Dumon silicone stents can improve respiratory function in dogs with grade IV tracheal collapse: 12 cases (2019-2023).

OBJECTIVE: To evaluate the efficacy, complications, and outcome of Dumon silicone stent placement for dogs with grade IV tracheal collapse. ANIMALS: 12 client-owned dogs. CLINICAL PRESENTATION: Each dog was diagnosed with grade IV TC unresponsive to medical therapy and had severe obstructive respiratory failure. RESULTS: 12 dogs were included in the study. By the end of the study, 5 of 12 (41.7%) remained alive, while 7 of 12 (58.3%) dogs died. Survival times after stent placement ranged from 97 to 1,310 days (mean, 822.43 days; median, 810 days). Three of the 12 (25%) dogs died spontaneously, while 4 of 12 (33.3%) were euthanized. The cause of death was determined for 6 of 7 (85.7%) dogs and was TC related for 3 of 7 (50%). Causes of death related to TC were progressive airway collapse (2/3 [66.6%]) and incoercible cough (1/3 [33.4%]). Complications occurred in 9 of 12 (75%) cases and included granulation tissue growth (3/12 [25%]), incoercible cough (2/12 [16.7%]), stent migration (1/12 [8.3%]), and stent deformation (1/12 [8.3%]). Reduction of obstructive dyspnea and episodes of asphyxiation was achieved after Dumon silicone stent placement. CLINICAL RELEVANCE: The placement of an intraluminal Dumon silicone stent was a successful salvage treatment for TC in dogs that did not respond to medical management. Disease progression is inevitable, but substantial improvement of respiratory function may be achieved for months to years.

Tracheal stenosis in a yellow-crowned parrot (Amazona ochrocephala) due to diffuse ossification and osteopetrosis of tracheal rings.

Tracheal luminal stenosis can cause clinical respiratory distress in wild birds. We describe a case of tracheal stenosis due to diffuse ossification with osteopetrosis of tracheal rings in a yellow-crowned parrot (Amazona ochrocephala) with a history of chronic respiratory distress and death after development of marked dyspnoea. An ante-mortem radiographic examination revealed that the tracheal rings were radiopaque and that there were multiple areas of osteopenic change in long bones. At necropsy, there was stenosis of the tracheal rings characterized by complete replacement of cartilage by thickened compact bone with osteopetrosis and bone necrosis. The clinical respiratory distress and death of the parrot were associated with tracheal luminal stenosis due to thickening of the tracheal rings by diffuse ossification with osteopetrosis.

Tracheal stenosis following endotracheal intubation in a dog.

A 2-month-old intact female Rottweiler was presented for investigation of coughing and respiratory distress 9 d after an exploratory laparotomy for intestinal foreign body removal. Tracheal stenosis was suspected by radiography and confirmed with computed tomography (CT) and tracheoscopy. After 1 wk of medical management, clinical signs had resolved and the severity of the tracheal narrowing was markedly improved, as confirmed by radiography and tracheoscopy. Tracheal stenosis is a considerable complication of endotracheal intubation in veterinary medicine and may be medically managed, depending on the severity of the tracheal injury. Key clinical message: To our knowledge, this is the first clinical case report of tracheal stenosis resulting from endotracheal intubation in a dog and its resolution after medical management.

Sténose trachéale après intubation endotrachéale chez un chien. Une femelle Rottweiler intacte âgée de deux mois a été présentée pour examen de la toux et de la détresse respiratoire neuf jours après une laparotomie exploratrice pour le retrait d'un corps étranger intestinal. Une sténose trachéale a été suspectée par radiographie et confirmée par tomodensitométrie et trachéoscopie. Après une semaine de prise en charge médicale, les signes cliniques avaient disparu et la sévérité du rétrécissement trachéal s'était nettement améliorée, tel que confirmés par la radiographie et la trachéoscopie. La sténose trachéale est une complication majeure de l'intubation endotrachéale en médecine vétérinaire et peut être prise en charge médicalement, selon la gravité de la lésion trachéale.Message clinique clé:À notre connaissance, il s'agit du premier cas clinique de sténose trachéale résultant d'une intubation endotrachéale chez un chien et de sa résolution après prise en charge médicale.(Traduit par Dr Serge Messier).

Emergency tracheotomy and subsequent tracheal resection and anastomosis in a blue crane (Anthropoides paradiseus).

CASE DESCRIPTION: A 7-year-old female blue crane (Anthropoides paradiseus) was initially evaluated after it had suddenly developed signs of respiratory distress following aspiration of a rock. Emergency tracheotomy had been performed, and the rock had been removed from the proximal cervical portion of the trachea. Fifty-one days later, the clinical signs had returned and the crane was reevaluated. CLINICAL FINDINGS: On reevaluation, no obvious external abnormalities were appreciated at the previous surgical site and no discharge was observed from the glottis. Computed tomography and tracheoscopy revealed marked tracheal stenosis and architectural collapse of the trachea at the previous surgery site. TREATMENT AND OUTCOME: Tracheal resection and anastomosis was performed to remove the stenotic tracheal segment. Histologic examination of the resected tracheal segment revealed pyogranulomas with intralesional coccobacilli, fungal hyphae consistent with Aspergillus spp, possible parasitic ova, and features suggestive of mild to moderate heterophilic and lymphoplasmacytic tracheitis. The crane was treated with piroxicam, ceftiofur crystalline free acid, terbinafine, and itraconazole. At a follow-up examination 12 weeks later, no abnormalities were appreciated, and the surgical site had completely healed. CLINICAL RELEVANCE: To the authors' knowledge, this is the first reported case of successful tracheal resection and anastomosis in a bird of the order Gruiformes. The surgical approach used for the blue crane may be useful for removal of tracheal foreign bodies in this and other long-necked avian species.

A retrospective study of theophylline-based therapy with tracheal collapse in small-breed dogs: 47 cases (2013-2017).

Theophylline acts as a bronchodilator and has an anti-inflammatory effect. In addition, theophylline can be applied in patients where there are concerns regarding the side-effects of corticosteroids. This retrospective case series evaluated theophylline-based therapy in tracheal collapse (TC) canine patients. Forty-seven dogs with TC that received theophylline-based therapy during 2013-2017 were investigated. A fluoroscopic examination was performed to diagnose and grade TC. Theophylline was prescribed (7.5-30 mg/kg PO q12h) and the theophylline serum concentrations were measured. Coughing was assessed using a coughing scoring scale. The mean coughing score decreased after the theophylline-based therapy compared with that observed before treatment. Clinical improvements were observed in 46/47 patients (97.9%). As the intrathoracic TC grading increased, the final theophylline dosage also increased (p value 0.019). The symptom-free period (SFP) with therapy was 189.7 ± 194.45 days (range, 0-720 days) and there was no statistically significant correlation between the SFP and age, sex, or TC grade on fluoroscopy. Although theophylline has generally been used as a third-line treatment, it was used as the main treatment in this study and most patients showed improvements. Dogs have a wider therapeutic index of serum concentrations than humans, and any undesirable effects were easily overcome. With further research, this therapy may prove to be a useful approach, but its safety for long-term use in the treatment of canine TC patients needs to be established.

Long-term outcomes of 54 dogs with tracheal collapse treated with a continuous extraluminal tracheal prosthesis.

OBJECTIVE: To describe the surgical placement of a continuous extraluminal tracheal prosthesis (CETP) and report the subsequent postoperative clinical outcomes in dogs with tracheal collapse. STUDY DESIGN: Retrospective case series. ANIMALS: Fifty-four dogs. METHODS: Medical records of dogs in which cervical and/or thoracic inlet tracheal collapse was diagnosed and treated by placement of a CETP between 2010 and 2017 were reviewed to evaluate postoperative complications, changes in respiratory function, and survival. Histological examinations of tracheal tissues performed in 2 dogs at 51 and 57 months after surgery were also reviewed. RESULTS: Fifty-three (98%) dogs survived to discharge. Postoperative complications included laryngeal paralysis (1 dog), disseminated intravascular coagulation (1 dog), and recurrent tracheal collapse (2 dogs). None of the dogs exhibited clinical evidence of tracheal necrosis. Preoperative dry, harsh cough resolved in 87% of the dogs after surgery. Goose honking cough was resolved in 25 of 26 (96%) dogs. Median follow-up time was 30 months (range, 16 days to 76 months). The survival rate at 36 months was 86% (CI: 75%-96%). On histological examination in 2 dogs, the tracheal tissue surrounding the prosthesis was well preserved and without evidence of chronic inflammation. CONCLUSION: Continuous extraluminal tracheal prosthesis placement in dogs with tracheal collapse resulted in low postoperative complication rates and good long-term outcomes. CLINICAL SIGNIFICANCE: Continuous extraluminal tracheal prosthesis placement provides a viable alternative surgical option for managing dogs with tracheal collapse.

Interventional Radiology Management of Tracheal and Bronchial Collapse.

Chondromalacia of the tracheal and bronchial cartilages and redundancy of the dorsal tracheal membrane result in collapse of the large airways, leading to coughing and airway obstruction. It most commonly affects small-breed dogs, although larger-breed dogs, cats, and miniature horses are also sporadically reported. Dynamic airway imaging is used to confirm the diagnosis. The primary goal of medical management is to control clinical signs attributable to coughing and airway inflammation. When this is no longer effective, tracheal stents provide a minimally invasive, rapid way to restore airway patency. Bronchial stenting is in its infancy in veterinary medicine.

Effect of Variations in Stent Placement on Outcome of Endoluminal Stenting for Canine Tracheal Collapse.

The study's objective was to determine effects of relative size and placement location of endoluminal stents on incidence of complications and survival for canine tracheal collapse. Measurements were obtained on lateral radiographs before and after stenting to determine percent of the trachea occupied by the stent. These values were monitored over time and compared to complication rates and survival. Overall median survival time was 502 days. Six month survival rate was 78%, 1 yr survival was 60%, and 2 yr survival was 26%. Median percent of trachea occupied by the stent at initial placement was 79% (range, 41-93%). Percent of the trachea occupied by the stent at the time of placement did not significantly correlate to complication rate (0.397) or survival time (0.853). Incidence of serious complications was 37%, including granuloma formation, pneumonia, material failure, and stent migration. For patients experiencing serious complications, median survival was shorter, at 208 days, but was not significantly different from survival without serious complications. Within the margins of the data from this study, the proportion of the trachea occupied by the stent at the time of placement does not appear to impact incidence of complications or survival time in dogs with tracheal collapse.

[Effect of self-expanding bare metal stents of different diameters on the trachea of dogs].

Objective: To study the effect of self-expanding bare metal stents on the trachea of dogs, and therefore to provide useful information for choice of airway stents by interventional physicians. Methods: In this experiment, 8 beagles were randomly divided into 4 groups. Four self-expanding metal stents of different diameters (16, 18, 20 and 22 mm, respectively) were placed in the trachea of these beagles for 3 months and their impacts on normal trachea were observed. Results: In the 16 mm stent group (stent-to-airway diameter ratio 103%), good epithelialization was observed and the tracheal structure had no significant damage. In the 18 mm stent group (stent-to-airway diameter ratio 116%), slight granulation tissues were observed, but the cartilage and outer membrane were normal. In the 20 mm stent group (stent-to-airway diameter ratio 129%), severe granulation tissues were observed. Cartilage was damaged but outer membrane was normal. In the 22 mm stent group (stent-to-airway diameter ratio 142%), no obvious granulation tissues were found. Cartilage was normal, but outer membrane was ruptured. Conclusion: In a certain range, tracheal granulation tissues increased as the stent diameter increased. However, if the stent diameter continued to increase, a decreasing trend of tracheal granulation was observed, but severe tracheal injury by stent expansion force would occur.

Dislodgement of a right atrial thrombus and subsequent pulmonary thromboembolism following tracheal stent deployment in a dog.

OBJECTIVE: To report the management of a dog that required 2 treatments with mechanical ventilation; firstly for severe tracheal collapse and secondly following deployment of a nitinol tracheal stent that immediately preceded a nonoxygen responsive pulmonary thromboembolism (PTE), suspected to have originated from the right atrium. CASE SUMMARY: A 9-year-old female spayed Shetland Sheepdog was presented for management of a gallbladder mucocoele. Pertinent history included iatrogenic hyperadrenocorticism and tracheal collapse. The dog became clinical for tracheal collapse following laparoscopic cholecystectomy. Thoracic radiographs revealed moderate to severe tracheal collapse at the level of the thoracic inlet. Arterial blood gas was consistent with hypoventilation and mechanical ventilation was instituted. Given the severity of tracheal collapse, self-expanding nitinol tracheal stent placement was elected. Immediately following tracheal stent placement, the dog developed nonoxygen responsive hypoxemia requiring mechanical ventilation. Additional diagnostic tests revealed changes consistent with a PTE and a large thrombus in the right atrium. The dog was humanely euthanized. NEW OR UNIQUE INFORMATION PROVIDED: Dislodgement of a preexisting atrial thrombus has not been described as a complication following tracheal stent deployment. Additionally, although PTE is frequently considered to be oxygen responsive, it may not be if the embolism is severe enough.

Canine tracheal collapse.

Tracheal collapse occurs most commonly in middle-aged, small breed dogs. Clinical signs are usually proportional to the degree of collapse, ranging from mild airway irritation and paroxysmal coughing to respiratory distress and dyspnoea. Diagnosis is made by documenting dynamic airway collapse with radiographs, bronchoscopy or fluoroscopy. Most dogs respond well to medical management and treatment of any concurrent comorbidities. Surgical intervention may need to be considered in dogs that do not respond or have respiratory compromise. A variety of surgical techniques have been reported although extraluminal ring prostheses or intraluminal stenting are the most commonly used. Both techniques have numerous potential complications and require specialised training and experience but are associated with good short- and long-term outcomes.

Partial costectomy for tracheal collapse and stenosis associated with perinatal rib fracture in three Japanese Black calves.

2.3-month-old (Case 1), one-month-old (Case 2) and 6-month-old (Case 3), Japanese Black calves presented with mild to severe wheezing. All calves had histories of dystocia at birth with breech presentation. Physical examination, thoracic radiography, endoscopy or computed tomography indicated wheezing associated with tracheal collapse and stenosis caused by perinatal rib fractures. Partial resection of the fractured first and second ribs was performed on all calves. The respiration in Cases 1 and 2 immediately improved after the surgery, while Case 3 required two weeks to improve. Cases 1 and 3 grew up healthy and were sold at auction, but Case 2 had a recurrence of wheezing at three months post-discharge and showed growth retarding. Partial costectomy may be an effective solution for control of respiration, however, further cases are required to discuss the criteria for surgical management and to obtain favorable postoperative prognosis in calves with tracheal collapse and stenosis caused by perinatal rib fractures.

Traumatic tracheal diverticulum corrected with resection and anastomosis during one-lung ventilation and total intravenous anesthesia in a cat.

OBJECTIVE: This report describes the clinical findings and diagnostic images of a traumatic intrathoracic tracheal avulsion with a tracheal diverticulum in a cat. Furthermore, a complete description of the tracheal resection and anastomosis using one-lung ventilation (OLV) with total and partial intravenous anesthesia is made. CASE SUMMARY: A 3-year-old neutered male domestic shorthair cat weighing 6.8 kg was presented to the University Teaching Hospital for evaluation of increased respiratory noise 3 months following unknown trauma. Approximately 12 weeks prior to presentation, the cat had been seen by the primary care veterinarian for respiratory distress. At that time, the cat had undergone a tracheal ballooning procedure for a distal tracheal stricture diagnosed by tracheoscopy. The tracheal ballooning had provided only temporary relief. At presentation to our institution, the cat had increased respiratory effort with harsh upper airway noise auscultated during thoracic examination. The remainder of the physical examination was normal. Diagnostics included a tracheoscopy and a thoracic computed tomographic examination. The cat was diagnosed with tracheal avulsion, pseudotrachea with a tracheal diverticulum, and stenosis of the avulsed tracheal ends. Surgical correction of the tracheal stricture via a thoracotomy was performed using OLV with total and partial intravenous anesthesia. The cat recovered uneventfully and at last follow-up was active and doing well. UNIQUE INFORMATION PROVIDED: This case report describes OLV using standard anesthesia equipment that is available at most private practices. Furthermore, this case describes the computed tomographic images of the intrathoracic tracheal avulsion and offers a positive outcome for tracheal resection and anastomosis.

Tracheal Collapse in a Pekin Duck ( Anas platyrhynchos domestica).

A 5-year-old, 3.72-kg female Pekin duck ( Anas platyrhynchos domestica) was presented for acute respiratory distress, head shaking, and collapse. Similar spontaneously resolving episodes had previously occurred. Physical examination revealed severe inspiratory and expiratory dyspnea. Due to poor prognosis, euthanasia was elected. Postmortem examination revealed severe tracheal collapse involving the proximal trachea. The tracheal lumen was reduced in size by 75%. Histologic evaluation revealed ossification of the tracheal rings for approximately 60%-100% of their circumference. The bone trabecules presented characteristics of mature bone with a medullar cavity containing hematopoietic cells and adipocytes. There was also osseous metaplasia of the cartilage. In the lamina propria, there was lymphocytic infiltration and fibrosis, both moderate. To our knowledge, tracheal collapse has not been reported in a Pekin Duck.

Use of a Nitinol Wire Stent for Management of Severe Tracheal Stenosis in an Eclectus Parrot (Eclectus roratus).

A 25-year-old, female eclectus parrot (Eclectus roratus) presented for dyspnea 3 weeks after anesthesia and surgery for egg yolk coelomitis. Radiography, computed tomography, and tracheoscopy revealed multiple tracheal strictures spanning a length of 2.6 cm in the mid to distal trachea. Histopathologic examination revealed mild fibrosis, inflammation, and hyperplasia consistent with acquired tracheal strictures. Tracheal resection was not considered possible because of the length of the affected trachea. The strictures were resected endoscopically, and repeated balloon dilation under fluoroscopic guidance over the course of 10 months resulted in immediate but unsustained improvement. Computed tomography was used to measure the stenotic area. A 4 × 36-mm, custom-made, nitinol wire stent was inserted into the trachea under fluoroscopic guidance. After stent placement, intermittent episodes of mild to moderate dyspnea continued, and these responded to nebulization with a combination of saline, acetylcysteine, and dexamethasone. Multiple attempts to wean the patient off nebulization therapy and to switch to a corticosteroid-free combination were unsuccessful. The parrot eventually developed complications, was euthanatized, and necropsy was performed. Histologically, the tracheal mucosa had widespread erosion to ulceration, with accumulation of intraluminal exudate and bacteria, severe degeneration of skeletal muscle and tracheal rings, prominent fibrosis, and mild to moderate, submucosal inflammation. Clinicopathologic findings in this case suggested tracheomalacia, which has not been previously described in birds. Custom-made tracheal stents can be used for severe tracheal stenosis in birds when tracheal resection and anastomosis is not possible. Complications of tracheal stent placement in birds may include tracheitis and tracheomalacia. To our knowledge, this is the first report of tracheal stent placement in an avian species.

COMPARISON OF THE RADIOGRAPHIC AND TRACHEOSCOPIC APPEARANCE OF THE DORSAL TRACHEAL MEMBRANE IN LARGE AND SMALL BREED DOGS.

The etiology and clinical significance of increased radiographic opacity along the dorsal margin of the tracheal lumen has long been debated. Most often, this opacity is attributed to redundancy of the dorsal tracheal membrane (DTM), a condition that occurs with tracheal collapse. We hypothesized that the underlying etiology of this radiographic opacity differs between small breed dogs with tracheal collapse and small or large breed dogs without tracheal collapse. The purpose of this prospective, cross-sectional study was to compare the radiographic appearance of an increased opacity within the trachea to tracheoscopy findings in a group of small and large breed dogs. A total of 17 small breed dogs and 16 large breed dogs were included. Of these, only one did not have a radiographically visible DTM. Small breed dogs were divided into groups with tracheal collapse (n = 8) and those without (n = 9) based on tracheoscopy. Tracheal collapse was absent in larger breed dogs, however both large and small breed dogs demonstrated inward invagination of the DTM. In dogs with tracheal collapse, the DTM occupied a larger percentage of the tracheal luminal height on radiographs and a larger percentage of tracheal circumference on tracheoscopy vs. dogs with an invaginated DTM on tracheoscopy and dogs with no collapse and no invagination of the DTM. Findings supported the hypothesis that increased radiographic opacity along the dorsal margin of the trachea arises from different etiologies in dogs with and without tracheal collapse.

Tracheal resection and anastomosis after traumatic tracheal stenosis in a horse.

OBJECTIVES: To report a resection and anastomosis technique to treat trauma-induced tracheal stenosis. STUDY DESIGN: Case report. ANIMALS: A 9-year-old Warmblood gelding. METHODS: Endoscopy, radiography, and ultrasonography were used to diagnose a single ring tracheal stenosis; the stenotic region was resected and adjacent tracheal rings anastomosed with an end-to-end technique. RESULTS: The anastomosis healed completely despite formation of a unilateral partial mucosal stenosis "web," which was subsequently removed by transendoscopic laser surgery. During tracheal anastomosis, the left recurrent laryngeal nerve was damaged, causing laryngeal hemiplegia, later treated successfully by laryngoplasty. The horse returned to its previous level of work. CONCLUSIONS: This tracheal resection and anastomosis technique successfully provided the horse with a large tracheal lumen, and despite major complications, allowed a return to full athletic work.

Intra- and inter-observer reliability of combined segmental measurement techniques for predicting immediate post-deployment intraluminal tracheal stent length in dogs.

This study evaluated segmental measurement techniques for predicting immediate post-deployment intraluminal tracheal stent length in dogs with naturally occurring tracheal collapse. Radiographs of 12 client-owned dogs that underwent intraluminal tracheal stent placement were retrospectively reviewed. Tracheal lengths were divided into 1, 2, 3, or 4 equal segments. Stent lengths were predicted using the widest dorsoventral height of each segment, with and without the addition of 10%, and an accompanying foreshortening chart. Techniques were compared for intra- and inter-observer reliability, and post-deployment stent length predictability. There was good to high intra- and inter-observer reliability for all segmental measurements; median intra-class correlation coefficients were 0.98 and 0.92, respectively. Measuring 2 segments without the addition of 10% to the widths was significantly more accurate in predicting immediate post-deployment stent length in terms of percent (P = 0.03) and absolute difference (P = 0.02). Segmental measuring techniques are repeatable amongst observers and may help guide stent selection.

Fiabilité intra-observateur et inter-observateur des techniques de mesure de segments combinées pour la prédiction de la longueur d'une endoprothèse trachéale intraluminale immédiatement après le déploiement chez les chiens. Cette a étude a évalué les techniques de mesure de segments pour prédire la longueur des endoprothèses trachéales intraluminales immédiatement après le déploiement chez les chiens avec un collapse trachéal naturel. Des radiographies de 12 chiens, appartenant à des propriétaires, qui avaient subi le placement d'une endoprothèse trachéale intraluminale ont été examinées rétrospectivement. Les longueurs trachéales ont été divisées en 1, 2, 3, ou 4 segments égaux. Les longueurs d'endoprothèses ont été prédites en utilisant la hauteur dorsoventrale la plus large de chaque segment, avec et sans l'ajout de 10 % et le tableau d'effet de raccourcissement connexe. Les techniques ont été comparées pour la fiabilité intra-observateur et inter-observateur et la prédictibilité de la longueur de l'endoprothèse après le déploiement. Il y avait une fiabilité intra-observateur et inter-observateur de bonne à élevée pour toutes les mesures de segments; les coefficients moyens de corrélation entre les classes étaient de 0,98 et de 0,92, respectivement. La mesure de 2 segments sans l'ajout de 10 % aux largeurs était significativement plus exacte pour la prédiction de la longueur de l'endoprothèse immédiatement après le déploiement en termes de pourcentage (P = 0,03) et de différence absolue (P = 0,02). Les techniques de mesures de segments peuvent être répétées parmi les observateurs et peuvent aider à guider le choix de l'endoprothèse.(Traduit par Isabelle Vallières).

Long-term outcome of conventional endotracheal tube balloon dilation of tracheal stenosis in a dog.

This report describes a successful dilation of tracheal stenosis in a 16-year-old dog using a conventional endotracheal tube balloon. This technique should be considered as palliative treatment when owners decline other therapeutic options.

Résultat à long terme de la dilatation du ballonnet-tube trachéal d'une sténose trachéale chez un chien. Ce rapport décrit une dilatation réussie d'une sténose trachéale chez un chien âgé de 16 ans à l'aide d'un ballonnet-tube trachéal conventionnel. Cette technique devrait être considérée comme un traitement palliatif lorsque les propriétaires refusent les autres options thérapeutiques.(Traduit par Isabelle Vallières).