The anterior abdominal wall in laparoscopic procedures and limitations of laparoscopic simulators

Towards automatic skill evaluation: detection and segmentation of robot-assisted surgical motions

This paper reports our progress in developing techniques for "parsing" raw motion data from a simple surgical task into a labeled sequence of surgical gestures. The ability to automatically detect and segment surgical motion can be useful in evaluating surgical skill, providing surgical training feedback, or documenting essential aspects of a procedure. If processed online, the information can be used to provide context-specific information or motion enhancements to the surgeon. However, in every case, the key step is to relate recorded motion data to a model of the procedure being performed. Robotic surgical systems such as the da Vinci system from Intuitive Surgical provide a rich source of motion and video data from surgical procedures. The application programming interface (API) of the da Vinci outputs 192 kinematics values at 10 Hz. Through a series of feature-processing steps, tailored to this task, the highly redundant features are projected to a compact and discriminative space. The resulting classifier is simple and effective.Cross-validation experiments show that the proposed approach can achieve accuracies higher than 90% when segmenting gestures in a 4-throw suturing task, for both expert and intermediate surgeons. These preliminary results suggest that gesture-specific features can be extracted to provide highly accurate surgical skill evaluation.

Automatic Detection and Segmentation of Robot-Assisted Surgical Motions

Robotic surgical systems such as Intuitive Surgical's da Vinci system provide a rich source of motion and video data from surgical procedures. In principle, this data can be used to evaluate surgical skill, provide surgical training feedback, or document essential aspects of a procedure. If processed online, the data can be used to provide context-specific information or motion enhancements to the surgeon. However, in every case, the key step is to relate recorded motion data to a model of the procedure being performed. This paper examines our progress at developing techniques for "parsing" raw motion data from a surgical task into a labelled sequence of surgical gestures. Our current techniques have achieved >90% fully automated recognition rates on 15 datasets.

Effect of the angle between the optical axis of the endoscope and the instruments' plane on monitor image and surgical performance

BACKGROUND

The aim of the study was to examine the effect of the angle between optical axis of the endoscope and the instruments' plane (OAIP) on the monitor display angle (approach angle between the two instruments on a two-dimensional monitor) and endoscopic task performance.

METHODS

Two experiments were carried out in the Advanced Dundee Endoscopic Psychomotor Tester (ADEPT) using a standard two-dimensional video endoscopic system. In the first experiment, the monitor display angle was measured during use, with OAIP angles ranging between 0 and 80 degrees (at 10 degrees increments) and manipulation angles varying between 45 and 120 degrees (at 15 degrees increments). In the second experiment, 10 surgeons tied 500 intracorporeal knots with OAIP angles of 0 degrees (optical axis in the same plane as the instruments), +15 degrees and +30 degrees (viewing above the instruments' plane), and -15 and -30 degrees (optical axis looking from below instruments' plane). The end points were the execution time and knot quality score (KQS).

RESULTS

In the first experiment, instruments entered the visual field from lateral sides of the monitor with an apparent 180 degrees monitor display angle with a 0 degrees OAIP angle, whereas the monitor display angle approached the actual manipulation angle between the two needle drivers when an 80 degrees OAIP angle was used. In the second experiment, the instruments appeared to enter the image field from the side of the surgeon when the endoscope viewed the instruments from above, whereas instruments entered the field from the opposite side to the surgeon when the endoscope viewed instruments' plane from below. As a result, use of 0 and +15 degrees OATP angles yielded significantly shorter execution times: 70 s compared to 83, 93, and 77 s for +30, -30, and -15 degrees OAIP angles ( p < 0.001), with KQS of 39 degrees and 40 vs 38, 36, and 34%, respectively ( p = 0.257).

CONCLUSIONS

The angle between the optical axis of the endoscope and instruments' plane determines how the instruments appear to enter the operative field. The monitor display angle between the instruments is different from the real manipulation angle unless the OAIP angle is near 80 degrees. The apparent entry of instruments into the operative field becomes intuitive for the surgeon only if the endoscope is viewing from above or in the same plane as the instruments. Hence, the best performance for endoscopic knot tying is obtained with this configuration, and execution time increases significantly with viewing from below the instruments' plane.