Gallstones

Published on 11/04/2015 by admin

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Gallstones

Leslie K. Nathanson

Introduction

In the UK it has been estimated from autopsy studies that approximately 12% of men and 24% of women of all ages have gallstones present.¹ The prevalence in North America is comparable to that in the UK, and it is believed that 10–30% of gallstones become symptomatic. There is a high prevalence in native Americans, who have an incidence of 50% in men and 75% in women in the age group 25–44 years, and this points to the importance of genetic factors in the aetiology of gallstones. In the UK more than 40 000 cholecystectomies are performed each year,² whereas in the USA approximately 500 000 operations are performed annually.³ The incidence of common bile duct stones found before or during cholecystectomy is approximately 12%,⁴ indicating that in the UK alone more than 4000 common bile ducts require stone clearance annually.

Composition, formation and risk factors

Gallstones are usually designated as cholesterol stones, mixed stones or pigment stones.⁵ Pure cholesterol and pure pigment stones account for only 20% of gallstones, and mixed stones are considered as variants of cholesterol stones as they usually contain over 50% cholesterol and account for about 80% of gallstones in Western countries. Chemical analysis shows a continuous spectrum of stone composition rather than three mutually exclusive stone types, and 10–20% contain enough calcium to be rendered radio-opaque.

The two most important determinants of gallstone frequency in any population are age and gender; gallstones become more common with increasing age and are at least twice as common in women.⁶ The increased frequency in women becomes manifest at puberty, and an increased risk of gallstones is conferred by parity and by the ingestion of oral contraceptives.⁷ Other factors related to the development of cholesterol gallstones include obesity, ileal disease or resection, cirrhosis, cystic fibrosis, diabetes mellitus, long-term parenteral nutrition, impaired gallbladder emptying, ingestion of clofibrate,⁸ heart transplant,⁹ and periods of dieting on a very low fat diet.¹⁰ A positive family history of previous cholecystectomy also increases the risk of developing symptomatic gallstone disease.¹¹ Increasing evidence is emerging that impaired colonic motility contributes to stone formation, and speculation arises for this as a means of prevention.¹²

Pigmented gallstones are composed mainly of calcium hydrogen bilirubinate, in a polymerised and oxidised form in ‘black’ stones and in unpolymerised form in ‘brown’ stones. Black stones form in sterile gallbladder bile, but brown stones form secondary to stasis and anaerobic infection in any part of the biliary tree (Fig. 10.1).

Figure 10.1 Schematic outline of the pathogenesis of ‘black’ pigmented stones in sterile gallbladder bile (a) and ‘brown’ pigmented stones in an obstructed biliary tree (gallbladder infrequently) infected with a mixed anaerobic microflora derived from the colon (b). Adapted from Vitek L, Carey MC. New pathophysiologic concepts underlying pathogenesis of pigment gallstones. Clin Res Hepatol Gastroenterol 2012; 36(2):122–9.

Black stones form only in the gallbladder due to hyperbilirubinbilia caused by haemolysis of any cause, ineffective erythropoiesis due to vitamin B₁₂ and folate deficiency, and induced enterohepatic cycling of uncojugated bilirubinate.

Brown stones form in any part of the biliary tree from any cause of chronic stasis and anaerobic infection. Anaerobes secrete enzymes that hydrolyse ester and amide linkages in biliary lipids into calcium-sensitive anions that phase separately as insoluble anions or calcium salts. These precipitates deposit on obstructing elements such as small cholesterol crystals, black stones from the gallbladder, parasite eggs and dead worms or flukes. Oriental hepatolithiasis syndrome is the most serious manifestation of brown pigment stone disease.¹³

Presentation

Gallstones present with symptoms related to the site of the gallstones and are therefore considered according to site.

Investigation

The diagnosis of gallstone disease is suspected on clinical grounds but relies on the relevant laboratory or radiological investigations for confirmation. The differentiation between gallstone causes for pain and other acute intra-abdominal disease should include an erect chest radiograph and plain radiograph of the abdomen. Less than 10% of gallstones are radio-opaque and therefore the yield from abdominal radiographs is low. Occasionally, in cases of intestinal obstruction, air is seen in the biliary tree, suggesting a cholecyst–enteric fistula and gallstone ileus.

Blood tests

Liver function tests (LFTs) should be performed routinely in patients with suspected gallstones. Although these may not be affected by the presence of cholecystolithiasis, they may be abnormal in the presence of choledocholithiasis. An isolated increase of unconjugated bilirubin is present in prehepatic jaundice such as is seen with excessive haemolysis. The biochemical picture of hepatic jaundice, as seen with hepatitis, is one of raised conjugated and unconjugated bilirubin, high aspartate (AST) and alanine (ALT) transaminase levels, but associated with a relatively normal or slightly raised alkaline phosphatase (ALP). Posthepatic (obstructive) jaundice is associated with a raised conjugated bilirubin only, high ALP, and normal AST and ALT. In late cases of obstructive jaundice or in acute cholangitis, the transaminase levels will rise as hepatocellular damage proceeds. Minor abnormalities in the LFTs occur with non-obstructing stones in the CBD. These minor abnormalities may prompt the undertaking of an operative cholangiogram at the time of surgery if a selective operative cholangiogram policy is being pursued.¹⁶^,¹⁷

Approximately 60% of patients with CBD stones (including asymptomatic stones) will have one or more abnormal LFTs, although a substantial number of patients with an abnormal LFT will not have CBD stones. Bilirubin, ALP and γ-glutamyl transpeptidase (GGT) are the most sensitive tests routinely used.¹⁸ In the acute situation, a serum amylase or lipase level should also be ascertained to exclude a diagnosis of pancreatitis, and a raised white blood cell count may support a clinical diagnosis of acute cholecystitis.

Ultrasonography

Ultrasound is the investigation used most widely to confirm the diagnosis of cholelithiasis. It is easy to perform, causes little discomfort to the patient, avoids irradiation and potentially toxic contrast media, and may be useful in demonstrating and assessing other structures in the upper abdomen. The gallbladder wall, as well as its contents, can be assessed and this may give additional information useful for planning management. CBD stones may be harder to identify, although the presence of a dilated CBD and small stones within the gallbladder give clues as to their presence. If the gallbladder cannot be identified, the presence of an echogenic focus in the gallbladder area is nearly as specific a finding as that of calculi in a distended gallbladder. With high-quality ultrasound scanning, gallstones should be detected in at least 95% of patients with stones. Its reliability in detecting CBD stones varies between 23% and 80% depending on body habitus and experience of the ultrasonographer.¹⁹

Endoscopic ultrasound (EUS)

Prat et al. have reported EUS with a sensitivity of 93% and specificity of 97% in detecting CBD stones, showing some promise of approaching values achieved by ERCP (89% and 100%).²⁰ EUS has also been reported as more sensitive than the transabdominal approach. Norton and Alderson reported confirmation of gallstone disease in 15 of 44 patients with ‘idiopathic’ pancreatitis who underwent EUS.²¹

Computed tomography (CT)

CT may be more accurate than ultrasound in identifying CBD stones, with a sensitivity of 75% for CBD stones causing obstructive jaundice.²² However, the relatively low rate of gallbladder stone detection may be due, in part, to cholesterol stones being isodense with bile on CT. The newer generation spiral CT and magnetic resonance imaging (MRI) may be better but their potential advantage over abdominal ultrasound scanning is not readily apparent. Spiral CT following intravenous infusion cholangiography has been shown to allow accurate reconstruction of cystic duct/CBD anatomy and providing severe jaundice is not present rivals magnetic resonance cholangiopancreatography (MRCP) in its capacity to outline CBD stones.²³

Radioisotope scanning

Technetium-labelled hydroxy-imino-diacetic acid (HIDA) is excreted in the bile after intravenous injection. It may be useful for demonstrating the patency of the biliary tree or of biliary–enteric anastomoses, but its use with gallstones is limited. Failure to demonstrate a gallbladder due to a blocked cystic duct may assist in the diagnosis of acute cholecystitis but images are too poor to reveal CBD stones. HIDA scanning may be helpful in patients with right upper quarter pain, fever, gallstones and right lower lobe pneumonia. Referred pain and tenderness can give confusing clinical signs, and the presence of a functional gallbladder makes the diagnosis of cholecystitis much less likely. HIDA scanning is of no value in cases of severe jaundice, since the isotope is not excreted into an obstructed system.

Magnetic resonance cholangiopancreatography (MRCP)

Fast image acquisition in a few seconds and improved software have allowed imaging of the biliary and pancreatic tree in enough detail to approach the resolution of ERCP.²⁴ The technique relies on the principle of imaging fluid columns that are static and so give detail of bile and static fluid in the duodenum and stomach. Better images are obtained with dilated ducts, and bile flow can be a source of error in false-positive stone detection. The presence of CBD calculi can be detected with a sensitivity of 95%, specificity of 89% and accuracy of 92%. The ability to detect anatomical variation of the extrahepatic bile ducts is less established.²⁵ Following standard non-invasive tests, Liu et al. stratified suspicion of CBD stones into four categories. Patients at extremely high risk of CBD stone underwent ERCP. Patients at high risk underwent MRCP followed by ERCP if stones were seen. With diagnostic accuracies greater than 90% many patients were spared unnecessary ERCP.²⁶

Percutaneous transhepatic cholangiography (PTC)

PTC is best performed in patients who have a dilated biliary tree, but is not employed routinely in patients with suspected gallstone biliary obstruction. Despite the use of a fine-gauge needle, there is a risk of bile leakage and haemorrhage in patients with abnormal clotting.

Endoscopic retrograde cholangiopancreatography (ERCP)

ERCP is considered the gold standard in preoperative CBD imaging. With direct visualisation of the papilla using a side-viewing duodenoscope, the papilla can be cannulated selectively to provide images of both the pancreatic and common bile ducts. Water-soluble contrast medium is injected to outline the biliary tree, and offers the advantage over other biliary tree imaging techniques of therapeutic intervention with sphincterotomy and stone extraction at the time of examination (Fig. 10.2). The role of ERCP in the management of CBD stones is discussed later in this chapter.

Figure 10.2 (a) A large stone has been demonstrated by endoscopic retrograde cholangiography within the common bile duct. (b) The common bile duct stone has been snared by a Dormia basket ready for extraction.

Management of gallbladder stones

Asymptomatic stones

There has been much debate regarding the need for surgical intervention in patients with asymptomatic gallstones. In one American study, which assessed the natural history of subjects with asymptomatic stones, individuals with gallstones were diagnosed by ultrasound scan on entry to a large university healthcare plan.²⁷ Only 2% of patients with incidentally diagnosed gallstones became symptomatic each year and presented with biliary colic or cholecystitis rather than the more serious complications of jaundice, empyema or cholangitis.²⁷ Only 10% of the asymptomatic patients, followed for a mean of almost 5 years by McSherry and Glenn, developed symptoms, and only 7% required operation.²⁸ Although stones are undoubtedly associated with an increased risk of gallbladder cancer, only one of the 691 gallstone patients followed in this study was found eventually to have an incidental carcinoma at operation, and further data are required to clarify this issue.

Recent Swedish population postcholecystectomy follow-up data after a mean of 15 years revealed a weak increased risk of oesophageal adenocarcinoma with a standardised incidence ratio of 1.29. This is hypothesised to be due to increased oesophageal bile acid exposure.²⁹

Further randomised data have revealed that surgery remains the best treatment for symptomatic gallstones, but conservative management may in selected circumstances be used in the elderly.³⁰

There is no evidence to support interventional treatment of patients with asymptomatic gallstones since natural history studies have shown that symptoms develop at a rate of less than 2% per year.

Non-operative treatments for gallstones

Dissolution

In the early 1970s there was great interest in the use of dissolution agents, principally chenodeoxycholic acid (CDCA), in the treatment of gallstones.³¹ Prerequisites for attempting dissolution therapy were a functioning gallbladder, multiple small stones (which have a greater total surface area for contact with the dissolution agent rather than a smaller number of larger stones) and radiolucency (indicative of pure cholesterol stones without a calcium or pigment matrix to impede dissolution). Success was slow to be achieved in most subjects, usually taking 6–12 months as judged by the disappearance of stones on ultrasound. Side-effects of treatment included abdominal cramps, diarrhoea and occasional LFT abnormalities. Ursodeoxycholate (UDCA) has been shown to be equally effective as CDCA in dissolving gallstones. In patients administered dissolution agents, O’Donnell and Heaton³² found that recurrence rates increased rapidly in the first few years, with rates of 13% at 1 year, 31% at 3 years, 43% at 4 years and 49% at 11 years. Although recurrent stones were readily redissolved, they generally recurred when therapy ceased.

Lithotripsy

Success with lithotripsy for renal stones led to the use of the same techniques for gallbladder stones. Early lithotripters, with immersion in large water baths, were soon succeeded by smaller devices with a limited area of contact via a water-filled cushion. Biliary anatomy, however, did not lend itself to a repeat of the success observed with renal stones. The tidal flow of bile into and out of the gallbladder, along with the presence of multiple gallstones, were factors that contributed to the failure of the technique. Ahmed et al.³³ reported that 45% of patients undergoing lithotripsy required subsequent cholecystectomy. Lithotripsy has therefore been retained only for the management of ductal stones resistant to endoscopic removal.³⁴

The potential role of oral dissolution therapy and lithotripsy has been superseded by the advent of laparoscopic cholecystectomy.

Operative treatment of gallbladder stones

Open cholecystectomy

The operative mortality of open cholecystectomy for cholelithiasis had fallen in the years before the introduction of laparoscopic surgery, with many series reporting operative mortality rates of less than 1%.³⁵ Common duct exploration was regarded as increasing the risk of open cholecystectomy by four- to eight-fold.³⁶ In a comparative study between a North American and a European centre, 12–14% of patients developed complications, and the bile duct was explored in 8.6% of the patients in Toronto as opposed to 17.9% in Geneva, the incidences of positive exploration being 61% and 73%, respectively. Factors increasing the risk of postoperative mortality were advancing age, acute admission, admission to hospital within 3 months of the index admission, and the number of discharge diagnoses.³⁶ Only 18% of postoperative deaths in this study were related to the gallstone disease or the surgery, with underlying cardiovascular or respiratory disease contributing to 48% of deaths.

There has been considerable uncertainty regarding the true incidence of bile duct injury at open cholecystectomy, and the surveys available cite figures of one injury per 300–1000 operations.³⁷ At cholecystectomy, injury results from imprecise dissection and inadequate demonstration of the anatomical structures.³⁸ Although some patients do have anatomical anomalies or pathological changes that increase the risk of duct injury, it is noteworthy that in the extensive Swedish review, the patients most at risk appeared to be young, slim females who had not undergone previous surgery.³⁷

In a detailed analysis of a consecutive group of patients undergoing cholecystectomy for presumed biliary pain in a District General Hospital between 1980 and 1985, Bates et al.³⁹ compared the outcome of an age- and sex-matched control group of surgical patients without gallstone disease. Flatulent dyspepsia was more frequent in gallstone patients but operation markedly reduced these symptoms to an incidence almost identical to that of the control group. However, within 1 year of cholecystectomy, no less than 34% of patients still suffered some abdominal pain and none of the 35 patients referred back to hospital for investigation had evidence of retained ductal stones. Multivariate analysis showed that preoperative flatulence and long durations of attacks of pain were risk factors for postoperative dissatisfaction.

Given that the basis for symptoms before cholecystectomy often remains uncertain, it is evident that a substantial number of patients continue to experience problems after operation.

Mini-laparotomy cholecystectomy

In the few years before the advent of laparoscopic cholecystectomy, there had been a resurgence of interest in open cholecystectomy through a small incision, the so-called mini-laparotomy cholecystectomy, in an effort to reduce the trauma of open surgery.

There have been few controlled trials; of those that have been performed, one showed laparoscopic cholecystectomy to be superior and the other showed mini-laparotomy cholecystectomy as superior.⁴⁰^,⁴¹ The most recent randomised trial has again confirmed a smoother convalescence for laparoscopic cholecystectomy, although operating times remained longer.⁴²

The technique relies on retractors to provide exposure for a fundus-first cholecystectomy carried out without the surgeon’s hands entering the abdominal cavity. Cholangiography is possible but is not performed in most reports of the technique. The author’s limited first-hand experience of the technique has not persuaded him that the view of the cystic duct/CBD junction is comparable to that achieved by laparoscopic cholecystectomy. The true incidence of bile duct injury with this technique is unknown and cannot be equated to the open era of large incisions.

There is no evidence to support the routine use of mini-cholecystectomy in the treatment of symptomatic gallstone disease.

Laparoscopic cholecystectomy

Despite the paucity of randomised controlled trials, enthusiasm for the technique of laparoscopic cholecystectomy continues unabated, driven predominantly by patient satisfaction, with less pain and an earlier return to normal activities. Surgeons are attracted by the excellent view of the gallbladder and biliary tree afforded by the laparoscope, and health providers and purchasers are attracted by the short hospital stay, which offers significant cost savings.

Symptomatic gallstones: The laparoscopic procedure can be offered to all patients with symptomatic gallstones, providing their cardiorespiratory status does not preclude laparoscopy. Of all patients presenting for operation, 95% can be completed successfully by laparoscopic means. Obesity, acute inflammation, adhesions and previous abdominal surgery do not usually prevent a laparoscopic cholecystectomy, but may require some adaptations of technique to complete the procedure.43–51 Techniques of laparoscopic cholecystectomy have been well described previously,⁴³^,⁴⁴ including cases performed under regional anaesthesia in patients with chronic pulmonary disease.⁴⁵ Laparoscopic cholecystectomy has been widely reported in pregnancy⁴⁶ and in patients with cirrhosis.⁴⁷ In a substantial audit of seven European centres,⁴³^,⁴⁴ 96% of procedures were completed successfully in the 1236 patients and only four bile duct injuries were reported. There were no postoperative deaths, median hospital stay was 3 days and the median return to normal activities was only 11 days.

Acute cholecystitis: Fears that laparoscopic cholecystectomy in the management of acute cholecystitis could carry an unacceptable risk of disseminating infection or of perpetrating an injury to the bile duct appear unfounded.⁵¹ Several large series report success and safety with this procedure, although the incidence of bile duct injury and conversion to open operation remain slightly higher.⁵² In difficult cases, improvement in the exposure of Calot’s triangle may require additional or different positioning of the laparoscopic cannulae, the use of oblique viewing telescopes and placement of endoscopic retractors. Decompression of a distended or inflamed gallbladder may also improve access.

Complications: The mortality rate in a good-risk patient undergoing elective operation is less than 1% and operative risks usually arise from comorbid conditions. The laparoscopic technique is associated with lower wound infection rates than open surgery.⁵³ Furthermore, a recent meta-analysis has shown that antibiotic prophylaxis is not warranted in low-risk patients undergoing laparoscopic cholecystectomy.⁵⁴

Day-case laparoscopic cholecystectomy: Worldwide, laparoscopic cholecystectomy is being performed in the day-case setting with good preoperative patient selection, improved techniques, and improved postoperative control of pain, nausea and vomiting.⁵⁵

Needlescopic cholecystectomy: This technique has been described using 2- and 3-mm instruments and a 3-mm laparoscope. A randomised trial has shown less pain and smaller scars when this technique was used in patients with chronic cholecystitis.⁵⁶

Evolution of technical aspects of multiport exposure, decreasing port sizes and instrumentation continues. There is currently no evidence of a benefit for single-incision laparoscopic port techniques,⁵⁷ with impaired ergonomic performance and probable increased incisional hernia rate.

Bile duct injury: Anxieties regarding an increased incidence of bile duct injury with the introduction of laparoscopic cholecystectomy have not been substantiated by multicentre studies from Europe ⁴⁸ and the USA,⁴⁹ with a reported incidence of injury to the CBD of 1 in 200–300 cases. In a study in the West of Scotland, a prospective audit of laparoscopic cholecystectomy was undertaken.⁵⁸ A total of 5913 laparoscopic cholecystectomies were undertaken by 48 surgeons, and 37 laparoscopic bile duct injuries were reported. Major bile duct injuries were defined as those where laceration to more than 25% of the bile duct diameter occurred, where the common hepatic duct or CBD was transected, or in those instances when a bile duct stricture developed in the postoperative period. Of the 37 injuries, 20 were classified in this way, giving an incidence of 0.3%. Delayed identification of bile duct injury occurred in 19 patients and, although it was noted by the author that cholangiography did not play a part in the identification of bile duct injuries, it was noteworthy that imaging was used in only 8.8% of all laparoscopic procedures. During the course of this 5-year study, the annual incidence of bile duct injury peaked at 0.8% in the third year but had fallen to 0.4% in the final year of the audit. A meta-analysis of more than 100 000 cases reported an injury rate of 0.5%.⁵⁹ Archer et al. emphasised the importance of supervised surgical training to allow attenuation of the trainee surgeon’s learning curve by the experience of his/her proctoring surgeon. The importance of cholangiography in the early detection of bile duct injury was also emphasised.⁶⁰ Way et al. analysed bile duct injuries from a cognitive psychological perspective and concluded that errors that led to bile duct injury stemmed from anatomical misperceptions as opposed to errors of skill or judgment (Fig. 10.3). This analysis concluded with a list of rules to help prevent injuries.⁶¹

Figure 10.3 The ‘classical’ laparoscopic bile duct injury. (a) The common duct is misidentified as the cystic duct and is doubly clipped. (b) The common duct is then divided. (c) The gallbladder is retracted to the right, stretching the common hepatic duct and placing it in contact with the gallbladder. This is identified as an accessory duct and double clipped. (d) A high transection of the common hepatic duct results in the excision of most of the extrahepatic biliary tree.

Cholecystostomy

For patients whose symptoms of acute cholecystitis did not settle in the past, cholecystostomy was often undertaken in those cases where open cholecystectomy was thought to carry an unacceptable risk of injury to the biliary tree. The procedure could be undertaken under local anaesthesia and, following decompression of the gallbladder and stone removal, a drain could be left in situ. With the demonstration that acute cholecystectomy could be undertaken safely,⁵² cholecystostomy has become an infrequent surgical procedure. The technique now is most often undertaken percutaneously under ultrasound or CT guidance and is most used in the frail patient with cardiorespiratory instability requiring time to control or when anticoagulation precludes surgery. It may rarely be of value during a difficult laparoscopic cholecystectomy when the risk of conversion to an open procedure may be considered unacceptable. In such instances, a drain can be inserted through one of the 5-mm cannulae, which can be introduced directly into the gallbladder by reinsertion of a trocar.

Subtotal cholecystectomy

This is another strategy to consider if dense fibrosis or large vessels are present in the area of Calot’s triangle and the cystic duct is clearly identified and confirmed by cholecystogram. The cystic duct is ligated and excision of the gallbladder is undertaken, leaving its posterior wall intact on the liver. This situation probably arises most in those patients with cirrhosis and portal hypertension.

Laparoscopic cholecystectomy is associated with less pain, shorter hospital stay, faster return to normal activity and less abdominal scarring than open surgery, and is therefore preferred to open surgery in the management of symptomatic gallstone disease.⁶²

Intraoperative cholangiography (IOC)

The debate over the potential benefit of operative cholangiography has spanned the open and laparoscopic eras.

Routine IOC: Many surgeons who had previously performed the technique routinely at open cholecystectomy abandoned cholangiography during laparoscopic cholecystectomy, since it was thought to be too difficult to undertake. In a large population-based study in Western Australia, Fletcher et al.⁶³ concluded that operative cholangiography had a protective effect for complications of cholecystectomy. In a large study of over 1.5 million Medicare patients undergoing cholecystectomy, Flum et al.⁶⁴ demonstrated that surgeons performing operative cholangiography routinely had a lower rate of bile duct injuries than those who did not, and this difference disappeared when IOC was not used. The author believes that operative cholangiography has an important role in laparoscopic cholecystectomy, not only to detect CBD stones but also to confirm, beyond doubt, the anatomy of the biliary tree, since the severity of bile duct injury appears far greater in laparoscopic surgery. The addition of cholangiography to the total dissection time of laparoscopic cholecystectomy is relatively short. On the basis that the time to learn operative cholangiography is not during the management of a difficult case, it is recommended that it should be performed as a routine but should not be seen as a substitute for careful dissection of the infundibulum of the gallbladder and the cystic duct close to the gallbladder. By dissecting these structures both anteriorly and posteriorly, the gallbladder is displaced (sometimes called the ‘flag’ technique, or ‘critical view’) to enable the surgeon to see behind the gallbladder and thus minimise the risk of injury to the portal structures. Routine IOC also improves the surgeon’s skills to enable successful transcystic exploration of the CBD.

Selective IOC: There are data supporting a selective approach to IOC at open ¹⁷ and laparoscopic cholecystectomy.⁶⁵ Unsuspected stones on routine cholangiography at laparoscopic cholecystectomy occurred in only 2.9%, and residual CBD stones causing symptoms in patients not undergoing routine cholangiography were found in only 0.30%. The strength of any selective policy for IOC will depend on the predictive values of preoperative investigations. Numerous studies have examined risk factors for choledocholithiasis but, from multivariate analysis, it would appear that an increased diameter of the CBD and the presence of multiple (> 10) gallstones are the only significant independent indicators.¹⁷

Bile duct injury

The principal cause of damage is due to misidentification of the CBD as the cystic duct. As dissection proceeds an ‘accessory duct’ (in reality the common hepatic duct) is visualised, clipped and divided, resulting in resection of most of the extrahepatic biliary tree (Fig. 10.3). Operative cholangiography adds to the certainty that the cannula is in the cystic duct. If only the distal biliary tree is filled, the surgeon is alerted to the error before any duct is completely divided. Although critics of operative cholangiography will argue that the CBD has been injured by the incision through which the cholangiogram catheter is introduced, the injury at this point is recoverable, either by direct suture or insertion of a T-tube (Fig. 10.4). In the rarer situation when the cystic duct arises from the right hepatic duct, and dissection has not progressed correctly, cholangiography identifies such anomalies and helps to avert more major injury (Fig. 10.5).

Figure 10.4 (a) The small-diameter common bile duct has been mistaken for the cystic duct. Only the distal common bile duct and duodenum are shown, with no proximal filling of the ducts. Recognition of the error at this stage averts a major injury to the common duct. (b) After further dissection, the cystic duct was identified and a T-tube placed in the incision in the common duct. A subsequent T-tube cholangiogram confirms the normal anatomy, and laparoscopic cholecystectomy was completed successfully.

Figure 10.5 (a) During what appeared to be a very straightforward laparoscopic cholecystectomy, the routine operative cholangiogram showed only the right hepatic duct and right hepatic biliary tree. (b) Repositioning of the catheter and the LigaClip showed the remainder of the biliary tree and made clear that the structure initially thought to be the cystic duct was the distal right hepatic duct below an anomalous origin of the cystic duct.

Laparoscopic ultrasound (LUS)

The emergence of ultrasound probes that can be passed down the laparoscopic ports has further improved the accurate measurement of CBD diameter, as well as the stone load within the gallbladder. Both mechanical sectoral and linear array laparoscopic ultrasound probes have been shown to be as useful as cholangiography in the detection of CBD stones.⁶⁶^,⁶⁷ LUS is less invasive, less time-consuming, allows less radiation exposure and has similar failure rates to IOC when performed in well-trained hands. In a large series, the common hepatic duct and the CBD were identified in 93% and 99% of cases, respectively. Sensitivity and specificity for identifying bile duct stones were 92% and 100%, respectively. A normal CBD diameter at LUS was also an excellent negative predictor of CBD stones.⁶⁸ The same authors later concluded that LUS could replace IOC.⁶⁹ Others feel IOC and LUS should be seen as complementary tests rather than competitive.⁷⁰ LUS may facilitate a policy of selective cholangiography. Despite reports of accurate identification of anatomy it remains to be seen whether this will translate to prevention of bile duct injury. A cost benefit also remains to be demonstrated, given the capital outlay for the equipment.

The use of intraoperative cholangiography allows detection of CBD stones during cholecystectomy and when interpreted appropriately is associated with a lower risk of CBD injury.

Management of common bile duct stones

The natural history of a given CBD stone remains difficult to predict. In a prospective study of 1000 cases of symptomatic gallstones it was found that 73% of cases that presented with features suggestive of CBD stones had no CBD stone at the time of operation and were therefore considered to have passed the stone spontaneously. Cases of cholangitis or jaundice were less likely to pass stones spontaneously.⁷¹

Primary bile duct stones form within the CBD, usually due to ampullary stenosis, diverticula or impaired bile duct motility. Management of these stones will often require choledochojejunostomy, depending on the circumstances and patient age.⁷²^,⁷³ Treatment of primary duct stones with choledochotomy and T-tube drainage alone is associated with recurrence rates up to 41%.⁷⁴ Laparoscopic choledochoduodenostomy remains an option for the advanced laparoscopic surgeon,⁷⁵^,⁷⁶ although there may be concerns regarding the longer-term consequences of bilioenteric reflux.

Secondary bile duct stones are stones that originate within the gallbladder and are found in the CBD prior to, at the time of, or within 2 years of cholecystectomy. Approximately 12% of patients undergoing surgery for symptomatic gallbladder stones will also have stones in the CBD. More than 90% of these patients will have preoperative indications such as a history of jaundice or pancreatitis or abnormal LFTs, but 5–10% have no indication of stones in the bile duct other than a positive finding (filling defect, absence of filling of the terminal segment of the common duct, delay or absence of flow into the duodenum) on the perioperative cholangiogram.

The best management of CBD stones is still a matter of debate.⁷⁷ Discussion of different practices is presented here in the order the author considers most practical, and a suggested algorithm is presented.

Laparoscopic transcystic common bile duct exploration

Laparoscopic CBD exploration has been described through the cystic duct or common duct using either fibreoptic instruments or radiologically guided wire baskets or balloons.78–81 The increased emphasis on improving techniques via the transcystic route is because of the ease of closure without the added need for intracorporeal suture technique, combined with postoperative recovery similar to cholecystectomy alone. Careful evaluation of the CBD diameter and stone load from the cholangiogram is required to determine the best approach.

The author’s preferred initial method of laparoscopic exploration is by fluoroscopic means using a C-arm image intensifier, which is mobile and provides dynamic images with angulation. We employ a 5.5-Fr 70-cm radio-opaque nylon catheter with soft tip and end hole along with a side arm that connects to a catheter for injection of contrast (Fig. 10.6). Once the cystic duct is opened for insertion of the cholangiogram catheter, absence of bile backflow is a signal to milk the cystic duct backwards to extrude stones caught in transit to the CBD, rather than push them onwards into the CBD. A cholangiogram is performed (Fig. 10.7a), note being taken of the cystic duct and bile duct diameter, number of stones, stone size and their distribution in the biliary tree. CBD stones that appear to be of a size suitable for removal via the cystic duct and are not too numerous indicate that transcystic clearance has a high chance of success. Transcystic clearance proceeds by passing a 75-cm-long stone extractor (Cook®, Wilson-Cook Medical GI Endoscopy Inc., North Carolina). The basket tip should be positioned well back from the cannula tip to avoid perforation of the duct. Once the cannula tip is progressed, under image intensification, the basket is advanced within the cannula to allow engagement of the stone, which is withdrawn into the basket and extracted via the cystic duct (Fig. 10.7b). It is useful to remove the proximal stones first, and vital to avoid opening the basket within the duodenum or withdrawing through the ampulla with the basket wires open. Any impacted stones can be dislodged by passing a 4-Fr Fogarty catheter beyond the stone and withdrawing the catheter with the balloon inflated. Failed disimpaction may require choledochoscopy and lithotripsy (Fig. 10.7c–f, Box 10.1).

Box 10.1 Techniques for improving transcystic clearance

• Careful dissection of cystic duct/CBD junction

• Avoidance of the spiral valves when incising cystic duct

• Careful examination of cholangiogram (‘did that stone pass through the cystic duct?’)

• Approach cystic duct from different or extra ports

• Choledochoscopy via cystic duct, with lithotripsy if required

• Vary retraction on fundus

Figure 10.6 Composite cholangiogram catheter and stone extraction basket used for laparoscopic transcystic exploration of the common bile duct. Reproduced with permission of Cook Australia.

Figure 10.7 (a) Cholangiogram of a 21-year-old jaundiced patient demonstrating multiple CBD stones with one impacted 3 cm proximal to ampulla. (b) Fluoroscopic view of bile duct showing after rapid transcystic four-wire basket retrieval of all except the impacted stone. (c) Transcystic choledochoscopic view of impacted stone, unable to be dislodged with a balloon catheter. (d) Transcystic ureteroscopic lithoclast stone fragmentation. (e) Wire basket stone retrieval under vision. (f) Fluoroscopic view of cleared bile duct.

Traditionally at open surgery, the common duct was decompressed postoperatively with a T-tube until it was known that the bile was draining satisfactorily through the ampulla and there was no bile leak. Most series of laparoscopic transcystic common duct explorations do not report the routine use of drainage of the common duct. A subhepatic drain is routine.

There is accumulating evidence, including three randomised trials, that 60–70% of patients are able to have their calculi cleared via the cystic duct.82–88

Laparoscopic choledochotomy

In up to 35% of patients, laparoscopic transcystic exploration of the CBD will fail to clear the CBD.82–88 Choledochotomy then needs to be considered. The only absolute contraindication to choledochotomy is a CBD diameter of less than 8 mm (Box 10.2). It should also be borne in mind that approximately one-third of stones detected at cholangiography may be passed spontaneously, and that exploration of a small duct may result in increased morbidity for the patient.⁸⁹ Therefore, laparoscopic choledochotomy is only an option for appropriately trained surgeons (Box 10.3).

Box 10.3 Useful tips in performing laparoscopic choledochotomy

• Deflate duodenum with nasogastric tube (NGT)

• Extra port to retract duodenum

• Leave cholangiocatheter in to prevent deflation

• Sharp scissors choledochotomy

• Intraoperative lithotripsy preferably by lithoclast

Once clearance of the duct has been confirmed by choledochoscopy (see below), a T-tube is inserted or primary closure can be considered with the insertion of an antegrade stent across the ampulla.⁸² Antegrade stenting, placement of a T-tube or cystic duct tube decompression of the CBD is wise where doubt exists about free postoperative bile drainage through the ampulla. This is most likely where a stone was impacted, ampullary manipulation has been extensive or in patients with established cholangitis. Placement of a subhepatic drain is essential.

Open choledochotomy

Successful exploration of the CBD can only be achieved through an adequately sized choledochotomy to facilitate both removal of any obvious stones and choledochoscopy. The gradual adoption of operative choledochoscopy during the 1970s and 1980s saw a decline in the incidence of retained CBD stones following surgery, from about 10% to 1.2%, with a number of surgeons reporting large series of patients with no retained stones.⁹⁰ On initial examination of the proximal ducts, it is normally possible to visualise several generations of ducts when these are dilated. Once it has been ascertained that the upper ducts are clear, the distal biliary tree can be examined. It is mandatory to clearly visualise the rather ragged appearance of the ampulla of Vater and then withdraw the choledochoscope. If a stone is visualised it can be retrieved with a stone basket and the procedure repeated until the duct is clear. The common duct is closed with or without a T-tube.⁹¹ The latter is probably unnecessary for an experienced choledochoscopist but, for the less experienced surgeon, it allows access to the biliary tree for postoperative cholangiography to confirm ductal clearance and to allow re-exploration of the duct without the need for re-operation.

Following the evolution of laparoscopic exploration of the bile duct, the most important area for laparotomy is for Mirizzi type 2–4 erosion of the bile duct by large stones and chronic inflammation. Reconstruction of the bile duct with the remaining gallbladder wall, or bilioenteric bypass in these circumstances, is best approached by laparotomy.

Endoscopic retrograde cholangiopancreatography (ERCP)

With the advent of laparoscopic cholecystectomy, ERCP and endoscopic sphincterotomy (ES) have become the usual procedure for treating common duct stones, since laparoscopic common duct exploration is not yet a widely practised technique (Box 10.4). Moreover, cholecystectomy without cholangiography is commonly performed in the expectation that ERCP and ES will be effective in dealing with unrecognised retained common duct stones at a later date. Such a policy, however, does expose the patient to an additional and often unnecessary procedure. Laparoscopic common duct exploration by whatever route has the advantage for the patient of being able to deal with both gallbladder and CBD stones at the same time.⁹²

Box 10.4 Reasons to consider converting to open choledochotomy

• Unsuccessful transcystic CBD exploration

• Unsuccessful laparoscopic choledochotomy

• Multiple (> 10) CBD stones

• Large CBD stones

• Intrahepatic or proximal ductal stones

• Impacted stones

• Failed or unavailable ERCP

There is general agreement that endoscopic removal of bile duct stones is preferable to surgery in postcholecystectomy patients, and in high-risk surgical patients when the gallbladder is still present – that is, patients with severe acute cholangitis and selected patients with acute biliary pancreatitis.93–95 The author believes ERCP becomes an option when transcystic CBD exploration has failed, but should not be considered the first-line management of all CBD stones.

Duct clearance can be expected in 90–95% of patients undergoing successful sphincterotomy, and this results in an overall success rate for endoscopic stone clearance of 80–95%, the highest success rates being recorded as experience increases.⁹³^,⁹⁵^,⁹⁶ Major complications occur in up to 10% of patients, and include haemorrhage, acute pancreatitis, cholangitis and retroduodenal perforation, but the overall procedure-related mortality is less than 1%.⁹³ However, the 30-day mortality can reach 15%, reflecting the severity of the underlying disease. In selected patients with calculi less than 15 mm in diameter, morbidity may be reduced by papillary dilatation rather than sphincterotomy.⁹⁴ Difficulties in removing CBD stones endoscopically may be due to unfavourable or abnormal anatomy, such as a periampullary diverticulum or previous surgery. Stones larger than 15 mm and those situated intrahepatically or proximal to a biliary stricture may be difficult to remove (Box 10.5). Adjuvant techniques include mechanical lithotripsy, extracorporeal shockwave lithotripsy and chemical dissolution.⁹⁵^,⁹⁷^,⁹⁸ Although successful stone fragmentation has been reported in up to 80% of patients, the major drawback is the need for multiple treatment sessions and at least one subsequent ERCP to extract stone fragments.

The establishment of ERCP in the prelaparoscopic era was based on the avoidance of an open exploration of the CBD, a procedure that was believed to have significant morbidity.⁹⁹ ERCP was therefore generally reserved for the high-risk surgical patients but open cholecystectomy and exploration of the CBD was reserved for the younger patient. In the laparoscopic era, management strategies vary considerably and are based on local endoscopic and laparoscopic resources and expertise.

ERCP stent insertion

In the 5% or less of situations where extraction of CBD stones is incomplete or impossible, a nasobiliary tube or stent should be inserted to provide biliary decompression and prevent stone impaction of the distal CBD (Fig. 10.8).¹⁰⁰ Such manoeuvres may allow improvement of the patient’s clinical condition until complete stone clearance can be achieved by further endoscopic manoeuvres or subsequent surgery. Temporary biliary endoprosthesis placement avoids accidental or intentional dislodgement of the nasobiliary catheter by a confused or uncooperative patient. The stent may become blocked after a few months, but bile drainage often continues around the stent, and the presence of the stent alone may be sufficient to prevent stones from becoming impacted at the lower end of the CBD. In the surgically unfit patient, a change of stent may be required if jaundice recurs. Recurrent episodes of cholangitis may result in secondary biliary cirrhosis in the long term, and careful consideration of the patient’s level of fitness must be made before surgery is totally discounted.

Figure 10.8 Multiple common bile duct stones lying above a mid-common bile duct stricture and not amenable to endoscopic extraction. Biliary drainage is maintained with two endoscopically placed stents.

Preoperative ERCP

For some, ERCP is the chosen method of preoperative CBD stone clearance, after imaging documentation of CBD stones with MRI or CT cholangiogram. The advantage of this strategy is that duct clearance preoperatively removes the dilemma as to how to manage CBD stones found at operation. ERCP as a tool to detect suspected stones without imaging exposes a substantial number of patients to an unnecessary endoscopic intervention.

A randomised study has shown no significant advantage for patients treated by preoperative sphincterotomy as opposed to open cholecystectomy and exploration of CBD alone.¹⁰¹ Despite this, ERCP and ES have become popular practice in the management of CBD stones, with an increased reliance on ERCP and a reluctance among surgeons to perform surgical exploration of the CBD.¹⁰²

Cholecystectomy should routinely follow clearance of the CBD except in those considered too frail or unfit for general anaesthetic. It can be expected that if the gallbladder is left intact following ERCP and ES, up to 47% of patients will develop at least one recurrent biliary event, with many requiring cholecystectomy.⁸⁶

Intraoperative ERCP

There have been several reports over the years describing this technique with success but few centres consider this the most appropriate use of resources.¹⁰³

Postoperative ERCP

If ductal stones are not suspected preoperatively, their presence can be determined at laparoscopic cholecystectomy by IOC. CBD stones identified in this way could be referred for postoperative endoscopic clearance if the surgeon was unable to explore the duct. Such a policy would reduce dramatically the number of ERCPs undertaken by a policy of routine or selective preoperative ERCP. This would leave only a small proportion of patients in whom stones could not be cleared by ERCP, requiring a second operation.¹⁰⁴ If the surgeon is trained in laparoscopic exploration of the CBD, ERCP should be reserved for the few patients in whom laparoscopic ductal clearance fails. A recent randomised trial lends some evidence that this approach is safe and represents an effective management plan.⁸⁸

At the present time, the precise role of ERCP remains to be defined but is likely to be dictated by local expertise and practice (see ‘Laparoscopic choledochotomy’ above). A number of acceptable algorithms have been proposed to manage laparoscopic cholecystectomy patients suspected of harbouring CBD stones.

There is also an argument for leaving small stones (< 5 mm) found intraoperatively. On follow-up for up to 33 months in a small group of patients, 29% in this category developed symptoms, but were safely managed with ERCP.¹⁰⁵

Laparoscopic exploration of the CBD versus preoperative or postoperative ERCP

At present, the array of management strategies for common duct stones requires data to guide us, with the techniques employed depending on local circumstances. In hospitals with ready access to ERCP, a surgeon may see little need for ascending the learning curve of laparoscopic CBD exploration, whereas those units with less ready access to ERCP see many attractions in dealing with common duct stones by laparoscopic means.

Preoperative ERCP and laparoscopic clearance of the CBD have been shown to be equivalent in overall outcomes.⁸³ However, those patients whose ductal stones were cleared transcystically experienced a far shorter hospital stay.

Postoperative ERCP clearance in a small single-surgeon study showed equivalent overall outcome to laparoscopic CBD clearance.⁸⁴ However, the number of choledochotomies was small and the retained stone rate high. Placement of biliary stents at the time of operation may improve the success of postoperative ERCP and stone clearance.

With experience, the majority of CBD stones can be treated at the time of surgery provided a flexible approach is employed.⁸⁵ No single technique will be applicable to the management of all stones. In general, if the stones are few in number, small (< 1 cm) in size, situated in the common duct or distal to cystic duct entry, then transcystic exploration has a high chance of success. If the stone or stones are large and numerous, or if the stones are situated in the common hepatic duct or intrahepatic biliary tree, a choledochotomy and exploration with the larger 5-mm choledochoscope is the preferred option.

Intraoperative stone fragmentation remains an option for stones found at operation that are unable to be dislodged at laparoscopic or open surgery, especially at the ampulla. This requires skills using the lithoclast for certain circumstances and laser or electrohydrolic fragmentation for others. Expertise in this area renders the transduodenal sphincteroplasty approach obsolete.

For those embarking on laparoscopic exploration, careful consideration of the strategies to be employed, equipment required and adequacy of assistance will go a long way to simplifying a potentially complex procedure. When laparoscopic transcystic exploration fails, the surgeon has three options:

• to ligate the cystic duct, complete the cholecystectomy and rely on postoperative ERCP;

• to perform a laparoscopic choledochotomy;

• to perform a laparotomy and open exploration of the CBD.

If laparoscopic choledochotomy fails, the options include: insertion of a T-tube and subsequent extraction of the retained stones via the T-tube track after 6 weeks; postoperative ERCP and sphincterotomy; or conversion to open exploration CBD. Individual circumstances will dictate which option is the most suitable, although this should be discussed carefully with the patient before a management strategy is implemented.

It has been suggested that preoperative ERCP is the most cost-effective management of patients at high risk for CBD stones.¹⁰⁶ There is evidence accumulating, however, that where transcystic clearance is successful this leads to less morbidity and more rapid recovery.⁸³^,⁸⁸ The author believes the most cost-effective approach is laparoscopic cholecystectomy, IOC and transcystic clearance of CBD stones, reserving ERCP for retained stones. Learning the techniques to achieve this seems worthwhile.

In a recent extensive review of the literature, it was concluded that laparoscopic CBD exploration is safe and effective for all patients presenting with gallstones and may be a better way of removing CBD stones than ERCP.¹⁰⁷^,¹⁰⁸

Recurrent or retained CBD stones

Recurrent CBD stones occur in up to 10% of cases. In a retrospective series of 169 patients followed for up to 19 years, recurrences were more common in patients with primary duct stones, large CBD diameter (around 16 mm) and periampullary diverticula. Lowest recurrence rates were found in those patients undergoing choledochoduodenostomy.⁷³

Retained CBD stones found at postoperative T-tube cholangiography are best dealt with by ERCP. If ERCP is unsuccessful or not available, exploration of the CBD via the T-tube tract is indicated. It usually takes approximately 6 weeks for the T-tube track to mature, at which time percutaneous choledochoscopy or radiologically guided extraction can be performed. A cholangiogram is obtained immediately prior to the procedure as a proportion of stones will have passed spontaneously.

The T-tube is removed, a guidewire is left in situ, and either a steerable catheter or choledochoscope is advanced down the track and into the CBD. With choledochoscopy, the remainder of the technique is identical to that carried out at open operation.¹⁰⁹ With the steerable catheter technique, fluoroscopy and further cholangiograms are taken as the stones are retrieved with a stone basket.¹¹⁰

If there is uncertainty as to the completeness of clearance, a straight tube may be inserted to keep the track open for a further attempt a few days later. Both techniques are successful in more than 95% of cases and carry less risk of complications such as pancreatitis or haemorrhage than ERCP. Providing there are no time constraints and the patient is happy to be managed as an outpatient with a T-tube, the technique is effective.

Transcystic exploration of the common bile duct at the time of cholecystectomy is an effective means of managing choledocholithiasis with low morbidity and cost.

ERCP is effective in managing the remaining patients in whom this is not achievable and is the accepted means of managing the patient presenting with acute cholangitis.

Transhepatic stone retrieval

In a few patients, particularly those who have previously undergone a Pólya gastrectomy, the ampulla will not be readily accessible for ERCP. Access to the common duct can be achieved using a percutaneous transhepatic technique. Over a percutaneously inserted guidewire, a series of dilators are advanced into the biliary tree, so as to develop a transhepatic tract. Following insertion of a sheath, a choledochoscope or steerable catheter can be inserted and stones retrieved.¹¹¹

Acalculous biliary pain

Given the poor understanding of the mechanisms of pain production in patients with acalculous biliary disease, the outcome for patients following cholecystectomy is uncertain. There is gathering evidence that some patients have abnormal motility of the sphincter of Oddi, in addition to the gallbladder. Some authors have reported improvement in symptoms in as many as 85–95% of patients with acalculous biliary pain after cholecystectomy,¹¹² but it is conceivable that surgery confers a placebo effect. Controversy exists over the use of cholecystokinin (CCK) provocation tests as a means of reproducing symptoms and predicting which patients might benefit from cholecystectomy. In one study, all 26 patients with positive CCK tests showed improvement after removal of the gallbladder,¹¹³ whereas 10 of the 16 patients with negative tests were found to have other pathology accounting for their pain. Despite these encouraging results, other investigators have failed to demonstrate differences in outcome in patients with positive CCK tests when compared to those with negative tests.¹¹⁴ Objective criteria on which to base the decision to recommend cholecystectomy in such patients are difficult to define. It is clear, however, that despite the minimally invasive nature of laparoscopic cholecystectomy, there should be no relaxation in the indications for cholecystectomy in patients with acalculous biliary pain.

Key points

• Asymptomatic gallstones do not require surgical intervention.

• The standard treatment for symptomatic gallstones is now laparoscopic, and there are few exceptions to a trial of a laparoscopic approach in all comers.

• All surgeons undertaking cholecystectomy, by whatever technique, should be capable of performing operative cholangiography.

• The use of operative cholangiography appears to be associated with a lower incidence of bile duct injury.

• Experience is accumulating that transcystic clearance of the CBD at the time of cholecystectomy is effective, with low morbidity and cost. In the one-third of patients where this is not achievable, ERCP is probably the best means of clearance.

• An algorithm for the management of common bile duct stones is shown in Fig. 10.9. The management strategy chosen will depend on personal experience, equipment availability, time and the availability of other departmental expertise. There is no consensus as to the ideal approach.