Precut sphincterotomy for selective biliary duct cannulation during endoscopic retrograde cholangiopancreatography.

Selective biliary cannulation during endoscopic retrograde cholangiopancreatography (ERCP) is required to perform all therapeutic biliary procedures. Despite major advances in imaging, guidewires and sphincterotome catheter designs, the success rate for biliary cannulation by experienced endoscopists during ERCP is approximately 85% when standard cannulation techniques are applied. Precut sphincterotomy, also known as access sphincterotomy, is performed when standard techniques fail to achieve selective biliary cannulation. Precut sphincterotomy significantly increases the rate of biliary cannulation up to 98%. However, precut sphincterotomy has traditionally been considered a risk factor for adverse events following ERCP, especially concerning is post-ERCP pancreatitis which results in significant morbidity and financial burden. Recent evidence suggests that precut sphincterotomy alone may not be a risk factor for pancreatitis; rather repeated attempts ( ≥ 10) at biliary cannulation prior to precut sphincterotomy may be the actual cause of post-ERCP pancreatitis. In this paper, we review the different variations of the precut sphincterotomy technique and their corresponding rates of success and adverse events.

Introduction and brief history of precut sphincterotomy

It has been more than half a century since McCune et al reported the first endoscopic cannulation of the major duodenal papilla in 1968 at George Washington University [1]. In 1974, the first successful cases of endoscopic biliary sphincterotomy were reported nearly simultaneously by Classen and Demling in Erlangen, Germany [2]; and by Kawai et al in Kyoto, Japan [2,3]. In both reports, impacted gallstones were removed, thereby transforming endoscopic retrograde cholangiopancreatography (ERCP) from a diagnostic to a therapeutic procedure, which would eventually become the preferred minimally invasive method for the treatment of pancreaticobiliary diseases. Despite improvements in endoscopes and imaging, which include multilumen flexible video endoscopes, high-definition wide screen displays, guidewires and accessories, selective biliary cannulation (SBC) using standard techniques has not become uniform, and ranges from 80 to 95% depending on the experience of the endoscopist and the anatomy of the particular patient [4,5].

Precut sphincterotomy (PS), also referred to as access sphincterotomy, was initially developed in the late 1970s and early 1980s as a technique to improve successful biliary cannulation when standard techniques fail [6-8]. The basic technique for PS has evolved much since its introduction, and now includes three widespread techniques, with many variations and modifications of the procedure [5,9]. The decision to use one type of PS over another is based upon patient anatomy and endoscopist experience.

Osnes and Kahrs performed the first reported ‘Precut’ by creating what they called a choledocho-duodenostomy, with the use of a diathermy snare (Classen-Demling snare) to extend the size of pre-existing choledochoduodenal fistulae which then allowed spontaneous passage of common bile duct (CBD) stones [8]. Shortly thereafter in 1978, Caletti et al, performed the first precut fistulotomy (PF), when they created the first de novo choledochoduodenal fistulae in cases of difficult biliary cannulation [6].

A ‘Precut’ is defined as an incision into the ampulla of Vater or CBD made prior to gaining SBC during ERCP, and is a technique used to facilitate SBC. The term ‘Precut’ appears to have been coined by Siegel in 1980, in the context of reporting the new method of precut papillotomy (PP) with the use of a sphincterotome [7]. During the procedure he was unable to cannulate the CBD, however he began cutting into the duodenal papillary orifice prior to, and to facilitate cannulation of, the CBD.

‘PS’ has now come to signify a broad range of procedural techniques whereby a controlled surgical incision is created, with the goal of cannulating the CBD. There have been many subtle modifications with regard to the techniques and equipment by which PS is preformed [5,9]. However, a standardized classification and nomenclature system does not exist for PS, which has resulted in confusion among physicians and researchers as to the definition and actual performance of PS techniques. For example, some authors have used the terms ‘sphincterotomy’ or ‘papillotomy’ to describe what is actually the creation of a ‘fistulotomy’ (choledochoduodenal fistulotomy) which, by definition, avoids the papillary orifice, leaving the papillary sphincter at least partially intact.

We propose a classification of the types of PS to allow for standardization of the lexicon with which precut techniques are performed, to create a common nomenclature system to describe new modifications, and importantly to allow for accurate comparison of variations and modifications of the major techniques. In the case of normal anatomy (Fig. 1), all PS techniques fall into 3 broad types based upon the anatomy that is divided to reach the underlying ductal or ampullary system (Table 1). This nomenclature is constant regardless of the type of equipment used, and theoretically may be used in the rare event that the pancreatic duct (PD) is unable to be cannulated, but biliary cannulation is successful.

Figure 1

Normal anatomy of the major duodenal papilla

Table 1

Mayo Clinic Precut Sphincterotomy Classification System

Standard technique for selective biliary cannulation

The most accepted standard technique (Fig. 2) for achieving SBC during ERCP begins with placing the duodenoscope in the short axis position with the tip of the endoscope in the second portion of the duodenum. The ampulla of Vater is positioned in the left upper quadrant of the endoscopic view, orienting its long axis toward the right lower corner of the endoscopic field. Most endoscopists begin cannulation with an Erlangen-type sphincterotome, or a traction sphincterotome (also known as pull-type sphincterotome), which is preloaded with a guidewire to aid in cannulation of the CBD and to facilitate therapeutic procedures. The tip of the sphincterotome is engaged into the orifice of the major duodenal papilla, and is then slightly flexed so that it is aligned with the axis of the ampulla. As an adjunct contrast injection may be used to facilitate fluoroscopic visualization of the ductal anatomy. After initial superficial insertion of the sphincterotome, the guidewire is advanced into the bile duct and the sphincterotome is relaxed using an upward turning motion of the big wheel of the endoscope. Use of a guidewire to assist in attempting SBC has been shown in several studies to decrease the rate of adverse events such as post-ERCP pancreatitis (PEP) when compared to the use of contrast alone [25-27]. In a recent systematic review of 7 randomized controlled trials, which compared cannulation techniques using a guidewire versus contrast injection, the risk of PEP was significantly reduced when a guidewire was used (3.2% versus 8.7%; RR 0.38, 95% CI 0.19–0.76) [28].

Figure 2

Standard ERCP technique for biliary cannulation

When standard cannulation techniques fail, additional options exist with regard to the type of guidewire used. One such option is the use of a small angulated-tip hydrophilic guidewire, such as is commonly used for intravascular procedures. This specialized guidewire is used to probe the ampullary orifice and rotating it clockwise and counterclockwise to permit the guidewire to self-align with the bile duct. The use of a hydrophilic guidewire has been shown to increase the success of biliary cannulation up to 98% [5,29].

In the hands of experienced endoscopists, the time spent in attempting primary SBC with a wire-guided sphincterotome is approximately 5 min and requires only a few attempts. Difficult SBC is a subjective term, though has been defined by some as requiring more than 10 min and/or ≥10 attempts to achieve cannulation [30,31]. If the described steps fail to achieve selective cannulation of the CBD, experienced endoscopists often use PS. Prior to performance of PS additional options to attain SBC must be considered, to include: repeat attempts by the same endoscopist at a different session, repeat attempts by another endoscopist at the same or a different occasion, and percutaneous versus endoscopicultrasound-guided biliary access.

In cases where biliary cannulation fails with the use of a guidewire, PD cannulation is often easily achieved [32]. In such cases, placement of a pancreatic stent may increase the biliary cannulation rate and obviate the need for PS [33,34]. After several unsuccessful attempts to achieve SBC with a guidewire, a soft plastic stent (generally 3-5 French, and 2-8 cm in length) is placed in the main PD to assist cannulation of the bile duct while reducing the risk of PEP [33,35-39].

Pancreatic stent placement to facilitate cannulation was evaluated in patients in who attempted SBC failed with the use of a guidewire. In a retrospective cohort study Cote et al reviewed the charts of 2,345 patients undergoing ERCP; 76 patients had native papilla in which traditional and guidewire-assisted approaches failed. Successful cannulation was achieved in 60/76 (78.9%). The authors then preformed PS over the pancreatic stent in the remainder (n=16) which resulted in an overall success rate of 93.4% (71/76) while maintaining an overall PS rate of 19% (16/76) [33].

Post-ERCP pancreatitis

PEP is the most common and serious complication of ERCP [40]. Since the consensus definitions by Cotton et al in 1991, and revisions in 2010; PEP has been defined as the development of typical abdominal pain with amylase ≥3X the upper limit of normal, and requiring unplanned hospital admission, or prolongation of admission by at least 1 day [41,42]. The development of PEP results in a significant increase in the global cost of care. Based on Medicare cost estimates in 2005, the cost of ERCP with PD stenting was $1952 compared to $5687 for the care of patients with PEP [43].

In a systematic review of 21 prospective studies, which included 16,885 patients undergoing both diagnostic and therapeutic ERCP, Andriulli et al found the overall rate of PEP was 3.5%, with a corresponding mortality rate of 0.8% [44]. Patients who are considered to be high-risk for development of PEP were identified in a meta-analysis by Macsi et al as patients with suspected sphincter of Oddi dysfunction (RR 4.09, 95% CI 3.37-4.96; P <0.001), female gender (RR 2.23, 95% CI 1.75-2.84; P <0.001), and those with a previous history of pancreatitis (RR 2.46, 95% CI 1.93-3.12; P <0.001); additional procedure-related risk factors for PEP were PS (RR 2.71, 95% CI 2.02-3.63; P <0.001) and pancreatic injection (RR 2.2, 95% CI 1.6-3.01; P <0.001) [37].

In a randomized controlled trial involving 70 patients, Ito et al demonstrated a significant reduction in the rate of PEP from 23% to 2.9% with the use of PD stents [39]. In a metaanalysis of five controlled trials involving 481 patients Singh and colleagues demonstrated that the use of pancreatic stents reduced the incidence of PEP in high-risk patients from 15.5% to 5.8%; furthermore, the study determined that pancreatic stent placement was successful in 93% of patients [38]. Some endoscopists prefer to remove the internal flange of the pancreatic stent to enable its spontaneous passage following the procedure [45]. Once a pancreatic stent is properly placed, the endoscopist may repeat attempts to cannulate the CBD. If further attempts at SBC are unsuccessful, PS may be performed (Fig. 3).

Figure 3

Precut fistulotomy with the aid of a pancreatic duct stent

Precut sphincterotomy techniques

The use of PS access techniques requires an understanding of the anatomy of the biliary and pancreatic ductal system. No consensus exists about the optimal alternative procedure in cases of failed biliary cannulation using standard techniques [13]. As such, there have been multiple PS techniques described, and many variations and modifications to these techniques. The most common PS techniques that are performed are the PP, PF and the transpancreatic PS (TPS) [5,11,40].

Precut papillotomy

PP is performed, most commonly, by using a needle-knife (Fig. 4) to carefully dissect the major duodenal papilla in a layer-by-layer fashion to directly visualize and cannulate the CBD. The endoscopist initiates the papillotomy by placing the needle-knife at upper portion of the papillary orifice, near the 12 o’clock position, and initiates the cut upwards from the orifice, or downwards through the papillary sphincter. The incision is extended by cutting in 1-2 mm increments with short-pulses of cutting current (usually with a controlled generator) to de-roof the common biliary duct orifice [46]. Once the biliary sphincter muscle is exposed (it is identified by its whitish, onion-skin appearance) the papilla may be cannulated or the biliary sphincter may be transected, followed by cannulation of the CBD.

Figure 4

Precut papillotomy

Precut fistulotomy

An alternative method to perform a precut is via PF (Fig. 5). This technique commonly employs a needle-knife to create an incision at the level of the intraduodenal segment of the CBD, which runs proximal to the major duodenal papilla. The incision is begun above the papillary orifice, is then extended either upward in the cephalic direction, or downward toward the papillary orifice. This approach leaves the papillary orifice intact and creates a fistulotomy for direct visualization of the CBD and facilitates SBC (Fig. 6). The success rate of biliary cannulation using the PF technique is up to 98% [5].

Figure 5

Precut fistulotomy

Figure 6

Precut fistulotomy. The major duodenal papilla is visible below the prominent mucosal fold. A peri-ampullary diverticula is present in the left upper corner

After performing PP or PF, a guidewire may be passed into the biliary duct, then additional extensions of the incision can be made by using a standard sphincterotome. Extension of the incision may be especially useful for removal of large bile duct stones (≥15 mm). In addition or alternatively, the sphincterotomy/fistulotomy tract may be dilated with a large diameter balloon, which is matched to the size of the stone and/or the diameter of the proximally dilated bile duct. Endoscopic papillary large balloon dilation following PS has been shown to be safe and effective [47].

Transpancreatic precut sphincterotomy

The TPS technique (Fig. 7) was first reported in 1995 by Goff as a technique that may be performed after attempts at SBC have led to guidewire passage into the PD [22-24]. The TPS technique uses a standard “traction-type” sphincterotome, which is oriented in the direction of the CBD at approximately the 11 o’clock position, and is then inserted superficially into the PD. The incision is then made to expose the bile duct orifice or the bile duct itself. Once the pancreatic sphincter and major duodenal papilla are cut, biliary cannulation may be re-attempted [22,48,49]. The potential advantages of the TPS include: it is not necessary to exchange the sphincterotome for a needle-knife device; and the depth of incision is more easily controlled, thus the risk of perforation is theoretically lower [50]. The use of a PD stent after TPS has been shown to reduce the incidence of PEP [51].

Figure 7

Transpancreatic precut sphincterotomy

Additional variations of precut sphincterotomy

The Erlangen PP (EPP), also known as Papillary Roof Incision, is a subtype of the PP technique that takes its name from the ‘birthplace’ of endoscopic sphincterotomy in Erlangen, Germany [52]. Instead of using a needle-knife to incise the papillary sphincter, the papillotomy is performed using an Erlangen-type sphincterotome which lacks a “nose” such that the cutting wire extends to the tip of the sphincterotome [5,16,17,52]. The procedure was pioneered by Soehendra and colleagues, who performed a randomized control trial comparing outcomes in 146 patients who underwent conventional sphincterotomy with use of a guidewire (CSG) versus 145 patients who underwent primary EPP [53]. The authors found that biliary cannulation failed in 42 patients (28.8%) in the CSG group, after which secondary EPP was successful in 41 of these patients, leading to an overall success rate of 99.3%. Most notably, the success rate using primary EPP was 100% at the first attempt, and cannulation was achieved 1.4 min faster than in the CSG group (P <0.001; 6.9±1.8 min versus 8.3±2.1 min). The adverse event rates in both groups were similar, including the incidence and severity of pancreatitis (2.9% CS group vs. 2.1% EPP group; P >0.05). None of the study patients developed severe hemorrhage, pancreatitis or perforation leading the authors to conclude that primary precut using EPP was possibly faster and at least as safe and successful as CSG.

Intramural incision, initially described by Burdick et al, is a PP variation that may be useful when standard attempts at SBC with a guidewire have lead to the creation of a false tract through the intraduodenal segment of the bile duct (Fig. 8) [54]. This pseudo-tract is then incised with the sphincterotome (Fig. 9), or with a needle-knife, thereby unroofing and exposing the bile duct and allows for direct visualization of both the pancreatic and biliary sphincters [55,56]. Intramural Incision makes use of an otherwise unplanned event to gain biliary or PD access, or to retrieve fractured stents [57,58].

Figure 8

Precut papillotomy via intramural incision. The guidewire is noted to have inadvertently passed through the mucosa of the intraluminal portion of the major duodenal papilla. Incision of the mucosa using the sphincterotome will follow

Figure 9

Precut papillotomy via the intramural incision. The sphincterotome is used to incise the intraluminal portion of the major duodenal papilla following the guidewire's path

Supra-Papillary Puncture is an evolving subtype of PF [6,12]. This technique creates direct duodenocholedochal access with the use of a specialized catheter fitted with a needle to directly puncture the biliary duct under fluoroscopic guidance, without the use of cautery. Data on the technique are thus far limited; however it may offer a reduced rate of PEP but potentially a higher rate of perforation [59-61]. Endoscopic ultrasound may be a useful adjunct in lowering the rate of adverse events using this technique [62,63].

Supra-Papillary Blunt Dissection is another PF subtype that is similar to Supra-Papillary Puncture. This technique utilizes a cotton “peanut” to bluntly dissect the supra-papillary mucosa and allows for direct visualization and puncture of the CBD [13].

Comparing timing and techniques

Regardless of the technique used, historically PS has been considered as a high-risk, technically difficult procedure, which should only be performed by very experienced endoscopists [4,74,75]. There have been many studies that report or evaluate the success and complications associated with PS. For direct comparison of the date from selected major PS studies, please see Table 2.

Table 2

Selected Precut Technique Studies

Recent data suggest that PS is a safe, timesaving and effective technique [30,31,64]. Some have suggested that endoscopists should have completed at least 200 diagnostic ERCPs under supervision, with SBC rates of 80-85% before performing endoscopic biliary sphincterotomy [76,77]. The number of ERCPs that one should perform before attempting PS is unknown. Based upon data accumulated by one endoscopist, it appears despite a decrease in need to perform PS to obtain cannulation, as well as an increase in success rate of PS, the adverse event rate remains stable with increasing experience [4]. This suggests there is an inherent risk of PS that cannot be eliminated.

As previously mentioned, there have been several publications showing that PS is an independent risk factor for adverse events following ERCP such as PEP, cholangitis, perforation and bleeding [78-80]. On the other hand, the precut technique itself may not be responsible for adverse events, but higher rates of adverse events may be due to using it as a last resort after prolonged attempts at biliary cannulation [10,30,81,82]. Adverse events following PS may be the result of use of cautery and/or trauma from excessive manipulation/repeated cannulation attempts which is thought to impair drainage of the pancreas as a result of papillary edema [40,75,82]. Further, perforation of PD side branches from passage of guidewires and/or overfilling of the PD may also result in pancreatitis [69,80].

Precut sphincterotomy versus standard cannulation techniques

Few studies have directly compared PS versus standard cannulation techniques, the PS data from selected studies are presented in Table 2. In a meta-analysis of six prospective, randomized controlled trials that included 959 patients, Gong et al attempted to establish the efficacy and safety of PS (using both PP and PF techniques) when compared to conventional biliary cannulation techniques [83]. The main outcomes assessed were rates of successful biliary cannulation and adverse events. The pooled analysis showed a trend toward higher rates of SBC with the use of PS (89.3% versus 78.1%), however this trend was not statistically significant for successful primary biliary cannulation with PS [OR 2.05 (95% CI 0.64–6.63)]. In addition the use of precut significantly reduced the risk of PEP (RR) of

0.46 (95% CI: 0.23–0.92) compared to standard techniques. By maintaining pancreatic flow using small diameter prophylactic PD stents, the risk of PEP can be decreased, especially with regard to the risk of severe PEP [20,84-88].

In a prospective study of 116 patients undergoing ERCP the efficacy of TPS to obtain biliary access after standard methods had failed was compared to conventional biliary sphincterotomy [71]. Immediate biliary access after TPS was achieved in 85% of cases; adverse events occurred in 12%, consisting of post-sphincterotomy bleeding in 2.6%, PEP in 8%, and retroperitoneal perforation in 1.7%, the latter of which were managed conservatively. The authors found that the amount of time between completing the PS and obtaining initial biliary access was the most important factor associated with successful biliary cannulation.

Precut papillotomy versus precut fistulotomy

There are little comparative data on the efficacy and safety of PP and PF, the two most widely used PS techniques (Table 3).

Table 3

Comparison of Precut Techniques [10,11,21,89]

In a randomized comparative study of 153 patients with suspected choledocholithiasis, Mavrogiannis et al compared patients who underwent PF (n=74) to patients who underwent PP (n=79) [10]. Their analysis determined that patients who underwent PF had a reduced incidence of PEP with respective rates of 0% versus 7.59% with PP (P <0.05).

In a retrospective cohort study of patients undergoing ERCP at Mayo Clinic, Rochester the outcomes of 139 consecutive patients were assessed [11]. The same endoscopist performed the precut technique used in each of three groups. Forty-four patients underwent PF with occasional PD stenting (6 of 44), 47 patients received PP without PD stenting, and 48 patients received PP with frequent PD stenting (15 of 48). The success rate of each type of PS was 95.5%, 95.7%, and 89.6% respectively at initial ERCP, and 100%, 97.8%, and 95.6% after a second ERCP. A non-significant trend toward a lower incidence of PEP occurred in the PF group compared with the PP techniques (0%, 6% and 3%). The finding that PF may reduce the risk of PEP could be due to the fact that fistulotomy technique avoids the papillary orifice, whereas PP causes trauma and cautery effect/edema to the pancreatic orifice, which may result in subsequent poor drainage of the pancreas. As stated previously, the latter can be prevented with placement of a prophylactic PD stent.

Transpancreatic precut sphincterotomy versus precut papillotomy/fistulotomy techniques

In a retrospective analysis of data obtained during a prospective multicenter study on ERCP-related adverse events (Table 3), patients undergoing PS (both TPS and PP) were extracted and compared [89]. Of 3,178 patients who underwent initial ERCP, 216 patients underwent PS; 140 TPS and 76 PP were performed. There were no significant differences in primary success rates of SBC in those who underwent TPS and PP (82.9% vs. 90.8%). Eventual success rates were 90.0% vs. 90.8%, respectively. Furthermore, overall adverse events and rates of acute PEP were not significantly different between the two groups (14.3% vs. 18.4% and 11.4% vs. 11.8%, respectively).

The timing of precut sphincterotomy

Early implementation of PS has been proposed to reduce adverse events related to prolonged attempts at SBC [53,73,81]. Studies that evaluate the timing of PS during ERCP are compared in Table 4. In a meta-analysis of 6 randomized controlled trials that included 966 ERCP patients, PS using various techniques (PP, PF, and EPP) were compared to persistent attempted cannulation using standard techniques [81]. Overall biliary cannulation was similar at approximately 90% (OR 1.20; [95% CI] 0.54-2.69). A significantly lower PEP rate was seen in the early PS group, 2.5% vs. 5.3% respectively (OR 0.47; 95% CI: 0.24-0.91). The overall adverse event rates, including bleeding, pancreatitis, cholangitis, and perforation, were not significantly different (OR 0.78; [95% CI] 0.44-1.37) between the early PS group and the persistent attempt group (5.0% versus 6.3%, respectively). This suggests that in experienced hands, persistent cannulation attempts and early implementation of PS have similar cannulation rates but early PS reduces the incidence of PEP without adversely affecting the overall adverse event rate.

Table 4

Comparison of Precut Timing [31,73]

In a retrospective study, the safety and efficacy of early PP for selective biliary access was assessed [66]. The authors reviewed a cohort of 765 patients who underwent ERCP, of which 55 patients early PP for the following criteria: 1) inadvertent guidewire cannulation of PD on three occasions; 2) biliary stone impacted at papilla; 3) inability to achieve deep cannulation within 10 min. The authors excluded patients due to: 1) the inability to visualize the papilla because of anatomical distortions; 2) complete tumor occlusion of distal bile duct; 3) failure to adhere to inclusion criteria. Of patients meeting the criteria for early PP, immediate biliary cannulation was achieved in 89% of cases, and this rate was increased to 98.2% with repeat ERCP. The overall adverse event rate for the cohort of 765 patients who received ERCP with and without PP was 2.1% (16 of 765), which included: pancreatitis 1.3%, bleeding 0.7%, and perforation 0.3%. The only adverse event observed in the early PP subgroup was pancreatitis (1.8%), which was not significantly different than the standard technique group 1.3% (9 of 710 patients).

Finally, it is important to note that as for any endoscopic procedure the choice of PS technique remains highly individualized and dependent on multiple factors (patient’s anatomy, ERCP indication, endoscopist expertise). The success rate of PS improves with increasing experience and biliary cannulation is requisite for therapeutic ERCP. Based on the currently available data it is recommended to perform PS earlier during the procedure than to risk higher rates of adverse events by continued unsuccessful attempts at biliary cannulation.

Conclusions

Selective cannulation of the biliary duct remains the limiting step in therapeutic ERCP. Difficult biliary cannulation is defined as failure to achieve deep and SBC after 10 or greater attempts or greater than 10 min after first attempt using standard cannulation techniques. There are several resources which may be used to aid successful biliary cannulation including guidewire-assisted biliary cannulation using a sphincterotome, PD guidewire cannulation followed by attempted biliary guidewire cannulation, placement of a PD stent followed by attempted biliary guidewire cannulation and precut biliary sphincterotomy, also known as access sphincterotomy. Placement of a PD stent or use of a guidewire reduces the rate of PEP when attempting SBC. PS increases cannulation success rates, but may be associated with an increased rate of adverse events even when performed by endoscopists with significant experience. Endoscopists who are inexperienced in PS should consider using alternate techniques depending on the urgency and indication for the procedure. For the experienced endoscopist, it appears that early PS (especially with placement of a prophylactic PD stent) reduces the risk of adverse events as compared to persisting with standard techniques to achieve SBC.