Fixation of biomaterial to metallic stent and fixation of stents after circular endoscopic dissection in the esophagus on an animal model

Abstract

Introduction: Complete circular endoscopic (submucosal) resection (CER) performed using the endoscopic submucosal dissection (ESD) technique is burdened with a high incidence of post-operative strictures in the esophagus. The most effective method of preventing them is not known so far; one of the possible methods is to prevent these strictures directly at the site of their formation by covering the defect with a stent. The aim of the study was to find a way to fix a selected biomaterial to a stent, and subsequently, to fix the stent at the CER site to prevent esophageal strictures in an animal model.
Method: Miniature piglets from the Czech Academy of Sciences’ breeding unit in Libechov (N=10) were used. Endoscopy was performed using a single- channel endoscope. First, we made two circular mucosal cuts spaced 5 cm apart in the middle esophagus and we performed the CER between them using the endoscopic submucosal dissection technique. After that, we covered the defect with a stent coated with biomaterial (Xe-Derma®) while we tried to prevent stent migration into the stomach. For stent fixation, we tested endo-clips (N=3), the Apollo endoscopic system (N=1) and the suspension technique using two polyamide threads (N=6) anchored in the nasal septum. We performed a control endoscopy, stent removal and subsequent autopsy after 1−2 weeks.
Results: All procedures were completed successfully without serious complications or deaths. Although stents covered with Xe-Derma® were applied to the entire resection area, one case of mediastinitis and one paraesophageal abscess were found during autopsy, most likely due to microperforations caused during the procedure. Histological analysis showed that after contact with the biomaterial, re-epithelisation took place within one week of application to the resection area. Stent migration occurred in each case when the stent was attached to the esophageal wall by endo-clips or with the endoscopic suture system (Apollo). There was no stent dislocation in the cases where the stent was suspended by two polyamide threads.
Conclusion: We developed a technique of fixing biomaterial to the surface of metallic stents which we used to prevent the formation of esophageal strictures after CER. Distal suspension fixation of the stent with a polyamide thread proved to be the most effective, while fixations by endo-clips or with the endoscopic suture system were ineffective.