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.     

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.     

Measurement of tracheal diameters using ultrasonography versus computed tomography in Beagle dogs

ObjectiveTo compare ultrasonography with computed tomography (CT) for assessment of tracheal diameter as a feasibility study for endotracheal tube selection.Study designProspective study.AnimalsA total of nine Beagle dogs with a median (interquartile range) weight of 7.4 (7.2–7.7) kg.MethodsTracheal diameter measurements were obtained at two locations: 1 cm proximal to caudal border of the cricoid cartilage (sublaryngeal; SL) and dorsal to above cranial border of the manubrium (thoracic inlet; TI). For CT, dogs were anesthetized with propofol and sevoflurane, in sternal recumbency, and measurements obtained after controlled ventilation–induced apnea and the endotracheal tube cuff was deflated. Transverse diameter, right and left 45° oblique diameters were measured. For ultrasonography, unsedated dogs were standing with slight neck extension, and images obtained in ventrodorsal, 45° right and left oblique ways after expiration. Diameters between the tracheal lumen mucosal borders were measured. The degree of agreement between the tracheal diameters measured at SL and TI locations with CT (TD_CT-SL and TD_CT-TI) and ultrasonography (TD_US-SL and TD_US-TI) was verified using the Bland-Altman method.ResultsThe agreement between the measurements obtained with CT and ultrasonography was revealed by Bland-Altman analyses, although ultrasonography tended to slightly underestimate the tracheal diameter.Conclusions and clinical relevanceUltrasonography can be applied for tracheal diameter measurement. Although further studies are required, an endotracheal tube selection method, using ultrasonography, could be proposed.     

Ultrasonographic evaluation of tracheal collapse in dogs

Tracheal ultrasonography was performed to measure the width of the tracheal ring shadow and to assess the clinical relevance of these measurements for identifying tracheal collapse. The first tracheal ring width (FTRW) and thoracic inlet tracheal ring width (TITRW) were measured on both expiration and inspiration. The mean of the FTRW width (129 dogs) was greater in expiration (10.97 ± 1.02 mm, p = 0.001) than that in inspiration (9.86 ± 1.03 mm). For 51 normal dogs, the mean of the TITRW width was greater in expiration (9.05 ± 1.52 mm, p = 0.001) than in inspiration (8.02 ± 1.43 mm). For 78 tracheal collapse dogs, the mean of the TITRW width was greater in expiration (15.89 ± 1.01 mm, p = 0.001) than in inspiration (14.85 ± 1.17 mm). The TITRW/FTRW ratio of the normal dogs was higher (p = 0.001) in expiration (0.81 ± 0.09) than that in inspiration (0.79 ± 0.10). When compared between the normal and tracheal collapse dogs, the TITRW/FTRW ratio was also increased (p = 0.001) both in expiration (1.54 ± 0.09) and inspiration (1.47 ± 0.08), respectively. Based on these results, the cutoff level of the TITRW/FTRW ratio was statistically analyzed according to the receiver operating characteristic curve and it could be set at 1.16 in expiration and at 1.13 in inspiration. We have demonstrated that tracheal ultrasonography is a useful technique for the evaluation of tracheal collapse and it can be a supportive tool together with the radiographic findings for making the correct diagnosis.     

Surgical outcomes in dogs with tracheal collapse treated with a novel cross-and-hook braided endoluminal stent

BackgroundStenting is an effective treatment option for tracheal collapse in dogs. Cross-braided tracheal stents are currently the norm in veterinary medicine, but cross-and-hook braided stents have recently been adopted in human medicine. We examined whether stents manufactured using this novel braiding technique provided additional advantages for the treatment of tracheal collapse in dogs.ObjectivesTo evaluate the outcomes of cross-and-hook braided stent implantation in the treatment of tracheal collapse in dogs.MethodsThe medical records of 22 client-owned dogs that underwent luminal placement of cross-and-hook braided Fauna Stents for the treatment of tracheal collapse between January 2018 and July 2021 were examined and data on canine signalment, clinical signs, diagnostic test results, surgical outcomes, and postoperative complications were retrieved and analyzed statistically.ResultsTwenty-six stents were surgically implanted, with 20 dogs (90.9%) receiving one stent and the remaining two (9.1%) receiving two or more stents. All dogs survived the procedure. The median survival time at a median follow-up of 990 days was 879 days. At the final follow-up examination, loss or mild improvement of cough was observed in all dogs.ConclusionsCompared with conventional lumen stents, the cross-and-hook braided Fauna Stent offered a higher survival rate and improved clinical symptoms in all patients. The results of this study suggest that the Fauna Stent may be a promising treatment option for dogs with tracheal collapse.     

Management of apposing,full‐thickness tracheal perforations in two horses

Two horses, one 15‐year‐old Arabian gelding and one 10‐year‐old Quarter Horse gelding, presented with a history of marked subcutaneous emphysema. The first case exhibited no external wound, although there was a depression noted on the ventral neck. The second case had a laceration on the ventral aspect of the neck over the trachea. Endoscopic examination revealed both horses to have concurrent dorsal and ventral perforations of the trachea. The horses were managed by placing a short, cuffed, J‐shaped tracheostomy tube in the ventral perforation, while the dorsal perforation healed. The dorsal perforation in the first horse was allowed to heal by second intention, whereas sutures were placed in the dorsal perforation in the second case to reduce the healing time. Both horses were maintained on oral antimicrobial and nonsteroidal anti‐inflammatory medications throughout treatment. The dorsal perforation healed after 13 days in the first horse, and 22 days in the second horse. The ventral perforation healed in both horses by second intention following tracheostomy removal, giving a cosmetically acceptable result. In addition to facilitating tracheal healing, the tracheostomy tubes prevented the progression of subcutaneous emphysema, and promoted its resolution.     

Assessment of computed tomography derived cricoid cartilage and tracheal dimensions to evaluate degree of cricoid narrowing in brachycephalic dogs

The aims of this observational, analytical, retrospective study were to (i) obtain computed tomographic (CT) cricoid dimensions (height, width, and transverse‐sectional area), (ii) compare the cricoid dimensions between brachycephalic and mesaticephalic breeds, and (iii) compare cricoid cartilage dimensions between dogs without and affected with brachycephalic airway syndrome. The study is important to help to further evaluate and understand the anatomical components of brachycephalic airway syndrome. Measurements were performed in 147 brachycephalic and 59 mesaticephalic dogs. The cricoid cartilage was found to be significantly more oval in Pugs and French Bulldogs compared to mesaticephalic breeds. The cricoid cartilage transverse‐sectional area was smallest for the Pug and, after adjusting for weight, significantly smaller for Pugs (P < 0.001), Boston Terriers (P = 0.001), and French Bulldogs (P < 0.001) compared to Jack Russell Terriers. The tracheal transverse‐sectional area at C4 of English Bulldogs was significantly smaller than for Jack Russell Terriers (P = 0.005) and Labradors (P < 0.001). The cricoid cartilage transverse‐sectional area:weight ratio was significantly lower in brachycephalic breeds compared to mesaticephalic breeds (P < 0.001). The cricoid cartilage:trachea at C4 transverse‐sectional area for brachycephalic dogs was significantly larger than for mesaticephalic dogs (<0.001), demonstrating that the trachea was the narrowest part of the airway. No significant differences were found for cricoid dimensions between dogs affected with and without brachycephalic airway syndrome. However, large individual variation was found among the brachycephalic breeds and further studies investigating the relationship between cricoid cartilage size, laryngeal collapse, concurrent tracheal hypoplasia, and/or severity of brachycephalic airway syndrome are warranted.     

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.     

Management of perianal fistulae in five dogs using azathioprine and metronidazole prior to surgery

OBJECTIVE: To evaluate combination therapy with azathioprine and metronidazole in German Shepherd Dogs with perianal fistulae. DESIGN: Prospective study. PROCEDURE: Five dogs (31.5 to 36.0 kg) with perianal fistulae were treated with azathioprine (50 mg per dog orally every 24 h) and metronidazole (400 mg per dog orally every 24 h). Patients were re-evaluated at 2 week intervals by inspection, palpation, photographs of the perineal region and assessment of white blood cell counts where possible. Treatment was continued until improvement in lesions reached a plateau. Surgical excision of residual fistulae and anal sac remnants was then performed, with medical therapy continued for an additional 3 to 6 weeks. RESULT: Signs attributable to anal irritation were reduced or eliminated in all dogs within 2 weeks, although visible healing of lesions progressed more slowly. Ulcerated lesions reduced in surface area and depth, and some fistulae healed completely. Non-healing areas were usually associated with anal sac rupture or chronic fibrosis. Visible improvement typically reached a plateau 4 to 6 weeks after commencing treatment. Immunosuppressive therapy continued for 5 to 24 weeks before surgical intervention to remove anal sacs (four dogs) and/or residual fistulae (five dogs). All dogs remain disease free 7 to 10 months postoperatively. No important complications of treatment were encountered. CONCLUSION: Azathioprine with metronidazole effectively reduced perianal irritation, and the severity and extent of lesions prior to surgery. Treatment was economical even in large dogs and associated with few untoward sequelae. The combined use of immunosuppressive and antimicrobial therapy followed by surgery minimised potential morbidity associated with aggressive use of either medical of surgical treatment alone.     

Detection of blood‐brain barrier dysfunction using advanced imaging methods to predict seizures in dogs with meningoencephalitis of unknown origin

BackgroundThe blood‐brain barrier (BBB), which separates the intravascular and neuropil compartments, characterizes the vascular bed of the brain and is essential for its proper function. Recent advances in imaging techniques have driven the development of methods for quantitative assessment of BBB permeability.Hypothesis/ObjectivesPermeability of the BBB can be assessed quantitatively in dogs with meningoencephalitis of unknown origin (MUO) and its status is associated with the occurrence of seizures.AnimalsForty dogs with MUO and 12 dogs without MUO.MethodsRetrospective, prospective cohort study. Both dynamic contrast enhancement (DCE) and subtraction enhancement analysis (SEA) methods were used to evaluate of BBB permeability in affected (DCE, n = 8; SEA, n = 32) and control dogs (DCE, n = 6; SEA, n = 6). Association between BBB dysfunction (BBBD) score and clinical characteristics was examined. In brain regions where BBBD was identified by DCE or SEA magnetic resonance imaging (MRI) analysis, immunofluorescent staining for albumin, glial fibrillary acidic protein, ionized calcium binding adaptor molecule, and phosphorylated mothers against decapentaplegic homolog 2 were performed to detect albumin extravasation, reactive astrocytes, activated microglia, and transforming growth factor beta signaling, respectively.ResultsDogs with BBBD had significantly higher seizure prevalence (72% vs 19%; P = .01) when compared to MUO dogs with no BBBD. The addition of SEA to routine MRI evaluation increased the identification rate of brain pathology in dogs with MUO from 50% to 72%.Conclusions and Clinical ImportanceImaging‐based assessment of BBB integrity has the potential to predict risk of seizures in dogs with MUO.