Obstructive colorectal cancer is a common malignant bowel obstruction. Colostomy or colostomy following tumor resection may be the first choice for emergency surgery. The intestinal and systemic conditions of patients undergoing emergency surgery are often poor, and patients need to undergo multiple operations, which increase the surgical risk and economic burden and reduce the quality of life of patients. Poor intraoperative visualization may also affect the radical operation of emergency surgery. Transanal decompression tube (TDT) can rapidly decompress and drain the obstructed bowel, effectively relieve obstruction symptoms, and improve the success rate of primary radical resection. The TDT squeeze the tumor lightly, causing no spread of tumor cells, and is cheap, but the cavity of transanal decompression tube is small and easily blocked, and requires tedious flushing or regular replacement. Self-expanding metallic stents (SEMS) can relieve intestinal obstruction effectively, provide sufficient preparation time for preoperative examination and improvement of nutritional status. By improving patient's tolerance to radical surgery, SEMS might be used as an important treatment strategy choice for obstructive colorectal cancer. However, SEMS may squeeze the tumor, leading to the spread of tumor cells, increase the recurrence rate and metastasis rate, and reduce the survival rate. Moreover, intestinal wall edema still existed during the operation following SEMS, and the rate of ostomy after anastomosis was as high as 34%. We hypothesized that prolonging the interval between stent insertion and surgery to 2 months, with neoadjuvant chemotherapy administered during this interval (SEMS-neoadjuvant chemotherapy strategy), would help improve outcomes. The SEMS-neoadjuvant chemotherapy strategy is a safe, effective, and well tolerated treatment approach with a high laparoscopic resection rate, low stoma formation rate and improvement in the overall survival for patients with left-sided colon cancer obstruction. The patient physical status is improved, the primary tumor is downstaged, and intestinal wall edema is relieved during the relatively longer interval between SEMS placement and surgery. The SEMS-neoadjuvant chemotherapy strategy may be a preferred therapeutic strategy for obstructive left colon cancer.
Humans ; Quality of Life ; Self Expandable Metallic Stents/adverse effects* ; Colonic Neoplasms/surgery* ; Stents/adverse effects* ; Intestinal Obstruction/surgery* ; Treatment Outcome ; Colorectal Neoplasms/complications* ; Retrospective Studies

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

BACKGROUND/AIMS: Radiopaque metal markers are required to improve X-ray absorption by self-expandable metal stents (SEMSs) to enable precise stent placement. A new tantalum radiopaque marker was recently developed using an ultrasonic spray technique. The aim of the present study was to evaluate the safety and visibility of tantalum markers. METHODS: A total of three beagle dogs were used for a gastrointestinal tract absorption test. Five tantalum markers were placed in the stomach of each dog endoscopically. Excreted tantalum markers were collected, and their weights were compared to the original weights. In radiopacity tests, marker radiopacities on X-ray images were quantified using ImageJ software and compared with those of commercially available metal markers. Finally, the radiographic images of six patients who underwent biliary SEMS placement using tantalum marker Nitinol SEMSs (n=3) or gold marker Nitinol SEMSs (n=3) were compared with respect to marker brightness on fluoroscopic images. RESULTS: Absorption testing showed that the marker structures and weights were unaffected. Radiopacity tests showed that the mean brightness and total brightness scores were greater for tantalum markers (226.22 and 757, respectively) than for gold (A, 209 and 355, respectively; B, 204.96 and 394, respectively; C, 194.34 and 281, respectively) or platinum markers (D, 203.6 and 98, respectively). On fluoroscopic images, tantalum markers had higher brightness and total brightness scores (41.47 and 497.67, respectively) in human bile ducts than gold markers (28.37 and 227, respectively). CONCLUSIONS: Tantalum markers were found to be more visible than other commercially available markers in X-ray images and to be resistant to gastrointestinal absorption.
Absorption ; Animals ; Bile Ducts ; Dogs ; Gastrointestinal Absorption ; Gastrointestinal Tract ; Humans ; Platinum ; Self Expandable Metallic Stents ; Stents ; Stomach ; Tantalum ; Ultrasonics ; Weights and Measures

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

Nitinol self expandable metal stents are increasingly utilised for malignant obstruction in the proximal gastrointestinal tract. We describe a case in which repeated fracture of proximal duodenal stents with dissolution of the nitinol wire skeleton and covering membranes occurred in a long term cancer survivor. This necessitated placement of 4 stents for symptom control and to allow oral feeding until the patient's death 20 months after the initial stent was inserted. Fracture of gastric and duodenal stents has rarely been described previously, some incidences of which were considered due to mechanical causes. Dissolution of stent metal skeletons has not previously been recognised in gastroduodenal stents but has been described in an oesophageal stent subject to reflux of gastric content and a biochemical mechanism has been proposed. With modern oncological treatment the prospect of patients outliving their stents is increasing and the need for repeat procedures should form part of the consent process.
Gastric Outlet Obstruction ; Gastrointestinal Tract ; Humans ; Incidence ; Membranes ; Prosthesis Failure ; Radiology, Interventional ; Self Expandable Metallic Stents ; Skeleton ; Stents ; Survivors

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

Placement of a plastic or metal stent via endoscopic retrograde cholangiopancreatography (ERCP) currently serves as the first-line procedure for obstructive jaundice and acute cholangitis. Dysfunction of the biliary stent causes recurrence of symptoms and often requires reinterventions and hospitalizations. Therefore, duration of stent patency is commonly used as the primary endpoint in clinical studies of biliary stents. However, owing to considerable heterogeneity between studies in reporting of biliary stent patency, it has been difficult to compare and integrate results of independent studies. There has been between-study heterogeneity in definitions of stent patency, statistics reported for survival curves of stent patency, and methods to treat censored cases. In addition to stent occlusion, stent migration is a major cause of recurrent biliary obstruction after covered metal stent placement, which further complicates the reporting of stent patency. Reporting of functional success and adverse events has been also inconsistent between the studies. From the perspective of evidence-based medicine, the variations in the definitions of outcome variables potentially hinder robust meta-analyses. To overcome the issues due to the lack of outcome reporting guidelines on the topic, the TOKYO criteria 2014 for reporting outcomes associated with endoscopic transpapillary placement of biliary stents have been proposed. Due to their comprehensiveness, the TOKYO criteria can be readily utilized to evaluate various types of biliary stent placement using ERCP, irrespective of types of stents and location of biliary stricture. In this article, we review the TOKYO criteria as a standardized reporting system for endoscopically-placed biliary stents. We also discuss potential controversial issues in the application of the TOKYO criteria. Given that endoscopic ultrasound-guided biliary drainage is increasingly utilized for cases with failed ERCP or altered gastrointestinal anatomy, we further propose a potential application of the TOKYO criteria to reporting of outcomes of this procedure.
Cholangiopancreatography, Endoscopic Retrograde ; Cholangitis ; Common Bile Duct ; Constriction, Pathologic ; Drainage ; Endosonography ; Evidence-Based Medicine ; Hospitalization ; Jaundice, Obstructive ; Plastics ; Population Characteristics ; Recurrence ; Self Expandable Metallic Stents ; Stents

Afferent loop syndrome is often difficult to resolve. Among patients with afferent loop syndrome whose data were extracted from databases, 5 patients in whom metal stent placement was attempted were included and evaluated in this study. The procedure was technically successful without any adverse events in all patients. Metal stent(s) was placed with an endoscope in the through-the-scope manner in 4 patients and via a percutaneous route in 1 patient. Obvious clinical efficacy was observed in all patients. Adverse events related to the procedure and stent occlusion during the follow-up period were not observed. Metal stent placement for malignant obstruction of the afferent loop was found to be safe and feasible.
Afferent Loop Syndrome ; Endoscopes ; Follow-Up Studies ; Humans ; Intestinal Obstruction ; Palliative Care ; Self Expandable Metallic Stents ; Stents* ; Treatment Outcome

BACKGROUND/AIMS: Dysphagia is encountered in a large proportion of patients with lung cancer and is associated with malnutrition and a poor quality of life. This study compared the clinical outcomes of self-expandable metallic stent (SEMS) insertion and percutaneous gastrostomy (PG) feeding for patients with lung cancer and dysphagia. METHODS: A total of 261 patients with lung cancer, who underwent either SEMS insertion (stent group) or PG (gastrostomy group) as an initial treatment procedure for dysphagia between July 1997 and July 2015 at the Samsung Medical Center, were reviewed retrospectively, and 84 patients with esophageal obstruction were identified. The clinical outcomes, including the overall survival, additional intervention, complications, and post-procedural nutritional status in the two groups, were compared. RESULTS: Among the 84 patients finally analyzed, 68 patients received SEMS insertion and 16 had PG. The stent group had less cervical obstruction and more mid-esophageal obstruction than the gastrostomy group. The Kaplan-Meier curves revealed similar overall survival in the two groups. Multivariate analysis showed that the two modalities had similar survival rates (PG compared with SEMS insertion, hazard ratio 0.682, p=0.219). Fifteen patients (22.1%) in the stent group received additional intervention, whereas there was no case in the gastrostomy group (p=0.063). The decrease in the serum albumin level after the procedure was lower in the gastrostomy group than in the stent group (-0.20±0.54 g/dL vs. -0.65±0.57 g/dL, p=0.013) CONCLUSIONS: SEMS insertion and PG feeding for relieving dysphagia by lung cancer had a comparable survival outcome. On the other hand, PG was associated with a better nutritional status.
Deglutition Disorders* ; Esophageal Stenosis ; Gastrostomy* ; Hand ; Humans ; Lung Neoplasms* ; Lung* ; Malnutrition ; Multivariate Analysis ; Nutritional Status ; Quality of Life ; Retrospective Studies ; Self Expandable Metallic Stents ; Serum Albumin ; Stents* ; Survival Rate

PURPOSE: The endoscopic management of a fully covered self-expandable metal stent (SEMS) has been suggested for the primary treatment of patients with anastomotic leaks after total gastrectomy. Embedded stents due to tissue ingrowth and migration are the main obstacles in endoscopic stent management. MATERIALS AND METHODS: The effectiveness and safety of endoscopic management were evaluated for anastomotic leaks when using a benign fully covered SEMS with an anchoring thread and thick silicone covering the membrane to prevent stent embedding and migration. We retrospectively reviewed the data of 14 consecutive patients with gastric cancer and anastomotic leaks after total gastrectomy treated from January 2009 to December 2016. RESULTS: The technical success rate of endoscopic stent replacement was 100%, and the rate of complete leaks closure was 85.7% (n=12). The mean size of leaks was 13.1 mm (range, 3–30 mm). The time interval from operation to stent replacement was 10.7 days (range, 3–35 days) and the interval from stent replacement to extraction was 32.3 days (range, 18–49 days). The complication rate was 14.1%, and included a single jejunal ulcer and delayed stricture at the site of leakage. No embedded stent or migration occurred. Two patients died due to progression of pneumonia and septic shock 2 weeks after stent replacement. CONCLUSIONS: A benign fully covered SEMS with an anchoring thread and thick membrane is an effective and safe stent in patients with anastomotic leaks after total gastrectomy. The novelty of this stent is that it provides complete prevention of stent migration and embedding, compared with conventional fully covered SEMS.
Anastomotic Leak* ; Constriction, Pathologic ; Gastrectomy* ; Humans ; Membranes* ; Pneumonia ; Retrospective Studies ; Self Expandable Metallic Stents ; Shock, Septic ; Silicon ; Silicones ; Stents* ; Stomach Neoplasms ; Ulcer