Novel Surgical Risk Score for Calculating the Limits of Surgical Invasiveness

Abstract

Objective: Surgical treatment is invasive, and complications may be more likely in individual patients based on their physical reserve, nutritional status, and underlying disease. We developed a surgical risk score (SRS) to calculate the limits of surgical invasiveness during gastrointestinal procedures and created a versatile preoperative predictor of these limits based on patient characteristics.

Methods: We conducted a retrospective study of 1537 subjects who underwent gastrointestinal surgery at our hospital during the three-year period from January 2020 to December 2022. Subjects were classified into the complication group and the complication-free group based on the presence of postoperative complications classified as Clavien-Dindo grade III or greater. Risk prediction formulas were also calculated using risk factors determined by multivariate logistic analysis.

Results: The significant factors independently related to onset of complications were sex (odds ratio [OR]: 1.922; 95% confidence interval [CI]: 1.251-2.953; p=0.0021), gait status (OR: 2.11; 95% CI: 1.165-3.822; p=0.0163), serum albumin level (OR: 1.707; 95% CI: 1.223-2.369; p=0.0019), and extent of surgical invasion (OR: 4.679; 95% CI: 3.077-7.115; p＜0.0001). The predictive equation derived by including duration of surgery with these surgical risk factors was SRS=-1.808+0.731×(0.807+0.656×sex-0.664×gait status-0.565×serum albumin-1.568×invasiveness)+0.004×duration of surgery. The cutoff value from the ROC curve for the surgical risk of the onset of complications of Clavien-Dindo III or greater was -2.1238.

Conclusion: Retrograde extrapolation using the surgical risk prediction cutoff value allows us to estimate the time limits placed on surgery to avoid postoperative complications in individual cases. We consider this prediction formula, which allows preoperative calculation of an acceptable duration of surgery for individual cases using factors that can be easily evaluated, to be a useful score for reducing the rate of perioperative complications.