ABSTRACT
Objectives
We aimed to compare the clinical outcomes of the bent guidewire insertion (BGI) technique and the conventional straight guidewire insertion (SGI) technique for managing recurrent malignant biliary obstruction (RMBO) after initial uncovered metallic stent (UMS) placement.
Methods
Ninety patients who underwent endoscopic intervention for RMBO after UMS placement were retrospectively included. Clinical outcomes and endoscopic retrograde cholangiopancreatography (ERCP)‐related factors were compared between the SGI and BGI groups. Univariate and multivariate logistic regression analyses were performed to identify the independent risk factors associated with difficult cannulation.
Results
There were 43 and 47 patients who underwent the SGI and BGI techniques, respectively, for intervention of RMBO. The SGI group had significantly higher rates of difficult cannulation (48.8% vs. 19.1%, p = 0.006) and guidewire insertion technique transformation (44.2% vs. 4.3%, p < 0.001). Additionally, procedure time (49.7 min ± 23.4 min vs. 34.7 min ± 20.5 min, p = 0.002) and cannulation time (5.0 min vs. 4.0 min, p = 0.005) were longer in the SGI group. Technical and clinical success rates, procedure‐related complications, and length of hospitalization were comparable between the two groups. Multivariate analysis revealed that SGI (odds ratio [OR] 4.682, 95% confidence interval [CI] 1.643–13.340, p = 0.004) and hilar biliary tract lesions (OR 3.673, 95% CI 1.236–10.915, p = 0.019) were identified as independent factors for difficult biliary cannulation.
Conclusion
BGI technique may be superior to SGI approach for re‐intervention in patients with RMBO after initial UMS placement.
Keywords: cannulation, guidewire insertion technique, malignant biliary obstruction, treatment outcome, uncovered metallic stent
The bent guidewire insertion (BGI) technique significantly reduces the rate of difficult cannulation and shortens the procedure time compared with the conventional straight guidewire insertion (SGI) technique for the intervention of recurrent malignant biliary obstruction (RMBO). BGI maintains comparable technical success and safety while markedly lowering guidewire technique transformation needs. SGI use and hilar lesions independently predict difficult cannulation, underscoring the procedural advantage of BGI.
1. Introduction
Endoscopic biliary drainage is a well‐established, minimally invasive, and preferred palliative treatment for malignant biliary obstruction (MBO) that is primarily induced by primary or secondary hepatobiliary and pancreatic malignancy [1]. The placement of metallic stents via endoscopic retrograde cholangiopancreatography (ERCP) has been extensively acknowledged as the first‐line palliative therapy of MBO and is considered to outperform plastic stents in alleviating symptoms related to cholangitis [2, 3, 4]. However, recurrent malignant biliary obstruction (RMBO) remains a major postoperative issue in clinical practice, especially following the placement of uncovered metallic stents (UMSs), which may result from tumor ingrowth [5, 6, 7]. Previous studies have demonstrated that during a median follow‐up of 6 months after UMS placement, the overall incidence of RMBO ranges from 3% to 45% [8, 9, 10]. Consequently, additional interventional measures are frequently required to relieve RMBO.
It is widely acknowledged that successful ERCP requires deep cannulation of the common bile duct (CBD) and/or main pancreatic duct [11]. Moreover, among experienced practitioners, the cannulation failure rate has generally declined to ≤ 5% [11, 12]. Guidewire‐assisted cannulation is routinely performed during ERCP; however, so far there have been no studies directly comparing the clinical outcomes of different guidewire insertion modalities. Nevertheless, during re‐intervention for RMBO after the initial stent placement, the technical success rate of cannulation and the incidence of difficult cannulation remain unclear. Following the initial placement of a UMS, repeated ERCP for subsequent stent placement may be complicated by guidewire entrapment within the stent mesh, which occurs when the guidewire penetrates the stent mesh and being trapped between the stent and the bile duct wall, thereby increasing the difficulty of cannulation, prolonging the procedure time, and potentially elevating the risk of procedure‐related complications.
Previous studies have indicated that for patients facing challenges in selective biliary cannulation, a loop‐forming guidewire can readily advance into the main pancreatic duct even when the guidewire tip is unintentionally inserted into a branch duct, thereby reducing force on the branch duct, minimizing pancreatic parenchymal injury, and lowering the risk of post‐ERCP pancreatitis without compromising technical success rates [13, 14]. Similarly, we assume that bending the distal end of the guidewire into a loop shape during insertion has the potential to prevent the guidewire from being trapped within the mesh of UMS, thus reducing the difficulty of cannulation. However, clinical outcomes of two different guidewire insertion techniques (straight insertion vs. bent insertion) on biliary cannulation have not been fully investigated.
Therefore, we conducted a retrospective, single‐center study aiming to compare the clinical outcomes of the straight guidewire insertion (SGI) and bent guidewire insertion (BGI) techniques for the intervention of RMBO. By addressing this critical technical disparity, we hope to provide evidence‐based insights to optimize procedural strategies and improve patient outcomes.
2. Patients and Methods
2.1. Patients
Between January 2019 and December 2024, consecutive patients who underwent intervention through ERCP for RMBO after initial UMS placement at the First Affiliated Hospital of Nanchang University (Nanchang, Jiangxi Province, China) were retrospectively included for analysis. MBO was defined as biliary obstruction caused by primary or secondary malignant tumors, including cholangiocarcinoma, pancreatic cancer, and metastatic malignancies, etc., based on the patient's clinical presentations, imaging and/or histopathological findings. And RMBO was defined as the recurrence of jaundice and/or cholangitis [5]; in most cases, it was considered to be associated with tumor progression, including tumor ingrowth and extrinsic compression. Among the 417 patients initially received UMS placement for MBO, 147 experienced RMBO. Of them, 57 patients were excluded because of percutaneous transhepatic biliary drainage (PTCD) (n = 28), severe cardiopulmonary function (n = 10), cleaning of sludge and debris without the need of stent placement (n = 8), and those who refused invasive intervention and requested conservative medications (n = 11). Finally, 90 patients who underwent ERCP and placement of plastic or metallic stents for RMBO were included in the analysis (Figure 1).
FIGURE 1.
Flow diagram of patient selection and grouping. BGI, bent guidewire insertion; PTCD, percutaneous transhepatic biliary drainage; RMBO, recurrent malignant biliary obstruction; SGI, straight guidewire insertion.
The study was conducted in accordance with the Declaration of Helsinki (Brazil, 2013) and was approved by the Institutional Review Board of the Ethics Committee of the First Affiliated Hospital of Nanchang University (no. IIT[2025]‐645). Written informed consent was obtained from all the patients prior to the re‐intervention procedure.
2.2. Intervention Procedures
As a tertiary referral medical center, over 2500 ERCP procedures are performed annually in our hospital. Therefore, all ERCP procedures were conducted by experienced endoscopists with more than 10 years of experiences, following standardized techniques and protocols.
All patients were under conscious sedation with intravenous midazolam and pethidine during the ERCP procedure. A side‐viewing duodenoscope (JF‐260 V or TJF‐260 V; Olympus, Tokyo, Japan) was used. A standard sphincterotome (CleverCut3V, KD‐V411M‐0725) preloaded with a 0.025‐in. straight guidewire (VisiGlide) (both from Olympus) was initially advanced into the target bile duct following successful biliary cannulation. Subsequently, cholangiography was performed to delineate the biliary anatomy, and endoscopic sphincterotomy was carried out when necessary to facilitate subsequent stent placement.
Guidewire insertion technique was determined based on routine practice and real‐time clinical judgment of the endoscopist. As illustrated in Figure 2, two different guidewire insertion techniques were applied: (a) SGI, the distal tip of the guidewire was straightly advanced into the bile duct; and (b) BGI, the distal portion of the guidewire was shaped into a loop to enhance directional control. The procedure was initiated with the endoscopist's preferred approach and, if repeated attempts were unsuccessful (generally > 5 min or after several failed passes under fluoroscopy), it was switched to the alternative technique. For analysis, patients were assigned to the SGI or BGI group according to the initially attempted guidewire insertion technique, regardless of whether a technique switch was subsequently applied or not.
FIGURE 2.
Two different guidewire insertion techniques. (A) Straight guidewire insertion. (B) Bent guidewire insertion.
For revisionary stenting, either plastic stents or covered self‐expanding metallic stents were deployed, with stent selection determined completely by the treating endoscopist according to the clinical scenario and procedural requirements.
2.3. Data Collection
Patient demographics, ERCP‐related information, and clinical outcomes were retrospectively collected from medical reports of a prospectively maintained digital ERCP data system. Baseline characteristics of the patients included age, gender, comorbidities, pre‐ERCP biochemical parameters, prior endoscopic sphincterotomy (EST) history, history of difficult cannulation, etiology of MBO, lesion location, CBD diameter, initial UMS diameter/length, duration of initial UMS patency, pattern of stent placement, endoscopist who performed the initial and repeated stenting procedures, and length of hospital stay. ERCP‐related information included guidewire insertion techniques, re‐intervention approaches, technical success rate, clinical success rate, difficult cannulation rate, technique transformation rate, cannulation time, procedure‐related complications, and procedure time.
2.4. Outcomes and Definitions
2.4.1. Primary Outcomes
The primary outcomes were the rate of difficult biliary cannulation and cannulation time. Difficult cannulation was defined when meeting at least one of the following conditions: (a) more than five contact attempts with the papilla; (b) cannulation attempts for over 5 min after the papilla was visualized; and (c) more than one unintended cannulation or opacification of the pancreatic duct.
2.4.2. Secondary Outcomes
The secondary outcomes included the technical success rate, clinical success rate, technique transformation rate, procedure‐related complications, and procedure time. Technical success was defined as successful stent placement at the targeted location. Clinical success was defined based on the biochemical response to the re‐intervention measure, including: (a) a reduction of at least 50% in serum total bilirubin (TBIL) within 1 week after the procedure; or (b) a reduction of at least 75% in serum TBIL within 4 weeks, consistent with previously established criteria [15]. Technique transformation was defined as switching from the initially preferred guidewire insertion approach to the alternative technique when repeated attempts failed to achieve successful cannulation (generally after > 5 min or several unsuccessful passes under fluoroscopy). All procedure‐related complications were systematically categorized and graded according to standardized consensus guidelines [16].
2.4.3. Other Definitions
Stent dysfunction was broadly defined as recurrence of symptoms associated with biliary obstruction, including jaundice/cholangitis, which resulted from mechanical obstruction related to tumor progression, intraluminal debris accumulation, and/or granulation tissue proliferation. The time interval between the initial UMS placement and re‐intervention was regarded as the duration of metallic stent patency. Re‐intervention was defined as any additional endoscopic biliary drainage procedure performed following technical and clinical success with plastic or metallic stenting.
2.4.4. Statistical Analysis
All the statistical analyses were performed using R software version 4.3.1 (R Foundation, Vienna, Austria). Normality of continuous variables was assessed using the Shapiro–Wilk test. Continuous variables with normal distribution were expressed as mean ± standard deviation, whereas non‐normally distributed continuous variables were expressed as median and interquartile range (IQR). Differences in normally distributed continuous variables between groups were compared using the Student's t‐test; while for those in variables with skewed distribution, intergroup comparisons were conducted using the Mann–Whitney U‐test. Categorical variables were expressed as numbers and percentages, and were analyzed with the Chi‐square test or the Fisher exact test, when appropriate. Univariate and multivariate logistic regression analyses were employed to analyze the factors affecting difficult biliary cannulation. Variables with a p value of < 0.10 in the univariate analysis were further introduced into the multivariate analysis. The results were presented as odds ratio (OR) and 95% confidence interval (CI). A two‐sided p < 0.05 was considered as statistically significant.
3. Results
3.1. Characteristics of the Patients
Altogether 90 patients who required re‐intervention due to RMBO after initial UMS placement were included for analysis. The characteristics of the patients, including baseline demographic data, clinical manifestations, and ERCP‐related outcomes based on the guidewire insertion techniques, are presented in Table 1. There were 43 patients, including 28 men and 15 women, at a mean age of (70.2 ± 11.0) years in the SGI group, while the BGI group consisted of 47 patients (26 men and 21 women) at a mean age of (69.2 ± 10.8) years. Hypertension and diabetes mellitus were observed in 46 (51.1%) and 29 (32.2%) patients, respectively. Notably, the SGI group tended to have a longer median duration of the initial UMS patency compared with the BGI group (6.1 months vs. 5.1 months), although the difference was not statistically significant (p = 0.057). In addition, no significant differences were observed between the two groups regarding the Charlson comorbidity index, etiology of MBO, prior EST, history of difficult cannulation, lesion location, CBD diameter, initial UMS diameter/length, endoscopists for both procedures, levels of preoperative biochemical parameters, or the pattern of stent placement. Moreover, no proximal or distal stent migration occurred after the initial UMS placement.
TABLE 1.
Baseline characteristics of the patients in the straight guidewire insertion (SGI) and bent guidewire insertion (BGI) groups.
| Variables | SGI group (N = 43) | BGI group (N = 47) | p value |
|---|---|---|---|
| Age, years (mean ± SD) | 70.2 ± 11.0 | 69.2 ± 10.8 | 0.674 |
| Gender, n (male/female) | 28/15 | 26/21 | 0.464 |
| Hypertension, n (%) | 22 (51.2) | 24 (51.1) | 1.000 |
| Diabetes mellitus, n (%) | 14 (32.6) | 15 (31.9) | 1.000 |
| Charlson comorbidity index (mean ± SD) | 1.4 ± 1.2 | 1.6 ± 1.1 | 0.349 |
| Etiology of MBO, n (%) | 0.281 | ||
| Cholangiocarcinoma | 23 (53.5) | 31 (65.9) | |
| Pancreatic cancer | 11 (25.6) | 6 (12.8) | |
| Others | 9 (20.9) | 10 (21.3) | |
| Prior EST, n (%) | 35 (81.4) | 32 (68.1) | 0.229 |
| History of difficult cannulation, n (%) | 9 (20.9) | 6 (12.8) | 0.450 |
| Lesion location, n (%) | 0.430 | ||
| CBD | 30 (69.8) | 28 (59.6) | |
| Hilar biliary tract | 13 (30.2) | 19 (40.4) | |
| CBD diameter, mm (median [IQR]) | 12.4 (11.1–14.0) | 12.5 (11.1–14.0) | 0.891 |
| Initial metallic stent diameter, mm (median [IQR]) | 10.0 (10.0–10.0) | 10.0 (10.0–10.0) | 0.350 |
| Initial metallic stent length, mm (median [IQR]) | 70.0 (60.0–80.0) | 70.0 (60.0–80.0) | 0.688 |
| Duration of initial metallic stent patency, months (median [IQR]) | 6.1 (4.0–10.6) | 5.1 (3.4–6.8) | 0.057 |
| Preoperative biochemical parameters | |||
| TBIL, μmol/L (median [IQR]) | 119.4 (111.3–132.4) | 119.3 (104.5–135.0) | 0.597 |
| DBIL, μmol/L (median [IQR]) | 87.3 (77.4–99.8) | 84.1 (74.9–92.0) | 0.216 |
| ALT, U/L (median [IQR]) | 86.6 (72.8–95.1) | 87.8 (79.8–103.9) | 0.436 |
| AST, U/L (median [IQR]) | 91.7 (82.2–110.9) | 96.7 (84.0–106.9) | 0.677 |
| ALP, U/L (mean ± SD) | 450.6 ± 82.9 | 433.9 ± 96.6 | 0.380 |
| γ‐GT, U/L (median [IQR]) | 374.8 (355.7–401.2) | 399.0 (361.1–440.6) | 0.055 |
| AMY, U/L (mean ± SD) | 153.7 ± 24.6 | 156.9 ± 24.9 | 0.541 |
| Pattern of stent placement, n (%) | 0.818 | ||
| Unilateral plastic stenting | 23 (53.5) | 22 (46.8) | |
| Bilateral plastic stenting | 12 (27.9) | 15 (31.9) | |
| Covered metallic stenting | 8 (18.6) | 10 (21.3) | |
| Endoscopist for both procedures, n (%) | 0.348 | ||
| Same | 9 (20.9) | 15 (31.9) | |
| Different | 34 (79.1) | 32 (68.1) |
Abbreviations: AMY, amylase; ALP, alkaline phosphatase; ALT, alanine aminotransferase; AST, aspartate transferase; CBD, common bile duct; DBIL, direct bilirubin; EST, endoscopic sphincterotomy; IQR, interquartile range; γ‐GT, γ‐glutamyl transferase; SD, standard deviation; TBIL, total bilirubin.
3.2. Clinical Outcomes and Complications
As shown in Table 2 and Figure 3, the SGI group exhibited significantly higher rates of difficult cannulation (48.8% vs. 19.1%, p = 0.006) and guidewire insertion technique transformation (44.2% vs. 4.3%, p < 0.001) compared with the BGI group. In addition, the mean procedure time (49.7 min ± 23.4 min vs. 34.7 min ± 20.5 min, p = 0.002) and the median cannulation time (5.0 min vs. 4.0 min, p = 0.005) were significantly longer in the SGI group. However, no substantial differences were observed between the two groups in terms of technical success rate (SGI vs. BGI: 90.7% vs. 93.6%, p = 0.705), clinical success rate (SGI vs. BGI: 83.7% vs. 89.4%, p = 0.634), overall procedure‐related complications (14.0% vs. 6.4%, p = 0.301), and length of hospital stay (median: 7.0 days vs. 7.0 days, p = 0.772).
TABLE 2.
Clinical outcomes of patients in the straight guidewire insertion (SGI) and bent guidewire insertion (BGI) groups.
| Variables | SGI group (N = 43) | BGI group (N = 47) | p value |
|---|---|---|---|
| Technical success, n (%) | 39 (90.7) | 44 (93.6) | 0.705 |
| Clinical success, n (%) | 36 (83.7) | 42 (89.4) | 0.634 |
| Cannulation time, min (median [IQR]) | 5.0 (4.0–9.5) | 4.0 (2.0–5.0) | 0.005 |
| Difficult cannulation, n (%) | 21 (48.8) | 9 (19.1) | 0.006 |
| Cannulation attempts > 5 | 20 (46.5) | 8 (17.0) | 0.005 |
| Cannulation time > 5 min | 19 (44.2) | 7 (14.9) | 0.005 |
| Inadvertent PD cannulation ≥ 1 | 10 (23.3) | 6 (12.8) | 0.306 |
| Guidewire insertion technique transformation, n (%) | 19 (44.2) | 2 (4.3) | < 0.001 |
| Complications, n (%) | 6 (14.0) | 3 (6.4) | 0.301 |
| Pancreatitis | 4 (9.3) | 2 (4.3) | 0.420 |
| Bleeding | 0 (0) | 1 (2.1) | 1.000 |
| Perforation | 0 (0) | 0 (0) | NA |
| Infection | 2 (4.7) | 0 (0) | 0.225 |
| Procedure time, min (mean ± SD) | 49.7 ± 23.4 | 34.7 ± 20.5 | 0.002 |
| Length of hospitalization, days (median [IQR]) | 7.0 (6.0–8.0) | 7.0 (6.0–8.0) | 0.772 |
Abbreviations: IQR, interquartile range; NA, not applicable; PD, pancreatic duct; SD, standard deviation.
FIGURE 3.
Comparison of clinical outcomes, including (A) cannulation time (presented as median and interquartile range), (B) procedure time (presented as mean ± standard deviation), (C) rate of difficult cannulation, and (D) the proportion of guidewire insertion technique transformation between the straight guidewire insertion (SGI) and bent guidewire insertion (BGI) groups.
3.3. Risk Factors Associated With Difficult Cannulation
A subgroup analysis was performed between patients with difficult and non‐difficult cannulation. The clinical characteristics and outcomes are shown in Tables S1 and S2. The proportion of cases with lesions at the hilar biliary tract was relatively high among those with difficult cannulation, although this difference was not statistically significant. Notably, significantly more patients undergoing SGI experienced difficult cannulation than those receiving BGI (70.0% vs. 30.0%, p = 0.006). In addition, the proportions of cases with guidewire insertion technique transformation (50.0% vs. 10.0%, p < 0.001) and overall procedure‐related complications (26.7% vs. 1.7%, p = 0.001) were significantly higher in the difficult cannulation group. In addition, both the median cannulation time (9.5 min vs. 3.5 min) and the mean procedure time (64.6 min ± 22.9 min vs. 30.5 min ± 11.6 min) (both p < 0.001) were significantly longer in the difficult cannulation group.
The univariate analysis revealed that the SGI technique (OR 4.030, 95% CI 1.573–10.328, p = 0.004), hilar biliary tract lesions (OR 2.213, 95% CI 0.890–5.503, p = 0.087), and Charlson comorbidity index > 1 (OR 1.492, 95% CI 0.984–2.262, p = 0.059) were associated with difficult cannulation (Table 3). Moreover, in the multivariate analysis, the SGI technique (OR 4.682, 95% CI 1.643–13.340, p = 0.004) and hilar biliary tract lesions (OR 3.673, 95% CI 1.236–10.915, p = 0.019) were identified as independent risk factors for difficult cannulation (Table 3 and Figure 4).
TABLE 3.
Univariate and multivariate analysis of risk factors for difficult cannulation.
| Variables | Univariate analysis | Multivariate analysis | ||
|---|---|---|---|---|
| OR (95% CI) | p value | OR (95% CI) | p value | |
| Age (< 70 years [ref.] vs. ≥ 70 years) | 0.816 (0.338–1.972) | 0.652 | ||
| Gender (male [ref.] vs. female) | 0.811 (0.329–1.999) | 0.648 | ||
| Hypertension (no [ref.] vs. yes) | 1.398 (0.579–3.377) | 0.457 | ||
| Diabetes mellitus (no [ref.] vs. yes) | 1.686 (0.671–4.237) | 0.266 | ||
| Charlson comorbidity index (≤ 1 [ref.] vs. > 1) | 1.492 (0.984–2.262) | 0.059 | 1.685 (0.987–2.427) | 0.065 |
| Prior EST history (no [ref.] vs. yes) | 2.143 (0.708–6.487) | 0.177 | ||
| History of difficult cannulation (no [ref.] vs. yes) | 1.000 (0.309–3.241) | 1.000 | ||
| Etiology (cholangiocarcinoma as ref.) | ||||
| Pancreatic cancer vs. ref. | 1.400 (0.457–4.288) | 0.556 | ||
| Other cancers vs. ref. | 0.714 (0.222–2.295) | 0.572 | ||
| Initial metallic stent length (80 mm [ref.] vs. others) | 1.962 (0.807–4.766) | 0.137 | ||
| Endoscopist for both procedures (same [ref.] vs. different) | 0.432 (0.143–1.301) | 0.136 | ||
| Guidewire insertion methods (BGI [ref.] vs. SGI) | 4.030 (1.573–10.328) | 0.004 | 4.682 (1.643–13.340) | 0.004 |
| Location of the lesion (CBD [ref.] vs. hilar biliary tract) | 2.213 (0.890–5.503) | 0.087 | 3.673 (1.236–10.915) | 0.019 |
| CBD diameter (≤ 12.5 mm [ref.] vs. > 12.5 mm) | 0.765 (0.317–1.847) | 0.551 | ||
| Duration of metallic stent patency (< 6 months [ref.] vs. ≥ 6 months) | 1.312 (0.542–3.177) | 0.547 | ||
Abbreviations: BGI, bent guidewire insertion; CBD, common bile duct; CI, confidence interval; EST, endoscopic sphincterotomy; ref., reference; OR, odds ratio; SGI, straight guidewire insertion.
FIGURE 4.
Analysis of risk factors for difficult cannulation. BGI, bent guidewire insertion; CBD, common bile duct; EST, endoscopic sphincterotomy; SGI, straight guidewire insertion.
4. Discussion
Through a retrospective analysis of 90 patients, we evaluated the feasibility and clinical outcomes of the BGI vs. SGI technique in endoscopic re‐intervention for patients who had experienced RMBO after the initial implantation of UMS. Our findings suggest that compared with the SGI technique, the BGI technique provides favorable outcomes in terms of the rates of difficult cannulation and technique transformation, the cannulation time, and the procedure time, supporting its potential as a superior approach and alternative to the conventional SGI technique in addressing this clinical challenge.
Endoscopic stent replacement is extensively utilized in the recanalization of UMS for RMBO. Nevertheless, the initial implantation of UMS and the subsequent tumor ingrowth may increase the risk of difficult re‐intervention. Therefore, accurate auxiliary cannulation of the guidewire becomes extremely crucial. We found that, in comparison with the SGI group, the BGI group had lower rates of difficult cannulation (19.1% vs. 48.8%, p = 0.006) and guidewire insertion technique transformation (4.3% vs. 44.2%, p < 0.001). This might be attributed to the fact that the BGI technique, which bends the distal end of the guidewire into a loop, effectively prevents the guidewire from slipping into the mesh of the UMS. Consequently, the BGI technique not only reduces the risk of difficult cannulation but also requires less time for precise guidewire manipulation and adjustment. In addition, the shortened procedure time and cannulation time by the BGI technique can lower the radiation exposure during the procedure. Moreover, when the procedure time is controlled within 30 min, the risk of post‐ERCP infection can be reduced [17]. The time interval from the initial stent placement to re‐intervention did not differ significantly between the two groups, suggesting that the differences in cannulation difficulty were less likely to be influenced by stent patency.
Despite these challenges, the technical and clinical success rates were comparable between the SGI and BGI groups in our study. Nevertheless, we should pay attention to the higher rate of overall procedure‐related complications in the SGI group (14.0% vs. 6.4%, p = 0.301), although it was not statistically significant. This tendency might be attributed to the repeated attempts during difficult cannulation, especially for less experienced practitioners. Previous studies have suggested that papillary cannulation attempts have been identified as an independent factor of post‐ERCP pancreatitis when they are repeated for over 5 times or last for 5 min [18, 19, 20]. However, large‐scale prospective studies are warranted to further validate these findings.
Moreover, we conducted subgroup analyses of the potential risk factors for difficult cannulation and found that difficult cannulation occurred more frequently when treated with the SGI technique (70.0% vs. 30.0%, p = 0.006), and these patients had higher rates of guidewire insertion technique transformation (50.0% vs. 10.0%, p < 0.001) and overall procedure‐related complications (26.7% vs. 1.7%, p = 0.001). These findings suggest that the SGI technique is more likely to require alternative techniques or additional interventions in complex anatomical conditions. The results also support the association between difficult cannulation and increased risks of procedure‐related complications [12, 21]. Longer cannulation time and procedure time in the difficult cannulation group further underscore the procedural challenges faced by such patient population.
In the current study, the SGI technique and hilar biliary tract lesions emerged as independent risk factors for difficult cannulation. These results are consistent with previous studies, which have recognized perihilar lesions as a substantial predictor of procedural complexity [22]. One possible explanation is that the angle formed between the hilar biliary tract and the CBD increases the difficulty in cannulation. The association between SGI and difficult cannulation can potentially be attributed to the technique's reliance on precise guidewire navigation, which can be particularly challenging in the presence of hilar lesions or distorted anatomy. The identification of SGI and hilar biliary tract lesions as independent risk factors for difficult cannulation has important clinical implications. These findings emphasize the necessity for a comprehensive pre‐procedural assessment, including imaging and anatomical evaluation, to identify patients who are at a high risk of difficult cannulation. Moreover, the higher procedural complexity and complication rates associated with SGI imply that this technique should be restricted to experienced operators and carefully selected patients. When difficult cannulation is anticipated, alternative techniques such as the BGI technique can be considered.
To our knowledge, this is the first study comparing the BGI and SGI techniques during intervention for RMBO. By directly comparing these two approaches, our findings suggest that the selection of guidewire insertion technique—although it may be regarded as a relatively minor technical aspect of the procedure—could have influenced procedural efficiency and clinical outcomes of the patients. Our findings provide clinically relevant information for guidewire selection during re‐intervention for RMBO and may be considered for the development of standardized strategies for guidewire insertion and the management of difficult cannulation.
There were several limitations to this study. First, the retrospective study design might have introduced selection bias and limited the generalizability of the findings. Second, because of this single‐center study design, the sample size might not be sufficient to detect subtle differences between groups or to perform more detailed subgroup analyses. Third, operator preference and experience inevitably might have influenced the initial choice of technique, making it difficult to fully eliminate confounding factors in comparative analysis. In addition, detailed clinical staging information was not consistently available. Although the distributions of tumor etiologies and lesion locations were comparable between the two groups, residual confounding factors related to tumor stage cannot be excluded. Nevertheless, inclusion of patients treated in clinical practice might enhance the ecological validity of the findings. Multicenter studies with larger sample sizes are warranted to validate our findings.
In conclusion, this study demonstrates that the BGI technique may be superior to the conventional SGI approach for managing RMBO after UMS placement. The SGI technique and hilar lesions are independent risk factors for difficult cannulation in patients requiring intervention for RMBO.
Funding
This work was supported by the Natural Science Foundation of Jiangxi Province of China (no. 20232BAB216016).
Conflicts of Interest
The authors declare no conflicts of interest.
Supporting information
Table S1: Clinical characteristics of patients with and without difficult biliary cannulation.
Table S2: Clinical outcomes of patients with and without difficult cannulation.
Acknowledgments
ChatGPT (OpenAI, GPT‐4) was adopted for language polishing of the main document. All authors have reviewed and revised all contents and take full responsibility for the final version.
Data Availability Statement
All the data generated in this study are not publicly available due to patient privacy constraints but are available upon reasonable request from the corresponding author.
References
- 1. Qumseya B. J., Jamil L. H., and Elmunzer B. J., “ASGE Guideline on the Role of Endoscopy in the Management of Malignant Hilar Obstruction,” Gastrointestinal Endoscopy 94, no. 2 (2021): 222–234.e22. [DOI] [PubMed] [Google Scholar]
- 2. Dumonceau J.‐M., Tringali A., Papanikolaou I. S., et al., “Endoscopic Biliary Stenting: Indications, Choice of Stents, and Results: European Society of Gastrointestinal Endoscopy (ESGE) Clinical Guideline – Updated October 2017,” Endoscopy 50, no. 9 (2018): 910–930. [DOI] [PubMed] [Google Scholar]
- 3. Al Hayek M., Khashab M., Spadaccini M., et al., “Self‐Expandable Metal Stents Versus Plastic Stents for Unresectable Malignant Hilar Biliary Obstruction: A Systematic Review and Meta‐Analysis of Reconstructed Individual Patient Data From Randomized Controlled Trials with Meta‐Regression,” Digestive and Liver Disease 58, no. 4 (2026): 456–463. [DOI] [PubMed] [Google Scholar]
- 4. Luo X., Huang Z., Ali K., and Hayat K., “Evaluating Safety and Efficacy of Plastic Versus Metal Stenting in Malignant Hilar Biliary Obstruction: A Systematic Review and Meta‐Analysis of Randomized Controlled Trials,” Postgraduate Medical Journal 101, no. 1195 (2025): 447–457. [DOI] [PubMed] [Google Scholar]
- 5. Takenaka M. and Kudo M., “Endoscopic Reintervention for Recurrence of Malignant Biliary Obstruction: Developing the Best Strategy,” Gut and Liver 16, no. 4 (2022): 525–534. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6. Park C. H., Park S. W., Jung J. H., Jung E. S., Kim J. H., and Park D. H., “Comparative Efficacy of Various Stents for Palliation in Patients With Malignant Extrahepatic Biliary Obstruction: A Systematic Review and Network Meta‐Analysis,” Journal of Personalized Medicine 11, no. 2 (2021): 86, 10.3390/jpm11020086. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7. Vanella G., Coluccio C., Cucchetti A., et al., “Fully Covered Versus Partially Covered Self‐Expandable Metal Stents for Palliation of Distal Malignant Biliary Obstruction: A Systematic Review and Meta‐Analysis,” Gastrointestinal Endoscopy 99, no. 3 (2024): 314–322.e19. [DOI] [PubMed] [Google Scholar]
- 8. Albers D., Schmidt A., Schiemer M., et al., “Impact of Endobiliary Radiofrequency Ablation on Biliary Drainage in Patients With Malignant Biliary Strictures Treated With Uncovered Self‐Expandable Metal Stents: A Randomized Controlled Multicenter Trial,” Gastrointestinal Endoscopy 96, no. 6 (2022): 970–979. [DOI] [PubMed] [Google Scholar]
- 9. Yamashita Y., Tachikawa A., Shimokawa T., et al., “Covered Versus Uncovered Metal Stent for Endoscopic Drainage of a Malignant Distal Biliary Obstruction: Meta‐Analysis,” Digestive Endoscopy 34, no. 5 (2022): 938–951. [DOI] [PubMed] [Google Scholar]
- 10. Park N., Jung M. K., Kim E. J., Paik W. H., and Cho J. H., “In‐Stent Radiofrequency Ablation With Uncovered Metal Stent Placement for Tumor Ingrowth/Overgrowth Causing Self‐Expandable Metal Stent Occlusion in Distal Malignant Biliary Obstruction: Multicenter Propensity Score‐Matched Study,” Gastrointestinal Endoscopy 97, no. 4 (2023): 694–703.e2. [DOI] [PubMed] [Google Scholar]
- 11. Testoni P. A., Mariani A., Aabakken L., et al., “Papillary Cannulation and Sphincterotomy Techniques at ERCP: European Society of Gastrointestinal Endoscopy (ESGE) Clinical Guideline,” Endoscopy 48, no. 7 (2016): 657–683. [DOI] [PubMed] [Google Scholar]
- 12. Lee Y. S., Cho C. M., Cho K. B., et al., “Difficult Biliary Cannulation From the Perspective of Post‐Endoscopic Retrograde Cholangiopancreatography Pancreatitis: Identifying the Optimal Timing for the Rescue Cannulation Technique,” Gut and Liver 15, no. 3 (2021): 459–465. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13. Mandai K., Inoue T., Yoshimoto T., Ogawa T., Uno K., and Yasuda K., “Evaluation of a Novel Easy Loop‐Forming Guidewire to Reduce Post–Endoscopic Retrograde Cholangiopancreatography Pancreatitis for Serial Pancreatic Juice Aspiration Cytologic Examination: A Propensity Score Matching Analysis,” Pancreas 53, no. 1 (2024): e49–e54. [DOI] [PubMed] [Google Scholar]
- 14. Sakai Y., Tsuyuguchi T., Sugiyama H., et al., “Prevention of Post‐Endoscopic Retrograde Cholangiopancreatography Pancreatitis by Pancreatic Duct Stenting Using a Loop‐Tipped Guidewire,” World Journal of Clinical Cases 4, no. 8 (2016): 213–218. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15. Pausawasdi N., Termsinsuk P., Charatcharoenwitthaya P., Limsrivilai J., and Kaosombatwattana U., “Development and Validation of a Risk Score for Predicting Clinical Success After Endobiliary Stenting for Malignant Biliary Obstruction,” PLoS One 17, no. 8 (2022): e0272918, 10.1371/journal.pone.0272918. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16. Cotton P. B., Eisen G. M., Aabakken L., et al., “A Lexicon for Endoscopic Adverse Events: Report of an ASGE Workshop,” Gastrointestinal Endoscopy 71, no. 3 (2010): 446–454. [DOI] [PubMed] [Google Scholar]
- 17. Yılmaz H. and Koçyiğit B., “Predictors of Postendoscopic Retrograde Cholangiopancreatography Associated Cholangitis: A Retrospective Cohort Study,” Turkish Journal of Medical Sciences 52, no. 1 (2022): 105–112. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18. Mariani A., Di Leo M., Giardullo N., et al., “Early Precut Sphincterotomy for Difficult Biliary Access to Reduce Post‐ERCP Pancreatitis: A Randomized Trial,” Endoscopy 48, no. 6 (2016): 530–535. [DOI] [PubMed] [Google Scholar]
- 19. Testoni P. A., Mariani A., Giussani A., et al., “Risk Factors for Post‐ERCP Pancreatitis in High‐ and Low‐Volume Centers and Among Expert and Non‐Expert Operators: A Prospective Multicenter Study,” American Journal of Gastroenterology 105, no. 8 (2010): 1753–1761. [DOI] [PubMed] [Google Scholar]
- 20. Crinò S. F., Aabakken L., Bapaye A., et al., “World Endoscopy Organization Guidelines on Endoscopic Retrograde Cholangiopancreatography Biliary Cannulation and Sphincterotomy Techniques,” Digestive Endoscopy 37, no. 10 (2025): 1029–1053. [DOI] [PubMed] [Google Scholar]
- 21. Dumonceau J.‐M., Kapral C., Aabakken L., et al., “ERCP‐Related Adverse Events: European Society of Gastrointestinal Endoscopy (ESGE) Guideline,” Endoscopy 52, no. 2 (2020): 127–149. [DOI] [PubMed] [Google Scholar]
- 22. Elmunzer B. J., Maranki J. L., Gómez V., et al., “ACG Clinical Guideline: Diagnosis and Management of Biliary Strictures,” American Journal of Gastroenterology 118, no. 3 (2023): 405–426. [DOI] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Table S1: Clinical characteristics of patients with and without difficult biliary cannulation.
Table S2: Clinical outcomes of patients with and without difficult cannulation.
Data Availability Statement
All the data generated in this study are not publicly available due to patient privacy constraints but are available upon reasonable request from the corresponding author.