Distal nerve transfers for ulnar nerve reinnervation and hand function restoration

Area of Science:

• Orthopedics
• Neurosurgery
• Hand Surgery

Background:

• Ulnar nerve injuries cause severe hand dysfunction, impacting grip, pinch, and overall quality of life.
• Conventional repair and grafting methods have limitations in restoring intrinsic hand muscle function.
• Distal nerve transfers offer a potential solution by reducing nerve regeneration distance.

Purpose of the Study:

• To evaluate the efficacy of distal anterior interosseous nerve to deep motor branch of the ulnar nerve (AIN-to-UN-DMB) transfer.
• To assess the restoration of intrinsic hand function after proximal ulnar nerve injuries.
• To determine the impact on patient-reported quality of life.

Main Methods:

• Prospective evaluation of 12 patients undergoing distal AIN-to-UN-DMB transfer for proximal ulnar nerve injuries.
• Assessment at 24 months postoperatively using British Medical Research Council (BMRC) scale for muscle strength, Egawa's sign, and dynamometric grasp/pinch strength.
• Quality of life measured using the Patient-Reported Neuromuscular Skeletal Questionnaire (PNSQoL).

Main Results:

• Significant improvement in intrinsic muscle strength (M4/M3 grades achieved), compared to M0 preoperatively.
• Marked increase in grasp strength (42.3% to 82.5%) and pinch strength (37.4% to 80.5%) of the contralateral hand.
• 87.5% satisfactory functional recovery, with significant improvement in PNSQoL scores (47.7 to 74.4, p < 0.001).

Conclusions:

• Distal AIN-to-UN-DMB transfer effectively restores intrinsic hand function after proximal ulnar nerve injuries.
• The procedure leads to substantial gains in grasp and pinch strength.
• Significant improvements in patient-reported quality of life make this an effective reconstructive option.