Sequential algorithm analysis to facilitate selective biliary access for difficult biliary cannulation in ERCP: a prospective clinical study

This was a prospective clinical study conducted in a tertiary referral center. A total of 711 consecutive patients with naïve papillae were enrolled from September 2010 to August 2012. Patients who satisfied the following inclusion criteria were enrolled: those with naïve papilla who underwent ERCP for biliary endotherapy, age ≥ 18 years, and agreement to participate in the study. Exclusion criteria were: age < 18 years, successful deep biliary cannulation within 5 min, surgically altered anatomy (Billroth II gastrectomy or Roux-en-Y anastomosis), an indwelling biliary stent, prior biliary or pancreatic sphincterotomy, uncontrolled coagulopathy, and refusal to agree to the study protocol. All patients underwent abdominal ultrasonography, computed tomography, magnetic resonance cholangiopancreatography or endoscopic ultrasonography prior to ERCP. The Institutional Review Board at the Soonchunhyang University Hospital approved this protocol, and all participants provided informed consent.

Difficult biliary cannulation was defined as failure to achieve selective biliary access by wire-guided cannulation despite 5 min of attempted cannulation (cannulation time > 5 min), papillary contacts > 5 times, attempted unintentional pancreatic duct cannulation ≥ 3 times, or hook-nose-shaped papilla (difficult type of cannulation) [6]. Meaningful papillary contact was defined as sustained contact for cannulation between the guidewire-preloaded papillotome and the ampulla of Vater for at least 3–5 seconds of manipulation [6, 8, 9]. The configuration of a hook-nose-shaped papilla, which is a difficult type to cannulate conventionally, was based on a previous report; papilla shapes were classified into one of four categories: the non-prominent type, wherein the major papilla lacked a marked oral protrusion; the prominent type, with marked oral protrusion of the major papilla; the bulging or hook-nose type, with marked swelling of the oral protrusion; and the distorted type, with an unclassified unusual shape and position [6]. The frequency of papillary contact or unintentional pancreatic duct cannulation was measured by skilled assistant nurses. The procedural time for cannulation was calculated as the interval between the duodenal intubation and initiation of precut or other procedures, whereas the precut procedure time was the interval between initiation of precut and either successful biliary cannulation or termination of the procedure on the video monitoring system. The serum amylase level was measured before ERCP and 24 h after. All complications were classified and graded according to consensus guidelines [10]. PEP was defined as follows; new or worsened abdominal pain with elevation of serum amylase at least three times above the upper normal limits for 24 hours after a procedure that requires at least 2–3 days (mild), 4–10 days (moderate), and more than 10 days (severe) of hospitalization. Hemorrhage was considered clinically significant only if there was clinical (not just endoscopic) evidence of bleeding, such as melena or hematemesis, with an associated decrease of at least 2 g per deciliter in the hemoglobin concentration, or the need for a blood transfusion. Perforation included retroperitoneal or bowel wall perforation documented by any radiographic images.

All patients underwent ERCP using a standard duodenoscope (TJF 240 or 260 V; Olympus Optical Co., Ltd., Tokyo, Japan) following an overnight fast. Patients were placed in the prone or lateral position after being sedated with intravenous midazolam (0.05 mg/kg), fentanyl (25–50 μg), and/or propofol (0.5 mg/kg). Prophylactic antibiotics and analgesics were permitted.

Selective cannulation of the common bile duct (CBD) was attempted initially using a standard wire-guided cannulation technique. The papillotome was oriented from the 11 to the 12 o’clock positions on the ampulla of Vater and bowed to align it correctly with the bile duct axis. Following minimal insertion of a pull-type papillotome into the papilla, a 0.035-inch guidewire (Hydra Jagwire; Boston Scientific or Tracer Metro; Cook Medical, Winston Salem, NC, USA) was advanced carefully through the CBD under fluoroscopy until it was observed to enter the bile duct. Contrast injection was not attempted routinely before selective placement of the guidewire in the CBD.

When wire-guided cannulation failed based on the DBC criteria, including cannulation failure within 5 min of attempted cannulation (cannulation time > 5 min), papillary contact > 5 times, or a hook-nose-shaped papilla, a precut fistulotomy (infundibulotomy) using a needle-knife (Microtome; Boston Scientific, Microvasive, Marlboro, MA, USA) was performed as an rescue method. EPF was initiated over the bulging portion of the papillary roof, extended upwards or downwards, and stopped short of the papillary orifice to avoid the risk of duodenal perforation or injury to the pancreatic sphincter. The bile duct was probed using a guidewire-preloaded needle-knife after making an incision into the intraduodenal segment of the CBD. A precut fistulotomy was performed with a blended electrosurgical current (UES-30 generator; Olympus).

If unintentional pancreatic duct cannulation occurred more than 3 times during the initial attempts at wire-guided cannulation, DGC was attempted. We used a papillotome pre-inserted with a 0.035-inch guidewire to facilitate biliary cannulation for DGC. The first guidewire was inserted into the pancreatic duct to at least half of the presumed total length of the pancreatic duct under fluoroscopy. No contrast was injected into the pancreatic duct for the purpose of diagnosis. The papillotome was reinserted along the first guidewire after being reloaded with the second guidewire. The direction of the CBD was towards the 10–11 o’clock position. After successful biliary cannulation was achieved, a biliary sphincterotomy over the guidewire was performed and the guidewire was removed from the pancreatic duct without pancreatic stenting.

If the sum of papillary contact and unintentional pancreatic duct cannulation exceeded 5 times despite ongoing DGC, PPS was performed. After placement of the pancreatic stent (single 6 or 8 cm-long 5 F pigtail-type, Zimmon; Cook Endoscopy), a cut was made from the orifice of the ampulla of Vater adjacent to the pancreatic stent. Following this, the selective wire-guided cannula method was used for selective biliary access in the same manner. If the pancreatic stent had not migrated spontaneously within 1 week, it was removed endoscopically.

All endoscopic procedures were recorded with a video recording system, and the outcomes were analyzed. All ERCP procedures were performed by a single experienced endoscopist (L.T.H., a workload of 400 ERCPs annually with experience of more than 150 cases of precut). Guidewire manipulation and other endoscopic procedures such as cannulation attempts and time were controlled and measured by skilled assistants with at least 2 years of training (P.S.J., L.J.H., and K.A.R.).

Sequential EPF, DGC, and PPS were performed according to the algorithm (Figure 1). The initial cannulation was attempted using the wire-guided cannulation method. Then, EPF was performed first if primary wire-guided cannulation failed based on the following criteria: papilla contact > 5, cannulation time > 5 min, or a hook-nose-shaped papilla. Next, DGC was attempted if unintentional pancreatic duct cannulation occurred more than 3 times. Third, PPS was attempted if the sum of papilla contact and unintentional pancreatic duct cannulation exceeded five times during the trial of DGC. If selective biliary cannulation failed even after the above procedures, we performed a second ERCP after 2 days or subsequent percutaneous transhepatic biliary drainage (PTBD) depending on the patient’s condition, such as sepsis or severe cholangitis.

The mean, standard deviation (SD), and range were used to summarize the data for continuous variables, and percentages were used for categorical variables. Fisher’s exact test or χ ²-test was used to identify associations between categorical variables. Statistical significance between the groups was tested by one-way analysis of variance. A P-value < 0.05 was considered to indicate statistical significance. The statistical analysis was carried out using SPSS ver. 14.0 (SPSS, Chicago, IL, USA).

The mean procedural time (SD) for successful biliary access was 559.7 (403.6) seconds in the enrolled patients with DBC. The selective successful biliary cannulation time was shorter in the DGC group than in the other groups (314.8 ± 65.2 seconds in DGC, 559.4 ± 412.8 seconds in EPF, and 706.0 ± 469.4 seconds in PPS; P < 0.05). No significant difference in successful cannulation time between EPF and PPS was found (P = 0.127) (Table 2). The success rate of selective biliary cannulation was 90% (126/140) for the first attempt (EPF, 88.7%; DGC, 47.8%; PPS, 83.3%). The first attempted successful DGC rate was relatively low (47.8%; 33/69), but involved a relatively short cannulation time as difficult DGC was early switched to the PPS method, according to the algorithm in difficult DGC. Second attempts performed 2 days later were successful in 10 (83.3%) of 12 patients. The overall successful cannulation rate was 97.1% (136/140; EPF, 94.4%; DGC, 47.8%; PPS, 100%; P < 0.001). Technical failure occurred in only 2.8% (4/140), all of which were in the EPF group (Table 3). These four patients had severe strictures of the bile duct due to metastatic malignancy (n = 1), ampulla of Vater cancer (n = 1), or pancreas head cancer (n = 2). A second attempt was successful in four of six in the EPF group. Two patients underwent PTBD due to cholangitis and sepsis after the first attempt, and the other two patients underwent PTBD following failure of the second attempt.

Post-ERCP pancreatitis developed in 14 patients (10%), and minor bleeding occurred in four (2.8%). PEP was mild except one moderate case of pancreatitis, and no significant differences among the three groups were found (P = 0.870). There was no significant difference in the PEP rate between the DBC and remaining conventional group, which was collected during the same study period (10% vs. 6.3%, 36/571; P = 0.125). In the multivariate analysis, female gender was a risk factor for PEP (odds ratio, 4.16; 95% confidence interval, 1.108–15.645, P = 0.035) (Table 4). All complications including bleeding were managed conservatively without mortality.