Technical Reports of Endoscopic Retrograde Cholangiopancreatography Guidewires on the Basis of Physical Properties

Structural factors influencing the clinical performance of 0.025-inch guidewires for pancreatobiliary endoscopy: An experimental study

Background and study aims To develop a pancreatobiliary endoscopic guidewire with good clinical performance, an understanding of its structure is necessary. This study aimed to investigate the structural factors influencing the clinical performance of pancreatobiliary endoscopic guidewires. Methods Eight types of 0.025-inch guidewires were evaluated. The following structural properties were measured: tip length, tip deflection height, tip weight (TW), ratio of tip core weight to TW, shaft coating type (flat or uneven), outer diameter, and core wire diameter (CWD). Four performance tests were conducted to evaluate shaft stiffness as bending force (BF), shaft lubricity as friction force (FF), torque response as torque response rate (TRR), and seeking ability as total insertion success (TIS) in a technical test using a 3D bile duct model. The correlation coefficients of each variable were analyzed. Results The BF and CWDs were strongly correlated, as well as the FF and CWDs and BF. Among the guidewires with similar CWDs, the guidewires with uneven coating had significantly lower FF than those with flat coating. The TRR was strongly correlated with the CWDs; furthermore, guidewires with lower FF had better TRR. TIS was strongly correlated with the TRR, TWs, and ratio of the tip core weight to TW. Conclusions CWD affects shaft stiffness; CWD and coating type affect shaft lubricity and torque response. Because TRR and TW are correlated with seeking ability, an appropriate combination of core wire thickness, TW, and coating design is required to develop a guidewire with good seeking ability.

Comparison of guidewires for successful cannulation of biliary stenosis and targeting of biliary branches in ERCP

Background and study aims Guidewires play a crucial role in endoscopic retrograde cholangiopancreatography. The ability to pass through stenosis, and the ability to seek the desired biliary branch are particularly important. In this study, we aimed to compare these specific abilities in various guidewires by using a bile duct model. Patients and methods Seven 0.025-inch angle-type guidewires (VisiGlide2, Fielder 25, EndoSelector, NaviPro, Jagwire Plus, RevoWave DualMaster, and J-WIRE prologue ST) were evaluated. To compare these, a bile duct silicone model was prepared. The time from the entry of the guidewire into the common bile duct with the stenosis to the emergence of the guidewire from the common bile duct after reaching two target intrahepatic bile duct branches was measured. Results VisiGlide 2 and Fielder 25 were the fastest guidewires, whereas Jagwire Plus was the slowest. Conclusions In this study, a guidewire with a tip deflection height of approximately 9 mm and a hydrophilic coating length of 7 to 8 cm achieved the fastest completion time for the course. In clinical practice, it is important to consider the performance required in various scenarios and to select the most appropriate guidewire. The results of this model test, which focused on the time required to complete the course around the model, can serve as a foundation for guidewire selection. This method holds potential utility in future guidewire development.

Comparison of Two Types of Guidewires for Malignant Hilar Biliary Obstruction by Endoscopic Retrograde Cholangiopancreatography: A Randomized Controlled Trial

Background: There is insufficient information regarding the optimal guidewire for managing malignant hilar biliary obstruction (MHBO). Therefore, a newly designed 0.025-inch guidewire was compared with the conventional 0.035-inch guidewire for selective cannulation of both intrahepatic ducts (IHDs) in patients with MHBO. Methods: Patients were randomly enrolled into the curved type newly designed 0.025-inch guidewire group (0.025 group) or the curved type conventional 0.035-inch guidewire group (0.035 group). The primary outcome was the selective cannulation rate of IHD. If the assigned guidewire failed to pass the stricture within 5 min, the crossover guidewire was selected. If the crossover guidewire failed to cross the stricture within the next 5 min, it was judged as a failed selective cannulation of both IHDs. Results: A total of 90 patients were enrolled (0.025 group, n = 47; 0.035 group, n = 43). There was no significant difference in baseline characteristics between the groups regarding sex, age, BMI, obstruction level, and clinical presentation. Four patients (8.5%) in the 0.025 group the cannulation of the IHD failed and the conventional 0.035-inch guidewire was substituted in a second attempt; the 0.035-inch guidewire failed to cross the stricture in all four patients. In the 0.035 group, eleven patients (25.6%) failed to achieve selective cannulation of IHD, and the 0.025-inch guidewire was substituted; the newly designed 0.025-inch guidewire crossed the stricture in ten of these (10/11, 90.9%). The selective cannulation rate of IHD was significantly higher in the 0.025 group (95.1% vs. 85.5%, p = 0.043). Conclusions: The 0.025 group exhibited a higher success rate for selective cannulation of both IHDs in MHBO than did the 0.035 group.

Efficacy of a Newly Developed Guidewire for Selective Biliary Cannulation: A Multicenter Randomized Controlled Trial

BACKGROUND AND AIMS

Various guidewires are used for biliary cannulation, and each one has its own characteristics affecting its effectiveness. This study aimed to measure the basic properties and evaluate the effectiveness of a newly developed 0.025-inch guidewire for selective biliary cannulation.

METHODS

A total of 190 patients at five referral hospitals were randomly allocated to undergo selective biliary cannulation using the newly developed guidewire (NGW group, n = 95) or a conventional guidewire (CGW group, n = 95). The primary outcome was the selective biliary cannulation rate in naïve papillae. The secondary outcome was to measure the NGW basic properties, compare them with those of the CGW, and analyze the importance of basic property differences.

RESULTS

There were no significant differences between the groups in the baseline characteristics. The primary outcome (75.8% vs. 84.2%, p = 0.102) and adverse event rate (6.3% vs. 4.2%, p = 0.374) were similar in both groups. However, compared with the CGW group, the NGW group showed a higher number of ampulla contacts (2.58 vs. 2.02, p = 0.011) and longer cannulation time (216.5 vs. 135.1 s, p = 0.016). Furthermore, the NGW group had higher maximum friction (34.6 ± 1.34 vs. 30.2 ± 4.09), lower stiffness, and better elastic resiliency. In the multivariate analysis, a curved-tip GW (OR = 0.26, 95% CI 0.11-0.62, p = 0.002) and normal papillary shape (OR = 0.39, 95% CI 0.17-0.86, p = 0.021) were contributing factors for successful selective biliary cannulation.

CONCLUSIONS

The NGW group had high friction and low stiffness, characteristics affecting biliary cannulation. Clinically, the NGW group had similar success and adverse event rates as the CGW, but they showed a higher number of ampulla contacts and longer cannulation time.

Efficacy of a newly developed guidewire for selective biliary access

A clinical efficacy study of 0.025-inch guidewires (GWs) according to mechanical property analysis has not been reported yet. This study was designed to evaluate the clinical efficacy of a newly developed 0.025-inch GW for biliary access according to the basic mechanical property. Commercially available 0.025-inch GWs were in vitro tested based on parameters of mechanical property. Patients with naïve papilla requiring diagnostic or therapeutic ERCP were randomly assigned to an experimental 0.025-inch newly developed GW or a control 0.025-inch GW group. Technical success rate of wire-guided cannulation (WGC), difficult biliary cannulation (DBC), and adverse event rates were measured in this multicenter randomized trial. The technical success rate of primary WGC was 79.1% (151 of 191) in the experimental group and 70.8% (131 of 185) in the control group (95% two-sided confidence interval: 8.25%; p < 0.001; for a noninferiority margin of 15%). The technical success rate including cross-over to each other was also non-inferior. However, the chi-square test showed a statistical difference (81.7% vs. 68.1%; p = 0.002). Median biliary cannulation time was shorter in the experimental group (53 s vs. 77 s; p = 0.047). The rate of DBC was more frequent in the control group (34.6% vs. 50.3% p = 0.002). Multivariate analysis revealed that control group was one of contributing factors for DBC. Overall rate of post-ERCP pancreatitis was not different (4.7% vs. 8.6%; p = 0.125). WGC using a newly developed GW with superior physical performance GW in a bench test showed similar clinical efficacy and the rate of DBC was significantly lower in experimental GW.

Guidewire Impaction in the Main Pancreatic Duct in a Patient with Chronic Pancreatitis: A Case Report

The guidewire is an essential accessory in ERCP. Although rare, guidewires can cause complications, such as subcapsular hepatic hematoma, perforation, knotting, fracture, and impaction, during ERCP. This report describes a guidewire impaction during the endoscopic treatment of a patient with symptomatic chronic pancreatitis. The methods used to treat guidewire impaction are not well known. In the present case, the impacted guidewire was retrieved by inserting another guidewire and dilating the space adjacent to it. Endoscopists should check for the free movement of the guidewire before stent deployment. Additionally, it is important to ask for help from experienced senior staff to overcome any challenges during the procedure. In conclusion, endoscopists should be aware of the possibility of a guidewire impaction during ERCP.

Impact of guidewire caliber on ERCP outcomes: Systematic review and meta-analysis comparing 0.025- and 0.035-inch guidewires

Background and study aims  The impact of guidewire caliber on endoscopic retrograde pancreatography (ERCP) outcomes are not clear. Recent studies have compared two guidewires, 0.035- and 0.025-inch, in randomized controlled trials (RCTs). We performed a systematic review and meta-analysis of available RCTs to assess if different caliber would change the outcomes in ERCP. Patients and methods  A systematic search of PubMed/Medline, Embase, Cochrane, SciELO, Global Index Medicus and Web of Science was undertaken through November 23, 2021 to identify relevant RCTs comparing the two guidewires. Binary variables were compared using random effects model and DerSimonian-Laird approach. For each outcome, risk-ratio (RR), 95 % confidence interval (CI), and P values were generated. P  < 0.05 was considered significant. Results  Three RCTs with 1079 patients (556 in the 0.035-inch group and 523 in the 0.025-inch group) were included. The primary biliary cannulation was similar in both groups (RR: 1.02, CI: 0.96-1.08, P  = 0.60). The overall rates of PEP were also similar between the two groups (RR: 1.15, CI: 0.73-1.81, P  = 0.56). Other outcomes (overall cannulation rate, cholangitis, perforation, bleeding, use of adjunct techniques) were also comparable. Conclusions  The results of our analysis did not demonstrate a clear benefit of using one guidewire over other. The endoscopist should consider using the guidewire based on his technical skills and convenience.

Difficult Biliary Cannulation in Endoscopic Retrograde Cholangiopancreatography: Definitions, Risk Factors, and Implications

Over the past 50 years, endoscopic retrograde cholangiopancreatography (ERCP) has become the preferred minimally invasive method of treating a vast array of pancreatobiliary diseases. An initial sine qua non for ERCP success is selective ductal cannulation. Despite significant progress in the optimisation of ERCP methods and accessories, selective biliary cannulation using conventional techniques remains unsuccessful in approximately 15% of native papilla cases. Furthermore, difficult biliary cannulation has been associated with an increased risk of post-ERCP pancreatitis, among other adverse events. Here, in the first of a two-part series, the authors provide a primer on standard biliary cannulation techniques and discuss the definition, risk factors, and implications of difficult biliary cannulation. The second part of the series will provide an overview of the existing advanced techniques used in cases of difficult biliary cannulation as well as the approach to their selection.

Technical Review of Developments in Endoscopic Ultrasound-Guided Hepaticogastrostomy

Endoscopic ultrasound-guided biliary drainage has been developed as an alternative method for biliary drainage. EUS-guided hepaticogastrostomy (EUS-HGS) can be attempted via the trans-gastric route. These procedures are technically complex for two reasons. First, puncture of the intrahepatic bile duct via the trans-gastric route can be more difficult than that by other approaches because of the small diameter of the target site, and guidewire insertion or manipulation is challenging during EUS-HGS. Second, critical adverse events, such as stent migration into the abdominal cavity, could occur because of the greater mobility of the stomach compared to the duodenum. Therefore, endoscopists should be cautious when performing EUS-HGS. An advantage of EUS-HGS is that it can be performed in patients with complications such as duodenal bulb obstruction or surgically altered anatomy. Recent advances in technique and improvements in devices and stents for EUS-HGS have shown promise for improving the technical success rate of EUS-HGS and reducing the rate of adverse events. However, endoscopists should remain aware of the possibility of critical adverse events such as stent migration.

Experimental study of loop shape using 0.025-inch ERCP guidewires (with videos)

Background and study aims  Duct penetration by the guidewire sometimes occurs during endoscopic retrograde cholangiography, which might lead to adverse events such as acute pancreatitis. To prevent duct penetration, making a loop shape with the guidewire might provide a useful technique. The aim of this experimental study was thus to evaluate which types of guidewire can most easily form a loop shape. Methods  This experimental study evaluated six guidewires (0.025-inch, angle type): MICHISUJI; VisiGlide 2; Jagwire; Pathcorse; RevoWave-α UltraHard 2; and M-through. Flexibility of the tip, shaft stiffness, and the ability to form a loop were evaluated for each type in an ex vivo model. Deformation behavior was also recorded on video, and factors suitable for making a loop shape in each guidewire were evaluated. Results  Flexibility and stiffness of each guidewire differed significantly. During an experimental study regrading deformation behavior before forming a loop shape, maximum load was lower for MICHISUJI (6.8 g) than for other guidewires (Jagwire [11.3 g], M-through [12.9 g], VisiGlide 2 [12.9 g], Revowave [21 g], and Pathcorse [25.4 g]). Mean time required to achieve a loop shape was as follows: MICHISUJI, 6.2 seconds; M-through, 8.7 seconds; VisiGlide 2, 11.0 seconds; and Revowave, 7.1 seconds. Conclusion  In conclusion, characteristics of flexibility and stiffness among guidewires were significantly different in the ex-vivo study. In the experimental study regrading deformation behavior until achieving a loop shape, maximum load also differed. To evaluate whether guidewires easily form a loop shape, clinical study is needed.

Clinical Evaluation of a Newly Developed Guidewire for Pancreatobiliary Endoscopy

Background: The guidewire (GW) plays an important role in pancreatobiliary endoscopy. GW quality is a critical factor in the effectiveness and efficiency of pancreatobiliary endoscopy. In this study, we evaluate a new 0.025 inch multipurpose endoscopic GW: the M-Through. Methods: Our study was a multicenter retrospective analysis. We enrolled patients who underwent endoscopic procedures using the M-Through between May 2018 and April 2020. Patients receiving the following endoscopic treatments were enrolled: common bile duct (CBD) stone extraction, endoscopic drainage for distal and hilar malignant biliary obstruction (MBO), and endoscopic drainage for acute cholecystitis. For each procedure, we examined the rate of success without GW exchange. Results: A total of 170 patients (80 with CBD stones, 60 with MBO, and 30 with cholecystitis) were enrolled. The rate of completion without GW exchange was 100% for CBD stone extraction, 83.3% for endoscopic drainage for MBO, and 43.3% for endoscopic drainage for cholecystitis. In unsuccessful cholecystitis cases with the original GW manipulator, 1 of 8 cases succeeded in the manipulator exchange. Including 6 cases who changed GW after the manipulator exchange, 11 of 16 cases succeeded in changing GW. There was significant difference in the success rate between the manipulator exchange and GW exchange (p = 0.03). The insertion of devices and stent placement after biliary cannulation (regardless of type) were almost completed with M-through. We observed no intraoperative GW-related adverse events such as perforation and bleeding due to manipulation. Conclusion: The 0.025 inch M-Through can be used for endoscopic retrograde cholangiopancreatography-related procedures efficiently and safely. Our study found high rates of success without GW exchange in all procedures except for endoscopic drainage for cholecystitis. This GW is considered (1) excellent for supportability of device insertion to remove CBD stones; (2) good for seeking the biliary malignant stricture but sometimes need the help of a hydrophilic GW; (3) suboptimal for gallbladder drainage that require a high level of seeking ability.

Production of ERCP training model using a 3D printing technique (with video)

BACKGROUND

ERCP training models are very different in terms of anatomical differences, ethical issues, storage problems, realistic tactile sensation, durability and portability. There is no easy way to select an optimized model for ERCP training. If the ERCP training model could be made as a soft silicone model using 3D printing technique, it would have numerous advantages over the models presented so far. The purpose of this study was to develop an optimized ERCP training model using a 3D printing technique and to try to find ways for implementing various practical techniques.

METHODS

All organ parts of this model were fabricated using silicone molding techniques with 3D printing. Especially, various anatomy of the ampulla of Vater and common bile duct (CBD) were creatively designed for different diagnostic and therapeutic procedures. In order to manufacture each of the designed organ parts with silicone, a negative part had to be newly designed to produce the molder. The negative molders were 3D printed and then injection molding was applied to obtain organ parts in silicone material. The eight different types of ampulla and CBD were repeatedly utilized and replaced to the main system as a module-type.

RESULTS

ERCP training silicone model using 3D technique was semi-permanently used to repeat various ERCP procedures. All ERCP procedures using this model could be observed by real-time fluoroscopic examination as well as endoscopic examination simultaneously. Using different ampulla and CBD modules, basic biliary cannulation, difficult cannulation, stone extraction, mechanical lithotripsy, metal stent insertion, plastic stent insertion, and balloon dilation were successfully and repeatedly achieved. Endoscopic sphincterotomy was also performed on a specialized ampulla using a Vienna sausage. After repeat procedures and trainings, all parts of organs including the ampulla and CBD modules were not markedly damaged or deformed.

CONCLUSIONS

We made a specialized ERCP training silicon model with 3D printing technique. This model is durable, relatively cheap and easy to make, and thus allows the users to perform various specialized ERCP techniques, which increases its chances of being a good ERCP training model.