title: Differences in grip forces among various robotic instruments and da Vinci surgical platforms.
abstract: BACKGROUND
  The da Vinci surgical platform is becoming increasingly available and utilized. Due to the lack of haptic feedback, visual cues are necessary to estimate grip forces and tissue tensions during surgery. We directly measured the grip forces of robotic EndoWrist instruments using the three available da Vinci robotic surgical platforms.
  
  
  METHODS
  Robotic instruments were tested in the da Vinci S, Si, and Standard systems. A load cell was placed in a housing unit that allowed for measurement of the grip forces applied by the tip of each robotic instrument. Each instrument was tested six times, and all data were analyzed using Student's t-tests or analysis of variance when appropriate.
  
  
  RESULTS
  Slight differences in grip force were seen when the instrument was tested through 2 degrees of freedom at the tip (p = 0.02, analysis of variance) and when comparing a new instrument to an older instrument (p = 0.001 at the neutral position). There was no statistical difference in grip force between the left and right robotic arms. There was a broad range of grip forces between the various robotic instruments. The lowest grip force was registered in the double fenestrated grasper (2.26 ± 0.15 N), whereas the highest was seen in the Hem-o-lok clip applier (39.92 ± 0.89 N). In comparison to the S and Si, the Standard platform appeared to have significantly higher grip forces.
  
  
  CONCLUSIONS
  Different grip forces were observed among the various robotic instruments commonly used during urologic surgery and between the Standard and the S and Si platforms.
authors.affiliation: Department of Urology, University of California-Irvine, Orange, California 92868, USA. pmucksav@uci.edu
authors.forename: Phillip
authors.initials: P
authors.lastname: Mucksavage
authors.forename: David C
authors.initials: DC
authors.lastname: Kerbl
authors.forename: Donald L
authors.initials: DL
authors.lastname: Pick
authors.forename: Jason Y
authors.initials: JY
authors.lastname: Lee
authors.forename: Elspeth M
authors.initials: EM
authors.lastname: McDougall
authors.forename: Michael K
authors.initials: MK
authors.lastname: Louie
mesh_terms: D018737:Hand Strength / Q000502:physiology*; D055595:Mechanical Phenomena; D012371:Robotics / Q000295:instrumentation*; D013525:Surgical Instruments