Evaluating Elbow Flexion After Free Functional Gracilis Muscle Transfer in Adult Brachial Plexus Lnjury

• Study Overview This single-arm prospective clinical trial evaluates the efficacy of gracilis free functional muscle transfer (FFMT) for restoring elbow flexion in patients with late-presenting brachial plexus injuries (≥12 months post-injury) or failed prior reconstructive surgery. The gracilis muscle is the preferred donor due to its reliable vascular pedicle, adequate excursion, long motor nerve, and minimal donor-site morbidity .
• Primary Objective To assess postoperative elbow flexion strength using the British Medical Research Council (BMRC) grading system following gracilis FFMT neurotized by intercostal nerves (ICN) or spinal accessory nerve (SAN).

• Secondary Objectives

  • Evaluate active range of motion (AROM)
  • Measure time to first detectable muscle contraction and time to maximum power
  • Assess functional improvement via DASH scores
  • Compare outcomes between ICN and SAN neurotization groups
  • Compare outcomes between pediatric and adult patients
  • Document complications, particularly elbow flexion contracture

• Key Inclusion Criteria

  • Age 4-50 years
  • Elbow flexion loss or severe weakness for >12 months following brachial plexus injury (obstetric or traumatic)
  • Weak ipsilateral latissimus dorsi and pectoralis major (\<M3), unsuitable for local muscle transfer

• Key Exclusion Criteria

  • Age \<4 years (microvascular anastomosis feasibility concerns)
  • Age >50 years (diminished regenerative capacity)
  • Presentation within 12 months of injury
  • Reconstructable by local muscle or nerve transfer
  • Elbow joint stiffness or contracture
  • Uncontrolled comorbidities or inability to comply with rehabilitation
• Intervention

Gracilis FFMT harvested from the contralateral thigh with:

• **Neurotization:** ICNs (50%) or SAN (50%)
• **Vascular anastomosis:** Thoracoacromial artery (77%), thoracodorsal artery (13.6%), or subscapular artery (9.2%)

• **Muscle tensioning:** Elbow flexed 90-110° during inset

  • Primary Outcome Measure Postoperative elbow flexion power (BMRC grade) at 24-month follow-up
  • Secondary Outcome Measures
• Active range of motion (goniometry)
• Time to first clinical contraction
• Time to maximum power achievement
• DASH score

• Complication rate (flap loss, flexion contracture, scarring)

  • Sample Size 22 patients (17 male, 5 female; mean age 13.4±8.7 years)
  • Statistical Considerations
• Paired t-test for continuous outcomes
• Wilcoxon signed-rank test for non-parametric data
• Fisher's exact test for categorical comparisons

• Significance threshold: p\<0.05

  • Expected Outcomes Based on existing literature, 68-76% of patients achieve functionally useful elbow flexion (≥M3) following gracilis FFMT, with significant improvements in AROM and DASH scores . ICN neurotization may offer faster recovery to maximum power (approximately 9 months vs. 14 months for SAN) without compromising final strength .

    • Trial Registration:** Not reported (retrospective/prospective case series design)