title: Submucosal endoscopy with mucosal resection (SEMR): a new hybrid technique of endoscopic submucosal balloon dissection in the porcine rectosigmoid colon.
abstract: BACKGROUND
  We developed a technique, submucosal endoscopy with mucosal resection (SEMR) intended to make endoscopic submucosal dissection easier and safer. With this technique, the submucosal layer is balloon dissected in lieu of electrosurgical knife dissection. The aim of this study was to further evaluate SEMR in the porcine rectum and colon.
  
  
  METHODS
  Targeted sites in the rectum and the distal colon were marked by spot coagulation. Submucosal fluid cushions (SFC) were created followed by a circumferential mucosal incision. After isolation of the targeted mucosa, balloon dissection was initiated. The balloon catheter was inserted deep into SFC and the inflated balloon repeatedly pulled back toward the endoscope tip to disrupt the submucosa. Residual strands of submucosa were cut. Dissection difficulty scores (DDS) were used using a visual analogue scale ranging from 0 to 5 (failed). The entire study period was divided into three periods (first period, pigs 1-10; second period, pigs 11-20; third period, pigs 21-30).
  
  
  RESULTS
  Sixty lesions in 30 pigs were resected using SEMR. The en block resection rate was 95%. There were three incomplete resections, two as a result of an errant site location and one as a result of a floppy prototype balloon catheter tip. The median resected size, procedure time, and DDS were 6.0 cm, 25 min, and 1. All three failed cases occurred in first period. The procedure time in third period was significantly shorter than the second period (P = 0.0017). The DDS in first period was significantly higher than the second (P = 0.0024) and third (P = 0.0155) periods. Two perforations, one muscularis propria catheter perforation, and one mucosal perforation were observed (3.3%).
  
  
  CONCLUSIONS
  Large mucosal target sites in the rectum and distal colon could be safely removed en bloc by means of a hybrid technique, SEMR, with blunt submucosal balloon dissection.
authors.affiliation: Developmental Endoscopy Unit, Division of Gastroenterology and Hepatology, Mayo Clinic, 200 First Street SW, Rochester, MN, USA, k.takizawa@scchr.jp.
authors.forename: Kohei
authors.initials: K
authors.lastname: Takizawa
authors.forename: Mary A
authors.initials: MA
authors.lastname: Knipschield
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Gostout
mesh_terms: D000818:Animals; D012809:Colon, Sigmoid / Q000601:surgery*; D003108:Colonic Diseases / Q000601:surgery*; D004195:Disease Models, Animal; D004210:Dissection / Q000379:methods*; D016099:Endoscopy, Gastrointestinal / Q000379:methods*; D005240:Feasibility Studies; D007413:Intestinal Mucosa / Q000601:surgery*; D012002:Rectal Diseases / Q000601:surgery*; D012007:Rectum / Q000601:surgery*; D013552:Swine