Efficacy of traction, using a clip-with-thread, for esophageal endoscopic submucosal dissection for esophageal lesions with fibrosis in an ex vivo pig training model

Novel beagle model of gastric local fibrotic target lesions for the evaluation and training of endoscopic techniques

BACKGROUND

Novel endoscopic techniques used in the treatment of gastric lesions with local submucosal fibrosis need preclinical evaluation and training due to safety limitations. Therefore, the purpose of our study was to establish an animal model of gastric local fibrotic target lesions and assess its feasibility in the evaluation and training of endoscopic techniques.

METHODS

In six experimental beagles, a 50% glucose solution was injected into three submucosal areas of the fundus, body, and antrum of the stomach to create gastric local fibrotic target lesions (experimental group). On post-injection day (PID) 7, the injection sites were assessed endoscopically to confirm the presence of submucosal fibrosis formation, and the dental floss clip traction assisted endoscopic submucosal dissection (DFC-ESD) procedure was performed on the gastric local fibrotic target lesions to confirm its feasibility after endoscopic observation. The normal gastric mucosa of six control beagles underwent the same procedure (control group). All the resected specimens were evaluated by histological examination.

RESULTS

All 12 beagles survived without postoperative adverse events. On PID 7, 16 ulcer changes were observed at the injection sites (16/18) under the endoscope, and endoscopic ultrasonography confirmed the local submucosal fibrosis formation in all ulcer lesions. The subsequent DFC-ESD was successfully performed on the 32 gastric target lesions, and the mean submucosal dissection time in the ulcer lesions was greater than that in the normal gastric mucosa (15.3 ± 5.6 vs. 6.8 ± 0.8 min; P < 0.001). There was no difference in rates of en bloc resection, severe hemorrhage, or perforation between the two groups. Histological analysis of the ulcer lesions showed the absence of epithelial or muscularis mucosae and extensive submucosal fibrous tissue proliferations compared with normal gastric mucosa. Overall, endoscopists had high satisfaction with the realism and feasibility of the animal model.

CONCLUSION

We developed a novel animal model of gastric local fibrotic target lesions to simulate difficult clinical situations, which strongly appeared to be suitable for the preclinical evaluation and learning of advanced endoscopic techniques.

Magnetic ring-assisted endoscopic submucosal dissection for gastric lesions with submucosal fibrosis: A preliminary study in beagle model

BACKGROUND

During endoscopic submucosal dissection (ESD) for gastric lesions with fibrosis, appropriate traction could provide clear submucosal dissection visualization to improve safety and efficiency of procedures. Therefore, the aim of this study was to evaluate the feasibility of magnetic ring-assisted ESD (MRA-ESD) for gastric fibrotic lesions.

METHOD

In the eight healthy beagles, 2-3 mL of 50% glucose solution was injected into submucosal layer of the stomach to induce gastric fibrotic lesions. A week after submucosal injection, two endoscopists at different levels performed MRA-ESD or standard ESD (S-ESD) for gastric simulated lesions, respectively. The magnetic traction system consisted of external handheld magnet and internal magnetic ring. The feasibility and procedure outcomes of the magnetic traction system were mainly evaluated.

RESULTS

Forty-eight gastric simulated lesions with ulceration were confirmed to have submucosal fibrosis formation by preoperative endoscopic ultrasonography. The magnetic traction system could be easily established, only took 1.57 min, and allowed excellent submucosal visualization. The total procedure time was significantly shorter in the MRA-ESD group than in the S-ESD group for both endoscopists (mean: 46.83 vs. 25.09 min, p < 0.001), and this difference was accentuated in non-skilled endoscopist. There was significant difference between two groups in bleeding and perforation rates. Histological analysis showed the depth of resected specimens was a little deeper around the fibrotic portion in the S-ESD group (p < 0.001).

CONCLUSION

The magnetic ring-assisted ESD technique may be an effective and safe treatment for gastric fibrotic lesions and may shorten the endoscopic learning curve for non-skilled endoscopists.

Rotatable Bi-Channel En Bloc Resection of Bladder Tumor for Non-Muscle-Invasive Bladder Cancer in an Ex Vivo Porcine Model

En bloc resection of bladder tumor (ERBT) is a promising alternative for non-muscle-invasive bladder cancer management. However, the tumor characteristics and surgeon's experience influence its application. Therefore, in this pilot study, we developed a technique called "rotatable bi-channel en bloc resection of bladder tumor (RBC-ERBT)" and assessed its feasibility, efficacy, and safety compared with those of conventional ERBT. In an ex vivo porcine bladder model, 160 bladder lesions of varying morphologies (exophytic and flat) and sizes (1 and 2 cm) were created and evenly distributed across different locations. A total of 160 procedures were performed, with the ERBT and RBC-ERBT group each exhibiting 80 lesions. RBC-ERBT had a significantly higher technical success rate than ERBT (98.8% vs. 77.5%) for exophytic and flat lesions of both sizes and dome lesions. The procedure time was significantly shorter in the RBC-ERBT group, particularly for flat lesions, lesions with a 2 cm diameter, and lesions located at the dome. RBC-ERBT had a significantly lower piecemeal resection rate than ERBT (0% vs. 18.8%). The incidence of perforation or detrusor muscle sampling did not differ between the groups. Compared with conventional ERBT, RBC-ERBT offered improved success rates, reduced resection times, and effective management of challenging lesions.