Study of biodegradable and self-expandable PLLA helical biliary stent in vivo and in vitro

Meng, Bo; Wang, Jing; Zhu, Ning; Meng, Qing‐Yuan; Cui, Fuzhai; Xu, Yu

doi:10.1007/s10856-006-9223-9

Cited by 70 publications

(37 citation statements)

References 6 publications

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“…However, the use of covered metal stents needs further evaluation to determine their therapeutic effectiveness. Self-expanding stents made of bioabsorbable material may offer several advantages compared to the plastic and self-expanding metal stents 85,86. Studies in porcine models show that these stents offer improved patency because of their large diameter, lower biofilm accumulation and reduced incidence of bile duct proliferative changes.…”

Section: Future Directionsmentioning

confidence: 99%

Biliary Strictures after Liver Transplantation

Ryu

Lee²

2011

Gut Liver

131

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Biliary strictures are one of the most common complications following liver transplantation, representing an important cause of morbidity and mortality in transplant recipients. The reported incidence of biliary stricture is 5% to 15% following deceased donor liver transplantations and 28% to 32% following living donor liver transplantations. Bile duct strictures following liver transplantation are easily and conveniently classified as anastomotic strictures (AS) or non-anastomotic strictures (NAS). NAS are characterized by a far less favorable response to endoscopic management, higher recurrence rates, graft loss and the need for retransplantation. Current endoscopic strategies to correct biliary strictures following liver transplantation include repeated balloon dilatations and the placement of multiple side-by-side plastic stents. Endoscopic balloon dilatation with stent placement is successful in the majority of AS patients. In patients for whom gaining biliary access is technically difficult, a combined endoscopic and percutaneous/surgical approach proves quite useful. Future directions, including novel endoscopic retrograde cholangiopancreatography techniques, advanced endoscopy, and improved stents could allow for a decreased number of interventions, increased intervals before retreatment, and decreased reliance on percutaneous and surgical modalities. The aim of this review is to detail the present status of endoscopy in the diagnosis, treatment, outcome, and future directions of biliary strictures related to orthotopic liver transplantation from the viewpoint of a clinical gastroenterologists.

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Section: Future Directionsmentioning

confidence: 99%

Biliary Strictures after Liver Transplantation

Ryu

Lee²

2011

Gut Liver

131

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“…These stents are still in the developmental stage and have yet to progress to in vivo studies. It is important to note, that while the focus of this section has been on application of stents in coronary arteries, BSMP stents are also being developed for use in other locations in the body including the urethra, trachea, bile ducts, and intracranial arteries . Application to other areas requires changing the specific stent design, dimensions, and delivery method.…”

Section: Medical Applicationsmentioning

confidence: 99%

Biodegradable Shape Memory Polymers in Medicine

Peterson

Dobrynin

Becker

2017

Adv Healthcare Materials

157

155

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Shape memory materials have emerged as an important class of materials in medicine due to their ability to change shape in response to a specific stimulus, enabling the simplification of medical procedures, use of minimally invasive techniques, and access to new treatment modalities. Shape memory polymers, in particular, are well suited for such applications given their excellent shape memory performance, tunable materials properties, minimal toxicity, and potential for biodegradation and resorption. This review provides an overview of biodegradable shape memory polymers that have been used in medical applications. The majority of biodegradable shape memory polymers are based on thermally responsive polyesters or polymers that contain hydrolyzable ester linkages. These materials have been targeted for use in applications pertaining to embolization, drug delivery, stents, tissue engineering, and wound closure. The development of biodegradable shape memory polymers with unique properties or responsiveness to novel stimuli has the potential to facilitate the optimization and development of new medical applications.

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“…In addition, by comparison with common slotted and wire mesh stents, which have sharp edges, helical stents may reduce potential injury sites upon insertion and subsequently reduce the incidence of restenosis [Bedoya, 2006;Gervaso, 2008]. Beyond some clinical reports [Vaajanen, 2003;Tamura, 1996;Vogt, 2004;Meng, 2006;Venkatraman, 2003], very few studies have been undertaken to evaluate mechanical performance and design of helical stents. It has been found that a typical PLLA-based helical stent has a collapse pressure of 2.5 bar.…”

Section: Helical Stentsmentioning

confidence: 99%

Finite element methods to analyze helical stent expansion

Paryab

Cronin

Lee‐Sullivan

2013

Numer Methods Biomed Eng

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SUMMARYHelical polymeric stents have been proposed as a suitable geometry for biodegradable drug‐eluting polymer‐based stents. However, helical stents often experience nonuniform local expansion (dog boning), which can prohibit full stent expansion using conventional methods. The development of stents and deployment methods is challenging and can be supported by numerical analysis; however, this complex problem is often approached with simplified boundary conditions that may not be appropriate for helical stents. The finite element method (explicit and implicit) was used to investigate three common stent expansion approaches with a focus on helical stent geometry, which differs from traditional wire mesh stent expansion. Although each of the three methods considered provided some insight into the expansion characteristics, common displacement controlled, and uniform expansion methods were not able to demonstrate the characteristic local deformations observed in expansion. A coupled stent‐balloon model, although computationally expensive, was able to demonstrate the expected nonuniform deformation. To address nonuniform expansion, a progressive expansion approach has been investigated and verified numerically. This method may also provide a suitable solution for nonuniform expansion in other stent designs by minimizing loading and potential damage to the artery that can occur during stent deployment. Copyright © 2013 John Wiley & Sons, Ltd.

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Study of biodegradable and self-expandable PLLA helical biliary stent in vivo and in vitro

Cited by 70 publications

References 6 publications

Biliary Strictures after Liver Transplantation

Biliary Strictures after Liver Transplantation

Biodegradable Shape Memory Polymers in Medicine

Finite element methods to analyze helical stent expansion

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