# Surgical Phase Recognition: From Public Datasets to Real-World Data
## 5 Conclusions  
In this work, we presented the results of the analysis of a new large-scale private dataset for phase recognition in laparoscopic cholecystectomy videos. Our analysis showed a discrepancy in the data distributions of videos in our dataset and in the most commonly used public dataset for phase recognition, Cholec80.  
Additionally, we performed an exhaustive performance analysis of state-of-the-art phase recognition models on our dataset. Models struggled to recognize less prevalent surgical phases which are characteristic of our dataset.  
Overall, our results highlighted the need to better understand the distribution of the video data phase that recognition models are trained on. In particular, we shed the light on the risk of model selection bias when developing models on video data that under-represents real-world scenarios.  
Our future work will focus on improving the model performance in recognizing extremely under-represented surgical phases.  
The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app12178746/s1](https://www.mdpi.com/article/10.3390/app12178746/s1)]([https://www.mdpi.com/article/10.3390/app12178746/s1](https://www.mdpi.com/article/10.3390/app12178746/s1)), Figure S1: Distribution of video durations (in minutes) in our dataset and Cholec80. Our dataset shows more variability in durations and have longer videos than Cholec80.; Figure S2: Distribution of phase presence as percentage in total number of videos. Some phases are extremely underrepresented across videos. For example, Gallbladder drainage and Liver biopsy are present only in 0.6% and 0.4% of videos in our dataset, respectively.; Figure S3: Distribution of phase duration as percentage of total duration in our dataset and Cholec80. The imbalance between phases for both datasets is severe. Gallbladder drainage and Liver biopsy phases are extremely underrepresented in our dataset, with 0.15% and 0.06% duration, respectively; Table S1: Definitions of phases.  
Conceptualization, K.K. and F.A.; Data curation, K.K., J.L.L. and G.B.; Formal analysis, K.K.; Investigation, K.K. and F.A.; Methodology, K.K. and F.A.; Project administration, M.S. and M.S.W.; Resources, M.S. and M.S.W.; Software, K.K.; Supervision, N.A., M.S., M.S.W. and F.A.; Validation, K.K.; Visualization, K.K.; Writing--original draft, K.K.; Writing--review and editing, K.K., J.L.L., G.B. and F.A. All authors have read and agreed to the published version of the manuscript.  
[PERSON] was funded by the Swiss National Science Foundation grant number P500 PM_206724, accessed on 1 March 2022.  
The institutional review board--the ethics committee of the Canton of Bern--approved the study design, the use of laparoscopic videos, and waived the need to obtain informed consent (KEK 2018-01964). All methods were performed in accordance with the relevant guidelines and regulations.  
The data that support the findings of this study consist of published and restricted data. Published data are available from the reported references. Restricted data are not publicly available.  
The authors declare no conflict of interest[PERSON]