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Zhao G, Liu Q, Tian Y, Liu J, Cheng J, Ni Z. Evaluation of mechanical properties of poly(
L
‐lactic acid) braided stents with axial stiffeners. J Appl Polym Sci 2022. [DOI: 10.1002/app.52242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Gutian Zhao
- School of Mechanical Engineering, Jiangsu Key Laboratory for Design and Manufacture of Micro‐Nano Biomedical Instruments Southeast University Nanjing China
| | - Qingwei Liu
- School of Mechanical Engineering, Jiangsu Key Laboratory for Design and Manufacture of Micro‐Nano Biomedical Instruments Southeast University Nanjing China
| | - Yuan Tian
- School of Mechanical Engineering, Jiangsu Key Laboratory for Design and Manufacture of Micro‐Nano Biomedical Instruments Southeast University Nanjing China
| | - Jinbo Liu
- School of Mechanical Engineering, Jiangsu Key Laboratory for Design and Manufacture of Micro‐Nano Biomedical Instruments Southeast University Nanjing China
| | - Jie Cheng
- School of Mechanical Engineering, Jiangsu Key Laboratory for Design and Manufacture of Micro‐Nano Biomedical Instruments Southeast University Nanjing China
| | - Zhonghua Ni
- School of Mechanical Engineering, Jiangsu Key Laboratory for Design and Manufacture of Micro‐Nano Biomedical Instruments Southeast University Nanjing China
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2
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Micro-endoscopy for Live Small Animal Fluorescent Imaging. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1310:153-186. [PMID: 33834437 DOI: 10.1007/978-981-33-6064-8_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Intravital microscopy has emerged as a powerful technique for the fluorescent visualization of cellular- and subcellular-level biological processes in vivo. However, the size of objective lenses used in standard microscopes currently makes it difficult to access internal organs with minimal invasiveness in small animal models, such as mice. Here we describe front- and side-view designs for small-diameter endoscopes based on gradient-index lenses, their construction, their integration into laser scanning confocal microscopy platforms, and their applications for in vivo imaging of fluorescent cells and microvasculature in various organs, including the kidney, bladder, heart, brain, and gastrointestinal tracts, with a focus on the new techniques developed for each imaging application. The combination of novel fluorescence techniques with these powerful imaging methods promises to continue providing novel insights into a variety of diseases.
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Ramachandra M, Mosayyebi A, Carugo D, Somani BK. Strategies to Improve Patient Outcomes and QOL: Current Complications of the Design and Placements of Ureteric Stents. Res Rep Urol 2020; 12:303-314. [PMID: 32802807 PMCID: PMC7403435 DOI: 10.2147/rru.s233981] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 07/19/2020] [Indexed: 12/13/2022] Open
Abstract
Ureteric stents have played a vital role in relieving urinary obstruction in many urological conditions. Although they are extremely successful, stents have been associated with complications and reduced patients' health-related quality of life (HRQoL). There are many factors that may affect the quality and longevity of stents. In this review, we have highlighted the journey and innovation of ureteric stents through the modern day. A literature review was conducted to identify relevant articles over the last 20 years. There is a plethora of evidence with various indications for the use of ureteral stents and how they affect QoL. There is still ongoing research to develop the ideal stent with reduced encrustation, one that resists infection and is also comfortable for the patients. Stents made from metal alloys, polymers and biodegradable materials have unique properties in their own right but also have certain deficiencies. These have been discussed along with an overview of newly developed stents. Certain pharmacological adjuncts have also been highlighted that may be useful to improve patient's tolerance to stents. In summary, this paper describes the features of the different types of stents and the problems that are frequently encountered, including effect on patients' HRQoL and financial burden to healthcare providers.
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Affiliation(s)
- Meghana Ramachandra
- Department of Urology, University Hospital Southampton NHS Trust, Southampton, UK
| | - Ali Mosayyebi
- Mechanical Engineering Department, Faculty of Engineering and the Environment, University of Southampton, Southampton, UK
- Institute for Life Sciences (IfLS), University of Southampton, UK
| | - Dario Carugo
- Mechanical Engineering Department, Faculty of Engineering and the Environment, University of Southampton, Southampton, UK
- Institute for Life Sciences (IfLS), University of Southampton, UK
| | - Bhaskar K Somani
- Department of Urology, University Hospital Southampton NHS Trust, Southampton, UK
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Balloon-Expandable Biodegradable Stents Versus Self-Expandable Metallic Stents: A Comparison Study of Stent-Induced Tissue Hyperplasia in the Rat Urethra. Cardiovasc Intervent Radiol 2019; 42:1343-1351. [DOI: 10.1007/s00270-019-02239-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 05/02/2019] [Indexed: 01/26/2023]
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Jun EJ, Song HY, Park JH, Bae YS, Paulson B, Lee S, Cho YC, Tsauo J, Kim MT, Kim KY, Yang SG, Kim JK. In Vivo Fluorescence Microendoscopic Monitoring of Stent-Induced Fibroblast Cell Proliferation in an Esophageal Mouse Model. J Vasc Interv Radiol 2018; 29:1756-1763. [PMID: 30266211 DOI: 10.1016/j.jvir.2018.06.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 06/25/2018] [Accepted: 06/29/2018] [Indexed: 11/16/2022] Open
Abstract
PURPOSE To evaluate the feasibility of self-expanding metal stent (SEMS) placement and fluorescence microendoscopic monitoring for determination of fibroblast cell proliferation after stent placement in an esophageal mouse model. MATERIALS AND METHODS Twenty fibroblast-specific protein (FSP)-1 green fluorescent protein (GFP) transgenic mice were analyzed. Ten mice (Group A) underwent SEMS placement, and fluoroscopic and fluorescence microendoscopic images were obtained biweekly until 8 weeks thereafter. Ten healthy mice (Group B) were used for control esophageal values. RESULTS SEMS placement was technically successful in all mice. The relative average number of fibroblast GFP cells and the intensities of GFP signals in Group A were significantly higher than in Group B after stent placement. The proliferative cellular response, including granulation tissue, epithelial layer, submucosal fibrosis, and connective tissue, was increased in Group A. FSP-1-positive cells were more prominent in Group A than in Group B. CONCLUSIONS SEMS placement was feasible and safe in an esophageal mouse model, and proliferative cellular response caused by fibroblast cell proliferation after stent placement was longitudinally monitored using a noninvasive fluorescence microendoscopic technique. The results have implications for the understanding of proliferative cellular response after stent placement in real-life patients and provide initial insights into new clinical therapeutic strategies for restenosis.
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Affiliation(s)
- Eun Jung Jun
- Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88, Olymic-ro 43-gil, Songpa-gu, Seoul, Republic of Korea
| | - Ho-Young Song
- Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88, Olymic-ro 43-gil, Songpa-gu, Seoul, Republic of Korea
| | - Jung-Hoon Park
- Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88, Olymic-ro 43-gil, Songpa-gu, Seoul, Republic of Korea; Department of Biomedical Engineering Research Center, and Convergence Medicine, Asan Medical Center, University of Ulsan College of Medicine, 88, Olymic-ro 43-gil, Songpa-gu, Seoul, Republic of Korea
| | - Yoon Sung Bae
- Department of Biomedical Engineering Research Center, and Convergence Medicine, Asan Medical Center, University of Ulsan College of Medicine, 88, Olymic-ro 43-gil, Songpa-gu, Seoul, Republic of Korea
| | - Bjorn Paulson
- Department of Biomedical Engineering Research Center, and Convergence Medicine, Asan Medical Center, University of Ulsan College of Medicine, 88, Olymic-ro 43-gil, Songpa-gu, Seoul, Republic of Korea; Department of Physics, College of Science, Yonsei University, Seoul, Republic of Korea
| | - Sanghwa Lee
- Department of Biomedical Engineering Research Center, and Convergence Medicine, Asan Medical Center, University of Ulsan College of Medicine, 88, Olymic-ro 43-gil, Songpa-gu, Seoul, Republic of Korea
| | - Young Chul Cho
- Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88, Olymic-ro 43-gil, Songpa-gu, Seoul, Republic of Korea
| | - Jiaywei Tsauo
- Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88, Olymic-ro 43-gil, Songpa-gu, Seoul, Republic of Korea
| | - Min Tae Kim
- Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88, Olymic-ro 43-gil, Songpa-gu, Seoul, Republic of Korea
| | - Kun Yung Kim
- Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88, Olymic-ro 43-gil, Songpa-gu, Seoul, Republic of Korea
| | - Su-Geun Yang
- Department of New Drug Development and NCEED, School of Medicine, Inha University, Incheon, Republic of Korea
| | - Jun Ki Kim
- Department of Biomedical Engineering Research Center, and Convergence Medicine, Asan Medical Center, University of Ulsan College of Medicine, 88, Olymic-ro 43-gil, Songpa-gu, Seoul, Republic of Korea.
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Ni XY, Zhang YH, Zhao HX, Pan CW. Numerical research on the biomechanical behaviour of braided stents with different end shapes and stent-oesophagus interaction. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:e2971. [PMID: 29461690 DOI: 10.1002/cnm.2971] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 12/20/2017] [Accepted: 02/12/2018] [Indexed: 06/08/2023]
Abstract
Quasi-static and dynamic numerical analyses are carried out by referring to computational models of commercial self-expandable braided stents with 3 commonly used end shapes, to evaluate the influence of different end shapes of stent on the biomechanical interaction between stent and oesophagus. The end shape has no influence on the equivalent stress, but has a great influence on the contact stress in the narrowest zone of the oesophagus-neoplasm system. However, the end shapes have significant effect on the equivalent stress and the contact stress in the healthy area of the oesophagus in contact with the stent ends. The results show that the maximum equivalent stress of the oesophagus occurs in the zone contact with the cup-shaped end and the maximum contact stress occurs in the zone contact with the edge of the trumpet-shaped stent end. Moreover, the stent apposition is almost not affected by the end shapes. Although small zones with an incomplete stent apposition appear in the transition zones of spherical-cup-shaped stent, such occurrence might not contribute to stent malapposition or stent migration. Therefore, these stents with 3 types of end shapes all have good stent apposition. Finally, the numerical simulation results can be used to assess the mechanical performance of stents with different end shapes, the effectiveness of stent expansion therapy, and the possibility of complications after stent implantation.
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Affiliation(s)
- Xiao-Yu Ni
- School of Mechanical and Electronic Engineering, Nanjing Forestry University, Nanjing, Jiangsu Province, 210037, China
| | - Yan-Hong Zhang
- School of Mechanical and Electronic Engineering, Nanjing Forestry University, Nanjing, Jiangsu Province, 210037, China
| | - Hai-Xia Zhao
- School of Mechanical and Electronic Engineering, Nanjing Forestry University, Nanjing, Jiangsu Province, 210037, China
| | - Chang-Wang Pan
- Jiangsu Key Laboratory for Design and Manufacture of Micro/Nano Biomedical Instruments Micro-Tech (Nanjing) Co., Ltd., Nanjing, Jiangsu Province, 210037, China
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Abstract
Purpose of Review There are three technological parameters that play a key role on the performance of an ideal stent. These are its material, design and surface coating. This article highlights some fundamental developments that took place in these three areas of stent’s technology, in order to contribute to the identification of an ideal stent. Recent Findings In addition to technological developments concerning stent’s material, design and surface coating, the flow dynamic performance of stents has recently attracted increasing attention. Notably, it has been postulated that the local flow field in a stent is correlated with the deposition of crystals and microorganisms. These findings could potentially revolutionise future stent’s designs, and complement developments made on materials and coatings. Summary The most relevant changes in materials, designs and surface coatings of ureteric stents are reviewed in this article. These are described in the context of a specific cause of stent’s failure they aim to address, with a particular focus on encrustation and biofilm formation.
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Affiliation(s)
- Ali Mosayyebi
- Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, UK. .,Institute for Life Sciences (IfLS), University of Southampton, Southampton, UK.
| | - Costantino Manes
- Department of Environment, Land and Infrastructure Engineering, Politecnico di Torino, Turin, Italy
| | - Dario Carugo
- Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, UK.,Institute for Life Sciences (IfLS), University of Southampton, Southampton, UK
| | - Bhaskar K Somani
- Department of Urology, University Hospital Southampton NHS Trust, Southampton, UK
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Han K, Park JH, Yang SG, Lee DH, Tsauo J, Kim KY, Kim MT, Gang SG, Kim DK, Kim DH, Song HY. EW-7197 eluting nano-fiber covered self-expandable metallic stent to prevent granulation tissue formation in a canine urethral model. PLoS One 2018; 13:e0192430. [PMID: 29447198 PMCID: PMC5813937 DOI: 10.1371/journal.pone.0192430] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 01/11/2018] [Indexed: 01/18/2023] Open
Abstract
PURPOSE To evaluate an EW-7197-eluting nanofiber-covered stent (NFCS) for suppressing granulation tissue formation after stent placement in a canine urethral model. MATERIALS AND METHODS All experiments were approved by the committee of animal research. A total of 12 NFCSs were placed in the proximal and distal urethras of six dogs. Dogs were divided into two groups with 3 dogs each. The control stent (CS) group received NFCSs and the drug stent (DS) group received EW-7197 (1000 μg)-eluting NFCSs. All dogs were sacrificed 8 weeks after stent placement Histologic findings of the stented urethra were compared using the Mann-Whitney U test. RESULTS Stent placement was technically successful in all dogs without procedure-related complications. On urethrographic analysis, the mean luminal diameter was significantly larger in the DS group than in the CS group at 4 and 8 weeks after stent placement (all p < 0.001). On histological examination, mean thicknesses of the papillary projection, thickness of submucosal fibrosis, number of epithelial layers, and degree of collagen deposition were significantly lower in the DS group than in the CS group (all p < 0.001), whereas the mean degree of inflammatory cell infiltration was not significantly different (p > 0.05). CONCLUSION The EW-7197-eluting NFCS is effective and safe for suppressing granulation tissue formation after stent placement in a canine urethral model.
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Affiliation(s)
- Kichang Han
- Department of Radiology, Severance Hospital, Research Institute of Radiological Science, Yonsei University, College of Medicine, Seoul, Republic of Korea
| | - Jung-Hoon Park
- Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
- Department of Biomedical Engineering Research Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
- Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States of America
| | - Su-Geun Yang
- Department of New Drug Development and WCSL, Inha University College of Medicine, Incheon, Republic of Korea
- * E-mail: (SGY); (DHL)
| | - Deok Hee Lee
- Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
- * E-mail: (SGY); (DHL)
| | - Jiaywei Tsauo
- Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Kun Yung Kim
- Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Min Tae Kim
- Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Sung Gwon Gang
- Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Dae-Kee Kim
- College of Pharmacy, Ewha Womans University, Seoul, Republic of Korea
| | - Dong-Hyun Kim
- Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States of America
| | - Ho-Young Song
- Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
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Kim MT, Kim KY, Song HY, Park JH, Tsauo J, Wang Z, Kim PH. Recurrent Benign Urethral Strictures Treated with Covered Retrievable Self-Expandable Metallic Stents: Long-Term Outcomes over an 18-Year Period. J Vasc Interv Radiol 2017; 28:1584-1591. [PMID: 28893465 DOI: 10.1016/j.jvir.2017.07.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 07/10/2017] [Accepted: 07/14/2017] [Indexed: 10/18/2022] Open
Abstract
PURPOSE To assess the long-term outcomes of covered retrievable self-expandable metallic stent (REMS) placement for recurrent benign urethral stricture and to compare the outcomes associated with 3 types of covered REMSs. MATERIALS AND METHODS A retrospective study was performed in 54 male patients in whom 114 REMSs were placed between November 1998 and December 2016. These included 26 polyurethane-covered REMSs in 13 patients (group A), 47 internally polytetrafluoroethylene (PTFE)-covered REMSs in 21 patients (group B), and 41 externally PTFE-covered REMSs in 20 patients (group C). The outcomes were analyzed and compared between the groups. RESULTS Overall clinical success was achieved in 14 of the 54 patients (24%) at 5-year follow-up (group A, 12%; group B, 19%; group C, 40%). The overall complication rate was 60.5%, and the complication rate was significantly higher in group B than in groups A or C (group A vs B, P = .018; group B vs C, P = .002). The median stent indwelling time and maintained patency period were 3.1 months and 108 months, respectively. In multivariate analysis, stent indwelling time was the only significant factor associated with maintained patency. CONCLUSIONS The long-term outcome of covered REMSs has not achieved the desired success rate for the standard treatment of recurrent urethral stricture. However, externally PTFE-covered REMSs showed a better long-term outcome than the other studied types.
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Affiliation(s)
- Min Tae Kim
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Republic of Korea
| | - Kun Yung Kim
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Republic of Korea
| | - Ho-Young Song
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Republic of Korea.
| | - Jung-Hoon Park
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Republic of Korea; Department of Biomedical Engineering Research Center, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Republic of Korea
| | - Jiaywei Tsauo
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Republic of Korea
| | - Zhe Wang
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Republic of Korea; Department of Radiology, Tianjin Medical University General Hospital, Tianjin, P.R. China
| | - Pyeong Hwa Kim
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Republic of Korea
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Kim KY, Park JH, Kim DH, Tsauo J, Kim MT, Son WC, Kang SG, Kim DH, Song HY. Sirolimus-eluting Biodegradable Poly-l-Lactic Acid Stent to Suppress Granulation Tissue Formation in the Rat Urethra. Radiology 2017; 286:140-148. [PMID: 28787263 DOI: 10.1148/radiol.2017170414] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Purpose To investigate the use of sirolimus-eluting biodegradable stents (SEBSs) to suppress granulation tissue formation after stent placement in a rat urethral model. Materials and Methods All experiments were approved by the animal research committee. A total of 36 male Sprague-Dawley rats were randomized into three equal groups after biodegradable stent placement. Group A received control biodegradable stents. Groups B and C received stents coated with 90 µg/cm2 and 450 µg/cm2 sirolimus, respectively. Six rats in each group were sacrificed after 4 weeks; the remaining rats were sacrificed after 12 weeks. The therapeutic effectiveness of SEBSs was assessed by comparing the results of retrograde urethrography and histologic examination. Analysis of variance with post hoc comparisons was used to evaluate statistical differences. Results SEBS placement was technically successful in all rats. Urethrographic and histologic examinations revealed significantly less granulation tissue formation at both time points in the rats receiving SEBSs (groups B and C) compared with those that received control stents (group A) (P < .05 for all). There were no significant differences in urethrographic and histologic findings between groups B and C (P > .05 for all). However, the mean number of epithelial layers in group B was higher than that in group C at 4 weeks after stent placement (P < .001). Apoptosis increased in group C compared with groups A and B (P < .05 for all). Conclusion The use of SEBSs suppressed granulation tissue formation secondary to stent placement in a rat urethral model; local therapy with SEBSs may be used to decrease stent-related granulation tissue formation. © RSNA, 2017.
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Affiliation(s)
- Kun Yung Kim
- From the Department of Radiology and Research Institute of Radiology (K.Y.K., J.H.P., J.T., M.T.K., S.G.K., H.Y.S.), Biomedical Engineering Research Center (J.H.P.), Department of Gastroenterology (Do Hoon Kim), and Department of Pathology (W.C.S.), Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Republic of Korea; and Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, Ill (J.H.P., Dong-Hyun Kim)
| | - Jung-Hoon Park
- From the Department of Radiology and Research Institute of Radiology (K.Y.K., J.H.P., J.T., M.T.K., S.G.K., H.Y.S.), Biomedical Engineering Research Center (J.H.P.), Department of Gastroenterology (Do Hoon Kim), and Department of Pathology (W.C.S.), Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Republic of Korea; and Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, Ill (J.H.P., Dong-Hyun Kim)
| | - Do Hoon Kim
- From the Department of Radiology and Research Institute of Radiology (K.Y.K., J.H.P., J.T., M.T.K., S.G.K., H.Y.S.), Biomedical Engineering Research Center (J.H.P.), Department of Gastroenterology (Do Hoon Kim), and Department of Pathology (W.C.S.), Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Republic of Korea; and Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, Ill (J.H.P., Dong-Hyun Kim)
| | - Jiaywei Tsauo
- From the Department of Radiology and Research Institute of Radiology (K.Y.K., J.H.P., J.T., M.T.K., S.G.K., H.Y.S.), Biomedical Engineering Research Center (J.H.P.), Department of Gastroenterology (Do Hoon Kim), and Department of Pathology (W.C.S.), Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Republic of Korea; and Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, Ill (J.H.P., Dong-Hyun Kim)
| | - Min Tae Kim
- From the Department of Radiology and Research Institute of Radiology (K.Y.K., J.H.P., J.T., M.T.K., S.G.K., H.Y.S.), Biomedical Engineering Research Center (J.H.P.), Department of Gastroenterology (Do Hoon Kim), and Department of Pathology (W.C.S.), Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Republic of Korea; and Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, Ill (J.H.P., Dong-Hyun Kim)
| | - Woo-Chan Son
- From the Department of Radiology and Research Institute of Radiology (K.Y.K., J.H.P., J.T., M.T.K., S.G.K., H.Y.S.), Biomedical Engineering Research Center (J.H.P.), Department of Gastroenterology (Do Hoon Kim), and Department of Pathology (W.C.S.), Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Republic of Korea; and Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, Ill (J.H.P., Dong-Hyun Kim)
| | - Sung-Gwon Kang
- From the Department of Radiology and Research Institute of Radiology (K.Y.K., J.H.P., J.T., M.T.K., S.G.K., H.Y.S.), Biomedical Engineering Research Center (J.H.P.), Department of Gastroenterology (Do Hoon Kim), and Department of Pathology (W.C.S.), Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Republic of Korea; and Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, Ill (J.H.P., Dong-Hyun Kim)
| | - Dong-Hyun Kim
- From the Department of Radiology and Research Institute of Radiology (K.Y.K., J.H.P., J.T., M.T.K., S.G.K., H.Y.S.), Biomedical Engineering Research Center (J.H.P.), Department of Gastroenterology (Do Hoon Kim), and Department of Pathology (W.C.S.), Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Republic of Korea; and Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, Ill (J.H.P., Dong-Hyun Kim)
| | - Ho-Young Song
- From the Department of Radiology and Research Institute of Radiology (K.Y.K., J.H.P., J.T., M.T.K., S.G.K., H.Y.S.), Biomedical Engineering Research Center (J.H.P.), Department of Gastroenterology (Do Hoon Kim), and Department of Pathology (W.C.S.), Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Republic of Korea; and Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, Ill (J.H.P., Dong-Hyun Kim)
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Trela JM, Dechant JE, Culp WT, Whitcomb MB, Palm CA, Nieto JE. Use of an Absorbable Urethral Stent for the Management of a Urethral Stricture in a Stallion. Vet Surg 2016; 45:O41-O48. [DOI: 10.1111/vsu.12530] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 05/26/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Jan M. Trela
- School of Veterinary Medicine; University of California-Davis; Davis California
| | - Julie E. Dechant
- School of Veterinary Medicine; University of California-Davis; Davis California
| | - William T. Culp
- School of Veterinary Medicine; University of California-Davis; Davis California
| | - Mary B. Whitcomb
- School of Veterinary Medicine; University of California-Davis; Davis California
| | - Carrie A. Palm
- School of Veterinary Medicine; University of California-Davis; Davis California
| | - Jorge E. Nieto
- School of Veterinary Medicine; University of California-Davis; Davis California
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Park JH, Song HY, Shin JH, Kim JH, Jun EJ, Cho YC, Kim SH, Park J. Polydioxanone biodegradable stent placement in a canine urethral model: analysis of inflammatory reaction and biodegradation. J Vasc Interv Radiol 2014; 25:1257-1264.e1. [PMID: 24912878 DOI: 10.1016/j.jvir.2014.03.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 03/20/2014] [Accepted: 03/21/2014] [Indexed: 11/17/2022] Open
Abstract
PURPOSE To investigate the inflammatory reaction and perform quantitative analysis of biodegradation after placement of a polydioxanone (PDO) biodegradable stent in a canine urethral model. MATERIALS AND METHODS PDO biodegradable stents were placed in the proximal and distal urethra of nine male mongrel dogs. The dogs were euthanized 4 weeks (group A; n = 3), 8 weeks (group B; n = 3), or 12 weeks (group C; n = 3) after stent placement. The luminal diameter of the stent-implanted urethra was assessed by follow-up retrograde urethrography, and histologic findings were obtained after the dogs were killed. Stents were removed after euthanasia, and their surface morphology and molecular weight were evaluated. Hematologic examination was performed to evaluate inflammatory reaction. RESULTS Stent placement was technically successful in all dogs. The average luminal diameter gradually decreased. The average number of epithelial layers (2.93 vs 4.42; P < .001), the average thickness of papillary projection (0.80 mm vs 1.28 mm; P < .001), and the average thickness of submucosal fibrosis (0.34 mm vs 0.49 mm ; P < .001) were significantly increased in group B versus group A. There were no significant differences between group B and group C. The average inflammatory cell infiltration did not differ significantly in the three groups. Molecular weight losses were 54% in group A and 84% in group B. In group C, PDO stents were completely decomposed. CONCLUSIONS An experimental study in a canine urethral model has demonstrated acceptable inflammatory reaction with gradually increasing granulation tissue but no luminal obstruction within 12 weeks.
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Affiliation(s)
- Jung-Hoon Park
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap 2-dong, Songpa-gu, Seoul 138-736, Republic of Korea
| | - Ho-Young Song
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap 2-dong, Songpa-gu, Seoul 138-736, Republic of Korea.
| | - Ji Hoon Shin
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap 2-dong, Songpa-gu, Seoul 138-736, Republic of Korea
| | - Jin Hyoung Kim
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap 2-dong, Songpa-gu, Seoul 138-736, Republic of Korea
| | - Eun Jung Jun
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap 2-dong, Songpa-gu, Seoul 138-736, Republic of Korea
| | - Young Chul Cho
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap 2-dong, Songpa-gu, Seoul 138-736, Republic of Korea
| | - Soo Hwan Kim
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap 2-dong, Songpa-gu, Seoul 138-736, Republic of Korea
| | - Jihong Park
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap 2-dong, Songpa-gu, Seoul 138-736, Republic of Korea
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Ni XY, Pan CW, Gangadhara Prusty B. Numerical investigations of the mechanical properties of a braided non-vascular stent design using finite element method. Comput Methods Biomech Biomed Engin 2014; 18:1117-1125. [DOI: 10.1080/10255842.2013.873420] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Park JH, Kim JH, Kim EY, Kim J, Song HY, Kim WJ, Lee D, Park J, Kim S. Bioreducible polymer-delivered siRNA targeting MMP-9: suppression of granulation tissue formation after bare metallic stent placement in a rat urethral model. Radiology 2013; 271:87-95. [PMID: 24475825 DOI: 10.1148/radiol.13130980] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To evaluate the effectiveness of small interfering RNA (siRNA) targeting matrix metalloproteinase 9 (MMP-9) in suppressing granulation tissue formation caused by bare metallic stent placement in a rat urethral model. MATERIALS AND METHODS All experiments were approved by the committee of animal research. In 20 Sprague-Dawley male rats (weight range, 300-350 g), a self-expanding metallic bare stent was inserted in the urethra with fluoroscopic guidance. One group of 10 rats (group A) was treated with MMP-9 siRNA/bioreducible branched polyethylenimine-disulfide cross-linked-indocyanine green (bioreducible BPEI-SS-ICG), while the other group of 10 rats (group B) received control siRNA/bioreducible BPEI-SS-ICG treatment. All rats were sacrificed at 4 weeks. The therapeutic effectiveness of the MMP-9 siRNA/bioreducible BPEI-SS-ICG complex was assessed by comparing the two results of retrograde urethrography, histologic examination, and quantification of MMP-9 by using zymography and Western blot analysis between the two groups. The Mann-Whitney U test was used to evaluate differences. RESULTS Stent placement was successful in all rats without a single case of migration at follow-up. Retrograde urethrography performed 4 weeks after stent placement demonstrated significantly larger luminal diameters of the urethra within the stents in group A compared with those in group B (P = .011). Histologic analysis revealed that the mean percentage of granulation tissue area (P < .001), mean number of epithelial layers (P < .001), and mean thickness of submucosal fibrosis (P < .001) were significantly decreased in group A compared with group B. Meanwhile, the mean density of inflammatory cell infiltration did not significantly differ between the two groups (P = .184). Quantitative analysis disclosed MMP-9 levels to be lower in group A relative to group B, indicating positive inhibition of MMP-9 by MMP-9 siRNA/bioreducible BPEI-SS-ICG. CONCLUSION MMP-9 siRNA/bioreducible BPEI-SS-ICG is effective for inhibiting granulation tissue formation after bare metallic stent placement in a rat urethral model.
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Affiliation(s)
- Jung-Hoon Park
- From the Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Asanbyeongwon-gil, 388-1 Pungnap-dong, Songpa-gu, Seoul 138-736, Korea (J.H.P., J.H.K., H.Y.S., J.P., S.K.); Medical Device Development Center, Osong Medical Innovation Foundation, Chungbuk, Korea (E.Y.K.); Department of Radiology, Hanyang University Guri Hospital, Guri, Korea (J.K.); and Center for Self-assembly and Complexity, Institute for Basic Science, and Department of Chemistry, Pohang University of Science and Technology, Pohang, Korea (W.J.K., D.L.)
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Kim EY, Song HY, Kim JH, Fan Y, Park S, Kim DK, Lee EW, Na HK. IN-1233–eluting Covered Metallic Stent to Prevent Hyperplasia: Experimental Study in a Rabbit Esophageal Model. Radiology 2013; 267:396-404. [DOI: 10.1148/radiol.12120361] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Polytetrafluoroethylene-Covered Retrievable Expandable Nitinol Stents for Malignant Esophageal Obstructions: Factors Influencing the Outcome of 270 Patients. AJR Am J Roentgenol 2012; 199:1380-6. [DOI: 10.2214/ajr.10.6306] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Kim EY, Park YS, Shin JH, Cho YJ, Shin DH, Yoon HK, Song HY. The effectiveness of erythromycin in reducing stent-related tissue hyperplasia: an experimental study with a rat esophageal model. Acta Radiol 2012; 53:868-73. [PMID: 22855416 DOI: 10.1258/ar.2012.120351] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND Erythromycin is not only a potent antibiotic; it also has effects of reduction of inflammation and suppression of protein synthesis. PURPOSE To evaluate the impact of erythromycin on tissue hyperplasia after stent placement in a rat esophageal model. MATERIAL AND METHODS A total of 21 rats were included. After placement of self-expanding stents in the mid esophagus, the rats were divided into two experimental groups and one control group. The rats in the experimental groups received daily intraperitoneal injections of erythromycin for 5 weeks; 4 mg/kg (group A, n = 7) and 8 mg/kg (group B, n = 7). Those in the control group (n = 7) received 1 mL of saline intraperitoneally. After sacrifice, histologic analysis was done for thickness of the papillary projection, granulation tissue area, percentage of granulation tissue area, and degree of inflammatory cell infiltration. The statistical significance of differences between groups was assessed by Mann-Whitney U test. RESULTS Tissue hyperplasia as reflected in thickness of papillary projection, granulation tissue area, and percentage of granulation tissue area, was higher in the control group than in the experimental groups, although there was no statistical significance (P = 1.00, 0.332, and 0.263, respectively). However, degree of inflammatory cell infiltration was significantly lower in the experimental groups than the control group (P = 0.025), and the higher dosage of erythromycin reduced inflammatory cell infiltration significantly (P = 0.037). CONCLUSION Intraperitoneal administration of erythromycin is very effective in reducing inflammation after stent placement in a rat esophageal model but has no significant effect on granulation tissue formation.
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Affiliation(s)
- Eun-Young Kim
- Departments of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul
| | - Yang Shin Park
- Departments of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul
- Department of Radiology, Korea University Guro Hospital, Seoul
| | - Ji Hoon Shin
- Departments of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul
| | - Young Jun Cho
- Department of Radiology, Busan Paik Hospital, Inje University College of Medicine, Busan, Korea
| | - Dong-Ho Shin
- Departments of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul
| | - Hyun-Ki Yoon
- Departments of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul
| | - Ho-Young Song
- Departments of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul
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Retrospective comparison of internally and externally covered retrievable stent placement for patients with benign urethral strictures caused by traumatic injury. AJR Am J Roentgenol 2012; 198:W55-61. [PMID: 22194516 DOI: 10.2214/ajr.11.6792] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
OBJECTIVE The purpose of this article is to compare the clinical effectiveness and complications of externally and internally covered stents for the treatment of benign urethral strictures. MATERIALS AND METHODS From July 2002 to June 2010, 59 retrievable self-expandable polytetrafluoroethylene-covered nitinol stents were placed in 33 men with benign urethral strictures. These included 34 internally covered stents placed in 18 patients (group I) and 25 externally covered stents in 15 patients (group E). Stents were routinely removed 4 months after placement from patients who experienced no complications. Complications, duration of stent placement, removal techniques, and maintained patency rates were compared in the two groups. RESULTS Twenty-eight complications (82.4%) occurred in 15 patients in group I, whereas 12 complications (48%) occurred in six patients in group E (p=0.005). Three (16.7%) patients in group I and nine (60%) in group E had their stents electively removed without complications (p=0.010). Stent migration was more frequent in group I (47.1%) than in group E (24.0%). No tissue ingrowth was detected in group E, whereas six cases of tissue ingrowth occurred in group I (p=0.034). The standard technique was used more frequently in group E (70.8%). The median stent indwelling period was significantly shorter in group I than in group E (51.5 vs 114 days; p=0.34). CONCLUSION Despite their relatively high complication rates, externally covered stents are more effective with fewer complications than internally covered stents in the treatment of benign urethral strictures.
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Kim JH, Song HY, Park JH, Yoon HJ, Park HG, Kim DK. IN-1233, an ALK-5 inhibitor: prevention of granulation tissue formation after bare metallic stent placement in a rat urethral model. Radiology 2010; 255:75-82. [PMID: 20308445 DOI: 10.1148/radiol.09090670] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
PURPOSE To evaluate the efficacy of an activin receptor-like kinase-5 inhibitor, IN-1233, for the prevention of tissue hyperplasia after bare stent placement in a rat urethral model. MATERIALS AND METHODS Procedures were performed in accordance with the National Institutes of Health guidelines for humane handling of animals; approval of the committee of animal research was obtained. In 20 Sprague-Dawley male rats (weight range, 300-350 g), a self-expanding metallic bare stent was inserted in the urethra by using fluoroscopic guidance. One group of 10 rats (group A) was treated with IN-1233, the other group of 10 rats (group B) received no treatment. Retrograde urethrography was performed 4 and 8 weeks after stent placement. All rats were sacrificed at 8 weeks for histologic analysis. RESULTS Stent placement was technically successful in all rats. The average stent diameter was significantly larger in group A compared with group B at follow-up retrograde urethrography performed 4 (P = .006) and 8 (P < .001) weeks after stent placement. At histologic analysis, the percentage of granulation tissue area (P < .001), thickness of submucosal fibrosis (P < .001), and number of epithelial layers (P < .001) were significantly decreased in group A compared with group B. Inflammatory cell infiltration (P < .001) was significantly increased in group A compared with group B. CONCLUSION IN-1233 is effective for the prevention of granulation tissue formation after bare metallic stent placement in a rat urethral model.
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Affiliation(s)
- Jin Hyoung Kim
- Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1 Poongnap-2 dong, Songpa-gu, Seoul, Republic of Korea
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Kotsar A, Isotalo T, Uurto I, Mikkonen J, Martikainen P, Talja M, Kellomäki M, Salenius JP, Tammela TL. Urethralin situbiocompatibility of new drug-eluting biodegradable stents: an experimental study in the rabbit. BJU Int 2009; 103:1132-5. [DOI: 10.1111/j.1464-410x.2008.08203.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Chapple CR, Bhargava S. Management of the Failure of a Permanently Implanted Urethral Stent—a Therapeutic Challenge. Eur Urol 2008; 54:665-70. [DOI: 10.1016/j.eururo.2007.11.024] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2007] [Accepted: 11/08/2007] [Indexed: 10/22/2022]
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Kim JH, Song HY, Choi EK, Kim KR, Shin JH, Lim JO. Temporary metallic stent placement in the treatment of refractory benign esophageal strictures: results and factors associated with outcome in 55 patients. Eur Radiol 2008; 19:384-90. [PMID: 18726598 DOI: 10.1007/s00330-008-1151-2] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Revised: 07/11/2008] [Accepted: 07/18/2008] [Indexed: 01/10/2023]
Abstract
The purpose of this study was to evaluate the effectiveness of temporary metallic stenting in 55 patients with treatment-resistant benign esophageal strictures and to identify factors associated with clinical outcomes. Under fluoroscopic guidance, covered retrievable stents were placed in 55 patients with benign esophageal strictures and were removed with retrieval hook 1 week to 6 months after placement. Stent placement was successful in all patients, and the mean dysphagia score was reduced from 2.8 to 1.3 (p<0.001). The most common complications were tissue hyperproliferation (31%), severe pain (24%), and stent migration (25%). During follow-up (mean: 38 months), recurrence of the stricture necessitating balloon dilation was seen in 38 (69%) of 55 patients. Maintained patency rates after temporary stenting at 1, 3, and 6 months and 1, 2, and 4 years were 58%, 43%, 38%, 33%, 26%, and 21%, respectively. In multivariate analysis, length (p=0.003) of the stricture was the only significant factor associated with maintained patency after temporary stenting. In conclusion, temporary metallic stenting for refractory benign esophageal strictures may be effective during the period of stent placement, but is disadvantaged by the high recurrence rates after stent removal, particularly in patients with a long length of stricture (>7 cm).
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Affiliation(s)
- Jin Hyoung Kim
- Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 388-1 Pungnap-2dong, Songpa-gu, Seoul, 138-736, Korea
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Management of recurrent urethral strictures with covered retrievable expandable nitinol stents: long-term results. AJR Am J Roentgenol 2007; 189:1517-22. [PMID: 18029894 DOI: 10.2214/ajr.07.2149] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The purpose of this study was to evaluate the long-term clinical efficacy of temporary placement of covered retrievable stents in the management of recurrent urethral strictures. MATERIALS AND METHODS During the period December 1998-December 2005, 32 men and one adolescent boy (mean age, 48.6 years; range, 16-73 years) with recurrent urethral strictures underwent fluoroscopically guided insertion of a total of 68 stents. Patients without complications underwent elective stent removal 2 or 4 months after stent insertion. Rates of clinical success (long-term clinical and radiographic resolution of urethral strictures) were assessed. The Mann-Whitney U test was used to compare the duration of stent placement in patients with long-term clinical resolution with that in patients with stricture relapse. RESULTS Clinical success was achieved in 18 (55%) of the 33 patients. The mean duration of stent placement in patients with clinical success was significantly different from that in patients who had recurrences (p < 0.0001). Stricture relapse did not occur in only four (20%) of 20 cases of stent placement for 2 months. All 14 stent placements lasting at least 4 months resulted in long-term resolution after a mean follow-up period of 3.6 years. The most common complications necessitating early stent removal were stent migration (33.8% of stents) and tissue hyperplasia (20.6% of stents). CONCLUSION Placement of a covered retrievable stent for a minimum of 4 months is effective in inducing long-term resolution of refractory urethral strictures. Stent migration remains the largest obstacle in achieving adequate duration of stent placement.
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Crisóstomo V, Song HY, Maynar M, Sun F, Soria F, Lima JR, Yoon CJ, Usón-Gargallo J. Evaluation of the Effects of Temporary Covered Nitinol Stent Placement in the Prostatic Urethra: Short-Term Study in the Canine Model. Cardiovasc Intervent Radiol 2007; 30:731-7. [PMID: 17436035 DOI: 10.1007/s00270-007-9006-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE To evaluate the effect of temporary stent placement on the canine prostatic urethra. METHODS Retrievable PTFE-covered nitinol stents were placed in the prostatic urethras of 8 beagle dogs under fluoroscopic guidance. Retrograde urethrography was obtained before and after stenting. Retrograde urethrography and endoscopy were performed 1 and 2 months after deployment. The endoscopic degree of hyperplasia was rated on a scale of 0 to 4 (0 = absence, 4 = occlusion). On day 60, stents were removed and urethrography was performed immediately before euthanasia. Pathologic analysis was performed to determine the degree of glandular atrophy, periurethral fibrosis, and urethral dilation. RESULTS Stent deployment was technically successful in 7 animals, and failed in 1 dog due to a narrow urethral lumen. Complete migration was seen in 2 animals at 1 month, and an additional stent was deployed. On day 30, endoscopy showed slight hyperplasia (grade 1) in 3 animals. On day 60, moderate hyperplasia (grade 2) was evidenced in 4 cases. No impairment of urinary flow was seen during follow-up. Retrieval was technically easy to perform, and was successful in all dogs. The major histologic findings were chronic inflammatory cell infiltrates; prostate glandular atrophy, with a mean value of 1.86 (SD 0.90); periurethral fibrosis, with a mean ratio of 29.37 (SD 10.41); and dilatation of the prostatic urethra, with a mean ratio of 6.75 (SD 3.22). CONCLUSION Temporary prostatic stent placement in dogs is safe and feasible, causing marked enlargement of the prostatic urethral lumen. Retrievable covered stents may therefore be an option for bladder outlet obstruction management in men.
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Affiliation(s)
- Verónica Crisóstomo
- Minimally Invasive Surgery Center, Avda. de la Universidad, s/n Campus Universitario, 10071, Cáceres, Spain.
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Yoon CJ, Song HY, Shin JH, Woo CW, Ro JY, Park HK, Yoon HK. Covered Retrievable Prostatic Urethral Stents: Feasibility Study in a Canine Model. J Vasc Interv Radiol 2006; 17:1813-9. [PMID: 17142712 DOI: 10.1097/01.rvi.0000243613.28211.00] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
PURPOSE To evaluate the feasibility of use of a covered, retrievable prostatic urethral stent and to determine urethrographic and histologic changes in the prostate induced by the stent in a canine model. MATERIALS AND METHODS Polytetrafluoroethylene-covered retrievable nitinol stents were placed in the normal prostatic urethras of 13 dogs. The stents were removed 8 weeks after placement. The dogs were killed immediately after stent removal (group 1, n = 5) or 8 weeks after stent removal (group 2, n = 8). Retrograde urethrograms were obtained every 2 weeks after stent placement and after stent removal in dogs that had not been killed. The histologic changes in the prostate were compared between the two groups. RESULTS Stent placement was technically successful in all dogs. In two dogs, a second stent was placed because of migration of the first stent into the urinary bladder. Stent removal was successful in 12 dogs. One stent was removed in its expanded state. On follow-up urethrograms, dilation of the prostatic urethra persisted until animals were killed (P = .14). The mucosal hyperplasia that occurred after stent placement at both ends of the stent gradually decreased after stent removal (P < .001). Histologic examination revealed prostate glandular atrophy and periurethral fibrosis, which did not differ between the two groups (P = .72 and P = .83, respectively). Papillary hyperplasia of the uroepithelium and submucosal inflammatory cell infiltration was decreased significantly in group 2 compared with group 1 (P = .002, P = .011, respectively). CONCLUSIONS Covered retrievable prostatic urethral stents seem to be feasible for use in the canine prostatic urethra. The stent-induced prostatic urethral dilation and prostate glandular atrophy persist until 8 weeks after stent removal.
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Affiliation(s)
- Chang Jin Yoon
- Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1 Poongnap-2dong, Songpa-gu, Seoul, Republic of Korea
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Shin JH, Song HY, Moon DH, Oh SJ, Kim TH, Lim JO. Rhenium-188 Mercaptoacetyltriglycine–filled Balloon Dilation in the Treatment of Recurrent Urethral Strictures: Initial Experience with Five Patients. J Vasc Interv Radiol 2006; 17:1471-7. [PMID: 16990467 DOI: 10.1097/01.rvi.0000235738.28095.04] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
PURPOSE To evaluate the efficacy of beta-irradiation therapy with use of a rhenium-188 mercaptoacetyltriglycine ((188)Re-MAG(3))-filled balloon for the prevention of restenosis in urethral strictures refractory to repetitive surgical or interventional procedures. MATERIALS AND METHODS Five male patients with traumatic (n = 4) or postoperative anastomotic (n = 1) recurrent urethral strictures were included. One to four sessions of 20-30 Gy beta-irradiation at a 1-mm tissue depth with (188)Re-MAG(3)-filled balloon dilation were undertaken in each patient. RESULTS No procedural complications or toxicities were noted. During the mean follow-up period of 16.2 months, the stricture did not recur in two patients, whereas three patients required additional interventional procedures. In two of these patients, the treatment intervals between the required sessions were significantly prolonged. For the entire group, the mean treatment interval was prolonged from 2.2 months before (188)Re-MAG(3)-filled balloon dilation to 10.7 months after therapy. CONCLUSION (188)Re-MAG(3)-filled balloon dilation shows promise in preventing or delaying stricture recurrence in patients with recurrent urethral strictures.
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Affiliation(s)
- Ji Hoon Shin
- Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 388-1, Pungnap-2dong, Songpa-gu, Seoul 138-736, Korea.
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Kim JH, Shin JH, Song HY, Kang W, Lim JO, Park SH, Ko GY, Yoon HK, Sung KB. Long-term results and factors affecting patency after removal of nasolacrimal stents. J Vasc Interv Radiol 2006; 17:1125-30. [PMID: 16868165 DOI: 10.1097/01.rvi.0000228340.31347.40] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To retrospectively evaluate the long-term patency and prognostic factors affecting patency after removal of nasolacrimal stents. MATERIALS AND METHODS Lacrimal polyurethane stents were removed from 317 lacrimal drainage systems of 275 patients because the stent ceased to function, and immediate and maintained patency were determined with follow-up dacryocystography (DCG) after stent removal. Prognostic factors for patency after stent removal were evaluated by univariate and multivariate analyses for immediate patency and Kaplan-Meier survival analysis and multivariate analysis for maintained patency. RESULTS All stents were successfully removed under fluoroscopic or endoscopic guidance. After stent removal, 243 lacrimal systems (77%) showed immediate patency. The size of the lacrimal sac was the same (65% of cases), widened (2%), or contracted (33%) after stent removal. The shape of the lacrimal sac was normal in 30% and irregular in 70% of cases after stent removal. Seven-day follow-up DCG was obtained in 169 cases, and maintained patency of the lacrimal system was confirmed on 7-day follow-up DCG in 125 cases. Epiphora recurred in 70 cases (56%) during the mean 8-month follow-up period (range, 1-48 months). The mean maintained patency period after stent removal was 15.7 +/- 2.1 months. The maintained patency rates were 41% at 1 year, 31% at 2 years, and 14% at 4 years after stent removal. Multivariate analysis showed that the size of the lacrimal sac (P < .001) was the only factor affecting immediate and maintained patency after stent removal. CONCLUSIONS After stent removal in patients with nasolacrimal stent obstruction, the immediate patency rate was 77%; however, the rate of maintained patency decreased progressively with time. The major factor negatively affecting immediate and maintained patency after stent removal was contraction of the lacrimal sac at the time of stent removal.
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Affiliation(s)
- Jin Hyoung Kim
- Department of Radiology, Armed Forces Byukjae Hospital, Goyang, Korea
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Shin JH, Song HY, Moon DH, Oh SJ, Kim JS, Kim EH, Kim TH, Woo CW, Kim EY, Park SH. Effects of irradiation using a radioisotope-filled balloon on tissue hyperplasia caused by stent placement in a canine urethral model. Acta Radiol 2006; 47:436-43. [PMID: 16739707 DOI: 10.1080/02841850600557125] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
PURPOSE To evaluate 20 Gy and 40 Gy of intraluminal beta-irradiation using a 188Re-7mercaptoacetyltriglycine (MAG3)-filled balloon catheter to reduce tissue hyperplasia caused by covered stent placement for 12 weeks of follow-up in a canine urethral model. MATERIAL AND METHODS Ten dogs underwent 188Re-MAG3-filled balloon dilatation immediately after stent placement; 20 Gy at 1-mm tissue depth in group I (n = 5) and 40 Gy in group II (n = 5), whereas 5 dogs (group III) underwent conventional balloon dilatation only. RESULTS There were no significant differences among the three groups for percentage diameter of stenosis, although this was highest in group III. There was a tendency toward lower mean thickness of the epithelial layer and the papillary projection for out-stent area, and thickness of the papillary projection and degree of inflammatory cells for instent area in groups I and II compared with group III. Thickness of the papillary projection in out-stent area was significantly different among the three groups (P = 0.031). It was significantly less thick in group I than in group III (P < 0.05), whereas group II was not significantly different from group III. CONCLUSION 188Re-MAG3-filled balloon dilatation has the potential to reduce tissue hyperplasia after 12 weeks of follow-up in a canine urethral model. The use of 20 Gy compared to 40 Gy did not show significant differences.
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Affiliation(s)
- Ji Hoon Shin
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
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Shin JH, Song HY, Ko GY, Shim TS, Kim SW, Cho YK, Ko HK, Kim YJ, Yoon HK, Sung KB. Treatment of Tracheobronchial Obstruction with a Polytetrafluoroethylene-covered Retrievable Expandable Nitinol Stent. J Vasc Interv Radiol 2006; 17:657-63. [PMID: 16614149 DOI: 10.1097/01.rvi.0000203803.98007.9f] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
PURPOSE To evaluate the clinical effectiveness of polytetrafluoroethylene (PTFE)-covered retrievable expandable nitinol stents in tracheobronchial strictures. MATERIALS AND METHODS With fluoroscopic guidance, PTFE-covered retrievable expandable nitinol stents were placed in 15 symptomatic patients with benign (n = 6) or malignant (n = 9) tracheobronchial strictures. Complications and improvement in respiratory status were evaluated. Stents were removed electively 6 months after placement in benign strictures or if complications occurred. Membrane degradation or separation from the wire mesh was evaluated in removed stents. RESULTS A total of 17 stents were successfully placed and were well tolerated in all patients. Sputum retention, stent migration, and tissue hyperplasia occurred in 23.5% (n = 4), 17.6% (n = 3), and 17.6% (n = 3) of stents, respectively. A total of 11 stents were successfully removed electively 6 months after placement (n = 4) or when complications occurred (n = 7). All 11 such stents were removed without difficulty with use of standard techniques, antecedent balloon dilation being necessary in two cases as a result of tissue hyperplasia. No removed stent showed signs of membrane degradation, and two removed stents showed signs of membrane separation from the mesh. CONCLUSIONS PTFE-covered retrievable expandable nitinol stents were effective in the treatment of tracheobronchial strictures. Stent removal was easy with use of standard techniques, and no removed stent showed evidence of membrane degradation.
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Affiliation(s)
- Ji Hoon Shin
- Department of Radiology and the Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 388-1, Pungnap-2dong, Songpa-gu, Seoul, 138-736, Korea
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Shin JH, Song HY, Park H, Kim JH, Ko HK, Kim YJ, Woo CW, Kim TH, Ko GY, Yoon HK, Sung KB. Removal of retrievable self-expandable urethral stents: experience in 58 stents. Eur Radiol 2006; 16:2037-43. [PMID: 16528559 DOI: 10.1007/s00330-005-0125-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2005] [Revised: 11/01/2005] [Accepted: 12/12/2005] [Indexed: 10/24/2022]
Abstract
The purpose of this study was to retrospectively evaluate the safety and efficacy of removing retrievable self-expandable urethral stents using a retrieval hook wire. Under fluoroscopic guidance, the removal of 58 polyurethane or PTFE (polytetrafluoroethylene)-covered stents was attempted in 33 patients using a retrieval hook wire. Indications for removal were elective removal (n = 21), stent migration (n = 19), formation of tissue hyperplasia around or inside of the stent (n = 14), stent deformity (n = 3), and severe pain (n = 1). The mean time the stents remained in place was 64.8 +/- 42.9 days (range, 1-177 days). Fifty-six (97%) of the 58 stents were successfully removed using the retrieval hook wire despite the following difficulties; hook wire disconnection (n = 2), untied drawstrings (n = 3), and polyurethane membrane disruption/separation (n = 4). The removal procedure using a retrieval hook wire failed in two stents (3%) which had migrated into the urinary bladder. One of the two stents with migration into the urinary bladder was removed using a snare through the cystostomy route. The overall complication rate was 14% (seven hematuria cases and one urethral tear case), and all were minor and spontaneously resolved without further treatment. In conclusion, removal of retrievable urethral stents using a retrieval hook wire was safe and effective despite some technical difficulties. It is a useful method for allowing temporary stent placement and solving various complications of stent use.
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Affiliation(s)
- Ji Hoon Shin
- Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 388-1, Pungnap-2dong, Songpa-gu, Seoul, 138-736, South Korea
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Shin JH, Song HY, Choi CG, Yuk SH, Kim JS, Kim YM, Yoon CJ, Kim TH, Suh JY, He X. Tissue Hyperplasia: Influence of a Paclitaxel-eluting Covered Stent—Preliminary Study in a Canine Urethral Model. Radiology 2005; 234:438-44. [PMID: 15671001 DOI: 10.1148/radiol.2342040006] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To evaluate a paclitaxel-eluting covered stent in reduction of tissue hyperplasia after stent placement in a canine urethral model. MATERIALS AND METHODS Procedures were performed in accordance with the National Institutes of Health guidelines for humane handling of animals; approval of the committee of animal research was obtained. Twenty paclitaxel-eluting polyurethane-covered stents (drug stents) and 20 polyurethane-covered stents (control stents) were placed alternately between the proximal and distal urethra in 20 male dogs. The dose of paclitaxel was approximately 1800 mug in each drug stent but absent in each control stent. Dogs were sacrificed either 4 (n = 10) or 8 (n = 10) weeks after stent placement. The percentage diameter of stenosis was assessed with follow-up retrograde urethrography and histologic findings obtained after sacrifice and compared between drug stents and control stents and between the proximal and the distal urethra. RESULTS Two drug stents partially migrated during retrograde urethrography immediately after stent placement; they were removed and replaced with a second stent during the same procedure. There was a strong tendency toward a lower percentage diameter of stenosis and numeric mean values of the four histologic findings, which indicates less formation of tissue hyperplasia in the proximal urethra than in the distal urethra. In particular, thickness of the papillary projection denoting the entire thickness of hyperplastic reaction was significantly less in drug stents than in control stents in the proximal urethra in the 8-week group (P = .016, Mann-Whitney U test). CONCLUSION Local delivery of paclitaxel via covered stents has the potential to reduce tissue hyperplasia secondary to stent placement in a canine urethral model. With stent placement, there are distinct differences of tissue hyperplasia between the proximal and distal urethra.
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Affiliation(s)
- Ji Hoon Shin
- Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1 Pungnap-dong, Songpa-gu, Seoul 138-736, Korea
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Kim JH, Shin JH, Shim TS, Hong SJ, Ko GY, Lim JO, Song HY. Results of Temporary Placement of Covered Retrievable Expandable Nitinol Stents for Tuberculous Bronchial Strictures. J Vasc Interv Radiol 2004; 15:1003-8. [PMID: 15361571 DOI: 10.1097/01.rvi.0000133857.09327.1a] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Covered retrievable expandable nitinol stents were successfully placed in nine patients with tuberculous bronchial strictures refractory to balloon dilation. Complications included stent migration (n = 1) and tissue hyperplasia at the proximal portion of the stent (n = 2). During the follow-up period (5-52 months), stricture recurred in three of five patients (60%) after temporary stent placement for 2 months, whereas stricture did not recur in the other four patients after temporary stent placement for 6 months. Temporary placement of covered retrievable stents appears to be an effective method for the treatment of patients with tuberculous bronchial strictures refractory to balloon dilation.
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Affiliation(s)
- Jin Hyoung Kim
- Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Pungnap-dong, Songpa-gu, Seoul 138-736, Korea
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Shin JH, Song HY, Moon DH, Oh SJ, Kim JS, Kim TH, Choi WC, Suh JY, Kang W, Seol HY, Lee JH. Reduction of Tissue Hyperplasia with a Rhenium188 Mercaptoacetyltriglycine-3–filled Balloon: Preliminary Study in a Canine Urethral Model. J Vasc Interv Radiol 2004; 15:737-43. [PMID: 15231888 DOI: 10.1097/01.rvi.0000133523.44219.95] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To evaluate the efficacy of beta-radiation therapy with rhenium-188 mercaptoacetyltriglycine-3 (MAG(3))-filled balloons to reduce tissue hyperplasia secondary to stent placement in 18 canine urethras. MATERIALS AND METHODS Eight dogs were treated with 188-Re MAG(3)-filled balloon dilation immediately after stent placement and were killed 4 weeks later (group I, n = 4) or 8 weeks later (group II, n = 4). Five dogs were treated with 188-Re MAG(3)-filled balloon dilation 2 weeks after stent placement and were killed 4 weeks after stent placement (group III). The remaining five dogs were treated with conventional balloon dilation immediately after stent placement and were killed 4 weeks later; these animals formed the control group (group IV). Retrograde urethrography (RUG) was performed during follow-up and three histologic parameters were investigated: the number of epithelial layers, papillary projection thickness, and degree of submucosal inflammatory cell infiltration. The areas inside and outside the ends of the stents were evaluated in each case after animal sacrifice. After testing statistical significance of data for RUG and histologic findings in the four study groups, the Mann-Whitney U test was used to compare groups I and II to determine delayed effects of irradiation, groups I and III to determine benefits of delayed irradiation, groups I and IV to determine efficacy of immediate irradiation for reducing tissue hyperplasia, and groups III and IV to determine efficacy of delayed irradiation for reducing tissue hyperplasia. RESULTS There were no significant differences in the four study groups on RUG before animal sacrifice. Between groups I and II, group II showed significantly lower mean values in five of six histologic comparisons. Between groups I and III, group III showed significantly lower mean values in only papillary projection thickness inside the stent ends. Between groups I and IV, group I showed significantly lower mean values in all three histologic parameters outside the stent ends. Between groups III and IV, group III showed significantly lower mean values in only two histologic parameters (papillary projection thickness in the in-stent area and inflammatory cell infiltration outside the stent edges). CONCLUSION beta-Irradiation with use of a 188-Re MAG(3)-filled balloon shows the potential to reduce tissue hyperplasia secondary to stent placement in a canine urethral model. Treatment with 188-Re MAG(3)-filled balloons at the time of stent placement shows not only favorable outcomes for reducing tissue hyperplasia but also improved delayed effects until 8 weeks.
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Affiliation(s)
- Ji Hoon Shin
- Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
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Kim JH, Shin JH, Shim TS, Yoon CJ, Lim JO, Ko GY, Yoon HK, Sung KB, Song HY. Efficacy and Safety of a Retrieval Hook for Removal of Retrievable Expandable Tracheobronchial Stents. J Vasc Interv Radiol 2004; 15:697-705. [PMID: 15231883 DOI: 10.1097/01.rvi.0000133506.09685.a3] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
PURPOSE To evaluate the efficacy and safety of use of a retrieval hook for removal of retrievable expandable tracheobronchial stents. MATERIALS AND METHODS With fluoroscopic guidance, a retrieval hook was used to remove 45 retrievable expandable tracheobronchial stents in 31 patients. Indications for stent removal included tissue hyperplasia (n = 16), stent migration (n = 10), stent misplacement (n = 2), tumor overgrowth (n = 2), persistent gastrobronchial fistula (n = 1), and incompletely expanded stent (n = 1). Thirteen stents were electively removed after temporary use. The success rate, causes of failure, and complications related to stent removal with a retrieval hook were analyzed. RESULTS Forty-one of 45 stents (91.1%) were successfully removed with a retrieval hook. The following difficulties were encountered: disruption of the polyurethane membrane (n = 3) and an untied drawstring (n = 1). The removal procedure failed in four cases (8.9%) because of excessive tissue hyperplasia (n = 4) in the proximal portion of the stent. The hook wire fractured in two of the four failed cases. The overall complication rate was 4.4% (minor bleeding, n = 2). CONCLUSION For complications with or temporary use of retrievable expandable tracheobronchial stents, removal with a retrievable hook shows promising initial results.
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Affiliation(s)
- Jin Hyoung Kim
- Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Pungnap-2dong, Songpa-gu, Seoul 138-736, Korea
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