Developing an artificial intelligence model for phase recognition in robot-assisted radical prostatectomy.

OBJECTIVES

To develop and evaluate a convolutional neural network (CNN)-based model for recognising surgical phases in robot-assisted laparoscopic radical prostatectomy (RARP), with an emphasis on model interpretability and cross-platform validation.

METHODS

A CNN using EfficientNet B7 was trained on video data from 75 RARP cases with the hinotori robotic system. Seven phases were annotated: bladder drop, prostate preparation, bladder neck dissection, seminal vesicle dissection, posterior dissection, apical dissection, and vesicourethral anastomosis. A total of 808 774 video frames were extracted at 1 frame/s for training and testing. Validation was performed on 25 RARP cases using the da Vinci robotic system to assess cross-platform generalisability. Gradient-weighted class activation mapping was used to enhance interpretability by identifying key regions of interest for phase classification.

RESULTS

The CNN achieved 0.90 accuracy on the hinotori test set but dropped to 0.64 on the da Vinci dataset, thus indicating cross-platform limitations. Phase-specific F1 scores ranged from 0.77 to 0.97, with lower performance in the phase of seminal vesicle dissection, and apical dissection. Gradient-weighted class activation mapping visualisations revealed the model's focus on central pelvic structures rather than transient instruments, enhancing interpretability and insights into phase classification.

CONCLUSIONS

The model demonstrated high accuracy on a single robotic platform but requires further refinement for consistent cross-platform performance. Interpretability techniques will foster clinical trust and integration into workflows, advancing robotic surgery applications.