Permanent hand motor deficit and failure of elbow flexion recovery following Oberlin nerve transfer. A retrospective case series

Introduction: The Oberlin nerve transfer is widely used to restore elbow flexion after brachial plexus injury. However, donor-site morbidity, particularly permanent motor deficit, has been rarely reported. This retrospective case series describes permanent donor-site morbidity following the Oberlin procedure and explores its association with poor elbow flexion outcomes. Methods: Nine patients (mean age, 38 years) with upper-type brachial plexus paralysis, including seven C5–C8 injuries, were referred to a tertiary centre after undergoing a primary Oberlin transfer at external institutions. All patients described immediate hand paralysis and/or failure of elbow flexion recovery after the surgery. Patients were reassessed at a mean follow-up of 27 months (range, 9–48). Outcome measures included assessment of hand motor deficits, grip strength and elbow flexion recovery using the Medical Research Council scale. Results: Six of nine patients failed to achieve functional elbow flexion (M0, n = 4; M2, n = 2). Eight patients had ulnar nerve involvement, most commonly paralysis of the first dorsal interosseous muscle ( n = 7) and clawing deformity ( n = 6). One patient exhibited isolated anterior interosseous nerve paralysis. Mean grip strength was markedly reduced, averaging 14 kg compared with reported normal values of 30–50 kg. Conclusions: The frequent association between irreversible hand weakness and unsatisfactory elbow flexion recovery highlights the limited functional reserve of donor nerves in selected clinical scenarios. These findings emphasize careful patient selection and microsurgical expertise in Oberlin transfers. Level of evidence: IV