title: Toward scar-free surgery: an analysis of the increasing complexity from laparoscopic surgery to NOTES.
abstract: BACKGROUND
  NOTES is an emerging technique for performing surgical procedures, such as cholecystectomy. Debate about its real benefit over the traditional laparoscopic technique is on-going. There have been several clinical studies comparing NOTES to conventional laparoscopic surgery. However, no work has been done to compare these techniques from a Human Factors perspective. This study presents a systematic analysis describing and comparing different existing NOTES methods to laparoscopic cholecystectomy.
  
  
  METHODS
  Videos of endoscopic/laparoscopic views from fifteen live cholecystectomies were analyzed to conduct a detailed task analysis of the NOTES technique. A hierarchical task analysis of laparoscopic cholecystectomy and several hybrid transvaginal NOTES cholecystectomies was performed and validated by expert surgeons. To identify similarities and differences between these techniques, their hierarchical decomposition trees were compared. Finally, a timeline analysis was conducted to compare the steps and substeps.
  
  
  RESULTS
  At least three variations of the NOTES technique were used for cholecystectomy. Differences between the observed techniques at the substep level of hierarchy and on the instruments being used were found. The timeline analysis showed an increase in time to perform some surgical steps and substeps in NOTES compared to laparoscopic cholecystectomy.
  
  
  CONCLUSIONS
  As pure NOTES is extremely difficult given the current state of development in instrumentation design, most surgeons utilize different hybrid methods-combination of endoscopic and laparoscopic instruments/optics. Results of our hierarchical task analysis yielded an identification of three different hybrid methods to perform cholecystectomy with significant variability among them. The varying degrees to which laparoscopic instruments are utilized to assist in NOTES methods appear to introduce different technical issues and additional tasks leading to an increase in the surgical time. The NOTES continuum of invasiveness is proposed here as a classification scheme for these methods, which was used to construct a clear roadmap for training and technology development.
authors.affiliation: Department of Surgery, Cambridge Health Alliance, Harvard Medical School, Cambridge, MA, USA, amine.chellali@issyl-lab.org.
authors.forename: Amine
authors.initials: A
authors.lastname: Chellali
authors.forename: Steven D
authors.initials: SD
authors.lastname: Schwaitzberg
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Jones
authors.forename: John
authors.initials: J
authors.lastname: Romanelli
authors.forename: Amie
authors.initials: A
authors.lastname: Miller
authors.forename: David
authors.initials: D
authors.lastname: Rattner
authors.forename: Kurt E
authors.initials: KE
authors.lastname: Roberts
authors.forename: Caroline G L
authors.initials: CG
authors.lastname: Cao
mesh_terms: D002763:Cholecystectomy / Q000295:instrumentation / Q000379:methods*; D017081:Cholecystectomy, Laparoscopic / Q000379:methods; D002921:Cicatrix; D006801:Humans; D057605:Natural Orifice Endoscopic Surgery / Q000295:instrumentation / Q000379:methods; D061646:Operative Time; D013647:Task Performance and Analysis; D014743:Videotape Recording