150. Utilization of Preoperative Magnetic Resonance Lymphangiography Predicts Number of Lymphovenous Bypasses and Response to Surgery

PURPOSE: Lymphedema of the extremities is a debilitating condition that commonly occurs after oncologic surgery or radiation therapy. Improvements in microsurgical techniques over the past few decades have led to a resurgence in physiological procedures whereby obstructed lymphatic channels are surgically bypassed to improve lymphatic drainage. At our institution, magnetic resonance lymphangiography (MRL) is routinely performed preoperatively to identify dominant lymphatic channels suitable for lymphaticovenular anastomosis. Our hypothesis is that preoperative MRL correlates with operative findings in patients undergoing lymphedema surgery. METHODS: All consecutive patients who underwent lymphovenous bypass in an extremity between September 2016 and June 2019 were retrospectively reviewed. Age greater than 18 years and no prior history of lymphedema surgery were required for inclusion. Preoperative MRL was performed in every patient, except those patients with implantable medical devices containing ferromagnetic materials. Patient demographics and clinical variables including symptoms related to lymphedema were collected. The number of lymphovenous bypasses performed at the time of surgery was compared to findings determined by preoperative MRL. Categorical variables were compared using Fisher’s exact test. RESULTS: Twenty-three patients met the inclusion criteria for this study. Mean age at presentation was 57 years with an average postoperative follow up of six months. The sensitivity of preoperative MRL identifying dominant lymphatic channels suitable for lymphaticovenular anastomosis was 94%. Compared to patients with no dominant lymphatic channels demonstrated on preoperative MRL, 92% of patients with MRL findings of at least one dominant lymphatic channel had three or more lymphovenous bypasses performed (n=12; p=0.0007) with 77% reporting a subjective improvement in symptoms (n=10; p=0.0474). In contrast, five patients had preoperative MRL demonstrating no dominant lymphatic channels, and none of these patients had more than two lymphovenous bypasses performed with 80% (n=4) reporting no improvement in symptoms. Five patients did not receive preoperative MRL due to the presence of an implantable medical device, and among this cohort, lymphovenous bypass was not performed in one patient due to inadequate lymphatic channels discovered at the time of surgery. CONCLUSION: Preoperative MRL is highly sensitive in identifying dominant lymphatic channels suitable for lymphaticovenular anastomosis. In this small series, the presence of at least one dominant lymphatic channel on preoperative MRL was associated with three or more lymphovenous bypasses being performed, and 77% of patients reported improvement in their lymphedema symptoms. We recommend the routine use of MRL in the preoperative planning for patients undergoing lymphedema surgery.