34th Annual Scientific Meeting proceedings

Thoracoscopic ligation of a persistent right aortic arch (PRAA) in dogs is a minimally invasive surgical procedure aimed at correcting a congenital vascular anomaly that can lead to esophageal obstruction and subsequent clinical signs such as regurgitation, dysphagia, and weight loss. This presentation aims to provide a comprehensive overview of the surgical technique, indications, preoperative considerations, procedural steps, postoperative care, and potential complications associated with thoracoscopic PRAA ligation in dogs.

Indications
Persistent right aortic arch is a congenital anomaly in which a vascular ring around the esophagus leads to compression and subsequent esophageal dysfunction. There are many different types of vascular anomalies in dogs. Surgical intervention is indicated in dogs with clinical signs of esophageal obstruction, including regurgitation, dysphagia, poor weight gain, and weight loss, which are refractory to medical management. The most common breeds are German shepherds and Irish setters.

Preoperative Considerations
Prior to surgery, a comprehensive diagnostic workup is essential to confirm the diagnosis of PRAA and assess the extent of esophageal dilation and secondary complications. This typically includes thoracic radiography, +/- contrast esophagography, esophagoscopy, and thoracic computed tomography (CT). Preoperative stabilization, including placement of a gastrostomy tube, may be necessary in cases of dehydration, malnutrition, or aspiration pneumonia.

Surgical Technique
Thoracoscopic PRAA ligation is performed under general anesthesia with the dog placed in right lateral recumbency with the dorsum slightly elevated. Three ports are placed at the 8^th or 9^th ICS in the dorsal 1/3^rd to accommodate the thoracoscope and surgical instruments. A 4^th port can be placed at the costochondral junction of the 6^th or 7^th ICS for a retractor. The vascular ring is dissected with Laparoscopic right angle forceps and ligated using a vessel sealing device. The use of esophagoscopy or an orogastric tube to help ensure all the bands are transected is key to a successful surgery. A thoracostomy tube is usually placed to ensure no damage to lungs or vessels occurred during dissection.

Postoperative Care
Following surgery, dogs are closely monitored in a recovery area for signs of respiratory distress, hemorrhage, or pain. Intravenous fluids, antibiotics and pain medication are provided for the first postoperative night. Gradual reintroduction of a soft diet is initiated once esophageal motility improves, and long-term follow-up is recommended to assess for recurrence of clinical signs.

Complications
Although thoracoscopic PRAA ligation is associated with fewer complications compared to traditional open surgical techniques, potential risks include hemorrhage, pneumothorax, injury to adjacent structures, and recurrence of esophageal dysfunction. Close attention to surgical technique, patient monitoring, and postoperative care protocols can help minimize these risks and optimize outcomes.

Conclusion
Thoracoscopic persistent right aortic arch ligation is an effective and minimally invasive surgical option for correcting esophageal obstruction in dogs with PRAA. In one retrospective, 92% of dogs had no regurgitation after eating. In another retrospective, 92% survived surgery, but 18% had been euthanized within 2 months of surgery. Of those surviving, 71% of dogs had good to excellent long-term outcome. By providing precise visualization and manipulation of the vascular anomaly, this technique offers improved patient outcomes and faster recovery times compared to traditional open surgical approaches. However, careful patient selection, meticulous surgical technique, and comprehensive postoperative care are essential to ensure successful outcomes and minimize complications.