D67. Functional Outcomes following Microsurgical Thoracic Duct Lymphovenous Bypass

PURPOSE: Thoracic duct (TD) lymphovenous bypass is a novel treatment for patients with symptomatic TD occlusion. Treatment response following surgery has yet to be fully characterized. METHODS: A retrospective review of all nonsyndromic patients undergoing TD bypass between 2019-2022 at our institution was performed. All cases were performed with intraoperative lymphangiography by interventional radiology. Postoperative functional outcome was assessed at one month and was compared to baseline presentation at the time of initial evaluation. RESULTS: TD bypass was attempted in 15 patients and completed in 14. Eight were female with a mean age of 44.8±13.9 yr. Eight patients (57.1%) had isolated TD occlusion at the level of the TD-central venous junction. Presenting pathologies included: chylous ascites (N=9), protein-losing enteropathy (N=6), lower-extremity lymphedema (N=5), and chylothorax/plastic bronchitis (N=5). Lymphovenous anastomosis was performed between the TD and the external jugular vein in ten patients with one undergoing vein grafting. Eight patients (57.1%) saw symptomatic improvement. Four patients saw improvement in lymphedema, three patients had reduced need for paracentesis in the setting of chylous ascites, and one patient had resolution of bronchial lymphatic casts. Six patients did not see any functional change in their condition. Five patients experienced complications (two infections of abdominal source, 2 TD leaks, 1 seroma). Seven of eight patients with positive treatment response had isolated distal TD occlusion without other lymphatic disease or malformation. CONCLUSION: TD lymphovenous bypass is a promising treatment for patients with isolated distal TD occlusion and was associated with improvements in lymphedema and chylous ascites.