Intra-Operative Predictors of difficult cholecystectomy and Conversion to Open Cholecystectomy – A New Scoring System

Objective: To evaluate the intra-operative scoring system to predict difficult cholecystectomy and conversion to open surgery. Methods: This descriptive study was conducted from March 2016 to August, 2016 in the Department of Surgery, Shalimar Hospital. The study recruited 120 patients of either gender, age greater than 18 years and indicated for laparoscopic cholecystectomy (LC). Intra-operatively all patients were evaluated using the new scoring system. The scoring system included five aspects; appearance and adhesion of Gall Bladder (GB), distension or contracture degree of GB, ease in access, local or septic complications, and time required for cystic artery and duct identification. The scoring system ranges from 0 to 10, classified as score of <2 being considered easy, 2 to 4 moderate, 5–7 very difficult, and 8 to 10, extreme. Patient demographic data (i.e. age, gender), co-morbidities, intra-operative scores using the scoring system and conversion to open were recorded. The data was analysed using statistical analysis software SPSS (IBM). Results: Among one hundred and twenty participants, sixty seven percent were females and the mean age (years) was 43.05 ± 14.16. Co-morbidities were present in twenty percent patients with eleven diagnosed with diabetes, six with hypertension and five with both hypertension and diabetes. The conversion rate to open surgery was 6.7%. The overall mean intra-operative scores were 3.52 ± 2.23; however significant difference was seen in mean operative score of converted to open and those not converted to open (8.00 ± 0.92 Vs. 3.20 V 1.92; p-value = 0.001). Among eight cases converted to open, three (37.5%) were in very difficult category while five (62.5%) were in extreme category. Moreover, age greater than 40 years and being diabetic were also the risk factors for conversion to open surgery. Conclusion: The new intra-operative scoring system is a valuable assessment tool to predict difficult laparoscopic cholecystectomy and conversion parameters to open surgery and its utility could improve patient's clinical outcome indicated for laparoscopic cholecystectomy.


INTRODUCTION
Acute cholecystitis is a common complication of gall stone disease with reported incidence of 20% in literature. 1 The pathophysiology is secondary bacterial inflammation of the gall bladder as a consequence of the cystic duct obstruction. 2 Cholecystectomy is the commonest operation of the billiary tract and Laparoscopic cholecystectomy (LC) is the standard operative procedure for the treatment of symptomatic gallbladder disease. 3,4 The need for conversion is neither a failure nor a complication but simply a step taken to ensure patient safety and avoid complications. 5 LC is beneficial compared to traditional open cholecystectomy in terms of reduced pain postoperatively, decrease length of hospital stay, and improved and fast recovery of patients. 6 Sometime, the laparoscopic cholecystectomy may pose undue difficulties during access or dissection and it is considered as a "difficult" when safe completion of the laparoscopic procedure cannot be ensured. 7,8 There are numerous preoperative scoring systems proposing preoperative parameters reported for difficult cholecystectomy 9,10 . However there is no operative classification for laparoscopic surgery. Recently, operative grading system for laparoscopic cholecystectomy -a new scoring system, being the first "Operative classifications" was proposed by Surgrue M et al., (2015) 11 to classify the difficult Cholecystectomy from mild to extreme on the basis of intraoperative predicators. The present study was conducted to help us to identify how valid the proposed intra-operative scoring system is to predict conversion of LC to open surgery.

METHODS
This descriptive cross sectional survey was conducted at Department of Surgery, Shalimar Hospital for six months from March 2016 till August 2016. Patients greater than 18 years of age of either gender, presenting with symptomatic gallstones and indicated for laparoscopic cholecystectomy were included in this study. The exclusion criteria were jaundice, malignancy and patients infected with hepatitis B or C. Pre-operative assessment was performed and Standard four port technique was used for LC.
Structured questionnaire was used to record the findings. Demographic data (i.e. age, gender), anthropometric measurements (i.e. weight, height and body mass index), co-morbidities (i.e. diabetes and hypertension) were recorded. Moreover, all patients were evaluated using the new scoring system. 11 The scoring system included five aspects; appearance and adhesion of Gall Bladder (GB), distension or contracture degree of GB, ease in access, local or septic complications, and time required for cystic artery and duct identification. The new operative scoring system is described in Table-I. The scoring system ranges from 0 to 10, classified as score of less than 2 (easy), 2 to 4 (moderate), 5-7 (very difficult), and 8 to 10 (extreme). Importantly, LC converted to Open was recorded.
The study was conducted after the approval from the ethical review committee of Shalimar Hospital. Written informed consent was taken prior to recruitment of participants in the study. Study participants were completely briefed about the procedures of laparoscopic cholecystectomy, possible complications and possibility of conversion of LC to open procedure, purpose of the research, benefits and harms associated with the research. Anonymity and confidentiality of the study participants were maintained throughout the research. Data Analysis: Data was entered and analyzed using SPSS version 21 (IBM). Once the data was entered in the analytical software it was weighted twice for incorrect entries. Qualitative or categorical data (i.e. gender, age categories, co-morbidities, conversion to open etc.) were presented as frequency and percentage while quantitative data (i.e. age, weight, BMI and scores of intra operative scoring system) was presented as mean ± standard deviation. The mean scores of new intra operative scoring system were compared in two independent groups (converted to open as yes or no) using the independent t test. However, the categorical variables were compared in the two groups using chi square statistics. Where the assumptions of chi square were not satisfied Fisher exact test was used. For the inferential statistics p-value < 0.05 was considered significant.

RESULTS
The present study enrolled one hundred and twenty participants indicated for laparoscopic was reported in more than eighty percent of the participants enrolled. Around eighteen percent of participants having diagnosed with co-morbidity, six (5%) were hypertensive, eleven (9.2%) were diabetic and five (4.2%) were both diabetic and hypertensive. Details of the characteristics of the study participants are given in Table-II. Among, one hundred and twenty participants recruited in this study, eight patients (6.7%) were converted to open surgery. Details of the comparison of intra-operative finding using the new scoring classification in patients indicated for laparoscopic surgery converted to open and those who did not are shown in Table- (Table-III). Details of the intra-operative scores and categories classification of the patients enrolled using the new scoring system are shown in Table-

DISCUSSION
The results of the present study highlighted that patients indicated for laparoscopic cholecystectomy having significantly higher mean operative scores were more likely to be converted to open surgery. Moreover, within the operative scoring system, significantly higher proportion of patients with adhesion burying the gall bladder, distended gall bladder, unable to grasp, Stone ≥1 cm impacted in Hartman's Pouch, bile or pus outside gall bladder and time to identify cystic artery and duct > 90 minutes were converted to open. Finally, greater proportion of patients aged greater than 40 years (75%) and around thirty seven percent patients having diabetes were converted to open.
In the present study conducted, among, one hundred and twenty patients, slightly less than seven percent were converted to open surgery. The recent studies conducted have reported the conversion rates varying in the wide range of 1.5-19%. 12,13 In developed health setting the conversion rate has been reportedly low as compared to less developed healthcare setting of developing countries. This may be due to the ease of availability of most modern and latest laparoscopes and improved training and skills of surgeons in the developed countries as against less developed countries. Studies from Pakistan has reported the conversion rate as 8.7%, 3.5% and 6.5%. [14][15][16] Significant differences were found in intra operative scores with patients having converted to open had higher mean score of 8 compared to those not converted having mean score of 3.2. Moreover, significantly high proportion of patients (62%) in extreme category was converted to open. The operative scoring system is good enough for the prediction of conversion to open surgery. The study by Vivek MA et al. 17 reported scoring assessment of difficulty in more than three hundred patients who underwent LC and found the scoring assessment precise and valuable for predicting the difficulty in procedure and early identification of need for conversion. However, the grading system is quite complex as using twenty two parameters that also included four intra-operative parameters (distended/contracted or inflamed GB, hanging liver edge, and cirrhosis). Gupta validating another scoring system proposed by Randhawa and colleagues 18 reported less operative features, only an ultrasonographically thickened (≥4 mm) GB wall, and an impacted stone. 19 Thus, the proposed new operative scoring system is good enough being the first to outline key operative findings at laparoscopic cholecystectomy but its validity needs to be tested in future large prospective series before potentially serving as validated scoring system. Nauman Ahmed et al.