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.