Surgical Procedure Understanding, Evaluation, and Interpretation: A Dictionary Factorization Approach

In this study, we present a novel machine learning-based technique to help surgical mentors assess surgical motion trajectories and corresponding surgical skills levels in surgical training programs. The proposed method is a variation of sparse coding and dictionary learning that is straightforward to optimize and produces approximate trajectory decomposition for structured tasks. Our approach is superior to existing stochastic or deep learning-based methods in terms of transparency of the model and interpretability of the results. We introduce a dual-sparse coding algorithm which encourages the elimination of redundant and unnecessary atoms and targets to reach the most informative dictionary, representing the most important temporal variations within a given surgical trajectory. Since surgical tool trajectories are time series signals, we further incorporate the idea of floating atoms along the temporal axis in trajectory analysis, which improves the model’s accuracy and prevents information loss in downstream tasks. Using JIGSAWS data set, we present preliminary results showing the feasibility of the proposed method for clustering and interpreting surgical trajectories in terms of user’s skills-related behaviors.