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Validity evidence for an objective scoring tool for endoscopic tip control during snare-tip soft coagulation (with
Lobke Desomer1, Tamás Tornai2, Pieter Jan Poortmans3
1Department of Gastroenterology and Hepatology, AZ Delta Roeselare, Roeselare, Belgium; Department of Gastroenterology and Hepatology, University Hospital Ghent, Ghent, Belgium; Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium.
Background And Aims:
Tip control (TC) is a core endoscopic skill, yet objective and practical in vivo assessment tools are lacking. We developed and gathered validity evidence for a scoring method using snare-tip soft coagulation (STSC) of the post-EMR defect margin as a standardized task.
Methods:
A prospective, single-center observational study of consecutive patients undergoing EMR for large (≥20 mm) nonpedunculated colorectal polyps was conducted. Live or video observers used a web tool to classify STSC applications as correct ("on-margin") or incorrect. Outcomes were accuracy, speed (correct hits/min), z-standardized composite score (z_accuracy + z_speed = performance index), and rater subjective impression. Group differences (experts >500 EMRs vs trainees <50 EMRs) were estimated with generalized linear mixed-effects models, with random intercepts for endoscopist, observer, and procedure. Interrater reliability (intraclass coefficient [2,k]) was calculated.
Results:
Sixty-eight procedures performed by 14 endoscopists were scored by 19 observers (170 ratings; median 2 per procedure; IQR, 1-3). Experts (n = 3) outperformed trainees (n = 11) for accuracy (adjusted mean, 90.0% vs 81.2%; adjusted mean difference [AMD], +8.9 percentage points [95% CI, 4.6-12.9]; P < .001) and speed (13.3 correct hits/min [95% CI, 11.0-15.6] vs 9.7 [95% CI, 8.0-11.4]; AMD, +3.6 correct hits/min [95% CI, 0.9-6.3]; P = .01). The performance index for experts was significantly higher than for trainees (AMD, +1.4 [95% CI, 0.7-2.2]; P < .001). Overall impression scores also favored experts (AMD, +1.0 points on 0-10 scale [95% CI, 0.5-1.6]; P < .001). ICC(2,k) for overall impression and accuracy was excellent (ICC[2,k] = 0.98 and 0.97, respectively). Convergent validity was demonstrated by significant associations between overall impression and both accuracy (β = 0.8 per 10 percentage points [95% CI, 0.7-1.0]; P < .001) and speed (β= 0.7 per 10 hits/min [95% CI, 0.4-1.0]; P < .001).
Conclusions:
A simple, in vivo, procedure-level score captured during routine STSC provided an objective measure of endoscopic tip TC, separating experts from trainees.
