Cholangioscopy was first performed in the 1970s. We now use the term cholangiopancreatoscopy (CP) to reflect the wider application of these miniature reusable dual-operator “mother-daughter” endoscope systems and now fully disposable and digital single-operator optical catheters for evaluating the biliary or pancreatic duct. Cholangioscopy is an established modality for the management of large biliary stones and for the diagnosis and exclusion of biliary tumors. Pancreatoscopy is increasingly being performed to treat difficult pancreatic duct stones and may be used to distinguish malignant from benign ductal pathology. This review covers available CP technologies, indications, technique, efficacy, and complications.
Key points
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Cholangiopancreatoscopy (CP) is an adjunct to endoscopic retrograde cholangiopancreatography (ERCP) and can be used for the clarification of indeterminate lesions and for guiding therapy of malignancy.
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CP is an established modality in successfully treating difficult pancreaticobiliary stones.
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CP imaging has both fiberoptic and digital technologies and is available in endoscope and catheter-based systems.
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CP is currently widely available, although its use should be limited to those endoscopists who are proficient in performing complex ERCP.
Introduction: nature of the problem
Miniature endoscopes and optical catheters permit direct visualization of the bile and pancreatic ducts. These are usually passed through the working channel of a standard therapeutic duodenoscope during endoscopic retrograde cholangiopancreatography (ERCP).
The first cholangioscope was described in 1941, and the per-oral approach was subsequently introduced in the early 1970s. Per-oral pancreatoscopy (POP) was first described in Japan in 1975. Presently, the 10F platforms provide a working channel, tip deflection, and either fiberoptic or digital/video chips; slim gastroscopes are used without a duodenoscope for direct cholangioscopy.
Introduction: nature of the problem
Miniature endoscopes and optical catheters permit direct visualization of the bile and pancreatic ducts. These are usually passed through the working channel of a standard therapeutic duodenoscope during endoscopic retrograde cholangiopancreatography (ERCP).
The first cholangioscope was described in 1941, and the per-oral approach was subsequently introduced in the early 1970s. Per-oral pancreatoscopy (POP) was first described in Japan in 1975. Presently, the 10F platforms provide a working channel, tip deflection, and either fiberoptic or digital/video chips; slim gastroscopes are used without a duodenoscope for direct cholangioscopy.
Indications/Contraindications
For indications and contraindications to cholangiopancreatoscopy, see Table 1 .
| Indications | Contraindications |
|---|---|
|
|
Technique/Procedure preparation
Sedation
General anesthesia is recommended. Intraductal irrigation can lead to reflux of fluids and pooling within the stomach, increasing the risk of aspiration. For “mother-daughter” systems, trained secondary personnel (ie, a registered nurse, technician, or assisting endoscopist) handle the “daughter” scope.
Antibiotic Prophylaxis
Preprocedural broad-spectrum intravenous antibiotic prophylaxis is recommended due to a potentially higher rate of cholangitis when compared with those patients undergoing ERCP without cholangioscopy.
Patient Positioning
We prefer the semiprone position.
Equipment
Systems available in the United States for cholangioscopy include endoscope-based dual-operator systems, commonly referred to as “mother-daughter” (Olympus America, Center Valley, PA, and Pentax, Montvale, NJ) and a catheter-based system, commonly referred to as “single-operator” cholangioscopy (SpyGlass DS Direct Visualization System, Boston Scientific Endoscopy, Marlboro, MA). In addition, cholangioscopy can be performed using a slim (4.9–5.9 mm outer diameter) gastroscope or even standard gastroscope in patients with a dilated common bile duct.
Fiberoptic cholangioscopes range in diameter from 3.1 to 3.4 mm, with a working channel of 1.2 mm that permits passage of forceps and lithotripsy fibers, and have up/down tip deflection. Video cholangioscopes are prototypes. The fully disposable single-operator catheter-based system is approved by the Food and Drug Administration for pancreatic duct inspection, has 4-way tip deflection, a 1.2-mm working channel diameter, and two 0.6-mm irrigation ports. Pancreatoscopy is primarily performed with scopes and catheters designed for inspection of the bile duct. A detailed review of the available cholangiopancreatoscopes has been summarized in a technical status evaluation report by the American Society of Gastrointestinal Endoscopy’s Technology committee and other technical reviews.
Slim gastroscopes (5–6-mm diameters) can be used in patients with dilated common bile ducts generally larger than 10 mm in diameter. The larger working channel accommodates argon plasma coagulation probes, larger biopsy forceps, and lithotripsy fibers. Insufflation with sterile saline, water, or CO 2 is preferable, as air insufflation has been associated with air embolism.
Technique
Scope insertion
CP is carried out during ERCP, and generally following cholangiopancreatography to map the target areas. A long (450-cm) 0.035-inch guidewire is advanced to the intrahepatics or pancreatic tail and the cholangiopancreatoscope is advanced over the guidewire through a therapeutic duodenoscope. For endoscope-based systems, a “transfer tube” is placed into the biopsy port to allow wire exit from the working channel to permit counter-traction to help minimize duodenoscope elevator use. Sphincterotomy and/or stricture dilation are performed, unless the orifice is patulous, to facilitate scope passage. If a slim gastroscope is being used, it may be inserted into the duct over a guidewire placed during ERCP or by way of a free-hand technique. Pediatric forceps may be used to gently grasp intraductal mucosa or prototype anchoring balloons to permit advancement of the slim gastroscope toward the intrahepatics. For the single-operator catheter-based system, the endoscopist has control of the 4-way steering dials and may periodically lock the dials for fine movements of the catheter to stabilize visualization of a target during biopsy.
Once the cholangioscope is advanced to the desired location within the duct, the guidewire is removed to enhance visualization and to permit use of the working channel.
Narrow duct diameters or tight strictures complicate or prohibit scope passage. Circumferential visualization also may be compromised in the evaluation of a markedly dilated duct.
The angle to the pancreatic orifice from the duodenoscope is more oblique than compared with the bile duct, and initial transpapillary advancement is often simpler than traversing the biliary orifice, which is often at a right angle. However, traversing the minor papilla is more difficult due to acute angulation. To negotiate downstream narrowed caliber ducts, dilation with a 4-mm or 6-mm balloon before attempting device introduction may be required. The inherent angulation at the relatively fixed genu may limit circumferential inspection of the area.
Techniques to improve visualization
Irrigation rates should be kept as low as possible to permit sufficient view. Periodic duodenoscope suctioning and aspiration using the CP is encouraged. For the digital catheter-based system, a separate port for suction via the working channel can be attached to wall suction. This is effective even when devices such as biopsy forceps or electrohydraulic lithotripsy (EHL) are present in the working channel (Shah, personal observation, 2015). The endoscope-based fiberoptic systems also have suction capability. A “closed circuit” technique of irrigation and suctioning in the catheter-based system may be used to reduce debris obscuring visualization.
Intraductal Lithotripsy
EHL or laser lithotripsy can be used to treat large bile and pancreatic duct stones under direct visualization. EHL has 2 coaxially insulated electrodes ending at an open tip. During water immersion, sparks are generated that produce high-amplitude hydraulic pressure waves for stone fragmentation. A generator produces a series of high-voltage electrical impulses at a frequency of 1 to 20 per second, with power settings ranging from 50% to 100%. The tip of the EHL fiber should protrude no more than 2 to 3 mm from the scope and be positioned en face with the stone. Pulsed laser is transmitted via a flexible quartz fiber through the working channel of the cholangioscope. The application of repetitive pulses of laser energy to the stone leads to the formation of a gaseous collection of ions and free electrons of high kinetic energy (eg, plasma). Absorption of the laser energy rapidly expands and collapses the plasma, inducing a spherical mechanical shockwave between the laser fiber and stone, leading to stone fragmentation.
Intraductal Biopsy
Two methods can be used to obtain targeted biopsies from the bile or pancreatic duct: CP-directed biopsy and CP-assisted biopsy. CP-directed biopsy is performed by passing a miniature biopsy forceps under direct visualization. For CP-assisted biopsy, the target site is localized using CP visualization and a fluoroscopic spot film of the CP tip positioned at the lesion. After CP removal, a biliary or conventional biopsy forceps is passed through the working channel of the duodenoscope alongside the guidewire to obtain tissue samples under fluoroscopic guidance.
Device insertion suggestions
If there is failure to pass accessories through the CP channel, withdrawing the CP to the distal duct, advancing the device, followed by advancement of the CP may be helpful to traverse the angulation between the elevator and the orifice. Alternatively, advancement of the CP toward the bifurcation may also facilitate device passage. For the disposable catheter-based system and forceps passage, rapid open and closure of the forceps when resistance is encountered can be helpful. This is not recommended for endoscope-based systems because of the potential for damage to the working channel. If the target lesion is distal, passage of the miniature forceps or lithotripsy fiber may be difficult and CP-assisted biopsies can be obtained or preloading of fibers followed by free-hand cannulation, respectively.
Complications and management
Complications specific to the performance of cholangiopancreatoscopy include cholangitis, which is related to intraductal fluid irrigation, and, uncommonly, hemobilia and bile leaks attributable to intraductal lithotripsy. Our center retrospectively assessed patients undergoing ERCP with or without cholangiopancreatoscopy and found that CP had higher consensus complications (pancreatitis, perforation, cholangitis, or bleeding; 4.2% vs 2.2%), and specifically postprocedural cholangitis (1.0% vs 0.2%). For pancreatoscopy, it is likely that higher rates of pancreatitis may be seen that are inherent to pancreatic endotherapy.
Postoperative care
When cholangioscopy is performed in the setting of hilar or intrahepatic strictures or leaks, we recommend the use of postprocedural antibiotics for 5 to 7 days as prophylaxis of cholangitis and infection, respectively. Further, for index pancreatic endotherapy to include sphincterotomy, therapeutic stenting, and intraductal lithotripsy, we generally recommend postprocedure 23-hour observation and judicious periprocedural intravenous fluids.
Reporting, follow-up, and clinical implications
Cholangioscopy findings are included in a separate paragraph in the ERCP report. In the highly suspicious clinical setting, if malignant findings are suggested based on cholangioscopy visualization, surgical resection may be recommended. If the examination is equivocal for malignancy and tissue sampling is nondiagnostic, a close interval for repeat tissue sampling is planned. For pancreatoscopy, we recommend prophylactic stenting.
Outcomes
Cholangioscopy Outcomes
Bile duct stones
Preliminary data from our center categorized complex biliary stones that required endoscopic papillary large balloon dilation, mechanical lithotripsy, or intraductal lithotripsy. There were 211 patients with primarily extrahepatic stones who required these advanced techniques, and complete clearance was achieved in 99%; 79% at index ERCP and 20% at subsequent ERCP. Patients in the intraductal lithotripsy group had significantly larger stones. CP is less successful with associated strictures or intrahepatic stones ( Fig. 1 , Table 2 ).
| Author (n = Number of Patients) | Location of Stones and Method (EHL or LL) | Clearance, % | Morbidity, % |
|---|---|---|---|
| Chen et al, 2011 (66) ∼15 Centers | Mostly extrahepatic (EHL and LL) | 92 | Variable |
| Patel (69) 4 Centers | Extrahepatic/Intrahepatic (LL) | 97 | 4 |
| Arya et al, 2004 (94) | Extrahepatic/Intrahepatic (EHL) | 90 | 17 |
| Farrell et al, 2005 (26) | Extrahepatic (EHL) | 100 | 0 |
| Maydeo et al, 2011 (60) | Extrahepatic (LL) | 100 | 14 |
| Piraka et al, 2007 (32) | Extrahepatic/Intrahepatic (EHL) | 81 | 6 |
| Sepe et al, 2012 (13) | Cystic duct (EHL) | 77 | 0 |
| Okugawa et al, 2002 (36) | Intrahepatic (EHL); 1/3 had ESWL | 64 | 3 |
| Neuhaus et al, 1998 (60) | Extrahepatic: ESWL vs LL | 73 vs 97 ( P <.05) | 7 |
Related posts:
Difficult Biliary Access
Endoscopic Retrograde Cholangiopancreatography for the Management of Common Bile Duct Stones and Gallstone Pancreatitis
Endoscopic Retrograde Cholangiopancreatography in Surgically Altered Anatomy
Preventing Postendoscopic Retrograde Cholangiopancreatography Pancreatitis
Endoscopic Treatment of Recurrent Acute Pancreatitis and Smoldering Acute Pancreatitis
Sphincter of Oddi Dysfunction
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