67integrated into the robot’s surgeon console, utilizing the master controllers, stereo-
scopic viewer, and foot pedals. The dVSS simply hooks onto the back of the console
and connects to the console with the same cables used for integrating the robot in
the OR.
Mimic developed most of the software available on the dVSS; as such the grad-
ing metrics are very similar to those found on the dV-Trainer. Originally they looked
nearly identical, but upgrades to both simulators have caused them to diverge over
time. The majority of exercises found on the dVSS target improvement of robotic
handling and basic surgical skills, like transferring shapes from one hand to another,
moving a ring along a wire, retracting a panel using the third arm, needle driving,
and energy application.
Each attempt garners an overall percentage score, which is the summation of
numerous weighted metrics, such as completion time, economy of motion, instru-
ment collisions, excessive force, instruments out of view, master of workspace
range, and additional exercise specific values, such as drops, broken vessels, blood
loss, or misapplied energy. The majority of these scores are self- explanatory, but
the economy of motion and master of workspace range earn some confusion.
Economy of motion references instrument tip path length within the simulation, in
centimeters. Master of workspace range is the radius of the master controller’s
motion from user manipulation in the physical environment. The distinction appears
subtle but in reality can assess how effectively trainees are clutching their instru-
ments and making hesitating or unnecessary movements. Clicking on each metric
reveals a brief explanation of the score and weight.
The dVSS also houses a set of suturing exercises created by 3D systems. Each
task is graded on time to complete, time efficiency, knot tying, and needle handling.
Instead of a percentage score, for each metric, the trainee receives a green or red dot
Fig. 5.13 Four robotic simulators, their controllers, and representative simulation
5 Performance Assessment in Minimally Invasive Surgery