Sequential thoracoscopic thoracic duct occlusion and intra-abdominal lymphatic intervention for feline refractory idiopathic chylothorax.

Surgical management of feline idiopathic chylothorax remains unpredictable, with reported success rates varying widely despite combined procedures. We report a case of refractory idiopathic chylothorax in a cat that was successfully managed through a strategic, sequential surgical approach guided by indocyanine green (ICG) fluorescence. Initially, the cat underwent thoracoscopic thoracic duct occlusion (TDO) via clipping, but chylous effusion persisted. A 2nd surgery was conducted to achieve definitive thoracic duct ligation using sutures combined with additional clipping, yet the effusion remained refractory. Computed tomography after the 2nd surgery revealed a focal convergence of lymphatic vessels within the abdominal cavity. Based on this, a 3rd intervention was undertaken, combining thoracoscopic TDO with laparoscopic intra-abdominal lymphatic vessel occlusion and a cisterna chyli incision. Real-time ICG fluorescence imaging allowed precise identification and addressing of complex lymphatic collaterals. Chylothorax completely resolved ~1 mo after this 3rd surgery. The cat remained complication-free with no recurrence for 324 d after surgery. This case demonstrated the efficacy of a multimodal, sequential strategy for refractory feline chylothorax, integrating computed tomography-based diagnostic evaluation with combined thoracoscopic and laparoscopic lymphatic interventions. This comprehensive, minimally invasive approach, enhanced by real-time ICG visualization, offers a potent therapeutic option when conventional, single-cavity treatments fail. Key clinical message: This report describes for the first time a sequential and minimally invasive surgical approach to treat feline idiopathic chylothorax, by combining completely endoscopic (thoracoscopic and laparoscopic), ICG-guided TDO, intra-abdominal lymphatic vessel occlusion, and cisterna chyli incision. Moreover, this case showed that ICG can be effectively and noninvasively administered to the paw pads, obviating the need for invasive abdominal surgery.