title: EUS in localizing safe alternate access sites for natural orifice transluminal endoscopic surgery: initial experience in a porcine model.
abstract: BACKGROUND
  Most natural orifice transluminal endoscopic surgery (NOTES) procedures have been performed through the anterior stomach wall, based on the established safety of PEG placement. This approach does not afford mechanically efficient access to all anatomic areas of interest.
  
  
  OBJECTIVE
  To assess the utility of EUS in identifying safe alternate access sites for NOTES.
  
  
  METHODS
  Nonsurvival animal experiment.
  
  
  METHODS
  Thirty-two EUS-guided access procedures were performed through the antrum, the posterior stomach wall, or the rectum of 12 pigs. Sixteen safe-access procedures (SAP) used sonographic guidance to achieve safe intraperitoneal access by avoiding extraluminal organs and vessels during the initial NOTES puncture. Sixteen unsafe-access procedures (UAP) evaluated potential complications of blind access by performing a standard NOTES puncture at sites adjacent to critical extraluminal structures identified by EUS. Access was achieved by using a similar technique for both SAPs and UAPs. Baseline and completion laparotomies were performed.
  
  
  RESULTS
  All 16 UAPs resulted in clinically relevant complications, such as liver laceration and iliac artery injury. In contrast, 13 SAPs were without complication. The 3 complications in the SAP group occurred with transrectal access and consisted of 2 minor complications and a small-bowel perforation.
  
  
  CONCLUSIONS
  Blind NOTES access through the antrum, posterior stomach wall, and rectum could result in catastrophic complications. In contrast, EUS-guided access through these sites substantially reduced but did not completely eliminate this risk. EUS appears promising as an adjunct to NOTES access, particularly as more experience is gained in definitively excluding the presence of at-risk extraluminal structures.
authors.affiliation: Division of Gastroenterology, University of Michigan Medical Center, Ann Arbor, Michigan 48109, USA. badihe@umich.edu
authors.forename: B Joseph
authors.initials: BJ
authors.lastname: Elmunzer
authors.forename: Steve J
authors.initials: SJ
authors.lastname: Schomisch
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Trunzo
authors.forename: Benjamin K
authors.initials: BK
authors.lastname: Poulose
authors.forename: Conor P
authors.initials: CP
authors.lastname: Delaney
authors.forename: Michael F
authors.initials: MF
authors.lastname: McGee
authors.forename: Ashley L
authors.initials: AL
authors.lastname: Faulx
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Marks
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Ponsky
authors.forename: Amitabh
authors.initials: A
authors.lastname: Chak
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004724:Endoscopy / Q000009:adverse effects / Q000379:methods*; D016099:Endoscopy, Gastrointestinal / Q000009:adverse effects / Q000379:methods*; D019160:Endosonography; D005704:Gallbladder / Q000000981:diagnostic imaging; D020699:Gastroscopes; D011897:Random Allocation; D012007:Rectum / Q000000981:diagnostic imaging; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D013270:Stomach / Q000601:surgery; D034421:Sus scrofa; D013552:Swine; D001743:Urinary Bladder / Q000000981:diagnostic imaging