Assistant skill in gastric endoscopic submucosal dissection using a clutch cutter

Background: A clutch cutter is a scissor-type knife used in endoscopic submucosal dissection (ESD) for gastrointestinal tract tumors. The assistant during the ESD using a clutch cutter (ESD-C) needs to rotate the device and grasp the target tissue appropriately; therefore, the assistant's skill may affect the technical outcomes of ESD-C.

Aim: To determine how assistant skill level affected the technical outcomes of gastric ESD-C using an ex vivo porcine training model.

Methods: In this pilot study, mock lesions of 15-30 mm in diameter were created in the middle or lower third of the porcine stomach. A total of 32 ESD-C procedures were performed by 16 trainees. Each trainee operator performed two ESD-C procedures; one ESD-C was assisted by an expert (ESD-C-E), and the other was assisted by a non-expert (ESD-C-NE). The total procedure time of the ESD was set as the primary outcome, and en bloc resection rate, complete procedure rate, perforation rate, and each procedure time/speed for mucosal incision or submucosal dissection were set as the secondary outcomes. In addition, we investigated factors associated with the difficulty of ESD including incompletion of ESD procedure, a long procedure time (≥ 20 min) or intraoperative perforation.

Results: The median total procedure time of the ESD-C-E was significantly shorter than that of the ESD-C-NE (12.9 min vs 21.9 min, P = 0.001). The en bloc resection rate was 100% in both groups. Complete resection rates of the ESD-C-E and ESD-C-NE groups were 100% and 93.8%, respectively. No intraoperative perforation was observed in both groups. In the multivariate analysis, assistant skill was significantly associated with the difficulty of ESD, with the highest odds ratio of 16.5.

Conclusion: Assistance by an expert is an important factor when trainees perform ESD-C procedures.