  Quantification of real-time informal feedback delivered by an experienced
surgeon to a trainee during surgery is important for skill improvements in
surgical training. Such feedback in the live operating room is inherently
multimodal, consisting of verbal conversations (e.g., questions and answers) as
well as non-verbal elements (e.g., through visual cues like pointing to
anatomic elements). In this work, we leverage a clinically-validated
five-category classification of surgical feedback: "Anatomic", "Technical",
"Procedural", "Praise" and "Visual Aid". We then develop a multi-label machine
learning model to classify these five categories of surgical feedback from
inputs of text, audio, and video modalities. The ultimate goal of our work is
to help automate the annotation of real-time contextual surgical feedback at
scale. Our automated classification of surgical feedback achieves AUCs ranging
from 71.5 to 77.6 with the fusion improving performance by 3.1%. We also show
that high-quality manual transcriptions of feedback audio from experts improve
AUCs to between 76.5 and 96.2, which demonstrates a clear path toward future
improvements. Empirically, we find that the Staged training strategy, with
first pre-training each modality separately and then training them jointly, is
more effective than training different modalities altogether. We also present
intuitive findings on the importance of modalities for different feedback
categories. This work offers an important first look at the feasibility of
automated classification of real-world live surgical feedback based on text,
audio, and video modalities.
