Evaluation of Risk Factors Leading to Conversion from Laparoscopic Cholecystectomy to Open Surgery: A Retrospective Controlled Study

Abstract

Background:

Laparoscopic cholecystectomy (LC) is one of the most frequently performed operations in surgical practice. Despite increasing experience and technological advances, conversion to open surgery is still necessary in some cases. Although several studies have identified factors associated with increased risk of conversion, debates continue in the literature. This study aimed to evaluate the factors affecting the risk of conversion to open cholecystectomy.

Materials and Methods:

Patients who underwent surgery for cholelithiasis between 2020 and 2023 were analyzed retrospectively. Patients who underwent open cholecystectomy, those who had cholecystectomy as part of another surgical procedure, and patients with gallbladder malignancy (except incidental cases) were excluded from the study. Patients were analyzed based on demographic, clinical, laboratory, radiological, and histopathological data. This study was registered at ClinicalTrials.gov (NCT06244589).

Results:

A total of 1695 patients were included in the study. The median age was 50 years, and 66.6% of patients were female. Conversion from LC to open surgery occurred in 44 patients (2.6%). Multivariate analysis identified male sex, a history of major abdominal surgery, the need for emergency surgery due to acute cholecystitis, an elevated leukocyte count, and gallbladder wall thickening on abdominal ultrasonography as independent risk factors for conversion to open cholecystectomy.

Conclusion:

Male gender, previous major abdominal surgery, emergency surgery due to acute cholecystitis, high leukocyte count, and gallbladder wall thickening on abdominal ultrasonography are independent risk factors for conversion from LC to open surgery. It should be kept in mind in the treatment of patients planned for LC.

Introduction

Cholelithiasis is a common disorder, and the prevalence has been reported to be approximately 1% in population-based studies.¹ The treatment of symptomatic cholelithiasis is surgery, and laparoscopic cholecystectomy (LC) is the gold standard method.² However, some patients planned for LC may require conversion to open surgery. This is associated with longer hospital stays and increased health care costs. Studies have reported conversion rates ranging from 2–15%. Inability to obtain critical view for safety, intra-abdominal adhesions, and severe acute cholecystitis are the leading factors for conversion to open surgery. Several factors have been associated with an increased risk of conversion, including older age, male gender, emergency surgery, previous abdominal surgery, and history of endoscopic retrograde cholangiopancreatography (ERCP).^3,4 Although some factors related to the risk of conversion to open surgery have been reported, there is no consensus in the literature. In our study, we aimed to evaluate the rate of conversion to open surgery and the factors contributing to this risk by evaluating the cholecystectomies performed in our hospital.

Materials and Methods

Study population

Patients aged 18–95 who underwent surgery for cholelithiasis between 2020 and 2023 were included in the study. Patients who underwent open cholecystectomy, those who had cholecystectomy as part of another surgical procedure, and patients with gallbladder malignancy (except incidental cases) were excluded from the study. Patients were divided into two groups: Conversion cholecystectomy (CC) and the LC group. Patients’ demographic data, American Society of Anesthesiologists (ASA) Physical Status Scores, Charlson Comorbidity Index (CCI), body mass index (BMI), history of acute cholecystitis/pancreatitis, previous abdominal surgery, ERCP history, laboratory, and radiology imaging findings were recorded.^5,6 Appendectomy, caesarean section, and inguinal/umbilical hernia repairs were categorized as minor abdominal surgeries, while other abdominal procedures were classified as major abdominal surgeries. Patients with a history of pancreatitis were scheduled for cholecystectomy either during the same hospitalization or after discharge and were included in the elective cholecystectomy group. Patients with a history of acute cholecystitis were in the emergency or interval cholecystectomy group. The Clavien–Dindo classification was used to evaluate complications.⁷

Outcome measures

The primary outcomes of the study were to determine the conversion rate to open cholecystectomy and the factors affecting this. Secondary outcomes included complication rates and postoperative data.

Surgical technique

In our center, LC is routinely performed using a 4-port technique (two 10 mm and two 5 mm ports). Pneumoperitoneum is created using either the Hasson open technique or a Veress needle based on the surgeon’s preference, followed by insertion of a 10 mm camera port and placement of working ports under direct vision. After an initial exploration of the peritoneal cavity, cholecystectomy is performed. No structures are clipped unless a critical view of safety is achieved. A drain is placed only when clinically indicated, and routine use of drains is avoided. Patients without postoperative complications are usually discharged on the first postoperative day.

When laparoscopic dissection cannot be continued or a critical view for safety cannot be obtained, open surgery is performed. A right subcostal incision is generally used for open surgery.

Ethical approval and trial registration

The study was conducted in accordance with the Declaration of Helsinki and approved by the Şişli Hamidiye Etfal Training and Research Hospital Clinical Research Ethics Committee on January 16, 2024 (Decision No: 2535). Informed consent was obtained from all participants. The study was registered at ClinicalTrials.gov (NCT06244589).

Statistical analysis

Statistical analyses were performed using SPSS (Statistical Package for the Social Sciences) version 25.0 (IBM Corp., Armonk, NY, USA). Categorical data were expressed as numbers and percentages, while continuous data were expressed as mean ± standard deviation or median and interquartile range (IQR), depending on the normality of their distribution. The normality of continuous data was tested using the Shapiro–Wilk test. Chi-square tests (Pearson’s chi-square, Fisher’s exact test, etc.) were used to compare categorical data. The Student’s t-test was used to compare normally distributed continuous data, while the Mann–Whitney U-test was used for nonnormally distributed continuous data. Parameters found to be significant or nearly significant (P < .1) in univariate analysis were included in a multivariate logistic regression analysis. All P-values were two-sided, and results were evaluated at a significance level of P < .05 with a 95% confidence interval.

Results

A total of 1695 patients were included in the study. The median age was 50 years (range: 18–87), and 1129 patients (66.6%) were female. The ASA Physical Status score was 1 in 760 patients (44.8%). The median CCI was 1 (IQR: 0–2), and the median BMI was 27 kg/m² (IQR: 25–30). 351 patients (20.7%) had a history of previous abdominal surgery, and 79 patients (4.6%) had major abdominal surgery. Of the total patients, 985 (58.1%) underwent elective surgery, 99 (5.8%) underwent emergency surgery for acute cholecystitis, and 611 (36%) had interval cholecystectomy after an acute cholecystitis attack. A history of ERCP was noted in 172 patients (10.2%), and 253 patients (14.9%) had a history of pancreatitis. LC was successfully completed in 1651 patients (97.4%), while 44 patients (2.6%) required conversion to open surgery. In the conversion group, the median age was significantly higher (P = .011), the male proportion was higher (P < .001), CCI was increased (P < .001), and the rates of previous abdominal major surgery (P < .001), emergency surgery (P < .001), ERCP history (P < .001), and history of pancreatitis (P = .001) were all significantly higher (Table 1).

Table 1.

Demographic and Clinical Features of the Participants

Variables	All patients(N = 1695)	Laparoscopic cholecystectomy (N = 1651)	Conversion cholecystectomy(N = 44)	P value
Age (years, median, range)	50 (40–60)	50 (40–59)	54 (46–66)	.011^a
Sex (N, %)
Female	1129 (66.6%)	1111 (65.5%)	18 (1.1%)	<.001^b
Male	566 (33.4%)	540 (31.9%)	26 (1.5%)
ASA Physical Status Score
ASA I	760 (44.8%)	744 (43.9%)	16 (0.9%)	.518^b
ASA II	731 (43.1%)	709 (41.8%)	22 (1.3%)
ASA III	204 (12.1%)	198 (11.7%)	6 (0.4%)
CCI (points, median, IQR)	1 (0–2)	1 (0–2)	2 (1–3)	<.001^a
BMI (Kg/m², median, IQR)	27 (25–30)	27 (25–30)	27 (24–30)	.978^a
Previous abdominal surgery (N, %)
No	1344 (79.3%)	1317 (77.7%)	27 (1.6%)	<.001^c
Minor Abdominal Surgery	272 (16.1%)	269 (15.9%)	3 (0.2%)
Major Abdominal Surgery	79 (4.6%)	65 (3.8%)	14 (0.8%)
Type of surgery (N, %)
Elective	985 (58.1%)	979 (57.8%)	6 (0.4%)	<.001^b
Emergent	99 (5.8%)	70 (4.1%)	29 (1.7%)
Interval	611 (36%)	602 (35.5%)	9 (0.5%)
Previous ERCP
No	1521 (89.8%)	1490 (88%)	31 (1.8%)	<.001^b
Yes	172 (10.2%)	159 (9.4%)	13 (0.8%)
Previous pancreatitis
No	1442 (85.1%)	1412 (83.3%)	30 (1.8%)	.001^b
Yes	253 (14.9%)	239 (14.1%)	14 (0.8%)

Mann–Whitney U test.

Chi-square test.

Fisher’s exact test.

All percentages were calculated based on the total patient population (N = 1695).

All P-values less than .05 was bold.

ASA, American Society of Anesthesiologists; CCI, Charlson Comorbidity Index; BMI, body mass index; ERCP, endoscopic retrograde cholangiopancreatography; IQR, ınterquartile range.

The median leukocyte count was 7450/mm³ (IQR: 6410–8895), and the median C-reactive protein (CRP) was 3 g/dL (IQR 1–8). Both leukocyte count and CRP were significantly higher in the CC group (P < .001 and P < .001, respectively). Abdominal ultrasonography revealed gallbladder wall thickening (>3 mm) in 273 patients (16.1%) and pericholecystic fluid in 68 patients (4%). These findings were significantly more common in the CC group (P < .001 and P < .001, respectively) (Table 2).

Table 2.

Laboratory and Radiological Findings

Variables	All patients(N = 1695)	Laparoscopic cholecystectomy (N = 1651)	Conversion cholecystectomy (N = 44)	P value
Leukocyte Counts (mm³, median, IQR)	7450 (6410–8895)	7440 (6390–8770)	11,000 (7875–17,350)	<.001^a
CRP levels (g/dL, median, IQR)	3 (1–8)	3 (1–7)	27 (11–52)	<.001^a
Ultrasonographic findings
Gallbladder wall thickening (>3 mm)
Yes	273 (16.1%)	235 (13.9%)	38 (2.2%)	<.001^b
No	1422 (83.9%)	1416 (83.5%)	6 (0.4%)
Pericholecystic fluid
Yes	68 (4%)	44 (2.6%)	24 (1.4%)	<.001^b
No	1627 (96%)	1607 (94.8%)	20 (1.2%)

Mann–Whitney U test.

Chi-square test.

All percentages were calculated based on the total patient population (N = 1695).

All P-values less than .05 was bold.

CRP, C-reactive protein; IQR, ınterquartile range.

The median length of stay (LOS) was 2 days (IQR: 1–3) for all patients, with a significantly longer LOS in the CC group (p < .001). A total of 52 patients (3.1%) had Clavien–Dindo grade 1 complications, 49 patients (2.9%) had grade two complications, and 28 patients (1.7%) had grade three complications. Bismuth-Strasberg type A biliary injury was identified in 12 patients (all in the LC group), and type E1 injury in 2 patients (all in the CC group). Complication rates were significantly higher in the CC group (P = .001). Incidental gallbladder malignancy was detected in 11 patients (0.6%) on histopathological examination, with no significant difference between the two groups (P = 1) (Table 3).

Table 3.

Postoperative Results

Variables	All patients(N = 1695)	Laparoscopic cholecystectomy (N = 1651)	Conversion cholecystectomy(N = 44)	P value
LOS (days, median, IQR)	2 (1–3)	2 (1–3)	3 (2–4)	<.001^a
Complications (N, %)
No Complications	1566 (92.4%)	1532 (90.4%)	34 (2.0%)	.001^b
Grade 1	52 (3.1%)	46 (2.7%)	6 (0.4%)
Superficial SSI	52 (3.1%)	46 (2.7%)	6 (0.4%)
Grade 2	49 (2.9%)	47 (2.8%)	2 (0.1%)
Superficial SSI (Antibiotherapy)	28 (1.7%)	27 (1.6%)	1 (0.1%)
Atelectasis	11 (0.6%)	10 (0.5%)	1 (0.1%)
Hematoma (Conservative)	10 (0.5%)	10 (0.5%)	0 (0%)
Grade 3	28 (1.7%)	26 (1.5%)	2 (0.1%)
Bleeding (Reoperation)	14 (0.8%)	14 (0.8%)	0 (0%)
Bismuth-Strasberg type A injury	12 (0.7%)	12 (0.7%)	0 (0%)
Bismuth-Strasberg type E1 injury	2 (0.1%)	0 (0%)	2 (0.1%)
Histopathology (N, %)
Benign	1684 (99.4%)	1640 (96.8%)	44 (2.6%)	1.000^b
Malignant	11 (0.6%)	11 (0.6%)	0 (0%)

Mann–Whitney U test.

Fisher’s exact test.

All percentages were calculated based on the total patient population (N = 1695).

All P-values less than .05 was bold.

IQR, ınterquartile range; LOS, length of stay; SSI, surgical site infection.

The parameters that were significant or close to significance (P < .1) in univariate analysis were evaluated using multivariate logistic regression analysis. Male sex (odds ratio [OR]: 4.99, 95% confidence interval [95% CI]: 1.96–12.72, P < .001), previous major abdominal surgery (OR: 12.34, 95% CI: 3.85–39.49, p < .001), emergency surgery due to acute cholecystitis (OR: 7.49, 95% CI: 1.57–35.69, P = .011), increased leukocyte counts (OR: 1.00, 95% CI: 1.000–1.002, P = .048) and gallbladder wall thickening (OR: 15.73, 95% CI: 4.90–50.43, P < .001) were evaluated as independent risk factors for conversion to open surgery (Table 4, Fig. 1, Supplementary Table S1).

FIG. 1.

Receiver operating curve of multivariate logistic regression modelling.

Table 4.

Multivariate Analysis of Factors Affecting Conversion from Laparoscopic Cholecystectomy to Open Surgery

Variables	Odds ratio	Lower (95%CI)	Upper (95%CI)	P value
Age	1.014	0.981	1.047	.401^a
Sex
Male—Female (Ref)	4.995	1.960	12.721	<.001^a
CCI	1.183	0.901	1.550	.225^a
Previous Abdominal Surgery
No (Ref)	1 (Ref)
Minor abdominal surgery	0.433	0.093	2.019	.287^a
Major abdominal surgery	12.342	3.856	39.495	<.001^a
Type of Surgery
Elective	1 (Ref)
Emergent	7.490	1.571	35.692	.011^a
Interval	0.575	0.146	2.261	.429^a
Previous ERCP
Yes—No (Ref)	2.902	0.920	9.151	.069^a
Previous Pancreatitis
Yes—No (Ref)	1.526	0.488	4.761	.467^a
Leukocyte counts	1.000	1.000	1.002	.048^a
CRP levels	0.996	0.987	1.004	.368^a
Gallbladder wall thickening (>3 mm)
Yes—No (Ref)	15.733	4.908	50.431	<.001^a
Pericholecystic fluid
Yes—No (Ref)	2.078	0.491	8.781	.320^a

Binomial logistic regression analysis.

All P-values less than .05 was bold.

95%CI, 95% confidence interval; Ref, reference; CCI, Charlson Comorbidity Index; CRP, C-Reactive Protein; ERCP, endoscopic retrograde cholangiopancreatography.

Discussion

LC is one of the most frequently performed surgical procedures today. However, in some cases, conversion to open surgery is required. In the literature, conversion rates from LC to open surgery vary between 2%–15%. Differences in patient characteristics, surgeon experience, and devices used between centers are factors that may affect conversion rates.^3,4 In our study, the conversion rate was found to be 2.6%.

Several studies evaluating factors that increase the risk of conversion to open surgery during LC have emphasized advanced age and male gender as significant risk factors.^8–11 In our study, advanced age and male gender were associated with a higher risk of conversion in univariate analysis. However, in multivariate analysis, male gender remained an independent risk factor, while the advanced age lost its significance. Patient comorbidities have also been investigated as possible risk factors for conversion to open surgery. A retrospective study by Vaccari et al.¹⁰ reported that an ASA score higher than three increased the risk of conversion. In contrast, our study found no significant effect of ASA score on conversion risk. In addition, CCI was found to be associated with an increased risk of conversion to open surgery in univariate analysis but lost significance in multivariate analysis.

Intra-abdominal adhesions and previous abdominal surgeries are thought to complicate laparoscopic procedures. Al Masri et al.⁸ reported that previous laparotomies increased the risk of conversion to open surgery. In contrast, some studies have indicated that previous abdominal surgery does not significantly affect conversion risk.^9,10 In our study, previous major abdominal surgery was identified as an independent factor that increased the risk of conversion.

There are studies reporting that emergency surgery due to acute cholecystitis is a factor that complicates LC and increases the risk of conversion to open surgery.^3,4 We also observed a higher risk of conversion in patients undergoing emergency surgery for acute cholecystitis. The impact of gallstone-related complications on the difficulty of cholecystectomy is still a matter of debate. Although there are studies reporting an increased risk of conversion to open surgery in patients who underwent ERCP due to choledocholithiasis, there are also studies indicating that there is no relationship between ERCP or pancreatitis history and the conversion rate.^3,12 In our study, a history of ERCP and pancreatitis were significant factors in the univariate analysis but lost their significance in the multivariate analysis.

In a study evaluating preoperative laboratory data, the high leukocyte count and CRP were found to be statistically significant in patients who had a conversion to open surgery.¹³ When our results were examined, it was seen that both leukocyte and CRP levels were significantly higher in cases converted to open surgery in univariate analysis, but only leukocyte count remained significant in multivariate analysis. Abdominal ultrasonography findings are also important parameters in assessing the risk of conversion. Several studies have suggested that gallbladder wall thickening observed on abdominal ultrasonography increases the risk of conversion.^4,9 Our results in both univariate and multivariate analysis are similar to the literature.

There are reports in the literature that CC is associated with a higher rate of complications compared to LC.^14,15 Similarly, we found a higher rate of complications in conversion cases. The relationship between incidental gallbladder cancer and conversion to open surgery is not well established. A study by Silva TS et al.¹⁵ reported a higher rate of conversion in cases of incidental gallbladder cancer. In our study, gallbladder cancer was detected incidentally in 11 patients (0.6%), and since all of them were in the LC group, it did not affect the conversion rate. Larger studies focusing on incidental gallbladder cancer and CC may help clarify this issue.

Patients should be provided with detailed information about all potential situations that may arise during the perioperative period. This also enhances patient compliance. A preoperative strategy meeting involving the anesthesia team, surgical team, and operating room nurse ensures optimal postoperative outcomes and helps prevent potential adverse events. In addition, the use of a preoperative checklist increases surgical safety by verifying that operating room conditions are optimal.^16–18 A preoperative strategy meeting and checklist help the entire team to react quickly and work in coordination during conversion, reducing transition time and ensuring that necessary instruments are prepared. Predictive factors are effective in the management of the patient as well as the operating room conditions and team. In our study, the CCI score was higher in the conversion cholecystectomy group in univariate analysis. It should be anticipated that additional intraoperative and postoperative medical management may be necessary in these patients. Also, conversion was more common in emergency cases. James X Wu et al.¹⁹ reported that nighttime cholecystectomy was associated with an increased conversion to open surgery. Performing acute cholecystectomy during regular working hours, when possible, may help reduce the likelihood of conversion.

The retrospective design and relative medium sample size are the main limitations of our study. However, having an experienced surgical team and a comprehensive evaluation of multiple factors are among its strengths.

Conclusion

Clinical outcomes are better when patients’ treatment and follow-up are planned with predictive factors. Male gender, previous major abdominal surgery, emergency surgery due to acute cholecystitis, high leukocyte count, and gallbladder wall thickening on abdominal ultrasonography are independent risk factors for conversion from LC to open surgery. These will be useful in the perioperative management of patients planned for LC.

Footnotes

Authors’ Contributions

B.D.: Concept; B.D., S.Ö., A.E.T., and M.A.U.: Design; S.Ö. and M.A.U.: Supervision; B.D., S.Ö., A.E.T., and M.A.U.: Materials; B.D.: Data collection and/or processing; B.D., S.Ö., A.E.T., and M.A.U.: Analysis and/or interpretation; B.D.: Literature search; B.D.: Writing; S.Ö., A.E.T., and M.A.U.: Critical review. All authors read and approved the final version of article.

Disclosure Statement

No competing financial interests exist.

Funding Information

No funding was received for this article.

Supplementary Material

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