Video-assisted thoracoscopic resection of noninvasive thymomas using one-lung ventilation in two dogs

To report the technique and outcome of video-assisted thoracoscopic surgery (VATS) for resection of cranial mediastinal thymoma in 2 dogs.

Case report.

Eleven-year-old Labrador Retrievers (n=2).

Two dogs had VATS resection of thymoma. Preoperative computed tomography (CT) scans revealed well-circumscribed cranial mediastinal masses with dimensions of 4.5 cm x 4.2 cm x 3.7 cm and 2.1 cm x 2.1 cm x 4.1 cm (at the time of resection) without CT evidence of vascular invasion. One-lung ventilation (OLV) was achieved using a bronchoscopically placed double-lumen endobronchial tube. A 3-portal technique was used for VATS access to the thorax. Thymomas were dissected from the tissues of the cranial mediastinum with the aid of a harmonic scalpel and retrieved in specimen retrieval bags.

Two cranial mediastinal thymomas were resected successfully, with their capsules intact, using a VATS technique. One dog developed aspiration pneumonia postoperatively which resolved with treatment and remains healthy 18 months postoperatively with no radiographic evidence of tumor recurrence. The second dog was diagnosed with myasthenia gravis, megaesophagus, and aspiration pneumonia preoperatively and despite recovering well from the procedure had a second episode of aspiration pneumonia 5 days postoperatively and was euthanatized.

VATS resection of modestly sized noninvasive thymoma is possible in dogs. Careful case selection and preoperative imaging are the keys.

Thoracoscopic resection of modestly sized mediastinal masses forms part of an increasingly expansive set of indications for minimally invasive surgery in select veterinary patients.