Academic literature on the topic 'Metallic stents'
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Journal articles on the topic "Metallic stents"
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Hanai, Takahiro, Takashi Kawahara, Hiroaki Ishida, Shinnosuke Kuroda, Toshitaka Miyai, Masato Yasui, Shuntaro Aoki, and Hiroji Uemura. "Bilateral Encrusted Metallic Stent Successfully Removed by Ureteroscopic Lithotripsy Using a Ho:YAG Laser in a Patient with Malignant Myeloma." Case Reports in Oncology 13, no. 3 (December 17, 2020): 1501–5. http://dx.doi.org/10.1159/000511601.
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Ureteral stent encrustation is sometimes encountered, especially in cases in which a ureteral stent has been forgotten. An 84-year-old female patient with malignant myeloma underwent metallic ureteral stent insertion to treat malignant ureteral obstruction. At the time of scheduled ureteral stent exchange, the stent was heavily encrusted and could not be removed on either side. We performed endoscopic lithotripsy to remove the encrusted ureteral stents. The bilaterally encrusted metallic ureteral stents were successfully removed using Ho:YAG laser lithotripsy after inserting another ureteral stent placement besides the encrusted metallic ureteral stents.
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Tsuboi, Tomofumi, Tamito Sasaki, Masahiro Serikawa, Yasutaka Ishii, Teruo Mouri, Akinori Shimizu, Keisuke Kurihara, et al. "Preoperative Biliary Drainage in Cases of Borderline Resectable Pancreatic Cancer Treated with Neoadjuvant Chemotherapy and Surgery." Gastroenterology Research and Practice 2016 (2016): 1–6. http://dx.doi.org/10.1155/2016/7968201.
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Objective. To elucidate the optimum preoperative biliary drainage method for patients with pancreatic cancer treated with neoadjuvant chemotherapy (NAC).Material and Methods. From January 2010 through December 2014, 20 patients with borderline resectable pancreatic cancer underwent preoperative biliary drainage and NAC with a plastic or metallic stent and received NAC at Hiroshima University Hospital. We retrospectively analyzed delayed NAC and complication rates due to biliary drainage, effect of stent type on perioperative factors, and hospitalization costs from diagnosis to surgery.Results. There were 11 cases of preoperative biliary drainage with plastic stents and nine metallic stents. The median age was 64.5 years; delayed NAC occurred in 9 cases with plastic stent and 1 case with metallic stent (p=0.01). The complication rates due to biliary drainage were 0% (0/9) with metallic stents and 72.7% (8/11) with plastic stents (p=0.01). Cumulative rates of complications determined with the Kaplan-Meier method on day 90 were 60% with plastic stents and 0% with metallic stents (log-rank test,p=0.012). There were no significant differences between group in perioperative factors or hospitalization costs from diagnosis to surgery.Conclusions. Metallic stent implantation may be effective for preoperative biliary drainage for pancreatic cancer treated with NAC.
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Brown, James A., Christopher L. Powell, and Kristopher R. Carlson. "Metallic Full-Length Ureteral Stents: Does Urinary Tract Infection Cause Obstruction?" Scientific World JOURNAL 10 (2010): 1566–73. http://dx.doi.org/10.1100/tsw.2010.162.
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Metallic ureteral stents promise to offer superior upper urinary tract drainage with extended exchange intervals and freedom from extrinsic compression in patients with advanced malignancy or other significant obstructing retroperitoneal or pelvic processes. Existing literature indicates a variable experience with these relatively new devices, with some investigators reporting excellent results and long problem-free intervals, and others reporting less enthusiastic outcomes. We report a retrospective review of a series of five sequential patients undergoing placement of Resonance® (Cook Medical, Bloomington, IN) metallic ureteral stents for extrinsic ureteral compression refractory to placement of traditional (polymer) ureteral stents. Of five patients reviewed, three (60%) required additional operative intervention for stent migration or malposition. Four patients (80%) died of their primary malignancy <12 months after metallic stent placement. Four (80%) of five patients had obstruction of their stents demonstrated with nuclear renography and/or other imaging, and three (60%) required removal and alternative means of urinary tract drainage within 4 months of placement due to obstruction, intractable pain, or migration. Four patients (80%) had urinary tract infections (UTIs) within 4 months of stent placement. No obstruction was seen due to extrinsic ureteral compression after stent placement. Metallic ureteral stents may have utility for patients with pathological processes causing extrinsic ureteral compression refractory to the use of traditional polymer ureteral stents. However, metallic ureteral stents are not immune to obstruction, migration, and associated discomfort. Stent obstruction appears to be increased in patients with postoperative UTI.
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Rasmussen, I. C., U. Dahlstrand, G. Sandblom, L. G. Eriksson, and R. Nyman. "Fractures of self-expanding metallic stents in periampullary malignant biliary obstruction." Acta Radiologica 50, no. 7 (September 2009): 730–37. http://dx.doi.org/10.1080/02841850903039763.
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Background: Self-expanding metallic stents are widely used for relieving biliary duct obstruction in patients with unresectable periampullary malignancies. However, only a few studies have assessed the occurrence of fractures in these stents. Purpose: To determine the prevalence and significance of stent fracture after placement of self-expanding metallic stents for periampullary malignant biliary obstruction. Material and Methods: Over a 5-year period, 48 patients underwent placement of self-expanding metallic stents for periampullary malignant biliary obstructions. Stents were introduced 2–6 weeks after a percutaneous transhepatic biliary decompression. The medical records and relevant images were reviewed for stent patency, stent fracture, type of stent, and stent-related complications. Results: Stent fracture was detected in four of the 48 patients (8%): in one patient at 1 month and in three patients between 10 and 21 months after stenting. All four fractures involved one type of nitinol stent used in 38 patients. In one of the patients, fracture was complicated by life-threatening gastrointestinal bleeding. The mean survival time for all patients was 251 days (standard deviation [SD]±275 days) and the mean overall patency time for all stents was 187 days (SD±205 days). Conclusion: Stent fracture occurs after placement of self-expanding nitinol stents for periampullary malignant biliary obstruction. The low reported incidence of this complication may be due to a lack of awareness of and difficulty in detecting stent fracture. Fracture should be considered as a possible contributing factor in recurrent biliary obstruction after self-expanding metallic stent insertion.
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Wang, Yanli, Pengfei Dong, Jingyao Ke, Xiang Shen, Zongming Li, Kewei Ren, Xinwei Han, and Linxia Gu. "Experimental evaluation of self-expandable metallic tracheobronchial stents." Nanotechnology Reviews 8, no. 1 (October 29, 2019): 136–42. http://dx.doi.org/10.1515/ntrev-2019-0013.
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Abstract The self-expandable metallic stents have been widely used in tracheobronchial obstruction or fistulation, including the J-shaped and Y-shaped stents, named after the shape of the branch-stem junction of the stent. However, there is scarce data on the mechanical performance of these tracheobronchial stents, which is essential for optimal stent implantation. In this work, eight self-expandable metallic tracheobronchial stents in three types (i.e., straight, J-shaped, and Y-shaped), with or without cover, were characterized. The compression resistance of the stems was investigated through both compression and indentation tests. The bending resistance of the branches in the J-shaped and Y-shaped stents was assessed through the bending test. Our results demonstrated that the covered stents exhibited a significantly higher compression resistance and bending resistance than the uncovered ones. The branches had a minimal impact on the compression resistance of the stem. The branch of the J-shaped stent showed a significantly lower bending resistance than the Y shaped one. This work provides a testing framework for the J-shaped and Y-shaped stents,which could shed some light on the optimal design of stent with branches.
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Cwikiel, W., H. Stridbeck, and U. Stenram. "Electrolytic Stents to Inhibit Tumor Growth." Acta Radiologica 34, no. 3 (May 1993): 258–62. http://dx.doi.org/10.1177/028418519303400311.
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Obstruction of metallic stents used in the management of malignant biliary strictures is common and in several cases due to tumor growth through the stent wall. In an experimental animal model in rats, a tumor was implanted subcutaneously adjacent to different metallic stents. Ingrowth of tumor through the wall of these stents was frequent. A stent generating direct electric current on the basis of electrolysis was developed and tested in vitro and in the experimental model. The study confirms that an “electrolytic” stent can inhibit ingrowth of tumor.
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Cwikiel, Wojciech, Krasnodar Ivancev, and Anders Lunderquist. "Metallic Stents." Radiologic Clinics of North America 28, no. 6 (November 1990): 1203–10. http://dx.doi.org/10.1016/s0033-8389(22)02661-6.
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Newton, Mark R., and James A. Brown. "Full-Length Metallic Double J Stents: A Review of Resonance® Stents." Clinical Medicine Insights: Urology 5 (January 2011): CMU.S6604. http://dx.doi.org/10.4137/cmu.s6604.
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Ureteral stricture, regardless of etiology, remains difficult to treat. Mainstays of therapy include polymeric double J stents and percutaneous nephrostomy tubes, each with respective complications. Multiple retrospective studies have now been published using the Resonance metallic double J stent, which is the focus of this review. A literature search was completed utilizing Pub Med. Key words included metallic stent, Resonance stents, and ureteral stricture. All identified papers were included. The stent is generally well tolerated, with infections, hematuria, and voiding symptoms requiring removal in 0% –14% of patients. Stents remained in place for mean of 4 to 9.4 months with the exception of a single study evaluating ureteroenteric strictures, where average duration was 21 days. In most studies a subset of patients kept the stent in situ for > 12 months, indicating that for some, the Resonance stent is a viable option, though predicting which patients will do well remains difficult.
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Shah, Jimil, and Surinder Singh Rana. "Newer Stents for Unresectable Malignant Distal Biliary Obstruction: Striving for Perfection!" Journal of Digestive Endoscopy 12, no. 01 (March 2021): 059–62. http://dx.doi.org/10.1055/s-0041-1728841.
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AbstractEndoscopic biliary stenting is one of the most commonly used palliative procedure in patients with unresectable malignant distal biliary obstruction. Biliary stenting can be performed with either plastic or metallic stents. Stent occlusion and migration are important limitations of currently available stents. Variety of newer stents with varying designs and stent materials like stents with antimigratory properties, antireflux stents, drug-eluting stents, radioactive stents, and bioabsorbable stents are being developed to overcome the limitations of currently available stents. In this article, we are discussing two articles on the newer stent designs (plastic and metal stents) for biliary drainage in patients with unresectable malignant distal biliary obstruction.
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Mladenovic, A., K. Davidovic, B. Markovic, P. Anojcic, M. Stojadinovic, and H. Maksimovic. "Stricture recanalisation of the distal urether with various endoprothesis." Acta chirurgica Iugoslavica 57, no. 2 (2010): 61–64. http://dx.doi.org/10.2298/aci1002061m.
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Introduction: Application of the metallic stents in the interventional uroradioligy is the result of continuous development of the new generation methods percutaneous nephrostomy (PCN), ballon catheter dilatation (BCD), methal and covered stent application. Application of metal stents in the renal canal system was attempted in order to eliminate BCD and PCN - related limitations as well as poor therapeutic results of these methods in a number of etiopathogenic groups of urinary stasis. Years - long application of interventional uroradiology methods, until the development of metallic stengts had shown the following therapeutics facts: PCN is incapable to resolve the cause of urinary obstruction. Permanent good therapeutic BCD results mostly depend on pathohistological aspect of the stricture, metallic stents are most frequently the last choice in therapeutics approch to urinary tract obstructions and their application is directly dependent on previous therapeutics results accomplished by PCN and BCD. In therapeutical sequences new generation of covered stents have important place as method of selection in patients of irreversible uroopstruction of distal ureter. Objective: The main goal of this study was to analyze therapeutics results, advanteges and shortages of insercion plastics and opened metallic endoprothesis, and to analyze results of covered methal applications on the contrary of using older interventional uroradiology methods. Method: Sixthytwo patients with distal urether strictures threated in the Deparment of interventional uroradiology Institute of Radiology Clinical centre of Serbia in Belgrade, participated in the study. Results were analyzed with Person's 2- test, Fisher test and Student T-test. Results: In our study we had highly significant differences in comparison with number of patients and type of stents during the time after recanalization was reached. Also it was highly significant differences according the type of used interventional uroradiology method that treated proliferation and the success of recanalization. Conclusion: Application of covered temporary uretheral stents have number advantages against using generation older permanent methal endoprothesis.
Dissertations / Theses on the topic "Metallic stents"
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AL-Mangour, Bandar. "The use of cold sprayed alloys for metallic stents." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=107900.
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With the invention of the coronary stent, which is a wire metal mesh tube designed to keep the arteries open in the treatment of heart diseases, promising clinical outcomes were generated. However, the long term successes of stents have been delayed by significant in-stent restenosis (blockages) and stent fracture. In this research work, it has been proposed to use Cold Gas Dynamic Spraying (CGDS) coating material as an alternative choice to manufacture metallic stent. In CGDS, fine particles are accelerated to a high velocity and undergo solid-state plastic deformation upon impact on the substrate, which leads to particle-particle bonding. The feature of CGDS distinct from other thermal spray techniques is that the processing gas temperature is below the melting point of the feedstock. Therefore, unwanted effects of high temperatures, such as oxidation, grain growth and thermal stresses, are absent. In response to the fact that the majority of stents are made from stainless steel (316L) or Co-Cr alloy (L605), this study specifically addresses the development and characterization of 316L and 316L mixed with L605 coatings produced by the CGDS process. Scanning electron microscopy and electron backscatter diffraction were used to investigate the microstructural changes of these coatings before and after annealing. The effect of gas type on the microstructure of 316L coatings and the role of post-heat treatment in the microstructure and properties are also studied. Of particular interest are grain refinement, heat treatment, mechanical properties and corrosion behavior of the cold sprayed material.L'invention du stent coronaire, est un tube en treillis métallique conçu pour maintenir les artères ouvertes dans le traitement des maladies cardiovasculaires. Des résultats cliniques prometteurs ont été rapportés. Cependant, le succès à long terme des stents est problématique à cause des resténoses intra-stent et des fractures de stent par fatigue. Dans ce travail de recherche, il est proposé d'utiliser la technologie de pulvérisation dynamique des gaz à froid (CGDS) comme une alternative pour la fabrication de stents métalliques. En CGDS, de fines particules sont accélérées avec une vitesse élevée et subissent une déformation plastique à l'impact sur un substrat. La particularité du CGDS parmi les autres techniques de pulvérisation thermique est que la température des gaz dans le processus est bien en dessous du point de fusion de la matière. Par conséquent, les effets indésirables des températures élevées, telles que l'oxydation, la croissance du grain et les contraintes thermiques, sont absents. Comme la majorité des stents sont faits en acier inoxydable 316L et en alliage Co-Cr, cette étude porte spécifiquement sur le développement et la caractérisation de l'acier inoxydable et l'acier inoxydable 316L mélangé avec revêtements d'alliages Co-Cr produite par le procédé CGDS. Les techniques de microscopie électronique à balayage et à diffraction d'électrons rétrodiffusés ont été utilisées pour étudier les changements de microstructures de ces revêtements avant et après recuit. L'effet du type de gaz sur la microstructure des revêtements 316L et le rôle du post-traitement thermique à froid par pulvérisation dans la microstructure et les propriétés mécaniques et électrochimiques ont été également étudiées.
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Mousselli, Jad. "On surface electropolishing for the development of metallic stents." Master's thesis, Université Laval, 2019. http://hdl.handle.net/20.500.11794/36574.
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Les maladies cardiovasculaires sont responsables d'environ le tiers de tous les cas de décès au Canada. L'une des solutions utilisées pour résoudre ce problème consiste à utiliser un dispositif métallique constitué d'un maillage ayant une forme d’un filet et appelé stent. Les stents sont de petits dispositifs implantés dans des vaisseaux sanguins rétrécis pour rétablir la circulation sanguine et éviter une crise cardiaque ou un accident vasculaire cérébral et pour traiter les anévrismes du cerveau. Un contrôle précis de la surface de ces stents est nécessaire pour assurer la compatibilité de l'alliage choisi avec le milieu biologique dont il va être en contact avec. Les stents métalliques doivent satisfaire à des conditions précises définies en fonction de leur application finale. Ils doivent respecter des exigences strictes en termes de propriétés mécaniques, d'interaction électrochimique (corrosion) et de cytocompatibilité. Les alliages suivants sont traditionnellement utilisés dans les applications biomédicales et plus précisément pour les applications cardiovasculaires: l'alliage AISI316L est considéré comme une référence dans ce domaine, mais l'alliage L605, un alliage à base de Cobalt, prend de plus en plus d'importance grâce à ses propriétés mécaniques élevées (haute ductilité et haute résistance à la traction) et résistance élevée à la corrosion. L'utilisation d'alliages de titane est la nouvelle frontière pour les biomatériaux dans les applications cardiovasculaires, il est considéré comme un nouveau candidat potentiel pour les stents cardiovasculaires. Les alliages de titane présentent une combinaison unique de haute résistance et de grande ductilité (résistance à la traction et déformation uniforme supérieures à 1000 MPa et 30% respectivement). L’électropolissage est une étape de prétraitement appliquée à ces alliages métalliques pour obtenir des surfaces chimiquement homogènes, recouvertes d'une couche d'oxyde uniforme et amorphe, généralement de rugosité très lisse. Ce processus permet non seulement de contrôler les propriétés physiques de la surface, mais également celles chimiques. Le processus d'électropolissage comporte certaines variables, telles que le courant, la tension, la solution électrolytique et la température de l'électrolyte. En les contrôlant, il est possible de comprendre et d'améliorer les propriétés de la surface. Le but de ce projet est d’étudier les effets des différents variables d’électropolissage (courant, tension, solution électrolytique) sur les caractéristiques / propriétés de surface (morphologie, composition chimique et mouillabilité) des alliages utilisés pour la fabrication de stents.Cardiovascular diseases (CVD) are responsible for about one-third of all death cases in Canada. One of the solutions used to solve this problem is using a metallic device made of a mesh and called a stent. Stents are small devices that are implanted in narrowed blood vessels to restore blood flow and to avoid a heart attack or stroke and to treat brain aneurysms. An accurate surface control is needed to assure the cytocompatibility of the chosen alloy with its biologic environment. Metallic stents must satisfy precise conditions defined according to their final application. They need to respect strict requirements, in terms of mechanical properties, electrochemical interaction (corrosion) and cytocompatibility. The following alloys are traditionally used in biomedical applications and more precisely for cardiovascular applications: the alloy AISI316L is considered a reference in this field, but the alloy L605, a Co-based material, is gaining more and more importance, due to its high mechanical properties (high ductility and high ultimate tensile strength) and high corrosion resistance. The use of Titanium alloys is the new frontier for biomaterials in cardiovascular applications, it is considered as a new potential candidate for cardiovascular stents. Titanium alloys, shows a unique combination of high strength and high ductility (ultimate tensile strength and uniform deformation higher than 1000 MPa and 30%, respectively). Electropolishing is a pre-treatment step applied to these alloys to obtain chemically homogeneous surfaces, covered with a uniform and amorphous oxide layer, generally with a very smooth roughness. This process not only makes it possible to control the physical properties of the surface, but also the chemical ones. The electropolishing process has some changeable variables, such as current, voltage, electrolytic solution and temperature of electrolyte. By controlling them, it is possible to understand and improve the surface properties. This work is aimed at studying the effects of electropolishing changeable variables (current, voltage, electrolytic solution) on surface characteristics/properties (morphology, chemical composition and wettability) of those alloys used for the manufacture of stents.
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Halwani, Dina. "Metal-tissue interactions in early stage biocorrosion of metallic stents." Birmingham, Ala. : University of Alabama at Birmingham, 2007. https://www.mhsl.uab.edu/dt/2007m/halwani.pdf.
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Thesis (M.S.)--University of Alabama at Birmingham, 2007.Additional advisors: Peter G. Anderson, Brigitta C. Brott, Jack E. Lemons. Description based on contents viewed Feb. 4, 2008; title from title screen. Includes bibliographical references (p. 69-70).
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Oikarinen, H. (Heljä). "Imaging of biliary carcinoma, fistula and primary sclerosing cholangitis and percutaneous metallic stenting in malignant biliary obstruction." Doctoral thesis, University of Oulu, 2001. http://urn.fi/urn:isbn:9514259173.
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Abstract
Biliary carcinoma, biliary fistula with occasional gallstone ileus and primary sclerosing cholangitis (PSC) are serious
diseases and present specific diagnostic and therapeutic challenges. Stenting of biliary obstruction has also involved
problems, but the reports are contradictory and partly limited. The aim of the present work was to evaluate and compare
various imaging modalities in biliary diseases. The study also aimed to evaluate the usefulness of metallic stents in
malignant biliary obstruction.
The study population consisted of 210 patients with gallbladder carcinoma, bile duct carcinoma, biliary fistula, PSC or
malignant biliary obstruction and eight control patients with various hepatobiliary diseases. The imaging findings of 80
patients with gallbladder carcinoma, 58 patients with bile duct carcinoma, and 16 patients with biliary fistula were
reviewed. Nine patients with PSC underwent magnetic resonance cholangiography (MRC) and magnetic resonance imaging (MRI) of
the liver, ultrasonography (US) of the liver and the bile ducts and endoscopic retrograde cholangiography (ERC). Eight
control patients had had MRC and MRI of the liver and ERC. The medical records and radiographs of 39 patients with malignant
biliary obstruction treated with percutaneously inserted metallic stents were also analysed. The stents included 48
Wallstents and seven Memotherm stents.
In cases of gallbladder carcinoma, US visualised the primary tumour in 68 % and computed tomography (CT) in 57 % of the cases
examined, but both methods were insufficient for accurate staging. In bile duct carcinoma, US revealed the primary tumour in
63 % and CT in 44 % of the cases examined. Both methods were sensitive in diagnosing peripheral intrahepatic
cholangiocarcinoma, but inaccurate for more distal bile duct carcinoma or abdominal spread. The infiltrating type of
gallbladder carcinoma and bile duct carcinoma were difficult to detect. US and CT were sensitive in revealing bile duct
obstruction.
The patients with biliary fistula and gallstone ileus had undergone various examinations with pathological, but not
diagnostic results, and there was often a delay to diagnosis. Imaging did not reveal any of the ten spontaneous fistulas, but
CT showed one of the five cases of gallstone ileus, and Gastrografin® meal revealed the single case of Bouveret's
syndrome.
Fistulography or cholangiography revealed all but one of the six iatrogenic fistulas. A nonvisualised or shrunken gallbladder
at US should raise a suspicion of biliary enteric fistula in an appropriate clinical setting.
MRC-MRI depicted the changes of PSC correctly in nine patients (radiologist 1) and in eight patients with one false positive
finding (radiologist 2) in a blinded analysis. In the segmental comparison MRC missed especially bile duct dilatations. MRC
was too pessimistic in the evaluation of the predictors of poor outcome. US detected features suggestive of PSC in eight
patients (radiologist 3). US was unable to indicate the predictors of poor outcome.
Of the patients with metallic stents in malignant biliary obstruction, 30 % had early and 66 % late complications, including
stent obstructions, which occurred in 27 % of the patients at a mean of 4.4 months. The cause was mostly tumour ingrowth or
overgrowth. The 25-week and 50-week patency rates were 71 % and 42 %. The patency rates of the patients with
cholangiocarcinoma were significantly the lowest. There was also a tendency towards lower patency with less dilatation of the
stents, an increasing number of the stents, longer strictures and hilar strictures. Many other complications were infectious.
31 % of the patients had late reinterventions.
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Dorri, Megan Mahrokh. "Study for the optimization of interfacial properties between metallic substrates and polymeric coatings by plasma-based surface modification methods to improve performance of vascular stents." Doctoral thesis, Université Laval, 2017. http://hdl.handle.net/20.500.11794/28229.
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Au cours de 15 dernières années, les maladies coronariennes et les accidents vasculaires cérébraux demeurent les causes principales de décès dans le monde. Selon l'Organisation Mondiale de la Santé, en 2015, ces deux maladies ont causé 15 millions des décès sur les 56,4 millions dans le monde. Des traitements chirurgicaux ont été élaborés et améliorés pour soigner ces maladies en maintenant les vaisseaux sanguins ouverts. Parmi les traitements chirurgicaux, l'angioplastie avec utilisation d’un stent est le traitement le plus populaire et le moins invasif. Les stents, qui sont des tubes métalliques en treillis, vont soutenir mécaniquement les vaisseaux sanguins après l’implantation et les maintenir ouverts pour améliorer le flux sanguin. Ceux-ci sont principalement composés d’acier inoxydable AISI316L (SS316L), d'alliage de cobalt-chrome et d'alliage de titane. Depuis plus d'un demi-siècle, lorsqu'un stent a été implanté pour la première fois, ils ont été considérablement améliorés. Cependant, la libération d'ions métalliques, potentiellement toxiques, et la détérioration des propriétés mécaniques à cause de la corrosion ainsi que la diminution de l'adhérence des revêtements, dans le cas de stents avec les revêtements en polymère, constituent encore des préoccupations majeures lors de l’utilisation des stents. Dans le cas des stents en SS316L, afin d’éviter la libération d'ions métalliques, au laboratoire de biomatériaux et de bioingénierie de l'Université Laval (LBB), lors de précédentes recherches, un revêtement fluorocarboné (CFx) a été étudié pour isoler complètement le stent de l'environnement biologique. Ce revêtement permet également le greffage ultérieur de molécules bioactives pour améliorer son intégration dans le corps. Cependant, l'interface de SS316L / CFx devait être améliorée pour augmenter l’adhésion du revêtement CFx sur le SS316L. Dans mon projet de doctorat, l’oxydation au plasma a été utilisé pour élaborer une nouvelle interface entre le substrat SS316L et le revêtement. Les propriétés de cette nouvelle interface, qui est composée d’une couche d'oxyde, ont été modifiées en faisant varier les paramètres du procédé plasma afin de préserver les propriétés de cette couche d’oxyde lorsqu’elle subit une déformation plastique de 25%, c’est-à-dire le pourcentage de déformation maximale que subira le stent lors de son implantation. Cette interface a permis de diminuer la libération des ions du substrat SS316L en réduisant son taux de corrosion plus que trois fois et d’améliorer l’adhérence adéquate du revêtement CFx sur le substrat, après déformation et après immersion dans une solution aqueuse saline. La nouvelle couche d'oxyde sur SS316L est une couche d'oxyde amorphe avec une épaisseur d'environ 6 nm qui se distincte bien de la microstructure polycristalline du substrat. L'amélioration des propriétés de l'interface a été attribuée à cette couche d'oxyde amorphe nano-épaisse, qui est résistante aux déformations plastiques. Cette couche d'oxyde peut être appliquée sur des stents métalliques nus composés de métaux passivables. En outre, elle crée une interface favorable pour les revêtements en polymère, qui sont utilisés pour les stents à relargage de principes actifs ainsi que pour améliorer l'intégration des stents dans le corps humain.Over the past 15 years, ischemic heart disease and stroke have remained the leading causes of death, worldwide. According to the World Health Organization, 15 million of the 56.4 million global deaths, in 2015, were caused only by ischemic heart disease or stroke. For the treatment of these diseases, surgical treatments have been introduced and improved to hold the blood vessels open. Among the surgical treatments, angioplasty with stenting is the most popular and the least invasive treatments. Stents, which are wire mesh tubes, prepare a mechanical support for blood vessels and hold them open to restore the blood flow. They are mostly made up of AISI316L stainless steel (SS316L), cobalt-chromium, and titanium alloys. More than half a century ago, when a stent first used, it has considerably evolved. However, release of potentially-toxic metallic ions and deterioration of mechanical properties due to corrosion, and decrease of polymeric coatings adhesion, in case of coated stents, still constitute major concerns in SS316L stents. In the case of SS316L stents, to circumvent the release of metallic ions, in the laboratory for biomaterials and bioengineering of Université Laval (LBB), a fluorocarbon (CFx) coating was previously investigated to isolate the stent completely from the biological environment. The coating also enables subsequent grafting of bioactive molecules to improve its integration in the body. The results were promising; however, the interface of SS316L/CFx needed to be modified to improve the adhesion of the CFx coating. In this Ph.D. research project, a new interface between the SS316L substrate and the CFx coating was created by plasma oxidation. The properties of this new interface, which was an oxide layer, was modified by varying the plasma-process parameters in order to preserve its properties after a 25% plastic deformation. This deformation is the maximum plastic deformation that imposes on a stent during its implantation. The new interface decreased the release of ions by decreasing the corrosion rate of the SS316L substrate by a factor of three. It was also found that the new interface produced an adequate adhesion of the CFx coating to the substrate after deformation as well as after immersion in an aqueous saline solution. The new oxide layer on SS316L was an amorphous oxide layer with an approximately 6 nm thickness, which was clearly distinguished from the polycrystalline microstructure of the substrate. The enhancement of the interface properties was ascribed to this nano-thick amorphous oxide layer, which was found to be more resistant to plastic deformation. This new oxide layer can be produced on bare-metal stents made of passivating metals. Moreover, it can create a favorable interface for coated stents, which have been used in drug-eluting stents, and also to improve stents integration in the human body.
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Sullivan, J. H. "Metallic runoff from coated steels." Thesis, Swansea University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.639132.
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An investigation was carried out to assess levels of metallic runoff, particularly zinc, from the surface and cut-edges of a variety of commercial coated steels in order to ascertain potential environmental effects in line with the ongoing EU risk assessment into zinc (1995). Zinc runoff was monitored from the surfaces of a range of zinc-coated steels with sealed edges over 19 months at two UK weathering sites. The composition of the zinc coating is crucial in determining materials performance and rainfall levels are critical in determining runoff quantity. Observed zinc runoff levels are generally below the permissible drinking water level for humans but runoff levels in the harshest environment exceed this maximum for some materials during the exposure. A range of organically coated galvanised steels were exposed for 27 months at three UK weathering sites with a large cut-edge length to assess runoff from such edges. Runoff was high in initial months with zinc levels reducing with time due to the build up/action of corrosion products and corrosion inhibitors. Zinc levels were below the permissible drinking water level. Zinc runoff measured over 3 months can more accurately predict long-term organic coating delamination than salt spray and prohesion testing. Accelerated laboratory tests using a distilled water electrolyte were developed that predict long-term external weathering runoff from panels of a range of coated steels. The angle of panel, electrolyte flow rate and wet/dry cycles affect the runoff levels of such tests. The corrosion mechanisms of a variety of zinc-coated steels have been examined using the scanning vibrating electrode technique (SVET) in 0.1%NaCl. The corrosion behaviour of a coating is related to its structure and composition. The SVET has been used to assess total zinc loss from coatings during corrosion and has been confirmed using ICP-MS analysis. The predicted zinc losses from the SVET were used to model up to 12 months external weathering behaviour for the zinc-coated steels.
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Minata, Mauricio Kazuyoshi. "Próteses metálicas ou gastrojejunoanastomose no tratamento paliativo da obstrução gastroduodenal: revisão sistemática e metanálise." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/5/5168/tde-28092018-115210/.
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Introdução: obstrução gastroduodenal maligna é uma condição frequente em neoplasias gástricas e pancreáticas em estágio avançado. O tratamento paliativo visa a melhora dos sintomas e da qualidade de vida, sendo realizado pelas técnicas cirúrgicas ou endoscópicas. Embora a terapêutica cirúrgica seja consagrada, as complicações relacionadas ao procedimento e as condições clínicas desfavoráveis dos pacientes devem ser consideradas. Apesar dos avanços do tratamento endoscópico e da possibilidade de oferecer um tratamento menos invasivo, deve-se considerar as complicações e a taxa de reintervenção desta modalidade terapêutica. Novas tecnologias foram desenvolvidas para minimizar as complicações relacionadas ao uso de próteses e demandam uma análise pormenorizada. O objetivo desta revisão sistemática é comparar o tratamento endoscópico com próteses cobertas e não cobertas e o cirúrgico com gastrojejunoanastomose para obstrução gastroduodenal. Métodos: ensaios clínicos randomizados foram identificados nas bases de dados do MEDLINE, Embase, Cochrane, LILACS, SCOPUS e CINAHL. A comparação entre as próteses metálicas cobertas e não cobertas incluiu o sucesso técnico, sucesso clínico, complicações, obstrução, migração, sangramento, perfuração, fratura das próteses e reintervenção. Os desfechos usados na comparação da terapêutica cirúrgica com gastrojejunoanastomose e endoscópica com próteses foram o sucesso técnico, complicações e reintervenção. A avaliação da patência não pode ser incluída devido à falta de uniformidade dos dados extraídos. Resultados: oito artigos foram selecionados, três comparando gastrojejunostomia e próteses e cinco comparando próteses cobertas e não cobertas. A metanálise dos estudos sobre gastroenteroanastomose e próteses não demonstrou diferença significativa no sucesso técnico e número absoluto de complicações. O tratamento com próteses apresentou uma maior taxa de reintervenção que a terapêutica cirúrgica (DR = 0,26, IC 95% = 0,05 a 0,47, NNH = 4). A metanálise que comparou próteses metálicas cobertas e não cobertas não demonstrou diferença estatística significativa considerando o sucesso técnico, sucesso clínico, complicações, fratura das próteses, perfuração, sangramento e necessidade de reintervenção. Uma maior taxa de migração foi atribuída à terapêutica com próteses cobertas (DR = 0,09, IC 95% = 0,04 a 0,14, NNH = 11). Entretanto, o tratamento com próteses cobertas apresenta menor taxa de obstrução em relação às não cobertas (DR = -0,21, IC 95% = -0,27 a -0,15, NNT = 5). Uma análise de subgrupo de estudos com próteses metálicas que incluíram apenas pacientes com câncer gástrico demonstrou resultado semelhante à metanálise com todos os artigos. Conclusões: o tratamento endoscópico paliativo da obstrução gastroduodenal maligna com próteses cobertas apresenta maior taxa de migração e menor número de obstruções quando comparado com o uso de próteses não cobertas. A terapêutica cirúrgica com gastrojejunoanastomose associa-se a uma menor taxa de reintervenção em relação ao uso de prótesesIntroduction: malignant gastric outlet obstruction is a frequent condition in advanced gastric and pancreatic neoplasms. Palliative treatment can be performed by endoscopic or surgical techniques. Palliation aims to relief symptoms and increase quality of life. Although surgical therapy is the established treatment, the complication rate of the procedure and the unfavorable clinical conditions must be considered. Despite the advances in the endoscopic treatment and the possibility to offer a minimally invasive therapy, complication rate and need of reintervention must be reminded. New technologies have been developed to minimize the complications related to the use of stents and require a detailed analysis. This systematic review aims to compare surgery and covered and uncovered stent treatments for gastric outlet obstruction. Methods: randomized clinical trials were identified in MEDLINE, Embase, Cochrane, LILACs, BVS, SCOPUS and CINAHL databases. Comparison of covered and uncovered stents included: technical success, clinical success, complications, obstruction, migration, bleeding, perforation, stent fracture and reintervention. The outcomes used to compare Gastrojejunostomy and stents were technical success, complications and reintervention. Patency rate could not be included because of lack of uniformity of the extracted data. Results: eight studies were selected, three comparing gastrojejunostomy and stents and five comparing covered and uncovered stents. The meta-analysis of surgical and endoscopic stent treatment showed no difference in the technical success and overall number of complications. Stents had higher reintervention rates than surgery (RD: 0.26, 95% CI [0.05, 0.47], NNH: 4). There is no significant difference in technical success, clinical success, complications, stent fractures, perforation, bleeding and the need for reintervention in the analyses of covered and uncovered stents. There is a higher migration rate in the covered stent therapy compared to uncovered self-expanding metallic stents in the palliation of malignant gastric outlet obstruction (RD: 0.09, 95% CI [0.04, 0.14], NNH: 11). Nevertheless, covered stents had lower obstruction rates (RD: -0.21, 95% CI [-0.27, - 0.15], NNT: 5). A subgroup analysis with studies that included only patients with gastric cancer showed similar results when compared with the analysis with all trials. Conclusions: in the palliation of malignant gastric outlet obstruction, covered stents had higher migration and lower obstruction rates when compared with uncovered stents. Gastrojejunostomy is associated with lower reintervention rates than stents
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KASAI, KENJI, SADAYUKI SAKUMA, SHIGEKI ITOH, HIROSHI FUKATSU, MITSUHIKO HIROSE, TSUNEO ISHIGUCHI, SANJAY S. BAIJAL, and SUMIT ROY. "Esophageal Stenting with a Self-expandable Metallic Device: A Preliminary Study." Nagoya University School of Medicine, 1992. http://hdl.handle.net/2237/17522.
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Brikas, Marijus. "Microprocessing of silicon and metals with high pulse repetition rate picosecond lasers." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2011. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2011~D_20110324_161348-78636.
Full textAbstract:
The objective of the thesis is to investigate applicability of high pulse repetition rate picosecond lasers for microfabrication and to clarify high repetition rate pulse interaction with metals and silicon.
The ablation threshold and accumulation rate dependence on the laser pulse duration for silicon and metals has been experimentally studied. The model of optimal focus conditions for the maximum ablation rate was developed and experimentally confirmed. The material evaporation rate decreases duo to plasma screening for high pulse energies.
Various pulse length lasers have been used for cutting and drilling of silicon.
In this work key properties of laser radiation, radiation absorption, ablation and plasma formation are discussed. Surface spectroscopy methods have shown that laser cutting of silicon in the air leads to the cut surface doping with carbon atoms up to 5 µm depth from carbon dioxide in the atmosphere, and the resulting silicon carbide influences the laser cut quality.
Testing of applicability of high pulse repetition rate picosecond lasers for the production of complex shapes, relationships between surface roughness and process parameters were determined. Heat abstraction from the workpiece, during laser cutting of stents from nitinol, limits the potential use of the average laser power and the effective cutting speed
The silver and gold picosecond laser ablation in the liquid medium generates a narrow size distribution of nanoparticles, which form a stable... [to full text]Disertacijos tikslas yra ištirti didelio impulsų pasikartojimo dažnio pikosekundinių lazerių pritaikomumą medžiagų mikroapdirbimui, bei išaiškinti tokių lazerių spinduliuotės sąveikos su metalais ir siliciu ypatybes. Eksperimentiškai buvo ištirta abliacijos slenksčio ir akumuliacijos koeficiento priklausomybė nuo lazerio impulso trukmės siliciui ir metalams. Sukurtas ir eksperimentiškai patvirtintas modelis optimalioms fokusavimo sąlygoms surasti, siekiant maksimalios abliacijos spartos. Didelei impulso energijai, medžiagos nugarinimo efektyvumas mažėja dėl ekranuojančio plazmos poveikio. Įvairių impulso trukmių lazeriai buvo panaudoti silicio gręžimui bei pjovimui. Paviršiaus spektroskopijos metodais, nustatyta, kad pjovimo metu silicis yra legiruojamas anglimi iki 5 µm gylio iš atmosferoje esančio anglies dvideginio, o susidariusi silicio karbido fazė įtakoja lazerinio pjovimo kokybę silicio bandinio gylyje. Taikant didelio impulsų pasikartojimo dažnio pikosekundinius lazerius sudėtingos formos detalių gamybai, rasti sąryšiai tarp paviršiaus šiurkštumo bei proceso parametrų. Pjaunant lazeriu stentus iš Nitinolio, šilumos nukreipimas nuo ruošinio riboja galimą panaudoti lazerio vidutinę galią ir tuo pačiu pasiekiamą efektyvųjį pjovimo greitį; Vykdant sidabro ir aukso abliaciją pikosekundiniu lazeriu skystyje, generuojamos siauro dydžių skirstinio nanodalelės, kurios sudaro stabilius koloidinius tirpalus.
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Brikas, Marijus. "Silicio ir metalų mikroapdirbimas didelio impulsų pasikartojimo dažnio pikosekundiniais lazeriais." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2011. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2011~D_20110324_161301-79480.
Full textAbstract:
Disertacijos tikslas yra ištirti didelio impulsų pasikartojimo dažnio pikosekundinių lazerių pritaikomumą medžiagų mikroapdirbimui, bei išaiškinti tokių lazerių spinduliuotės sąveikos su metalais ir siliciu ypatybes. Eksperimentiškai buvo ištirta abliacijos slenksčio ir akumuliacijos koeficiento priklausomybė nuo lazerio impulso trukmės siliciui ir metalams. Sukurtas ir eksperimentiškai patvirtintas modelis optimalioms fokusavimo sąlygoms surasti, siekiant maksimalios abliacijos spartos. Didelei impulso energijai, medžiagos nugarinimo efektyvumas mažėja dėl ekranuojančio plazmos poveikio. Įvairių impulso trukmių lazeriai buvo panaudoti silicio gręžimui bei pjovimui. Paviršiaus spektroskopijos metodais, nustatyta, kad pjovimo metu silicis yra legiruojamas anglimi iki 5 µm gylio iš atmosferoje esančio anglies dvideginio, o susidariusi silicio karbido fazė įtakoja lazerinio pjovimo kokybę silicio bandinio gylyje. Taikant didelio impulsų pasikartojimo dažnio pikosekundinius lazerius sudėtingos formos detalių gamybai, rasti sąryšiai tarp paviršiaus šiurkštumo bei proceso parametrų. Pjaunant lazeriu stentus iš Nitinolio, šilumos nukreipimas nuo ruošinio riboja galimą panaudoti lazerio vidutinę galią ir tuo pačiu pasiekiamą efektyvųjį pjovimo greitį; Vykdant sidabro ir aukso abliaciją pikosekundiniu lazeriu skystyje, generuojamos siauro dydžių skirstinio nanodalelės, kurios sudaro stabilius koloidinius tirpalus.The objective of the thesis is to investigate applicability of high pulse repetition rate picosecond lasers for microfabrication and to clarify high repetition rate pulse interaction with metals and silicon. The ablation threshold and accumulation rate dependence on the laser pulse duration for silicon and metals has been experimentally studied. The model of optimal focus conditions for the maximum ablation rate was developed and experimentally confirmed. The material evaporation rate decreases duo to plasma screening for high pulse energies. Various pulse length lasers have been used for cutting and drilling of silicon. In this work key properties of laser radiation, radiation absorption, ablation and plasma formation are discussed. Surface spectroscopy methods have shown that laser cutting of silicon in the air leads to the cut surface doping with carbon atoms up to 5 µm depth from carbon dioxide in the atmosphere, and the resulting silicon carbide influences the laser cut quality. Testing of applicability of high pulse repetition rate picosecond lasers for the production of complex shapes, relationships between surface roughness and process parameters were determined. Heat abstraction from the workpiece, during laser cutting of stents from nitinol, limits the potential use of the average laser power and the effective cutting speed The silver and gold picosecond laser ablation in the liquid medium generates a narrow size distribution of nanoparticles, which form a stable... [to full text]
Books on the topic "Metallic stents"
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Marcela, Selecká, and SpringerLink (Online service), eds. Manganese in Powder Metallurgy Steels. Cambridge: Cambridge International Science Publishing Ltd., 2012.
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Hill, Daryl Paul. The influence of non-metallic inclusions upon the properties of linepipe steels. Birmingham: Aston University. Department of Mechanical and Production Engineering, 1986.
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Berns, Hans. High Interstitial Stainless Austenitic Steels. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013.
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Sha, Wei. Steels: From Materials Science to Structural Engineering. London: Springer London, 2013.
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Textbook of Metallic Stents. Taylor & Francis, 1997.
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Sha, Wei. Steels. Springer, 2013.
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Berns, Hans, Valentin Gavriljuk, and Sascha Riedner. High Interstitial Stainless Austenitic Steels. Springer, 2012.
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Berns, Hans, Valentin Gavriljuk, and Sascha Riedner. High Interstitial Stainless Austenitic Steels. Springer, 2014.
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Durand-Charre, Madeleine. Microstructure of Steels and Cast Irons. Springer Berlin Heidelberg, 2010.
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Durand-Charre, Madeleine. Microstructure of Steels and Cast Irons. 2004.
Find full textBook chapters on the topic "Metallic stents"
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Rako, Duje. "Indications, Complications and Side Effects of Metallic Ureteral Stents." In Urinary Stents, 21–29. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-04484-7_3.
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AbstractFirst widely used ureteral stents were polymeric and first documented metallic stent placed in ureter was vascular permanent stent in patient with malignant obstruction. Due to high complication rates with off label bare metal stents and covered metal stents development of purpose-based urological metallic stents was started. They are nowadays usually exploited when longer indwelling times are envisioned due to benign conditions, malignant obstruction or post-radiotherapy. In our analysis we have witnessed high risk of complication—68% per patient and 50% per stent.Further research in form of multi-institutional prospective RCT in order to obtain better understanding of complications is needed which in turn can drive further development of stent materials, coatings and designs ultimately giving our patients better QoL.
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Brauer, H., V. Buck, and A. Fischer. "Mechanical Properties of Metallic Coronary Stents." In Materials for Medical Engineering, 172–78. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2005. http://dx.doi.org/10.1002/3527606149.ch24.
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Yachia, Daniel. "Learning from Our Mistakes: Applying Vascular Stent Technologies to the Urinary Tract." In Urinary Stents, 351–58. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-04484-7_28.
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AbstractThe aim of this chapter is to clarify certain points which are confusing many if not most of our urologist colleagues on the subject of “stents and stenting the urinary tract”. Another point of confusion in urology is the term of “chronic obstruction” describing an obstruction necessitating long-term stenting. Which stent to use? For how long? Before using a permanent stent along the urinary tract we should think hard about what may happen to a ureter or urethra implanted with a permanent metallic mesh stent. This is especially important when something goes wrong like when the stent lumen becomes obliterated by hyperplastic or malignant tissues, the stent wires fracture, or tissue coverage over the stent wires is incomplete and the resulting stone formation on the wires, ureteral or urethral perforations etc. By adopting the vascular stent technologies in urinary tract design stents, we were hoping that taking a single stent shape, changing its length and caliber they could be used all along the urinary tract. Then asking ourselves, why the results were less than what we were expecting. Here I would like to quote a sentence attributed to Albert Einstein: “Insanity is doing the same thing over and over again and expecting different results”.
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Soria, Federico, Julia E. de la Cruz, Marcos Cepeda, Álvaro Serrano, and Francisco M. Sánchez-Margallo. "Biodegradable Urinary Stents." In Urinary Stents, 359–73. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-04484-7_29.
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AbstractIn the twenty-first century, it is difficult to understand that a medical device as widely used as urinary stents require a second medical procedure for removal. Research in the development of biocompatible biodegradable urinary stents (BUS) has been one of the most important research areas of innovation in the urology stent technology. The main characteristics of a BUS are related to its ability to degrade into non-obstructive fragments in a predefined time and to be removed through micturition, after providing an appropriate internal scaffold effect and urinary drainage.One of the barriers slowing down the progress of research are the lack of agreement between in vitro and in vivo degradation rates demonstrated in a large number of experimental studies. Unfortunately, currently the absence of BUSs in clinical practice is mainly due to the complicated degradation rate control, maintenance of mechanical properties and safe urinary excretion of stent fragments. In order to alleviate the weak mechanical properties of degradable biomaterials, research has been started with metallic BUS with very promising results. In this regard, Mg2+ and its alloys have been used in in vitro and in vivo studies.Another area of current research is the emergence of ureteral BUS to provide a new approach for local drug delivery in upper urinary tract. Drugs may be released while the stent is degrading. Although these innovations are still under research, it is foreseeable that in the near future they could be used to improve the lives of patients.
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Filipović, Nenad, Nina Tomić, Maja Kuzmanović, and Magdalena M. Stevanović. "Nanoparticles. Potential for Use to Prevent Infections." In Urinary Stents, 325–39. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-04484-7_26.
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AbstractOne of the major issues related to medical devices and especially urinary stents are infections caused by different strains of bacteria and fungi, mainly in light of the recent rise in microbial resistance to existing antibiotics. Lately, it has been shown that nanomaterials could be superior alternatives to conventional antibiotics. Generally, nanoparticles are used for many applications in the biomedical field primarily due to the ability to adjust and control their physicochemical properties as well as their great reactivity due to the large surface-to-volume ratio. This has led to the formation of a new research field called nanomedicine which can be defined as the use of nanotechnology and nanomaterials in diagnostics, imaging, observing, prevention, control, and treatment of diseases. For example, coverings or coatings based on nanomaterials are now seen as a promising strategy for preventing or treating biofilms formation on healthcare kits, implants, and medical devices. Toxicity, inappropriate delivery, or degradation of conventionally used drugs for the treatment of infections may be avoided by using nanoparticles without or with encapsulated/immobilized active substances. Most of the materials which are used and examined for the preparation of the nanoparticles with encapsulated/immobilized active substances or smart reactive nanomaterials with antimicrobial effects are polymers, naturally derived antimicrobials, metal-based and non-metallic materials. This chapter provides an overview of the current state and future perspectives of the nanoparticle-based systems based on these materials for prevention, control, or elimination of biofilm-related infections on urinary stents. It also addresses manufacturing conditions indicating the huge potential for the improvement of existing and development of new promising stent solutions.
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Jaziri, Hiba, Sofiene Mokhtar, Khawla Aguir, and Saber Ben Abdessalem. "Investigation of PET-Braided Vascular Stents Potential Compared with Commercial Metallic Stents." In Narrow and Smart Textiles, 109–22. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-69050-6_10.
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Lammer, J. "Comparison of Various Types of Metallic Biliary Stents." In Biliary Tract Radiology, 381–86. Berlin, Heidelberg: Springer Berlin Heidelberg, 1997. http://dx.doi.org/10.1007/978-3-642-60343-3_30.
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Hermawan, Hendra, Maryam Moravej, Dominique Dubé, Michel Fiset, and Diego Mantovani. "Degradation Behaviour of Metallic Biomaterials for Degradable Stents." In THERMEC 2006 Supplement, 113–18. Stafa: Trans Tech Publications Ltd., 2006. http://dx.doi.org/10.4028/0-87849-429-4.113.
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Tiewala, Mustafa A., and Martin L. Freeman. "Self-Expanding Metallic Stents for Malignant Hilar Biliary Obstruction." In Self-Expandable Stents in the Gastrointestinal Tract, 217–33. New York, NY: Springer New York, 2012. http://dx.doi.org/10.1007/978-1-4614-3746-8_15.
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Rösch, Josef, Frederick S. Keller, and John A. Kaufman. "Expandable Metallic Stents in Management of Large Vein Obstructions." In PanVascular Medicine, 4539–48. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-642-37078-6_161.
Full textConference papers on the topic "Metallic stents"
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Grogan, J., S. Leen, and P. McHugh. "A Phenomenological Model of Corrosion in Biodegradable Metallic Stents." In ASME 2010 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2010. http://dx.doi.org/10.1115/sbc2010-19361.
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Coronary stents are tiny scaffolds that are used in the treatment of heart disease. A new generation of metallic stents that dissolve in the body when no longer required have shown promise in a number of clinical applications. However, one of the primary challenges in developing such a stent is maintaining adequate control over the rate at which it dissolves. A model that is capable of representing corrosion induced material degradation in a finite element framework is being developed. Such a model will prove useful in predicting the lifetime of biodegradable metallic stents in vivo.
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Shim, Chan Sup. "Role of metallic stents in benign esophageal stricture." In SPIE Nanosystems in Engineering + Medicine, edited by Sang H. Choi, Jin-Ho Choy, Uhn Lee, and Vijay K. Varadan. SPIE, 2012. http://dx.doi.org/10.1117/12.2004508.
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Halwani, Dina O., Peter G. Anderson, Brigitta C. Brott, Andreas S. Anayiotos, and Jack E. Lemons. "Corrosion of Metallic Endovascular Stents and Analyses of Wear Debris in Tissues." In ASME 2009 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2009. http://dx.doi.org/10.1115/sbc2009-206713.
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Corrosion resistance of metallic alloys commonly used in the manufacture of endovascular stents has been determined through in-vitro tests; however, limited information is available regarding the biostability of stent surfaces and their interaction with vascular tissue following implantation. As technology improves, stents are increasingly deployed in complex anatomy and higher risk locations. They are frequently implanted overlapping other stents, either deployed during the same procedure or to treat a recurrent lesion. In addition, with several alloys available for stents such as stainless steel (SS), nickel-titanium (NiTi), cobalt-chromium (CoCr), cobalt-chromium with a tantalum core (CoCr-Ta) and tantalum (Ta); there is an increasing likelihood of overlapping stents of different materials.
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Debusschere, Nic, Matthieu De Beule, Patrick Segers, Benedict Verhegghe, and Peter Dubruel. "Modeling of Coated Biodegradable Stents." In ASME 2012 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/sbc2012-80425.
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A bioresorbable stent supports the stenosed blood vessel during the healing period after coronary angioplasty and then gradually disappears. Unlike permanent stents, the biodegradable stent forms no obstacle for future interventions. Moreover, the degradable stent material presents an ideal vehicle for local drug delivery. Long term side effects inherent to drug eluting stents such as in-stent restenosis and late stent thrombosis might be avoided [1]. To date, several bioresorbable stents are being developed or are currently being tested in clinical trials. Two classes of biomaterials are being used in biodegradable stent technology: biodegradable polymers and bioerodible metal alloys. Polymers can be tailored to have a well-defined degradational behaviour but have relatively poor mechanical properties. Biocorrodible metals such as magnesium alloys have good mechanical characteristics but display a more complex an less predictive degradational behaviour. A biocorrodible metallic stent coated with a biodegradable polymer might be able to combine the benefits of both metallic and polymeric biodegradable stents. Finite element modelling can play an important role in the study of nevel stent designs. To correctly simulate the behaviour of degradable stents a material model must be developed that incorporates the effect of degradation on all material characteristics. In case of a coated biocorrodible magnesium stent this includes corrosion modelling, the effect of the coating and the influence of mechanical loading on the corrosion rate.
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Halwani, Dina O., Peter G. Anderson, Brigitta C. Brott, Andreas S. Anayiotos, and Jack E. Lemons. "Local Release of Metallic Ions From Stents Into Vascular Tissue and Associated Alterations of Stent Surfaces." In ASME 2008 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2008. http://dx.doi.org/10.1115/sbc2008-193198.
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In-vivo corrosion of endovascular stents presents two main risks; release of metallic debris and deterioration of the mechanical properties of the stents which may lead to fracture. Retrieval analysis of explanted nickel-titanium (NiTi) aortic stent grafts showed pitting corrosion and fracture of the NiTi wire component [1, 2].
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Kapnisis, Konstantinos, Dina Halwani, Brigitta Brott, Jack Lemons, Peter Anderson, and Andreas Anayiotos. "Biocorrosion and Biomechanical Analysis of Vascular Stents." In ASME 2011 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2011. http://dx.doi.org/10.1115/sbc2011-53378.
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Despite advances in endovascular stent design, stent structural integrity and in-stent restenosis remains a significant clinical problem worldwide. The role of stent corrosion and metallic ion release has not been thoroughly studied and little attention has been given to the interaction of stent materials with the surrounding vessel wall and the mechanical forces involved after implantation. Our recent studies on Stainless Steel (SS), Cobalt-Chromium (CoCr) and Nickel-Titanium (NiTi) stents obtained from a tissue retrieval resource from cadavers with accompanying clinical histories, have revealed that these stents undergo corrosion in vivo, with significant release of metallic ions into surrounding tissues [1]. It is believed that high concentrations of metal ions from stents are toxic to vascular smooth muscle cells [2] and stimulate both inflammatory and fibrotic reactions leading to neointimal formation and a predisposition to device failure [3]. When this is combined with altered biomechanics of flow and motion, it creates a favourable environment for the development of restenosis. To separate the mechanical effects from the local environmental effects on the stent surface, we performed in-vitro mechanical studies on various combinations of stents under low and high curvature and in overlapping positions to compare the results of fretting, pitting and gouging with the explanted stents.
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Shaller, B. D., L. Rathunde, A. S. Conjeevaram, C. Aravena, J. C. Cicenia, T. R. Gildea, M. S. Machuzak, S. Sethi, and F. A. Almeida. "Safety of Fully Covered Metallic Stents for Benign Airways Disease." In American Thoracic Society 2020 International Conference, May 15-20, 2020 - Philadelphia, PA. American Thoracic Society, 2020. http://dx.doi.org/10.1164/ajrccm-conference.2020.201.1_meetingabstracts.a1117.
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Ospina-Delgado, D., J. P. Uribe, K. E. Swenson, M. S. Parikh, J. L. Wilson, S. P. Gangadharan, F. Kheir, C. Zhang, and A. Majid. "Uncovered Self-Expandable Metallic Stents for Expiratory Central Airway Collapse." In American Thoracic Society 2022 International Conference, May 13-18, 2022 - San Francisco, CA. American Thoracic Society, 2022. http://dx.doi.org/10.1164/ajrccm-conference.2022.205.1_meetingabstracts.a4104.
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Karri, Satyaprakash, Stephen Peter, and Pavlos P. Vlachos. "Effect of Stent Design Parameters on Coronary Artery Flow." In ASME 2009 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2009. http://dx.doi.org/10.1115/sbc2009-206569.
Full textAbstract:
The most widely accepted modality for treating diseased arteries is the implantation of endovascular stents. Stents are metallic wireframe devices used to reopen clogged arteries. Despite their widespread use, problems persist post-implantation of these devices beginning with sub-acute thrombus formation followed by inflammation, proliferation and remodeling [1]. The specific stent design and its design parameters profoundly impact the hemodynamic environment of the stent [2], in turn affecting thrombus accumulation between struts and thus restenosis [3]. Prior research examining the hemodynamic effects of stents has been performed in simplified geometries [4] however the effects of stent design parameters such as strut thickness and crown radius of curvature or analysis in realistic geometries is generally lacking. A more thorough understanding of the effect of a stent’s geometric parameters on the arterial flow will provide insight into their long-term performance and will lead to better design.
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Ponkala, Joonas, Mohsin Rizwan, and Panos S. Shiakolas. "On the Design of a Biodegradable POC-HA Polymeric Cardiovascular Stent." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-88703.
Full textAbstract:
The current state of the art in coronary stent technology, tubular structures used to keep the lumen open, is mainly populated by metallic stents coated with certain drugs to increase biocompatibility, even though experimental biodegradable stents have appeared in the horizon. Biodegradable polymeric stent design necessitates accurate characterization of time dependent polymer material properties and mechanical behavior for analysis and optimization. This manuscript presents the process for evaluating material properties for biodegradable biocompatible polymeric composite poly(diol citrate) hydroxyapatite (POC-HA), approaches for identifying material models and three dimensional solid models for finite element analysis and fabrication of a stent. The developed material models were utilized in a nonlinear finite element analysis to evaluate the suitability of the POC-HA material for coronary stent application. In addition, the advantages of using femtosecond laser machining to fabricate the POC-HA stent are discussed showing a machined stent. The methodology presented with additional steps can be applied in the development of a biocompatible and biodegradable polymeric stents.
Reports on the topic "Metallic stents"
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Zhang, Jianhao, Wenming Yang, and Xueting Liu. Comparison of self-expandable metallic stent (SEMS) and preventative stoma (PS) as a bridge to surgery (BTS) for obstructive colorectal cancer. A protocol for systematic review and meta-analysis. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, October 2020. http://dx.doi.org/10.37766/inplasy2020.10.0079.
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