Postoperative management and rehabilitation after the supercharged end-to-side anterior interosseous nerve to ulnar motor nerve transfer: A report of 3 cases
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INTRODUCTION: Compressive ulnar neuropathy at the elbow is the second most common compressive neuropathy. Nerve transfers are used for severe ulnar neuropathies as a means of facilitating recovery. Hand therapy and rehabilitation after nerve transfers have not been extensively explored. PURPOSE OF THE STUDY: The aim of this repeated case study was to describe the responses, functional outcome, and neuromuscular health of three participants after the supercharged end-to-side (SETS) anterior interosseous nerve (AIN) to ulnar motor nerve transfer do describe the hand therapy and recovery of 3 cases reflecting different recovery potential mediators, trajectories, and outcomes. STUDY DESIGN: Repeated case study. METHODS: Three participants of similar age (76-80 years) that had severe ulnar neuropathy who underwent surgical treatment including a SETS AIN to ulnar motor nerve surgery were purposively selected from an ongoing clinical trial, based on their response to the surgical and the rehabilitation intervention (large, moderate, and small improvements). Clinical evaluations included measuring range of motion, strength testing, and clinical tests (ie, Egawa's sign) and, subjective assessment of rehabilitation adherence., Quick Disability of Arm, Shoulder and Hand and decomposition-based quantitative electromyography were performed at >23 months to evaluate patients. RESULTS: All the three participants completed the surgical and hand therapy interventions, demonstrating a variable course of recovery and functional outcomes. The Quick Disability of Arm, Shoulder and Hand scores (>23 months) for participants A, B, and C were 68, 30, and 18, respectively. The person with the least improvement had idiopathic Parkinson's disease, dyslipidemia, history of depression, and gout. Comparison across cases suggested that the comorbidities, longer time from neuropathy to the surgical intervention, and psychosocial barriers to exercise and rehabilitation adherence influenced the recovery process. The participants with the best outcomes demonstrated improvements in his lower motor neurons or motor unit counts (109 and 18 motor units in the abductor digiti minimi (ADM) and first dorsal interosseous, respectively) and motor unit stability (39.5% and 37.6% near-fiber jiggle in the ADM and first dorsal interosseous, respectively). The participant with moderate response to the interventions had a motor unit count of 93 for the ADM muscle. We were unable to determine motor unit counts and measurements from the participant with the poorest outcomes due to his physical limitations. CONCLUSIONS: SETS AIN to ulnar motor nerve followed by multimodal hand therapy provides measurable improvements in neurophysiology and function, although engagement in hand therapy and outcomes appear to be mediated by comorbid physical and psychosocial health.