- Email: [email protected]
Plastic Pancreatic and Biliary Stents: Concepts and Insertion Techniques
SECTION 2
Chapter
16
TECHNIQUES
Plastic Pancreatic and Biliary Stents: Concepts and Insertion Techniques Todd H. Baron and Jeffrey L. Ponsky
INTRODUCTION AND SCIENTIFIC BASIS The use of plastic biliary stents for drainage of the bile duct was described over two decades ago1 and plastic stents are now used in the biliary tree for a variety of therapeutic indications.2 Applications in pancreatic disease have also developed.2 These stents are used for malignant and benign conditions and have proven reliable and safe in decompression of the biliary tree. Palliative insertion of biliary stents relieves distal biliary obstruction as effectively as surgical bypass.3 Plastic stents are available in a variety of configurations and lengths and are composed of Teflon, polyethylene, or polyurethane (Tables 16.1 and 16.2).2 Common configurations are straight, single pigtail, or double pigtail (Fig. 16.1A–16.1B). All plastic stents have limited patency due to occlusion with debris and biofilm (Fig. 16.2)4–6 and require periodic replacement when long-term drainage is required. Nearly all stents of the same diameter have similar patency rates. One 10Fr stent with a unique double layer design (Fig. 16.3) was shown in one study to have prolonged patency as compared to standard stent design.7 Plastic stents have been demonstrated to be easy to insert, effective for decompression, and inexpensive to use. Almost all plastic stents are hollow tubes. Side holes are present to a variable degree, but uniformly present in pancreatic duct stents to allow side branches to drain (Fig. 16.4). Recently, a star-shaped stent with a limited central lumen (Fig. 16.5) has become available for both biliary8 and pancreatic insertion (Viaduct, GI Supply®, Camp Hill, PA).9 The central lumen allows only a guidewire and is inserted without an inner guiding catheter even at 10 Fr diameter (see stent systems below). A new S-shaped pancreatic stent has been introduced which may have less potential for migration and a prolonged patency.10 Finally, a new biliary stent with an antireflux valve (wind-sock) has recently become available to prevent stent occlusion due to food and vegetable material (Cook Endoscopy, WinstonSalem, NC) (Fig. 16.6). This stent may have improved patency over conventional large bore 10 Fr stents.11
STENT SYSTEMS A variety of stent systems are available as discussed in Chapter 4. Stents of less than 8.5 Fr diameter are placed directly over a guidewire using a pusher tube or sphincterotome. Stents of greater than 8.5 Fr diameter typically come with an inner guiding catheter which passes over the guidewire (Fig. 16.7); the stent and pusher tube are then passed over the inner guiding catheter (Fig. 16.8). The inner guiding catheter promotes stability and rigidity which are necessary in passing through tight strictures.
Endoscope requirements For stents of 7 Fr in diameter a diagnostic channel endoscope can be used. However, nearly all modern duodenoscopes are equipped with a therapeutic channel (4.2 mm) which can accommodate stents up to 11.5 Fr in diameter.
Description of technique: biliary Because 10 Fr stents have a patency that is superior to 7 Fr stents, it is recommended that all patients with malignant disease who are undergoing plastic stent placement receive 10 Fr stents, if possible, so as to limit the number of endoscopic procedures required for long-term palliation.
Distal biliary obstruction The approach to distal biliary strictures is slightly more straightforward than for hilar tumors and will be discussed separately. After successful deep cannulation of the biliary tree contrast is introduced to clearly elucidate the margins of the stricture to allow the appropriate stent length to be chosen. The stricture is traversed with a guidewire. It is important to pass the wire well proximal to the stricture to prevent wire loss and to provide mechanical advantage. In general, a biliary sphincterotomy is not required for successful single 10 Fr stent insertion.12 If multiple stents are to be placed, however (for example in patients with benign disease in whom multiple stents are required), a biliary sphincterotomy is required. The guidewire is left in place. For placement of a single 10 Fr stent across a distal biliary stricture it is rarely necessary to dilate the stricture, since the mechanical advantage is great enough to overcome resistance. In cases of uncertainty, a 10 Fr dilating catheter (e.g. Soehendra dilator, Cook Endoscopy, Winston-Salem, NC) can be passed. If it traverses the stricture, then a 10 Fr stent will also traverse the stricture. Otherwise, hydrostatic balloon dilation can be performed. When the insertion of multiple stents is planned, stricture dilation is essential. In this setting, additional guidewires may be placed prior to placement of the first stent or may be passed alongside the first stent after its placement. When multiple stents are placed, it may be useful to place a slightly longer stent first as the friction of the second stent insertion may result in upward movement of the stent. If the first stent is too short it may disappear into the duct. This is usually of no consequence assuming that the stent is still across the stricture. The stent’s length should be selected based upon the distance from the papilla to the proximal edge of the stricture plus an additional 2 cm. Excessively long stents should be avoided as migration tends to occur until the proximal end of the stent impacts the top of the stricture; meanwhile, the distal end of the stent may then 153
SECTION 2 TECHNIQUES
MANUFACTURER/SHAPE ConMed ACS Size (F)a 5 6 7 8.5 10 11.5 12 Length (cm) 1 2.5 3 4 4.5 5 6 6.5 7 8 8.5 9 10 10.5 11 12 12.5 13 14 15 >15 Material Nylon Polyethylene Polyurethane Teflon Two layer Operator centered system Price Stent With delivery system With operator centered system
DP
Hobbs Medicalb ACS DP
√
√
√
√
√
√
√
√
√ √ √ √ √
√
√ √
Microvasive ACS DP
√
√
√
√
√
√
√ √
√
√ √
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√ √ √
√c
√
√ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √
√ √
No 60 115–130 N/A
No 40 86 N/A
Yes 69 119–159 139
DP
√
√
√ √
Olympus ACS
Yes 45–47 117–198 N/A
Cook Endoscopy ACS DP
√ √ √ √
√ √ √ √
√ √ √
√
√
√
√ √ √ √
√
√ √
√
√ √
√ √
√ √
√
√ √ √ √
√
√ √ Yes 57 123 123
Table 16.1 Plastic biliary stents (from reference no. 2 with permission) ACS, Angled, curved, or straight; DP, double pigtail. a Stents >10 Fr require a 4.2 mm channel duodenoscope. b Hobbs Medical did not disclose their stent material for this review. c Covered with hydromer coating.
impact the opposite duodenal wall causing perforation (Figs. 16.9A and 16.9B). As a rule of thumb, most pancreatic cancers producing biliary obstruction will be adequately managed with 5 or 7 cm long stents. Measuring of the stricture can be achieved in several ways. One way is during withdrawal of the initial cannulating catheter. When the catheter is at the proximal end of the stricture, the endoscopist holds the catheter just outside of the biopsy port; the catheter is then withdrawn until it is seen just outside of the papilla. The
154
distance from the endoscopist’s fingers to the biopsy port is measured, which is the minimal length of stent required to cross the lesion. Another way is to use the radiograph to “measure” the length from the top of the stricture to the tip of the endoscope when pressed against the papilla; the diameter of the endoscope serves as the comparison measuring point to account for the magnification factor. The following equation can be used to solve for the unknown (stricture length, Figure 16.10A–16.10B):
Chapter 16 Plastic Pancreatic and Biliary Stents: Concepts and Insertion Techniques
MANUFACTURER/SHAPE
Feature Size (F) 3 4 5 7 Length (cm) 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Material Price ($) (stent/preloaded)
GI Supply S
SP
Hobbs Medical S SP
√ √
√ √
√
√
√
√
√
√
√
√
√
√
√
√
Polyurethane 58
√ √
√
√
√
SP
Cook Endoscopy S SP √ 5, 7, 9
√ √
√ √
Olympus S
Not availablea 40
√ √ √ √ √ √ √
Polyethylene 49
√ 3–15 √
√ √ √ √ √ √ √ √ √ √ √ √ √
√ √ √ √ √ √ √ √ √ √ √ √ √
Polyethylene 57/123
Table 16.2 Pancreatic stents (from reference no. 2 with permission) S, Straight; SP, single pigtail. a Hobbs Medical did not disclose their stent material for this review.
A
B
Fig. 16.2 Endoscopic photo of occluded 10 Fr stent exiting the bile duct.
Fig. 16.1 Various stents: A Straight 10 Fr biliary stent (courtesy of Olympus America Inc., Melville, NY). B Double pigtail 10 Fr stent (courtesy of Cook Endoscopy, Winston-Salem, NC).
155
SECTION 2 TECHNIQUES
Fig. 16.3
Double-layer design (Olympus).
Fig. 16.7 Cook Endoscopy stent system showing typical 10 Fr design. Inner guiding catheter (arrows), stent (blue) and pusher tube (arrowheads) are seen.
Actual stricture length (X) Actual endoscope diameter = Measured stricture length Measured endoscope diameter
Fig. 16.4 Pancreatic duct stent, Cook Endoscopy. Note side holes.
Fig. 16.5 Magnified photograph of a sagittal section of a Viaduct stent. The flow is through the six channels (C) rather than through the central guidewire lumen (L).
Fig. 16.6 Antireflux stent (MarathonTM, Cook Endoscopy). The antireflux wind sock (white) is seen at the end of the stent. 156
Finally, fluoroscopic markers separated by a known distance are available on some catheters and guidewires and used as a reference point to the stricture and papilla. At this point, the stent is placed. The tapered end is the proximal end. Depending on the type of stent system, either the inner guiding catheter alone or the inner guiding catheter with the stent, are advanced over the guidewire. It is important not to allow the wire to pass too proximally into the biliary tree during this advancement, since this could cause hepatic capsule or intrahepatic ductal injury. On the other hand, excessive traction on the wire may result in wire loss. The stent is then advanced over the guide catheter by advancing the pusher tube, which is a somewhat larger bore and stiffer catheter which approximates the diameter of the stent. During advancement, the elevator should remain closed. When the stent impacts the elevator, the elevator is opened slightly to allow it to emerge from the endoscope channel. The elevator is closed to direct the stent upward and into the papilla. It is imperative to maintain a short endoscope position as close as possible to the papilla to maintain maximal mechanical advantage. Using a series of small movements in which the elevator is sequentially lowered to allow advancement of the stent, and then closed to advance the stent in a “ratchet-like” manner, the stent is advanced into the bile duct. Upward tip deflection as well as withdrawing the endoscope to further shorten it also provides forward motion to the stent. It is important to not allow more than a minimal amount of the stent to be advanced out of the endoscope into the duodenum; excessive length between the endoscope tip and papillary orifice decreases the mechanical advantage to forward advancement. To facilitate forward movement of the stent, the endoscopy assistant must provide traction on the inner guiding catheter. Once optimal stent position is achieved, the inner guiding catheter and guidewire are removed while the endoscopist maintains forward pressure with the pusher tube against the stent to prevent distal dislodgement. If additional contrast is needed to assess drainage or intrahepatic anatomy above the stent, the guidewire is removed prior to removing the inner guiding catheter to allow the injection. The guide catheter and pusher tube are then removed as described above. The process is repeated for additional stent placement.
Chapter 16 Plastic Pancreatic and Biliary Stents: Concepts and Insertion Techniques
Fig. 16.8 Illustration of 10 Fr stent system with stent placed for relief of malignant distal biliary obstruction.
A
B
the duct is then cannulated alongside the first stent with the second stent, guidewire, and inner guiding catheter. The process is continued until all stents are deployed. Alternatively, the stents can be placed one by one alongside each stent (Fig. 16.12). Newer stent delivery systems such as the Fusion (Cook Endoscopy) facilitate placement of multiple stents, since they allow intraductal exchange whereby the wire remains across the stricture between stent placements.
Stents for irretrievable bile duct stones Fig. 16.9 Endoscopic photos of distally migrated 11.5 Fr biliary stent impacted against the duodenal wall opposite the major papilla. A Before removal and B after removal, a small defect is seen.
In patients with short, distal bile strictures in whom multiple stents are to be placed (for example chronic pancreatitis with biliary stricture, post-sphincterotomy papillary stenosis) three to four 10 Fr 5 cm stents can be placed at one time on the inner guiding catheter. Once the first stent is in place (Fig. 16.11), the inner guiding catheter and guidewire are withdrawn just enough to release the first stent;
In the absence of a stricture, pigtail stents (Fig. 16.1b) may be preferable to straight stents when placed in a dilated biliary tree because they are less likely to migrate distally and completely out of the bile duct. Pigtail stents are placed slightly differently than straight stents in that if the distal end of the stent is against the papilla, too much stent has been advanced into the duct to allow the pigtail to form in the duodenum. The stent should be advanced until the portion of the stent that is just proximal to the distal pigtail (identified by applying indelible marker prior to placement if a visible marker is not already on the stent) is visible. The stent is then advanced while simultaneously withdrawing the endoscope so that the pigtail is deployed into the duodenum. 157
SECTION 2 TECHNIQUES
B A
Fig. 16.12 Additional stent insertion. Passage of the catheter alongside the initial stents in order to recannulate and place additional stents. Fig. 16.10 Measurement on the radiograph to calculate stent length. A The measurement from the top of the stricture to endoscope tip when positioned at the papilla (bracket) compared to the diameter of the endoscope (arrowheads) was 7 : 1. B Since the diameter of the endoscope was 11.5 mm, a 9 cm stent was placed.
A
B
be adequate to cross the stricture but too short to be “anchored” in the intrahepatic system are more prone to migrate distally. If it is determined that bilateral stents are to be placed, there are two options for guidewire placement. One way is the placement of two wires, one in each intrahepatic system, prior to placing either stent (Fig. 16.1). The other way is to place the first stent, recannulate the bile duct alongside this stent, and pass the guidewire into the opposite intrahepatic system. There are proponents of both methods, with advantages being the lack of friction within the endoscope channel between the first stent (if 10 Fr) and its larger pusher tube and the “second” guidewire within the endoscope channel. This can be overcome by using a 0.025″ guidewire as the “second wire.” It is important to note that it may not be possible to place bilateral 10 Fr stents during the first session. In that case it may be best to place two 7 Fr stents or one 10 Fr and one 7 Fr stent, then upsize one or both at the second session one month later.
Pancreatic duct stent insertion Fig. 16.11 Insertion of Multiple 10 Fr stents. A The first stent (1) is being pushed by the second stent (2) since the actual pusher tube is still well above the multiple stents loaded onto the catheter. B Final result of four 10 Fr stents, all placed with one passage of the stent introducer system.
Hilar biliary obstruction Hilar biliary obstruction differs from distal obstruction in two ways. Although a sphincterotomy is not needed for placement of a unilateral biliary stent, limited data suggest that hilar stent placement for obstruction carries a higher risk of pancreatitis than for distal obstruction, and pancreatitis, which may be prevented by performing a biliary sphincterotomy.13 Secondly, stricture dilation is frequently required because of the loss of mechanical advantage as the resistance of the stricture is away from the tip of the endoscope. Both of these maneuvers become mandatory when bilateral stents are placed (Fig. 16.13A–16.13C). In general, stents used for hilar tumors are 12–15 cm in length, since the average distance to the bifurcation is 9 cm. Stents that may 158
Pancreatic duct stent placement does not usually require the performance of a pancreatic sphincterotomy, especially since these stents have a small caliber (3–7 Fr). Rarely, 10 Fr stents are placed and even then a sphincterotomy for stent placement alone is usually unnecessary. The diameter of the stent chosen is dependent on the indication as well as the size of the main pancreatic duct. As mentioned previously, smaller diameter stents are passed over the guidewire without an inner guiding catheter. Similar to the biliary stenting process, the site of the pathology is identified, a wire passed into the tail and dilation performed, if necessary. The stent is selected and advanced into place with a pusher tube over the guidewire, although most 5, 6, or 7 Fr stents can be pushed into place using a standard 5 Fr catheter or sphincterotome. The wire is removed while keeping the pusher tube in position as mentioned. The pusher tube is then removed, leaving the end of the stent extruding from the papilla. Single pigtail stents with the pigtail in the duodenum are commonly employed in the pancreatic duct to avoid inward migration, which can be difficult to retrieve. Small caliber plastic stents (3–5 Fr) are now typically used for prevention of post-ERCP pancreatitis in patients at high risk (e.g. sphincter of Oddi dysfunction, ampullectomy) and/or the perfor-
Chapter 16 Plastic Pancreatic and Biliary Stents: Concepts and Insertion Techniques
A
B
C
Fig. 16.13 Bilateral stent placement for hilar cholangiocarcinoma. A Malignant stricture involves left (arrowhead) and right hepatic (arrow) ducts. B Balloon dilation is performed of left hepatic duct stricture (arrowhead); note wire is in right intrahe-patic (arrow). C Successful bilateral stent placement.
mance of high-risk interventions (precut biliary sphincterotomy, pancreatic sphincterotomy)14 (Fig. 16.14). These stents are expected to pass spontaneously within 14 days and thereby minimize pancreatic ductal injury.
Drainage of pancreatic fluid collections Double pigtail stents are placed transgastrically or transduodenally when transmural drainage of pancreatic fluid collections is undertaken.15 Usually two stents are placed across the wall into the collection (Fig. 16.15). Although straight stents can be used, they may be
a source of delayed bleeding as the end within the collection impacts the wall as the collection collapses.16 Therefore double pigtail stents are preferred. They are inserted as mentioned above for the biliary tree. It is important to note that the proximal ends of some of the 10 Fr stents are tapered and do not allow an inner guiding catheter to pass. The tapered portion may need to be severed to allow an inner guiding catheter pusher tube to pass through the stent. In addition, one must be especially careful that an excessive length of stent is not passed into a pseudocyst since the entire stent can be “lost” during deployment. 159
SECTION 2 TECHNIQUES
Fig. 16.14 3 Fr pancreatic duct stent placed for prevention of postERCP pancreatitis. Arrows denote ends of stent. Fig. 16.16 Plastic biliary stent (arrowhead) passed through occluded metal biliary stent (arrows) which had been placed for palliation of pancreatic carcinoma.
Fig. 16.15 Two 10 Fr stents placed transduodenally to drain a pancreatic pseudocyst.
Indications and contraindications Biliary indications Malignant biliary obstruction is the most frequent indication for the use of plastic stents. Distal obstruction is most commonly due to pancreatic carcinoma. Mid to proximal malignant obstruction may be due to primary cancer of the biliary tree (gallbladder or cholangiocarcinoma) or from invasion or obstruction of the duct by adjacent malignant metastatic lymph nodes. Plastic stents may be used to relieve obstruction of previously placed metal stents17 (Fig. 16.16). In general, distal bile duct tumors are more effectively palliated with plastic stents than are hilar tumors. Benign strictures can frequently be managed by the use of plastic stents. Causes of benign obstruction include post-sphincterotomy stenosis, chronic pancreatitis, post-surgical injury, ischemia, and anastomotic strictures after liver transplantation. Indeed, in addition to acute relief of obstruction, serial stenting and dilation with increasing numbers of stents appears to be more effective than single stents for such pathology18–20 (Fig. 16.17). Biliary leaks and fistulae after biliary surgery, cholecystectomy, or trauma are also effectively treated by short-term stent placement across the papilla21 (Fig. 16.18). In most of these latter indications short-length stents are effective and do not need to cross the leak site. The elimination of sphincter pres160
Fig. 16.17 Fluoroscopic image after placement of five stents for treatment of benign distal bile duct stricture.
sure promotes flow away from the leak into the duodenum, promoting closure. For more complex leaks and major leaks of the common bile duct, it may be necessary to traverse the leak site.
Pancreatic indications Plastic stents have been used for relief of pancreatic duct obstruction in the setting of chronic pancreatitis. In this setting there may refractory pain or pancreatic leaks, with resultant pancreatic ascites or pseudocysts.22 Occasionally malignant pancreatic duct obstruction will result in pancreatitis or contribute to disabling pain. Placement of pancreatic stents may be effective in this setting (Fig. 16.19).23 As previously mentioned, temporary stent placement is useful in the prevention of post-ERCP pancreatitis in selected patients. In the setting of severe acute pancreatitis, pancreatic duct leaks and disrup-
Chapter 16 Plastic Pancreatic and Biliary Stents: Concepts and Insertion Techniques
A B
C
Fig. 16.18 Placement of biliary stent for treatment of post-cholecystectomy cystic duct leak. A Active leak is seen. B Fluoroscopic image taken immediately after placement of 10 Fr biliary stent. C Follow-up cholangiogram several weeks later showing closure of leak.
Fig. 16.19 Placement plastic pancreatic stent in patient with unresectable pancreatic cancer, intractable pain, fever, and hyperamylasemia. A Stricture (arrowheads) and dilated main pancreatic duct (arrows). B Immediately after placement of stent. Significant improvement in pain was achieved.
B A
C
A B
Fig. 16.20 Placement of pancreatic stent for treatment of post-splenectomy pancreatic duct leak. A Active leak is seen. B Fluoroscopic image taken immediately after placement of 7 Fr pancreatic stent to tail. C Follow-up pancreatogram several weeks later showing closure of leak.
tions may contribute to the poor outcome of these patients; pancreatic stent placement may improve the clinical course in a subset of these patients.24 In patients with traumatic pancreatic ductal injury, plastic stents may be effective in bridging the injured duct and permitting resolution of the leak. Post surgical pancreatic duct
leaks (distal pancreatectomy, inadvertent surgical injury) can occur and are effectively treated with pancreatic stents (Fig. 16.20).25 Finally, a variety of plastic stent configurations have been useful in transpapillary and transmural drainage of pancreatic fluid collections (see Chapter 45).15 161
SECTION 2 TECHNIQUES
Complications When sphincterotomy is performed to facilitate stent insertion, complications such as hemorrhage (Fig. 16.21) or perforation may occur.26 When placed into the bile duct, problems caused by the stent itself include cholangitis, frequently due to stent occlusion, and cholecystitis as a result of cystic duct obstruction.27 Occlusion of a biliary stent secondary to deposition of bacterial biofilm and/or plant material (Fig. 16.2) is the most commonly encountered complication of plastic stents and occurs in about 30% of cases with resulting jaundice and cholangitis. When placed into the pancreatic duct, stent occlusion may cause pancreatitis. Stent migration, into or out of the bile duct, occurs in up to 5% of cases and may result in recurrent obstruction and cholangitis. Pancreatic stent migration into the duct can be difficult to retrieve due to their small diameter and the small size of the pancreatic duct. If not retrieved, permanent ductal damage can occur. Even when left in for a few weeks in a planned situation, pancreatic duct stents can induce ductal damage similar to chronic pancreatitis.28 (Figs 16.22A–16.22C). Uncommon complications include perforation of the duodenum if distal migration occurs (Fig. 16.9);29 such perforations may be occult until the stent is removed
Fig. 16.21 Endoscopically visible vessel (arrow) identified from post-sphincterotomy bleeding following biliary stent placement. Heater probe therapy was applied and no further bleeding ensued.
B A
C
Fig. 16.22 Pancreatic duct stent-induced ductal damage after treatment of post-tail resection pancreatic duct leak. A Active leak is seen at tail (arrow). B Fluoroscopic image taken immediately after placement of short 7 Fr pancreatic stent. C Follow-up pancreatogram several weeks later showing stricture (arrow) at site where the stent end was in contact with the duct.
and the hole opened. A variety of rare complications have been reported following migration completely out of the bile duct, such as bowel obstruction,30 and intestinal perforation.31
Relative cost Plastic stents provide rapid palliation of biliary obstruction, and shorten hospital stay when compared to surgical bypass. In many cases, stent placement obviates major surgical intervention. The cost of a plastic stent is less than $100 and is far less than an expandable
metal stent, the cost of which may exceed $1800 contingent upon manufacturer and presence or absence of a covering. Metal stents have a significantly longer patency than plastic stents, although if the patient does not survive long enough, this benefit will not be realized. Therefore, in patients with distal malignancy who have an anticipated life expectancy less than three to four months, plastic stents are more cost-effective.3,32 CPT codes and ambulatory payment classifications in the US for placement and/or removal of plastic biliary stents are available in a recent review.2
REFERENCES 1.
Soehendra N, Reynders-Frederix. Palliative bile duct drainage- a new endoscopic method of introducing a transpapillary drain. Endoscopy 1980; 12:8–11. 2. Somogyi L, Chuttani R, Croffie J, et al. Biliary and pancreatic stents. Gastrointest Endosc. 2006 June; 63(7):910–919. 3. Moss AC, Morris E, Mac Mathuna P. Palliative biliary stents for obstructing pancreatic carcinoma. Cochrane Database Syst Rev. 2006 Apr 19(2):CD004200. 162
4. van Berkel AM, van Marle J, Groen AK, et al. Mechanisms of biliary stent clogging: confocal laser scanning and scanning electron microscopy. Endoscopy. 2005 Aug; 37(8):729–734. 5. Farnbacher MJ, Voll RE, Faissner R, et al. Composition of clogging material in pancreatic endoprostheses. Gastrointest Endosc. 2005 June; 61(7):862–866. 6. Weickert U, Venzke T, Konig J, et al. Why do bilioduodenal plastic stents become occluded? A clinical and pathological investigation
Chapter 16 Plastic Pancreatic and Biliary Stents: Concepts and Insertion Techniques
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17. 18.
on 100 consecutive patients. Endoscopy. 2001 Sep; 33(9):786–790. Tringali A, Mutignani M, Perri V, et al. A prospective, randomized multicenter trial comparing DoubleLayer and polyethylene stents for malignant distal common bile duct strictures. Endoscopy. 2003 Dec; 35(12):992–997. Raju GS, Sud R, Elfert AA, et al. Biliary drainage by using stents without a central lumen: a pilot study. Gastrointest Endosc. 2006 Feb; 63(2):317–320. Raju GS, Gomez G, Xiao SY, et al. Effect of a novel pancreatic stent design on short-term pancreatic injury in a canine model. Endoscopy. 2006 Mar; 38(3):260–265. Ishihara T, Yamaguchi T, Seza K, et al. Efficacy of s-type stents for the treatment of the main pancreatic duct stricture in patients with chronic pancreatitis. Scand J Gastroenterol. 2006 June; 41(6):744–750. Reddy DN, Banerjee R, Choung OW. Antireflux biliary stents: are they the solution to stent occlusions? Curr Gastroenterol Rep. 2006 Apr; 8(2):156–160. Giorgio PD, Luca LD. Comparison of treatment outcomes between biliary plastic stent placements with and without endoscopic sphincterotomy for inoperable malignant common bile duct obstruction. World J Gastroenterol. 2004 Apr 15; 10(8):1212–1214. Tarnasky PR, Cunningham JT, Hawes RH, et al. Transpapillary stenting of proximal biliary strictures: does biliary sphincterotomy reduce the risk of postprocedure pancreatitis? Gastrointest Endosc. 1997 Jan; 45(1):46–51. Singh P, Das A, Isenberg G, et al. Does prophylactic pancreatic stent placement reduce the risk of post-ERCP acute pancreatitis? A meta-analysis of controlled trials. Gastrointest Endosc. 2004 Oct; 60(4):544–550. Baron TH. Endoscopic drainage of pancreatic fluid collections and pancreatic necrosis. Gastrointest Endosc Clin N Am. 2003 Oct; 13(4):743–764. Cahen D, Rauws E, Fockens P, et al. Endoscopic drainage of pancreatic pseudocysts: long-term outcome and procedural factors associated with safe and successful treatment. Endoscopy. 2005 Oct; 37(10):977–983. Tham TC, Carr-Locke DL, Vandervoort J, et al. Management of occluded biliary Wallstents.Gut. 1998 May; 42(5):703–707. Baron TH. Endoscopic therapy with multiple plastic stents for benign biliary strictures due to chronic calcific pancreatitis: the good, the bad, and the ugly. J Clin Gastroenterol. 2004 Feb; 38(2):96–98.
19. Pozsar J, Sahin P, Laszlo F, et al. Endoscopic treatment of sphincterotomy-associated distal common bile duct strictures by using sequential insertion of multiple plastic stents. Gastrointest Endosc. 2005 Jul; 62(1):85–91. 20. Kuzela L, Oltman M, Sutka J, et al. Prospective follow-up of patients with bile duct strictures secondary to laparoscopic cholecystectomy, treated endoscopically with multiple stents. Hepatogastroenterology. 2005 Sep–Oct; 52(65): 1357–1361. 21. Kaffes AJ, Hourigan L, De Luca N, et al. Impact of endoscopic intervention in 100 patients with suspected postcholecystectomy bile leak. Gastrointest Endosc. 2005 Feb; 61(2):269–275. 22. Delhaye M, Arvanitakis M, Bali M, et al. Endoscopic therapy for chronic pancreatitis. Scand J Surg. 2005; 94(2): 143–153. 23. Costamagna G, Mutignani M. Pancreatic stenting for malignant ductal obstruction. Dig Liver Dis. 2004 Sep; 36(9):635–638. 24. Lau ST, Simchuk EJ, Kozarek RA, et al. A pancreatic ductal leak should be sought to direct treatment in patients with acute pancreatitis. Am J Surg. 2001 May; 181(5):411–415. 25. Le Moine O, Matos C, Closset J, et al. Endoscopic management of pancreatic fistula after pancreatic and other abdominal surgery. Best Pract Res Clin Gastroenterol. 2004 Oct; 18(5):957–975. 26. Freeman ML, Nelson DB, Sherman S, et al. Complications of endoscopic biliary sphincterotomy. N Engl J Med. 1996 Sep 26; 335(13):909–918. 27. Dolan R, Pinkas H, Brady PG. Acute cholecystitis after palliative stenting for malignant obstruction of the biliary tree. Gastrointest Endosc. 1993 May–June; 39(3):447–449. 28. Kozarek RA. Pancreatic stents can induce ductal changes consistent with chronic pancreatitis. Gastrointest Endosc. 1990 Mar–Apr; 36(2):93–95. 29. Melita G, Curro G, Iapichino G, et al. Duodenal perforation secondary to biliary stent dislocation: a case report and review of the literature. Chir Ital. 2005 May–June; 57(3):385–388. 30. Simpson D, Cunningham C, Paterson-Brown S. Small bowel obstruction caused by a dislodged biliary stent. J R Coll Surg Edinb. 1998 June; 43(3):203. 31. Storkson RH, Edwin B, Reiertsen O, et al. Gut perforation caused by biliary endoprosthesis. Endoscopy. 2000 Jan; 32(1):87–89. 32. Levy MJ, Baron TH, Gostout CJ, et al. Palliation of malignant extrahepatic biliary obstruction with plastic versus expandable metal stents: An evidence-based approach. Clin Gastroenterol Hepatol. 2004 Apr; 2(4):273–285.
163
Chapter
16
TECHNIQUES
Plastic Pancreatic and Biliary Stents: Concepts and Insertion Techniques Todd H. Baron and Jeffrey L. Ponsky
INTRODUCTION AND SCIENTIFIC BASIS The use of plastic biliary stents for drainage of the bile duct was described over two decades ago1 and plastic stents are now used in the biliary tree for a variety of therapeutic indications.2 Applications in pancreatic disease have also developed.2 These stents are used for malignant and benign conditions and have proven reliable and safe in decompression of the biliary tree. Palliative insertion of biliary stents relieves distal biliary obstruction as effectively as surgical bypass.3 Plastic stents are available in a variety of configurations and lengths and are composed of Teflon, polyethylene, or polyurethane (Tables 16.1 and 16.2).2 Common configurations are straight, single pigtail, or double pigtail (Fig. 16.1A–16.1B). All plastic stents have limited patency due to occlusion with debris and biofilm (Fig. 16.2)4–6 and require periodic replacement when long-term drainage is required. Nearly all stents of the same diameter have similar patency rates. One 10Fr stent with a unique double layer design (Fig. 16.3) was shown in one study to have prolonged patency as compared to standard stent design.7 Plastic stents have been demonstrated to be easy to insert, effective for decompression, and inexpensive to use. Almost all plastic stents are hollow tubes. Side holes are present to a variable degree, but uniformly present in pancreatic duct stents to allow side branches to drain (Fig. 16.4). Recently, a star-shaped stent with a limited central lumen (Fig. 16.5) has become available for both biliary8 and pancreatic insertion (Viaduct, GI Supply®, Camp Hill, PA).9 The central lumen allows only a guidewire and is inserted without an inner guiding catheter even at 10 Fr diameter (see stent systems below). A new S-shaped pancreatic stent has been introduced which may have less potential for migration and a prolonged patency.10 Finally, a new biliary stent with an antireflux valve (wind-sock) has recently become available to prevent stent occlusion due to food and vegetable material (Cook Endoscopy, WinstonSalem, NC) (Fig. 16.6). This stent may have improved patency over conventional large bore 10 Fr stents.11
STENT SYSTEMS A variety of stent systems are available as discussed in Chapter 4. Stents of less than 8.5 Fr diameter are placed directly over a guidewire using a pusher tube or sphincterotome. Stents of greater than 8.5 Fr diameter typically come with an inner guiding catheter which passes over the guidewire (Fig. 16.7); the stent and pusher tube are then passed over the inner guiding catheter (Fig. 16.8). The inner guiding catheter promotes stability and rigidity which are necessary in passing through tight strictures.
Endoscope requirements For stents of 7 Fr in diameter a diagnostic channel endoscope can be used. However, nearly all modern duodenoscopes are equipped with a therapeutic channel (4.2 mm) which can accommodate stents up to 11.5 Fr in diameter.
Description of technique: biliary Because 10 Fr stents have a patency that is superior to 7 Fr stents, it is recommended that all patients with malignant disease who are undergoing plastic stent placement receive 10 Fr stents, if possible, so as to limit the number of endoscopic procedures required for long-term palliation.
Distal biliary obstruction The approach to distal biliary strictures is slightly more straightforward than for hilar tumors and will be discussed separately. After successful deep cannulation of the biliary tree contrast is introduced to clearly elucidate the margins of the stricture to allow the appropriate stent length to be chosen. The stricture is traversed with a guidewire. It is important to pass the wire well proximal to the stricture to prevent wire loss and to provide mechanical advantage. In general, a biliary sphincterotomy is not required for successful single 10 Fr stent insertion.12 If multiple stents are to be placed, however (for example in patients with benign disease in whom multiple stents are required), a biliary sphincterotomy is required. The guidewire is left in place. For placement of a single 10 Fr stent across a distal biliary stricture it is rarely necessary to dilate the stricture, since the mechanical advantage is great enough to overcome resistance. In cases of uncertainty, a 10 Fr dilating catheter (e.g. Soehendra dilator, Cook Endoscopy, Winston-Salem, NC) can be passed. If it traverses the stricture, then a 10 Fr stent will also traverse the stricture. Otherwise, hydrostatic balloon dilation can be performed. When the insertion of multiple stents is planned, stricture dilation is essential. In this setting, additional guidewires may be placed prior to placement of the first stent or may be passed alongside the first stent after its placement. When multiple stents are placed, it may be useful to place a slightly longer stent first as the friction of the second stent insertion may result in upward movement of the stent. If the first stent is too short it may disappear into the duct. This is usually of no consequence assuming that the stent is still across the stricture. The stent’s length should be selected based upon the distance from the papilla to the proximal edge of the stricture plus an additional 2 cm. Excessively long stents should be avoided as migration tends to occur until the proximal end of the stent impacts the top of the stricture; meanwhile, the distal end of the stent may then 153
SECTION 2 TECHNIQUES
MANUFACTURER/SHAPE ConMed ACS Size (F)a 5 6 7 8.5 10 11.5 12 Length (cm) 1 2.5 3 4 4.5 5 6 6.5 7 8 8.5 9 10 10.5 11 12 12.5 13 14 15 >15 Material Nylon Polyethylene Polyurethane Teflon Two layer Operator centered system Price Stent With delivery system With operator centered system
DP
Hobbs Medicalb ACS DP
√
√
√
√
√
√
√
√
√ √ √ √ √
√
√ √
Microvasive ACS DP
√
√
√
√
√
√
√ √
√
√ √
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√ √ √
√c
√
√ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √
√ √
No 60 115–130 N/A
No 40 86 N/A
Yes 69 119–159 139
DP
√
√
√ √
Olympus ACS
Yes 45–47 117–198 N/A
Cook Endoscopy ACS DP
√ √ √ √
√ √ √ √
√ √ √
√
√
√
√ √ √ √
√
√ √
√
√ √
√ √
√ √
√
√ √ √ √
√
√ √ Yes 57 123 123
Table 16.1 Plastic biliary stents (from reference no. 2 with permission) ACS, Angled, curved, or straight; DP, double pigtail. a Stents >10 Fr require a 4.2 mm channel duodenoscope. b Hobbs Medical did not disclose their stent material for this review. c Covered with hydromer coating.
impact the opposite duodenal wall causing perforation (Figs. 16.9A and 16.9B). As a rule of thumb, most pancreatic cancers producing biliary obstruction will be adequately managed with 5 or 7 cm long stents. Measuring of the stricture can be achieved in several ways. One way is during withdrawal of the initial cannulating catheter. When the catheter is at the proximal end of the stricture, the endoscopist holds the catheter just outside of the biopsy port; the catheter is then withdrawn until it is seen just outside of the papilla. The
154
distance from the endoscopist’s fingers to the biopsy port is measured, which is the minimal length of stent required to cross the lesion. Another way is to use the radiograph to “measure” the length from the top of the stricture to the tip of the endoscope when pressed against the papilla; the diameter of the endoscope serves as the comparison measuring point to account for the magnification factor. The following equation can be used to solve for the unknown (stricture length, Figure 16.10A–16.10B):
Chapter 16 Plastic Pancreatic and Biliary Stents: Concepts and Insertion Techniques
MANUFACTURER/SHAPE
Feature Size (F) 3 4 5 7 Length (cm) 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Material Price ($) (stent/preloaded)
GI Supply S
SP
Hobbs Medical S SP
√ √
√ √
√
√
√
√
√
√
√
√
√
√
√
√
Polyurethane 58
√ √
√
√
√
SP
Cook Endoscopy S SP √ 5, 7, 9
√ √
√ √
Olympus S
Not availablea 40
√ √ √ √ √ √ √
Polyethylene 49
√ 3–15 √
√ √ √ √ √ √ √ √ √ √ √ √ √
√ √ √ √ √ √ √ √ √ √ √ √ √
Polyethylene 57/123
Table 16.2 Pancreatic stents (from reference no. 2 with permission) S, Straight; SP, single pigtail. a Hobbs Medical did not disclose their stent material for this review.
A
B
Fig. 16.2 Endoscopic photo of occluded 10 Fr stent exiting the bile duct.
Fig. 16.1 Various stents: A Straight 10 Fr biliary stent (courtesy of Olympus America Inc., Melville, NY). B Double pigtail 10 Fr stent (courtesy of Cook Endoscopy, Winston-Salem, NC).
155
SECTION 2 TECHNIQUES
Fig. 16.3
Double-layer design (Olympus).
Fig. 16.7 Cook Endoscopy stent system showing typical 10 Fr design. Inner guiding catheter (arrows), stent (blue) and pusher tube (arrowheads) are seen.
Actual stricture length (X) Actual endoscope diameter = Measured stricture length Measured endoscope diameter
Fig. 16.4 Pancreatic duct stent, Cook Endoscopy. Note side holes.
Fig. 16.5 Magnified photograph of a sagittal section of a Viaduct stent. The flow is through the six channels (C) rather than through the central guidewire lumen (L).
Fig. 16.6 Antireflux stent (MarathonTM, Cook Endoscopy). The antireflux wind sock (white) is seen at the end of the stent. 156
Finally, fluoroscopic markers separated by a known distance are available on some catheters and guidewires and used as a reference point to the stricture and papilla. At this point, the stent is placed. The tapered end is the proximal end. Depending on the type of stent system, either the inner guiding catheter alone or the inner guiding catheter with the stent, are advanced over the guidewire. It is important not to allow the wire to pass too proximally into the biliary tree during this advancement, since this could cause hepatic capsule or intrahepatic ductal injury. On the other hand, excessive traction on the wire may result in wire loss. The stent is then advanced over the guide catheter by advancing the pusher tube, which is a somewhat larger bore and stiffer catheter which approximates the diameter of the stent. During advancement, the elevator should remain closed. When the stent impacts the elevator, the elevator is opened slightly to allow it to emerge from the endoscope channel. The elevator is closed to direct the stent upward and into the papilla. It is imperative to maintain a short endoscope position as close as possible to the papilla to maintain maximal mechanical advantage. Using a series of small movements in which the elevator is sequentially lowered to allow advancement of the stent, and then closed to advance the stent in a “ratchet-like” manner, the stent is advanced into the bile duct. Upward tip deflection as well as withdrawing the endoscope to further shorten it also provides forward motion to the stent. It is important to not allow more than a minimal amount of the stent to be advanced out of the endoscope into the duodenum; excessive length between the endoscope tip and papillary orifice decreases the mechanical advantage to forward advancement. To facilitate forward movement of the stent, the endoscopy assistant must provide traction on the inner guiding catheter. Once optimal stent position is achieved, the inner guiding catheter and guidewire are removed while the endoscopist maintains forward pressure with the pusher tube against the stent to prevent distal dislodgement. If additional contrast is needed to assess drainage or intrahepatic anatomy above the stent, the guidewire is removed prior to removing the inner guiding catheter to allow the injection. The guide catheter and pusher tube are then removed as described above. The process is repeated for additional stent placement.
Chapter 16 Plastic Pancreatic and Biliary Stents: Concepts and Insertion Techniques
Fig. 16.8 Illustration of 10 Fr stent system with stent placed for relief of malignant distal biliary obstruction.
A
B
the duct is then cannulated alongside the first stent with the second stent, guidewire, and inner guiding catheter. The process is continued until all stents are deployed. Alternatively, the stents can be placed one by one alongside each stent (Fig. 16.12). Newer stent delivery systems such as the Fusion (Cook Endoscopy) facilitate placement of multiple stents, since they allow intraductal exchange whereby the wire remains across the stricture between stent placements.
Stents for irretrievable bile duct stones Fig. 16.9 Endoscopic photos of distally migrated 11.5 Fr biliary stent impacted against the duodenal wall opposite the major papilla. A Before removal and B after removal, a small defect is seen.
In patients with short, distal bile strictures in whom multiple stents are to be placed (for example chronic pancreatitis with biliary stricture, post-sphincterotomy papillary stenosis) three to four 10 Fr 5 cm stents can be placed at one time on the inner guiding catheter. Once the first stent is in place (Fig. 16.11), the inner guiding catheter and guidewire are withdrawn just enough to release the first stent;
In the absence of a stricture, pigtail stents (Fig. 16.1b) may be preferable to straight stents when placed in a dilated biliary tree because they are less likely to migrate distally and completely out of the bile duct. Pigtail stents are placed slightly differently than straight stents in that if the distal end of the stent is against the papilla, too much stent has been advanced into the duct to allow the pigtail to form in the duodenum. The stent should be advanced until the portion of the stent that is just proximal to the distal pigtail (identified by applying indelible marker prior to placement if a visible marker is not already on the stent) is visible. The stent is then advanced while simultaneously withdrawing the endoscope so that the pigtail is deployed into the duodenum. 157
SECTION 2 TECHNIQUES
B A
Fig. 16.12 Additional stent insertion. Passage of the catheter alongside the initial stents in order to recannulate and place additional stents. Fig. 16.10 Measurement on the radiograph to calculate stent length. A The measurement from the top of the stricture to endoscope tip when positioned at the papilla (bracket) compared to the diameter of the endoscope (arrowheads) was 7 : 1. B Since the diameter of the endoscope was 11.5 mm, a 9 cm stent was placed.
A
B
be adequate to cross the stricture but too short to be “anchored” in the intrahepatic system are more prone to migrate distally. If it is determined that bilateral stents are to be placed, there are two options for guidewire placement. One way is the placement of two wires, one in each intrahepatic system, prior to placing either stent (Fig. 16.1). The other way is to place the first stent, recannulate the bile duct alongside this stent, and pass the guidewire into the opposite intrahepatic system. There are proponents of both methods, with advantages being the lack of friction within the endoscope channel between the first stent (if 10 Fr) and its larger pusher tube and the “second” guidewire within the endoscope channel. This can be overcome by using a 0.025″ guidewire as the “second wire.” It is important to note that it may not be possible to place bilateral 10 Fr stents during the first session. In that case it may be best to place two 7 Fr stents or one 10 Fr and one 7 Fr stent, then upsize one or both at the second session one month later.
Pancreatic duct stent insertion Fig. 16.11 Insertion of Multiple 10 Fr stents. A The first stent (1) is being pushed by the second stent (2) since the actual pusher tube is still well above the multiple stents loaded onto the catheter. B Final result of four 10 Fr stents, all placed with one passage of the stent introducer system.
Hilar biliary obstruction Hilar biliary obstruction differs from distal obstruction in two ways. Although a sphincterotomy is not needed for placement of a unilateral biliary stent, limited data suggest that hilar stent placement for obstruction carries a higher risk of pancreatitis than for distal obstruction, and pancreatitis, which may be prevented by performing a biliary sphincterotomy.13 Secondly, stricture dilation is frequently required because of the loss of mechanical advantage as the resistance of the stricture is away from the tip of the endoscope. Both of these maneuvers become mandatory when bilateral stents are placed (Fig. 16.13A–16.13C). In general, stents used for hilar tumors are 12–15 cm in length, since the average distance to the bifurcation is 9 cm. Stents that may 158
Pancreatic duct stent placement does not usually require the performance of a pancreatic sphincterotomy, especially since these stents have a small caliber (3–7 Fr). Rarely, 10 Fr stents are placed and even then a sphincterotomy for stent placement alone is usually unnecessary. The diameter of the stent chosen is dependent on the indication as well as the size of the main pancreatic duct. As mentioned previously, smaller diameter stents are passed over the guidewire without an inner guiding catheter. Similar to the biliary stenting process, the site of the pathology is identified, a wire passed into the tail and dilation performed, if necessary. The stent is selected and advanced into place with a pusher tube over the guidewire, although most 5, 6, or 7 Fr stents can be pushed into place using a standard 5 Fr catheter or sphincterotome. The wire is removed while keeping the pusher tube in position as mentioned. The pusher tube is then removed, leaving the end of the stent extruding from the papilla. Single pigtail stents with the pigtail in the duodenum are commonly employed in the pancreatic duct to avoid inward migration, which can be difficult to retrieve. Small caliber plastic stents (3–5 Fr) are now typically used for prevention of post-ERCP pancreatitis in patients at high risk (e.g. sphincter of Oddi dysfunction, ampullectomy) and/or the perfor-
Chapter 16 Plastic Pancreatic and Biliary Stents: Concepts and Insertion Techniques
A
B
C
Fig. 16.13 Bilateral stent placement for hilar cholangiocarcinoma. A Malignant stricture involves left (arrowhead) and right hepatic (arrow) ducts. B Balloon dilation is performed of left hepatic duct stricture (arrowhead); note wire is in right intrahe-patic (arrow). C Successful bilateral stent placement.
mance of high-risk interventions (precut biliary sphincterotomy, pancreatic sphincterotomy)14 (Fig. 16.14). These stents are expected to pass spontaneously within 14 days and thereby minimize pancreatic ductal injury.
Drainage of pancreatic fluid collections Double pigtail stents are placed transgastrically or transduodenally when transmural drainage of pancreatic fluid collections is undertaken.15 Usually two stents are placed across the wall into the collection (Fig. 16.15). Although straight stents can be used, they may be
a source of delayed bleeding as the end within the collection impacts the wall as the collection collapses.16 Therefore double pigtail stents are preferred. They are inserted as mentioned above for the biliary tree. It is important to note that the proximal ends of some of the 10 Fr stents are tapered and do not allow an inner guiding catheter to pass. The tapered portion may need to be severed to allow an inner guiding catheter pusher tube to pass through the stent. In addition, one must be especially careful that an excessive length of stent is not passed into a pseudocyst since the entire stent can be “lost” during deployment. 159
SECTION 2 TECHNIQUES
Fig. 16.14 3 Fr pancreatic duct stent placed for prevention of postERCP pancreatitis. Arrows denote ends of stent. Fig. 16.16 Plastic biliary stent (arrowhead) passed through occluded metal biliary stent (arrows) which had been placed for palliation of pancreatic carcinoma.
Fig. 16.15 Two 10 Fr stents placed transduodenally to drain a pancreatic pseudocyst.
Indications and contraindications Biliary indications Malignant biliary obstruction is the most frequent indication for the use of plastic stents. Distal obstruction is most commonly due to pancreatic carcinoma. Mid to proximal malignant obstruction may be due to primary cancer of the biliary tree (gallbladder or cholangiocarcinoma) or from invasion or obstruction of the duct by adjacent malignant metastatic lymph nodes. Plastic stents may be used to relieve obstruction of previously placed metal stents17 (Fig. 16.16). In general, distal bile duct tumors are more effectively palliated with plastic stents than are hilar tumors. Benign strictures can frequently be managed by the use of plastic stents. Causes of benign obstruction include post-sphincterotomy stenosis, chronic pancreatitis, post-surgical injury, ischemia, and anastomotic strictures after liver transplantation. Indeed, in addition to acute relief of obstruction, serial stenting and dilation with increasing numbers of stents appears to be more effective than single stents for such pathology18–20 (Fig. 16.17). Biliary leaks and fistulae after biliary surgery, cholecystectomy, or trauma are also effectively treated by short-term stent placement across the papilla21 (Fig. 16.18). In most of these latter indications short-length stents are effective and do not need to cross the leak site. The elimination of sphincter pres160
Fig. 16.17 Fluoroscopic image after placement of five stents for treatment of benign distal bile duct stricture.
sure promotes flow away from the leak into the duodenum, promoting closure. For more complex leaks and major leaks of the common bile duct, it may be necessary to traverse the leak site.
Pancreatic indications Plastic stents have been used for relief of pancreatic duct obstruction in the setting of chronic pancreatitis. In this setting there may refractory pain or pancreatic leaks, with resultant pancreatic ascites or pseudocysts.22 Occasionally malignant pancreatic duct obstruction will result in pancreatitis or contribute to disabling pain. Placement of pancreatic stents may be effective in this setting (Fig. 16.19).23 As previously mentioned, temporary stent placement is useful in the prevention of post-ERCP pancreatitis in selected patients. In the setting of severe acute pancreatitis, pancreatic duct leaks and disrup-
Chapter 16 Plastic Pancreatic and Biliary Stents: Concepts and Insertion Techniques
A B
C
Fig. 16.18 Placement of biliary stent for treatment of post-cholecystectomy cystic duct leak. A Active leak is seen. B Fluoroscopic image taken immediately after placement of 10 Fr biliary stent. C Follow-up cholangiogram several weeks later showing closure of leak.
Fig. 16.19 Placement plastic pancreatic stent in patient with unresectable pancreatic cancer, intractable pain, fever, and hyperamylasemia. A Stricture (arrowheads) and dilated main pancreatic duct (arrows). B Immediately after placement of stent. Significant improvement in pain was achieved.
B A
C
A B
Fig. 16.20 Placement of pancreatic stent for treatment of post-splenectomy pancreatic duct leak. A Active leak is seen. B Fluoroscopic image taken immediately after placement of 7 Fr pancreatic stent to tail. C Follow-up pancreatogram several weeks later showing closure of leak.
tions may contribute to the poor outcome of these patients; pancreatic stent placement may improve the clinical course in a subset of these patients.24 In patients with traumatic pancreatic ductal injury, plastic stents may be effective in bridging the injured duct and permitting resolution of the leak. Post surgical pancreatic duct
leaks (distal pancreatectomy, inadvertent surgical injury) can occur and are effectively treated with pancreatic stents (Fig. 16.20).25 Finally, a variety of plastic stent configurations have been useful in transpapillary and transmural drainage of pancreatic fluid collections (see Chapter 45).15 161
SECTION 2 TECHNIQUES
Complications When sphincterotomy is performed to facilitate stent insertion, complications such as hemorrhage (Fig. 16.21) or perforation may occur.26 When placed into the bile duct, problems caused by the stent itself include cholangitis, frequently due to stent occlusion, and cholecystitis as a result of cystic duct obstruction.27 Occlusion of a biliary stent secondary to deposition of bacterial biofilm and/or plant material (Fig. 16.2) is the most commonly encountered complication of plastic stents and occurs in about 30% of cases with resulting jaundice and cholangitis. When placed into the pancreatic duct, stent occlusion may cause pancreatitis. Stent migration, into or out of the bile duct, occurs in up to 5% of cases and may result in recurrent obstruction and cholangitis. Pancreatic stent migration into the duct can be difficult to retrieve due to their small diameter and the small size of the pancreatic duct. If not retrieved, permanent ductal damage can occur. Even when left in for a few weeks in a planned situation, pancreatic duct stents can induce ductal damage similar to chronic pancreatitis.28 (Figs 16.22A–16.22C). Uncommon complications include perforation of the duodenum if distal migration occurs (Fig. 16.9);29 such perforations may be occult until the stent is removed
Fig. 16.21 Endoscopically visible vessel (arrow) identified from post-sphincterotomy bleeding following biliary stent placement. Heater probe therapy was applied and no further bleeding ensued.
B A
C
Fig. 16.22 Pancreatic duct stent-induced ductal damage after treatment of post-tail resection pancreatic duct leak. A Active leak is seen at tail (arrow). B Fluoroscopic image taken immediately after placement of short 7 Fr pancreatic stent. C Follow-up pancreatogram several weeks later showing stricture (arrow) at site where the stent end was in contact with the duct.
and the hole opened. A variety of rare complications have been reported following migration completely out of the bile duct, such as bowel obstruction,30 and intestinal perforation.31
Relative cost Plastic stents provide rapid palliation of biliary obstruction, and shorten hospital stay when compared to surgical bypass. In many cases, stent placement obviates major surgical intervention. The cost of a plastic stent is less than $100 and is far less than an expandable
metal stent, the cost of which may exceed $1800 contingent upon manufacturer and presence or absence of a covering. Metal stents have a significantly longer patency than plastic stents, although if the patient does not survive long enough, this benefit will not be realized. Therefore, in patients with distal malignancy who have an anticipated life expectancy less than three to four months, plastic stents are more cost-effective.3,32 CPT codes and ambulatory payment classifications in the US for placement and/or removal of plastic biliary stents are available in a recent review.2
REFERENCES 1.
Soehendra N, Reynders-Frederix. Palliative bile duct drainage- a new endoscopic method of introducing a transpapillary drain. Endoscopy 1980; 12:8–11. 2. Somogyi L, Chuttani R, Croffie J, et al. Biliary and pancreatic stents. Gastrointest Endosc. 2006 June; 63(7):910–919. 3. Moss AC, Morris E, Mac Mathuna P. Palliative biliary stents for obstructing pancreatic carcinoma. Cochrane Database Syst Rev. 2006 Apr 19(2):CD004200. 162
4. van Berkel AM, van Marle J, Groen AK, et al. Mechanisms of biliary stent clogging: confocal laser scanning and scanning electron microscopy. Endoscopy. 2005 Aug; 37(8):729–734. 5. Farnbacher MJ, Voll RE, Faissner R, et al. Composition of clogging material in pancreatic endoprostheses. Gastrointest Endosc. 2005 June; 61(7):862–866. 6. Weickert U, Venzke T, Konig J, et al. Why do bilioduodenal plastic stents become occluded? A clinical and pathological investigation
Chapter 16 Plastic Pancreatic and Biliary Stents: Concepts and Insertion Techniques
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17. 18.
on 100 consecutive patients. Endoscopy. 2001 Sep; 33(9):786–790. Tringali A, Mutignani M, Perri V, et al. A prospective, randomized multicenter trial comparing DoubleLayer and polyethylene stents for malignant distal common bile duct strictures. Endoscopy. 2003 Dec; 35(12):992–997. Raju GS, Sud R, Elfert AA, et al. Biliary drainage by using stents without a central lumen: a pilot study. Gastrointest Endosc. 2006 Feb; 63(2):317–320. Raju GS, Gomez G, Xiao SY, et al. Effect of a novel pancreatic stent design on short-term pancreatic injury in a canine model. Endoscopy. 2006 Mar; 38(3):260–265. Ishihara T, Yamaguchi T, Seza K, et al. Efficacy of s-type stents for the treatment of the main pancreatic duct stricture in patients with chronic pancreatitis. Scand J Gastroenterol. 2006 June; 41(6):744–750. Reddy DN, Banerjee R, Choung OW. Antireflux biliary stents: are they the solution to stent occlusions? Curr Gastroenterol Rep. 2006 Apr; 8(2):156–160. Giorgio PD, Luca LD. Comparison of treatment outcomes between biliary plastic stent placements with and without endoscopic sphincterotomy for inoperable malignant common bile duct obstruction. World J Gastroenterol. 2004 Apr 15; 10(8):1212–1214. Tarnasky PR, Cunningham JT, Hawes RH, et al. Transpapillary stenting of proximal biliary strictures: does biliary sphincterotomy reduce the risk of postprocedure pancreatitis? Gastrointest Endosc. 1997 Jan; 45(1):46–51. Singh P, Das A, Isenberg G, et al. Does prophylactic pancreatic stent placement reduce the risk of post-ERCP acute pancreatitis? A meta-analysis of controlled trials. Gastrointest Endosc. 2004 Oct; 60(4):544–550. Baron TH. Endoscopic drainage of pancreatic fluid collections and pancreatic necrosis. Gastrointest Endosc Clin N Am. 2003 Oct; 13(4):743–764. Cahen D, Rauws E, Fockens P, et al. Endoscopic drainage of pancreatic pseudocysts: long-term outcome and procedural factors associated with safe and successful treatment. Endoscopy. 2005 Oct; 37(10):977–983. Tham TC, Carr-Locke DL, Vandervoort J, et al. Management of occluded biliary Wallstents.Gut. 1998 May; 42(5):703–707. Baron TH. Endoscopic therapy with multiple plastic stents for benign biliary strictures due to chronic calcific pancreatitis: the good, the bad, and the ugly. J Clin Gastroenterol. 2004 Feb; 38(2):96–98.
19. Pozsar J, Sahin P, Laszlo F, et al. Endoscopic treatment of sphincterotomy-associated distal common bile duct strictures by using sequential insertion of multiple plastic stents. Gastrointest Endosc. 2005 Jul; 62(1):85–91. 20. Kuzela L, Oltman M, Sutka J, et al. Prospective follow-up of patients with bile duct strictures secondary to laparoscopic cholecystectomy, treated endoscopically with multiple stents. Hepatogastroenterology. 2005 Sep–Oct; 52(65): 1357–1361. 21. Kaffes AJ, Hourigan L, De Luca N, et al. Impact of endoscopic intervention in 100 patients with suspected postcholecystectomy bile leak. Gastrointest Endosc. 2005 Feb; 61(2):269–275. 22. Delhaye M, Arvanitakis M, Bali M, et al. Endoscopic therapy for chronic pancreatitis. Scand J Surg. 2005; 94(2): 143–153. 23. Costamagna G, Mutignani M. Pancreatic stenting for malignant ductal obstruction. Dig Liver Dis. 2004 Sep; 36(9):635–638. 24. Lau ST, Simchuk EJ, Kozarek RA, et al. A pancreatic ductal leak should be sought to direct treatment in patients with acute pancreatitis. Am J Surg. 2001 May; 181(5):411–415. 25. Le Moine O, Matos C, Closset J, et al. Endoscopic management of pancreatic fistula after pancreatic and other abdominal surgery. Best Pract Res Clin Gastroenterol. 2004 Oct; 18(5):957–975. 26. Freeman ML, Nelson DB, Sherman S, et al. Complications of endoscopic biliary sphincterotomy. N Engl J Med. 1996 Sep 26; 335(13):909–918. 27. Dolan R, Pinkas H, Brady PG. Acute cholecystitis after palliative stenting for malignant obstruction of the biliary tree. Gastrointest Endosc. 1993 May–June; 39(3):447–449. 28. Kozarek RA. Pancreatic stents can induce ductal changes consistent with chronic pancreatitis. Gastrointest Endosc. 1990 Mar–Apr; 36(2):93–95. 29. Melita G, Curro G, Iapichino G, et al. Duodenal perforation secondary to biliary stent dislocation: a case report and review of the literature. Chir Ital. 2005 May–June; 57(3):385–388. 30. Simpson D, Cunningham C, Paterson-Brown S. Small bowel obstruction caused by a dislodged biliary stent. J R Coll Surg Edinb. 1998 June; 43(3):203. 31. Storkson RH, Edwin B, Reiertsen O, et al. Gut perforation caused by biliary endoprosthesis. Endoscopy. 2000 Jan; 32(1):87–89. 32. Levy MJ, Baron TH, Gostout CJ, et al. Palliation of malignant extrahepatic biliary obstruction with plastic versus expandable metal stents: An evidence-based approach. Clin Gastroenterol Hepatol. 2004 Apr; 2(4):273–285.
163