Fracture of an endoluminal nitinol stent used in the treatment of tracheal collapse in a dog

A 5-year-old castrated male Pomeranian was evaluated because of severe dyspnea and coughing, and a diagnosis of complete, static collapse of the trachea at the thoracic inlet was made. After failure to improve with medical management alone, an endoluminal tracheal stent was placed, which resulted in resolution of signs. Ten weeks after stent placement, the dog underwent tracheal resection and anastomosis because the stent had fractured at the level of the thoracic inlet. One year after surgery, the dog was doing well and required treatment with hydrocodone infrequently. Compared with other surgical treatment options, placement of an endoluminal tracheal stent is a relatively noninvasive intervention that can provide effective relief from the clinical signs associated with tracheal collapse in dogs. Implantation of endoluminal tracheal stents may be associated with complications; therefore, the procedure may best be regarded as a salvage procedure for dogs with end-stage disease that are refractory to appropriate medical management, have extensive collapse of the intrathoracic portion of the trachea, or are poor candidates for surgery.     

Placement of intraluminal stents for treating tracheal collapse in dogs

Tracheal collapse is a progressive disease particularly of small breed dogs. In the terminal stage, when dyspnea becomes the dominating sign and is no longer manageable with medical treatment, a surgical procedure is necessary. With increasing frequency intraluminal tracheal stents are implanted minimal-invasively. In individual animals this is a lifesaving procedure, leading to immediate elimination of dyspnea. In most dogs cough for some time has to be anticipated as the stent acts as a foreign body, but severe complications like excessive formation of granulation tissue, stent migration or stent fracture are rare. Stents represent an attractive treatment modality for tracheal collapse in dogs with dyspnea.     

Self-expanding nitinol stents for the treatment of tracheal collapse in dogs: 12 cases (2001-2004)

OBJECTIVE: To evaluate long-term outcome following nitinol stent placement in dogs with tracheal collapse. DESIGN: Retrospective case series. ANIMALS: 12 client-owned dogs with endoscopically diagnosed tracheal collapse refractory to medical management. PROCEDURES: 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. RESULTS: 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. CONCLUSIONS AND CLINICAL RELEVANCE: 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.     

The use of intraluminal stents for tracheal collapse in two horses: Case management and long‐term treatment

Tracheal collapse is an uncommon clinical disorder in horses but when present can be difficult to correct. Various medical and surgical procedures to correct tracheal collapse have been described in horses with variable success. Recently, the use of an intraluminal stent has been described as a treatment for tracheal collapse in a miniature horse. The long‐term management, utilising intraluminal stents, in 2 miniature horses with tracheal collapse is presented here. In particular, various complications as a result of intraluminal stent placement are described, the most persistent being the formation of granulation tissue at various regions of the stents. Multiple methods of combating granulation tissue in this situation also are discussed.     

Noninvasive correction of a fractured endoluminal nitinol tracheal stent in a dog

An 11-year-old, castrated male Pomeranian was presented for intractable cough and dyspnea secondary to severe tracheal collapse. An endoluminal nitinol tracheal stent was placed with good results. Five months following placement of the prosthesis, clinical signs acutely recurred and failure of the implant was noted. A second stent was superimposed over the fractured stent and resulted in resolution of all clinical signs. The dog died several months later from progression of the tracheal collapse to the carina and mainstem bronchi.     

Treatment of tracheal collapse with an intraluminal stent in a miniature horse

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.     

Surgical management of atypical lateral tracheal collapse in a dog

A FOUR-year-old spayed miniature poodle was presented for evaluation because of a chronic cough which had been present from eight weeks of age. The condition had gradually worsened until exercise intolerance, inappetence and abdominal breathing occurred. The dog was thin and weighed only 1.5 kg. Auscultation revealed tachycardia, a normal respiratory rate and wheezing noises - more prominent on inspiration and localised to the cervical portion of the trachea. There was marked inspiratory and expiratory effort. Tracheal sensitivity was moderate and palpation induced a dry hacking cough. Radiography demonstrated mild thickening of the bronchial wall and pulmonary hyperinflation. Expiratory/inspiratory radiographs failed to demonstrate dynamic tracheal collapse. On fluroscopy, substantial changes in tracheal calibre were not apparent. Bronchoscopy was performed and the tracheal lumen was normal up to 12.5 cm from the incisors. At this point, there was lateral tracheal collapse to about 30 per cent. There was dynamic collapse with respiratory effort. The bronchoscope could be passed beyond the narrowing (consisting of five tracheal rings) to a trachea of normal size. No pathogens were found on tracheal lavage. Surgery was undertaken through a midline, ventral approach. Six specially made tracheal ring prostheses were individually inserted around the trachea and inside the recurrent laryngeal nerve. Each prosthesis was sutured in four places to the tracheal ring, to give external support. The dog improved clinically and 11 months after surgery, bronchoscopy was again performed. The trachea was narrowed to approximately 60 per cent but there was no dynamic collapse of the airway. Twenty-seven months after surgery the dog continued to lead a healthy active life.     

A case of tracheal collapse in the dog.

An eight-year-old male Yorkshire terrier which had had a cough for two years was presented and a diagnosis of tracheal collapse was made after examination with a bronchoscope. It was decided to try to correct the tracheal defect by plication. Two weeks after the operation the dog was examined under general anaesthesia. Although traction had exposed a part of the thoracic trachea it was not sufficient in this case to achieve a complete repair. In view of a grave prognosis, the dog was destroyed.     

Management of advanced tracheal collapse in dogs using intraluminal self-expanding biliary wallstents

Twenty-four client-owned dogs with tracheal collapse refractory to conventional treatment underwent management with an intraluminal self-expanding stainless-steel endoprosthesis (Wallstent). Initial improvement of clinical signs was observed in 95.8% of the dogs. Two dogs (8.3%) died within a median interval of 6 days after stent implantation due to incorrect placement and size of the stent and emphysema, respectively. A dry cough occurred temporarily in most of the patients. One dog each (4.1%) suffered mild transient tracheal hemorrhage and pneumomediastinum. The results showed that the initial survival rate of intraluminal stabilization was comparable with surgical implantation of extratracheal prostheses. Clinical reevaluation was performed in 18 dogs within a median interval of 68 days after treatment. Of the dogs treated, 30.4% were reported to be asymptomatic after stent implantation, 60.9% improved markedly, and 4.3% remained symptomatic. In all patients undergoing endoscopy, the Wallstents were almost completely covered with tracheal epithelium. A median shortening of 27.3% of the endoprosthesis within a median interval of 175 days after stent implantation in 15 of 18 dogs was noted. The shortening was associated with clinical signs in 2 patients. In 5 dogs, steroid-responsive granuloma formation resulted in a severe reduction of the tracheal lumen in 3 patients. The results suggest that implantation of Wallstents was minimally invasive and provided stabilization of collapsed thoracic tracheal portions in addition to the cervical part of the trachea. This minimally invasive method for the management of severe tracheal collapse therefore provides an attractive alternative to surgery.     

The Safety and efficacy of a new self-expandable intratracheal nitinol stent for the tracheal collapse in dogs

To evaluate the potential utility of a self-expandable intratracheal nitinol stent with flared ends for the treatment of tracheal collapse in dogs, endotracheal stenting therapy was performed under fluoroscopic guidance in four dogs with severe tracheal collapse. During the 4 to 7 month follow-up, after stent implantation, clinical signs, including dyspnea and respiratory distress, dramatically improved in all dogs. The radiographs showed that the implanted stents improved the tracheal collapse, and there were no side effects such as collapse, shortening or migration of the stents. In conclusion, the self-expandable intratracheal nitinol stents provided adequate stability to the trachea and were effective for attenuating the clinical signs associated with severe tracheal collapse.     

Use of ultrasonography in the diagnosis of tracheal collapse

Ultrasonographic Imaging of the cervical trachea was performed with the neck in both a neutral and a hyperextended position in 10 dogs with tracheal collapse. Tracheoscopy was used to confirm a diagnosis of tracheal collapse. The ultrasound investigation was repeated in 10 dogs of similar size but without tracheal abnormality. The ultrasonographic findings of the affected dogs were compared with those of the normal group and showed an alteration in the shape of the tracheal lumen in the ventrodorsal projection. This study highlights the possibility of identifying changes in the shape of the tracheal lumen during ultrasound investigations as an aid to the diagnosis of tracheal collapse.     

Peritracheal abscess associated with tracheal collapse and bilateral laryngeal paralysis in a dog

Tracheal collapse and bilateral laryngeal paralysis were diagnosed in an 8-month-old Cocker Spaniel that had acute onset of dyspnea and cyanosis. Surgical exploration of the mediastinum revealed an abscess involving the ventral wall of the trachea immediately caudal to the thoracic inlet. Both recurrent laryngeal nerves were entrapped in fibrous tissue surrounding the abscess. The dog recovered after tracheal resection and anastomosis and freeing of the entrapped nerves. The peritracheal abscess was suspected to have been the result of esophageal perforation secondary to foreign body penetration.     

Primary tracheal collapse in a cat

A 7-year-old, neutered male, domestic shorthair cat was presented for severe inspiratory dyspnea of 2 to 3 days' duration. Radiography and tracheobronchoscopy confirmed the diagnosis of primary extrathoracic tracheal collapse. The cat was treated with oxygen, dexamethasone, and terbutaline, but no improvement was seen. Surgical correction was performed using nine prosthetic tracheal ring implants. Clinical signs improved after surgery, and the cat continued to do well 11 months after surgery, despite development of unilateral laryngeal paralysis.     

Unilateral arytenoid lateralisation and extra-luminal polypropylene ring prostheses for correction of tracheal collapse in the dog

The surgical repair of tracheal collapse in 25 dogs is described. The initial presenting signs included coughing, dyspnoea, gagging, retching, exercise intolerance, cyanosis and collapse. Diagnosis was based upon the clinical signs, plain radiography and tracheal endoscopy. The collapse was corrected by the application of a number of extraluminal polypropylene prosthetic rings applied to the affected trachea. Additionally, a left arytenoid lateralisation was also performed. The perioperative complication rate was approximately 4 per cent, while the success rate was 75 per cent. The technique reduces the likelihood of catastrophic postoperative complications associated with iatrogenic laryngeal paralysis which is a possible complication of placement of extraluminal tracheal support devices.     

Incomplete tracheal intussusception in a dog

An 18-year-old male miniature poodle had a chronic nonproductive cough. On radiographic examination, an opacification resembling a foreign body was noticed within the trachea at the level of the sixth cervical vertebra. When the trachea was examined endoscopically, a circumferential flap-like lesion was found. To differentiate the invagination from an annular mass, thoracic computed tomography (CT) of the trachea was performed. There was cranial displacement and invagination of a tracheal segment creating the flap-like lesion. Tracheal intussusception should be considered as a cause of an annular tracheal mass.     

Atypical lateral tracheal collapse in a Yorkshire terrier

A 10-month-old, neutered female Yorkshire terrier was presented with a 6-month history of inspiratory dyspnoea, coughing and exercise intolerance. Tracheoscopy revealed marked lateral-to-lateral fixed collapse of the cervical trachea and mild collapse of the thoracic trachea. Surgical exploration revealed a marked reduction in lateral tracheal width and multiple malformed tracheal rings. Placement of extraluminal ring prostheses around the cervical trachea resulted in widening of the tracheal diameter and an immediate improvement in clinical signs. 6 years postoperatively the patient was reported to have an excellent quality of life with complete resolution of clinical signs.