title: Performance analysis on physical simulator of four different instrument setups in laparo-endoscopic single-site (LESS) surgery.
abstract: BACKGROUND
  Over the past decades, minimally invasive surgery has undergone continuous development due to the demand for scarless results, with laparo-endoscopic single-site (LESS) surgery constituting one of today's most favored alternatives. In this study, we aim to assess the relative technical difficulty and performance benefits of dynamic articulating and pre-bent instruments, either combined with conventional laparoscopic tools or not, during the completion of two basic tasks hands-on simulator.
  
  
  METHODS
  A total of 20 surgeons were included and performed two basic simulator tasks-coordination and cutting-carried out using four different combinations of LESS-designed and straight conventional laparoscopy instruments. Assessment took place before and after the completion of a 14-week training program. Performance data were objectively analyzed over video recordings with an adapted global rating scale (a-GRS) for performance evaluation, combined with a registry of total trial completion time.
  
  
  RESULTS
  In the coordination task, the worst performance scores (p < 0.001) and longest completion times (p < 0.001 on first assessment and p < 0.01 on last assessment) were obtained with the two dynamic articulating tip instruments. On the cut trials, no significant differences between the different setups were found in a-GRS scores. The two dynamic articulating tip instruments also constituted the most time-demanding setup on both assessment trials (p < 0.05). The use of two dynamic articulating tip instruments showed significant improvement with training in all measured parameters except for performance in the cut task, in which the increase in a-GRS score was not significant.
  
  
  CONCLUSIONS
  We conclude that the least adequate instrument set for initiation in LESS surgery is the one that combines two dynamic articulating tip instruments, as this has consistently obtained the worst results in all trials. Further data on more complex tasks and on a complete learning and skills-acquisition program must be obtained to confirm these findings.
authors.affiliation: Scientific Direction, Minimally Invasive Surgery Centre Jesús Usón, Cáceres, Spain.
authors.forename: Francisco Miguel
authors.initials: FM
authors.lastname: Sánchez-Margallo
authors.forename: Ana Maria
authors.initials: AM
authors.lastname: Matos-Azevedo
authors.forename: Francisco Julián
authors.initials: FJ
authors.lastname: Pérez-Duarte
authors.forename: Silvia
authors.initials: S
authors.lastname: Enciso
authors.forename: Idoia Díaz-Guëmes
authors.initials: ID
authors.lastname: Martín-Portugués
mesh_terms: D002983:Clinical Competence; D003198:Computer Simulation; D004502:Education, Medical, Continuing / Q000379:methods*; D004521:Educational Measurement / Q000379:methods*; D004724:Endoscopy / Q000193:education / Q000295:instrumentation*; D004867:Equipment Design; D005260:Female; D006801:Humans; D010535:Laparoscopy / Q000193:education / Q000295:instrumentation*; D008297:Male; D014741:Video Recording