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Endoscopy 2017; 49(01): 5-7
DOI: 10.1055/s-0042-120323
Editorial
© Georg Thieme Verlag KG Stuttgart · New York

Advanced biliary access techniques: is the double-guidewire technique considered a “Wednesday’s child”?

Refering to Tse F et al. p. 15–26
Phonthep Angsuwatcharakon
1   Department of Anatomy, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
2   Division of Gastroenterology, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
,
Pradermchai Kongkam
2   Division of Gastroenterology, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
,
Rungsun Rerknimitr
2   Division of Gastroenterology, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
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Publikationsdatum:
09. Januar 2017 (online)

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Selective biliary cannulation is used as a gateway for therapeutic biliary endoscopy. The average success rate of biliary cannulation procedures using conventional cannulation techniques is 90 % (range 70.6 % – 98.9 %); on average, 10 % of the biliary cannulations performed can be considered to be difficult, requiring more advanced techniques to allow deep cannulation [1]. Currently, there are many advanced techniques available, including precut sphincterotomy, transpancreatic septotomy (TPS), the double-guidewire technique (DGT), and cannulation over a pancreatic stent [2].

Precut sphincterotomy is commonly used as a salvage technique after failed conventional cannulation. The rate of utilization of precut sphincterotomy is reported to be 10 % according to a recent meta-analysis [1]. Precut sphincterotomy is generally considered to be hazardous because of the reported risk of post-endoscopic retrograde cholangiopancreatography (post-ERCP) pancreatitis (PEP) [2], bleeding, and perforation [3], as compared with conventional cannulation. If serious complications are to be avoided, precut sphincterotomy technically requires precise control of the needle-knife when making an incision from or towards the papilla. Therefore, it is recommended that precut sphincterotomy be performed by experts [3] as it requires a steep learning curve and performance of a large number of cases to achieve acceptable rates of deep cannulation and low complication [4] [5]. Types of precut sphincterotomy are needle-knife papillotomy (NKP) and needle-knife fistulotomy (NKF). NKP is an upward incision starting from the orifice of the major duodenal papilla, whereas in NKF the incision does not directly involve but avoids injury to the pancreatic orifice, usually starting from a few millimetres proximal to the orifice of the major duodenal papilla. TPS, a variant of precut sphincterotomy, is a technique for deroofing the distal bile duct mucosa: while the guidewire is in the pancreatic duct, a sphincterotome is used to cut towards the direction of the bile duct (10- to 12-o’clock position).

The risk of PEP has been reported to be lower with NKF than with NKP [6] Additionally, data from a meta-analysis show that early precut sphincterotomy, if it is performed by experts, can also reduce PEP in difficult cannulations [7]. On the other hand, nonexpert endoscopists and those with low case volume are reluctant to perform precut sphincterotomy as an earlier study showed that precut sphincterotomy performed by nonexperts had lower success rates and higher rates of complications [5].

In normal human anatomy, the pancreatic duct is more perpendicular to the duodenal wall than is the bile duct; hence inadvertent pancreatic duct cannulation occasionally occurs during attempts at biliary cannulation. The DGT involves the application of two guidewires to achieve deep biliary cannulation. The DGT is usually commenced after one or a few inadvertent pancreatic duct passage(s) by a guidewire; that guidewire is left in the pancreatic duct while a catheter preloaded with the second guidewire is used for the biliary cannulation and aimed towards the 11-o’clock position of the first guidewire. The first guidewire acts as a landmark for the biliary orifice and straightens the floppy common duct. Unlike precut sphincterotomy, the DGT requires only a small learning curve for practitioners to become expert [8]. From the present authors’ observations, after a dozen DGT practice attempts, trainees can perform deep biliary cannulation without help from more senior endoscopists. Therefore for nonexpert endoscopists, the DGT is likely to be the preferred technique after a failed conventional cannulation. Currently, the DGT is recommended by the European Society of Gastrointestinal Endoscopy (ESGE) as an alternative technique for difficult biliary cannulation after repeated inadvertent pancreatic duct cannulations [2]. Nevertheless, the risk of PEP is a concern [9], hence temporary placement of a pancreatic stent is recommended whenever these techniques are being used [2]. In addition, a pancreatic stent may be used as a platform for a second wire instead of landing on top of the first guidewire as in the case of the DGT. Of note, for deep biliary cannulation, the results for cannulations over pancreatic stents are comparable to those using the DGT [10]. In some circumstances, the pancreatic stent might occlude the ampullary orifice and preclude biliary cannulation, especially when the papilla is not widely open, and in this case precut sphincterotomy over the pancreatic stent may be required to achieve biliary cannulation.

In this issue of Endoscopy, Tse et al. report a systemic review and meta-analysis of the DGT, including 577 patients from 7 randomized controlled trials (RCTs) [11]. All the studies included patients with difficult biliary cannulation according to a variety of definitions and used the DGT as one arm. The cannulation techniques in the other arms were persistence with conventional cannulation, precut sphincterotomy or TPS, and cannulation over a pancreatic stent. The PEP rate was significantly increased for DGT compared to the other techniques (risk ratio [RR] 1.98, 95 % confidence interval [95 %CI] 1.14 – 3.42), and the number-needed-to-treat for an additional harmful outcome (NNTH) was 13. Subgroup analyses based on the comparison techniques, including persistent conventional cannulation (n = 305), precut sphincterotomy or TPS (n = 115) and cannulation over a pancreatic duct stent placement (n = 157), demonstrated that PEP in the DGT group was significantly higher than PEP in the precut sphincterotomy/TPS group. There was no difference (P = 0.53) and low heterogeneity (I 2 = 15 %) among the subgroups. More importantly, the study demonstrated that DGT was not superior to the other techniques in terms of successful cannulation of the common bile duct. Statistics suggested that DGT was a more harmful technique without additional benefits when compared to the others.

However, when we consider the details of each of the techniques, they differed in the amount of the PEP contribution, and the risk of PEP was not homogeneous among several techniques. In fact, a study from China that compared TPS vs. DGT was the only study that demonstrated a significantly higher rate of PEP in the DGT group [12]. The other 5 studies that compared DGT with the other techniques did not demonstrate a significant difference for PEP rates [8] [10] [13] [14] [15]. In addition, this meta-analysis demonstrated that use of the DGT increased only the rate of mild PEP when compared to the other techniques, and that there were no significant differences in the rates of moderate and severe PEP, that were reportedly low. This may reflect the expertise of the senior endoscopists who were involved in those studies. Tse et al. note that none of the included studies reported the use of rectally administered nonsteroidal anti-inflammatory drugs (NSAIDs) as a measure to reduce the rates of PEP [11]. Of note, one of the included studies [13] that used pancreatic duct stenting in both groups showed no significant differences in PEP rates.

Regardless of which advanced technique is used, our opinion, which concurs with ESGE recommendations [2], is that all of these patients with difficult cannulation should be provided with these prophylactic measures regarding PEP because such patients are considered to be at high risk for PEP.

If we think of all the various advanced techniques to achieve deep biliary cannulation as being our children, perhaps the DGT is a “Wednesday’s child” that could be born to any family, including a family with inexperienced parents. Unlike the lyric of the nursery rhyme, this Wednesday’s child is not “full of woe.” On the contrary, we think that the DGT is one of the important members of our family, not a problem child but rather one that may help others when the family is in trouble. Even in the hands of inexperienced parents, this Wednesday’s child is easy to raise. For the best outcomes, prophylactic measures such as pancreatic duct stenting and/or NSAID administration should be hired as a special caretaker. Needless to say, the DGT is a child that should not be abandoned, as this child may save you in regard to difficult cannulation procedures.