title: Optimizing surgical approach for natural orifice translumenal endoscopic procedures.
abstract: BACKGROUND
  Natural orifice translumenal endoscopic surgery (NOTES) often requires some degree of retroflexion of the endoscopic operating system. This study investigates the impact of retroflexion on task performance in NOTES.
  
  
  METHODS
  In a bench-top simulation, surgeons were required to manipulate a single-channel endoscope to touch 4 dots in a predetermined order. The task was performed under the forward-view and retroflexed-view conditions.
  
  
  RESULTS
  Tasks performed under the forward-view condition were significantly faster than those performed under the retroflexed-view condition (P = .005). Also, 5 experienced surgeons completed tasks in less time than the novices (P = .043). Experienced surgeons were mildly affected by the inverted image, whereas the novices were vulnerable to image malalignment.
  
  
  CONCLUSIONS
  Careful selection of the surgical approach to avoid image malalignment is suggested for safe performance of NOTES. Extensive training is required for novices to overcome the vision-motion difficulty before they can perform NOTES safely and effectively.
authors.affiliation: Gastrointestinal and Minimally Invasive Surgery Division, The Oregon Clinic, 1040 NW 22nd Ave, Suite 560, Portland, OR 97210, USA. mcassera@orclinic.com
authors.forename: Maria A
authors.initials: MA
authors.lastname: Cassera
authors.forename: Bin
authors.initials: B
authors.lastname: Zheng
authors.forename: Georg O
authors.initials: GO
authors.lastname: Spaun
authors.forename: Lee L
authors.initials: LL
authors.lastname: Swanström
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D003198:Computer Simulation; D005260:Female; D006801:Humans; D008297:Male; D057605:Natural Orifice Endoscopic Surgery / Q000193:education* / Q000379:methods*; D025321:Surgery, Computer-Assisted / Q000193:education* / Q000379:methods*; D013647:Task Performance and Analysis; D014741:Video Recording