The hand diagram: A novel outcome measure following supercharged end-to-side anterior interosseous nerve to ulnar nerve transfer in severe compressive ulnar neuropathy.

BACKGROUND: With advances in the surgical management for severe ulnar neuropathy with the introduction of the super charged-end-to-side (SETS) anterior interosseous nerve (AIN) to ulnar nerve transfer, a simple and reliable outcome measure is required. There is currently not "one" standardized outcome measure used to represent and compare results.

PURPOSE: To present the abduction hand diagram as a "novel", reproducible, and simple outcome measure for patients with severe ulnar neuropathy.

STUDY DESIGN: Retrospective case series.

METHODS: Nine patients with severe entrapment/compressive ulnar neuropathy at the elbow were reviewed. Clinical parameters included preoperative and postoperative abduction tracings, Medical Research Grade (MRC) muscle strength, key pinch strength, Disability of the Hand Arm and Shoulder (DASH) score, and crossed finger test. Electrodiagnostic data included change in compound muscle action potentials (CMAP) amplitude of the first dorsal interosseous (FDI), and abductor digiti minimi (ADM). Summary statistics were used for demographic and clinical data.

RESULTS: Average follow-up was 22.8 ± 9.3 months. At 18-months of follow up, 44% had ADM MRC grade 3 strength or higher, mean key pinch strength improved to 72 ± 19.3%, and mean DASH was 33 ± 28.7. There was a mean increase of 16.7 ± 9.1 mm and 31.5 ± 12 mm in total and summed hand abduction tracing measurements respectively.

CONCLUSIONS: Hand abduction tracings are a quantitative outcome measure to follow recovery over time for intrinsic hand function and can be used in patients with severe ulnar neuropathy following surgical intervention.