The Experts below are selected from a list of 2589 Experts worldwide ranked by ideXlab platform
Kun Yung Kim - One of the best experts on this subject based on the ideXlab platform.
-
Balloon-Expandable Biodegradable Stents Versus Self-Expandable Metallic Stents: A Comparison Study of Stent-Induced Tissue Hyperplasia in the Rat Urethra
CardioVascular and Interventional Radiology, 2019Co-Authors: Jung Hoon Park, Young Chul Cho, Nader Bakheet, Seung Ok Lee, Seong Hun Kim, Tae Hyung Kim, Kun Yung KimAbstract:PurposeTo compare the degrees of Stent-induced tissue hyperplasia of balloon-expandable, Biodegradable Stents (BEBSs) with those of self-expandable metallic Stents (SEMSs) in a rat urethral model.Materials and MethodsA total of 20 rats were randomized into two groups. The BEBS group (n = 10) received a poly-l-lactic acid (PLLA) Biodegradable Stent. The SEMS group (n = 10) received a nitinol bare Stent. All rats were killed eight weeks after Stent placement. The degree of Stent-induced tissue hyperplasia was assessed by comparing the results of retrograde urethrography and histologic examination between the two groups.ResultsStent placement was technically successful in all rats. Two rats in the BEBS group were excluded due to procedure-related death. The mean luminal diameter of Stented urethra on urethrograms was not significantly different at 4 and 8 weeks between the two groups. On histologic analysis, the percentage of granulation tissue area (p
-
Balloon-Expandable Biodegradable Stents Versus Self-Expandable Metallic Stents: A Comparison Study of Stent-Induced Tissue Hyperplasia in the Rat Urethra
CardioVascular and Interventional Radiology, 2019Co-Authors: Jung Hoon Park, Young Chul Cho, Nader Bakheet, Seung Ok Lee, Seong Hun Kim, Tae Hyung Kim, Kun Yung KimAbstract:PurposeTo compare the degrees of Stent-induced tissue hyperplasia of balloon-expandable, Biodegradable Stents (BEBSs) with those of self-expandable metallic Stents (SEMSs) in a rat urethral model.Materials and MethodsA total of 20 rats were randomized into two groups. The BEBS group (n = 10) received a poly-l-lactic acid (PLLA) Biodegradable Stent. The SEMS group (n = 10) received a nitinol bare Stent. All rats were killed eight weeks after Stent placement. The degree of Stent-induced tissue hyperplasia was assessed by comparing the results of retrograde urethrography and histologic examination between the two groups.ResultsStent placement was technically successful in all rats. Two rats in the BEBS group were excluded due to procedure-related death. The mean luminal diameter of Stented urethra on urethrograms was not significantly different at 4 and 8 weeks between the two groups. On histologic analysis, the percentage of granulation tissue area (p
-
Balloon-Expandable Biodegradable Stents Versus Self-Expandable Metallic Stents: A Comparison Study of Stent-Induced Tissue Hyperplasia in the Rat Urethra.
Cardiovascular and interventional radiology, 2019Co-Authors: Jung Hoon Park, Young Chul Cho, Nader Bakheet, Seung Ok Lee, Seong Hun Kim, Tae Hyung Kim, Kun Yung KimAbstract:To compare the degrees of Stent-induced tissue hyperplasia of balloon-expandable, Biodegradable Stents (BEBSs) with those of self-expandable metallic Stents (SEMSs) in a rat urethral model. A total of 20 rats were randomized into two groups. The BEBS group (n = 10) received a poly-l-lactic acid (PLLA) Biodegradable Stent. The SEMS group (n = 10) received a nitinol bare Stent. All rats were killed eight weeks after Stent placement. The degree of Stent-induced tissue hyperplasia was assessed by comparing the results of retrograde urethrography and histologic examination between the two groups. Stent placement was technically successful in all rats. Two rats in the BEBS group were excluded due to procedure-related death. The mean luminal diameter of Stented urethra on urethrograms was not significantly different at 4 and 8 weeks between the two groups. On histologic analysis, the percentage of granulation tissue area (p
Jung Hoon Park - One of the best experts on this subject based on the ideXlab platform.
-
Balloon-Expandable Biodegradable Stents Versus Self-Expandable Metallic Stents: A Comparison Study of Stent-Induced Tissue Hyperplasia in the Rat Urethra
CardioVascular and Interventional Radiology, 2019Co-Authors: Jung Hoon Park, Young Chul Cho, Nader Bakheet, Seung Ok Lee, Seong Hun Kim, Tae Hyung Kim, Kun Yung KimAbstract:PurposeTo compare the degrees of Stent-induced tissue hyperplasia of balloon-expandable, Biodegradable Stents (BEBSs) with those of self-expandable metallic Stents (SEMSs) in a rat urethral model.Materials and MethodsA total of 20 rats were randomized into two groups. The BEBS group (n = 10) received a poly-l-lactic acid (PLLA) Biodegradable Stent. The SEMS group (n = 10) received a nitinol bare Stent. All rats were killed eight weeks after Stent placement. The degree of Stent-induced tissue hyperplasia was assessed by comparing the results of retrograde urethrography and histologic examination between the two groups.ResultsStent placement was technically successful in all rats. Two rats in the BEBS group were excluded due to procedure-related death. The mean luminal diameter of Stented urethra on urethrograms was not significantly different at 4 and 8 weeks between the two groups. On histologic analysis, the percentage of granulation tissue area (p
-
Balloon-Expandable Biodegradable Stents Versus Self-Expandable Metallic Stents: A Comparison Study of Stent-Induced Tissue Hyperplasia in the Rat Urethra
CardioVascular and Interventional Radiology, 2019Co-Authors: Jung Hoon Park, Young Chul Cho, Nader Bakheet, Seung Ok Lee, Seong Hun Kim, Tae Hyung Kim, Kun Yung KimAbstract:PurposeTo compare the degrees of Stent-induced tissue hyperplasia of balloon-expandable, Biodegradable Stents (BEBSs) with those of self-expandable metallic Stents (SEMSs) in a rat urethral model.Materials and MethodsA total of 20 rats were randomized into two groups. The BEBS group (n = 10) received a poly-l-lactic acid (PLLA) Biodegradable Stent. The SEMS group (n = 10) received a nitinol bare Stent. All rats were killed eight weeks after Stent placement. The degree of Stent-induced tissue hyperplasia was assessed by comparing the results of retrograde urethrography and histologic examination between the two groups.ResultsStent placement was technically successful in all rats. Two rats in the BEBS group were excluded due to procedure-related death. The mean luminal diameter of Stented urethra on urethrograms was not significantly different at 4 and 8 weeks between the two groups. On histologic analysis, the percentage of granulation tissue area (p
-
Balloon-Expandable Biodegradable Stents Versus Self-Expandable Metallic Stents: A Comparison Study of Stent-Induced Tissue Hyperplasia in the Rat Urethra.
Cardiovascular and interventional radiology, 2019Co-Authors: Jung Hoon Park, Young Chul Cho, Nader Bakheet, Seung Ok Lee, Seong Hun Kim, Tae Hyung Kim, Kun Yung KimAbstract:To compare the degrees of Stent-induced tissue hyperplasia of balloon-expandable, Biodegradable Stents (BEBSs) with those of self-expandable metallic Stents (SEMSs) in a rat urethral model. A total of 20 rats were randomized into two groups. The BEBS group (n = 10) received a poly-l-lactic acid (PLLA) Biodegradable Stent. The SEMS group (n = 10) received a nitinol bare Stent. All rats were killed eight weeks after Stent placement. The degree of Stent-induced tissue hyperplasia was assessed by comparing the results of retrograde urethrography and histologic examination between the two groups. Stent placement was technically successful in all rats. Two rats in the BEBS group were excluded due to procedure-related death. The mean luminal diameter of Stented urethra on urethrograms was not significantly different at 4 and 8 weeks between the two groups. On histologic analysis, the percentage of granulation tissue area (p
-
polydioxanone Biodegradable Stent placement in a canine urethral model analysis of inflammatory reaction and biodegradation
Journal of Vascular and Interventional Radiology, 2014Co-Authors: Jung Hoon Park, Young Chul Cho, Ho Young Song, Ji Hoon Shin, Jin Hyoung Kim, Eun Jung Jun, Soo Hwan Kim, Jihong ParkAbstract: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 ¼ 3), 8 weeks (group B; n ¼ 3), or 12 weeks (group C; n ¼ 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 o .001), the average thickness of papillary projection (0.80 mm vs 1.28 mm; P o .001), and the average thickness of submucosal fibrosis (0.34 mm vs 0.49 mm ; P o .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.
Jan M Macak - One of the best experts on this subject based on the ideXlab platform.
-
mechanical properties of a Biodegradable self expandable polydioxanone monofilament Stent in vitro force relaxation and its clinical relevance
PLOS ONE, 2020Co-Authors: Ales Bezrouk, Tomas Hosszu, Ludek Hromadko, Zuzana Zmrhalova, Martin Kopecek, Martin Smutny, Iva Selke Krulichova, Jan M MacakAbstract:Biodegradable Stents are promising treatments for many diseases, e.g., coronary artery disease, urethral diseases, tracheal diseases, and esophageal strictures. The mechanical properties of Biodegradable Stent materials play a key role in the safety and efficacy of treatment. In particular, insufficient creep resistance of the Stent material could result in premature Stent collapse or narrowing. Commercially available Biodegradable self-expandable SX-ELLA Stents made of polydioxanone monofilament were tested. A new, simple, and affordable method to measure the shear modulus of tiny viscoelastic wires is presented. The important mechanical parameters of the polydioxanone filament were obtained: the median Young's modulus was [Formula: see text] = 958 (922, 974) MPa and the shear modulus was [Formula: see text] = 357 (185, 387) MPa, resulting in a Poisson's ratio of ν = 0.34. The SX-ELLA Stents exhibited significant force relaxation due to the stress relaxation of the polydioxanone monofilament, approximately 19% and 36% 10 min and 48 h after Stent application, respectively. However, these results were expected, and the manufacturer and implanting clinician should be aware of the known behavior of these Biodegradable materials. If possible, a Biodegradable Stent should be designed considering therapeutic force rather than initial force. Additionally, new and more advanced Biodegradable shape-memory polymers should be considered for future study and use.
Fuzhai Cui - One of the best experts on this subject based on the ideXlab platform.
-
Biodegradable urethral Stent in the treatment of post-traumatic urethral strictures in a war wound rabbit urethral model.
Biomedical materials (Bristol England), 2007Co-Authors: Bing-hong Zhang, Bo Meng, Jiang-ping Gao, Bao-fa Hong, Lei Zhang, Yong Yang, Ning Zhu, Fuzhai CuiAbstract:To prevent terrorism during anti-terror war, we developed a reproducible animal model for the induction of a urethral stricture in a war wound rabbit, and to evaluate the feasibility and effect of using a Biodegradable urethral Stent in the prophylaxis and treatment of urethral strictures in a war wound (or traumatic) rabbit urethral model. The urethral stricture rabbit model was successfully performed by a self-control explosion destructor. New Biodegradable urethral Stents were placed in the urethras of 20 war wound (traumatic) rabbits, but no Stent was used in the 8 rabbits which formed the control group. Follow-up investigation included assessment of procedure success, Stent changes, urethrascopy and retrograde urethrography, and histological findings were obtained after sacrifice at 4, 6, 8 and 12 weeks after Stent placement. The urethral stricture model owing to a war wound (trauma) was tested by tissue reactions and urethroscopy. The length of the urethral strictures was 5–10 mm; the coarctatetion of the urethral lumen was more than 50%. Biodegradable Stent placement was technically successful in 20 rabbits. Urethral specimens obtained from the 4 week Stent placement group showed diminished inflammatory cell infiltration and decreased thickness of the papillary projections of the epithelium. There was a strong tendency towards regression of the papillary projections and regeneration of urethral mucosa epithelium in the 8 week group. In particular, the injured urethra has recovered completely in the Biodegradable Stent groups compared with the control group at 12 weeks. The Biodegradable urethral Stent seems feasible for treating and preventing urethral strictures owing to a war wound (or traumatic) urethra. There are distinct advantages in terms of safe, effective and less-invasive treatment for the reconstruction of post-traumatic urethral strictures.
Peter D Siersema - One of the best experts on this subject based on the ideXlab platform.
-
Biodegradable Stent placement before neoadjuvant chemoradiotherapy as a bridge to surgery in patients with locally advanced esophageal cancer
Gastrointestinal endoscopy, 2014Co-Authors: Maarten W. Van Den Berg, Frank P Vleggaar, Peter D Siersema, Daisy Walter, Paul Fockens, Elisabeth M.g. De Vries, Mark I. Van Berge Henegouwen, Richard Van Hillegersberg, Jeanin E. Van HooftAbstract:Dysphagia is the most common presenting symptom in patients with esophageal malignancy and contributes significantly to weight loss and malnourishment. An increasing number of patients with locally advanced esophageal cancer undergo treatment with neoadjuvant chemoradiotherapy (CRT) before surgery because this has been shown to improve survival. 1 Neoadjuvant CRT is, however, associated with acute inflammation and edema of the esophageal mucosa, which could increase symptoms of dysphagia and potentially further jeopardize nutritional status. 2 There are various options for nutritional support during neoadjuvant CRT,includingnasal-enteraltubefeeding,laparoscopic jejunostomy, and total parenteral nutrition. None of these options relieves dysphagia. Therefore, based on the good results of self-expandable Stent placement in the palliative setting, self-expandable Stents were introduced as a bridge to surgery during neoadjuvant treatment. Fully covered, self-expandable, metal and plastic Stents (FSEMS and FSEPS) have been used with good results, but this is at the expense of additional endoscopic procedures either toremoveamigratedStent ortoextract theStent before surgery. 3-6 In addition, SEMSs may hamper dose planning of radiotherapy because of backscatter on CT. 7 Recently, Biodegradable Stents have been developed to treat refractory benign esophageal strictures. 8,9 These Biodegradable Stents have the potential to refute the problems encountered with FSEMSs and FSEPSs; migration is less likely because the Stent is uncovered, and removal is not necessary because the Stent will be resolved at the time of esophagectomy. The aim of this study was to evaluate safety and efficacy of Biodegradable Stent placement before neoadjuvant CRT as bridge to surgery in patients with locally advanced esophageal cancer and dysphagia.
-
Biodegradable Stent placement in the esophagus
Expert review of medical devices, 2013Co-Authors: Petra G Van Boeckel, Frank P Vleggaar, Peter D SiersemaAbstract:Biodegradable Stents overcome some of the problems encountered with self-expanding metal Stents. They main advantage over self-expanding metal Stents is that endoscopic removal is not needed. Single Biodegradable Stents are often only temporarily effective in patients with a refractory benign esophageal stricture, as in the majority dysphagia recurs. If this occurs, sequential Biodegradable Stent placement may be an effective alternative to avoid the burden of serial dilations. In the future, it can be expected that (covered) Biodegradable Stents will be available to treat benign esophageal perforations/leaks, but also that they will be used for treating malignant indications combined with other (palliative) modalities, such as bridge to surgery or to maintain luminal patency during neoadjuvant chemoradiation.
-
combination of Biodegradable Stent placement and single dose brachytherapy is associated with an unacceptably high complication rate in the treatment of dysphagia from esophageal cancer
Gastrointestinal Endoscopy, 2012Co-Authors: Meike M. Hirdes, Frank P Vleggaar, Jeanin E Van Hooft, Harm K Wijrdeman, Maarten C C M Hulshof, Paul Fockens, O Reerink, Martijn G Van Oijen, Ingeborg Van Der Tweel, Peter D SiersemaAbstract:Background For the palliative treatment of dysphagia, esophageal Stent placement provides immediate improvement, whereas brachytherapy offers better long-term relief. Objective To evaluate safety and efficacy of concurrent brachytherapy and Biodegradable Stent placement. Design Prospective, single-arm study. Setting Two tertiary-care referral centers. Patients Nineteen consecutive patients with significant dysphagia resulting from unresectable esophageal cancer, with a life expectancy of more than 3 months. Intervention Single-dose brachytherapy (12 Gy) on day 1 followed by Biodegradable Stent placement on day 2. Main Outcome Measurements Intervention-related major complications (determined by an expert panel) and dysphagia. Results Nineteen patients (13 men, median age 66 years [interquartile range (IQR) 59-71] years) were included; 7 patients (37%) also received palliative chemotherapy. After inclusion of 19 patients, the study was ended prematurely because the safety threshold was exceeded. In total, 28 major complications occurred in 17 patients (89%). In 9 patients (47%), major complications were determined intervention-related (severe retrosternal pain with or without vomiting [n = 6], hematemesis [n = 1], recurrent dysphagia [n = 2]. Dysphagia scores decreased significantly from a median of 3 (IQR 3-4) to a median of 1 (IQR 0-3) after 1 month ( P Limitations Lack of routine endoscopy or contrast esophagram to evaluate recurrent dysphagia during follow-up. Conclusion Despite restoration of luminal patency, a combined treatment of brachytherapy and Biodegradable Stent placement cannot be recommended for the palliative treatment of esophageal cancer because of an unacceptably high intervention-related major complication rate.
-
Single and sequential Biodegradable Stent placement for refractory benign esophageal strictures: a prospective follow-up study.
Endoscopy, 2012Co-Authors: Meike M. Hirdes, Petra G Van Boeckel, Peter D Siersema, Frank P VleggaarAbstract:Background and study aim: Although Biodegradable Stents do not require removal, a single Biodegradable Stent may only temporarily relieve dysphagia in patients with refractory benign esophageal stricture (RBES). The aim of this study was to evaluate the safety and long term efficacy of single and sequential Biodegradable Stent placement in patients with RBES. Patients and methods: All patients who underwent Biodegradable Stent placement for RBES between August 2008 and March 2011 were prospectively followed to evaluate recurrent dysphagia and complication rates. Results: In total, 59 Stents were placed in 28 patients. Patients had previously been treated with multiple dilations (n = 20) or multiple dilations and non-Biodegradable esophageal Stenting (n = 8). A total of 13 patients underwent sequential Biodegradable Stent placement (median 3, range 2 – 8) during the study period. After initial Stent placement, the median dysphagia-free period was 90 days (range 14 – 618 days). Clinical success (absence of dysphagia ≥ 6 months after Stent placement) was achieved in seven patients (25 %) and major complications occurred in eight patients (29 %). After placement of a second Biodegradable Stent, the median dysphagia-free period was 55 days (range 25 – 700 days) and clinical success was achieved in 15 % of patients. After placement of a third Stent, the median dysphagia-free period was 106 days (range 90 – 150 days), but none of the patients was clinically dysphagia-free. Conclusion: Placement of a single Biodegradable Stent is only temporarily effective in the vast majority of patients with RBES treated in a tertiary referral center. Sequential Stenting may however be an option to avoid serial dilations.
-
a comparison of temporary self expanding plastic and Biodegradable Stents for refractory benign esophageal strictures
Clinical Gastroenterology and Hepatology, 2011Co-Authors: Petra G Van Boeckel, Frank P Vleggaar, Peter D SiersemaAbstract:Background & Aims It is a challenge to manage refractory benign esophageal strictures (RBES). We compared the efficacy and safety of self-expanding plastic Stents (SEPSs) with placement of Biodegradable Stents for the treatment of RBES. Methods We studied 2 groups of consecutive patients with RBES who received temporary placement (6 weeks) of SEPSs (n = 20) or Biodegradable Stents (n = 18). Data were collected with respect to clinical outcome, complications, recurrent dysphagia, and reinterventions. Results SEPSs were removed in 16 (80%) patients. Stent placement was not successful in 1 patient, while Stent removal was not performed in another 3 patients. Six (30%) patients with an SEPS were dysphagia-free after a median follow-up of 385 days (range, 77–924 days). Ten (50%) developed recurrent dysphagia. Major complications occurred in 2 patients (10%; 1 with hemorrhage and 1 with perforation). Six patients (33%) with a Biodegradable Stent were dysphagia-free after a median follow-up of 166 days (range 21–559 days) ( P = .83 compared with SEPS). Twelve patients (67%) had recurrent dysphagia. Major complications occurred in 4 patients (22%; 2 with hemorrhage, 2 with severe retrosternal pain) with a Biodegradable Stent ( P = .30 compared with SEPS). Reinterventions were less frequently indicated after biodegradeble Stent than after SEPS placement (15 [mean, 0.8 ± 0.6 per Stent placed] vs 21 [mean, 1.3 ± 0.4 per Stent placed], respectively; P = .03). Conclusions Placement of SEPSs or Biodegradable Stents provides long-term relief of dysphagia in 30% and 33%, respectively, of patients with RBES. Biodegradable Stents require fewer procedures than SEPSs, offering an advantage. Although Stent placement is a viable strategy in patients with RBES, the ideal strategy still needs to be defined.