HPB P46 Does the CholeS pre-operative risk score for laparoscopic cholecystectomy correlate to operative time? A single centre experience
Authors: Siracusa Francesca , Longbotham David , Pellen Michael 
Published: December 2022

Abstract

Background
NHS waiting lists for elective surgeries including non-urgent laparoscopic cholecystectomies (LC) have severely escalated during the Covid-19 pandemic, with some patients waiting over 2 years for their operations. LCs are highly variable in terms of operative time, difficulty, and risk making theatre utilisation a challenge to effectively clear waiting lists. Nassar et al.[1] developed and validated a pre-operative risk prediction score for predicting the difficult LC using an objective operative difficulty grading system. We aimed to assess if application of CholeS could be used to predict which LC may have longer operative times, and so aid theatre utilisation planning.

Methods
Consecutive elective LCs performed between May and October 2021 at our institution's day surgery unit were included and analysed. Each patient was scored retrospectively using the CholeS pre-operative risk score from electronic patient records. Operative time was obtained from theatre electronic record systems. Data was collected on conversion to open surgery, post-operative day of discharge, and intra or post-operative complications. Outliers with operating time recorded as &lt;20 minutes were considered data entry errors and excluded from analysis.
A ROC analysis was used, which determined a threshold value of 3. This value was used to divide patients into a low-risk (≤3 points) and high-risk (four and above) group.
Two-sample independent t-test was used to compare mean operative time between the high-risk and low-risk CholeS score groups. Levene's test was used to determine if variance was equal between groups.
SPSS version 27[2] was used for data analysis and statistical tests and p&lt;0.05 was deemed significant.

Results
81 LC were included for analysis. 53 patients were low-risk and 26 patients were high-risk. There was a significantly lower operative time in the low-risk group: low-risk = 57.6 minutes (95% CI 52.4–63.0) vs high-risk = 75.8 minutes (95% CI 58.7–92.9), p=0.046. Nine patients had surgeries lasting &gt;90 minutes; 66% of these were in the high-risk LC group.
95% of patients were discharged on day 0, two patients on day 1, and two on day 2 or later. Three patients had conversion to open cholecystectomy and five patients had post-operative complications. Two out of three patients who required conversion to open cholecystectomies were in high-risk patients with high CholeS scores (7 and 10). In one patient, a cholecystoduodenal fistula was found. Cystic duct avulsion occurred in the other. Three out of five patients with post-operative complications were in the high-risk group, with corresponding higher Clavien-Dindo scores (3b, 2 and 2) when compared to the low-risk group (1 for both patients).

Conclusions
The CholeS pre-operative scoring system could be used to optimise LC theatre allocation. A score of ≤3 has a shorter operative time than a patient with a score of four or more (mean difference = 18.1 mins, 95% CI 4.4–31.9). Prediction of which LCs will be shorter operations could improve theatre utilisation and allow extra cases booking on the operating list. This, in turn, could help reduce the number of patients on the waiting list.
Additionally, CholeS could be used to predict patients with more challenging and prolonged operations as well as those at higher risk of open conversion and complications. This could allow such patients to be managed by allocation to inpatient specialist upper GI specialist lists.
[1] Nassar, A.H.M., Hodson, J., Ng, H.J. et al. Predicting the difficult laparoscopic cholecystectomy: development and validation of a pre-operative risk score using an objective operative difficulty grading system. Surg Endosc 34, 4549–4561 (2020).
[2] IBM Corp. Released 2020. IBM SPSS Statistics for Windows, Version 27.0. Armonk, NY: IBM Corp.