Ultrasound and clinical outcomes of vascularized ulnar nerve transposition

Ulnar nerve entrapment at the elbow is common but results of ulnar nerve transposition remained uncertain. Chronic nerve ischemia is implicated in the syndrome's pathophysiology, and surgical interventions aim to mitigate related damage. The main hypothesis is that preserving the vascular system during ulnar nerve transposition helps prevent ischemic damage and improves clinical outcomes.

Thirty five patients were included and divided into two groups: 'Vascularized Ulnar Nerve' (UNV+) and 'Non-vascularized Ulnar Nerve' (UNV-). They underwent subcutaneous anterior transposition of the ulnar nerve. Preoperative and postoperative clinical assessment was made using: Bishop score, Visual Analog Scale, Levine-Katz survey, Functional Status Scale, and QuickDash Score. Post operative nerve extrinsic vascularization was assessed with ultrasound.

Results after a mean 19.2-month follow-up show superior clinical outcomes, including Bishop and Levine-Katz scores, in the 'Vascularized Ulnar Nerve' group. Despite longer operative times (47 min in UNV + vs. 33 min in UNV-), no vascular complications occurred, supporting the hypothesis that preserving extrinsic vascularization enhances results. Extrinsic vascularization of the ulnar nerve could be continuously observed from proximal to distal in all patients in the UNV+ group. In 4 out of 15 cases in the UNV- group, vascularization was observed along the entire length of the nerve.

Ultrasound assessments indicated improved nerve characteristics in the vascularized ulnar nerve group, reinforcing the study's main conclusion: preserving the extrinsic vascular system during ulnar nerve transposition was associated to better clinical outcomes. However, the study acknowledges limitations, urging further research with larger cohorts and electromyographic evaluation for a comprehensive understanding.

Case series Therapeutic study.