A Novel Ex-Vivo Snare Tip Soft Coagulation Model for Deliberate Self-Practice and Assessing Endoscopic Tip-Control Competency: The HAM-2 Study

Background and Aims: Tip-control is fundamental to advanced endoscopic procedures but lacks objective assessment tools. We aimed to (1) validate an ex-vivo snare tip soft coagulation (STSC) model (HAM-2) by assessing its ability to stratify endoscopists by experience (2) evaluate its efficacy in improving tip-control following structured training; and (3) identify baseline predictors of training-related improvement. Methods: In this prospective pilot validation study (single-centre, single-arm, pre/post design), thirteen endoscopists (1 expert, 7 fellows, 5 trainees) performed STSC along 4 standardized 3D-printed shapes on a cooked-ham model. Participants underwent pre-training assessment, two unsupervised structured self-practice sessions (8 shapes), and post-training assessment. Seven blinded raters (three independent raters per video) evaluated video recordings for their subjective impression of tip-control and determined objective metrics (number of correct and incorrect hits) using an online tool. Predictors of improvement were analysed using generalized linear mixed models. Results: 13 endoscopists performed 104 STSC procedures. At baseline, the expert outperformed fellows and trainees in subjective tip-control (95.3 vs. 59.7 vs. 56.3, p<0.001), speed (40.6 vs. 23.6 vs. 19.7 mm/min, p=0.002) and accuracy (98.1% vs. 92.7% vs. 90.6%, p=0.003). Considering the overall cohort subjective tip-control improved by 12.3 (95% CI 6.9–17.7, p<0.001), speed by 5.5mm/min (3.1–7.9, p<0.001), and hit frequency by 6.1hits/min (3.7–8.5, p<0.001) post-training. Accuracy did not improve significantly (+1.3%, p=0.085). Lower endoscopist baseline accuracy and speed independently predicted greater improvement in subjective tip-control. Conclusions: In this single-centre, single-expert pilot, the HAM-2 model stratified endoscopists by experience (exploratory) and, through self-practice on the model, yielded measurable improvements in tip control following repeated practice. HAM-2 offers a low-cost, reproducible platform for structured self-practice and task-specific performance measurement.