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Management of Malignant Biliary Obstruction: Nonoperative and Palliative Techniques

Management of Malignant Biliary Obstruction: Nonoperative and Palliative Techniques

Introduction

Whereas surgery is still the gold standard for eradicating biliary
and other intestinal tumors, percutaneous transhepatic biliary
drainage, with or without placement of an endoprosthesis, has
become an integral part of the treatment of biliary obstruction
over the past 15 years[1,2]. Biliary drainage is a well-accepted
means of palliation for malignant biliary obstruction that has
been used both preoperatively and as the primary treatment in
patients whose disease is deemed unresectable [3].

Billiary Tract Drainage

Role in Treating Different Tumors

Biliary obstruction is caused by a wide range of tumors, and therefore,
therapy of the obstruction differs markedly, depending on the
lesion involved. Ampullary carcinoma is preferably treated surgically
with a Whipple procedure, and endoscopic biliary drainage is employed
only in exceptionally high-risk patients or those with metastatic
disease. In contrast, carcinoma of the pancreas is frequently
treated by biliary drainage, as the majority of patients with
this cancer present with advanced disease. In this situation,
the drainage is often performed endoscopically, since the primary
stricture is usually low-lying within the common bile duct.

High obstruction at the ductal confluence, which is beyond the
reach of most endoscopists, may be caused by cholangiocarcinoma,
gallbladder carcinoma, or adenopathy in the porta hepatis secondary
to a variety of metastases. Biliary drainage is often the primary
therapy for gallbladder carcinoma and adenopathy in the porta
hepatis, since, by the time gallbladder carcinoma causes biliary
obstruction, it is usually inoperative. Cholangiocarcinoma, when
resectable, may be treated operatively with a hepaticojejunostomy.
However, the majority of patients with a Klatzkin-type stricture
at the bile duct confluence have more extensive intrahepatic disease
at presentation that precludes curative surgical resection and/or
pose too great a surgical risk.

Postoperative patients may also develop jaundice secondary to
biliary obstruction. The concern in such patients is usually recurrent
malignancy; however, a stricture may simply represent a late-presenting
anastomotic stenosis. Benign anastomotic stenoses are well-treated
by biliary drainage combined with balloon dilatation, whereas
palliative drainage is the treatment of choice for recurrent disease
[4].

Indications

Jaundice alone is not an indication for percutaneous transhepatic
biliary drainage. The general indications for biliary tract drainage
are jaundice associated with cholangitis, sepsis, pruritus, and
nausea and vomiting leading to dehydration and malnutrition. In
patients with these symptoms, biliary drainage offers significant
palliation, and the benefits of the procedure outweigh the major
risks, which include bleeding, bacteremia and/or sepsis, hepatic
injury, and pneumothorax. Initial transhepatic cholangiography
is necessary to define the extent of an obstruction, particularly
with cholangiocarcinoma, and to plan for surgery.

Preoperative biliary drainage in patients who are jaundiced but
otherwise asymptomatic, especially those with carcinoma of the
pancreas, has not been found to be beneficial, but should be employed
in the rare patient presenting with acute ascending cholangitis.
Occasionally, the presence of a catheter in the extrahepatic bile
duct may assist the surgeon in creating a biliary bypass, in which
case preoperative endoscopic or transhepatic drainage may be considered.

Drainage Devices

Biliary drainage was first described in 1974 by Molnar and Stockum
[5] and was popularized in 1978 by Ring, who developed a suitable
catheter for internal drainage [3]. Initially, external drainage
was the treatment of choice, but it has the inconvenience of a
catheter with bile draining into a bag. Prolonged external drainage
of bile has the added disadvantage of electrolyte loss leading
to metabolic imbalance. Occasionally, however, it may be necessary,
particularly in patients who have high intra-abdominal or intraluminal
pressures within the duodenum and who have persistent leaks alongside
their catheter. Various techniques have been developed to readminister
this "lost" bile enterically, but these are often quite
difficult to tolerate.

Internal-External Catheters--As a result of these problems,
internal drainage with an internal-external catheter became the
standard therapy for nearly 10 years. These transhepatic catheters
are designed with side holes both above and below the level of
obstruction in the biliary tree; the tip of the catheter resides
within the bowel, so that bile drains through the catheter across
the obstruction and out of the side holes into the duodenum. Although
biliary obstructions are usually complete, it is almost always
possible for a trained interventional radiologist to negotiate
through a stricture with a combination of guidewires and catheters
under fluoroscopic guidance. With placement of an internally draining
catheter, nutrition is improved, and metabolic imbalance no longer
becomes an issue.

Most transhepatic biliary catheters are routinely changed every
2 months to avoid any chance of obstruction.
If such problems as deep pain, fever (> 101° F), or leakage
around the catheter onto the dressing develop, they can be managed
simply by exchanging the catheter for a new one. However, external-internal
catheters are a potential source of bacterial infection, are prone
to dislodgment and obstruction, and may be uncomfortable.

Furthermore, for many patients the external catheter is a constant
reminder of their cancer. Less frequently, it may be regarded
as a "lifeline," the device that saved the patient from
death. Therefore, maintenance of the catheter becomes the main
focus of the patient's life, and any problems that develop may
be perceived as a threat to his or her existence. Both of these
psychologically disruptive feelings encouraged the search for
a truly internal device.

Early Internal Devices--The first devices to achieve this
goal were a variety of endoprostheses, particularly the Carey-Coons
stent (12 French [4 mm] in diameter), which is used for distal
common bile duct strictures, such as that seen with carcinoma
of the pancreas; and the Miller stent, a double mushroom design
used for more proximal disease, as can be seen with cholangiocarcinoma.
These devices were designed to be implanted following an initial
trial of internal-external drainage. If internal drainage was
achieved satisfactorily by capping an internal-external catheter
(thereby forcing bile to flow into the duodenum), the internal-external
catheter could then be exchanged for an endoprosthesis that was
positioned over a guidewire, after which the percutaneous access
site was allowed to heal over.

Because nothing protrudes externally from the patient's side,
internal stents are generally tolerated much better by patients.
However, the expected patency of these synthetic catheters is
only on the order of 4 to 6 months. Radiologists originally used
Teflon for these catheters, but this material was found to have
a high rate of encrustation with sludge and bacteria, which are
the predominant sources of catheter obstruction.

Metallic Stents--In the late 1980s metallic stents came
into use (see Figure 1). These self-expanding stents may be introduced
through a sheath the same size as the initial biliary drainage
catheter. When deployed, they expand up to 10 mm (30 French) in
diameter [6].

In essence, the theoretical advantage of metallic stents is that
they provide a significantly larger lumen within the bile duct
without creating a large access hole within the liver. It was
believed that a much larger lumen would allow for a considerable
increase in patency. Furthermore, metal is not reactive in the
biliary tree, and progressively becomes incorporated into the
wall of the bile duct over several weeks' time.

In reality, however, patency remains a problem with stented malignant
biliary tract obstructions. Tumor ingrowth through the struts
of the stent and overgrowth over the ends of the stent have proved
to be major limitations of these newer devices. [7] The wider
struts of the zigzag Gianturco Z stent appear particularly susceptible
to tumor ingrowth. The woven mesh of the Wallstent design was
first reported by European researchers to be better, but it, too,
is susceptible to both tumor overgrowth and occasional ingrowth
[8].

To avoid tumor overgrowth and ingrowth, stenting over an extended
length of duct has been recommended. However, it does not totally
solve these problems. Silicone coating of the stents has been
proposed and tried in Europe, but no long-term data are available.
Inspissated bile may obstruct these stents, despite their relatively
large diameters.

Recent work suggests that the long-term patency of metal stents
alone in the treatment of malignant obstruction is little
more than 6 to 8 months [6-8]. However, in patients with carcinoma
of the pancreas or gallbladder, whose survival is generally limited,
this approach may provide sufficient palliation. Endoscopic stent
placement has become the primary approach for most patients with
carcinoma of the pancreas, since the obstruction tends to be low-lying
in the bile duct. Also, this approach avoids the potential problems
of hemobilia and pneumothorax associated with transhepatic drainage.
As a technique, endoscopic retrograde stent placement may be less
painful for the patient [2,3].

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