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| ORIGINAL ARTICLE |
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| Year : 2022 | Volume
: 28
| Issue : 2 | Page : 163-168 |
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Validation of a scoring system to predict difficult laparoscopic cholecystectomy
N Saran, Shafy Ali Khan, AA Najeeb, TG Jithu, A Mohamad Safwan, Melvin Varghese, S Shaju, KN Vijayan
Department of General Surgery, KIMSHEALTH Hospital, Thiruvananthapuram, Kerala, India
| Date of Submission | 02-Dec-2022 |
| Date of Decision | 08-Dec-2022 |
| Date of Acceptance | 12-Dec-2022 |
| Date of Web Publication | 30-Jan-2023 |
Correspondence Address:
Dr. N Saran
Department of General Surgery, KIMSHEALTH Hospital, Thiruvananthapuram - 695 029, Kerala
India
 Source of Support: None, Conflict of Interest: None
DOI: 10.4103/ksj.ksj_49_22
Background: Acute calculous cholecystitis is one of the common conditions. The initial radiological investigation of choice is ultrasonography of the abdomen. Cholecystectomy is the definitive treatment for acute cholecystitis. Laparoscopic cholecystectomy is the procedure of choice for acute cholecystitis. Sometimes there is a need for conversion to open cholecystectomy due to intra-abdominal adhesions which make laparoscopic cholecystectomy difficult. Hence, pre-operative prediction of the risk of conversion or difficulty of operation is an important aspect of planning laparoscopic surgery. In our study, we aimed to analyse the various risk factors and to predict the difficulty and degree of difficulty pre-operative lay by the use of a scoring system. Materials and Methods: All 100 patients were evaluated and their clinical and ultrasound parameters were recorded. They received symptomatic treatment with antibiotics and analgesics preoperatively. Following that, they were subjected to laparoscopic cholecystectomy, time taken, bile spillage, stone spillage, injury to duct, artery and conversion to open cholecystectomy were noted. All patients were operated by similarly experienced surgeons. Postoperatively, cases were followed up for any complications and they were discharged on recovery. Results: Receiver operating characteristic curve analysis of pre-operative with an intraoperative score in our study with area = 0.846, P = 0.0005 <0.01 is highly statistically significant at P < 0.01 level. The sensitivity and specificity of the scoring system at score 0–5 for the prediction of easy laparoscopic cholecystectomy are 89.2% and 80.0%, respectively, and the sensitivity and specificity of the scoring system at score 6–10 for the prediction of difficult laparoscopic cholecystectomy are 80.0% and 89.2%, respectively. Conclusion: Our study concludes that the scoring system evaluated is robust, reliable and useful to predict difficult laparoscopic cholecystectomy.
Keywords: Calculus cholecystitis, laparoscopic cholecystectomy, difficult cholecystectomy
How to cite this article:
Saran N, Khan SA, Najeeb A A, Jithu T G, Safwan A M, Varghese M, Shaju S, Vijayan K N. Validation of a scoring system to predict difficult laparoscopic cholecystectomy. Kerala Surg J 2022;28:163-8 |
How to cite this URL:
Saran N, Khan SA, Najeeb A A, Jithu T G, Safwan A M, Varghese M, Shaju S, Vijayan K N. Validation of a scoring system to predict difficult laparoscopic cholecystectomy. Kerala Surg J [serial online] 2022 [cited 2023 Mar 24];28:163-8. Available from: http://www.keralasurgj.com/text.asp?2022/28/2/163/368606 |
| Introduction | |  |
Acute calculous cholecystitis is one of the common conditions which are due to the inflammation of the gall bladder (GB). It occurs most commonly due to obstruction of the cystic duct by gallstones. Sometimes it can occur without underlying stones. They usually present as acute abdominal pain, fever, dyspepsia and vomiting. Blood investigations usually show leucocytosis which may be mild to moderate. The initial radiological investigation of choice for acute abdominal pain is ultrasonography of the abdomen. It has high sensitivity and specificity for diagnosing cholecystitis.[1] The treatment for acute cholecystitis is cholecystectomy. It is the definitive treatment. Early cholecystectomy performed within 72 h of the onset of illness is preferred over delayed cholecystectomy which is performed 6–10 weeks after initial medical treatment. Laparoscopic cholecystectomy is the procedure of choice for acute cholecystitis.[2],[3] Even though laparoscopic cholecystectomy for acute cholecystitis is more tedious and takes a longer duration than elective cholecystectomy for symptomatic cholelithiasis, the laparoscopic approach remains safe and effective even in the setting of acute and severe inflammation. Open cholecystectomy should be kept an option, particularly in difficult cases, or in patients suspected to have prohibitive intra-abdominal adhesions, but it is rarely the primary treatment of choice.[4]
Conversion to open cholecystectomy is associated with prolonged hospital stay and morbidity. Hence pre-operative prediction of the risk of conversion or difficulty of operation is an important aspect in planning laparoscopic surgery. It helps the surgeons to prepare the patient and proper optimisation before surgery. It also helps the patient and bystanders to prepare themselves financially and mentally for complications, prolonged hospital stay and scars which may be cosmetically important in young patients. Hence, a scoring system is valuable in finding the intraoperative difficulty before the surgery. Hence, the purpose of our study is to analyse the various risk factors and to predict the degree of difficulty preoperatively by the use of a scoring system.
| Materials and Methods | | |
The aim of the study was to validate the accuracy of a pre-operative scoring system by Randhawa and Pujahari[5] to predict difficult laparoscopic cholecystectomy. We analysed the various risk factors and to predict the difficulty and degree of difficulty pre-operative laid by the use of a scoring system.
It was a prospective, observational study from January 2020 to June 2021 on all the patients above 18 years admitted to the emergency, general surgery, medical and surgical gastroenterology departments with complaints of abdominal pain and were later diagnosed to have acute calculous cholecystitis by ultrasound. Patients with common bile duct (CBD) calculus, raised alkaline phosphatase, dilated CBD where CBD exploration will be needed, patients with features of obstructive jaundice and gallstone pancreatitis and patients with suspicious GB malignancy were excluded from the study.
Sample size estimation
Prevalence of difficulty = 0.25
Sensitivity = 0.9
Confidence interval = 0.1
= Expected number 100 cases [[Figure 1] – Carley nomogram].[6]
After obtaining informed consent, all patients satisfying the inclusion criteria and those confirmed by ultrasound examination were evaluated with age, sex, body mass index (BMI), abdominal scar whether supraumbilical or infraumbilical, history of (h/o) previous hospitalisation for acute cholecystitis, palpable GB and with ultrasound findings on GB wall thickness, pericholecystic collection and impacted stone. These findings were scored from 0 to 15 and graded as easy, difficult and very difficult as per the score [Figure 1] and [Table 1]. For all patients, an ultrasound abdomen was done by radiologists. All patients received symptomatic treatment with antibiotics and analgesics preoperatively. Following evaluation, patients were subjected to laparoscopic cholecystectomy, time taken, bile spillage, stone spillage, injury to duct, artery and conversion to open cholecystectomy were noted. Then based on the above findings, three scores were given from 0 to 15 and graded as easy, difficult and very difficult [Table 2], [Figure 2]. Then both pre-operative scores and intraoperative scores were compared and validated against the scoring system given by Randhawa and Pujahari [Table 3].[5] All patients were operated by similarly experienced surgeons. Postoperatively cases were followed up for any complications and discharged after recovery.
The data were analysed with IBM SPSS Statistics for Windows, version 23.0. (Armonk,NY, USA: IBM Corp.).To describe the data, descriptive statistics, frequency analysis and percentage analysis were used. To find the significance in categorical data, the Chi-square test was used. The receiver operating characteristic (ROC) curve analysis was used to find the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy on pre-operative with intraoperative score. In both the above statistical tools, the P = 0.05 is considered statistically significant.
| Results | | |
Our study revealed that out of 100 study population, 48.0% (48) were aged ≤50 years and 52.0% (52) were aged >50 years; in gender distribution, 40.0% (40) were female and 60.0% (60) were male. BMI was <25 in 28.0% (28), 25–27.5 in 33.0% (33) and >27.5 in 39.0% (39). In scar distribution, 86.0% (86) had no scar, 13.0% (13) had infraumbilical scar and 1.0% (1) had supra-umbilical scar; In previous hospitalisation for acute cholecystitis, 78.0% (78) had no hospitalisation and 22.0% (22) were hospitalised for acute cholecystitis; In palpable GB, 99.0% (99) had no palpable GB and 1.0% (1) had palpable GB; In GB thickness, 45.0% (44) had normal thickness, 55.0% (55) had thickness more than or equal to 4 mm. In pericholecystic collection, 79.0% (79) had no collection and 21.0% (21) had collection; in impacted stone distribution, 62.0% (62) had no impacted stone and 38.0% (38) had impacted stone; in pre-operative score, 65.0% (65) had a score of 0–5 and 35.0% (35) had a score of 6–10; in intraoperative score, 65.0% had a score of 0–5 and graded easy, 30.0% had a score of 5–10 and graded difficult and 5.0% had a score of 11–15 and graded very difficult.
Comparison between age with intraoperative score by Pearson's Chi-squared test where χ2 = 3.764, P = 0.152 >0.05 which shows no statistically significant association. Comparison between gender with intraoperative score by Pearson's Chi-squared test where χ2 = 0.203, P = 0.903 >0.05 which shows no statistically significant association. Comparison between BMI with intraoperative score by Pearson's Chi-squared test where χ2 = 1.185, P = 0.881 >0.05 which shows no statistically significant association. Comparison between scar with intraoperative score by Pearson's Chi-squared test where χ2 = 5.885, P = 0.208 >0.05 which shows no statistically significant association. Comparison between h/o hospitalisation with intraoperative score by Pearson's Chi-squared test where χ2 = 27.664, P = 0.0005 <0.01 which shows a highly statistically significant association [Figure 3]. | Figure 3: Comparison between h/o hospitalisation with an intraoperative score
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Comparison between palpable GB with intraoperative score by Pearson's Chi-squared test where χ2 = 2.357, P = 0.308 >0.05 which shows no statistically significant association. Comparison between GB thickness with intraoperative score by Pearson's Chi-squared test where χ2 = 7.796, P = 0.020 <0.05 which shows a statistically significant association [Figure 4].
Comparison between pericholecystic collection with intraoperative score by Pearson's Chi-squared test where χ2 = 21.964, P = 0.0005 <0.01 which shows a highly statistically significant association [Figure 5]. | Figure 5: Comparison between pericholecystic collections with an intraoperative score
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Comparison between impacted stone with intraoperative score by Pearson's Chi-squared test where χ2 = 21.542, P = 0.0005 < 0.01 which shows a highly statistically significant association [Figure 6].
Comparison between pre-operative score with intraoperative score by Pearson's Chi-squared test where χ2 = 48.955, P = 0.0005 < 0.01 which shows a highly statistically significant association [Figure 7].
ROC curve analysis of pre-operative score with intraoperative score was area = 0.846, P = 0.0005 < 0.01 which shows highly statistical difference at P < 0.01 level [Figure 8]. | Figure 8: ROC curve analysis of pre-operative with an intraoperative score. ROC: Receiver operating characteristic
Click here to view |
The ROC curve analysis of pre-operative score with intraoperative score – easy was sensitivity (89.2%), specificity (80.0%), PPV (89.2%), NPV (80.0%), accuracy (86.0%), true positive (58), true negative (28), false positive (7) and false negative (7).
The ROC curve analysis of pre-operative score with intraoperative score – difficult was sensitivity (80.0%), specificity (89.2%), PPV (80.0%), NPV (89.2%), accuracy (86.0%), true positive (28), true negative (58), false positive (7) and false negative (7).
| Discussion | | |
Our hospital-based prospective study aimed to validate a scoring system to predict difficult laparoscopic cholecystectomy among 100 patients presenting with acute cholecystitis at our tertiary care centre.
From our study, we found that the sensitivity and specificity of the scoring system at scores 0–5 for the prediction of easy laparoscopic cholecystectomy are 89.2% and 80.0%, respectively, and the sensitivity and specificity of the scoring system at scores 6–10 for prediction of difficult laparoscopic cholecystectomy are 80.0% and 89.2%, respectively. The area under the ROC curve is 0.846. The prediction comes true in 89.2% of easy cases and 80.0% of difficult cases. The study conducted by Randhawa and Pujahari[5] on this scoring method had sensitivity and specificity of 75% and 90.24%, respectively, with positive predictive values for easy and difficult as 88.8% and 92.2% and area under the ROC curve as 0.82. Hence, the scoring system used in our study is more sensitive than the previous study by Randhawa and Pujahari.[5]
A similar study was conducted by Gupta et al.[7] to validate the scoring system by Randhawa and Pujahari[5] had sensitivity and specificity of 95.74% and 73.68%, respectively. The area under the ROC curve was 0.86. Prediction came true in 90% for easy and 88% for difficult cases.
In our study, old age (age >50 years) has not been found as a significant risk factor (P = 0.152) for difficult laparoscopic cholecystectomy. However, it is a significant risk factor for difficult laparoscopic cholecystectomy in studies done by Lee et al.[8] and Hussain.[9] Probably due to adequate pre-operative optimisation and early intervention, it is not a significant factor in our study.
In our study, sex is not a significant risk factor (P = 0.903) in difficult laparoscopic cholecystectomy. Male sex was found to be a significant risk factor in studies done by Hussain,[9] Lein and Huang[10] and Nachnani and Supe.[11]
BMI had no statistical significance (P = 0.881). In a study conducted by Lee et al.,[8] high BMI (>25 kg/m2) was considered a risk factor for difficult laparoscopic cholecystectomy. This may be probably due to the low sample size.
Patients with previous h/o upper or lower abdominal surgery may have adhesions between the viscera or omentum and abdominal wall. Hence, there may be chances of injury to other structures during the insertion of the first port, and the risk of conversion was reported to be higher in studies conducted by Hussain[9] and Nachnani and Supe.[11] In our study, only 13 patients had infraumbilical scar and one patient had supraumbilical scar. They were not found to be a significant risk factor (P = 0.208) for difficult laparoscopic cholecystectomy, probably due to a smaller set of patients with previous surgeries.
Patients requiring hospitalisation for repeated attacks of acute cholecystitis have more chances of difficult laparoscopic cholecystectomy, partial cholecystectomy and conversion to open cholecystectomy, probably due to dense adhesions at the Calot's triangle and GB fossa. In our study, it was considered to be a significant risk factor (P = 0.0005) for predicting difficult laparoscopic cholecystectomy. These cases required more time for the dissection of the Calot's triangle, dissection of GB from the liver bed and bile spillage were there. It was found to be a significant risk factor in studies conducted by Gupta et al.[7] and Bouarfa et al.[12]
Palpable GB is seen in patients with distended GB due to mucocoele or empyema of the GB. It is difficult to catch hold of the fundus of the GB when it is distended; hence, aspiration of the contents is often required. It is time-consuming and there is a chance of spillage of contents into the peritoneal cavity. Palpable GB was found to be a significant factor in a study conducted by Agrawal et al.[13] and Veerank and Togale.[14] Our study had only one patient with a palpable GB. Palpable GB has no significant (P = 0.308) role in predicting difficult laparoscopic cholecystectomy. This may be probably due to early presentation and initial treatment with antibiotics which results in subsiding inflammation, leading to a very less number of patients presenting with a palpable GB.
The thickened GB is found to be a significant factor (P = 0.020) in difficult laparoscopic cholecystectomy in our study, probably due to difficulty in holding the GB and removal of the GB through the port since it is time-consuming and chances of rupture of specimen bag and spillage of contents. It was found to be a significant factor in a study conducted by Veerank and Togale.[14]
In our study, pericholecystic collection has been found to be a significant risk factor (P = 0.0005) in difficult laparoscopic cholecystectomy, probably due to surrounding oedema, omental adhesions and reactive changes which are more prone to bleeding. It was found to be a significant risk factor in a study conducted by Agrawal et al.[13]
In our study, impacted stone has been found to be a significant risk factor (P = 0.0005) for difficult laparoscopic cholecystectomy, probably due to the fact that impacted stone causes distension of the GB and makes dissection difficult because it limits the extent of anatomical definition and makes dissection difficult at the GB bed and Calot's triangle. A study conducted by Veerank and Togale[14] showed a significant association between impacted stone and difficult laparoscopic cholecystectomy.
The conversion rate reported in laparoscopic cholecystectomy is <5%. According to a prospective study conducted by Bingener-Casey et al.,[15] the main cause for conversion was the inability to correctly identify anatomy. Other causes were bleeding, suspected choledocholithiasis and suspected bile duct injury. In our study, only one case is converted to open cholecystectomy due to dense adhesions between the GB, transverse colon, duodenum and omentum. The GB wall could not be separated from the colon. Hence, cholecystectomy was done by the open method. No other reasons were found to be the reason for conversion. Our study excluded patients with suspected choledocholithiasis. Due to advanced techniques and the use of clip applicators, bleeding was not a reason for conversion. In our study, patients had no injury to bile duct.
The limitation of our study was congenital and anatomical variations in the biliary tree and GB such as a short cystic artery, tortuous right hepatic artery (Moynihan's hump or caterpillar hump) and double GB may not be detected by pre-operative imaging modalities. However, they are well-known factors influencing cholecystectomy. However, the inclusion of these variations is beyond the scope of this study and our hospital is a tertiary referral centre. Hence, many of our patients may have received some kind of treatment from another primary or secondary centre, before presenting here, which may influence our clinical and radiological findings. Hence, our study results are more compatible with therapeutic guiding in similar tertiary care centres.
| Conclusion | | |
We conclude that the scoring system evaluated is robust, reliable and useful to predict difficult laparoscopic cholecystectomy. It will help counsel the patients and bystanders preoperatively and it will help the surgeons to prepare for difficulties, prolonged surgeries and conversion. It also helps in educational institutions for senior surgeons to guide the junior doctors to do the surgeries in the initial period of learning curve if preoperatively it is found to be an easy case and it will increase the exposure to the anatomy and make learning easy.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]
[Table 1], [Table 2], [Table 3]
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