title: The role of tactile feedback in grip force during laparoscopic training tasks.
abstract: BACKGROUND
  Laparoscopic minimally invasive surgery has revolutionized surgical care by reducing trauma to the patient, thereby decreasing the need for medication and shortening recovery times. During open procedures, surgeons can directly feel tissue characteristics. However, in laparoscopic surgery, tactile feedback during grip is attenuated and limited to the resistance felt in the tool handle. Excessive grip force during laparoscopic surgery can lead to tissue damage. Providing additional supplementary tactile feedback may allow subjects to have better control of grip force and identification of tissue characteristics, potentially decreasing the learning curve associated with complex minimally invasive techniques.
  
  
  METHODS
  A tactile feedback system has been developed and integrated into a modified laparoscopic grasper that allows forces applied at the grasper tips to be felt by the surgeon's hands. In this study, 15 subjects (11 novices, 4 experts) were asked to perform single-handed peg transfers using these laparoscopic graspers in three trials (feedback OFF, ON, OFF). Peak and average grip forces (newtons) during each grip event were measured and compared using a Wilcoxon ranked test in which each subject served as his or her own control.
  
  
  RESULTS
  After activating the tactile feedback system, the novice subject population showed significant decreases in grip force (p < 0.003). When the system was deactivated for the third trial, there were significant increases in grip force (p < 0.003). Expert subjects showed no significant improvements with the addition of tactile feedback (p > 0.05 in all cases).
  
  
  CONCLUSIONS
  Supplementary tactile feedback helped novice subjects reduce grip force during the laparoscopic training task but did not offer improvements for the four expert subjects. This indicates that tactile feedback may be beneficial for laparoscopic training but has limited long-term use in the nonrobotic setting.
authors.affiliation: UCLA Center for Advanced Surgical and Interventional Technology (CASIT), Los Angeles, CA, USA. cwottawa@ucla.edu
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Wottawa
authors.forename: Jeremiah R
authors.initials: JR
authors.lastname: Cohen
authors.forename: Richard E
authors.initials: RE
authors.lastname: Fan
authors.forename: James W
authors.initials: JW
authors.lastname: Bisley
authors.forename: Martin O
authors.initials: MO
authors.lastname: Culjat
authors.forename: Warren S
authors.initials: WS
authors.lastname: Grundfest
authors.forename: Erik P
authors.initials: EP
authors.lastname: Dutson
mesh_terms: D002983:Clinical Competence; D004867:Equipment Design; D005246:Feedback; D018737:Hand Strength; D006801:Humans; D010535:Laparoscopy / Q000193:education* / Q000295:instrumentation*; D014110:Touch