Abstract: Accurate Prediction of Submental Lymph Nodes Using Magnetic Resonance Imaging and Correlated Clinical Outcome for Lymphedema Surgery

Abstract

INTRODUCTION: Submental lymph node transfer has proved to be an effective approach for the treatment of lymphedema. This study was to investigate the anatomy and distribution of vascularized submental lymph nodes (VSLN) flap using Magnetic Resonance Imaging (MRI) and their clinical outcome. METHODS: Fifteen patients who underwent 19 VSLN flap transfers for upper or lower limb lymphedema were retrospectively analyzed. The number of submental lymph nodes was compared between pre-operative MRI, pre-operative sonography, intra-operative finding, post-operative sonography and post-operative CTA. The outcome was compared between preoperatively and postoperatively. RESULTS: All 19 VSLN flaps survived. 215 lymph nodes were identified in 30 submandibular regions by MRI. The mean number of submental lymph nodes on pre-operative MRI was 7.2 ± 2.4, on pre-operative sonography was 3.2 ± 1.1, on intra-operative finding was 3.1 ± 0.6, post-operative sonography was 4.6 ± 1.8, and post-operative CTA was 5.2 ± 1.9. 61% of the lymph nodes were located in the central two quarters of the line drawn from the mental protuberance to the mandibular angle. The actual harvest rate of submental lymph nodes was 72.2%. At a 12-months follow-up, mean episodes of cellulitis were improved from 2.7 ± 0.6 to 0.8 ± 0.2 (p < 0.01); mean of circumferential difference was improved 3.2 ± 0.4 cm (p < 0.03). The overall Lymphedema Quality-of-Life was improved 4.9 ± 0.3. (p < 0.04) CONCLUSION: The pre-operative MRI is a useful tool for the detection of mean 7.2 submental lymph nodes. Mean 72.2 % of submental lymph nodes can be successfully transferred for extremity lymphedema with optimal functional recovery.