title: Performance of Kymerax© precision-drive articulating surgical system compared to conventional laparoscopic instruments in a pelvitrainer model.
abstract: The Kymerax© Precision-Drive Articulating Surgical System by Terumo© is a handheld laparoscopic robot which permits motion in two additional degrees of freedom (deflection and rotation in the instrument tip). In a pelvitrainer model, we compared the performance of participants with different laparoscopic experiences and compared Kymerax© to conventional laparoscopic instruments.
  
  
  
  20 expert surgeons, performing more than 50 laparoscopic procedures per year, and 25 medical students without any experience in surgery at all were selected. Each participant was randomized into two groups: Group TK performed the tasks using the traditional laparoscopic Instruments (TLI) first and Kymerax© thereafter, group KT vice versa. Six standardized tasks were used: Two instructional exercises and four tasks where time, number of mistakes, and overall precision were measured. Finally, a questionnaire had to be answered.
  
  
  
  All four tasks were performed significantly more slowly with the Kymerax© device. Improved needle control in stitches towards the surgeon, significantly less deviation while cutting along different lines as well as a significantly reduced fraying of the cutting edge were found when participants were using Kymerax©. By questionnaire more than 90% of the participants indicated clear advantages using Kymerax©. However, participants needed more training time and had an earlier loss of concentration with Kymerax©. Further complaints about Kymerax© were its limitations in rotation and deflection, the impaired view as well as the non-ergonomic instrument handle. Rotation force, instrument weight, digital instrument-tip control, and needle fixation were rated as accurate.
  
  
  
  This study shows that more time is needed to solve tasks with Kymerax© compared to conventional laparoscopic instruments. Kymerax© is superior to conventional laparoscopy for suturing at difficult angles and cutting along complex structures. Kymerax© can potentially bring benefits for certain laparoscopic tasks, but as seen in this study, further developments are necessary. Terumo© meanwhile closed down its Kymerax
authors.affiliation: University of Bern, Spital Interlaken, Unterseen, Switzerland. sieber.marco@gmx.ch.|, Stockhornweg 15, 3422, Kirchberg, Switzerland. sieber.marco@gmx.ch.
authors.forename: Marco Alain
authors.initials: MA
authors.lastname: Sieber
authors.affiliation: Department of Gynecology, Inselspital Bern, Bern, Switzerland.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Fellmann-Fischer
authors.affiliation: Department of Gynecology, Inselspital Bern, Bern, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Mueller
mesh_terms: D006801:Humans; D010535:Laparoscopy / Q000295:instrumentation*; D059032:Learning Curve; D065287:Robotic Surgical Procedures / Q000295:instrumentation*; D000066908:Simulation Training
keywords: Degrees of freedom; Gynecology; Handheld robot; Kymerax; Laparoscopy; Pelvitrainer