History. An 11 year-old, neutered male, Golden retriever presented for evaluation of regurgitation that developed 1 month ago. Chest radiographs demonstrated a 3 cm mass within the cranial mediastinum and a presumptive diagnosis of thymoma was made (fig 1 – radiograph).
The patient was placed in dorsal recumbency in the operating room. Right lung ventilation was maintained following placement of a bronchial blocker in the left mainstem bronchus. A Ternamian cannula was used to establish a left paracostal/transdiaphragmatic port and a 5 mm, 30 degree rigid scope was introduced into the chest. A 3 cm mediastinal mass was noted just caudal to the internal thoracic artery and cranial to the heart (fig 2 and video 1). Instrument ports were made at the 4th and 5th intercostal spaces. The mass was liberated from the mediastinal tissues with the use of 5 mm vessel sealing forceps (Ligasure). Once free, the mass was removed following enlargement of one of the ports (video 2).
Postop care. Epidural morphine was administered for 48 hours via an epidural catheter placed at the level of the thoracolumbar spine via the lumbosacral junction. The chest tube was removed 48 hours after surgery and the patient was discharged.
Outcome. A speedy recovery resulted following minimally invasive thymectomy. The regurgitation resolved within one week. Histopathology confirmed a diagnosis of noninvasive thymoma.