Consensus on the criteria for performance and assessment of technical quality of Supercharging End-to-Side nerve transfers: A Delphi study

Introduction Supercharging End-To-Side (SETS) nerve transfers are designed to provide intermediary innervation to muscles affected by proximal nerve lesions, preserving motor end-plates while awaiting parent nerve regeneration. However, no standardised surgical technique, anatomical nomenclature, or technical quality benchmark currently exists. This study aimed to establish expert-defined criteria for evaluating SETS transfer quality in Anterior Interosseous Nerve (AIN) to Motor Ulnar Nerve (MUN) procedures and to introduce a SETS performance grading matrix. Methods A three-stage Delphi process was conducted with international peripheral nerve experts. Two rounds of structured (round 1, N=37; round 2, N=23), questionnaire-based voting established consensus on quality-defining criteria for SETS AIN-to-MUN transfers (≥70% agreement). A final consensus round via panel discussion (N=9) and polling classified criteria as primary or secondary, confirmed key procedural steps defining the SETS technique, standardised anatomical nomenclature and ratified a proposed performance grading matrix. Results Experts were recruited via the Global Nerve Foundation based on clinical experience with the SETS AIN transfer. Consensus (100%) was achieved on anatomical nomenclature. Seven quality-defining criteria were established: Primary – tension at coaptation site, correct SETS position in motor fascicle group, absence of fascicle extrusion at inset, avoidance of recipient transection and adequate interfascicular epineurium dissection. Secondary criteria were size of the epineural window and suture depth placement. Common practices included use of 9′0 nylon sutures under magnification for neurorrhaphy, fibrin glue as an adjunct and immobilisation for a median of 21 days. Dissection of Guyon’s canal and intraoperative nerve stimulation were considered optional. Conclusions This Delphi study establishes the first expert consensus criteria for technical assessment of SETS AIN-to-MUN transfers, together with standardised terminology and a structured grading matrix. Consensus and participation data were comparable to published Delphi studies, supporting methodological validity; however, prospective clinical validation of the clinical efficacy of SETS must now follow.