IDDF2024-ABS-0218 Feasibility and efficacy of a magnetic countertraction system in colonic endoscopic submucosal dissection: an ex-vivo pilot study

<h3>Background</h3> Endoscopic submucosal dissection (ESD) is an advanced endoscopic procedure for treating superficial gastrointestinal neoplasms. Conventional ESD, utilizing single-channel endoscopes with a dedicated knife without countertraction, is a time-consuming and highly technically demanding procedure. We developed a novel magnetic countertraction system that consists of a flexible internal magnetic device (IDDF2024-ABS-0218 Figure 1. Magnetic countertraction system and experiment set up in the endoscopy centre of Prince of Wales hospital (a-b)), which could be deployed through the instrument channel of an endoscope, and a robot-assisted external magnetic source to provide traction (IDDF2024-ABS-0218 Figure 1. Magnetic countertraction system and experiment set up in the endoscopy centre of Prince of Wales hospital (c)). This pilot study aims to evaluate the feasibility of a magnetic anchor-guided ESD (MAG-ESD) with our system by comparing it with a conventional ESD (C-ESD). <h3>Methods</h3> This is an ex-vivo study using porcine colon models for ESD. Standard lesions of 3cm circumference were marked on the model over the gravity-dependent side. One expert and beginner endoscopist performed ESDs with and without a magnetic countertraction system. The distance between the external magnetic source and the internal magnetic device is fixed vertically 15cm apart. The primary outcome was procedure time. Secondary outcomes included completeness of en-bloc resection, intra-procedure muscle damage and full-thickness perforation. The NASA Task Load Index (TLX) was used to assess the workload of the endoscopists in each procedure. <h3>Results</h3> Two endoscopists each performed 4 ESD (2 MAG-ESD and 2 C-ESD), totalling 8 procedures (IDDF2024-ABS-0218 Figure 2. Resected specimens of 8 ESD procedures). Procedure time was shorter for MAG-ESD, with a trend towards statistical significance (26.30min vs 32.61min, <i>P</i>=0.097) (IDDF2024-ABS-0218 Table 1). Magnetic retraction establishment time was 2.00±0.85 min, and traction was stable during procedures (IDDF2024-ABS-0218 Figure 3. Magnetic retraction establishment and traction performance during procedure). Complete en-bloc resection was achieved in all procedures. Due to the small sample size, no significant difference was identified in the rate of muscle injury and perforation. A trend towards lower procedural workload was detected in the MAG-ESD procedures, with the NASA-TLX score of 27.3 vs 41.5 (<i>P</i>=0.192) (IDDF2024-ABS-0218 Table 2). <h3>Conclusions</h3> In the current pilot study, MAG-ESD was associated with a trend towards shorter procedural time and less workload for the endoscopists. Further study is required to confirm the benefit of a magnetic countertraction system during ESD.