Intraoperative monitoring of laparoscopic skill development based on quantitative measures.

BACKGROUND: Methods for evaluating standard skills in the operating room typically are based on direct observation and checklists, but such evaluations are time consuming and can be subject to bias. It often is possible to acquire more objective measurements using surgical simulators. However, motor performance in simulators can differ significantly from that in the operating room. Intraoperative assessment is particularly challenging because of the significant variability between procedures related to differences in the patients, the surgical setup, and the team. This study aimed to evaluate the feasibility of using a new framework for interpreting quantitative measures acquired in the operating room to distinguish between levels of laparoscopic skill development. METHODS: Two levels of surgical skill development were observed, namely, those of three fourth-year residents and three attending surgeons performing three laparoscopic cholecystectomies each. Electromagnetic position sensors were attached by the surgeons to a 5-mm curved dissector and a 5-mm atraumatic grasper. From the tools' position histories and video recordings, time, kinematics, and movement transition measures were extracted. Various measures such as the Kolmogorov-Smirnov statistic and the Jensen-Shanon Divergence were used to provide intuitive dimensionless difference measures ranging from 0 to 1. These scores were used to compare residents and expert surgeons executing two surgical tasks: exposure of Calot's triangle and dissection of the cystic duct and artery. RESULTS: The two groups could be clearly differentiated in both tasks during monitoring for the dominant hand (analysis of variance [ANOVA] and Mann-Whitney; p < 0.05) but not for the nondominant hand. CONCLUSIONS: It is practical to acquire time, kinematic, and movement transition measures intraoperatively using video and electromagnetic position-sensing technologies. Principal component analysis proved to be a useful technique for presenting differences between skill levels based on those measures. The authors conclude that objective assessment of intraoperative surgical motor behavior is feasible and likely practical.

Correlating motor performance with surgical error in laparoscopic cholecystectomy.

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.