Surgery STAT: Tracheal collapse: rings or stents?
Aug 01, 2008
EDITOR'S NOTE: SurgerySTAT is a collaborative column between the American College of Veterinary Surgeons (ACVS) and DVM Newsmagazine. In September, Shawn Mattson, DVM, DVSc, BSc will discuss "Treating Subchondral Bone Cysts in the Fetlock Joint." Dr. Mattson is an ACVS board-certified surgeon who practices at Moore and Company Veterinary Services, a full-service equine hospital in Calgary, Alberta, Canada. Dr. Mattson, previously at the Ontario Veterinary College in Guelph, Ontario, has published scientific articles in the American Journal of Veterinary Research and Veterinary Surgery related to research on orthopedic infections in horses.
Tracheal collapse, or tracheal chondromalacia, is a progressive, degenerative condition of the trachea that can ultimately result in severe respiratory compromise.
Different underlying causes are recognized that can occur alone or in conjunction with one another and include: (1) Hyaline cartilage rings that lose integrity and can no longer support the tracheal lumen or (2) weakening of the trachealis muscle that contributes to the loss of tracheal lumen during different phases of respiration.The resulting clinical syndrome typically manifests as a "goose honk" cough with varying degrees of dyspnea and is most commonly identified in toy breed dogs. Non-surgical management techniques can be useful to palliate clinical signs for years, but more aggressive treatment often is required for those animals that eventually fail these more conservative approaches.
I consider the location of the collapse to be one of the most important factors in deciding which technique to recommend. Routine radiography can be useful for the diagnosis of concurrent conditions and the presence of tracheal collapse, but more dynamic studies obtained during coughing are needed to fully identify the extent of the collapse.
During inspiration, the subatmos-pheric airway pressures generated in the cervical trachea lead to collapse in that location, whereas during exhalation the increased intrathoracic pressures lead to collapse of the intra-thoracic trachea. This often can be appreciated upon careful evaluation of the respiratory pattern during physical examination as well.