Page 62 - World Journal of Laparoscopic Surgery

Validation of CLOC Score
The various predictive preoperative scoring systems of results
conversion from laparoscopic to open cholecystectomy have been
proposed. However, the clinical benefits are limited due to small Baseline Characteristics
sample sizes and/or lack of validation. Sutcliffe et al. has proposed A total of 163 subjects were included in this study, with a mean
the CLOC risk score according to the CholeS prospective study age of 51.06 ± 13.3 years. Data on subjects’ age were distributed
involving 8820 subjects. The results were patients with a CLOC score normally. There was no statistically significant difference with
of >6 had a higher risk of conversion to open surgery, specifically regards to subjects’ age (p = 0.483), with an average age of 55.20 ±
six times higher risk compared with those with a CLOC score of 17.2 years among those who underwent conversion to open
≤6. This score had a sensitivity of 77.1% and a specificity of 65.4%; cholecystectomy and an average age of 50.93 ± 13.3 years among
thus, this score may be utilized in the clinical settings to accurately those who did not. Based on age-groups, most of the subjects were
4
predict the risk of conversion. Other important issue in laparoscopic 40–69 years and only 11 subjects who were <30 years. Most of the
cholecystectomy is prolonged operative time. Prolonged duration subjects were female (103 subjects, 63.2%).
4
of surgery according to Sutcliffe et al. is an important determinant The indication for laparoscopic cholecystectomy in this study
of overall complication rate, including bile leak, injury to biliary was almost exclusively colicky pain (symptomatic gallstones), which
duct, and longer length-of-stay. Among the proposed risk scoring comprised of 144 cases (88.3%). A total of 146 subjects (89.0%) in
systems, CLOC risk score is the preoperative predictive score that this study also had normal gallbladder wall thickness (<4 mm), and
has been developed according to prospective data with a large a total of 141 subjects (86.5%) did not have dilated common biliary
sample size and has been widely validated. On the other hand, in duct diameter. Based on the ASA classification, a total of 123 subjects
Indonesia, there has been no data and preoperative conversion (75.5%) were ASA class 2. The only variable found to have statistically
risk scoring system. The CLOC risk score may be utilized to reduce significant difference in proportion was dilation of common biliary
the risks of morbidity and mortality associated with conversion to duct (p = 0.010). This result was obtained through Fisher test.
open procedure. The median duration of surgery in this study was 135 (30–105)
Previously, G10 scoring system for predicting bailout procedure minutes, with an interquartile range of 70. Data with regards to
has been validated in Dr Cipto Mangunkusumo Hospital (RSCM). duration of surgery were expressed in the form of median and
However, this scoring system uses intraoperative parameters and interquartile range due to abnormal distribution. There was a
is not specific for predicting conversion to open cholecystectomy. statistically significant difference between the duration of surgery
The CLOC scoring system has the advantage of utilizing and rate of conversion (p < 0.001). The median duration of surgery
preoperative parameters. This system can specifically predict the in the conversion group was 270 (230–300) minutes, compared with
risk of conversion and thus may be utilized for risk estimation and 130 (30–405) minutes in the control group. Detailed information on
preparation for open cholecystectomy if the patient is considered subjects’ characteristics was shown in Table 1.
high-risk. However, in order for this scoring system to be applied
in RSCM, it need to be validated accordingly. RSCM will be the first Association between the CLOC Score and the Rate
hospital to validate this scoring system outside of the center where of Conversion to Open Cholecystectomy
this score was developed. Because the data obtained in this study did not fulfill the criteria
for Chi-square test, Fisher’s exact test were conducted to obtain
the proportion of low-risk (≤6) and high-risk (>6) CLOC score for
MAterIAls And Methods conversion. Among subjects with low-risk CLOC score, 1 (0.8%)
Population underwent conversion, while the remaining 33 subjects (99.2%)
This study is a retrospective study of patients who underwent had straightforward laparoscopic cholecystectomy.
laparoscopic cholecystectomy procedures in RSCM from January There was a statistically significant difference in the rate of
2018 to December 2019 period. Patients with incomplete medical conversion between subjects who had a low-risk CLOC score
records were excluded. Data according to CLOC score variables, and subjects who did not (p = 0.010). The difference in the rate of
including age, sex, indication for surgery, ASA class, gallbladder wall, conversion to open cholecystectomy between those with low-
and common biliary duct diameter were collected. risk score and those with high-risk score was 10.0%. Because the
difference in proportion was less than 20%, clinically there was no
Data Analysis difference between low-risk and high-risk CLOC score in terms of
Data were analyzed using IBM Statistical Package for the Social the rate of conversion in RSCM patients. The slight difference in
Sciences (SPSS) version 20. Data analysis conducted included proportion may be due to the small sample size. The difference in
both descriptive and inferential statistics. Descriptive statistics proportion was shown in Table 2.
were provided in the form of table. The Kolmogorov–Smirnov test
was opted because the number of subjects for this study was >50 Logistic Regression Analysis
patients. Afterwards, bivariate and multivariate statistical analyses Based on the bivariate analysis in Table 1, the variables age, age-
were conducted. Bivariate analysis was conducted using a Chi- group, dilation of common biliary duct diameter, and ASA class
2
square (χ ) test. Alternatives for Chi-square test were Fisher test or had p-values of ≤0.25 and thus may be further included in logistic
Mann–Whitney test. Multivariate analysis was conducted along with regression analysis. On the other hand, the variables sex, indication
logistic regression test to identify the cause-and-effect relationship for surgery, and gallbladder wall thickness all had p-values of
among all the parameters/components of the CLOC scoring system >0.25 and thus were not included in logistic regression analysis.
and the rate of conversion. Calculation of the sensitivity and However, all parameters included in CLOC score theoretically were
specificity of the CLOC scoring system for patients in RSCM were considered important. Logistic regression analysis was performed
conducted using the ROC curve. with backward methods until the regression model was obtained

158 World Journal of Laparoscopic Surgery, Volume 15 Issue 2 (May–August 2022)