Basic features and clinical applicability of ‘Preliminary Universal Surgical Invasiveness Score’ (pUSIS): A multi-centre pilot study

Objective: There is still a lack of a universally applicable and comprehensive scoring system for documenting the invasiveness of surgical procedures. The proposed preliminary ‘Universal Surgical Invasiveness Score’ (pUSIS) is intended to fill this gap. Methods: We used the recently developed pUSIS to obtain values from 8 types of surgery and 80 individual interventions. The results were analysed using descriptive statistical methods. The degree of difficulty on a scale from 0 (very easy) to 10 (extremely difficult) and time expenditures for assessing pUSIS were documented. Results: Individual pUSIS values ranged from 8 in a laparoscopic cholecystectomy case to 36 in a total hip replacement case. The lowest median pUSIS value of 11.5 was found for laparoscopic cholecystectomy and the highest value of 24.5 was found for open thoracic surgery. The correlation between pUSIS values and the duration of surgery resulted in a tight linear regression (R2=0.6419). The lowest mean (±SD) difficulty level to obtain pUSIS values was 1.6±0.6 for sleeve gastrectomy and the highest one was 2.9±0.6 for knee replacement. The duration to finalise the calculations was 4.1±1.1 min for video-assisted thoracoscopy (VATS) and 9.4±1.3 min for sleeve gastrectomy. Conclusion: We concluded that pUSIS has the potential to be a useful, simply obtainable and universal assessment tool for quantification of the magnitude and invasiveness of individual surgical operations and can serve as a means to quantify surgical interventions for outcome research and evaluate surgical performance.