LVA orientations such as lymphaticovenous end-to-end (LVEEA), end-to-side (LVESA), and side-to-end (LVSEA) are commonly performed. Each orientation has its own advantages and disadvantages. The key factors affecting the type of anastomotic orientation are the sizes of the LVs and the RVs, and the relative distance between them. Most published literatures have focused on LVSEA2-9, which is considered to be the most efficient. With one anastomosis in LVSEA, the RV is able to drain both the antegrade and retrograde lymphatic flow. Nevertheless, how to determine the anastomotic orientation has remained ambiguous. In this study, we aimed to establish the basis of selecting the proper anastomotic orientation, based on the size and comparative size discrepancy between LV and RV. To the best of our knowledge, this is the first report to focus on this subject.

Inclusion Criteria:

• lymphedematous lower limbs (International Society of Lymphology stage I-III) between March 2016 to October 2018 were included

Exclusion Criteria:

• Patients whose data were missing will be excluded.

This retrospective observational study was approved by the institutional review board in our hospital. From March 2016 to October 2018, 100 patients with 103 lymphedematous lower limbs (International Society of Lymphology stage I-III) were included. All the patients underwent supermicrosurgical LVA performed by a single surgeon using a high-power microscope.