|Year : 2019 | Volume
| Issue : 1 | Page : 14-19
Preoperative predictors of conversion in elective laparoscopic cholecystectomy
Smita Chauhan, Shakeel Masood, Anshuman Pandey
Department of Surgical Gastroenterology, Ram Manohar Lohia Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
|Date of Web Publication||14-Mar-2019|
Dr. Shakeel Masood
Department of Surgical Gastroenterology, Ram Manohar Lohia Institute of Medical Sciences, Lucknow - 226 010, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
Introduction: Laparoscopic Cholecystectomy, the gold standard for management of gall stone disease, has a conversion rate of 1.6%-20% at different centers. We audited our elective laparoscopic cholecystectomies, to enable preoperative prediction of the probability of conversion.
Method: Retrospective audit of all laparoscopic cholecystectomies from Jan 2013 to March 2017 was done. The cases that required conversion to open cholecystectomy were evaluated for pre- and intraoperative factors responsible for conversion and statistically analyzed using SPSS version 23 [IBM, USA].
Results: 764 patients (mean age 42.9 years) were taken up for laparoscopic cholecystectomies of which 33(4.31%) were converted to open cholecystectomy. The operative factors responsible for conversion were: (1) the presence of dense pericholecystic adhesions (P<0.001), (2) frozen Callot's triangle (P=0.013), (3) unclear anatomy (P=0.002) and iatrogenic injury to CBD (n=2), or bowel (duodenum and colon n=1). Pre-operative factors associated with conversion included age>60y (P=0.032), male sex (P=0.17), history of fever (P<0.032), prior ERCP (P=0.012) and anatomy complicated by cholecystoenteric fistula or Mirrizi's syndrome (P<0.001) Sonographic findings of contracted GB, thick walled GB, and stone impacted at neck of gallbladder were found to have high predictive value for conversion (P<0.001).
Conclusion: Male sex, Age>60years, history of fever with pain, Mirrizi's syndrome, prior ERCP, ultrasound finding of a contracted gallbladder, thick walled gallbladder, and/or stone impaction at neck of gallbladder, significantly predispose to conversion at laparoscopic cholecystectomy. These preoperative factors translate intra-operatively into an unclear anatomy (suggesting that recurrence of inflammation causes increased fibrosis and unclear anatomy at Calot's) predisposing to a higher conversion rate.
Keywords: Age, factors for conversion, laparoscopic cholecystectomy, male gender, Mirrizi's syndrome, open cholecystectomy, prior endoscopic retrograde cholangiopancreatography
|How to cite this article:|
Chauhan S, Masood S, Pandey A. Preoperative predictors of conversion in elective laparoscopic cholecystectomy. Saudi Surg J 2019;7:14-9
| Introduction|| |
Laparoscopic cholecystectomy (LC), the gold standard for the management of gallstone disease, has a conversion rate of 1.6%–20% at different centers. Although conversion does cause the patient an increase in morbidity and hospital stay, the intent of the operating team to prevent the patient from suffering from serious complications such as biliary, vascular, and bowel injuries, by doing a safe open cholecystectomy, is more beneficial for the patient. In order to be statistically more significant and to decrease the preoperative stress of the patient and their family, we audited our elective nonemergency LCs to identify factors that may help in preoperatively predicting the probability of conversion.
| Methods|| |
A retrospective audit of all LCs from January 2013 to March 2017 was done. All cases with preoperative suspicion of carcinoma gallbladder (GB) were excluded from the study. Patients requiring conversion to open cholecystectomy were evaluated for 23 preoperative factors. The operative findings of all patients were audited. Patients were divided into two groups for analysis: LC group and conversion group. For statistical analysis, continuous variables were transformed into categorical variables. The univariate and multiple logistic regression analyses were performed along with the Chi-square test for risk estimation. P < 0.05 was considered statistically significant. Conversion to open cholecystectomy was considered as the dependent variable. The variables that were found significant on univariate analysis were subsequently analyzed by multivariate analysis using a multivariate logistic regression model. Statistical analysis was done using SPSS software version 23 (SPSS version 23 [IBM, USA]).
| Results|| |
Seven hundred and sixty-four patients (539 females and 225 males) were taken up for LC; 33 (4.31%) of them (17 females and 16 males) were converted to open cholecystectomy. The primary reasons for conversion are listed in [Table 1]. The most common reason for conversion was dense pericholecystic adhesion (17 [51.5%]), leading to either nonprogression of surgery or inability to reach the Calot's triangle safely. Frozen Calot's triangle was the second most common reason (6 [18.8%]) for conversion where the degree of fibrosis at the Calot's triangle made it difficult to achieve the critical view of safety. Unclear anatomy at the Calot's triangle due to increased vascularity secondary to collaterals in one case of chronic liver disease (CLD) and inability to find the cystic duct–common bile duct (CBD) junction in two cases of Type 1 Mirrizi's syndrome were the causes of conversion in three cases. Injury to CBD (avulsion of the cystic duct from the CBD and complete transection of the CBD, n = 1 each) was the reason of conversion in two patients – both cases were diagnosed intraoperatively and managed by conversion to open surgery and primary repair over t-tube. Inadvertent bowel injury, cholecystoduodenal fistula, Mirrizi's Type 2 syndrome, and uncontrolled bleeding from the GB bed (n = 1 each) required conversion, while one patient suffering from coronary artery disease was converted due to uncontrolled hypertension on induction of CO2 pneumoperitoneum.
|Table 1: Primary reason for conversion of laparoscopic cholecystectomy to open cholecystectomy (n=33)|
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Preoperative patient characteristics are described in [Table 2]. The mean age of all patients was 42.9 years. In the laparoscopic group (n = 731), there were 522 females and 209 males. In the conversion group (n = 33), there were 17 (3.2%) females and 16 males (7.1%), suggesting an association of conversion with the sex of the patient (P = 0.014). Age >60 years (P = 0.004) was associated with higher conversion rate. Duration of symptoms did not significantly influence conversion. No association was seen with a history of pain or prior jaundice. However, the association of history of fever with pain significantly increased the chances of conversion to open surgery (P = 0.001). Similarly, a history of previous attack of pancreatitis (P < 0.029) or prior endoscopic retrograde cholangiopancreatography (ERCP) (P < 0.001) also significantly influenced the conversion rate. Two of the three patients of Child's A CLD underwent successful LC, while one required conversion for unclear anatomy. This number, however, was too small to attain statistical significance.
|Table 2: Preoperative characteristics of patients in laparoscopic cholecystectomy group and conversion to open cholecystectomy conversion group|
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Previous upper abdominal surgery was found to have significant association with conversion. Sixteen of the 764 (2.1%) patients had previous upper abdominal surgeries. Five of the 33 patients in the conversion group (15.1%) (P < 0.001) had previous upper abdominal surgery, four of which were previous attempts at open cholecystectomy.
Preoperative biliary complications such as GB perforation, cholecystoenteric fistula, or Mirrizi's syndrome were clubbed together in one group for statistical analysis. Three cases with suspected Type I Mirrizi's syndrome were attempted laparoscopically; however, all the three had to be converted to open surgery (intraoperative finding was Type 1 Mirrizi's syndrome in two cases and Type 2 in one case). Nine cases of gallstone disease with cholecystoenteric fistulae (cholecystoduodenal and cholecystocolic) were taken up for lap cholecystectomy and seven required conversion (10/12 = 83.3%). Sixteen cases of GB perforation were taken up for interval LC, out of which two were converted to open surgery (2/16 = 12.5%). This group of biliary complications was thus found to have a statistically significant association for conversion (P < 0.001).
Changes in wall thickness and the physiological status of the GB at sonography, apart from an impacted gallstone, were associated with higher conversion rate (P < 0.001).
Diabetes mellitus, coronary artery disease, chronic obstructive pulmonary disease (COPD), prior history of extra-abdominal or lower abdominal malignancy (e.g., carcinoma ovary and carcinoma cervix), and number of stones in the GB did not demonstrate any association with conversion.
Patient characteristics associated with higher chances of conversion were considered for binary and multiple logistic regression analyses [Table 3]. Variables such as duration of symptom, history of pain, and jaundice that had no association were also adjusted in the multiple logistic regression model. Age of the patient >60 years was three times more likely to have a conversion (adjusted odds ratio [AOR] = 3.1, 95% confidence interval [CI] = 1.10–8.72, P = 0.032) than a younger patient. Males undergoing LC were over three times more susceptible to be converted to open surgery than females (AOR = 3.24, 95% CI = 1.24–8.50, P = 0.017). Patients having a history of fever with pain were 3½ times more prone to conversion to open cholecystectomy than those without (AOR = 3.54, 95% CI = 1.12–11.22, P = 0.032). Patients who had undergone ERCP for CBD clearance before LC had nearly five times more chances of conversion to open cholecystectomy than those who had not (AOR = 4.88, 95% CI = 1.42–16.79, P = 0.012). Patients having a history of previous upper abdominal surgery were as much as 18 times more likely to have a conversion than those without such a history in the past (AOR = 18.65, 95% CI = 3.0–116.11, P = 0.002). Preoperative biliary complication group of (1) Spontaneous localized GB perforation and (2) Mirrizi's syndrome and bilioenteric fistulae was analyzed separately in the multiple logistic regression analysis. GB perforation was not found to be statistically significant in affecting a conversion on multiple logistic regression analysis (AOR = 1.94, 95% CI = 0.28–13.28, P = 0.502), while patients who had Mirrizi's syndrome or a cholecystoenteric fistula had a very high chance of getting converted to an open cholecystectomy (AOR = 842.41, 95% CI = 82.05–8649.32, P < 0.001).
|Table 3: Univariate and multiple logistic regression analyses applied on preoperative characteristics of patients|
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Changes in wall thickness and the physiological status of the GB at sonography, apart from an impacted gallstone, were associated with higher conversion rate (AOR = 11.64, 95% CI = 3.69–36.78, P < 0.001). These preoperative imaging group findings were subsequently analyzed in the following categories separately: (1) contracted GB, (2) diffusely thick-walled GB, (3) irregular thick-walled GB, and (4) stone-impacted at the neck of GB. Of the 196 patients in this group, 27 (81.81% of the 33 open cholecystectomy group) required conversion (P < 0.001). Contracted GB was reported in 110 cases, eight of these cases underwent conversion to open cholecystectomy. Thick-walled GB was reported in a total of 66 cases. Fourteen (42.4% of conversion group) required conversion. Diffuse thick-walled GB was seen in 46 cases (wall thickness >4 mm); 7 (15.21%) of them required conversion. Irregular thick-walled GB was reported in twenty cases; 7 (35.0%) of them required conversion. These twenty patients had been investigated with contrast-enhanced computed tomography abdomen/magnetic resonance cholangiopancreatography serum carcinoembryonic antigen and serum CA19–9 levels. Stone impaction at the neck of GB was reported in twenty cases; five of these were converted to open cholecystectomy (three of them had Mirrizi's syndrome).
A patient who had an ultrasonography (USG) report of changes in wall thickness and/or the physiological status of the GB and/or an impacted gallstone had the following chances of conversion as compared to patients with a normally distended GB on USG: contracted GB four times more (AOR = 4.35, 95% CI = 1.70–11.15, P = 0.002), diffuse thick-walled GB ten times more (AOR = 10.16, 95% CI = 3.69–28.02, P ≤ 0.001), irregular thick-walled GB as much as thirty times more (AOR = 30.41, 95% CI = 9.78–94.50, P < 0.001), and impacted stone at the neck of GB thirteen times more likely (AOR = 13.51, 95% CI = 3.89–46.88, P < 0.001) to have a conversion.
Incidental carcinoma GB was reported in four of the successfully completed LCs – none requiring conversion at the time of index surgery. Overall, 33 (4.3%) cases were reported to have xanthogranulomatous cholecystitis on final histopathology, of which six (18%) were in the group that had required conversion.
| Discussion|| |
Conversion to open surgery is required to avoid bile duct injury, to treat an intraoperative complication (e.g., biliary, vascular, or bowel injury), or due to failure to progress during surgery. The reason may be just one or a combination of these.
Many previous studies have indicated that older age patients (age >60 years) and males are predisposed to have higher rates of conversion of laparoscopic to open cholecystectomy.,,,,,,,,,,,,,,,,, The same was noted in our study. Older age association may be attributed to a longer period of disease and the association of male gender to the increased severity of gallstone disease in men.
Among the clinical variables of significance, the presence of a history of fever with pain was found to be significantly associated with chances of conversion, probably as it signifies repeated attacks of acute inflammation leading to increased fibrosis. Although in our study, only elective, nonemergency cases were included, this particular prior history of acute cholecystitis affecting more conversions is in accordance with previous studies.,,,
Prior upper abdominal surgeries, especially previous attempts at cholecystectomy, increase the degree of fibrosis and other visceral adhesion to GB and supracolic compartment, thereby increasing the difficulty in visualizing the GB bed and Calot's triangle anatomy as well as achieving the critical view of safety.,,
Complication of gallstone disease such as pancreatitis and spontaneous GB perforation that required previous conservative management followed by interval cholecystectomy were found to have increased fibrosis and pericholecystic adhesions, especially along the previous percutaneous drain tract in cases of conservatively managed localized GB perforations, leading to difficult dissection – these were therefore associated with higher chances of conversion as has also been reported by Lee et al. However, they did not act as an independent variable on multivariate analysis. As stated by Ercan, prior ERCP for CBD calculus was also associated with higher chances of conversion. Although Yang et al. in their meta-analysis have not found prior ERCP or gallstone pancreatitis to have significant impact on conversion, our set of patients, possibly because of increased apathy to disease, seek medical assistance much later and hence have a longer and more complicated disease course.
Unlike Kaafarani et al. and others, associated comorbidities such as hypertension, diabetes mellitus, COPD, and coronary artery disease were not found to significantly affect the rate of conversion in our study.,,,
Though CLD is associated with increased difficulty in dissection due to collaterals and noncompliant cirrhotic liver with increased chances of encountering excessive bleeding, we were able to successfully complete LC in two such patients in our study and only one was converted. Due to the small number of these cases, statistical significance could not be established.
Ultrasound finding of thickened GB wall (>4 mm) has been implicated in most studies as a predictive factor for conversion.,,, In our study, we additionally included the findings of contracted GB and stone impacted at the neck of GB in order to increase the sensitivity of imaging as a tool in predicting the likelihood of conversion to open surgery. In our study group, 27 of the 33 patients in the conversion group had one or more of these findings on imaging (P < 0.001).
Among the intraoperative factors that finally were found associated with higher chances for conversion, the most common causes were dense adhesion and frozen Calot's triangle, which were probably a result of the repeated inflammatory attacks as suggested by the preoperative factors. Unclear anatomy, ductal injury, and presence of cholecystoduodenal/cholecystocolic fistula were other causes seen in a small number of cases but with near-total conversion rate.
Most of the confounding risk factors are similar to those reported from other centers,, but some such as history of fever with pain is additionally found responsible in our study. Any or combination of factors associated with repeated inflammation (e.g., fever with pain, pancreatitis, and contracted GB) were predictors of conversion rather than the presence of other comorbidities.
GB cancer was not responsible for any conversion. Incidental carcinoma GB was reported in four of the successfully completed LCs – none requiring conversion at the time of index surgery.
| Conclusion|| |
Male sex, age >60 years, history of fever with pain, Mirrizi's syndrome, prior ERCP, ultrasound finding of a contracted GB, thick-walled GB, and/or stone impaction at the neck of GB significantly predispose to conversion at LC. These preoperative factors translate intraoperatively into an unclear anatomy (suggesting that the intensity, chronicity, and recurrence of inflammation result in increased fibrosis and unclear anatomy at Calot's triangle), predisposing to a higher conversion rate.
We acknowledge the contributions of Dr. Jai Kishun, Assistant Professor from the Department of Biostatistics and Health Informatics, SGPGIMS, Raebareli road, Lucknow, and Dr. Suneed Kumar, Dr. Dinesh Kumar, Dr. Alankar Gupta, Dr. Khalid Noman, and Mr. Pankaj Patel from the Department of Surgical Gastroenterology, Ram Manohar Lohia Institute of Medical Sciences, Lucknow, Uttar Pradesh, India, in data collection and statistical analysis.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3]