nitinol and Tracheal-Diseases

The objective of this study was to assess tracheal reactivity after the deployment of different self-expandable metal stents (SEMS).. Forty female New Zealand rabbits were divided into four groups. Three groups received three different SEMS: steel (ST), nitinol (NiTi), or nitinol drug-eluting stent (DES); the fourth group was the control group (no stent). Stents were deployed percutaneously under fluoroscopic guidance. Animals were assessed by multi-slice, computed tomography (CT) scans, and tracheas were collected for anatomical pathology (AP) study. Data from CT and AP were statistically analyzed and correlated.. The DES group had the longest stenosis (20.51±14.08mm vs. 5.84±12.43 and 6.57±6.54mm in NiTi and ST, respectively, day 30; P<.05), and higher granuloma formation on CT (50% of cases). The NiTi group showed the lowest grade of stenosis (2.86±6.91% vs. 11.28±13.98 and 15.54±25.95% in DES and ST, respectively; P<.05). The AP study revealed that the ST group developed intense proliferative reactivity compared to the other groups. In the DES group, a destructive response was observed in 70% of the animals, while the NiTi was the least reactive stent. CT was more effective in detecting wall thickening (positive correlation of 68.9%; P<.001) than granuloma (not significant).. The ST group developed granulomas and significant stenosis. NiTi was the least reactive stent, while DES caused significant lesions that may be related to drug dosage. This type of DES stent is therefore not recommended for the treatment of tracheobronchial stenosis.

Topics: Alloys; Animals; Female; Fluoroscopy; Granuloma; Models, Animal; Multidetector Computed Tomography; Rabbits; Self Expandable Metallic Stents; Steel; Tracheal Diseases; Tracheal Stenosis

To report bronchoscopic placement of nitinol stents (Vet Stent-Trachea®) for improvement of end-stage clinical signs in dogs with tracheal collapse.. Case series.. Dogs (n = 18).. Medical records (January 1, 2004-October 31, 2008) were searched for dogs with a diagnosis of tracheal collapse; 18 dogs met inclusion criteria. Tracheal diameter was compared before and after stent deployment. Stent dimensions were compared after stent deployment and at radiographic follow-up.. There was a significant difference in the minimum tracheal diameter when initial and post deployment tracheal diameters were compared (P = .003). Stent length was significantly shorter at follow-up when compared to post deployment measurements (P = .004). Owner assessment of outcome was available for all dogs with 11.1% mortality within 60 days. Complications were documented in 9 dogs.. Use of a nitinol stent (Vet Stent-Trachea®) in dogs with end-stage tracheal collapse is associated with a fair to good outcome despite significant temporal stent fore shortening after bronchoscopic placement.

Topics: Alloys; Animals; Dog Diseases; Dogs; Female; Male; Prosthesis Implantation; Retrospective Studies; Stents; Tracheal Diseases; Tracheal Stenosis

To evaluate long-term outcome following nitinol stent placement in dogs with tracheal collapse.. Retrospective case series.. 12 client-owned dogs with endoscopically diagnosed tracheal collapse refractory to medical management.. Medical records were reviewed for 12 dogs in which 1 or more self-expanding nitinol stents were placed for the treatment of endoscopically diagnosed tracheal collapse. A total of 17 stents were placed.. Survival times after stent placement ranged from 1 to 48 months. Three of 12 dogs died within 6 months after stent placement. Nine dogs survived > 1 year after stent placement, and 7 dogs survived > 2 years. Of the deceased dogs, 5 of 9 succumbed to tracheal disease. Other causes of death included congestive heart failure, cerebral neoplasia, cerebrovascular accident, and renal failure. Material failure (stent fracture) was a common complication (5/12 dogs). Other complications reported included excessive granulation tissue within the stent lumen, tracheitis, and pneumonia.. Placement of an intraluminal stent with self-expanding nitinol stents was a successful palliative treatment for tracheal collapse in dogs that did not respond to medical management. Disease progression is inevitable, but substantial improvement in respiratory function may be achieved for a period of months to years.

Topics: Alloys; Animals; Disease Progression; Dog Diseases; Dogs; Female; Male; Prosthesis Implantation; Retrospective Studies; Stents; Survival Analysis; Time Factors; Tracheal Diseases; Treatment Outcome

Nitinol stents have been used in the treatment of benign tracheal stenosis. A retrospective review of five patients treated at Stobhill Hospital over the last six and a half years is presented. Age at presentation ranged from 17 to 76 years. The minimum follow-up period was 23 months and the maximum was 78 months. All our patients were successfully decannulated, with none requiring recannulation. Four patients developed granulation tissue related to the stent at intervals ranging from three weeks to 41 months post stenting. Topical mitomycin C application has been useful after resection of granulations using the carbon dioxide (CO2) laser. Stent migration occurred in one patient three weeks after insertion. Nitinol stents are easy to insert and effective in the treatment of tracheal stenosis, but can have associated morbidity. Their use should be considered carefully, as insertion should be regarded as permanent. Publications reporting experience and outcome with the use of Nitinol stents in the trachea are reviewed.

Topics: Administration, Topical; Adolescent; Adult; Aged; Alloys; Antibiotics, Antineoplastic; Cartilage Diseases; Female; Foreign-Body Migration; Granuloma, Foreign-Body; Humans; Laser Therapy; Male; Middle Aged; Mitomycin; Patient Satisfaction; Retrospective Studies; Stents; Tracheal Diseases; Tracheal Stenosis; Treatment Outcome

Three different internal airway stents were studied in an animal model of tracheomalacia: the Palmaz stent (Johnson & Johnson, Warren, New Jersey) and the NIR stent (Medinol Ltd., Tel Aviv, Israel)--both made of stainless steel in the form of tubular mesh--and the Nitinol stent, made of nickel-titanium formed into a spiral shape. All three stents could be adequately stabilized in the malacic tracheal segment. The Nitinol stent (Medinol Ltd., Tel Aviv, Israel) proved to be less reactive to the tracheal mucosa, demonstrated higher biocompatibility with significantly less granulation tissue formation, and showed superior radial resistance. Extraction of the Nitinol stent also proved to be much smoother. This stent may be the stent of choice in the treatment of tracheo- and bronchomalacia.

Topics: Airway Obstruction; Alloys; Animals; Bronchoscopy; Disease Models, Animal; Prosthesis Design; Stents; Swine; Trachea; Tracheal Diseases; Tracheal Stenosis

A 7-month-old miniature horse was referred for respiratory distress. Tracheal collapse at the level of the thoracic inlet was diagnosed. An intraluminal nitinol stent was placed with endoscopic guidance. Respiratory function was restored immediately after stent placement. The main complication observed during a 14-month follow-up period was growth of granulation tissue through the stent, which was controlled satisfactorily by electrocautery performed during endoscopy with the horse standing. Treatment of tracheal collapse with an intraluminal stent is an effective, practical, and minimally invasive procedure in miniature and young equids and ponies.

Topics: Alloys; Animals; Electrocoagulation; Endoscopy; Granulation Tissue; Horse Diseases; Horses; Minimally Invasive Surgical Procedures; Postoperative Complications; Prosthesis Implantation; Stents; Tracheal Diseases; Treatment Outcome

Topics: Aged; Alloys; Chronic Disease; Cough; Female; Humans; Stents; Tracheal Diseases

Temporary or permanent tracheal splinting in pediatric patients may be indicated in tracheomalacia or bronchomalacia, repair of congenital tracheal stenosis, and after tracheal resection. This study presents the results of the development of a new intraluminal airway stent made from titanium alloy, a metal with "shape memory effect". At low temperatures (martensitic state) the titanium alloy stent can be fashioned into a specific shape; then when heated to a higher temperature (austenitic state) the stent alters its shape, only to regain its original shape when recooled to the lower temperature. The stent, connected to a small electric power supply, was introduced into 20 young rabbits with the use of a 2.5 cm rigid bronchoscope. After implantation in the martensitic state the stent was warmed to 40 degrees C, the austenitic state, by an electric current of 1.5 to 3 ampere for 1 to 2 seconds. After a period of 8 to 10 weeks the stent was removed (in its martensitic state) through the same-sized bronchoscope after being cooled with 3 to 4 ml of 80% alcohol solution at 6 degrees C. No signs of airway obstruction developed in any of the animals after implantation or extraction of the stent. The biomechanical properties of the trachea, as shown by strain measurements with the use of incremental forces, showed significant differences between the stented and unstented segments (p < 0.005). The titanium alloy intratracheal stent adequately fulfilled the requirements of a temporary intraluminal airway splint, and because of its unique feature of shape memory effect the stent could be inserted, fixed, and removed easily, even in very small airways.

Topics: Alloys; Animals; Biomechanical Phenomena; Equipment Design; Rabbits; Stents; Temperature; Trachea; Tracheal Diseases; Tracheal Stenosis