Updates in biliary endoscopy.
Introduction
This review addresses the literature in the field of biliary endoscopy for 2005. The topics are varied and range from newer techniques in the management of choledocholithiasis to the endoscopic management of benign and malignant biliary strictures. A series of studies were chosen using the Medline database and analyzed and reviewed to assist gastroenterologists and gastrointestinal surgeons in everyday practice.
Choledocholithiasis
Many techniques are available for the management of large bile duct stones. Electrohydraulic lithotripsy (EHL) is a technique gaining more critical analysis, particularly for difficult bile duct stones. Failure to remove large bile duct stones with standard extraction balloons or extraction baskets has been overcome by using mechanical lithotripsy with variable success rates that range from 68 to 100% depending upon stone size. The greatest success for mechanical lithotripsy is in stones of less than 3 cm and somewhat less so with stones of greater than 3 cm.
Benign and malignant biliary strictures
A relatively common complication of chronic pancreatitis is the formation of common bile duct strictures in up to 30% of patients. Indications for biliary drainage include obstructive jaundice, chronic abdominal pain, cholangitis, choledocholithiasis and persistent abnormalities in liver function tests, which may lead to secondary cirrhosis. Standard surgical approaches are associated with reasonably significant morbidity in this patient population. Alternative, less invasive approaches using endoscopic stenting have been explored. Short-term success is well known but long-term success remains in question. A recently published retrospective study evaluated the success of single stent placement and exchange every 3 months for up to 1 year in 62 patients, with a median follow-up of 45 months. Success of treatment was defined if there were no signs of recurrent stricture after permanent stent removal. In this study, long-term single-stent therapy resulted in resolution of the stricture in 38% of patients. Subgroup analysis indicated that the only factor predictive of successful resolution of the biliary stricture was concomitant acute pancreatitis.
A second, recently published study compared the long-term benefit of a single stent with that of multiple simultaneous stents for treatment of chronic pancreatitis-induced biliary strictures. A recent study using multiple simultaneously placed endobiliary stents in post-cholecystectomy-induced biliary strictures improved the success rate of stricture resolution. Given the poor response to single-stent therapy for chronic pancreatitis-induced biliary strictures, this more aggressive approach was applied in this study. In a prospective cohort, simultaneous stents (multiple stents) were placed in 12 patients and compared to a historical control population in whom single stents were placed (34 patients). All patients presented with symptoms related to biliary stenosis. The prospective population had 10 Fr stents placed in a simultaneous fashion every 3 months until four or five stents were in place over a mean of 14 months. The retrospective control cohort had a single 10 Fr stent placed and exchanged at 3–6 month intervals over a mean of 21 months. Patients were observed for complications, resolution of symptoms, correction of biochemical abnormalities and diameter of common bile duct stenosis.
A recent study has examined the use of expandable metallic biliary stents in resectable pancreatic cancer. The authors of this study reexamined the use of expandable metallic stents because the approach to the management of patients with pancreatic cancer has increased in complexity. In patients with resectable pancreatic cancer, a multidisciplinary approach is taken in many centers because recent data suggest that better outcomes may be achieved with preoperative chemoradiation. As biliary obstruction is common in this patient population, stent therapy is required prior to initiation of chemoradiation. Temporary plastic stents have generally been placed in patients thought to be resection candidates. Unfortunately, plastic stents have significantly shorter patency durations than self-expanding metallic stents. It is known that expandable metallic stents remain patent significantly longer than plastic stents and are more cost effective in patients with unresectable pancreatic cancer. It is also generally thought that expandable metallic stents interfere with pancreaticoduodenectomy and usually are not placed in resection candidates. As the duration in time increases from diagnosis to surgery, occlusion of biliary stents may become more common prior to surgery.
Management of postoperative bile leak
The previous largest study examining the approach to patients with post-cholecystectomy bile leaks was a multicenter trial that reviewed all patients referred for management of post-operative bile leaks to select centers in the early 1990s. A total of 50 patients underwent endoscopic therapy for the management of their bile leak which included endoscopic sphincterotomy, stent placement alone or endoscopic sphincterotomy with stent placement. No rationale was provided for method of endoscopic treatment. All leaks treated in this study healed at termination of this study. The outcome of this study suggested that endoscopic sphincterotomy, stent placement or sphincterotomy with stent placement were all effective in healing bile leaks after laparoscopic cholecystectomy but optimal endoscopic treatment was not defined.
A recently published study examined a total of 100 patients with suspected post-cholecystectomy bile leak, examining the outcomes in these patients. A cholangiogram was obtained in 96 patients. Eighty out of the 96 patients had a demonstrated bile leak. The most common site of the leak was the cystic duct stump followed by ducts of Luschka. All leaks treated with a stent alone (40) healed without the need for surgical correction and one patient required stent replacement and demonstrated healing soon afterwards. In the patients treated with endoscopic sphincterotomy alone (18), four required surgery to repair the leak, with an additional two requiring repeat ERCP with placement of a stent to complete the repair. Based on their results, the authors conclude that the optimal management for the treatment of a bile leak is ERCP with stent placement. An editorial review of this study concluded that a better analysis of the group of patients who required operative repair may provide predictors of failure, but not the optimal choice of endoscopic method, since only 18 patients underwent endoscopic sphincterotomy. The sample size was too small to draw any significant conclusions. Despite this weakness, this study supports the use of endoscopic biliary stent placement for the management of postoperative bile leaks with a high success rate of healing. This is supported by another similar study.
Techniques to improve success rate for biliary access
Probably the most frustrating and humbling experience for the biliary endoscopist is the inability to achieve selective cannulation of the bile duct. Even in the best of hands, cannulation of the appropriate duct may fail in 5–20% of cases. Fortunately, there are methods that have been developed to increase the likelihood of biliary access using a variety of pre-cut techniques with success rates of greater than 90%. The most common pre-cut technique is with the use of a needle-knife catheter. This involves making an incision with the needle knife through the sphincter into the bile duct. The disadvantage of this technique is the increased likelihood of complications. A newer technique recently described uses a standard sphincterotome after obtaining selective pancreatic cannulation.
Another study examined the use of a pancreatic duct stent to facilitate difficult bile duct cannulation. This retrospective study was performed to assess the efficacy and the complications of using pancreatic duct stents to guide difficult bile duct cannulations. A pancreatic duct stent was placed in 39 patients. Bile duct cannulation was achieved in 38 out of 39 patients (97%). Additionally, 23 patients required pre-cut sphincterotomy to facilitate cannulation. Two patients developed post-ERCP pancreatitis (5%). Twenty-three patients had failed outside attempts at bile duct cannulation. Placement of a pancreatic duct stent may facilitate biliary cannulation either as a guide for direct cannulation or in combination with pre-cut techniques with a low risk of complications.
Pancreatitis after endoscopic retrograde cholangiopancreatography
Pancreatitis remains the major complication from ERCP. Many studies have examined pharmacologic approaches to the prevention of post-ERCP pancreatitis but are not approved by the US Food and Drug Administration and may not be truly effective. A single study examining a pharmacologic approach to prevent post-ERCP pancreatitis was published in 2005. Ulinastatin is a protease inhibitor that ameliorates pancreatitis experimentally by inhibiting the chain reaction of pancreatic enzyme activation. A multicenter, randomized, double-blind, placebo-controlled trial in patients undergoing their first ERCP was performed in Japan. The primary end point for the study was post-ERCP pancreatitis with a secondary end point of hyperenzymemia. The study size was modest with 406 patients enrolled; 204 were in the ulinastatin arm and 202 in the placebo group. Hyperamylasemia and hyperlipasemia occurred in 24.8 and 37.6% of the placebo group and 14.7 and 25.5% of the ulinastatin group respectively.
Conclusion
This review focused on the advances in biliary endoscopy in the last year in the areas of the management of choledocholithiasis, benign and malignant biliary strictures and post-laparoscopic cholecystectomy-associated bile leaks, new techniques to improve biliary access by ERCP and assessment of their safety, and the pharmacologic prevention of ERCP-induced pancreatitis.
Summary:
This review addresses the literature in the field of biliary endoscopy for 2005. The topics are varied and range from newer techniques in the management of choledocholithiasis to the endoscopic management of benign and malignant biliary strictures. A series of studies were chosen using the Medline database and analyzed and reviewed to assist gastroenterologists and gastrointestinal surgeons in everyday practice.
Choledocholithiasis
Many techniques are available for the management of large bile duct stones. Electrohydraulic lithotripsy (EHL) is a technique gaining more critical analysis, particularly for difficult bile duct stones. Failure to remove large bile duct stones with standard extraction balloons or extraction baskets has been overcome by using mechanical lithotripsy with variable success rates that range from 68 to 100% depending upon stone size. The greatest success for mechanical lithotripsy is in stones of less than 3 cm and somewhat less so with stones of greater than 3 cm.
EHL using choledochoscope guidance has demonstrated promise for removal of large stones where other techniques, including mechanical lithotripsy, have failed. This technique employs the use of a bipolar electrode in an aqueous medium. The probe is placed at the surface of the stone and directly observed using a choledochoscope. The probe emits a series of spark discharges, creating a shock wave which fragments the stone. Stone fragments are then removed using conventional methods such as a balloon, basket or even mechanical lithotripsy. A retrospective review of 111 consecutive patients examined the use of EHL in patients who failed to have their stones removed using standard endoscopic retrograde cholangiopancreatography (ERCP)-directed methods. It was used in 94 of these patients with successful stone fragmentation achieved in one (76%), two (14%) and three or more sessions (10%), with 90% successful stone clearance. The disadvantage of this technique is the need to use a choledochoscope to guide the probe due to the possibility of damaging the bile duct, with fluoroscopic guidance being unreliable and possibly associated with increased complications. The other disadvantage is the need for two operators for the use of a choledochoscope.
A second study examining the use of EHL in a single-operator duodenoscope-assisted cholangioscope reported a 100% success rate for large bile duct stone removal after failure to remove using mechanical lithotripsy. This was a small study on 26 patients, only 12 of whom underwent mechanical lithotripsy prior to attempted EHL. Mechanical lithotripsy was not performed ahead of time when the patient had known intrahepatic stones, a known biliary stricture or impacted common bile duct stones. Although this study and others like it have been promising, the expertise in the use of EHL requires endoscopists that are also skilled in the use of a choledochoscope. Mechanical lithotripsy will likely continue to serve as the first-line approach to the management of large bile duct stones where conventional methods fail. EHL may be reserved for cases where mechanical lithotripsy fails or more specifically where stones are above a narrow duct segment, in the presence of impacted stones or where stones are lodged in the cystic duct.
Benign and malignant biliary strictures
A relatively common complication of chronic pancreatitis is the formation of common bile duct strictures in up to 30% of patients. Indications for biliary drainage include obstructive jaundice, chronic abdominal pain, cholangitis, choledocholithiasis and persistent abnormalities in liver function tests, which may lead to secondary cirrhosis. Standard surgical approaches are associated with reasonably significant morbidity in this patient population. Alternative, less invasive approaches using endoscopic stenting have been explored. Short-term success is well known but long-term success remains in question. A recently published retrospective study evaluated the success of single stent placement and exchange every 3 months for up to 1 year in 62 patients, with a median follow-up of 45 months. Success of treatment was defined if there were no signs of recurrent stricture after permanent stent removal. In this study, long-term single-stent therapy resulted in resolution of the stricture in 38% of patients. Subgroup analysis indicated that the only factor predictive of successful resolution of the biliary stricture was concomitant acute pancreatitis.
A second, recently published study compared the long-term benefit of a single stent with that of multiple simultaneous stents for treatment of chronic pancreatitis-induced biliary strictures. A recent study using multiple simultaneously placed endobiliary stents in post-cholecystectomy-induced biliary strictures improved the success rate of stricture resolution. Given the poor response to single-stent therapy for chronic pancreatitis-induced biliary strictures, this more aggressive approach was applied in this study. In a prospective cohort, simultaneous stents (multiple stents) were placed in 12 patients and compared to a historical control population in whom single stents were placed (34 patients). All patients presented with symptoms related to biliary stenosis. The prospective population had 10 Fr stents placed in a simultaneous fashion every 3 months until four or five stents were in place over a mean of 14 months. The retrospective control cohort had a single 10 Fr stent placed and exchanged at 3–6 month intervals over a mean of 21 months. Patients were observed for complications, resolution of symptoms, correction of biochemical abnormalities and diameter of common bile duct stenosis.
Mean follow-up was 3.9 years in the prospective cohort (multiple stents) and 4.2 years in the retrospective cohort (single stents). The results demonstrated that the multiple simultaneously placed stent option appears superior to the single-stent option with durable long-term benefit in 11 out of the 12 patients. The control population had six episodes of cholangitis (11%) occur in four patients. The prospective population had no patients develop cholangitis. In the control population, none of the 34 patients had durable benefit from single-stent therapy. This study supports the multiple simultaneously placed stent approach, which appears safe and possibly more effective than the single-stent approach, but larger studies are necessary.
A recent study has examined the use of expandable metallic biliary stents in resectable pancreatic cancer. The authors of this study reexamined the use of expandable metallic stents because the approach to the management of patients with pancreatic cancer has increased in complexity. In patients with resectable pancreatic cancer, a multidisciplinary approach is taken in many centers because recent data suggest that better outcomes may be achieved with preoperative chemoradiation. As biliary obstruction is common in this patient population, stent therapy is required prior to initiation of chemoradiation. Temporary plastic stents have generally been placed in patients thought to be resection candidates. Unfortunately, plastic stents have significantly shorter patency durations than self-expanding metallic stents. It is known that expandable metallic stents remain patent significantly longer than plastic stents and are more cost effective in patients with unresectable pancreatic cancer. It is also generally thought that expandable metallic stents interfere with pancreaticoduodenectomy and usually are not placed in resection candidates. As the duration in time increases from diagnosis to surgery, occlusion of biliary stents may become more common prior to surgery.
A recent study examined the number of patients who went to the operating room for possible pancreaticoduodenectomy with stents of either type in place. Thirteen patients had metallic stents and 42 patients had plastic endobiliary stents placed. Two out of the 13 patients (15%) required an additional ERCP after initial metallic stent placement for cholangitis before surgery, with an average of 106 days between last stent placement and surgery. Twelve out of the 13 patients with metallic stents went on to have pancreaticoduodenectomy. One out of 13 patients was not resectable due to the recognition of peritoneal metastases at exploration. In the plastic stent population, 16 out of 42 (38%) underwent at least three ERCP procedures prior to pancreaticoduodenectomy, with 39 out of 42 developing cholangitis or cholestasis at some point prior to surgery. In centers where preoperative chemoradiation therapy is protocol, placement of metallic stents in resectable pancreatic cancer should be considered and care should be taken to place the proximal end of the stent at least 2 cm below the hilum/bifurcation.
Management of postoperative bile leak
The previous largest study examining the approach to patients with post-cholecystectomy bile leaks was a multicenter trial that reviewed all patients referred for management of post-operative bile leaks to select centers in the early 1990s. A total of 50 patients underwent endoscopic therapy for the management of their bile leak which included endoscopic sphincterotomy, stent placement alone or endoscopic sphincterotomy with stent placement. No rationale was provided for method of endoscopic treatment. All leaks treated in this study healed at termination of this study. The outcome of this study suggested that endoscopic sphincterotomy, stent placement or sphincterotomy with stent placement were all effective in healing bile leaks after laparoscopic cholecystectomy but optimal endoscopic treatment was not defined.
A recently published study examined a total of 100 patients with suspected post-cholecystectomy bile leak, examining the outcomes in these patients. A cholangiogram was obtained in 96 patients. Eighty out of the 96 patients had a demonstrated bile leak. The most common site of the leak was the cystic duct stump followed by ducts of Luschka. All leaks treated with a stent alone (40) healed without the need for surgical correction and one patient required stent replacement and demonstrated healing soon afterwards. In the patients treated with endoscopic sphincterotomy alone (18), four required surgery to repair the leak, with an additional two requiring repeat ERCP with placement of a stent to complete the repair. Based on their results, the authors conclude that the optimal management for the treatment of a bile leak is ERCP with stent placement. An editorial review of this study concluded that a better analysis of the group of patients who required operative repair may provide predictors of failure, but not the optimal choice of endoscopic method, since only 18 patients underwent endoscopic sphincterotomy. The sample size was too small to draw any significant conclusions. Despite this weakness, this study supports the use of endoscopic biliary stent placement for the management of postoperative bile leaks with a high success rate of healing. This is supported by another similar study.
Techniques to improve success rate for biliary access
Probably the most frustrating and humbling experience for the biliary endoscopist is the inability to achieve selective cannulation of the bile duct. Even in the best of hands, cannulation of the appropriate duct may fail in 5–20% of cases. Fortunately, there are methods that have been developed to increase the likelihood of biliary access using a variety of pre-cut techniques with success rates of greater than 90%. The most common pre-cut technique is with the use of a needle-knife catheter. This involves making an incision with the needle knife through the sphincter into the bile duct. The disadvantage of this technique is the increased likelihood of complications. A newer technique recently described uses a standard sphincterotome after obtaining selective pancreatic cannulation.
A sphincterotomy is then directed toward the bile duct through the pancreaticobiliary septum to gain access to the biliary tree. Based on these preliminary data, a randomized trial was performed to compare the effectiveness and the complication rates of transpancreatic papillary septotomy versus needle-knife sphincterotomy for selective cannulation of the bile duct. The results of this study were impressive. The bile duct was cannulated in all 29 patients (100%) randomized to the transpancreatic septotomy sphincterotomy method, with complications in one patient (3.5%). Using pre-cut needle-knife sphincterotomy, the bile duct was cannulated in 26 out of 34 patients (77%), with complications occurring in six patients (17.7%). Although this pancreatic septotomy appears very promising, long-term complications such as pancreatic duct stenosis are of concern. Long-term follow-up of these patients is needed.
Another study examined the use of a pancreatic duct stent to facilitate difficult bile duct cannulation. This retrospective study was performed to assess the efficacy and the complications of using pancreatic duct stents to guide difficult bile duct cannulations. A pancreatic duct stent was placed in 39 patients. Bile duct cannulation was achieved in 38 out of 39 patients (97%). Additionally, 23 patients required pre-cut sphincterotomy to facilitate cannulation. Two patients developed post-ERCP pancreatitis (5%). Twenty-three patients had failed outside attempts at bile duct cannulation. Placement of a pancreatic duct stent may facilitate biliary cannulation either as a guide for direct cannulation or in combination with pre-cut techniques with a low risk of complications.
Pancreatitis after endoscopic retrograde cholangiopancreatography
Pancreatitis remains the major complication from ERCP. Many studies have examined pharmacologic approaches to the prevention of post-ERCP pancreatitis but are not approved by the US Food and Drug Administration and may not be truly effective. A single study examining a pharmacologic approach to prevent post-ERCP pancreatitis was published in 2005. Ulinastatin is a protease inhibitor that ameliorates pancreatitis experimentally by inhibiting the chain reaction of pancreatic enzyme activation. A multicenter, randomized, double-blind, placebo-controlled trial in patients undergoing their first ERCP was performed in Japan. The primary end point for the study was post-ERCP pancreatitis with a secondary end point of hyperenzymemia. The study size was modest with 406 patients enrolled; 204 were in the ulinastatin arm and 202 in the placebo group. Hyperamylasemia and hyperlipasemia occurred in 24.8 and 37.6% of the placebo group and 14.7 and 25.5% of the ulinastatin group respectively.
Pancreatitis occurred in 7.4% of the placebo group and 2.9% in the ulinastatin group. Despite the promising results in this and other trials, there are no guidelines for the use of these agents. Unfortunately most pharmacologic agents demonstrating promise for the prevention of post-ERCP pancreatitis in larger studies or meta-analyses have proven ineffective. This is the case with somatostatin and gabexate which are commonly used in Europe. The results seen in this study with ulinastatin are very promising. Further studies are necessary to validate these results.
Conclusion
This review focused on the advances in biliary endoscopy in the last year in the areas of the management of choledocholithiasis, benign and malignant biliary strictures and post-laparoscopic cholecystectomy-associated bile leaks, new techniques to improve biliary access by ERCP and assessment of their safety, and the pharmacologic prevention of ERCP-induced pancreatitis.
Summary:
This is an update of the work in the field of biliary endoscopy over the last year. The goal of this review is to address specific management concerns in the field of biliary endoscopy from the literature published in 2005.
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