Grading operative findings at laparoscopic cholecystectomy- a new scoring system

Cholecystectomy is currently one of the commonest reasons for admission to hospital with an associated mortality of 0.45 to 6% depending on severity of gallbladder disease [11]. It accounts for a significant workflow in gastrointestinal surgery and emergency care [4,12]. Optimising care and care pathways requires an understanding of the underlying disease [13,14]. Not only can the natural history of gallbladder disease vary with patient cohorts but surgical findings can be surprising, with somewhat unexpected degrees of surgical difficulty (or ease) [15]. It is one of the more unpredictable operations in general surgery, due to the variable operative findings. Publications reporting outcomes, including conversion to open surgery, are hard to compare as currently there is no grading or scoring of operative findings at surgery [16,17].

There are some well-reported models of grading and classification systems that have laid the foundation for collaborative research and improved outcomes [18,19]. The importance of disease classification is increasingly recognised. Crandall and colleagues [20] provide a grading system for measuring anatomic severity of several Emergency General Surgery (EGS) diseases based on the American Association for the Surgery of Trauma (AAST) uniform grading system. Grading and scoring surgical conditions provide a uniform tool for reporting disease severity. As many have only been recently developed, they need validation as does the current scoring system.

The aetiology underlying variable outcomes from laparoscopic cholecystectomy is complex in origin, relating to disease severity, surgical experience, and available instrumentation. Laparoscopic cholecystectomy is now the gold standard replacing open cholecystectomy. It is accepted that recovery is delayed, and risk of complications compounded by both delayed emergency cholecystectomy and excessive conversion from laparoscopic to open surgery. Account needs to be taken, however, that a specialist hepatobiliary surgeon may have a lower conversion rate than general surgeons. However, comparisons between surgeons, institutions and published series are currently impossible as the denominator of the severity of cholecystitis is not only not standardized but also rarely reported.

Lal [15] and colleagues suggest that a difficult cholecystectomy is one taking longer that 90 minutes, tearing the gallbladder, spending more that 20 minutes dissecting the gallbladder adhesions, or more than 20 minutes dissecting Calot’s triangle. While time to dissection of Calot’s triangle will vary on surgical skills and level of experience, it will generally be longer in patients with increasing access difficulty, inflammation and adhesions. Predicting a difficult cholecystectomy is possible with some degree of accuracy, using patient demographics, BMI, presence of a palpable gallbladder, and pre-operative ultrasound (US) or computed tomography (CT) findings [8,9]. In addition, previous cholecystitis or lithotripsy has been shown to increase the likelihood of a difficult procedure [21].

With increasing pressure to perform acute index admission laparoscopic cholecystectomy, an intraoperative-based scoring system will potentially allow meaningful comparison of outcomes [22]. In addition it may provide a trigger to prompt earlier conversion or link specific outcomes measures such as bile leaks to specific operative scores.

However, the current scoring system has some limitations. It has not been validated in a large series and has some subjectivity in terms of the percentage of the gallbladder covered by adhesion. Also, it is difficult to objectively define the amount of adhesions from previous abdominal surgery. In addition adhesions may vary in tenacity and vascularity. However these are difficult to define objectively and as such have omitted from the scoring system. It is, however, simple to calculate and provides a score out of ten. Another limitation is that it does not particularly take into account intra-operative bleeding. The actual amount of bleeding is hard to measure objectively outside a clinical trial.

Other international scoring systems have facilitated advances in clinical and research into different areas of surgery [18-20,23]. Some scoring systems, like some of the previously published gallbladder related reports, have focused on prediction of outcomes from clinical and preoperative investigations rather than operative findings.

Vivek et al. [9] recently reported scoring assessment of difficulty in over 300 patients undergoing laparoscopic cholecystectomy and were accurate in predicting the difficulty and need for conversion. Vivek’s grading system, however, is complex using 22 parameters including 4 intra-operative parameters (distended/contracted or inflamed gallbladder, overhanging liver edge, and cirrhosis). Their scoring system has a sensitivity of 85% and specificity of 97.8% with a maximum score of 44, with a score of 9 predicting a difficult procedure. Their grading systems incorporated many other surgical challenges, including ease or difficulty with umbilical port entry, gall bladder grasping, adhesiolysis, or dissection of Calot’s triangle and duct clipping. However, these are objectively difficult to measure and score. The presence of a cholecystoenteric fistula will invariably indicate severe inflammation and complexity inevitably resulting in conversion. While the absence of fistula in our scoring system may be viewed as a limitation, this phenomenon is rare enough, and if encountered intraoperatively, may warrant a maximal difficulty score.

Gupta et al. [8] in a validation of the scoring system proposed by Randhawa and colleagues [24] allocated a score ranging from 0 (easy) to 15 for the very difficult gallbladder. However, Gupta describes very few operative features- only an ultrasonographically thickened (≥4 mm) GB wall, and an impacted stone in their scoring system. Gallbladder wall thickness is easily measured pre-operatively on US and has been widely used in scoring systems [15,25,26]. Intra-operative measurement of thickness, while technically possible, is not practical in day-to-day surgery and has not been incorporated into our scoring system. Classification of cholecystitis such as the Tokyo Consensus [27] are used to help determine outcomes in studies evaluating treatment modalities in cholecystitis defined as the presence of local inflammation (Murphy sign or right upper quadrant mass, or tenderness) and systemic inflammation (temperature >38°C, elevated C-reactive protein [CRP] levels [>5 mg/L] or an elevated white blood cell count >10 000/μL) and imaging findings (gallstone or biliary debris with a gallbladder wall thickness >4 mm , enlarged gallbladder (long-axis diameter >8 cm and short-axis diameter >4 cm), pericholecystic fluid collection, or linear high density areas in the pericholecystic fat tissue. Severe acute calculous cholecystitis (grade III) is defined as being accompanied by dysfunctions in any one of the following organs or systems: cardiovascular dysfunction with hypotension requiring treatment, neurological dysfunction (decreased level of consciousness), respiratory dysfunction (PaO₂/FIO₂ ratio <300), renal dysfunction (oliguria, creatinine > 2.0 mg/dL liver dysfunction (prothrombin time > 3, international normalized ratio > 2) or platelet count <100 000/μL. Moderate acute calculous cholecystitis (grade II) is accompanied by any of the following parameters: white blood cell count greater than 18 000/μL, a palpable tender mass in the right upper abdominal quadrant, duration of complaints for more than 72 hours, or marked local inflammation (gangrenous cholecystitis, pericholecystic abscess, hepatic abscess, biliary peritonitis, or emphysematous cholecystitis). Cases not meeting criteria for severe or moderate acute calculous cholecystitis are classified as mild (grade I). This classification is not surgical based however, and rather broad.

Regimbeau’s [28] open-label, noninferiority, randomized clinical trial utilises these recognised criteria, however, greater emphasis needs to be paid to the actual degree of operative difficulty as this reflects the degree of inflammation and potential for complications. Solomkin [29] rightly emphasizes the importance of evaluating care and outcomes in cholecystitis but we need to go a step further and recognise the importance of documenting the surgical findings to make outcome analysis more meaningful.

The current scoring system is one of the first to outline key operative findings at laparoscopic cholecystectomy. Its validity needs to be tested in future large prospective series before potentially serving as a template for future database and research into patient outcomes.