The influence of gallbladder function on the symptomatology in gallstone patients, and the outcome after cholecystectomy or expectancy

Laparoscopic cholecystectomy versus conservative management for adults with uncomplicated symptomatic gallstones: the C-GALL RCT

Background

Gallstone disease is a common gastrointestinal disorder in industrialised societies. The prevalence of gallstones in the adult population is estimated to be approximately 10-15%, and around 80% remain asymptomatic. At present, cholecystectomy is the default option for people with symptomatic gallstone disease.

Objectives

To assess the clinical and cost-effectiveness of observation/conservative management compared with laparoscopic cholecystectomy for preventing recurrent symptoms and complications in adults presenting with uncomplicated symptomatic gallstones in secondary care.

Design

Parallel group, multicentre patient randomised superiority pragmatic trial with up to 24 months follow-up and embedded qualitative research. Within-trial cost-utility and 10-year Markov model analyses. Development of a core outcome set for uncomplicated symptomatic gallstone disease.

Setting

Secondary care elective settings.

Participants

Adults with symptomatic uncomplicated gallstone disease referred to a secondary care setting were considered for inclusion.

Interventions

Participants were randomised 1: 1 at clinic to receive either laparoscopic cholecystectomy or observation/conservative management.

Main outcome measures

The primary outcome was quality of life measured by area under the curve over 18 months using the Short Form-36 bodily pain domain. Secondary outcomes included the Otago gallstones' condition-specific questionnaire, Short Form-36 domains (excluding bodily pain), area under the curve over 24 months for Short Form-36 bodily pain domain, persistent symptoms, complications and need for further treatment. No outcomes were blinded to allocation.

Results

Between August 2016 and November 2019, 434 participants were randomised (217 in each group) from 20 United Kingdom centres. By 24 months, 64 (29.5%) in the observation/conservative management group and 153 (70.5%) in the laparoscopic cholecystectomy group had received surgery, median time to surgery of 9.0 months (interquartile range, 5.6-15.0) and 4.7 months (interquartile range 2.6-7.9), respectively. At 18 months, the mean Short Form-36 norm-based bodily pain score was 49.4 (standard deviation 11.7) in the observation/conservative management group and 50.4 (standard deviation 11.6) in the laparoscopic cholecystectomy group. The mean area under the curve over 18 months was 46.8 for both groups with no difference: mean difference -0.0, 95% confidence interval (-1.7 to 1.7); p-value 0.996; n = 203 observation/conservative, n = 205 cholecystectomy. There was no evidence of differences in quality of life, complications or need for further treatment at up to 24 months follow-up. Condition-specific quality of life at 24 months favoured cholecystectomy: mean difference 9.0, 95% confidence interval (4.1 to 14.0), p < 0.001 with a similar pattern for the persistent symptoms score. Within-trial cost-utility analysis found observation/conservative management over 24 months was less costly than cholecystectomy (mean difference -£1033). A non-significant quality-adjusted life-year difference of -0.019 favouring cholecystectomy resulted in an incremental cost-effectiveness ratio of £55,235. The Markov model continued to favour observation/conservative management, but some scenarios reversed the findings due to uncertainties in longer-term quality of life. The core outcome set included 11 critically important outcomes from both patients and healthcare professionals.

Conclusions

The results suggested that in the short term (up to 24 months) observation/conservative management may be a cost-effective use of National Health Service resources in selected patients, but subsequent surgeries in the randomised groups and differences in quality of life beyond 24 months could reverse this finding. Future research should focus on longer-term follow-up data and identification of the cohort of patients that should be routinely offered surgery.

Trial registration

This trial is registered as ISRCTN55215960.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 14/192/71) and is published in full in Health Technology Assessment; Vol. 28, No. 26. See the NIHR Funding and Awards website for further award information.

Effectiveness of conservative management versus laparoscopic cholecystectomy in the prevention of recurrent symptoms and complications in adults with uncomplicated symptomatic gallstone disease (C-GALL trial): pragmatic, multicentre randomised controlled trial

OBJECTIVE

To assess the clinical and cost effectiveness of conservative management compared with laparoscopic cholecystectomy for the prevention of symptoms and complications in adults with uncomplicated symptomatic gallstone disease.

DESIGN

Parallel group, pragmatic randomised, superiority trial.

SETTING

20 secondary care centres in the UK.

PARTICIPANTS

434 adults (>18 years) with uncomplicated symptomatic gallstone disease referred to secondary care, assessed for eligibility between August 2016 and November 2019, and randomly assigned (1:1) to receive conservative management or laparoscopic cholecystectomy.

INTERVENTIONS

Conservative management or surgical removal of the gallbladder.

MAIN OUTCOME MEASURES

The primary patient outcome was quality of life, measured by area under the curve, over 18 months using the short form 36 (SF-36) bodily pain domain, with higher scores (range 0-100) indicating better quality of life. Other outcomes included costs to the NHS, quality adjusted life years (QALYs), and incremental cost effectiveness ratio.

RESULTS

Of 2667 patients assessed for eligibility, 434 were randomised: 217 to the conservative management group and 217 to the laparoscopic cholecystectomy group. By 18 months, 54 (25%) participants in the conservative management arm and 146 (67%) in the cholecystectomy arm had received surgery. The mean SF-36 norm based bodily pain score was 49.4 (standard deviation 11.7) in the conservative management arm and 50.4 (11.6) in the cholecystectomy arm. The SF-36 bodily pain area under the curve up to 18 months did not differ (mean difference 0.0, 95% confidence interval -1.7 to 1.7; P=1.00). Conservative management was less costly (mean difference -£1033, (-$1334; -€1205), 95% credible interval -£1413 to -£632) and QALYs did not differ (mean difference -0.019, 95% credible interval -0.06 to 0.02).

CONCLUSIONS

In the short term (≤18 months), laparoscopic surgery is no more effective than conservative management for adults with uncomplicated symptomatic gallstone disease, and as such conservative management should be considered as an alternative to surgery. From an NHS perspective, conservative management may be cost effective for uncomplicated symptomatic gallstone disease. As costs, complications, and benefits will continue to be incurred in both groups beyond 18 months, future research should focus on longer term follow-up to establish effectiveness and lifetime cost effectiveness and to identify the cohort of patients who should be routinely offered surgery.

TRIAL REGISTRATION

ISRCTN registry ISRCTN55215960.

The Symptomatic Outcomes of Cholecystectomy for Gallstones

Cholecystectomy is the definite treatment for symptomatic gallstones, and rates are rapidly rising. Symptomatic complicated gallstones are generally treated with cholecystectomy, but there is no consensus on the clinical selection of patients with symptomatic uncomplicated gallstones for cholecystectomy. The aim of this review is to describe symptomatic outcomes before versus after cholecystectomy in patients with symptomatic gallstones as reported in prospective clinical studies and to discuss patient selection for cholecystectomy. Following cholecystectomy, resolution of biliary pain is high and reported for 66-100%. Dyspepsia has an intermediate resolution of 41-91% and may co-exist with biliary pain but may also develop following cholecystectomy with an increase of 150%. Diarrhea has a high increase and debuts in 14-17%. Persisting symptoms are mainly determined by preoperative dyspepsia, functional disorders, atypical pain locations, longer duration of symptoms, and poor psychological or physical health. Patient satisfaction following cholecystectomy is high and may reflect symptom alleviation or a change in symptoms. Comparison of symptomatic outcomes in available prospective clinical studies is limited by variations in preoperative symptoms, clinical presentations, and clinical management of post-cholecystectomy symptoms. When selecting patients with biliary pain only in a randomized controlled trial, 30-40% still have persisting pain. Strategies for the selection of patients with symptomatic uncomplicated gallstones based on symptoms alone are exhausted. For the development of a selection strategy, future studies should explore the impact of objective determinants for symptomatic gallstones on pain relief following cholecystectomy.

Outcomes Following an Index Emergency Admission With Cholecystitis: A National Cohort Study

OBJECTIVE

The objective of this study was to evaluate the differences between patients who undergo cholecystectomy following index admission for cholecystitis, and those who are managed nonoperatively.

SUMMARY BACKGROUND DATA

Index emergency cholecystectomy following acute cholecystitis is widely recommended by national guidelines, but its effect on clinical outcomes remains uncertain.

METHODS

Data collected routinely from the Hospital Episode Statistics database (all admissions to National Health Service organizations in England and Wales) were extracted between April 1, 2002 and March 31, 2015. Analyses were limited to patients aged over 18 years with a primary diagnosis of cholecystitis. Exclusions included records with missing or invalid datasets, patients who had previously undergone a cholecystectomy, patients who had died without a cholecystectomy, and those undergoing cholecystectomy for malignancy, pancreatitis, or choledocholithiasis. Patients were grouped as either "no cholecystectomy" where they had never undergone a cholecystectomy following discharge, or "cholecystectomy." The latter group was then subdivided as "emergency cholecystectomy" when cholecystectomy was performed during their index emergency admission, or "interval cholecystectomy" when a cholecystectomy was performed within 12 months following a subsequent (emergency or elective) admission. Propensity Score Matching was used to match emergency and interval cholecystectomy groups. Main outcome measures included 1) One-year total length of hospital stay due to biliary causes following an index emergency admission with cholecystitis. 2) One-year mortality; defined as death occurring within 1 year following the index emergency admission with acute cholecystitis.

RESULTS

Of the 99,139 patients admitted as an emergency with acute cholecystitis, 51.1% (47,626) did not undergo a cholecystectomy within 1 year of index admission. These patients were older, with more comorbidities (Charlson Comorbidity Score ≥ 5 in 23.5% vs. 8.1%, P < 0.001) when compared to patients who did have a cholecystectomy. While all-cause 1-year mortality was higher in the nonoperated versus the operated group (12.2% vs. 2.0%, P < 0.001), gallbladder-related deaths were significantly lower than all other causes of death in the non-operated group (3.3% vs. 8.9%, P < 0.001). Following matching, 1-year total hospital admission time was significantly higher following emergency compared with interval cholecystectomy (17.7 d vs. 13 d, P < 0.001).

CONCLUSIONS

Over 50% of patients in England did not undergo cholecystectomy following index admission for acute cholecystitis. Mortality was higher in the nonoperated group, which was mostly due to non-gallbladder pathologies but total hospital admission time for biliary causes was lower over 12 months. Increasing the numbers of emergency cholecystectomy may risk over-treating patients with acute cholecystitis and increasing their time spent admitted to hospital.

Systematic review and meta-analysis of gallstone disease treatment outcomes in early cholecystectomy versus conservative management/delayed cholecystectomy

Background

The effectiveness of early cholecystectomy for gallstone diseases treatment is uncertain compared with conservative management/delayed cholecystectomy.

Aims

To synthesise treatment outcomes of early cholecystectomy versus conservative management/delayed cholecystectomy in terms of its safety and effectiveness.

Design

We systematically searched randomised control trials investigating the effectiveness of early cholecystectomy compared with conservative management/delayed cholecystectomy. We pooled the risk ratios with a 95% CI, also estimated adjusted number needed to treat to harm.

Results

Of the 40 included studies for systematic review, 39 studies with 4483 patients are included in meta-analysis. Among the risk ratios of gallstone complications, pain (0.38, 0.20 to 0.74), cholangitis (0.52, 0.28 to 0.97) and total biliary complications (0.33, 0.20 to 0.55) are significantly lower with early cholecystectomy. Adjusted number needed to treat to harm of early cholecystectomy compared with conservative management/delayed cholecystectomy are, for pain 12.5 (8.3 to 33.3), biliary pancreatitis >1000 (50–100), common bile duct stones 100 (33.3 to 100), cholangitis (100 (25–100), total biliary complications 5.9 (4.3 to 9.1) and mortality >1000 (100 to100 000).

Conclusions

Early cholecystectomy may result in fewer biliary complications and a reduction in reported abdominal pain than conservative management.

PROSPERO registration number

2020 CRD42020192612.

Patient-specific fluid-structure interaction model of bile flow: comparison between 1-way and 2-way algorithms

Gallbladder disease is one of the most spread pathologies in the world. Despite the number of operations dealing with biliary surgery increases, the number of postoperative complications is also high. The aim of this study is to show the influence of the biliary system pathology on bile flow character and to numerically assess the effect of surgical operation (cholecystectomy) on the fluid dynamics in the extrahepatic biliary tree, and also to reveal the difference between 1-way and 2-way FSI algorithms on the results. Moreover, the bile viscosity and biliary tree geometry influence on the choledynamics were evaluated. Bile velocity, pressure, wall shear stress (WSS), displacements and von Mises stress distributions in the extrahepatic biliary tree are presented, and comparison is made between a healthy and a lithogenic bile. The patient-specific biliary tree model is created using magnetic resonance imaging (MRI) and imported in a commercial finite element analysis software. It is found that in the case of lithogenic bile, velocities have lower magnitude while pressures are higher. Furthermore, stress analysis of the bile ducts shows that the WSS distribution is found mostly prevailing in the common hepatic duct and common bile duct areas. It is shown that when it is necessary to evaluate the bile flow dynamics in urgent medical situations, 1-way analysis is acceptable. Nevertheless, 2-way FSI provides more accurate data, if necessary to evaluate the stress-strain state of bile ducts. The proposed model can be applied to medical practice to reduce the number of post-operative complications.

Protocol for a randomised controlled trial comparing laparoscopic cholecystectomy with observation/conservative management for preventing recurrent symptoms and complications in adults with uncomplicated symptomatic gallstones (C-Gall trial)

BACKGROUND

Gallstone disease (cholelithiasis) is common. In most people it is asymptomatic and does not require treatment, but in about 20% it can become symptomatic, causing pain and other complications requiring medical attention and/or surgery. A proportion of symptomatic people with uncomplicated gallstone disease do not experience further episodes of pain and, therefore, could be treated conservatively. Moreover, surgery carries risks of perioperative and postoperative complications.

METHODS AND ANALYSIS

C-Gall is a pragmatic, multicentre, randomised controlled trial and economic evaluation to assess whether cholecystectomy is cost-effective compared with observation/ conservative management (here after referred to as medical management) at 18 months post-randomisation (with internal pilot).

PRIMARY OUTCOME MEASURE

Patient-reported quality of life (QoL) (36-Item Short Form Survey (SF-36) bodily pain domain) up to 18 months after randomisation.The primary economic outcome is incremental cost per quality-adjusted life year gained at 18 months.

SECONDARY OUTCOME MEASURES

Secondary outcome measures include condition-specific QoL, SF-36 domains, complications, further treatment, persistent symptoms, healthcare resource use, and costs assessed at 18 and 24 months after randomisation. The bodily pain domain of the SF-36 will also be assessed at 24 months after randomisation.A sample size of 430 participants was calculated. Computer-generated 1:1 randomisation was used.The C-Gall Study is currently in follow-up in 20 UK research centres. The first patient was randomised on 1 August 2016, with follow-up to be completed by 30 November 2021.

STATISTICAL ANALYSIS

Statistical analysis of the primary outcome will be intention-to-treat and a per-protocol analysis. The primary outcome, area under the curve (AUC) for the SF-36 bodily pain up to 18 months, will be generated using the Trapezium rule and analysed using linear regression with adjustment for the minimisation variables (recruitment site, sex and age). For the secondary outcome, SF-36 bodily pain, AUC up to 24 months will be analysed in a similar way. Other secondary outcomes will be analysed using generalised linear models with adjustment for minimisation and baseline variables, as appropriate. Statistical significance will be at the two-sided 5% level with corresponding CIs.

ETHICS AND DISSEMINATION

The North of Scotland Research Ethics Committee approved this study (16/NS/0053). The dissemination plans include Health Technology Assessment monograph, international scientific meetings and publications in high-impact, open-access journals.

TRIAL REGISTRATION NUMBER

ISRCTN55215960; pre-results.

Gallbladder function predicts subsequent biliary complications in patients with common bile duct stones after endoscopic treatment?

BACKGROUND

In patients with common bile duct stones (CBDS) and intact gallbladder, further management for the gallbladder after the CBDS clearance is still controversial. The relationship between gallbladder motility and the biliary complications were seldom discussed. Our study is to predict the subsequent biliary complications by gallbladder function test using fatty meal sonography (FMS) in patients with CBDS who had been treated by endoscopic retrograde cholangiopancreatography (ERCP).

METHODS

Patients with an intact gallbladder and CBDS after endoscopic clearance of bile duct were enrolled. Patients received a fatty meal sonography after liver function returned to normal. The fasting volume, residual volume, and gallbladder ejection fraction (GBEF) in FMS were measured. Relationships of patients' characteristics, gallbladder function and recurrent biliary complication were analyzed.

RESULTS

From 2011 to 2014, 118 patients were enrolled; 86 patients had calculus gallbladders, and 32 patients had acalculous gallbladders. After a mean follow- up of 33 months, 23 patients had recurrent biliary complications. Among 86 patients with calculus gallbladder, 15 patients had spontaneous clearance of gallbladder stones; 14 patients received cholecystectomy due to acute cholecystitis or recurrent colic pain with smooth postoperative courses. In the follow up period, six patients died of non-biliary causes. The GBEF is significant reduced in most patients with a calculus gallbladder in spite of stone color. Calculus gallbladder, alcohol drinking and more than one sessions of initial endoscopic treatment were found to be the risk factors of recurrent biliary complication.

CONCLUSIONS

Gallbladder motility function was poorer in patients with a calculus gallbladder, but it cannot predict the recurrent biliary complication. Since spontaneous clearance of gallbladder stone may occur, wait and see policy of gallbladder management after endoscopic treatment of CBDS is appropriate, but regular follow- up in those patients with risk factors for recurrence is necessary.

Clinical effectiveness and cost-effectiveness of cholecystectomy compared with observation/conservative management for preventing recurrent symptoms and complications in adults presenting with uncomplicated symptomatic gallstones or cholecystitis: a systematic review and economic evaluation

BACKGROUND

Approximately 10-15% of the adult population suffer from gallstone disease, cholelithiasis, with more women than men being affected. Cholecystectomy is the treatment of choice for people who present with biliary pain or acute cholecystitis and evidence of gallstones. However, some people do not experience a recurrence after an initial episode of biliary pain or cholecystitis. As most of the current research focuses on the surgical management of the disease, less attention has been dedicated to the consequences of conservative management.

OBJECTIVES

To determine the clinical effectiveness and cost-effectiveness of cholecystectomy compared with observation/conservative management in people presenting with uncomplicated symptomatic gallstones (biliary pain) or cholecystitis.

DATA SOURCES

We searched all major electronic databases (e.g. MEDLINE, EMBASE, Science Citation Index, Bioscience Information Service, Cochrane Central Register of Controlled Trials) from 1980 to September 2012 and we contacted experts in the field.

REVIEW METHODS

Evidence was considered from randomised controlled trials (RCTs) and non-randomised comparative studies that enrolled people with symptomatic gallstone disease (pain attacks only and/or acute cholecystitis). Two reviewers independently extracted data and assessed the risk of bias of included studies. Standard meta-analysis techniques were used to combine results from included studies. A de novo Markov model was developed to assess the cost-effectiveness of the interventions.

RESULTS

Two Norwegian RCTs involving 201 participants were included. Eighty-eight per cent of people randomised to surgery and 45% of people randomised to observation underwent cholecystectomy during the 14-year follow-up period. Participants randomised to observation were significantly more likely to experience gallstone-related complications [risk ratio = 6.69; 95% confidence interval (CI) 1.57 to 28.51; p = 0.01], in particular acute cholecystitis (risk ratio = 9.55; 95% CI 1.25 to 73.27; p = 0.03), and less likely to undergo surgery (risk ratio = 0.50; 95% CI 0.34 to 0.73; p = 0.0004), experience surgery-related complications (risk ratio = 0.36; 95% CI 0.16 to 0.81; p = 0.01) or, more specifically, minor surgery-related complications (risk ratio = 0.11; 95% CI 0.02 to 0.56; p = 0.008) than those randomised to surgery. Fifty-five per cent of people randomised to observation did not require an operation during the 14-year follow-up period and 12% of people randomised to cholecystectomy did not undergo the scheduled operation. The results of the economic evaluation suggest that, on average, the surgery strategy costs £1236 more per patient than the conservative management strategy but was, on average, more effective. An increase in the number of people requiring surgery while treated conservatively corresponded to a reduction in the cost-effectiveness of the conservative strategy. There was uncertainty around some of the parameters used in the economic model.

CONCLUSIONS

The results of this assessment indicate that cholecystectomy is still the treatment of choice for many symptomatic people. However, approximately half of the people in the observation group did not require surgery or suffer complications in the long term indicating that a conservative therapeutic approach may represent a valid alternative to surgery in this group of people. Owing to the dearth of current evidence in the UK setting a large, well-designed, multicentre trial is needed.

STUDY REGISTRATION

The study was registered as PROSPERO CRD42012002817.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Systematic review of the clinical and cost effectiveness of cholecystectomy versus observation/conservative management for uncomplicated symptomatic gallstones or cholecystitis

BACKGROUND

Gallstone disease is a common gastrointestinal disorder in industrialised countries. Although symptoms can be severe, some people can be symptom free for many years after the original attack. Surgery is the current treatment of choice, but evidence suggests that observation is also feasible and safe. We reviewed the evidence on cholecystectomy versus observation for uncomplicated symptomatic gallstones and conducted a cost-effectiveness analysis.

METHODS

We searched six electronic databases (last search April 2014). We included randomised controlled trials (RCTs) or non-randomised comparative studies where adults received either cholecystectomy or observation/conservative management for the first episode of symptomatic gallstone disease (biliary pain or cholecystitis) being considered for surgery in secondary care. Meta-analysis was used to combine results. A de novo Markov model was developed to assess the cost effectiveness of the interventions.

RESULTS

Two RCTs (201 participants) were included. Eighty-eight percent of people randomised to surgery and 45 % of people randomised to observation underwent cholecystectomy during the 14-year follow-up period. Participants randomised to observation were significantly more likely to experience gallstone-related complications (RR = 6.69, 95 % CI = 1.57-28.51, p = 0.01), in particular acute cholecystitis (RR = 9.55, 95 % CI = 1.25-73.27, p = 0.03), and less likely to undergo surgery (RR = 0.50, 95 % CI = 0.34-0.73, p = 0.0004) or experience surgery-related complications (RR = 0.36, 95 % CI = 0.16-0.81, p = 0.01) than those randomised to surgery. Fifty-five percent of people randomised to observation did not require surgery, and 12 % of people randomised to cholecystectomy did not undergo surgery. On average, surgery costs £1,236 more per patient than conservative management, but was more effective.

CONCLUSIONS

Cholecystectomy is the preferred treatment for symptomatic gallstones. However, approximately half the observation group did not require surgery or suffer complications indicating that it may be a valid alternative to surgery. A multicentre trial is needed to establish the effects, safety and cost effectiveness of observation/conservative management relative to cholecystectomy.

Gallbladder function and dynamics of bile flow in asymptomatic gallstone disease

AIM: To investigate the effects of gallbladder stones on motor functions of the gallbladder and the dynamics of bile flow in asymptomatic gallstone disease.

METHODS: Quantitative hepatobiliary scintigraphy was performed to detect the parameters of gallbladder motor function [gallbladder ejection fraction (GBEF), gallbladder visualization time (GBVT), gallbladder time to peak activity (GBT_max), gallbladder half emptying time (GBT_1/2), and transit time of bile to duodenum (TTBD)] in 24 patients with asymptomatic cholelithiasis who were diagnosed incidentally during routine abdominal ultrasonographic examination and 20 healthy subjects with normal gallbladder.

RESULTS: Even though there was no significant difference in the clinical and laboratory parameters between the patient and control groups, all parameters of gallbladder function except TTBD were found to differ significantly between the two groups. GBEF in the patient group was decreased (P = 0.000) and GBVT, GBT_max, GBT_1/2 in the patient group were longer (P = 0.000, P = 0.015, P = 0.001, respectively).

CONCLUSION: Our results showed that even if there were not any clinical and laboratory findings, gallbladder filling and emptying could be impaired in patients with gallstone disease.

Mandatory and optional function tests for biliary disorders

Function tests in gastroenterology and hepatology aim to provide criteria for diagnosis of specific disorders and for prediction of patient responses to therapy. This review focuses on the utility of function tests in the management of gallstone disease and functional biliary disorders. In gallstone disease, function tests may be considered in the selection of candidates for nonsurgical therapy of gallbladder stones only. In cases of suspected functional biliary disorders, experts have advocated the use of classical noninvasive tests such as hepatobiliary scintigraphy. However, unequivocal evidence for their utility in diagnosis or patient selection for invasive treatment is yet to be provided. Recently, more advanced noninvasive tests such as real-time ultrasonography or secretin-stimulated magnetic resonance cholangiopancreaticography have been described. Controlled trials using these novel techniques may provide a rationale for the use of function tests in clinical management of calculous and acalculous biliary diseases, but are currently not available.