Upper Respiratory Fun

            My time this past week has been divided between the road and the clinic. Until now, most of my experience has been in a hospital setting, so I have been quite impressed by the variety of diagnostics and treatments that can be provided out of the back of a truck. This week alone, I have assisted with over half a dozen stall-side respiratory endoscopies. The hand-help scope, instead of being connected to a computer monitor, has an eyepiece that allows the vet to visualize the internal structures while still controlling the camera. We used the scope to diagnose dorsal displacement of the soft palate, rule out guttural pouch infection, visualize chondritis of the arytenoid cartilage (swollen larynx), and perform alveolar lavages to test for lower respiratory infections. Most of the time the horses require little to no sedation for this procedure.

            I spent one afternoon with Dr. Berthold as he treated three horses with dorsal displacement of the soft palate, also referred to as flipping the palate. Normally, the soft palate should sit snuggly underneath the epiglottis of the larynx. Inflammation, irritation, or malformation of the epiglottis can cause it to slip underneath the soft palate. Most horses can self-correct the displacement by swallowing. In those that don’t self-correct, the soft palate becomes an airway obstruction that can affect athletic performance. Dr. Berthold takes a two-step approach to correct chronic displacement. First, he uses a laser, directed by the endoscope, to cauterize the soft palate. Ideally the resulting inflammation and scar tissue will help keep the epiglottis above the soft palate. Next, we laid each horse down to perform a myectomy. This procedure entailed making a midline incision over the cricoid cartialges and first few tracheal rings, then removing the tendonous insertion and part of the body of the sternothyroideous muscle, and finally removing part of the body of the sternohyoideus muscle. The purpose of the myectomy is to inhibit the backward motion of the epiglottis that allows it to slip under the soft palate. Dr. Berthold has gotten very good results by combining the two strategies. A huge advantage of doing this procedure in the stall is efficiency; we had three procedures completed and the horses recovered in less than three hours. The drawback is that recovery can be a little more risky. Although the horses were anesthetized for significantly less time than if done in a surgery suit, they recovered in a wooden stall instead of a padded room. It is always interesting to see the pros and cons of different approaches and compare a farm call to a hospital environment.