Gastroesophageal Reflux after Stapler-assisted Mucosectomy in inverse-NOTES technique for Barretts Esophagus

• Applicants: Dr. Philip Müller; Dr. Daniel Steinemann
• Subject Area: General and Visceral Surgery
• Term: from 2016 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 322730519

Gastroesophageal reflux disease (GERD) leads to the replacement of squamous epithelium by intestinal mucosa in the distal esophagus (Barretts epithelium, BE). BE is a facultative precancerosis that can result in an invasive adenocarcinoma. Currently, close endoscopic surveillance is recommended for early detection of dysplasia or invasive cancer. The current treatment for dysplastic BE is endoscopic mucosal resection (EMR) or, alternatively, radiofrequency ablation. EMR makes histological analysis difficult due to resection of the specimen in pieces (piecemeal), but it is critical to assess the resection margins in cases with high-grade dysplasia or invasive cancer. A larger resection field, or even circular resection, presents a substantial risk for post- intervention strictures. Advanced BE with high-grade dysplasia that is not amenable to EMR is currently treated by esophagectomy, which is considered an invasive high-risk surgical procedure. There we devoloped a minimally invasive surgical technique for local mucosectomy for BE providing a circumferential en-bloc specimen suitable for further analysis. By a transgastric approach, a laparoscope is inserted into the stomach through the abdominal and gastric walls, and a pneumogastrium is established. In stapler-assisted mucosectomy (SAM) an intact, circumferential en-bloc specimen is obtained and stricture formation is prevented by avoiding open wound healing. We have demonstrated the feasibility of this novel method in a non-survival as well as in a survival porcine model. It has been demonstrate that the procedure is safe and that no strictures occur within 6 weeks. However, as patients with BE almost exclusively suffer from GERD the SAM procedure should be accompanied by antireflux surgery such as fundoplication. In SAM a circumferential mucosal resection with reconnection of the mucosa using circular staples is performed. This circumferential staple line could theoretically impair the function of the lesser esophageal sphincter. The experiment of this proposal will therefore evaluate the questions if SAM has an influence on GERD, if SAM could be combined with Nissen-fundoplication and if fundoplication is an effective antireflux procedure in combination with SAM. The successful implementation of SAM could change the way BE and GERD are treated. The combination of SAM and an antireflux procedure could allow patients with GERD and BE to be effectively treated long-term in a single-session, unlike current therapeutic options.

• DFG Programme: Research Grants