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Wen KC, Li ZA, Liu JH, Zhang C, Zhang F, Li FQ. Recent developments in ureteral stent: Substrate material, coating polymer and technology, therapeutic function. Colloids Surf B Biointerfaces 2024; 238:113916. [PMID: 38636438 DOI: 10.1016/j.colsurfb.2024.113916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 03/21/2024] [Accepted: 04/11/2024] [Indexed: 04/20/2024]
Abstract
The ureteral stent is an effective treatment for clinical ureteral stricture following urological surgery, and the functional coating of the stent could effectively inhibit bacterial colonization and other complications. The present review provides an analysis and description of the materials used in ureteral stents and their coatings. Emphasis is placed on the technological advancements of functional coatings, taking into consideration the characteristics of these materials and the properties of their active substances. Furthermore, recent advances in enhancing the therapeutic efficacy of functional coatings are also reviewed. It is anticipated that this article will serve as a valuable reference providing insights for future research development on new drug-loaded ureteral stents.
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Affiliation(s)
- Kai-Chao Wen
- School of Medicine, Shanghai University, Shanghai 200444, China; Department of Urology/Pharmaceutics, Shanghai Eighth People's Hospital, Shanghai 200235, China
| | - Zheng-An Li
- School of Medicine, Shanghai University, Shanghai 200444, China; Department of Urology/Pharmaceutics, Shanghai Eighth People's Hospital, Shanghai 200235, China
| | - Ji-Heng Liu
- Department of Urology/Pharmaceutics, Shanghai Eighth People's Hospital, Shanghai 200235, China
| | - Chuan Zhang
- School of Medicine, Shanghai University, Shanghai 200444, China.
| | - Feng Zhang
- Department of Urology/Pharmaceutics, Shanghai Eighth People's Hospital, Shanghai 200235, China.
| | - Feng-Qian Li
- School of Medicine, Shanghai University, Shanghai 200444, China; Department of Urology/Pharmaceutics, Shanghai Eighth People's Hospital, Shanghai 200235, China.
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Pagonis K, Peteinaris A, Adamou C, Tatanis V, Vagionis A, Natsos A, Obaidat M, Faitatziadis S, Liatsikos E, Kallidonis P. Minimal invasive treatment of urethral strictures: An experimental study of the effect of paclitaxel coated balloons in the wall of strictured rabbit's urethra. Arch Ital Urol Androl 2024; 96:12248. [PMID: 38389459 DOI: 10.4081/aiua.2024.12248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Accepted: 01/15/2024] [Indexed: 02/24/2024] Open
Abstract
PURPOSE The aim of this study is the evaluation of the distribution of paclitaxel (PTX) released by a coated balloon in the layers of rabbit's urethra. METHODS 18 rabbits were included. A laser device was used for the stricture formation. After two weeks, dilation of the strictured urethra was performed by using Advance 35LP PTA balloons and Advance 18 PTX PTA balloons. The experimental models were divided into 3 groups. The group Α included two rabbits without any intervention except for the stenosis procedure. Group B compromised six rabbits that underwent dilation with Advance 35LP PTA balloons. Group C consisted of 10 rabbits to which dilation with both Advance 35LP PTA balloons and Advance 18 PTX PTA balloons was applied. Histological evaluation and Immunohistochemistry were performed on all specimens. RESULTS Inflammation, fibrosis and ruptures were detected in the specimens of the study. In specimens of Group C the decrease of inflammation and fibrosis rate was greater. Anti-PTX antibody was detected in the epithelium, lamina propria and smooth muscle layer of all specimens of urethras that have been harvested immediately and 1 day after the dilation with Advance 18 PTX PTA balloon and it was not observed in any layer of the urethral wall of the rest of the examined specimens of Group C. CONCLUSIONS PTX's enrichment was detected in the smooth muscle layer of all specimens that have been harvested immediately and 24h after the dilation with Advance 18 PTX PTA balloons. PTX may play an inhibitive role in the recurrence of the stenosis.
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Duan L, Li L, Zhao Z, Wang X, Zheng Z, Li F, Li G. Antistricture Ureteral Stents with a Braided Composite Structure and Surface Modification with Antistenosis Drugs. ACS Biomater Sci Eng 2024; 10:607-619. [PMID: 38047884 DOI: 10.1021/acsbiomaterials.3c00781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
The present work describes the development of a drug-loaded ureteral stent with antistricture function based on a trilayer design in which the middle layer was braided from biodegradable poly(p-dioxanone) (PDO) monofilament. Antistenosis drugs rapamycin and paclitaxel were loaded into a silk fibroin (SF) solution and coated on the inner and outer layers of the braided PDO stent. The cumulative release of rapamycin and paclitaxel was sustained over 30 days, with a total release above 80%. The drug-loaded ureteral stents inhibited the proliferation of fibroblasts and smooth muscle cells in vitro. Subcutaneous implantation in rats showed that the drug-loaded ureteral stents were biocompatible with durable mechanical properties in vivo, revealing the inhibition of an excessive growth of fibroblasts and excessive deposition of collagen fibers. In conclusion, the dual-drug-loaded biodegradable ureteral stents show the possibility for treatment of ureteral strictures and avoid the occurrence of complications such as inflammation and restricture.
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Affiliation(s)
- Lirong Duan
- National Engineering Laboratory for Modern Silk, College of Textile and Clothing Engineering, Soochow University, Suzhou 215123, China
- Jiangsu Advanced Textile Engineering Technology Center, Nantong 226007, China
| | - Lu Li
- National Engineering Laboratory for Modern Silk, College of Textile and Clothing Engineering, Soochow University, Suzhou 215123, China
- Jiangsu Advanced Textile Engineering Technology Center, Nantong 226007, China
| | - Zeyu Zhao
- Department of Applied Physics, The Hong Kong Polytechnic University, 11 Yukchoi Rd., Hung Hom, Kowloon 10087, Hong Kong, P. R. China
| | - Xiaoqin Wang
- National Engineering Laboratory for Modern Silk, College of Textile and Clothing Engineering, Soochow University, Suzhou 215123, China
| | - Zhaozhu Zheng
- National Engineering Laboratory for Modern Silk, College of Textile and Clothing Engineering, Soochow University, Suzhou 215123, China
| | - Feng Li
- Department of Urology, The First Affiliated Hospital of Soochow University, Suzhou 215006, China
| | - Gang Li
- National Engineering Laboratory for Modern Silk, College of Textile and Clothing Engineering, Soochow University, Suzhou 215123, China
- Jiangsu Advanced Textile Engineering Technology Center, Nantong 226007, China
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Graczyk S, Pasławski R, Grzeczka A, Pasławska U, Świeczko-Żurek B, Malisz K, Popat K, Sionkowska A, Golińska P, Rai M. Antimicrobial and Antiproliferative Coatings for Stents in Veterinary Medicine-State of the Art and Perspectives. MATERIALS (BASEL, SWITZERLAND) 2023; 16:6834. [PMID: 37959431 PMCID: PMC10649059 DOI: 10.3390/ma16216834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 10/20/2023] [Accepted: 10/22/2023] [Indexed: 11/15/2023]
Abstract
Microbial colonization in veterinary stents poses a significant and concerning issue in veterinary medicine. Over time, these pathogens, particularly bacteria, can colonize the stent surfaces, leading to various complications. Two weeks following the stent insertion procedure, the colonization becomes observable, with the aggressiveness of bacterial growth directly correlating with the duration of stent placement. Such microbial colonization can result in infections and inflammations, compromising the stent's efficacy and, subsequently, the animal patient's overall well-being. Managing and mitigating the impact of these pathogens on veterinary stents is a crucial challenge that veterinarians and researchers are actively addressing to ensure the successful treatment and recovery of their animal patients. In addition, irritation of the tissue in the form of an inserted stent can lead to overgrowth of granulation tissue, leading to the closure of the stent lumen, as is most often the case in the trachea. Such serious complications after stent placement require improvements in the procedures used to date. In this review, antibacterial or antibiofilm strategies for several stents used in veterinary medicine have been discussed based on the current literature and the perspectives have been drawn. Various coating strategies such as coating with hydrogel, antibiotic, or other antimicrobial agents have been reviewed.
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Affiliation(s)
- Szymon Graczyk
- Institute of Veterinary Medicine, Department of Biological and Veterinary Sciences, Nicolaus Copernicus University, Lwowska 1, 87-100 Torun, Poland; (R.P.); (A.G.); (U.P.)
| | - Robert Pasławski
- Institute of Veterinary Medicine, Department of Biological and Veterinary Sciences, Nicolaus Copernicus University, Lwowska 1, 87-100 Torun, Poland; (R.P.); (A.G.); (U.P.)
| | - Arkadiusz Grzeczka
- Institute of Veterinary Medicine, Department of Biological and Veterinary Sciences, Nicolaus Copernicus University, Lwowska 1, 87-100 Torun, Poland; (R.P.); (A.G.); (U.P.)
| | - Urszula Pasławska
- Institute of Veterinary Medicine, Department of Biological and Veterinary Sciences, Nicolaus Copernicus University, Lwowska 1, 87-100 Torun, Poland; (R.P.); (A.G.); (U.P.)
| | - Beata Świeczko-Żurek
- Department of Biomaterials Technology, Faculty of Mechanical Engineering and Ship Technology, Gdansk University of Technology, Gabriela Narutowicza 11/12, 80-229 Gdansk, Poland; (B.Ś.-Ż.); (K.M.)
| | - Klaudia Malisz
- Department of Biomaterials Technology, Faculty of Mechanical Engineering and Ship Technology, Gdansk University of Technology, Gabriela Narutowicza 11/12, 80-229 Gdansk, Poland; (B.Ś.-Ż.); (K.M.)
| | - Ketul Popat
- Department of Mechanical Engineering, Colorado State University, Fort Collins, CO 80523, USA;
| | - Alina Sionkowska
- Department of Biomaterials and Cosmetic Chemistry, Faculty of Chemistry, Nicolaus Copernicus University in Torun, Gagarina 7, 87-100 Torun, Poland
| | - Patrycja Golińska
- Department of Microbiology, Nicolaus Copernicus University, ul. Lwowska 1, 87-100 Torun, Poland;
| | - Mahendra Rai
- Department of Chemistry, Federal University of Piaui (UFPI), Teresina 64049-550, Brazil;
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Li L, Li F, Zhao Z, Xie R, Xu D, Ding M, Zhang J, Shen D, Fei J. An exploratory research on antitumor effect of drug-eluting slow-releasing electrospinning membranes. Heliyon 2023; 9:e20295. [PMID: 37822614 PMCID: PMC10562749 DOI: 10.1016/j.heliyon.2023.e20295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 09/18/2023] [Accepted: 09/18/2023] [Indexed: 10/13/2023] Open
Abstract
Objective To evaluate the long-term inhibition of malignant biliary tumor growth using paclitaxel (PTX)-covered polycaprolactone (PCL) electrospun membranes. Methods A mixture of PCL, a material used to fabricate polymer stents, and PTX, a widely used chemotherapeutic agent, was synthesized by electrospinning. After preparing the drug-eluting membrane, drug release and fiber degradation were assessed in vitro under different pH conditions. The QBC939 cholangiocarcinoma cell line was cultured to establish a xenograft nude mouse model. Finally, the drug-eluting membrane was implanted into the mouse model, and the relative tumor inhibition rate was evaluated. Results A new PTX-loaded PCL electrospun fiber membrane was developed. The drug release rate was about 20-40% in the 32-day release cycle, and the release quantity was between 20 and 170 mg. As pH decreased, the release rate increased significantly. The degradation rate of the fiber membranes in vitro was approximately 20-48%, and was positively correlated with the drug loading rate. In animal experiments, the growth of tumors in mice was suppressed using drug-eluting membranes. Conclusion The PTX-loaded PCL electrospun fiber membrane enhanced the long-term drug release and exhibited excellent antitumor effects in vivo.
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Affiliation(s)
- Li Li
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Air Force Medical University, Xi'an, Shaanxi Province, China
| | - Feng Li
- Department of Emergency, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Zhifeng Zhao
- Xijing Hospital of Digestive Diseases, Air Force Military Medical University, Xi'an, Shaanxi Province, China
| | - Rongli Xie
- Department of General Surgery, Ruijin Hospital Luwan Branch, Affiliated to Shanghai Jiao Tong University, Shanghai, China
| | - Dan Xu
- Department of General Surgery, Ruijin Hospital, Affiliated to Shanghai Jiao Tong University, Shanghai, China
| | - Min Ding
- Department of General Surgery, Ruijin Hospital, Affiliated to Shanghai Jiao Tong University, Shanghai, China
| | - Jun Zhang
- Department of General Surgery, Ruijin Hospital, Affiliated to Shanghai Jiao Tong University, Shanghai, China
| | - Dongjie Shen
- Department of General Surgery, Ruijin Hospital Luwan Branch, Affiliated to Shanghai Jiao Tong University, Shanghai, China
| | - Jian Fei
- Department of General Surgery, Ruijin Hospital, Affiliated to Shanghai Jiao Tong University, Shanghai, China
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Sirolimus-eluting cobalt-chrome alloy stent suppresses stent-induced tissue hyperplasia in a porcine Eustachian tube model. Sci Rep 2022; 12:3436. [PMID: 35236923 PMCID: PMC8891339 DOI: 10.1038/s41598-022-07471-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 02/11/2022] [Indexed: 11/09/2022] Open
Abstract
Various preclinical studies with developed Eustachian tube (ET) stents are in progress but have not yet been clinically applied. ET stent is limited by stent-induced tissue hyperplasia in preclinical studies. The effectiveness of sirolimus-eluting cobalt–chrome alloy stent (SES) in suppressing stent-induced tissue hyperplasia after stent placement in the porcine ET model was investigated. Six pigs were divided into two groups (i.e., the control and the SES groups) with three pigs for each group. The control group received an uncoated cobalt–chrome alloy stent (n = 6), and the SES group received a sirolimus-eluting cobalt–chrome alloy stent (n = 6). All groups were sacrificed 4 weeks after stent placement. Stent placement was successful in all ETs without procedure-related complications. None of the stents was able to keep its round shape as original, and mucus accumulation was observed inside and around the stent in both groups. On histologic analysis, the tissue hyperplasia area and the thickness of submucosal fibrosis were significantly lower in the SES group than in the control group. SES seems to be effective in suppressing stent-induced tissue hyperplasia in porcine ET. However, further investigation was required to verify the optimal stent materials and antiproliferative drugs.
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Jaworska J, Stojko M, Włodarczyk J, Janeczek H, Godzierz M, Musiał‐Kulik M, Bryniarski P, Kasperczyk J. Docetaxel‐loaded scaffolds manufactured by
3D
printing as model, biodegradable prostatic stents. J Appl Polym Sci 2022. [DOI: 10.1002/app.52283] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Joanna Jaworska
- Centre of Polymer and Carbon Materials, Polish Academy of Sciences Zabrze Poland
| | - Mateusz Stojko
- Centre of Polymer and Carbon Materials, Polish Academy of Sciences Zabrze Poland
- Department of Biopharmacy, Faculty of Pharmaceutical Sciences in Sosnowiec Medical University of Silesia in Katowice Sosnowiec Poland
| | - Jakub Włodarczyk
- Centre of Polymer and Carbon Materials, Polish Academy of Sciences Zabrze Poland
| | - Henryk Janeczek
- Centre of Polymer and Carbon Materials, Polish Academy of Sciences Zabrze Poland
| | - Marcin Godzierz
- Centre of Polymer and Carbon Materials, Polish Academy of Sciences Zabrze Poland
| | - Monika Musiał‐Kulik
- Centre of Polymer and Carbon Materials, Polish Academy of Sciences Zabrze Poland
| | - Piotr Bryniarski
- Department of Urology, Faculty of Medical Sciences in Zabrze Medical University of Silesia in Katowice Zabrze Poland
| | - Janusz Kasperczyk
- Centre of Polymer and Carbon Materials, Polish Academy of Sciences Zabrze Poland
- Department of Biopharmacy, Faculty of Pharmaceutical Sciences in Sosnowiec Medical University of Silesia in Katowice Sosnowiec Poland
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Kallidonis P, Adamou C, Castillo SV, Liourdi D, Liatsikos E, Lange D. Drug-delivering devices in the urinary tract: A systematic review. Arab J Urol 2021; 19:191-204. [PMID: 34104496 PMCID: PMC8158184 DOI: 10.1080/2090598x.2021.1885948] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Objective : To systematically review the use of drug-eluting stents (DES) and drug-coated balloons (DCB) in urology. Materials and Methods The systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. PubMed, Scopus, Web of science and Cochrane Library online databases were searched in February 2019. Experimental and clinical studies, which included the placement of a DES or dilatation with DCB for investigating their potential use in the urinary tract for the management of ureteric or urethral pathologies, were included. The primary endpoint was to evaluate the current use of DES and DCB in urology. Results A total of 29 articles were included in the systematic review. A total of 10 studies tested DES or DCB containing anti-proliferative agents (paclitaxel, zotarolimus, sirolimus, halofugione). Antibiotic agent-containing DES were tested in nine studies (triclosan, quinolones, teicoplanin, nitrofurantoin, silver sulfadiazine). A total of eight studies investigated the release of anti-inflammatory agents by DES (ketorolac, indomethacin, EW-7197). Another group studied heparin-eluting stents. Conclusion Despite the inconclusive outcomes of the three randomised controlled trials, drug-coated/eluting devices constitute a promising field in urology for the prevention of complications associated with conventional stents including pain and encrustation. Pre-clinical in vitro and in vivo studies have shown their ability to mitigate inflammation, inhibit re-stenosis and improve pain as indicated by declined use of anti-inflammatory drugs. Abbreviations: DES: drug-eluting stents; DCB: drug-coated balloons; DCS: drug-coated stents; HF: halofungione; MCP-1: monocyte chemoattractant protein 1; PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses; PTCA: percutaneous transluminal coronary angioplasty; RANTES: regulated on activation, normal T-cell expressed and secreted; RCT: randomised controlled trial; USSQ, Ureteric Stent Symptoms Questionaire.
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Affiliation(s)
- Panagiotis Kallidonis
- Department of Urology, University Hospital of Patras, Patras, Greece.,Endourological Society, Ureteral Stent Research Group
| | | | | | | | | | - Dirk Lange
- Endourological Society, Ureteral Stent Research Group.,Department of Urologic Sciences, University of British Columbia, Vancouver, BC, Canada
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Park JH, Kim MT, Kim KY, Bakheet N, Kim TH, Jeon JY, Park W, Lopera JE, Kim DH, Song HY. Local Heat Treatment for Suppressing Gastroduodenal Stent-Induced Tissue Hyperplasia Using Nanofunctionalized Self-Expandable Metallic Stent in Rat Gastric Outlet Model. ACS Biomater Sci Eng 2020; 6:2450-2458. [PMID: 33455352 DOI: 10.1021/acsbiomaterials.0c00307] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Despite the promising results from the placement of covered or uncovered self-expandable metallic stent (SEMS) as a nonsurgical therapeutic option for the malignant gastric outlet obstruction (GOO), the long patency of the stent is still limited because of stent-induced tissue hyperplasia. Here, a local heat treatment using a nanofunctionalized SEMS is proposed for suppressing stent-induced tissue hyperplasia during GOO treatment. Highly efficient photothermal gold nanoparticle (GNP) transducer-coated SEMSs (GNP-SEMSs) were prepared for local heat treatment in rat gastric outlet. The in vivo heating temperature in rat gastric outlet model was evaluated and compared with in vitro heating temperature. Three groups of our developed 45 rat gastric outlet models were used: group A, noncoated SEMS only; group B, GNP-SEMS plus local heating; and group C, GNP-SEMS only to investigate in vivo efficacy of GNP-SEMS mediated local heating. Ten rats per group were sacrificed for 4 weeks, and five rats per group were sacrificed immediately after local heat treatment. The in vivo heating temperature was found to be 10.8% lower than the in vitro heating temperatures. GNP-SEMSs were successfully placed through a percutaneous approach into the rat gastric outlet (n = 45). The therapeutic effects of GNP-SEMS were assessed by histologic examination including hematoxylin-eosin, Masson trichrome, immunohistochemistry (TUNEL and CD31), and immunofluorescence (Ki67), and the results showed significant prevention of tissue hyperplasia following stent placement without adjacent gastrointestinal tissue damage. GNP-SEMS-mediated local heating could be an alternative therapeutic option for the suppression of tissue hyperplasia following stent placement in benign and malignant GOOs.
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Affiliation(s)
- Jung-Hoon Park
- Departments of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Republic of Korea.,Biomedical Engineering Research Center, Asan Institute for Life Sciences, Asan Medical Center, 88 Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea
| | - Min Tae Kim
- Departments of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Republic of Korea.,Department of Radiologic Technology, Cheju Halla University, 38, Halladaehak-ro, Jeju-si, Jeju-do 63092, Republic of Korea
| | - Kun Yung Kim
- Departments of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Republic of Korea
| | - Nader Bakheet
- Departments of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Republic of Korea
| | - Tae-Hyung Kim
- Department of Radiological Science, Kangwon National University, 346 Hwangjo-gil, Dogye-eup, Samcheok-si, Kangwon-do 25949, Republic of Korea
| | - Jae Yong Jeon
- Rehabilitation, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Republic of Korea
| | - Wooram Park
- Department of Biomedical Chemical Engineering, The Catholic University of Korea, 43 Jibong-ro, Bucheon-si, Gyeonggi 14662, Republic of Korea
| | - Jorge E Lopera
- Department of Radiology, UT Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, Texas 78229, United States
| | - Dong-Hyun Kim
- Department of Radiology, Feinberg School of Medicine, and Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, Illinois 60611, United States
| | - Ho-Young Song
- Departments of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Republic of Korea
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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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Paclitaxel-coated stents to prevent hyperplastic proliferation of ureteral tissue: from in vitro to in vivo. Urolithiasis 2018; 48:47-56. [PMID: 30259058 DOI: 10.1007/s00240-018-1081-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 09/17/2018] [Indexed: 10/28/2022]
Abstract
Ureteric stents have become an indispensable tool in the armamentarium of every urologist. However, they carry their own morbidity resulting mostly from infectious or abacterial fouling and biofilm formation, and/or urothelial hyperplastic reaction. All of these may interact and lead to clinical complications. Many different stent designs and coatings have been proposed. In this study, we focused on the effect of paclitaxel-coated stents on hyperplastic proliferation of ureteral tissue, using as example anastomotic strictures after ureteroureterostomy in a rat model. Human urothelial cells (SV-HUC-1) were used to determine paclitaxel dosages in vitro. Polyurethane stents were coated with a paclitaxel containing biodegradable polymer and studied in a ureteroureterostomy rat model. 48 male 9-week-old Sprague-Dawley rats underwent either sham surgery (n = 16) or ureteroureterostomy with sutured anastomosis, and consecutive stenting with either a paclitaxel-coated or an uncoated stent (16 per group), respectively. The animals received daily intraperitoneal injections of 5-bromo-2-deoxyuridine (20 mg/ml, 100 mg/kg body weight) during the first eight postoperative days, and were sacrificed on day 28. Healing of the ureteral anastomosis and proliferation of urothelial cells was examined histologically and immunohistochemically. In vitro, a concentration of 10 ng/mm2 paclitaxel can be considered as non-toxic, while still exerting an anti-proliferative effect on urothelial cells. Histologically, typical wound healing processes were seen at the site of the ureteral anastomosis in vivo. Proliferation of urothelial cells was significantly lower in animals with paclitaxel-coated stents compared to those with uncoated stents (LI 41.27 vs. 51.58, p < 0.001). Our results indicate that stenting of ureteral anastomoses with paclitaxel-coated stents can reduce hyperplastic proliferation of ureteral tissue. Paclitaxel-coated stents thus might be able to prevent not only scar-induced postoperative stenosis after reconstructive surgery, but also hyperplastic urothelial reaction in non-anastomotic stent patients as part of their inflammatory response to the foreign material.
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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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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 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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Jun EJ, Park JH, Tsauo J, Yang SG, Kim DK, Kim KY, Kim MT, Yoon SH, Lim YJ, Song HY. EW-7197, an activin-like kinase 5 inhibitor, suppresses granulation tissue after stent placement in rat esophagus. Gastrointest Endosc 2017; 86:219-228. [PMID: 28137596 DOI: 10.1016/j.gie.2017.01.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 01/10/2017] [Indexed: 02/08/2023]
Abstract
BACKGROUND AND AIMS Self-expanding metallic stent (SEMS) placement is a well-established method for treating malignant esophageal strictures; however, this procedure has not gained widespread acceptance for treating benign esophageal strictures because of granulation tissue formation. The aim of the present study was to investigate whether EW-7197, a novel per-oral transforming growth factor-β type I receptor kinase inhibitor, suppressed granulation tissue formation after SEMS placement in the rat esophagus. METHODS Sixty rats underwent SEMS placement and were randomly divided into 4 groups. Group A (n = 20) received vehicle-treated control for 4 weeks. Group B (n = 20) received 20 mg/kg/day EW-7197 for 4 weeks. Group C (n = 10) received 20 mg/kg/day EW-7197 for 4 weeks followed by vehicle-treated control for 4 weeks. Group D (n = 10) received 20 mg/kg/day EW-7197 for 8 weeks. RESULTS SEMS placement was technically successful in all rats. Eleven rats, however, were excluded because of stent migration (n = 9) and procedure-related death (n = 2). The luminal diameter in group A was significantly smaller than those in groups B, C, and D (all P < .001). The percentage of granulation tissue area, number of epithelial layers, thickness of submucosal fibrosis, percentage of connective tissue area, and degree of collagen deposition were significantly higher in group A than in groups B, C, and D (all P < .001); however, there were no significant differences among groups B, C, and D. EW-7197 decreased the expression levels of phospho-Smad 3, N-cadherin, fibronectin, α-smooth muscle actin, and transforming growth factor-β1 and increased the expression level of E-cadherin (all P < .01). CONCLUSIONS EW-7197 suppressed granulation tissue formation after SEMS placement in the rat esophagus.
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Affiliation(s)
- Eun Jung Jun
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Jung-Hoon Park
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea; Biomedical Engineering Research Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Jiaywei Tsauo
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Su-Geun Yang
- Department of New Drug Development and NCEED, School of Medicine, Inha University, Incheon, Republic of Korea
| | - Dae-Kee Kim
- Graduate School of Pharmaceutical Sciences, College of Pharmacy, Ewha Women's University, Seoul, Republic of Korea
| | - Kun Yung Kim
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Min Tae Kim
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Sung-Hwan Yoon
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Young Je Lim
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Ho-Young Song
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
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Abstract
Urethral stricture/stenosis is a narrowing of the urethral lumen. These conditions greatly impact the health and quality of life of patients. Management of urethral strictures/stenosis is complex and requires careful evaluation. The treatment options for urethral stricture vary in their success rates. Urethral dilation and internal urethrotomy are the most commonly performed procedures but carry the lowest chance for long-term success (0–9%). Urethroplasty has a much higher chance of success (85–90%) and is considered the gold-standard treatment. The most common urethroplasty techniques are excision and primary anastomosis and graft onlay urethroplasty. Anastomotic urethroplasty and graft urethroplasty have similar long-term success rates, although long-term data have yet to confirm equal efficacy. Anastomotic urethroplasty may have higher rates of sexual dysfunction. Posterior urethral stenosis is typically caused by previous urologic surgery. It is treated endoscopically with radial incisions. The use of mitomycin C may decrease recurrence. An exciting area of research is tissue engineering and scar modulation to augment stricture treatment. These include the use of acellular matrices or tissue-engineered buccal mucosa to produce grafting material for urethroplasty. Other experimental strategies aim to prevent scar formation altogether.
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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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Yang L, Whiteside S, Cadieux PA, Denstedt JD. Ureteral stent technology: Drug-eluting stents and stent coatings. Asian J Urol 2015; 2:194-201. [PMID: 29264145 PMCID: PMC5730737 DOI: 10.1016/j.ajur.2015.08.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Accepted: 08/24/2015] [Indexed: 02/05/2023] Open
Abstract
Ureteral stents are commonly used following urological procedures to maintain ureteral patency. However, alongside the benefits of the device, indwelling stents frequently cause significant patient discomfort (pain, urgency, frequency) and can become encrusted and infected. The importance of these sequelae is that they are not only bothersome to the patient but can lead to significant morbidity, urinary retention, ureteral damage, recurrent infections, pyelonephritis and sepsis. When these problems occur, stent removal or replacement alongside antibiotic, analgesic and/or other symptom-modifying therapies are essential to successfully treat the patient. In an attempt to prevent such morbidity, numerous approaches have been investigated over the past several decades to modify the stent itself, thereby affecting changes locally within the urinary tract without significant systemic therapy. These strategies include changes to device design, polymeric composition, drug-elution and surface coatings. Of these, drug-elution and surface coatings are the most studied and display the most promise for advancing ureteral stent use and efficacy. This article reviews these two strategies in detail to determine their clinical potential and guide future research in the area.
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Affiliation(s)
- Luo Yang
- Department of Surgery, Division of Urology, No.4 West China Hospital, Sichuan University, Chengdu, Sichuan, China.,Department of Urology of West China Hospital of Sichuan University, Chengdu, Sichuan, China.,Department of Surgery, Division of Urology, Western University, London, Ontario, Canada
| | - Samantha Whiteside
- Department of Microbiology and Immunology, Western University, London, Ontario, Canada
| | - Peter A Cadieux
- Department of Microbiology and Immunology, Western University, London, Ontario, Canada.,School of Health Sciences, Fanshawe College, London, Ontario, Canada
| | - John D Denstedt
- Department of Surgery, Division of Urology, Western University, London, Ontario, Canada
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Kallidonis PS, Georgiopoulos IS, Kyriazis ID, Al-Aown AM, Liatsikos EN. Drug-eluting metallic stents in urology. Indian J Urol 2014; 30:8-12. [PMID: 24497674 PMCID: PMC3897059 DOI: 10.4103/0970-1591.124198] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Drugeluting metal stents (DESs) have been extensively used in coronary and vascular disease. This type of stents has been proven to provide significantly lower restenosis rates due to the reduction of neo-intimal hyperplasia in comparison to the traditionally used bare metal stents (BMSs). The latter stents have been evaluated for more than a decade in urological practice in an attempt to provide permanent relief of urethral or ureteral obstruction. Although the initial results were promising, long-term experience revealed significant complications, which are mainly attributed to stent-related hyperplastic reaction compromising stent patency. The favorable experience of vascular DESs led to the application of DESs in both the urethra and ureter of animal models. These experimental results demonstrated a reduction of hyperplastic reaction of DESs in comparison to BMSs. Nevertheless, clinical data are currently not available. Considering the fact that DESs are under continuous development, the use of DESs in urology holds promise for the future and seems to be an intriguing field.
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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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Liatsikos E, Kallidonis P, Stolzenburg JU, Karnabatidis D. Ureteral stents: past, present and future. Expert Rev Med Devices 2014; 6:313-24. [DOI: 10.1586/erd.09.5] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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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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Non-vascular drug eluting stents as localized controlled drug delivery platform: Preclinical and clinical experience. J Control Release 2013; 172:105-117. [DOI: 10.1016/j.jconrel.2013.08.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 08/03/2013] [Accepted: 08/05/2013] [Indexed: 01/10/2023]
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Della Maggiore AM, Steffey MA, Westropp JL. Treatment of traumatic penile urethral stricture in a dog with a self-expanding, covered nitinol stent. J Am Vet Med Assoc 2013; 242:1117-21. [PMID: 23547676 DOI: 10.2460/javma.242.8.1117] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
CASE DESCRIPTION An 8-month-old castrated male mixed-breed dog was evaluated because of hematuria, stranguria, and dysuria of approximately 2 weeks' duration that developed immediately following elective castration. CLINICAL FINDINGS Results of physical examination, ultrasonography, retrograde double-contrast cystourethrography, and urethroscopy were consistent with a traumatic urethral stricture immediately proximal to the os penis resulting in a partial obstruction of urine outflow. Results of ultrasonographic examination of abdominal organs were considered normal. Digital radiography revealed no evidence of calculi. TREATMENT AND OUTCOME Balloon dilation of the urethral stricture was performed and was followed by 2 bougienage procedures during the subsequent 2 weeks when clinical signs returned. The owners declined scrotal urethrostomy, and a self-expanding, covered nitinol stent was placed approximately 3 weeks after the initial evaluation, resulting in amelioration of clinical signs. Results of follow-up urethroscopy and contrast cystourethrography 1 year after stent placement revealed a statically positioned, patent urethral stent, although a small number of polypoid mucosal structures were identified distal to the stent and 1 small structure consistent with tissue ingrowth into the stent was identified. CLINICAL RELEVANCE Placement of a covered nitinol stent resulted in long-term resolution of clinical signs associated with traumatic stricture of the penile urethra in this young dog. Because the os penis in dogs limits radial expansion of the urethra, its presence may limit the use of stents in this location.
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Affiliation(s)
- Ann-Marie Della Maggiore
- Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616, USA
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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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Yuk SH, Oh KS, Park J, Kim SJ, Kim JH, Kwon IK. Paclitaxel-loaded poly(lactide-co-glycolide)/poly(ethylene vinyl acetate) composite for stent coating by ultrasonic atomizing spray. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2012; 13:025005. [PMID: 27877483 PMCID: PMC5090633 DOI: 10.1088/1468-6996/13/2/025005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 04/03/2012] [Accepted: 02/12/2012] [Indexed: 06/06/2023]
Abstract
The mixture of poly(lactide-co-glycolide) (PLGA) and poly(ethylene vinyl acetate) (PEVA) forms a homogeneous liquid in an organic solvent such as tetrahydrofuran, and a phase-separated PLGA/PEVA composite can be prepared from it by evaporating the organic solvent. Exploiting this phenomenon, we designed a novel method of preparing a drug-loaded PLGA/PEVA composite and used it for coating drug-eluting stents (DESs). Paclitaxel (PTX), an anticancer drug, was chosen as a model drug. PLGA acts as a microdepot for PTX, and PEVA provides mechanical strength to the coating material. The presence of PLGA in the PLGA/PEVA composite suppressed PTX crystallization in the coating material, and PTX showed a sustained release rate over more than 30 days. The mechanical strength of the PLGA/PEVA composite was better than that of PEVA used as a control. After coating the stent with a PLGA/PEVA composite using ultrasonic atomizing spray, the morphology of the coated material was observed by scanning electron microscopy, and the release pattern of PTX was measured by high-performance liquid chromatography.
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Affiliation(s)
- Soon Hong Yuk
- College of Pharmacy, Korea University, Jochiwon, Yeongi, Chungnam, 339–700, Korea
| | - Keun Sang Oh
- Biomedical Research Center, Korea Institute of Science and Technology, Seoul, 136–791, Korea
| | - Jinah Park
- College of Pharmacy, Korea University, Jochiwon, Yeongi, Chungnam, 339–700, Korea
| | - Soon-Joong Kim
- Department of Maxillofacial Biomedical Engineering, School of Dentistry, Kyung Hee University, 136–791, Korea
| | - Jung Ho Kim
- Department of Maxillofacial Biomedical Engineering, School of Dentistry, Kyung Hee University, 136–791, Korea
| | - Il Keun Kwon
- Department of Maxillofacial Biomedical Engineering, School of Dentistry, Kyung Hee University, 136–791, Korea
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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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Shin MS, Hong JY, Park S. Gemcitabine release behavior of polyurethane matrixes designed for local anti-cancer drug delivery via stent. J Drug Deliv Sci Technol 2012. [DOI: 10.1016/s1773-2247(12)50050-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Al-Aown A, Kyriazis I, Kallidonis P, Kraniotis P, Rigopoulos C, Karnabatidis D, Petsas T, Liatsikos E. Ureteral stents: new ideas, new designs. Ther Adv Urol 2011; 2:85-92. [PMID: 21789086 DOI: 10.1177/1756287210370699] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Ureteral stents represent a minimally invasive alternative to preserve urinary drainage whenever ureteral patency is deteriorated or is under a significant risk to be occluded due to extrinsic or intrinsic etiologies. The ideal stent that would combine perfect long-term efficacy with no stent-related morbidity is still lacking and stent usage is associated with several adverse effects that limit its value as a tool for long-term urinary drainage. Several new ideas on stent design, composition material and stent coating currently under evaluation, foreseen to eliminate the aforementioned drawbacks of ureteral stent usage. In this article we review the currently applied novel ideas and new designs of ureteral stents. Moreover, we evaluate potential future prospects of ureteral stent development adopted mostly by the pioneering cardiovascular stent industry, focusing, however, on the differences between ureteral and endothelial tissue.
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Song TJ, Lee SS, Yun SC, Park DH, Seo DW, Lee SK, Kim MH. Paclitaxel-eluting covered metal stents versus covered metal stents for distal malignant biliary obstruction: a prospective comparative pilot study. Gastrointest Endosc 2011; 73:727-33. [PMID: 21288514 DOI: 10.1016/j.gie.2010.11.048] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2010] [Accepted: 11/29/2010] [Indexed: 02/08/2023]
Abstract
BACKGROUND In unresectable malignant biliary obstruction, stent insertion can be the treatment of choice. However, metal stents are susceptible to occlusion by tumor ingrowth or overgrowth. The recently introduced paclitaxel-eluting covered metal stents (PECMSs) may prevent occlusion from tumor ingrowth by the antitumor effect of paclitaxel. OBJECTIVE Our goal was to compare the efficacy and complication rates of PECMSs and the control covered metal stents (CCMSs) in patients with malignant biliary obstruction. DESIGN Prospective, randomized pilot study. SETTING Single tertiary referral center. PATIENTS From November 2006 to June 2008, 52 patients with unresectable distal malignant biliary obstruction were enrolled. A PECMS was inserted in 26 patients and a CCMS in 26 patients. Of these patients, 2 patients in the PECMS group and 1 patient in the CCMS group were excluded. Finally 49 patients (24 patients in the PECMS group and 25 patients in the CCMS group) were included in the analysis. INTERVENTIONS PECMSs and CCMSs were inserted by using the standard ERCP technique. RESULTS The mean follow-up period was 194.0 ± 144.2 days in the PECMS group and 238.8 ± 147.4 days in the CCMS group (P = .287). The stent patency duration and survival time were not significantly different between the 2 groups (P = .307 and P = .596, respectively). Stent occlusion caused by tumor ingrowth occurred in 5 patients in the PECMS group. In the CCMS group, stent occlusion caused by tumor ingrowth (n = 4) or distal stent migration (n = 4) occurred in 8 patients. In the PECMS group, 3 cases of transient cholangitis-like symptoms without stent occlusion and 1 case of pancreatitis occurred after stent insertion. One patient in the CCMS group experienced pancreatitis. LIMITATIONS This study was a pilot study in which no power calculation was done. It was performed at a single center and was performed in a nonblinded fashion. CONCLUSIONS PECMSs may be safe with acceptable complication rates. There were no significant differences in the duration of stent patency and patient survival time between PECMSs and CCMSs in patients with distal malignant biliary obstruction. However, a larger study powered to detect differences must be done to conclude that there is any benefit of PECMSs.
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Affiliation(s)
- Tae Jun Song
- Department of Internal Medicine, Inje University Ilsanpaik Hospital, Koyang, South Korea
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Will TA, Polcari AJ, Garcia JG, Ouwenga MK, Voelzke BB, Greisler HP, Turk TMT. Paclitaxel inhibits ureteral smooth muscle cell proliferation and collagen production in the absence of cell toxicity. J Urol 2011; 185:335-40. [PMID: 21075396 DOI: 10.1016/j.juro.2010.09.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Indexed: 11/28/2022]
Abstract
PURPOSE Urinary tract stricture results from excess collagen deposition at an injured area. Paclitaxel (Sigma-Aldrich®) prevents coronary artery restenosis by inhibiting vascular smooth muscle cell proliferation and collagen production. We evaluated the effects of paclitaxel on ureteral smooth muscle cell proliferation and collagen production. MATERIALS AND METHODS Three phases of experiments were done in canine smooth muscle cells. In phase 1 we used proliferation assay to study smooth muscle cells exposed to various concentrations of paclitaxel during 7 days. Phase 2 consisted of 6-day enzyme-linked immunosorbent assay to detect the total amount of type III collagen produced by smooth muscle cells exposed to paclitaxel. In phase 3 we assessed smooth muscle cell membrane damage using a lactate dehydrogenase cytotoxicity assay in which cells were exposed to escalating paclitaxel concentrations for 14 days. RESULTS Proliferation studies showed that 10 and 100 nM paclitaxel significantly inhibited ureteral smooth muscle cell proliferation. Enzyme-linked immunosorbent assay revealed significantly decreased type III collagen production at 100 nM. Cytotoxicity testing showed that 1 to 100 nM paclitaxel did not harm smooth muscle cells. CONCLUSIONS Paclitaxel effectively inhibits canine ureteral smooth muscle cell proliferation and collagen production without toxicity to smooth muscle cells at concentrations up to 100 nM. These results may ultimately translate into new methods of preventing and treating urinary stricture disease.
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Affiliation(s)
- Thomas A Will
- Department of Urology, Loyola University Medical Center, Maywood, Illinois, USA
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Wang ZX, Hong BF, Xu Zhang, Fu WJ, Cui FZ, Kun Hu. New biodegradable drug-eluting stents for urethral strictures in a rabbit model. J BIOACT COMPAT POL 2010. [DOI: 10.1177/0883911510391452] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In this study, the feasibility and the effect of a new biodegradable drug-eluting urethral stents for the treatment of urethral stricture in a rabbit model were evaluated, and the biocompatibility properties of the new biodegradable drug-eluting urethral stents in the rabbit urethral assessed. A total of 34 male New Zealand White rabbits with urethral strictures were used, and equally divided into two groups: with drug stents and drug-free stents. The urethral strictures were made by using a self-control explosion device as the control. Stents were surgically implanted into the stenotic urethras of rabbits under direct vision. Reparative effects, including biocompatibility assessment, were evaluated by urethroscopy, retrograde urethrography, and histology at different intervals at weeks 4, 8, and 12. Although retrograde urethrography and urodynamic results at 12 weeks showed no comparable differences among the three groups, urethroscopic and histological follow-up indicated that the drug stents had minimized the stent-related inflammatory responses, urothelial hyperplasia, and scar formation compared with the drug-free stents. The new biodegradable paclitaxel-eluting stents were more biocompatible and effective for treating urethral strictures in the rabbit model than the drug-free stents.
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Affiliation(s)
- Zhong-Xin Wang
- Department of Urology, Chinese People's Liberation Army General Hospital, Military Postgraduate Medical College, No. 28 Fuxing Road, Hai dian District, Beijing 100853, People's Republic of China
| | - Bao-Fa Hong
- Department of Urology, Chinese People's Liberation Army General Hospital, Military Postgraduate Medical College, No. 28 Fuxing Road, Hai dian District, Beijing 100853, People's Republic of China
| | - Xu Zhang
- Department of Urology, Chinese People's Liberation Army General Hospital, Military Postgraduate Medical College, No. 28 Fuxing Road, Hai dian District, Beijing 100853, People's Republic of China
| | - Wei-Jun Fu
- Department of Urology, Chinese People's Liberation Army General Hospital, Military Postgraduate Medical College, No. 28 Fuxing Road, Hai dian District, Beijing 100853, People's Republic of China,
| | - Fu-Zhai Cui
- Advanced Materials Laboratory, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, People's Republic of China
| | - Kun Hu
- Advanced Materials Laboratory, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, People's Republic of China
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Evaluation of Formation of Granulation Tissue Caused by Metallic Stent Placement in a Rat Urethral Model. J Vasc Interv Radiol 2010; 21:1884-90. [DOI: 10.1016/j.jvir.2010.07.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Revised: 03/19/2010] [Accepted: 07/14/2010] [Indexed: 11/19/2022] Open
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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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Choi R, Lee S, Hyun C. Urethral stenting in a cat with refractory obstructive feline lower urinary tract disease. J Vet Med Sci 2009; 71:1255-9. [PMID: 19801911 DOI: 10.1292/jvms.71.1255] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A 10-year-old male Korean domestic short-haired cat was presented with refractory lower urinary tract obstruction. The cat was treated by urethral stent placement using a self-expanding nitinol intraluminal stent (Zilver 535 biliary stents, COOK, U.S.A.) subsequent with balloon expansion. Although the cat showed 2 days of transient hematuria after the stent placement, no further obstruction was occurred after the stent placement. Follow-up studies performed at monthly intervals have found no re-stenosis or particular complications, to date.
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Affiliation(s)
- Ran Choi
- Section of Small Animal Internal Medicine, School of Veterinary Medicine, Kangwon National University, Chuncheon, South Korea
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Lee SS, Shin JH, Han JM, Cho CH, Kim MH, Lee SK, Kim JH, Kim KR, Shin KM, Won YH, Song HY. Histologic influence of paclitaxel-eluting covered metallic stents in a canine biliary model. Gastrointest Endosc 2009; 69:1140-7. [PMID: 19243763 DOI: 10.1016/j.gie.2008.08.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2008] [Accepted: 08/02/2008] [Indexed: 02/08/2023]
Abstract
BACKGROUND Metallic stents for malignant biliary obstruction are susceptible to occlusion by tumor ingrowth or overgrowth. Paclitaxel-eluting metallic stents (PEMSs), however, may prevent occlusion from tumor ingrowth. OBJECTIVE We evaluated the safety of PEMSs in a canine biliary model by analyzing tissue reactions by histologic examination. DESIGN Animal study. SETTING AND INTERVENTIONS Six PEMSs and 5 control stents (CSs) were endoscopically placed in the bile ducts of 11 mongrel dogs and followed up for 6 weeks. MAIN OUTCOME MEASUREMENTS The animals were euthanized at 6 weeks, and gross and microhistologic examinations were done. A comparison was made between dogs with PEMSs and dogs with CSs. RESULTS All 11 stents were successfully placed in the bile ducts, although the distal ends of 2 PEMSs were partially exposed to the duodenal lumen. All 11 dogs survived until death without evidence of jaundice. Gross histologic examination showed mucosal hyperplasia in 3 of 6 dogs in the PEMS group, but there was no evidence of mucosal hyperplasia in the CS group. Microscopically, the epithelial layers at the middle and distal ends of the stented segments were significantly thicker in the PEMS dogs than in the CS group. CONCLUSIONS Placement of PEMSs in normal canine bile ducts was without significant technical complications; however, local drug delivery from the PEMS resulted in significant histologic changes. Therefore, it is important to choose a drug in adequate concentrations to exert an antitumor effect without damaging the adjacent normal bilary mucosa.
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Affiliation(s)
- Sang Soo Lee
- Department of Internal Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul
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SHIN JH, LEE SK, SONG HYO, KIM JS, CHOE H, KIM EH, LEE IJ, KIM TH, KIM EY, WOO CW, HOON NAH K. The effects of188rhenium-filled balloon dilation following bare stent placement in a rabbit oesophageal model. Br J Radiol 2008; 81:413-21. [DOI: 10.1259/bjr/25340112] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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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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Fu WJ, Zhang BH, Gao JP, Hong BF, Zhang L, Yang Y, Meng B, Zhu N, Cui FZ. Biodegradable urethral stent in the treatment of post-traumatic urethral strictures in a war wound rabbit urethral model. Biomed Mater 2007; 2:263-8. [DOI: 10.1088/1748-6041/2/4/009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Suk KT, Kim JW, Kim HS, Baik SK, Oh SJ, Lee SJ, Kim HG, Lee DH, Won YH, Lee DK. Human application of a metallic stent covered with a paclitaxel-incorporated membrane for malignant biliary obstruction: multicenter pilot study. Gastrointest Endosc 2007; 66:798-803. [PMID: 17905025 DOI: 10.1016/j.gie.2007.05.037] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2006] [Accepted: 05/16/2007] [Indexed: 02/08/2023]
Abstract
BACKGROUND Paclitaxel, with its antitumor effect, may improve the function of metallic stents used for biliary drainage. However, clinical studies that use metallic stents covered with a paclitaxel-incorporated membrane (MSCPM) in the biliary tract of human beings have not been previously carried out. OBJECTIVE To evaluate the safety and efficacy of an MSCPM for patients with malignant biliary obstruction. DESIGN AND SETTING A case series that includes 4 endoscopy centers. PATIENTS From July 2003 to August 2006, a total of 21 patients diagnosed with unresectable malignant biliary obstruction. INTERVENTION Endoscopic placement of an MSCPM. MAIN OUTCOME MEASUREMENTS Stent occlusion, complications, stent patency, patient survival, and the periodic mean concentration of paclitaxel in the blood. RESULTS Occlusion of the MSCPM was observed in 9 patients and was caused by bile sludge or clog in 4, tumor overgrowth in 3, and tumor ingrowth in 2. Complications included obstructive jaundice in 6, cholangitis in 3, and 1 patient showed stent migration with cholecystitis. The mean patency of a MSCPM was 429 days (median 270 days, range 68-810 days) and cumulative patency rates at 3, 6, and 12 months were 100%, 71%, and 36%, respectively. The mean survival of patients was 350 days (median 281 days, range 68-811 days). The highest concentration of paclitaxel in the blood was found between 1 and 10 days after insertion. LIMITATIONS Small number of patients and low rate of pathologic diagnosis. CONCLUSIONS The endoscopic insertion of MSCPM is technically feasible, safe, and effective in patients with malignant biliary obstruction. In addition, MSCPM may exert local antitumor activity because of the steady release of paclitaxel.
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Affiliation(s)
- Ki Tae Suk
- Division of Gastroenterology, Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju, South Korea
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Kim KR, Song HY, Shin JH, Kim JH, Choi EK, Lee YJ. Efficacy of mitomycin C irrigation after removal of an occluded nasolacrimal stent. J Vasc Interv Radiol 2007; 18:519-25. [PMID: 17446543 DOI: 10.1016/j.jvir.2007.01.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
PURPOSE Mitomycin C (MMC) acts as a potent fibroblastic inhibitor, and topical application of MMC is effective in preventing scar formation. The purpose of this study was to evaluate the safety and efficacy of MMC irrigation after removal of an occluded nasolacrimal stent from the lacrimal system. MATERIALS AND METHODS A total of 57 lacrimal systems after removal of an occluded stent were assigned to one of two groups: 23 lacrimal systems were irrigated with MMC after stent removal (MMC group), and 34 lacrimal systems were not irrigated with MMC after stent removal (non-MMC group). In the MMC group, the lacrimal systems were irrigated with 0.2 mg/mL MMC through the inferior lacrimal punctum for 3 minutes in three different sessions: immediately, 1 week, and 1 month after stent removal. The mean and cumulative patency rates after stent removal were calculated using the Kaplan-Meier method and were compared between the two groups using the log-rank test. RESULTS Stent removal and MMC irrigation were technically successful in all lacrimal systems. There were no side effects or complications associated with MMC use. The mean patency rate after stent removal was higher in the MMC group than that of the non-MMC group: 10.5 months (95% CI: 7.04, 13.91) versus 4.5 months (95% CI: 2.40, 6.63), respectively. There was a statistically significant difference in the cumulative patency rates after stent removal between the two groups (P = .005, log-rank test). CONCLUSIONS Mitomycin C irrigation is safe and effective in increasing patency rate of lacrimal systems after removal of an occluded nasolacrimal stent.
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Affiliation(s)
- Kyung Rae 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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Liatsikos EN, Karnabatidis D, Kagadis GC, Rokkas K, Constantinides C, Christeas N, Flaris N, Voudoukis T, Scopa CD, Perimenis P, Filos KS, Nikiforidis GC, Stolzenburg JU, Siablis D. Application of Paclitaxel-Eluting Metal Mesh Stents within the Pig Ureter: An Experimental Study. Eur Urol 2007; 51:217-23. [PMID: 16814926 DOI: 10.1016/j.eururo.2006.05.054] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2006] [Accepted: 05/31/2006] [Indexed: 10/24/2022]
Abstract
OBJECTIVE The purpose of the present study is to compare the standard bare metal stents (BMS) with the Paclitaxel-Drug Eluting Stent (DES) in the ureter of a pig model. MATERIALS AND METHODS We report on an experimental study with ten female pigs weighing between 25 and 30 kg. The stents were randomly placed in either the right or left ureter in each of 10 study animals, for a total of 20 stented ureters. Ten ureters were stented with an R-Stent (Orbus Medical Technologies, Hoevelaken Netherlands), and ten with a Paclitaxel-Eluting Coronary Stent (Boston Scientific, Natick, MA, USA). Patency was measured by radiograph of the nephrostomy tract, intravenous urography and virtual endoscopy at 24 hours and 21 days after the initial procedure, respectively. RESULTS Free flow of urine through the stents into the bladder was documented in all stented ureters 24 hours after stent insertion by radiograph of the nephrostomy tract. At the 21 day follow-up examination, 5 R-Stents were found to be completely occluded and two partially stenosed, whereas no occluded stent was detected in the Paclitaxel-DES group. Pathology examination of the stents at 21 days follow-up showed that the obstructed R-Stents generated severe inflammation with metaplasia of the urothelium. The Paclitaxel-Eluting MS generated a mild inflammatory response within the ureteral lumen at the site of the stent, without hindering ureteral patency. R-stents proved to develop more hyperplasia compared to the Paclitaxel-Eluting MS. CONCLUSIONS Paclitaxel-DES, when compared with the standard R- Stent BMS, generated less inflammation and/or hyperplasia of the surrounding tissues, thus maintaining ureteral patency. Long-term animal trials are required to further validate our results.
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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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Weisse C, Berent A, Todd K, Clifford C, Solomon J. Evaluation of palliative stenting for management of malignant urethral obstructions in dogs. J Am Vet Med Assoc 2006; 229:226-34. [PMID: 16842042 DOI: 10.2460/javma.229.2.226] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To evaluate use of balloon-expandable and self-expanding metallic stents in management of malignant urethral obstructions in dogs. DESIGN Original study. ANIMALS 12 dogs with malignant urethral obstructions. PROCEDURES The extent and location of urethral obstructions and the diameter of adjacent unaffected luminal segments were determined by use of fluoroscopically guided wires and measuring catheters. Stents were chosen to extend approximately 1 cm proximal and distal to the obstruction. Stent diameters were chosen to be approximately 10% greater than the diameter of healthy portions of the urethra to prevent displacement. Stents were placed in the urethra under fluoroscopic guidance to restore luminal patency. RESULTS 3 dogs received balloon-expandable metallic stents, and 9 dogs received self-expanding metallic stents. The placement procedures were rapid, safe, and effective at restoring luminal patency and were not associated with major complications. Complications included recurrent urethral obstruction secondary to blood clot formation and urethral edema in 1 dog and stent dislodgement into the urinary bladder in 1 dog. All dogs were able to urinate immediately after the procedure. Nine dogs (3/4 females and 6/8 males) were continent or mildly incontinent after stent placement. Of the remaining 3 dogs, 2 developed severe incontinence and 1 had an atonic bladder. Seven dogs were considered to have good to excellent outcome, 3 had fair outcome, and 2 had poor outcome. CONCLUSIONS AND CLINICAL RELEVANCE Transurethral placement of metallic stents was a safe and effective palliative treatment option for dogs with malignant urethral obstructions.
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Affiliation(s)
- Chick Weisse
- Section of Small Animal Surgery, Department of Clinical Studies-Philadelphia, University of Pennsylvania, 19104-6010, USA
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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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Literature Alerts. Drug Deliv 2005. [DOI: 10.1080/10717540500201502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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