title: The influence of force feedback and visual feedback in grasping tissue laparoscopically.
abstract: BACKGROUND
  Due to the limited force feedback provided by laparoscopic instruments, surgeons may have difficulty in applying the appropriate force on the tissue. The aim of this study was to determine the influence of force feedback and visual feedback on the exerted pinch force.
  
  
  METHODS
  A grasper with a force sensor in the jaws was developed. Subjects with and without laparoscopic experience grasped and pulled pig bowel with a force of 5 N. The applied pinch force was measured during tasks of 1-s and 1-min duration. Visual feedback was provided in half the measurements. Force feedback was adjusted by changing the mechanical efficiency of the forceps from 30% to 90%.
  
  
  RESULTS
  The mean pinch force applied was 6.8 N (+/-0.5), whereas the force to prevent slippage was 3.0 N (+/-0.4). Improving the mechanical efficiency had no effect on the pinch force for the 1-s measurements. The amount of excessive pinch force when holding tissue for 1 min was lower at 30% mechanical efficiency compared with 90% (105% vs 131%, p = 0.04). The tissue slipped more often when the subject had no visual feedback (2% vs 8%, p = 0.02).
  
  
  CONCLUSIONS
  Force feedback and visual feedback play a more limited role than expected in the task of grasping tissue with laparoscopic forceps.
authors.affiliation: Man-Machine Systems Group, Faculty of Mechanical Engineering and Marine Technology, Delft University of Technology, Mekelweg 2, 2628 CD, Delft, The Netherlands. e.a.m.heijnsdijk@wbmt.tudelft.nl
authors.forename: E A M
authors.initials: EA
authors.lastname: Heijnsdijk
authors.forename: A
authors.initials: A
authors.lastname: Pasdeloup
authors.forename: A J
authors.initials: AJ
authors.lastname: van der Pijl
authors.forename: J
authors.initials: J
authors.lastname: Dankelman
authors.forename: D J
authors.initials: DJ
authors.lastname: Gouma
mesh_terms: D000818:Animals; D004867:Equipment Design; D030141:Feedback, Psychological; D018737:Hand Strength; D006801:Humans; D007421:Intestine, Small / Q000293:injuries / Q000601:surgery; D007721:Knowledge of Results, Psychological; D010535:Laparoscopy / Q000523:psychology; D010820:Physicians / Q000523:psychology*; D011597:Psychomotor Performance; D013314:Stress, Mechanical; D013525:Surgical Instruments; D011795:Surveys and Questionnaires; D013552:Swine; D014110:Touch; D014796:Visual Perception