A comprehensive predictive scoring method for difficult laparoscopic cholecystectomy.

CONTEXT: Laparoscopic cholecystectomy (LC) is the gold standard cholecystectomy. LC is the most common difficult laparoscopic surgery performed by surgeons today. The factors leading to difficult laparoscopic cholecystectomy can be predicted. AIMS: To develop a scoring method that predicts difficult laparoscopic cholecystectomy. SETTINGS AND
DESIGN: Bidirectional prospective study in a medical college setup.
MATERIALS AND METHODS: Following approval from the institutional ethical committee, cases from the three associated hospitals in a medical college setup, were collected using a detailed proforma stating the parameters of difficulty in laparoscopic cholecystectomy. Study period was between May 10 and June 12. Preoperative, sonographic and intraoperative criteria were considered. STATISTICAL ANALYSIS USED: Chi Square test and Receiver Operater Curve (ROC) analysis.
RESULTS: Total 323 patients were included. On analysis, elderly patients, males, recurrent cholecystitis, obese patients, previous surgery, patients who needed preoperative Endoscopic retrograde cholangiopancreatography (ERCP), abnormal serum hepatic and pancreatic enzyme profiles, distended or contracted gall bladder, intra-peritoneal adhesions, structural anomalies or distortions and the presence of a cirrhotic liver on ultrasonography (USG) were identified as predictors of difficult LC. A scoring system tested against the same sample proved to be effective. A ROC analysis was done with area under receiver operator curve of 0.956. A score above 9 was considered difficult with sensitivity of 85% and specificity of 97.8%.
CONCLUSIONS: This study demonstrates that a scoring system predicting the difficulty in LC is feasible. There is scope for further refinement to make the same less cumbersome and easier to handle. Further studies are warranted in this direction.

INTRODUCTION

Laparoscopic cholecystectomy (LC) since its inception in 1987, has dramatically replaced conventional open cholecystectomy. LC has rapidly become the gold standard for routine gall bladder removal. Management of biliary tract disease has evolved from being a major procedure to a relatively safe and tolerable day care procedure today, offering early return to full activity.

LC though safe and effective, yet can be difficult at times. Various problems faced are difficulty in creating pneumoperitoneum, accessing peritoneal cavity, releasing adhesions, identifying anatomy, anatomical variation and extracting the gall bladder. LC with these problems along with time taken more than normal we considered as difficult.

LC is the most common difficult laparoscopic surgery performed by surgeons all over the world. This study is based on the assumption that difficulty can be predicted and its design is directed towards identification of these predictors.

AIMS AND OBJECTIVES

To identify the predictors of difficulty in laparoscopic cholecystectomy.

To develop a scoring system on the basis of the observation that may be predictive of difficulty.

MATERIALS AND METHODS

The study was conducted in three hospitals in a medical college set up. All patients who underwent LC from 1st May 2010 to 31st October 2012 were included in the study. A detailed proforma was developed to record information regarding patient history, physical examination, laboratory parameters, ultrasonography (USG) findings and intra-operative details (within 5 minutes of putting port).

We collected data prospectively and chi-square test was applied to predictors to calculate the significance of association with individual difficulty parameters. A predictive score was formed retrospectively to predict the difficulty and tested with receiver operator curve (ROC) analysis on the same study population for significance.

Inclusion Criteria

All patients who underwent LC from 1st May 2010 to 31st October 2012 were included in the study.

Exclusion Criteria

Laparoscopic cholecystectomy performed with other laparoscopic intervention in same setting.

Laparoscopic cholecystectomy with Common Bile Duct (CBD) exploration.

Absolute contraindications to LC like cardiovascular, pulmonary disease, coagulopathies and end stage liver disease.

The cases were identified through the proforma stating the parameters of difficulty. Score up to nine was predicted as easy and >9 as difficult.

RESULTS

During the course of this study total 323 laparoscopic cholecystectomies were included.

Pre-operative, USG and intra-operative predictors that were identified beforehand were analysed against the endpoint of difficult cholecystectomy by applying chi square test [Table 1]. Weightage was given to each parameter based on the number of times they were found to be significantly associated with each difficulty criteria ROC analysis done [Figure 1] with area under receiver operator curve of 0.956. A score above 9 was considered difficult with sensitivity of 85% and specificity of 97.8% [Figure 1].

Table 1

Pre-operative, USG and intra-operative parameters analysed against the end point of difficult laparoscopic cholecystectomy

Figure 1

ROC curve

DISCUSSION

In this study, 323 laparoscopic cholecystectomies were included. Pre-operative, USG and intra-operative predictors that were identified beforehand were analysed against the endpoint of difficult cholecystectomy. Weightage was given to each parameter based on the number of times they were found to be significantly associated with each difficulty criteria. Total score of 44 was obtained [Table 2]. The final analysis was done on the same sample to calculate the score above which a difficult LC could be predicted.

Table 2

Details of scoring system

We have given scores as in the following table [Table 2].

A score above 9.0 was found to be associated with difficult cholecystectomy. As the score increases, difficulty level increases.

Difficulties

Umbilical port entry

Difficult umbilical port entry was associated pre-operatively with previous history of upper abdominal surgeries, body mass index (BMI) more than 30 and presence of upper abdominal scars/hernias.

Obesity and the presence of abdominal fat causes obvious difficulty in the placement of the umbilical port as the umbilicus is displaced downwards and there is difficult to identify the umbilical fascia. Nachnani et al.,[1] and Hussain et al.,[2] have found BMI >30 to be significantly associated with difficulty in umbilical port entry and creating pneumoperitoneum.

Upper abdominal surgeries and presence of upper abdominal scars or hernias (indicators of previous upper abdominal surgeries) may cause formation of intra-peritoneal adhesions that may lead to increased probability of injury and bleeding while placement of umbilical port.

Shannon et al.,[3] have found that the presence of upper abdominal surgeries and presence of upper abdominal scars or hernias as being significantly associated with difficulty in umbilical port placement.

Akyurek et al.,[4] in their study found an association with difficult umbilical port entry and intra-operative bleeding and abnormal ductal or arterial anomalies. Our study also reflects the same.

Gall bladder grasping

Difficulty in gall bladder grasping was associated significantly with contracted gall bladder, distended gall bladder

A distended gall bladder or a gall bladder filled with stones is not easily grasped because it tends to slip away. Presence of inflammation around the gall bladder makes the wall friable and oedematous, thus posing problems to grasping.

Singh et al.,[5] in their study have also found significant association of gall bladder grasping difficulty with distended gall bladder and pericholecystic inflammation.

Lal et al.,[6] have identified that presence of large stones in the gall bladder neck leads to distention and difficulty in grasping.

Adhesiolysis and calots triangle dissection

Preoperatively, the need of adhesiolysis was heralded by abnormal Liver function tests (LFT), elevated amylase, age >65 years, male sex, if the attack was recurrent, history of previous surgery, post endoscopic retrograde cholangiopancreatography (ERCP). Intraoperatively, non visualisation of gall bladder, inflamed gallbladder, presence of intraperitoneal adhesions and ductal anomalies.

Calot's triangle difficulty was associated with age >65, male sex, history of previous attacks, post ERCP, abnormal LFT, elevated amylase contracted gall bladder, presence of peri-pancreatic fluid, presence of multiple stones, presence of cirrhosis on ultrasound, non visualisation of the gall bladder, inflamed gall bladder, intra peritoneal adhesions and presence of ductal anomalies.

Increasing age is associated with an increased probability of multiple attacks of cholecystitis and also increased frequency of upper abdominal surgeries. Therefore, there is increased incidence of fibrosis and adhesions in the hepatic hilum. Randhawa et al.,[7] found that age more than 50 years is associated with the same difficulties. Similarly, western studies in the past have implicated age >65 years with difficulty in Calot's triangle dissection and adhesiolysis.

Our results were in concurrence with Nachnani, Supe et al.,[1] who have proposed that male sex is associated with more intense inflammation or fibrosis resulting in denser adhesions thus a more difficult dissection.

Similarly, history of previous attacks, post ERCP status, non visualisation of gall bladder, peri cholecystic and peri-pancreatic fluid are associated with significant inflammatory process that causes difficulty in dissection of the Calot's triangle and adhesiolysis. Ishizaki et al.,[8] in their study have found post ERCP status to be a significant predictor of difficulty in adhesiolysis and Calot's triangle dissection.

Abnormal LFT and elevated amylase signify ongoing hepatitis, cholangitis and pancreatitis that pose difficulty in dissection due to oedema. Alphonat et al.,[9] and Kama et al.,[10] have demonstrated a similar association in their study. They have also obtained elevated total count as a predictor for difficulty but the same association was not obtained in our study probably because of higher cut off values of elevated total count.

Presence of an overhanging liver edge leads to obstruction in the proper visualisation of the gallbladder, thus causing difficulty in Calot's triangle dissection.

Cirrhosis causes distortion of the normal anatomy of the liver and neovascularisation, thus posing problems in retraction of liver and dissection of the Calot's triangle. Palanivelu et al.,[11] in their study, has also found a similar association.

Duct and artery clipping

Difficulty in duct clipping is significantly associated with history of upper abdomen surgery, post ERCP and presence of upper abdomen scars/hernia at preoperative evaluation. The presence of cirrhosis on ultra sound,non visualised gallbladder, presence of intra peritoneal adhesions, presence of ductal anomalies and arterial anomalies were predictive.

Difficulty in cystic artery clipping is associated with non visualised gallbladder, presence of ductal anomalies, presence of arterial anomalies and intra operative bleeding.

Upper abdominal surgeries and cirrhosis of the liver lead to significant fibrosis and anatomical distortion in the area. In this situation, it is difficult to identify and delineate the cystic duct and artery. Thus, there is difficulty in clipping these structures.

The non visualisation of gall bladder may be due to dense pericholecystic adhesions or an intra-hepatic gall bladder. The hepatic artery and duct tend to be more difficult to identify and clip in these situations. Contemporary literatures on the same lines are not available.

The presence of arterial and or ductal anomalies leads to obvious difficulty in artery clipping.

Jongsiri N et al.,[12] have also associated the presence of anatomical variations with difficulty in clipping.

Gall bladder extraction

Difficulty in gallbladder extraction was associated with distended gallbladder and presence of multiple stones. A distended gallbladder or the presence of multiple stones leads to difficulty in the extraction of the specimen through the small incision thus leading to the need to aspirate the gallbladder, extend the epigastric port and the increased probability of gallbladder perforation during these maneuvers. Singh et al.,[5] and Gabriel et al.,[13] also are in concurrence with our findings.

Sex variation

In our study, the presence of male sex was associated significantly with difficulty in adhesiolysis, and Calot's triangle dissection. Further drains were more frequently used in males.

According to Yol S et al.,[14] men with symptomatic gall bladder are more prone to inflammation and fibrosis with the same disease intensity thus leading to difficulty in dissection as is reflected in our study. They obtained higher levels of collagen, hydroxyproline, macrophages, mast cells and eosinophils in gallbladder wall and pericholecystic tissue which might explain the male fibrogenic propensity.

Russel et al.,[15] have suggested that men tend to present late as they pay less attention to subtle symptoms, therefore, may have more advanced disease.

Non visualisation of gallbladder

Gallbladder not being visualised on initial introduction of scope in our study was significantly associated with difficulty in gallbladder grasping, difficulty in adhesiolysis, difficulty in Calot's triangle dissection, difficulty in duct clipping, difficulty in artery clipping, associated significantly with use of drain and use of sutures.

In our study, gallbladder not being visualised on initial introduction of scope was mostly due to dense adhesions around the gallbladder. Adhesions due to severe inflammation causes distortion of anatomy leading to difficult clipping of artery and duct and hence use of sutures.

Advantages and Disadvantages

In this study, more parameters were considered as compared to other.

The predictive score, however, was found to be difficult to calculate because of the large number of predictors. Further, it needs to be validated prospectively in different study populations. The intra-operative predictors were the ones that have the maximum weightage, but those parameters cannot be calculated beforehand.

CONCLUSION

This study demonstrates that a scoring system predicting the difficulty in LC is feasible. There is a need for further prospective study for the validation of this score. There is scope for further refinement to make the same less cumbersome and easier to handle. Further study shall be directed towards the same.

This study was targeted at identifying the possible predictors of difficulty in LC. At the end of this study the following conclusions may be drawn.

Elderly patients are more likely to have a difficult LC.

Females undergo this surgery more frequently but males tend to have a higher number of difficult cases.

Recurrent cholecystitis is a predictor.

Obese patients and those with recurrent cholecystitis tend to have more difficulties during surgery.

Previous surgery predisposes towards difficulties in cholecystectomy.

Patients who needed preoperative ERCP had more chances of having a difficult cholecystectomy.

Abnormal serum hepatic and pancreatic enzyme profiles were associated with difficulty in surgery.

Pre operative USG can predict difficulties during LG.

Features like distended or contracted gallbladder, intra-peritoneal adhesions, structural anomalies or distortions and the presence of a cirrhotic liver are signs that are associated with subsequent difficulties during the surgery.