Covered, Retrievable, Expandable Urethral Nitinol Stent: Feasibility Study in Dogs

Ko, Gi Young; Kim, Gab Cheol; Seo, Tae Seok; Kim, Tae Hyung; Lim, Jin Oh; Lee, Jong Heon; Song, Ho Young

doi:10.1148/radiol.2231010734

Cited by 29 publications

(16 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In spite of this, we hasten to underscore our observation of resolution of stent-induced stenosis in all cases after stent removal. Of note, this pattern of normalization of hyperplastic tissue growth after stent removal has also been documented in cases of urethral strictures [23,24]. We thereby encourage a greater threshold of stent removal in cases of mild to moderate severity of tissue hyperproliferation only so long as the patient is capable of tolerating a soft diet and regular follow-up is possible.…”

Section: Discussionmentioning

confidence: 55%

Temporary metallic stent placement in the treatment of refractory benign esophageal strictures: results and factors associated with outcome in 55 patients

et al. 2008

Self Cite

View full text Add to dashboard Cite

The purpose of this study was to evaluate the effectiveness of temporary metallic stenting in 55 patients with treatment-resistant benign esophageal strictures and to identify factors associated with clinical outcomes. Under fluoroscopic guidance, covered retrievable stents were placed in 55 patients with benign esophageal strictures and were removed with retrieval hook 1 week to 6 months after placement. Stent placement was successful in all patients, and the mean dysphagia score was reduced from 2.8 to 1.3 (p<0.001). The most common complications were tissue hyperproliferation (31%), severe pain (24%), and stent migration (25%). During follow-up (mean: 38 months), recurrence of the stricture necessitating balloon dilation was seen in 38 (69%) of 55 patients. Maintained patency rates after temporary stenting at 1, 3, and 6 months and 1, 2, and 4 years were 58%, 43%, 38%, 33%, 26%, and 21%, respectively. In multivariate analysis, length (p=0.003) of the stricture was the only significant factor associated with maintained patency after temporary stenting. In conclusion, temporary metallic stenting for refractory benign esophageal strictures may be effective during the period of stent placement, but is disadvantaged by the high recurrence rates after stent removal, particularly in patients with a long length of stricture (>7 cm).

show abstract

Section: Discussionmentioning

confidence: 55%

Temporary metallic stent placement in the treatment of refractory benign esophageal strictures: results and factors associated with outcome in 55 patients

et al. 2008

Self Cite

View full text Add to dashboard Cite

show abstract

“…Both balloon-expandable (BEMSs) and self-expanding metallic stents (SEMSs) are generally used for relieving urinary obstruction in dogs [2,3,7,10,11,18,19]. The major advantage of BEMSs is lack of the foreshortening that occurs with some types of SEMSs, although BEMSs relatively lack flexibility and elasticity.…”

mentioning

confidence: 99%

“…Another study using polyurethane covered wire stents with paclitaxel-eluting coatings found much favorable clinical outcome in dogs [11,17]. Main complications associated with urethral stent placement in dogs are luminal re-stenosis by epithelia hyperplasia resulting from stent placement, re-obstruction resulting from either a blood clot or mucosal swelling and edema secondary to excessive balloon dilatation and presumptive urethral mucosa trauma or tearing and development of urinary incontinence resulting from the damage to urethral sphincter by stent placement [2,3,7,10,11,18,19]. Unfortunately, no concrete study related to urethral stent placement in cats has been conducted yet.…”

mentioning

confidence: 99%

Urethral Stenting in a Cat with Refractory Obstructive Feline Lower Urinary Tract Disease

Choi

Lee²,

Hyun

2009

The Journal of Veterinary Medical Science

View full text Add to dashboard Cite

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.KEY WORDS: feline, FLUTD, FUS, urethral obstruction, urethral stent.J. Vet. Med. Sci. 71(9): 1255-1259, 2009 Lower urinary tract disease (LUTD) in cats has numerous causes including infection, trauma, urolithiasis, urethral obstruction or neoplasia [1]. Unlike dogs however, the most frequent cause for haematuria and dysuria in cats is unknown. This has led to numerous terms such as feline urologic syndrome (FUS), feline interstitial cystitis (FIC; based on similarities with the human condition) and idiopathic feline lower urinary tract disease (iFLUTD) [8,16]. It is reported that 70% of non-obstructive LUTD is idiopathic and that 25% is due to cystoliths [6]. Obstructive causes of LUTD are usually intraluminal with the majority caused by urethral plugs rather than uroliths. Urethral plugs have large amounts of matrix and minerals (usually struvite) and any crystalline material is disorganized. The general features of urolithiasis are similar for cats and dogs although struvite uroliths in cats are less associated with bacterial infections [6,7].Although the successful treatment of iFLUTD is often achieved with the removal of dry diets, stress reduction and increased water supply after re-canalization with indwelling urethral catheterization and warm saline flushing [5,7]. However, iFLUTD often re-occurs and progresses to refractory iFLUTD, which requires perineal urethrostomy to permanently relieve recurrent obstructions in male cats [5,7]. However, there can be post-operative problems such as stricture, recurrent urinary tract infections and perineal hernias [8,16].Urethral stent placement using self-expanding metallic stents under fluoroscopic guidance is widely used in humans and dogs with urethral obstructions secondary to transitional and prostatic tumors [9,[12][13][14]. This technique has several advantages over conventional surgical methods, because it can be used to rapidly, safely, and effectively relieve urethral obstructions, especially in patients in which other traditional techniques have failed, are not available, or not indicated [18]. These techniques are minimally invasive and can therefore lead to reduced peri-operative morbidity and mortality, shorter anesthesia times and shorter hospital stays, although the expense for urethral stent placement is substantial. This case report described the clinical application of urethral stent in a cat with refractory urethral obstruction.A 10-year-old male Korean domestic short-haired cat (3.9 kg of body w...

show abstract

“…Although some authors reported that endoscopic or surgical removal of uncovered urethral stents were feasible [2, 4-6, 8, 9], removal failure and risk of incomplete removal or significant bleeding have occurred in cases of tight stent welding to the urethral wall [2,8]. In contrast, covered retrievable stents are not as affected by ingrowth of tissue hyperplasia into the stent wire mesh as far as the covering material is intact and are thus easily removed when no longer necessary or there are complications [10][11][12].…”

Section: Discussionmentioning

confidence: 99%

Removal of retrievable self-expandable urethral stents: experience in 58 stents

et al. 2006

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Covered, Retrievable, Expandable Urethral Nitinol Stent: Feasibility Study in Dogs

Abstract: Although some design modifications are necessary to reduce current complications, the polyurethane-covered retrievable nitinol stent seems feasible for use in the urethra. Stent-induced granulation tissue formation improved after stent removal.

Cited by 29 publications

References 25 publications

Temporary metallic stent placement in the treatment of refractory benign esophageal strictures: results and factors associated with outcome in 55 patients

Temporary metallic stent placement in the treatment of refractory benign esophageal strictures: results and factors associated with outcome in 55 patients

Urethral Stenting in a Cat with Refractory Obstructive Feline Lower Urinary Tract Disease

Removal of retrievable self-expandable urethral stents: experience in 58 stents

Contact Info

Product

Resources

About