgery, muscle transfer, and bony procedures, with recent success in adult lower trapezius transfers.
Purpose of the Study:
- To evaluate the efficacy of lower trapezius muscle transfer in treating BBPP in children under 7 years old.
- To assess functional shoulder improvements without allograft support in pediatric BBPP patients.
- To determine the safety and effectiveness of this procedure as an alternative for patients outside the ideal nerve transfer window.
Main Methods:
- A cohort of 15 BBPP patients (mean age 22 months) underwent lower trapezius muscle transfer to the infraspinatus footprint.
- Glenoid osteotomy was performed for patients with non-concentric joints prior to muscle transfer.
- Follow-up averaged 25 months, assessing shoulder external rotation, abduction, and Mallet scores.
Main Results:
- Significant improvements observed in hand-to-mouth, hand-to-neck, global shoulder abduction, and external rotation (P < 0.01).
- Total Mallet scores showed significant improvement (P < 0.01).
- No complications were reported post-procedure, indicating a safe intervention.
Conclusions:
- Lower trapezius muscle transfer effectively restores shoulder external rotation and abduction in young children with BBPP.
- The procedure demonstrates positive functional outcomes without adverse effects on daily activities.
- This surgical approach provides a valuable treatment option for BBPP patients unsuitable for nerve transfer.
Background:
Birth brachial plexus palsy (BBPP) can severely impair shoulder function by restricting external rotation and abduction, often leading to posterior subluxation or dislocation. Progressive shoulder dysplasia, a secondary condition of BBPP, further exacerbates functional disability by limiting shoulder function. Several techniques have been developed to address these challenges, including microsurgery, muscle transfer, and bony procedures. Recent reports on lower trapezius muscle transfer to the infraspinatus footprint demonstrate promising results in restoring shoulder biomechanics in adults. In this study, we aimed to treat patients younger than 7 years with BBPP through lower trapezius muscle transfer without allograft support.
Patients And Methods:
Between 2014 and 2018, 15 patients with BBPP and impaired shoulder external rotation and/or abduction (mean age, 22 months; range: 10 to 41 months) underwent lower trapezius muscle transfer surgery at our institution. A glenoid osteotomy was performed in patients without concentric joints, followed by the transfer of the lower trapezius muscle to the footprint of the infraspinatus. Patients were followed for an average of 25 months (range: 14 to 46 months). Outcomes assessed included shoulder external rotation, shoulder abduction, hand-to-mouth, hand-to-back, hand-to-neck, and Mallet scores.
Results:
Significant improvements were observed in hand-to-mouth, hand-to-neck, global shoulder abduction, global shoulder external rotation, and total Mallet scores ( P < 0.01). A nonsignificant decrease in hand-to-back was noted ( P > 0.05). Both shoulder external rotation and abduction increased significantly ( P < 0.01). No complications were reported after the muscle transfer procedure.
Discussion:
Lower trapezius muscle transfer to the infraspinatus footprint markedly improves shoulder external rotation and abduction in children younger than 7 years without adverse effects on daily activities. This procedure is an effective treatment option for patients who present outside the optimal window for nerve transfer.
Level Of Evidence:
Level IV; Case Series; Treatment Study.
