title: Transgastric or trans-sigmoidal? The impact of the choice of access on task performance in target natural orifice translumenal endoscopic surgery procedures.
abstract: BACKGROUND
  The effect of the choice of access upon endoscope control during a navigational task is explored within a simulator model.
  
  
  METHODS
  The study was conducted within the endoscopic-laparoscopic interdisciplinary training entity (ELITE) model (Minimally Invasive Therapy and Intervention Research Group [MITI], Technische Universität, Germany)--a validated natural orifice translumenal endoscopic surgery (NOTES) simulator. Seventeen subjects, 15 with no endoscopic experience, navigated the endoscope from predefined trans-sigmoidal and transgastric access points to the appendix and the gallbladder. A previously defined and validated quantitative analysis of endoscope control, in addition to time taken to complete the task, was used to evaluate overall performance. The quantitative analysis extrapolated the movements of the subject's wrist in control of the endoscope and rated the movements using a scoring system of 0-3 based upon the smoothness of the movements recorded.
  
  
  RESULTS
  Although no significant difference in terms of performance time was demonstrated between the two approaches to the appendix (36.6 ± 14.7 seconds TG and 29.8 ± 16 seconds TS) (P = .214), when the endoscope control score was compared, a significant difference was confirmed (3 TG and 7 TS) (P < .001). With regard to the approach to the gallbladder, a significant difference in terms of both the performance time (19.8 seconds TG and 35.6 seconds TS) (P < .001) and the quality of endoscope control (7 TG and 5 TS) (P = .001) was demonstrated.
  
  
  CONCLUSIONS
  The choice of access route impacts directly on the ease with which the endoscopist navigates to the target. Within this study, the trans-sigmoidal appears the most appropriate to access the appendix and the transgastric for the gallbladder.
authors.affiliation: Department of Surgery and Cancer, Imperial College London, London, United Kingdom. j.clark@imperial.ac.uk
authors.forename: James
authors.initials: J
authors.lastname: Clark
authors.forename: Sonja
authors.initials: S
authors.lastname: Gillen
authors.forename: David R C
authors.initials: DR
authors.lastname: James
authors.forename: Adam
authors.initials: A
authors.lastname: Fiolka
authors.forename: Vahe
authors.initials: V
authors.lastname: Karimyan
authors.forename: Mikael
authors.initials: M
authors.lastname: Sodergren
authors.forename: Felipe
authors.initials: F
authors.lastname: Orihuela-Espina
authors.forename: Helmut
authors.initials: H
authors.lastname: Friess
authors.forename: Ara
authors.initials: A
authors.lastname: Darzi
authors.forename: Hubertus D
authors.initials: HD
authors.lastname: Feussner
authors.forename: Guang-Zhong
authors.initials: GZ
authors.lastname: Yang
mesh_terms: D001062:Appendectomy / Q000379:methods*; D017081:Cholecystectomy, Laparoscopic / Q000379:methods*; D002983:Clinical Competence; D012809:Colon, Sigmoid / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D057605:Natural Orifice Endoscopic Surgery / Q000379:methods*; D013270:Stomach / Q000601:surgery; D013647:Task Performance and Analysis