title: Correlating motor performance with surgical error in laparoscopic cholecystectomy.
abstract: BACKGROUND
  Analysis of motor performance in minimally invasive surgery (MIS) is a new field with applications in surgical training, surgical simulators, and robotics. Force/torque and derivatives of tool tip position (velocity, acceleration, and jerk) are examples of measures of motor performance (MMPs). Few studies have measured MMPs or have correlated MMPs with surgical performance during MIS on humans. The objectives of this study were to determine the feasibility of a novel multimodal system to quantify MMPs in laparoscopic cholecystectomy and to attempt to correlate MMPs with the magnitude of error as a measure of surgical performance.
  
  
  METHODS
  Novice and expert surgeons performed laparoscopic cholecystectomies in two groups of three patients each. MMPs were obtained using a combination of optical and electromagnetic tool tip tracking and a force/torque sensor on a modified Maryland dissector. Error scores for laparoscopic cholecystectomy were calculated using a previously validated system. Novice and expert measurements were compared, and correlations were made between error scores and MMPs.
  
  
  RESULTS
  Error scores were similar between novices and experts. Novice surgeons had a significantly greater mean velocity (566 +/- 83 vs 85 +/- 32 mm/s, p = 0.006) and acceleration (2,600 +/- 760 vs 440 +/- 174 mm/s2, p = 0.050) compared to expert surgeons. Force (16.5 +/- 4.6 vs 18.3 +/- 6.0 N, p = 0.829), position (121 +/- 25 vs 135 +/- 72 mm, p = 0.863), and jerk (19,600 +/- 7,410 vs 2,430 +/- 367 mm/s3, p = 0.138) were similar between groups. A positive correlation was found in novice surgeons between error score and jerk (Pearson correlation, 0.999; p = 0.035).
  
  
  CONCLUSIONS
  It is feasible to quantify MMPs in laparoscopic cholecystectomy. Novice and expert surgeons can be differentiated by MMPs; moreover, there may be a positive correlation between jerk and error score in novice surgeons.
authors.affiliation: Department of Surgery, University of British Columbia, Vancouver, British Columbia, V5Z 4E3, Canada.
authors.forename: H
authors.initials: H
authors.lastname: Hwang
authors.forename: J
authors.initials: J
authors.lastname: Lim
authors.forename: C
authors.initials: C
authors.lastname: Kinnaird
authors.forename: A G
authors.initials: AG
authors.lastname: Nagy
authors.forename: O N M
authors.initials: ON
authors.lastname: Panton
authors.forename: A J
authors.initials: AJ
authors.lastname: Hodgson
authors.forename: K A
authors.initials: KA
authors.lastname: Qayumi
mesh_terms: D000328:Adult; D017081:Cholecystectomy, Laparoscopic; D002983:Clinical Competence; D055590:Electromagnetic Phenomena / Q000295:instrumentation / Q000379:methods; D004867:Equipment Design; D005240:Feasibility Studies; D013502:General Surgery; D006801:Humans; D007396:Internship and Residency; D019300:Medical Errors; D008503:Medical Staff; D009048:Motor Skills; D055095:Optics and Photonics / Q000295:instrumentation; D013996:Time and Motion Studies