title: Directed submucosal tunneling permits in-line endoscope positioning for transgastric natural orifice translumenal endoscopic surgery (NOTES).
abstract: BACKGROUND
  Submucosal dissection is demonstrated to be a technically feasible, safe means of obtaining peroral transgastric peritoneal access for natural orifice translumenal endoscopic surgery (NOTES). The authors hypothesized that their previously described self-approximating translumenal access technique (STAT) could be used to create directed gastric submucosal tunnels permitting in-line endoscope positioning with predetermined abdominal locations that might otherwise be difficult to access.
  
  
  METHODS
  In this study, 14 domestic farm swine underwent peroral transgastric peritoneoscopy. Under direct endoscopic visualization, a submucosal tunnel was created by dissecting between the mucosal and muscular layers of the stomach. Each tunnel was created with one of four intraabdominal locations (right upper quadrant, left upper quadrant, lesser sac, and pelvis) as the final target for in-line endoscope positioning. Once peritoneal access had been achieved, in-line positioning was assessed and peritoneoscopy was performed. The submucosal tunnels were closed with endoscopically placed clips. The animals were killed 2 weeks after the procedure, and necropsy was performed.
  
  
  RESULTS
  Submucosal tunnels were successfully directed at predetermined intraabdominal targets in 12 of the 14 animals. The mean dissection time required to create the tunnel was 51 +/- 32 min. All the transgastric tunnels were successfully closed with endoscopically placed clips (mean, 3.2 +/- 1.1), and at necropsy showed no evidence of gastrotomy leak in any of the animals. One animal experienced a duodenal perforation unrelated to the transgastric tunneling and was killed on postoperative day 2. The remaining animals recovered and gained weight (mean, 5.5 +/- 1.2 kg) in the 2-week survival period.
  
  
  CONCLUSIONS
  Directed submucosal dissection is technically feasible in a porcine model and permits in-line endoscope positioning with predetermined abdominal target locations. The STAT approach provides safe peritoneal access, allows for a simple reliable endoclip closure, and has an excellent short-term survival rate. This method of achieving transgastric access may be an enabling technique for future NOTES procedures.
authors.affiliation: Section of Minimally Invasive and Bariatric Surgery, Department of Surgery, Penn State Milton S. Hershey Medical Center, Hershey, PA, USA. epauli@hmc.psu.edu
authors.forename: Eric Mark
authors.initials: EM
authors.lastname: Pauli
authors.forename: Randy S
authors.initials: RS
authors.lastname: Haluck
authors.forename: Adrian M
authors.initials: AM
authors.lastname: Ionescu
authors.forename: Ann M
authors.initials: AM
authors.lastname: Rogers
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Shope
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Moyer
authors.forename: Arnab
authors.initials: A
authors.lastname: Biswas
authors.forename: Abraham
authors.initials: A
authors.lastname: Mathew
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004210:Dissection / Q000379:methods*; D020776:Endoscopes, Gastrointestinal; D016099:Endoscopy, Gastrointestinal / Q000379:methods*; D004867:Equipment Design; D005260:Female; D005753:Gastric Mucosa / Q000601:surgery*; D005774:Gastrostomy / Q000295:instrumentation*; D034421:Sus scrofa