Ulnar Nerve Injuries (Sunderland Grade V): A Simplified Classification System and Treatment Algorithm.

Area of Science:

• Neurosurgery
• Orthopedics
• Hand Surgery

Background:

• Ulnar nerve injuries present complex management challenges.
• Existing treatment strategies may not adequately address the varied injury sites.
• A standardized, zone-specific approach is needed for optimal outcomes.

Purpose of the Study:

• To introduce and validate a novel, zone-specific algorithm for managing ulnar nerve injuries (Sunderland grade 5).
• To assess the efficacy of nerve transfer techniques guided by internal nerve topography.
• To evaluate motor recovery and functional improvement in patients with distal ulnar nerve injuries.

Main Methods:

• A prospective observational study involving 110 patients with Sunderland grade 5 ulnar nerve injuries.
• Patients were categorized into four groups based on injury zone.
• Management involved tailored nerve transfer strategies; outcomes assessed using DASH score, grip strength, pinch strength, and MRC muscle power.

Main Results:

• Statistically significant improvements (P < 0.05) were observed in DASH scores, key pinch, and grip strength across all groups.
• High rates of motor recovery were achieved: 79.9% (Zone I), 93.9% (Zone II), and 84% (Zones III & IV) attained MRC grade >3 for the first dorsal interosseous muscle.
• The proposed algorithm demonstrated effectiveness in improving hand function regardless of injury zone.

Conclusions:

• The novel, zone-specific algorithm for managing Sunderland grade 5 ulnar nerve injuries is valid and effective.
• Nerve transfer techniques, informed by detailed nerve topography, yield significant functional recovery.
• This approach offers a promising strategy for improving outcomes in complex ulnar nerve injuries.