Nitinol urethral stents: long-term results in dogs

Latal, D; Mráz, J; Zerhau, Pavel; Susani, Martin; Marberger, Michael

doi:10.1007/bf00297198

Cited by 36 publications

(30 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…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%

“…In this study we used the SEMS type with balloon expansion to overcome the limitation of BEMS. One recent study found that SEMSs placed in the urethra of 18 healthy German Shepherds caused no superficial corrosion, infections, dislocations, encrustations, stone formations, or foreign body reactions for 18 months, although progressive pseudopoly- pous mucosal hyperplasia developed over the stent surface in histopathological examinations [11,18]. Another study using polyurethane covered wire stents with paclitaxel-eluting coatings found much favorable clinical outcome in dogs [11,17].…”

mentioning

confidence: 99%

“…One recent study found that SEMSs placed in the urethra of 18 healthy German Shepherds caused no superficial corrosion, infections, dislocations, encrustations, stone formations, or foreign body reactions for 18 months, although progressive pseudopoly- pous mucosal hyperplasia developed over the stent surface in histopathological examinations [11,18]. 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].…”

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%

“…One canine study used the stent approximately 10% greater than the maximum luminal diameter to ensure adequate mucosal apposition, minimize the chance of migration, and reduce trauma to the urethral wall. Another canine study suggested that the unconstrained stent diameter should not exceed 1.3 times the diameter of the prostatic portion of the urethra [4,11,16,17]. Also one canine study suggested the stent length to be chosen with the objective of reestablishing urethral patency while minimizing stenting of the adjacent healthy urethra [17].…”

mentioning

confidence: 99%

See 4 more Smart Citations

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

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

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

show abstract

In vivo biocompatibility evaluation of nickel-titanium shape memory metal alloy: Muscle and perineural tissue responses and encapsule membrane thickness

Ryhänen

Kallioinen

Tuukkanen

et al. 1998

J. Biomed. Mater. Res.

167

View full text Add to dashboard Cite

Nickel-titanium shape memory alloy (Nitinol) has properties that could be very useful in surgical applications. Thermal shape memory, superelasticity, and high damping properties make such alloys behave differently compared to other implant metals. There has previously been a lack of sufficient evidence on the biocompatibility of Nitinol. The purpose of this study was to evaluate general soft tissue response and biocompatibility to Nitinol in vivo, and to clarify neural and perineural responses, previously unreported. Seventy-five rats were randomized into three groups. Test specimens were implanted into paravertebral muscle and near the sciatic nerve. A comparison was made between Nitinol, stainless steel, and Ti-6Al-4V. The animals were euthanized at 2, 4, 8, 12, and 26 weeks after implantation. General morphologic and histologic observations were made under light microscopy. Semiautomatic computerized image analysis was used to measure the encapsule membrane thickness around the implants. The muscular tissue response to Nitinol was clearly nontoxic, regardless of the time period. The overall inflammatory response to Nitinol was very similar to that of stainless steel and Ti-6Al-4V alloy. There were no necroses, granulomas, or signs of dystrophic soft tissue clacification. The immune cell response to Nitinol remained low. Only a few foreign-body giant cells were present. The detected neural and perineural responses were also clearly nontoxic and nonirritating with Nitinol. No qualitative differences in histology between the different test materials could be seen. At 8 weeks, the encapsule membrane of Nitinol was thicker than that of stainless steel (mean 62 +/- 25 microns vs. 41 +/- 8 microns). At the end of the study, the encapsule thickness was equal to all the materials tested. We concluded that Nitinol had good in vivo biocompatibility after intramuscular and perineural implantation in rats in the 26-week follow-up. Based on the results of the present study, Nitinol appears to have good potential for clinical use.

show abstract

Increased corrosion resistance of stent materials by converting current surface film of polycrystalline oxide into amorphous oxide

Shih

Lin

Chung

et al. 2000

J. Biomed. Mater. Res.

103

View full text Add to dashboard Cite

Current efforts of new stent technology have been aimed largely at the improvement of intravascular stent biocompatibility. Among the chemical characteristics of metallic stents, surface oxide corrosion properties are paramount. Using our unique technique, the currently marketed 316 L stainless steel and nitinol stent wires covered with polycrystalline oxide were chemically etched and then passivated to form amorphous oxide. Excellent metallic-stent corrosion resistance with an amorphous oxide surface was demonstrated in our previous in vitro study. For in vivo validation, we compared the corrosion behavior of different oxide surfaces on various forms of test wires in the abdominal aorta of mongrel dogs using open-circuit potential and cyclic anodic polarization measurements. After conduction, the retrieved test wires were observed under scanning electron microscope. No passivity breakdown was found for wires covered with amorphous oxide, while wires with polycrystalline oxide showed breakdown at potentials between +0.2 to + 0.6 V. It has been proven that severe pitting or crevice corrosion occurred on the surface of polycrystalline oxide, while the surface of amorphous oxide was free of degradations in our experiment. We have demonstrated that this amorphous oxide coating on metallic material provides better corrosion resistance, not only in vitro but also in vivo, and it is superior not only in strength safety but also in medical device biocompatibility.

show abstract

Nitinol urethral stents: long-term results in dogs

Cited by 36 publications

References 14 publications

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

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

In vivo biocompatibility evaluation of nickel-titanium shape memory metal alloy: Muscle and perineural tissue responses and encapsule membrane thickness

Increased corrosion resistance of stent materials by converting current surface film of polycrystalline oxide into amorphous oxide

Contact Info

Product

Resources

About