BILIARY FISTULA ( Part two)

Bronchobiliary and Pleurobiliary Fistula
Bronchobiliary and pleurobiliary fistulas are fistulas between the biliary tree, often through the substance of the liver, and the pleural space or the bronchial tree.

• Most frequently they are associated with a subphrenic abscess with or without intrahepatic abscess.
• Echinococcal and amebic hepatic abscesses account for the majority of bronchobiliary or pleurobiliary fistulas.
• Other causes include biliary tract disease (usually obstructive), thoracoabdominal trauma, tuberculosis, syphilis, Hodgkin's disease, ascariasis, and, rarely, congenital communications.

The fistula forms by an abscess extending from within the liver substance coalescing with a right subphrenic abscess, which erodes through the posterior dome portion of the diaphragm.

• If the lung is adhering to the diaphragm because of inflammatory changes (80% of cases), a bronchobiliary fistula forms;
• if the lung does not adhere, a pleurobiliary fistula forms.

The chest radiograph is uniformly abnormal.

The studies most likely to reveal the course of the fistula, and possibly the cause,

• are direct cholangiograms:
• retrograde through an endoscope;
• percutaneous transhepatic;
• or fistulographic through an external biliary fistula, if present.
• Bronchoscopy infrequently establishes the bronchial site of the fistula and does little to demonstrate the responsible disorder.
• Bronchograms are not helpful in demonstrating a fistula or in establishing a cause.
  

Almost all patients with bronchobiliary fistula present with biloptysis, and about half of the patients present with acute dyspnea and bronchopneumonia.

• Three fourths of patients have chronic symptoms, with productive cough, recurrent pneumonia, and bronchiectasis of the lower lobe.
• Patients with pleurobiliary fistula usually present with sepsis.
• Fever, chills, jaundice, and abdominal pain are common presenting symptoms.
• An accompanying external biliary fistula is not infrequent.
  

Treatment follows three principles.

• The first is adequate treatment of intrahepatic and subphrenic abscesses.
• Pyogenic, amoebic, and echinococcal abscesses must be excised or drained as appropriate.
• The subphrenic abscess and any empyema must be well drained.
• The second principle is that any biliary obstruction must be alleviated.
• Operative biliary repair is not recommended until infection and the underlying cause are fully treated.
• Biliary decompression should be established with endoscopically or percutaneously placed stents until the conditions causing the biliary obstruction have resolved or until definitive repair can be approached in the absence of infection.
• The third principle is that the underlying cause must be treated.
  

Operative treatment of bronchobiliary and pleurobiliary fistulas may be complex, and, in the experience of some, it has required several operations in more than 60% of patients.

Biliary-Vascular Fistula
Biliary-vascular fistulas are rare communications between the bile ducts and blood vessels.

• The most commonly involved vessels are the hepatic arterial and portal venous branches within the liver; however, the hepatic veins, the main trunk of the hepatic artery, and the portal vein and other vessels may be involved.
• The most common cause of such connections is trauma,
• including iatrogenic trauma such as that incurred during needle liver biopsy,
• transhepatic drainage of the biliary tree, or
• transjugular intrahepatic portosystemic shunt placement.
• With penetrating trauma, direct communications may be established.
• With blunt trauma, direct communications are established less often; rather, injury to both vascular and biliary structures may occur; simultaneously, a large intrahepatic hematoma develops, and as the hematoma resolves the abnormal communication becomes manifest.
  
• A spontaneously occurring biliary-vascular fistula develops usually as a result of an abscess (pyogenic or parasitic) that erodes to form the biliary-vascular connection.
• Other causes are aneurysms of the hepatic arterial tree and intrahepatic tumor necrosis.
• Patients with these fistulas usually present with right upper quadrant pain, fluctuating jaundice, and mild to occasionally severe GI bleeding from hemobilia.
• Percutaneous or retrograde cholangiography may reveal filling defects in the biliary tree and gallbladder resulting from clot but only infrequently will demonstrate the fistula.

Treatment of fistulas associated with abscess may require operative drainage of the abscess and a difficult direct approach to the fistula.

• However, with the more common intrahepatic arteriobiliary communication, the blood vessel supplying the fistula is frequently amenable to angiographic embolization techniques.
• If the fistula is uncontrolled by angiographic embolization techniques, segmentectomy or lobectomy is generally safer than any attempt at direct approach to an intrahepatic fistula.
  

EXTERNAL BILIARY FISTULA
External biliary fistulas, or biliocutaneous fistulas, and internal bile leaks into the peritoneal cavity are aspects of the same process.

• Rarely, such fistulas occur spontaneously as a result of intrahepatic abscess (pyogenic or parasitic), necrosis and perforation of the gallbladder, or some other inflammatory process involving the biliary tree.
• Most external biliary fistulas and peritoneal bile leaks are postoperative complications of operations on the liver or biliary tree, with a few such fistulas resulting from trauma.
• With the advent of laparoscopic cholecystectomy, the associated increased incidence of bile duct injuries has made such fistulas or leaks more frequent.
• Specific causes of external biliary fistulas include
• leak from the cystic duct stump because of necrosis or inadequate ligation,
• undiscovered operative injury to the biliary ducts,
• prolonged cholecystostomy tube drainage,
• dislodgment of a T-tube from choledochotomy,
• persistent leakage of bile from a damaged liver or one in which a segment has been cut off from communication to the main bile ducts,
• continuing obstruction of the bile ducts by stone or stricture, cancer, or postoperative abscess around the liver.
  

These fistulas also occur after drainage of a hepatic abscess

• (particularly echinococcal),
• drainage of a biliary cyst,
• extensive loss of bile duct wall,
• or leakage from a biliary anastomosis,
• not uncommon after choledochocholedochostomy accompanying liver transplant.
  

Factors keeping such fistulas and leaks open include

• distal obstruction,
• ongoing inflammation,
• foreign body,
• cancer,
• the presence of ascites,
• and poor formation of fibrous connective tissue,
• such as in malnutrition or
• the use of steroids in transplant recipients.
  

Diagnostic studies should be aimed at delineation of the site of origin of the fistula in the biliary tree, the course of the fistula, and any factors operating to keep the fistula from healing.

• Fistulography with water-soluble contrast is often helpful, but when the fistula is indirect, such as through the cavity of an abscess, the internal anatomy is infrequently well demonstrated.
• ERC or percutaneous transhepatic cholangiography is usually necessary to delineate the site of the fistula and the presence of bile duct or intrahepatic stones or strictures that may be causing distal obstruction.
• When there is no communication between the biliary tree from which the fistula arises and the main bile ducts, a combination of fistula tract radiography and percutaneous and endoscopic cholangiography may be needed to delineate completely the anatomy and biliary site of injury and leak.
• Computed tomography or ultrasound should also be used to assess for associated subhepatic, subphrenic, or intrahepatic abscess.
  

Treatment principles for these fistulas consist of

• (1) removal of the inflammatory focus;
• (2) removal of any foreign body, such as bile duct stones or Ascaris lumbricoides; and
• (3) provision of unobstructed drainage of bile, into the intestine if feasible.

Drainage of any associated abscess or biloma is always the essential first step in cases of biliocutaneous fistula and internal bile leak.

• Usually, such drainage can be performed percutaneously under ultrasonographic or computed tomographic guidance.
• Frequently, for communicating fistulas with adequate abscess drainage when abscess is present, spontaneous fistula closure will occur as the abscess cavity closes.

In the past, removal of residual stones or other foreign bodies and provision of adequate bile drainage required an often arduous operative approach to the biliary tree near the site of the fistula, an operation made hazardous by scar and inflammatory tissue in the operative field.

The current approach to stones and other obstructing debris and to strictures is primarily endoscopic, by ERCP for diagnosis and endoscopic sphincterotomy for initial drainage and clearance of stones and debris.

• Many reports of endoscopic transsphincteric approaches to the biliary tree have documented remarkable success in the removal of stones and the provision of adequate drainage.
• Although some endoscopists have reported satisfactory closure of internal or external bile fistulas after endoscopic sphincterotomy alone, an endoscopically placed stent has allowed more consistent rapid closure of the biliocutaneous fistula by presumably more sufficient decompression of the biliary tree.
• An effective alternative for drainage is a nasobiliary tube placed within the leaking portion of the biliary tree and maintained on continuous suction.

When the endoscopic approach for drainage and clearance of stones is not possible, the percutaneous transhepatic approach can be used to provide drainage, although, by itself, the technique is not effective in clearing obstructing foreign material.

• However, at some centers, clearance of biliary debris can be accomplished through the percutaneously established tract, by using a small-diameter flexible scope and flushing and lithotripsy techniques.
• With such approaches, only a small percentage of patients with a communicating fistula will require operation, usually to alleviate obstruction and recurrent stones resulting from development of a stricture associated with the site of bile duct injury.

However, for patients with noncommunicating fistulas, although percutaneous drainage may often result in closure of the fistula by providing an alternate and low pressure route of egress of bile, the underlying lack of internal drainage of bile into the intestine is not solved and must be addressed.

• The anatomic situation leading to noncommunicating fistulas cannot usually be alleviated successfully by endoscopic or transhepatic interventional radiologic techniques alone.
• Percutaneous transhepatic radiologic techniques have been successful in re-establishing internal drainage by creating a tract between an isolated portion of the biliary tree and the intestine, and this re-established internal drainage has allowed the noncommunicating fistula to heal by its conversion to a communicating fistula.
• However, the established communication is not durable.
• Maintaining patency for what is essentially an internal biliary fistula requires a plastic or metal stent.
• Plastic stents require intermittent replacement because of progressive obstruction from buildup of bile salts, and metal expandable stents have not demonstrated prolonged patency when they are used in such an application.
• Central bile ducts with no established connection to the intestine, such as ligated or transected main or major hepatic bile duct branches, are best treated by Roux-en-Y biliary-enteric anastomosis to the appropriate bile duct, with a spatulated mucosa-to-mucosa anastomosis that is as large as possible.
• Concurrent excision of the fistula is feasible.

Noncommunicating biliary fistulas associated with small segmental or subsegmental bile ducts are usually initially best managed by adequate external drainage, usually percutaneously, with the drain placed as near as possible to the opening of the bile duct from the surface of the liver.

• Such placement is often directed at drainage of the biloma that has resulted from the transected or injured noncommunicating bile duct.
• These fistulas are seen most often after a non-anatomic liver resection, but they may occur from a duct of Luschka after cholecystectomy.
• The drain should be maintained on suction for at least 3 to 6 weeks and until any biloma resolves, documented by ultrasound or computed tomography, and until a fibrous tract has been established around the drain, documented by drain injection with water-soluble contrast showing only the drain and the isolated bile duct with no intraperitoneal extravasation.
• The drain can then be withdrawn 2 to 3 cm and maintained on suction.
• Unless the fistula is high volume, usually the fibrous tract will close down to close the fistula, and presumably the affected portion of liver atrophies.
• If the fistula persists, injection of the drain tract with a sclerosant such as hypertonic saline will often result in fistula closure.
• Such sclerosant treatment should be accompanied by appropriate antibiotic coverage.

Small-diameter noncommunicating segmental and subsegmental bile ducts have also been successfully managed with embolization to interrupt their drainage and presumably to initiate sclerosis and obliteration with atrophy of the drained portion of liver.