Bergman et al.⁴ described four types of postoperative bile duct injuries: Type A are cystic duct leaks or leakage from aberrant or peripheral hepatic radicles, type B are major bile duct leaks with or without concomitant biliary strictures, type C are bile duct strictures without bile leakage, and type D are complete transection of the duct with or without excision of some portion of the biliary tree.

Postoperative biliary strictures occur in 0.2% to 0.5% of patients and usually occur as a result of partial or complete transection by clipping or ligation of the bile duct, or less frequently as a result of vascular injury during dissection or cauterization. Injury to sectorial or segmental branches may occur in patients with anatomic anomalies of the biliary tree.

Approximately 10% to 30% of patients with advanced chronic pancreatitis develop symptomatic biliary stenosis.⁵ Biliary obstruction due to compression by an edematous pancreatic head or pseudocyst usually resolves when the inflammation subsides or after resolution of the pseudocyst. However, obstruction caused by a fibrotic stricture does not resolve spontaneously and requires therapeutic intervention.

Clinical Features

Approximately 10% of postoperative bile duct strictures present within 1 week of surgery. These usually occur as a result of inadvertent clipping or ligation of the common bile duct (CBD) and may or may not be associated with biliary leaks. Patients may present with abdominal pain, fever, pruritus, jaundice, or biliary fistula. However, in the majority of cases presentation is delayed and 70% to 80% present within 6 to 12 months of surgery.⁶ The presentation is symptomatic or asymptomatic cholestasis, recurrent cholangitis, stone formation, or secondary biliary cirrhosis.

Bismuth ⁷ classified benign strictures into five types: type I includes strictures with a common hepatic duct stump longer than 2 cm; type II includes strictures with a common hepatic duct stump shorter than 2 cm; type III lesions are those in which only the ceiling of the biliary confluence is intact; in type IV lesions the biliary confluence is interrupted; type V lesions are strictures of the hepatic duct associated with a stricture on a separate right branch. Bismuth types 1 and 2 strictures are the most frequent in reported series.⁸^–¹⁰

The clinical presentation of biliary strictures is somewhat different in patients with chronic pancreatitis.¹¹ In a retrospective survey of 78 patients with chronic pancreatitis, overt jaundice was found in only a minority of patients.¹² No relationship was found between features of the CBD and severity of pancreatitis or disease duration.

Diagnosis

The clinical diagnosis of postoperative biliary stricture is usually suspected by the onset of either symptomatic or biochemical cholestasis in the early or late postoperative period. In the first instance, ultrasound examination is performed to confirm biliary dilation and may suggest the level of biliary obstruction. Magnetic resonance cholangiopancreatography (MRCP) is a useful, noninvasive diagnostic modality for accurately delineating the biliary anatomy and site of stenosis and for planning definitive therapy.¹³ Strictures can also be found during endoscopic retrograde cholangiopancreatography (ERCP) performed mostly for removal of CBD stones and especially in postcholecystectomy patients.

Management

Traditionally, postoperative bile duct strictures were managed surgically and the role of ERCP was limited to the diagnosis and definition of the level and extent of the stricture.¹⁴ With the increasing use of ERCP for the treatment of acute adverse events of cholecystectomy, therapeutic ERCP has been extensively adopted to manage postoperative strictures and other benign biliary strictures. Percutaneous transhepatic therapy with balloon dilation of the stricture is limited by low success rates, high stricture recurrence rates, and high adverse event rates.^15,¹⁶ The high stricture recurrence rate following percutaneous transhepatic pneumatic dilation is most likely due to forceful disruption of the scar, which can add further traumatic damage to the tissue and consequent development of a new fibrotic reaction. Endoscopic treatment of a postoperative bile duct stricture is often preferred over percutaneous techniques because it avoids the need for liver puncture, and access to nondilated intrahepatic ducts is easier. Also, the endoscopic approach is more patient friendly and is safer in the presence of cirrhosis, ascites, or coagulopathy. Percutaneous transhepatic techniques are now usually reserved for failed endoscopic procedures or for rendezvous during endoscopy.

Endoscopic Technique

Endoscopic treatment of benign biliary strictures involves two technical steps: (1) negotiating the stricture and (2) dilation of the stricture.

Negotiating the Stricture

Negotiating the stricture requires continuity of the CBD. In cases of complete transection or ligation of the CBD, a guidewire cannot be passed across the lesion and thus endotherapy alone is not feasible. In such cases, surgical reconstruction is indicated, although a combined percutaneous endoscopic approach has been described.¹⁷

Negotiating benign biliary strictures is often much more difficult than neoplastic strictures because the stenosis, even if short, may be asymmetric. Furthermore, associated fibrosis makes them thin and tighter. It is therefore often necessary to use thin hydrophilic guidewires (0.021- or 0.018-in diameter) with a straight or curved (J-shaped) tip to get across. Guidewire manipulation requires patience, skill, and optimal fluoroscopic imaging. Forceful maneuvers may create false passages and should be avoided. Pulling an inflated stone retrieval balloon positioned just distal to the stricture results in stretching of the bile duct and modification of the axis of the guidewire. Steerable catheters or papillotomes may also be used to achieve the same result. Once the stricture is traversed, the hydrophilic guidewire is exchanged for a stiffer one to facilitate dilation. Sphincterotomy is usually performed due to the necessity for repeated stent exchanges and to allow for side-by-side placement of large-bore stents. When a stricture cannot be traversed at ERCP, a combined endoscopic percutaneous approach (rendezvous) can be used.

When placing self-expandable metal stents (SEMS) for benign biliary strictures, only one guidewire is placed across the stricture. SEMS delivery systems are usually 8.5 Fr in diameter and generally require stiffer, kink-resistant guidewires (e.g., Teflon-coated stiff wire or hydrophilic-coated nitinol wire).

Dilation of the Stricture

Stricture dilation has two objectives: (1) to reopen the CBD to achieve bile drainage and (2) to keep the stenosis open and avoid restricturing. Insertion of the guidewire through the stricture is followed by placement of a 6 Fr catheter over the guidewire and by mechanical dilation with a 9.5 Fr Cunningham-Cotton sleeve (Cook Medical, Winston-Salem, N.C.) to test the caliber of the stricture prior to attempting stent insertion. Hydrostatic balloon dilation with 4-, 6-, and 8-mm low-profile balloons (e.g., Hercules, Boston Scientific, Natick, Mass. or Titan, Cook Medical) may be necessary in cases where the stricture is not amenable to mechanical dilation. Balloon dilation is usually performed to a size 1 to 2 mm larger than the downstream bile duct diameter. Although immediately effective, endoscopic and percutaneous balloon dilation alone, whether in single or multiple sessions, is considered inadequate and associated with a high restenosis rate (up to 47%).^8,^18,¹⁹

Stent placement, on the other hand, keeps the stricture open for a prolonged period to allow scar remodeling and consolidation.²⁰ When mechanical or balloon dilation is unsuccessful, leaving a 5 or 6 Fr nasobiliary drainage tube in situ for 24 to 48 hours may increase the chances of subsequent endoscopic stent placement. Typically, 10 to 12 Fr polyethylene stents are placed and exchanged every 3 to 4 months to prevent cholangitis from stent occlusion. However, the optimal number of stents and duration of stent placement for stricture resolution has not been established.

SEMS have a larger luminal diameter (8 mm and 10 mm) and one stent is enough for treatment of benign biliary strictures of various etiologies. As for plastic stents, the duration of treatment for stricture resolution has not been established yet.

Only fully covered SEMS should be used because the high incidence of hyperplastic tissue reaction in the uncovered parts will often limit their removal.

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