Prospective data on hiatal hernia in dogs and effect of brachycephalic obstructor syndrome surgery

Hiatal herniation is a relatively uncommon problem in dogs causing regurgitation of food and water, discomfort and the potential for the development of esophageal inflammation, esophageal stricture and aspiration pneumonia. In veterinary medicine there is a relatively rudimentary understanding of the function of the canine gastro-esophageal junction (GEJ), which forms the natural barrier for reflux of food, water and stomach acid back up into the esophagus. The lower esophageal sphincter (LES) is created by the muscular tone within the circular smooth muscle of the muscularis mucosa of the distal esophagus as well as the mechanical support provided by the attachments of the esophagus to the diaphragm as it passes from the chest into the abdominal cavity.

Surgical techniques for the treatment of hiatal herniation (HH) in people have been extensively studied and have received rigorous evaluation over the years in the scientific literature. The same cannot be said for HH in dogs. Of the group of gastroesophageal junction (GEJ) anomalies that are seen in the dog (which includes sliding hiatal hernia, paraesophageal hernia and gastroesophageal intussusception) sliding hiatal hernia is by far the most common. This condition can arise as a congenital anomaly and has been reported most commonly in this form in young Shar Peis. Acquired HH can be seen secondary to airway obstructive disease or neuromuscular disorders affecting the diaphragm. In brachycephalic breeds it is thought that increased inspiratory effort leads to a reduction in intra-esophageal and intrapleural pressures possibly leading to the distal esophagus and stomach being pulled into the thoracic cavity during inspiration. Clinical observations have been made to substantiate this proposed pathophysiology where a population of bulldogs with HH were shown to exhibit the more severe manifestations of brachycephalic syndrome compared to Bulldogs without HH.  [...]