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)