Biliary Metal Stents Research Articles

Evaluation of the mechanical properties of current biliary self-expandable metallic stents: axial and radial force, and axial force zero border.

Mechanical properties (MPs) and axial and radial force (AF and RF) may influence the efficacy and complications of self-expandable metallic stent (SEMS) placement. We measured the MPs of various SEMSs and examined their influence on the SEMS clinical ability. We evaluated the MPs of 29 types of 10-mm SEMSs. RF was measured using a conventional measurement device. AF was measured using the conventional and new methods, and the correlation between the methods was evaluated. A high correlation in AFs was observed, as measured by the new and conventional manual methods. AF and RF scatterplots divided the SEMSs into three subgroups according to structure: hook-and-cross-type (low AF and RF), cross-type (high AF and low RF), and laser-cut-type (intermediate AF and high RF). The hook-and-cross-type had the largest axial force zero border (>20°), followed by the laser-cut and cross types. MPs were related to stent structure. Hook-and-cross-type SEMSs had a low AF and high axial force zero border and were considered safest because they caused minimal stress on the biliary wall. However, the increase in RF must be overcome.

Removal of Duckbill-type laser-cut anti-reflux metal stents: Clinical evaluation and in vitro study.

Duckbill-type metal stent (DMS) was the first laser-cut biliary metal stent with an anti-reflux valve. Removal of DMS is believed to be difficult and relevant reports are scarce. This study aims to investigate the feasibility of DMS removal. We retrospectively analyzed patients who underwent DMS removal between June 2019 and March 2022 to evaluate success rates and factors affecting outcomes. In addition, six different methods of DMS removal were reproduced in vitro, varying removal devices, angle of applied force, and grasped location. Extraction resistance, the distance of forceps stroke, and stent length after removal were compared. Forty patients were enrolled, and DMS removal was successful in 31 cases (78%). No adverse events were observed. Tumor ingrowth was evident in 78% (7/9) of failed cases. Patients receiving biliary metal stents for the first time (naïve cases), long indwelling time, longer stent, and stent tearing during removal were associated with unsuccessful stent removal. In the in vitro study, a larger force was required to remove the stent at an extraction angle of 120° than at 0°. Among cases in which force was applied at 120°, the load tended to be lower when rat-tooth forceps were applied horizontally across the stent. Stent removal was possible in a majority of cases. Deployment of additional stents inside DMS may be preferable to forceful removal in the presence of factors associated with difficult stent removals, such as tumor ingrowth, naïve cases, longer stents, long indwelling time, and stent tearing during removal.

Development of novel biliary metal stent with coil-spring structure and its application in vivo swine biliary stricture model.

As of date, endoscopic biliary stenting with plastic stent (PS) and self-expandable metal stent (SEMS) have been widely used for the palliation of biliary tract strictures. However, these two stents have several limitations regarding the management of biliary strictures caused by intrahepatic and hilar cholangiocarcinoma. PS has short patency and also risks bile duct injury and bowel perforation. SEMS is difficult to revise when occluded by tumor overgrowth. To compensate for such shortcomings, we developed a novel biliary metal stent with coil-spring structure. The aim of this study was to investigate the feasibility and efficacy of the novel stent in a swine model. The biliary stricture model was prepared in six mini-pigs using endobiliary radiofrequency ablation. Conventional PS (n=2) and novel stents (n=4) were deployed endoscopically. Technical success was defined as successful stent placement and clinical success was defined as >50% reduction of serum bilirubin level. Adverse events, stent migration, and endoscopic removability for one month after stenting were also assessed. The biliary stricture was successfully created in all animals. The technical success rate was 100 %, and the clinical success rate was 50% in the PS group and 75% in the novel stent group. In the novel stent group, the median pre- and post-treatment serum bilirubin levels were 3.94 and 0.3 mg/dL. Stent migration occurred in two pigs and two stents were removed by endoscopy. There was no stent-related mortality. The newly designed biliary metal stent was feasible and effective in a swine biliary stricture model. Further studies are needed to verify the usefulness of the novel stent in the management of biliary strictures.

Impact of Extended Antibiotic Use After Pancreaticoduodenectomy for Patients with Preoperative Metallic Biliary Stenting Treated with Neoadjuvant Chemotherapy

IntroductionPancreaticoduodenectomy (PD) remains a complex surgical procedure with infectious complications affecting nearly 50% of patients. Patients who undergo biliary drainage with stent placement prior to neoadjuvant treatment (NAT) reportedly have higher infection rates following PD. The aim of the current study is to evaluate the differences in postoperative infectious complication rates based on the duration of post operative prophylactic antibiotics in patients with indwelling metal biliary stent who had NAT. MethodsA retrospective institutional pancreatic cancer database was queried for patients who had a metal biliary stent placed prior to NAT initiation, followed by subsequent PD between 2014 and 2021. Duration of postoperative prophylactic antibiotics was defined as short (SC: ≤ 24 h) or extended (EC: > 24 h–7 days). The primary outcome of interest was surgical site infection (SSI). ResultsTwo hundred and ninety-five (n = 295) patients were identified of which the majority (n = 205, 69.5%) received a short course of antibiotics postoperatively. Baseline characteristics were similar between the two cohorts including age, sex, BMI, and comorbidity index. EC patients received more NAT cycles (4 vs. 3, p < 0.001) and underwent an open PD more frequently (61.8% vs. 41.0%, p < 0.001). SSI occurred in 64 (21.7%) patients; SC cohort: 54, 26.3% vs. EC cohort:10, 11.1%, (p = 0.003). Additionally, the SC cohort demonstrated a higher incidence of major complications (Clavien-Dindo ≥ 3: 51 [24.9%] vs. 13 [14.4%], p = 0.045). On the logistic regression model examining factors associated with SSI, higher BMI (continuous variable) was associated with increased odds of SSI (OR: 1.05 [95%CI: 1.00, 1.10, p = 0.040), while EC was protective (OR: 0.36 [95%CI: 0.17, 0.75], p = 0.007). ConclusionsThese data suggest that an extended course of perioperative antibiotic correlates with reductions in SSI and major morbidity following PD in patients with a metallic biliary stent placed prior to NAT course. These results require validation in a future randomized clinical trial examining a larger cohort of patients with further emphasis on the types of perioperative antibiotics administered.

Bilateral stent-in-stent placement of biliary metal stents with a slim delivery system through an ultraslim endoscope.

Bilateral stent-in-stent placement of biliary metal stents with a slim delivery system through an ultraslim endoscope.

Bending the distal tip of a guidewire aids in cannulation of an occluded uncovered biliary metal stent.

Biliary metal stent implantation is an effective treatment for malignant obstructive jaundice. But it's well known that stents put in for a long time can become occluded and cause jaundice and cholangitis. At this time, endoscopic intervention is usually required to replace the stent or re-insert the stent. Re-cannulation for metal stent occlusion is challenging because the guide wire may pass through the side holes of the uncovered metal stents, resulting in prolonged surgical time and exposure to radiation. Here we present a small tip that may help endoscopists complete the re-cannulation of an uncovered metal stent in a very short time.

Long-term outcomes of duckbill-type anti-reflux metal stents versus conventional covered metal stents in reinterventions after covered biliary metal stent dysfunction in unresectable pancreatic cancer.

The use of duckbill-type anti-reflux metal stents (DMS) in reinterventions after covered metal stent (CMS) dysfunction has been reported in patients with distal malignant biliary obstruction (MBO). However, the superiority of DMS over conventional CMS (c-CMS) has not been established. Therefore, we conducted this retrospective study to evaluate the long-term efficacy and safety of DMS as a second stent in comparison with c-CMS. We investigated consecutive patients with distal MBO due to unresectable pancreatic cancer who underwent reintervention after dysfunction of initial biliary CMS at our institution. We compared causes of recurrent biliary obstruction (RBO), time to RBO (TRBO), adverse events (AEs), and reintervention rates of DMS and c-CMS in this stenting. A total of 76 patients were included (DMS 41 and c-CMS 35). While overall RBO rates were similar between the two groups (46% vs. 63%, p = 0.172), RBO due to non-occlusion cholangitis tended to be less frequent in the DMS group than in the c-CMS group (2% vs. 14%, p = 0.089). Median TRBO was significantly longer in the DMS group (286days vs. 112days, p = 0.029). DMS was identified as the only significant risk factor for TRBO (hazard ratio, 0.52; p = 0.044). Overall AE rates were significantly lower in the DMS group (2% vs. 23%, p = 0.010), with non-occlusion cholangitis being the most common AE in the c-CMS group. Endoscopic reintervention was successfully performed in all patients in both groups, despite failed stent removal in 15% of patients in DMS group. DMS was associated with a significantly longer TRBO and lower rate of AEs compared with c-CMS in reinterventions after initial CMS dysfunction. DMS may be preferable to c-CMS as a second stent after biliary CMS dysfunction.

EUS-guided choledochoduodenostomy using a lumen-apposing metal stent in a patient with preexisting duodenal stent and ascites.

Video 1EUS-guided choledochoduodenostomy using a lumen-apposing metal stent in a patient with preexisting duodenal stent and ascites.

S1923 Abutting Percutaneous Drains Can Jeopardize Healing of Post-Cholecystectomy Bile Leaks

S1923 Abutting Percutaneous Drains Can Jeopardize Healing of Post-Cholecystectomy Bile Leaks

Heating of metallic biliary stents during magnetic hyperthermia of patients with pancreatic ductal adenocarcinoma: an in silico study

Objective To investigate the eddy current heating that occurs in metallic biliary stents during magnetic hyperthermia treatments and to assess whether these implants should continue to be an exclusion criterion for potential patients. Methods Computer simulations were run on stent heating during the hyperthermia treatment of local pancreatic tumors (5–15 mT fields at 300 kHz for 30 min), considering factors such as wire diameter, type of stent alloy, and field orientation. Maxwell’s equations were solved numerically in a bile duct model, including the secondary field produced by the stents. The heat exchange problem was solved through a modified version of the Pennes’ bioheat equation assuming a temperature dependency of blood perfusion and metabolic heat. Results The choice of alloy has a large impact on the stent heating, preferring those having a lower electrical conductivity. Only for low field intensities (5 mT) and for some of the bile duct tissue layers the produced heating can be considered safe. The orientation of the applied field with respect to the stent wires can give rise to the onset of regions with different heating levels depending on the shape that the stent has finally adopted according to the body’s posture. Bile helps to partially dissipate the heat that is generated in the lumen of the bile duct, but not at a sufficient rate. Conclusion The safety of patients with pancreatic cancer wearing metallic biliary stents during magnetic hyperthermia treatments cannot be fully assured under the most common treatment parameters.

Combined stent-by-stent and stent-in-stent biliary metal stent deployment using a forward-oblique viewing echoendoscope in surgically altered anatomy.

Combined stent-by-stent and stent-in-stent biliary metal stent deployment using a forward-oblique viewing echoendoscope in surgically altered anatomy.

Biliary metal stents should be placed near the hilar duct in distal malignant biliary stricture patients.

BACKGROUNDEndoscopic biliary drainage using a self-expandable metallic stent (SEMS) has been widely performed to treat distal malignant biliary obstruction (DMBO). However, the optimal position of the stent remains unclear.AIMTo determine the ideal position for SEMS placement.METHODSIn total, 135 DMBO patients underwent SEMS (uncovered or covered) placement over a ten-year period. A total of 127 patients with biliary obstruction between the junction of the cystic duct and Vater’s papilla were enrolled. An SEMS was placed through the upper common bile duct 2 cm from the biliary hilar duct in 83 patients (Hilar group) or near the top of the biliary obstruction in 44 patients (Lower group). Technical and functional success, adverse events, and risk factors for SEMS dysfunction were evaluated.RESULTSThe stent patency period was significantly longer in the Hilar group than in the Lower group (P value < 0.01). In multivariate analysis, the only statistically significant risk factor for SEMS dysfunction was being in the Lower group (hazard ratio: 9.94, 95% confidence interval: 2.25–44.0, P < 0.01).CONCLUSIONA longer patency period was achieved by positioning the SEMS near the biliary hilar duct.

Usefulness of a circumferential argon plasma coagulation probe in trimming a dislocated distal biliary metal stent.

Usefulness of a circumferential argon plasma coagulation probe in trimming a dislocated distal biliary metal stent.

Comparison of surgical biliary bypass and biliary metallic stents for palliation of incurable malignant distal bile duct obstruction: A prospective observational study

: Management of obstructive jaundice from periampullary and pancreatic head malignancies is mostly palliative. With advancements in endoscopic and stent technology and instrumentation, endoscopic interventions are gaining popularity and acceptance over surgical relief of jaundice. To study efficacy of surgical biliary bypass over biliary metallic stents for palliation of incurable malignant distal bile duct obstructionProspective observational study was carried out among 77 patients withincurable malignant distal bile duct obstruction. 45 of them chose to undergo surgical bypass while 32 agreed to undergo metallic stenting. Parameters like improvement in jaundice, procedure related morbidities, need for re-hospitalization, need for re-intervention, quality of life and survival were compared in two groups. Chi square test and t test were applied to compare two groups. : There was prompt and good relief of jaundice in both groups. There was one procedure related mortality in each group. The morbidities were comparable. The stented patients were hospitalized for a cumulative mean period of 34.1 days compared to 14.2 days in the surgical bypass group (p= 0.0001). The global quality of life, pain, nausea, vomiting and appetite were significantly better in the surgical bypass group. There was significantly improved overall survival in the surgical bypass group (163.5 days vs. 150 days, p= 0.0001). urgical bypass offers safe and superior palliation to obstructive jaundice from inoperable periampullary and pancreatic head cancer.

An Unexpected Case of Metal Biliary Stent Fracture Detected by Contrast Enhanced 18F-FDG PET/C

18F-FDG PET/CT is an useful diagnostic tool for cancer patients. In our routine practice, we perform a significant number of PET/CT scans in association with contrast enhanced CT, to assess resectability of abdominal tumors or to evaluate distant brain and liver metastases. We documented an unexpected emergency disease during a contrast enhanced 18F-FDG PET/CT. In a 63-year-old male patient, examined during follow-up of lung cancer, no sites of disease relapse were detected at PET/CT; nevertheless, diffuse tracer uptake was detected along the outline of a biliary stent. Correlative contrast enhanced CT diagnosed fracture of a metallic biliary stent without any evidence of cancer involvement. Patient was referred to the local department of surgery for substitution of the biliary stent. Although rare, unexpected emergency diseases requiring urgent management are detected using 18FFDG PET/CT. Correlative CT should be carefully evaluated in order to avoid delays in diagnosis, potentially leading to poorer prognosis.

Rate of pancreatic cancer following a negative endoscopic ultrasound and associated factors.

BACKGROUND : Data are limited regarding pancreatic cancer diagnosed following a pancreaticobiliary endoscopic ultrasound (EUS) that does not diagnose pancreatic cancer. We have studied the frequency of, and factors associated with, post-EUS pancreatic cancer (PEPC) and 1-year mortality. METHODS : Between 2010 and 2017, patients with pancreatic cancer and a preceding pancreaticobiliary EUS were identified in a national cohort using Hospital Episode Statistics. Patients with a pancreaticobiliary EUS 6-18 months before a later pancreatic cancer diagnosis were the PEPC cases; controls were those with pancreatic cancer diagnosed within 6 months of pancreaticobiliary EUS. Multivariable logistic regression models examined the factors associated with PEPC and a Cox regression model examined factors associated with 1-year cumulative mortality. RESULTS : 9363 pancreatic cancer patients were studied; 93.5 % identified as controls (men 53.2 %; median age 68 [interquartile range (IQR) 61-75]); 6.5 % as PEPC cases (men 58.2 %; median age 69 [IQR 61-77]). PEPC was associated with older age (≥ 75 years compared with &lt; 65 years, odds ratio [OR] 1.42, 95 %CI 1.15-1.76), increasing co-morbidity (Charlson co-morbidity score &gt; 5, OR 1.90, 95 %CI 1.49-2.43), chronic pancreatitis (OR 3.13, 95 %CI 2.50-3.92), and diabetes mellitus (OR 1.58, 95 %CI 1.31-1.90). Metal biliary stents (OR 0.57, 95 %CI 0.38-0.86) and EUS-FNA (OR 0.49, 95 %CI 0.41-0.58) were inversely associated with PEPC. PEPC was associated with a higher cumulative mortality at 1 year (hazard ratio 1.12, 95 %CI 1.02-1.24), with only 14 % of PEPC patients (95 %CI 12 %-17 %) having a surgical resection, compared with 21 % (95 %CI 20 %-22 %) of controls. CONCLUSIONS : PEPC occurred in 6.5 % of patients and was associated with chronic pancreatitis, older age, more co-morbidities, and specifically diabetes mellitus. PEPC was associated with a worse prognosis and lower surgical resection rates.

Symptomatic pancreatic lipoma managed with a metallic biliary stent: Case report.

IntroductionMesenchymal tumors comprise only 1 to 2% of all pancreatic tumors, being lipomas a rare variant of mesenchymal tumors of the pancreas.Presentation of caseThis is the report of an 82-year-old woman who presented at the medical emergency room in a fourth level clinic with five days of nausea evolution, emesis, jaundice, coluria, acholia, and abdominal pain in the right hypochondrium. Diagnostic imaging and ultrasonography discovered and characterized a significant dilation of the intra and extrahepatic bile duct, caused by the presence of a mass in the head of the pancreas of lipomatous origin. The obstruction was successfully managed with a metallic fully covered removable biliary stent.DiscussionSome studies have reported the incidence of pancreatic lipoma being 0.08% and 0.012%, and the vast majority of them (>95%) are asymptomatic and properly handled without intervention, however, symptomatic tumors require surgical treatment. In our case, the surgical treatment was not suitable because of her multiple comorbidities, cardiovascular risk and advanced age. Our management continued to be a minimally invasive approach, without general anesthesia and good postoperative results.ConclusionTo the best of our knowledge we report the first case of symptomatic pancreatic lipoma in Colombia with unique management, and the second in Latin America.

Jailbreaking a metal biliary stent through a duodenal stent.

Video 1.

Rupture of a pseudoaneurysm after uncovered self-expanding biliary metallic stent placement.

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Percutaneous Endoluminal Radiofrequency Ablation of Occluded Biliary Metal Stent in Malignancy Using Monopolar Technique: A Feasibility Study.

To prove feasibility and safety of percutaneous endoluminal radiofrequency ablation (eRFA) using a monopolar approach in treatment of occluded biliary stent in malignancy. The study included 11 patients with occluded biliary metal stent that had been implanted due to malignant biliary obstruction. All underwent metal stent recanalization by percutaneous eRFA in monopolar setting. Sixteen eRFA procedures were performed under fluoroscopic guidance with an EndoHPB 8F radiofrequency ablation catheter. The effect of stent recanalization was assessed based upon change from pre- to post-procedural diameter of the patent lumen of the metal stent (Wilcoxon test), primary and secondary stent patency (compared by log-rank test), catheter-free period, and overall survival. Adverse events were evaluated according to Common Terminology Criteria for Adverse Events (CTCEA) 4.0. Recanalization of the metal stent by monopolar radiofrequency ablation was successful in all 11 patients. Diameter of the patent lumen of the stent significantly widened after the eRFA inside the stent (median 2 vs. 7mm, p = 0.003). Grade 1 complications were observed in one-third of procedures. Median stent patency after recanalization by eRFA was non-inferior to primary metal stent patency (154 vs. 161days, p = 0.27). Median catheter-free survival and overall survival after stent recanalization were 149 and 210days, respectively. Endoluminal radiofrequency ablation in monopolar setting was shown to be a feasible and safe method for recanalization of occluded biliary metal stents. Level 4, Case Series.