BACKGROUND/AIMS: A drug-eluting stent for unresectable malignant biliary obstruction was developed to increase stent patency by preventing tumor ingrowth. The safety and efficacy of a new generation of metallic stents covered with a paclitaxel-incorporated membrane using a Pluronic® mixture (MSCPM-II) were compared prospectively with those of covered metal stents (CMSs) in patients with malignant biliary obstructions. METHODS: This study was initially designed as a prospective randomized trial but was closed early because of a high incidence of early occlusion. Therefore, the data were analyzed using the intent-to-treat method. A total of 72 patients with unresectable distal malignant biliary obstructions were prospectively enrolled. RESULTS: The two groups did not differ significantly in basic characteristics and mean follow-up period (MSCPM-II 194 days vs CMS 277 days, p=0.063). Stent occlusion occurred in 14 patients (35%) who received MSCPM-II and in seven patients (21.9%) who received CMSs. Stent patency and survival time did not significantly differ between the two groups (p=0.355 and p=0.570). The complications were mild and resolved by conservative management in both groups. CONCLUSIONS: There were no significant differences in stent patency or patient survival in MSCPM-II and CMS patients with malignant biliary obstructions.
Biliary Tract Neoplasms ; Drug-Eluting Stents ; Follow-Up Studies ; Humans ; Incidence ; Membranes* ; Methods ; Paclitaxel* ; Pancreatic Neoplasms ; Prospective Studies* ; Self Expandable Metallic Stents ; Stents*

This review article presents the radiological options for management of malignant gastric outflow obstruction distal to the pylorus. We place these options in context with surgical and endoscopic alternatives and recommend their use, particularly in those institutions where endoscopic alternatives may not be readily available.
Duodenal Obstruction ; Pylorus* ; Self Expandable Metallic Stents ; Technology, Radiologic

BACKGROUND/AIMS: Metallic stents designed to relieve malignant biliary obstruction are susceptible to occlusive tumor ingrowth or overgrowth. In a previous report, we described metallic stents covered with paclitaxel-incorporated membrane (MSCPM-I, II) to prevent occlusion from tumor ingrowth via antitumor effect. This new generation paclitaxel-eluting biliary stent is further endowed with sodium caprate (MSCPM-III) for enhanced drug delivery. The purpose of this study is to examine the safety of its drug delivery system in the porcine biliary tract. METHODS: MSCPM-III (10% [wt/vol] paclitaxel) and covered metal stents (CMSs) were endoscopically inserted in porcine bile ducts in vivo. Histologic biliary changes, levels of paclitaxel released, and various serum analytes (albumin, alkaline phosphate, aspartate transaminase, alanine transaminase, total protein, total bilirubin, and direct bilirubin) were assessed. RESULTS: Based on the intensity of reactive inflammation and fibrosis, changes in porcine biliary epithelium secondary to implanted MSCPM-III were deemed acceptable (i.e., safe). Histologic features in the MSCPM-III and CMS groups did not differ significantly. In a related serum analysis, paclitaxel release from MSCPM-III stents was below the limit of detection for 28 days. Biochemical analyses were also similar for the two groups, and no evidence of hepatic or renal toxicity was found in animals receiving MSCPM-III stents. CONCLUSIONS: In a prototypic porcine trial, this newly devised metal biliary stent incorporating both paclitaxel and sodium caprate appears to be safe in the porcine bile duct.
Alanine Transaminase ; Animals ; Aspartate Aminotransferases ; Bile Ducts ; Biliary Tract Neoplasms ; Biliary Tract ; Bilirubin ; Drug Delivery Systems ; Drug-Eluting Stents ; Epithelium ; Fibrosis ; Inflammation ; Limit of Detection ; Membranes ; Paclitaxel ; Pancreatic Neoplasms ; Self Expandable Metallic Stents ; Sodium ; Stents

Endoscopic treatment of biliary strictures involving plastic stent placement has been used widely. The use of self-expandable metal stents (SEMSs) has been described for anastomotic strictures following liver transplantation (LT). This review aimed to assess and compare the efficacy of plastic stents with SEMS in LT patients. Information was retrieved regarding technical success, stricture resolution, the number of endoscopic retrograde cholangiography procedures, follow-up, immediate, and late complications. Eight studies involving plastic stents had a stricture resolution rate of 84.5%, with the rates ranging from 63% to 100%. These rates are comparable with the stricture resolution rate of 75% determined from six studies that involved 236 patients who received metal stents and the rates ranged from 53% to 81%. The observed success rate for metal stents used to manage post-LT anastomotic biliary strictures was below the reported rate for multiple plastic stents. Hence, the currently available metal stents should not be offered for the management of post-LT anastomotic biliary strictures.
Cholangiography ; Constriction, Pathologic* ; Follow-Up Studies ; Humans ; Liver Transplantation* ; Liver* ; Plastics ; Self Expandable Metallic Stents ; Stents

Acute colonic obstruction secondary to left-colonic malignancy remains a common emergency condition. Traditional management is emergency surgery and has high morbidity and mortality. Self expandable metallic stents (SEMS) promised to improve morbidity and mortality, stoma rates and hospital stay. SEMS use in the potentially curative setting, as a bridge to surgery, is associated with an improved stoma rate and morbidity, but has no mortality benefit. There are concerns about oncological safety with higher local recurrence rates, thus SEMS is not recommended in this setting unless the patient has increased surgical risk and would benefit from a period of recovery prior to surgery. SEMS has a definite role in the palliative setting, for both patients with incurable disease or those with a high surgical risk. SEMS is associated with improved morbidity, mortality, and stoma rates. The technique for SEMS insertion is now well established but it is still unclear whether covered or uncovered stents are better.
Colon* ; Colonic Neoplasms* ; Emergencies ; Humans ; Intestinal Obstruction ; Length of Stay ; Mortality ; Recurrence ; Self Expandable Metallic Stents ; Stents*

Biliary drainage is required for the management of unresectable malignant hilar biliary obstruction (UMHBO), and endoscopic transpapillary drainage is the first-line therapy because it is less invasive. Self-expandable metallic stents (SEMSs) are superior to plastic stents because they have longer stent patency and are more cost-effective. Endoscopic bilateral SEMS placement is technically challenging compared to unilateral placement. However, recent developments in devices and techniques have facilitated bilateral SEMS placement. There are two methods for bilateral hilar SEMS placement for UMHBO: side-by-side (SBS) and stent-in-stent (SIS). Sequential SBS was commonly conducted for bilateral hilar SEMS placement. In a new and thinner delivery system that was developed for SEM placement, two SEMSs could be simultaneously inserted and deployed through the working channel. This new bilateral stenting method enabled us to accomplish simultaneous SBS placement, which increased the success rate of SBS. Insertion of the guidewire and delivery of the second SEMS through the mesh of the first SEMS is challenging in SIS. Newly designed or modified SEMSs that are suitable for SIS have been developed to overcome this challenge, and these SEMSs have facilitated SIS. Uncovered SEMS has been commonly used for hilar SEMS placement, but covered SEMS (CSEMS) is another option for hilar SEMS placement, because CSEMS prevents tumor ingrowth and allows for removal of the stent for re-intervention. Therefore, CSEMS can be used for bilateral SEMS placement in SBS. There are many methods and kinds of SEMS available for bilateral SEMS placement. However, due to lack of evidence, there is no consensus on whether SBS or SIS is optimal for bilateral hilar SEMS placement. In this review, we compared various outcomes between SBS and SIS from previous studies, to clarify which method is better for bilateral SEMS placement for UMHBO.
Cholangiopancreatography, Endoscopic Retrograde ; Cholestasis ; Consensus ; Drainage ; Klatskin Tumor ; Methods ; Plastics ; Self Expandable Metallic Stents ; Stents

BACKGROUND/AIMS: Although endoscopic bilateral stent-in-stent placement is challenging, many recent studies have reported promising outcomes regarding technical success and endoscopic re-intervention. This study aimed to evaluate the technical accessibility of stent-in-stent placement using large cell-type stents in patients with inoperable malignant hilar biliary obstruction. METHODS: Forty-three patients with inoperable malignant hilar biliary obstruction from four academic centers were prospectively enrolled from March 2013 to June 2015. RESULTS: Bilateral stent-in-stent placement using two large cell-type stents was successfully performed in 88.4% of the patients (38/43). In four of the five cases with technical failure, the delivery sheath of the second stent became caught in the hook-cross-type vertex of the large cell of the first stent, and subsequent attempts to pass a guidewire and stent assembly through the mesh failed. Functional success was achieved in all cases of technical success. Stent occlusion occurred in 63.2% of the patients (24/38), with a median patient survival of 300 days. The median stent patency was 198 days. The stent patency rate was 82.9%, 63.1%, and 32.1% at 3, 6, and 12 months postoperatively, respectively. Endoscopic re-intervention was performed in 14 patients, whereas 10 underwent percutaneous drainage. CONCLUSIONS: Large cell-type stents for endoscopic bilateral stent-in-stent placement had acceptable functional success and stent patency when technically successful. However, the technical difficulty associated with the entanglement of the second stent delivery sheath in the hook-cross-type vertex of the first stent may preclude large cell-type stents from being considered as a dedicated standard tool for stent-in-stent placement.
Cholangiopancreatography, Endoscopic Retrograde ; Cholestasis, Intrahepatic ; Drainage ; Humans ; Klatskin Tumor ; Prospective Studies* ; Self Expandable Metallic Stents ; Stents*

Surgery has been the standard treatment for perforated duodenal ulcers, with mostly good results. However, the resolution of postoperative leakage after primary repair of perforated duodenal ulcer remains challenging. There are several choices for re-operation required in persistent leakage from perforated duodenal ulcers. However, many of these choices are complicated surgical procedures requiring prolonged general anesthesia that may increase the chances of morbidity and mortality. Several recent reports have demonstrated postoperative leakage after primary repair of a perforated duodenal ulcer treated with endoscopic insertion using a covered self-expandable metallic stent, with good clinical results. We report a case with postoperative leakage after primary repair of a perforated duodenal ulcer treated using a covered self-expandable metallic stent.
Anesthesia, General ; Duodenal Ulcer* ; Mortality ; Peptic Ulcer Perforation ; Self Expandable Metallic Stents ; Stents*

Cholangioarcinoma is a rare but dreadful malignancy which poses much difficulties in the management. If detected early with only localized disease, curative resection is possible. However, most patients present in the late stages of the disease, which are managed with endoscopic biliary drainage and/or chemoradiation. Liver transplantation offers a possibility for cure in the distal and the perihilar tumors for selected candidates. Local treatments, such as hepatic artery-based therapies, brachytherapy, and photodynamic therapy, may offer some benefit in cases of the advanced disease. In this review, we will assess the role of preoperative biliary drainage, how best to drain biliary obstruction, and the intricate details of various treatments that are currently available.
Brachytherapy ; Cholangiocarcinoma* ; Cholestasis ; Drainage ; Endosonography ; Humans ; Liver Transplantation ; Photochemotherapy ; Self Expandable Metallic Stents

In order to evaluate the safety performance of self-expandable NiTi alloy stents systematically, the dynamic safety factor drawn up by International Organization for Standardization, was used to quantitatively reflect the safety performance of stents. Based on the constitutive model of super-elastic memory alloy material in Abaqus and uniaxial tensile test data of NiTi alloy tube, finite element method and experiments on accelerated fatigue life were carried out to simulate the self-expansion process and the shape change process under the action of high and low blood pressure for three -type stents of 8×30 mm, 10×30 mm, 12×30 mm. By analyzing the changes of stress and strain of self-expanding NiTi alloy stent, the maximum stress and strain, stress concentration position, fatigue strength and possible failure modes were studied, thus the dynamic safety factor of stent was calculated. The results showed that the maximum stress and plastic strain of the stent increased with the increase of grip pressure, but the maximum stress and strain distribution area of the stent had no significant change, which were all concentrated in the inner arc between the support and the connector. The dynamic safety factors of the three stents were 1.31, 1.23 and 1.14, respectively, which indicates that the three stents have better safety and reliability, and can meet the fatigue life requirements of more than 10 years, and safety performance of the three stents decreases with the increase of stent's original diameter.
Alloys ; Finite Element Analysis ; Nickel ; Reproducibility of Results ; Self Expandable Metallic Stents ; Stress, Mechanical ; Titanium