Outcome variability following nerve transfers for brachial plexus injuries: a cross-sectional observational study

Abstract Background Motor recovery after brachial plexus injury (BPI) varies depending on the type of nerve transfer procedure performed. This study aims to evaluate variability in motor recovery outcomes crucial for therapeutic planning and recovery estimation—specifically, elbow range of motion (ROM), biceps muscle activity, flexion, grip, and pinch strength—using different assessment tools. Methods After ethical clearance, a cross-sectional observation study was conducted on 30 subjects who met the Inclusion criteria. Ethical clearance was obtained from the Institutional Ethics Committee (Approval No.: NIMS/IEC/PT/2024/03). Subjects were stratified into three groups ( n = 10 each) based on the type of nerve transfer surgery: Oberlin 1, Oberlin 2, and intercostal nerve to musculocutaneous nerve (ICN–MCN). ROM was measured using a universal goniometer and the Pheezee device. Surface electromyography (sEMG) recorded biceps muscle activity. Elbow flexion strength was evaluated on the Medical Research Council (MRC) and Modified Medical Research Council (MMRC) scales. Grip and pinch strength were assessed using a hand-held dynamometer and a pinch gauge. Results The Oberlin 2 group showed superior elbow flexor strength and ROM compared to the other two groups. MMRC grading provided a more detailed stratification of strength recovery than MRC. The Pheezee device enabled simultaneous recording of ROM and surface EMG. The pinch strength of i–ii and i–iii digits is better in the Oberlin 1 group than in other groups on the affected side. ICN–MCN group had minimal recovery. Significant intergroup differences were noted in elbow ROM ( p < 0.01), MMT grades ( p = 0.0105), and MMRC grades ( p = 0.0193). sEMG amplitudes were highest in the Oberlin 2 group (889 ± 552 µV) and lowest in the ICN-MCN group (144 ± 142 µV). Conclusion Study results highlight the significant variability of outcomes based on the type of surgery. MMRC grading offers a more nuanced evaluation of recovery than MRC grading alone. The Pheezee device was useful for tracking ROM and EMG concurrently. The results of this study showed that the type of nerve transfer and the choice of appropriate instrument could affect the outcome. Choosing a suitable instrument for clinical correlation and documentation might further help plan stratified rehabilitation procedures.