title: Mechanical evaluation of articulating instruments and cross-handed manipulation in laparoendoscopic single-site surgery.
abstract: BACKGROUND
  Laparoendoscopic single-site surgery (LESS) is limited by loss of triangulation and internal instruments conflict. To overcome these difficulties, some concepts have been introduced, namely, articulating instruments and cross-handed manipulation, which causes the right hand to control the left instrument tip and vice versa. The aim of this study was to compare task performance with different approaches based on a mechanical evaluation platform.
  
  
  METHODS
  A LESS mechanical evaluation platform was set up to investigate the performance of 2 tasks (suture pass-through rings and clip-cut) with 3 different settings: uncrossed manipulation with straight instruments (group A, the control group), uncrossed manipulation with articulating instruments (group B), and cross-handed manipulation with articulating instruments (group C). The operation time and average load required for accomplishment of the standard tasks were measured.
  
  
  RESULTS
  Group A presented significantly better time scores than group B, and group C consumed the longest time to accomplish the 2 tasks (P < .05). Comparing of average load required to perform the suture pass-through rings task, it differed significantly between dominant and nondominant hand in all groups (P < .01) and was less in group A and group B than group C in dominant hand (P < .01), while it was almost the same in all groups in the nondominant hand. In terms of average load requirement to accomplish clip-cut task, it was almost equal not only between group A and B but also between dominant and nondominant hand while the increase reached statistical significance when comparing group C with other groups (P < .05).
  
  
  CONCLUSIONS
  Compared with conventional devices and maneuvering techniques, articulating instruments and cross-handed manipulation are associated with longer operation time and higher workload. Instruments with better maneuverability should be developed in the future for LESS.
authors.affiliation: East Hospital of Tongji University, Shanghai, China.
authors.forename: An An
authors.initials: AA
authors.lastname: Xu
authors.affiliation: East Hospital of Tongji University, Shanghai, China zhujiangfan@hotmail.com.
authors.forename: Jiang Fan
authors.initials: JF
authors.lastname: Zhu
authors.affiliation: East Hospital of Tongji University, Shanghai, China.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Xie
authors.affiliation: East Hospital of Tongji University, Shanghai, China.
authors.forename: Yuantao
authors.initials: Y
authors.lastname: Su
mesh_terms: D000704:Analysis of Variance; D002983:Clinical Competence; D004867:Equipment Design; D006801:Humans; D020706:Laparoscopes; D010535:Laparoscopy / Q000379:methods*; D019060:Minimally Invasive Surgical Procedures / Q000295:instrumentation; D008953:Models, Anatomic; D061646:Operative Time; D018709:Statistics, Nonparametric; D013525:Surgical Instruments; D013536:Suture Techniques; D013647:Task Performance and Analysis
keywords: articulating instruments; cross-handed manipulation; laparoendoscopic single-site surgery; mechanical evaluation