ESIP: Explicit Surgical Instrument Prompting for Surgical Workflow Recognition

Surgical workflow recognition (SWR) stands as a pivotal component in computer-assisted surgery and is dedicated to identifying phases from surgical videos. Many deep learning-based methods have been proposed for this task and achieved acceptable SWR results. However, these methods usually implicitly extract and aggregate spatio-temporal features, so that it is challenging for these methods to adequately use some spatial information that is strongly relevant to surgical phase in SWR task, such as the information from the surgical instruments. To address this issue, an Explicit Surgical Instrument Prompting (ESIP) approach is proposed for SWR task. ESIP leverages surgical instrument segmentation to generate instrument-specific visual prompts, which explicitly guide the extraction of crucial intra-frame spatial features through a frozen pre-trained backbone, then enable effective inter-frame spatio-temporal feature extraction and aggregation. Unlike multi-task approaches that jointly perform SWR with auxiliary tasks within a shared network framework, ESIP is a single-task SWR approach dedicated to optimize framework itself for more adequate feature extraction. Furthermore, to accomplish the segmentation prompting efficiently, this paper presents SAM-based segmentation with prompt tuning strategy to explicitly integrate segmentation features into spatial features. Experimental results on Cholec80, M2CAI and AutoLaparo datasets demonstrate that our ESIP method achieves the best performance in comparison with 16 SOTA methods, with a Precision of 91.8%, 89.5% and 89.6%, Recall of 92.2%, 89.5% and 76.9%, Jaccard of 83.3%, 77.0% and 67.3%, respectively.