Endoscope-Assisted Thoracic Duct Ligation and Cisterna Chyli Ablation Using Double O-Ring Wound Retractors in a Dog with Presumed Idiopathic Chylothorax.

Chylothorax is a challenging condition in dogs, and although endoscopic thoracic duct ligation (TDL) combined with cisterna chyli ablation (CCA) is an established surgical treatment, adequate operative exposure and visualization remain technically demanding. This report describes the use of double O-ring wound retractors (OWRs) with endoscopic assistance to perform TDL and CCA in a dog with presumed idiopathic chylothorax. A 5-year-old castrated male French Bulldog presented with dyspnea caused by chylous pleural effusion. Computed tomographic lymphangiography identified abnormal thoracic duct branching with collateral lymphatic vessels and focal contrast leakage, supporting the diagnosis of presumed idiopathic chylothorax. Surgical treatment was performed through a right paracostal abdominal approach and a right circumcostal transdiaphragmatic approach using double OWR. Following methylene blue injection into a mesenteric lymph node, the thoracic duct and cisterna chyli were visualized endoscopically, and thoracic duct ligation, cisterna chyli ablation, and pleural port placement were performed under endoscopic visualization using conventional surgical instruments. The dog recovered uneventfully, with pleural effusion becoming radiographically undetectable by POD 34 and remaining absent on thoracic radiography at POD 48. No major postoperative complications were observed during follow-up. At POD 150, the owner reported no respiratory abnormalities or other clinical signs suggestive of recurrent chylothorax. This case demonstrates the technical feasibility of incorporating endoscopic assistance into a previously described double OWR-assisted approach for TDL and CCA in a dog with presumed idiopathic chylothorax. Because this technique was evaluated in a single dog without objective comparative assessment, the present report is intended to describe technical feasibility rather than demonstrate improved surgical or clinical outcomes.