Developing a Consensus-Based Core Set of Outcome Measures for Ulnar Nerve Surgery: A Delphi Study With Focus on the Supercharged End-to-Side Anterior Interosseous Nerve to Ulnar Nerve Transfer

Purpose: The supercharged end-to-side (SETS) anterior interosseous to ulnar nerve transfer is increasingly used to augment intrinsic muscle recovery in patients with severe ulnar neuropathy. However, there is a lack of standardized outcome measures to evaluate the effectiveness of this procedure. This study aimed to develop a consensus-based core set of outcome measures applicable to ulnar nerve surgery, with a specific focus on the SETS transfer. Methods: A two-round modified Delphi process was conducted involving 15 multidisciplinary experts in hand surgery and upper limb rehabilitation. The initial survey was informed by a comprehensive literature review and expert opinion. Participants ranked outcome domains and corresponding measurement tools based on their relevance in both clinical and research settings. Consensus was defined as ≥75% agreement. A second-round survey was conducted to refine the results and focus specifically on outcomes applicable to SETS procedures. Results: In Round 1, experts reached consensus on several key domains including motor function, functional ability, quality of life, pain, dexterity, and sensory evaluation. In Round 2, a refined core outcome set for SETS procedures was established. Lateral pinch strength and daily living function self-assessment were prioritized across both settings. Validated tools endorsed included the Patient-Rated Ulnar Nerve Evaluation, Short Form-12, visual analog scale, nine-hole peg test, and two-point discrimination. Conclusions: This Delphi study established a consensus-based core outcome set for evaluating surgical outcomes following ulnar nerve reconstruction, with specific application to SETS procedures. The proposed framework integrates patient-reported and clinician-rated measures and may support standardization in future research and clinical practice. Clinical relevance: The lack of standardized outcomes for ulnar nerve transfers limits cross-study comparisons and evidence synthesis. This study provides a structured outcome set to support consistent evaluation and improve decision making in patients undergoing SETS or related procedures.