INTRODUCTION
Despite advances in endoscopy and accessories, selective bile duct or pancreatic duct cannulation remains a high initial hurdle in endoscopic retrograde cholangiopancreatography (ERCP).1-3 The selection of intrahepatic bile ducts and guidewire passage through stenosed afferent limbs can also present difficulties during ERCP, particularly in surgically altered anatomies.
Repeated cannulation attempts increase the risk for post-ERCP pancreatitis.4,5 Various techniques, including the double guidewire technique, precut sphincterotomy or fistulotomy, and endoscopic ultrasound (EUS)-guided rendezvous techniques, have been proposed to reduce this risk and to improve cannulation success, with some favorable outcomes.6-8 European and Japanese guidelines also suggest precut techniques as an option for difficult cannulations.9,10 Even so, precutting is difficult even in expert hands, despite its potential to enhance cannulation success and reduce post-ERCP pancreatitis.11,12 Consequently, several studies have evaluated the usefulness of cannulas with manipulable tips to facilitate cannulation.13-19
Previous studies on sphincterotomes and steerable catheters have shown improved cannulation rates over conventional ERCP catheters.13-16 Even so, studies on rotatable sphincterotomes are limited.17-19 Therefore, this study was conducted to evaluate the use of TRUEtome (Boston Scientific), a rotatable sphincterotome, at a cancer institute in Japan in various settings including selective bile and pancreatic duct cannulations in patients with normal and surgically altered anatomies.
METHODS
Patients
Records for all cases in which TRUEtome was used during ERCP at our institution between October 1, 2014, and December 31, 2021, were extracted from a prospectively maintained database and reviewed retrospectively. The inclusion criteria included cases in which TRUEtome was used for selective bile duct cannulation, selective pancreatic duct cannulation, intrahepatic bile duct selection, and passage through jejunal strictures in afferent loop syndrome. The exclusion criteria included cases in which TRUEtome was strictly used for sphincterotomy and cases in which TRUEtome was used as the first cannulation device.
Rotatable sphincterotome
TRUEtome is a cannulating sphincterotome designed to allow cannulation and subsequent sphincterotomy with a single device (Fig. 1).20 The lumen of the guidewire is centered, facilitating contrast-guided and wire-guided cannulation. By rotating the handle, the assistant can rotate the sphincterotome 360° in either direction. The handle clicks into place and maintains its angle when the handle is let go. Furthermore, the tip may be bowed upwards to an extremely sharp angle to enable bile duct cannulation from a shallow scope position.
The sphincterotome has a tip length of 5 mm. Three tip diameters (3.9 Fr, 4.4 Fr, and 4.9 Fr), and two cut wire lengths (20 mm and 30 mm) are commercially available. A 3.9 Fr tip size TRUEtome with a 20-mm cut wire was utilized in all cases in this study.
Endoscopic procedures
Expert endoscopists with more than five years of experience in therapeutic endoscopy or trainees under direct supervision performed the procedures. ERCPs in patients without surgically altered anatomies were performed using side-viewing duodenoscopes (JF-260V, TJF-260V, or TJF-Q290V; Olympus Corporation). ERCPs in patients with surgically altered anatomies (Fig. 2) were performed using single-balloon enteroscopes (SBE) (SIF-H290S or SIF-Q260; Olympus Corporation).
An ERCP catheter (MTW Endoskopie Manufaktur) and a Visiglide 2 0.025-inch angled guidewire (Olympus Corporation) were used as the first ERCP catheter and guidewire, respectively. Although the precise timing for switching to TRUEtome was based on the endoscopist's discretion, TRUEtome was solely used in difficult cannulations defined by the European Society of Gastrointestinal Endoscopy as follows: >5 contacts with the papilla, >5 minutes to cannulation, or >1 unintended pancreatic duct cannulation.9 While indications for using TRUEtome were mainly determined by procedural reports, one of the authors (TO) reviewed videos for each procedure and determined the attributes of difficult cannulations.
Post-procedural follow-up
Vital signs and laboratory markers, including serum amylase levels, were measured to identify adverse events related to the procedure. Subsequent ERCP procedures were checked for repeated TRUEtome use. Medical chart reviews were conducted to identify subsequent interventions in cases of failed ERCP. Follow-up data were reviewed up to February 28, 2022.
Statistical analysis
Categorical variables are represented as absolute numbers and percentages, while continuous variables are represented as medians with interquartile ranges. Denominators of ratios were adjusted for missing data. Statistical analyses were conducted using Pearson’s chi-square test or Fisher exact test for categorical variables, while Mann-Whitney U-tests were used for continuous variables. p-values were two-sided, and values <0.05 were considered statistically significant. All statistical analyses were conducted using IBM SPSS Statistics ver. 28.0 (IBM Corp.).
Ethical considerations
This study was approved by the Institutional Review Board of the Cancer Institute Hospital of Japanese Foundation for Cancer Research (2021-GB-118). The requirement for patient consent for inclusion in the study was waived due to the study’s retrospective nature. The study was published on the hospital website, and patients could opt out of the study without impacting their care.
RESULTS
Patient characteristics
A total of 5,261 ERCP procedures were performed during the study period. Excluding procedures with unavailable details, ERCP procedures were performed in 4,029 patients with unaltered anatomies, of which 1,101 cases (27.3%) had naïve ampullae. SBE-ERCP procedures were performed in 802 patients with surgically altered anatomies, of which 149 (18.6 %) cases had naïve ampullae. TRUEtome was used in 149 procedures, which included 110 cannulations (2.1% of all ERCP procedures). Fifteen cases in which TRUEtome was used as a rescue device in multiple sessions and seven cases in which TRUEtome was used as the first cannulation device were excluded. Therefore, 88 patients in whom TRUEtome was used to assist with guidewire manipulation as a rescue device during ERCP were finally included in this study.
The median age of the 88 patients was 71 years, with 56 (63.6%) patients being males (Table 1). Fifty-one patients underwent ERCP with a duodenoscope for pancreatic (52.9%) or biliary (27.5%) malignancies. Thirty-seven patients underwent SBE-ERCP and had surgical histories for gastric (43.2%) or pancreatic (35.1%) malignancies. TRUEtome was used for biliary and pancreatic duct cannulation (84.1%), intrahepatic bile duct selection (12.5%), and strictures of the afferent limb (3.4%).
Endoscopic procedures
Forty-one patients (80.4%) in the duodenoscope group had naïve papillae versus 14 (37.8%) in the SBE group (p<0.001) (Table 2). The total median cannulation time (including attempts with TRUEtome) was 25 minutes, while the median time for successful cannulation after switching to TRUEtome was 5.5 minutes.
The double guidewire and precut techniques were used more often in the duodenoscope group since more than half of the patients in the SBE group had hepaticojejunal anastomoses. There were no significant differences in the number of attempts or time required for cannulation between the two groups. Cannulation success rates were also similar (86.3% vs. 75.7%, p=0.213) between the groups. The median cannulation time with TRUEtome was shorter in the SBE group, but the difference was not significant (11 vs. 4 minutes, p=0.235).
Reasons for difficult cannulations or guidewire manipulations are summarized in Table 3. Difficulties arising from steep cannulation angles and repeated pancreatic duct cannulations (when attempting bile duct cannulation) had higher incidences of TRUEtome use in the duodenoscope group compared to the SBE group. Difficulties observed in SBE procedures stemmed from the cannula's direction (o’clock position), complete or extreme benign (postsurgical or post-procedural) strictures, and intrahepatic bile duct selections. Other reasons for difficult cannulation were poor scope position (duodenoscope/SBE groups 10/5), difficulty in facing the ampulla or anastomosis (5/6), floppy/hard/small ampulla (6/0), tumor invasion or ulcer at the ampulla (5/0), afferent loop syndrome (0/3), mucosal injection/swollen ampulla due to attempted cannulation (2/0), duodenal stent obstructing the ampulla (1/0), repeated bile duct cannulation (when attempting pancreatic duct cannulation; 1/0), and use of forward-viewing scope in normal anatomy due to duodenal stricture (1/0).
Adverse events and subsequent procedures
Post-procedural amylase was elevated in 38.6% of cases and which tended to be higher in the duodenoscope group compared to the SBE group (47.1% vs. 27.0%, p=0.057). There were no significant differences in adverse events, which included four cases of pancreatitis (two mild, one moderate, and one severe case based on the American Society of Gastrointestinal Endoscopy lexicon for endoscopic adverse events) and eight cases of fever that resolved with conservative treatment, between the two groups.21
TRUEtome was reused for cannulation in repeated interventions in six of the 72 successful cases (8.3%).
ERCP failure
Despite TRUEtome use, cannulation or intrahepatic bile duct selection was not achieved in seven cases in the duodenoscope group and nine in the SBE group. There were no significant differences in baseline characteristics, including surgical reconstruction, between successful and failed cases (Table 4). Failures were associated with difficulty in facing the ampulla or anastomosis (6.9% vs. 37.5%, p=0.004) and in complete or extreme postsurgical (hepaticojejunal anastomotic) or post-procedural strictures (2.8% vs. 31.3%, p=0.002). Mild hyperamylasemia, observed in three cases, was the only adverse event reported in the failed cases.
Of the 16 failed cases, six were treated successfully in a second ERCP session (cannulation was achieved using TRUEtome in two cases). Four were managed conservatively, including one in which EUS-guided pancreatic duct drainage was attempted but was unsuccessful. Three were treated using the rendezvous technique with percutaneous transhepatic biliary duct puncture. The three remaining cases were treated with EUS-guided hepaticogastrostomy, EUS-guided choledochoduodenostomy, and retrograde EUS-guided hepaticojejunostomy.22
DISCUSSION
The use of TRUEtome in difficult ERCP cases was investigated in this study. We found that cannulation or guidewire insertion into the desired duct could be achieved with TRUEtome in 81.8% of failed cases with other ERCP devices. The cannulating sphincterotome was useful in both unaltered and surgically altered anatomies, not only in bile duct and pancreatic duct cannulations, but also in intrahepatic bile duct selection and the passage of guidewires through strictures in the afferent limb in postsurgical afferent loop syndrome. Reasons for difficult cannulation or guidewire manipulations and for ERCP failures despite TRUEtome use differed between unaltered and surgically altered anatomies.
There are two large studies on cannulation with rotatable sphincterotomes in the existing literature.17,18 Kurita et al.17 conducted a prospective randomized controlled trial comparing conventional and rotatable sphincterotomes for selective bile duct cannulation. This study failed to identify any significant differences in cannulation success rates or complications, although the rotatable sphincterotome was used in four patients in the conventional sphincterotome group. Zhu et al.18 conducted a retrospective study on 86 patients with a history of Billroth-II gastrectomy. This study found higher rates of cannulation within 5 minutes and a lower incidence of pancreatitis with rotatable sphincterotomes, but similar overall success rates. A case series achieved a 100% success rate for selective bile duct cannulation in six patients with surgically altered anatomies.19 The successful use of rotatable sphincterotomes has also been reported in situs inversus totalis and for guidewire manipulation in EUS-guided hepaticogastrostomies.23,24 Uneven double-lumen cannulas have also been associated with higher success rates and faster bile duct cannulation in surgically altered anatomies, although pancreatic duct cannulation is a prerequisite for this method.25
In this study, we ultimately achieved an 81.8% success rate for difficult cannulation cases with TRUEtome, with no significant difference between duodenoscopic and SBE groups. Adverse events, including four cases of pancreatitis (4.5%), were most likely due to the high number of cannulation attempts and the long time required to achieve cannulation. We believe this adverse event rate is acceptable, considering that three of the cases involved extremely difficult SBE procedures on patients with Roux-en-Y anastomoses. In addition, success was achieved with TRUEtome after precut sphincterotomy in seven cases, owing to the steep angulation achieved by the sphincterotome.
While success rates and adverse events were similar between the duodenoscope and SBE groups, the reasons for difficult cannulation differed. The leading indication for TRUEtome in the duodenoscope group was a steep cannulation angle required to cannulate the bile duct; this problem was easily overcome with TRUEtome. The second most common indication was bile duct cannulation after repeated pancreatic duct cannulation, which was supported by TRUEtome’s fine angular and directional adjustments. Shallow scope position was the third most common indication; these positions frequently led to repeated pancreatic duct cannulation but cannulation could be achieved by bowing up the sphincterotome to a steep angle. The most common indication in the SBE group was the direction of the bile duct in relation to the endoscope. Unlike ERCP in unaltered anatomies where cannulation is generally achieved in the 11 or 12 o’clock position, the guidewire must be manipulated in almost any direction depending on the position of the SBE. The rotation function of TRUEtome was extremely useful in this regard, leading to success in all cases in this subgroup.
Despite its clinical importance, few studies have been conducted on the use of sphincterotomes for intrahepatic bile duct selection. A retrospective study used a short-nosed sphincterotome to achieve successful intrahepatic bile duct selection in 15 out of 16 patients.26 Similarly, our study achieved intrahepatic bile duct selection with TRUEtome in ten out of 11 patients (88.9%). TRUEtome was used more frequently for intrahepatic bile duct selection during SBE-ERCP since shorter and larger common bile ducts facilitated the advancement of TRUEtome to the hilum. Success in intrahepatic bile duct selection using TRUEtome was also achieved in the duodenoscope group, however.
The median cannulation time of 5.5 minutes after lengthy attempts with a conventional ERCP catheter makes TRUEtome an attractive option in various settings. It is now our practice to consider the use of TRUEtome before attempting precut or EUS-guided rendezvous techniques. Even so, TRUEtome use is ineffective in some cases, including cases in which duodenal tumor invasion precludes securing enough distance between the duodenoscope and the ampulla required to curve the sphincterotome.
Key limitations of this study include its retrospective, single-arm, single-center design and its limited sample size. Another limitation is that the decision and timing for the use of TRUEtome were determined by the endoscopist rather than by predetermined criteria. The heterogeneity observed in our cohort, including cases of selective pancreatic duct cannulation, intrahepatic bile duct selection, and afferent loop syndromes, limited our ability to make generalized comparisons between the duodenoscope and SBE groups. However, this observed heterogeneity reflects real-world settings and demonstrates TRUEtome’s versatility in various problematic settings.
In conclusion, TRUEtome was useful in the cannulation of various ducts, branches, and strictures in unaltered and surgically altered anatomies. The steep angulation and rotation functions of the rotatable sphincterotome may make it a viable alternative to more difficult techniques such as precut and EUS-guided rendezvous techniques.
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