Nonexposed wall-inversion surgery as a novel local resection method for neoplasms in the gastrointestinal tract.

Nonexposed wall-inversion surgery was invented for the treatment of node-negative gastrointestinal tumors that are difficult to be resected using the endoluminal approach alone. The advantages of this surgery include 1. full-thickness resection procedure of gastrointestinal wall with minimum necessary tumor-negative margins and 2. less risk of bacterial contamination and tumor seeding into the abdominal cavity. We conducted a PubMed search to select relevant articles published until the end of October 2019 for pooled case analyses using the keyword "nonexposed wall-inversion surgery," Based on our search, we enrolled the data of 88 gastric lesions and 1 duodenal lesion retrieved from 7 case report articles and 4 original articles of clinical cases. The gastric lesions consisted of 59 gastrointestinal stromal tumors, 7 ectopic pancreases, 5 leiomyomas, 3 early gastric cancers, and 14 others, with a mean maximal tumor diameter of 25.0 mm. In 5 lesions (5.7%), intraoperative perforation was performed, and 2 lesions (2.3%) were retrieved by the transabdominal route. All 4 major postoperative complications (4.5%) were managed without resurgical interventions. The duodenal case, neuroendocrine tumor, measuring 13 mm in size, was curatively resected without complications. Nonexposed wall-inversion surgery appears to be an acceptable treatment for node-negative gastric and duodenal tumors; however, further accumulation of cases is necessary to confirm the feasibility.