  With introduction of new technologies in the operating room like the da Vinci
Surgical System, training surgeons to use them effectively and efficiently is
crucial in the delivery of better patient care. Coaching by an expert surgeon
is effective in teaching relevant technical skills, but current methods to
deliver effective coaching are limited and not scalable. We present a virtual
reality simulation-based framework for automated virtual coaching in surgical
education. We implement our framework within the da Vinci Skills Simulator. We
provide three coaching modes ranging from a hands-on teacher (continuous
guidance) to a handsoff guide (assistance upon request). We present six
teaching cues targeted at critical learning elements of a needle passing task,
which are shown to the user based on the coaching mode. These cues are
graphical overlays which guide the user, inform them about sub-par performance,
and show relevant video demonstrations. We evaluated our framework in a pilot
randomized controlled trial with 16 subjects in each arm. In a post-study
questionnaire, participants reported high comprehension of feedback, and
perceived improvement in performance. After three practice repetitions of the
task, the control arm (independent learning) showed better motion efficiency
whereas the experimental arm (received real-time coaching) had better
performance of learning elements (as per the ACS Resident Skills Curriculum).
We observed statistically higher improvement in the experimental group based on
one of the metrics (related to needle grasp orientation). In conclusion, we
developed an automated coach that provides real-time cues for surgical training
and demonstrated its feasibility.
