Answer:
Lymphedema is treated using compression pumps and compression hosiery. The hosiery goes over the afflicted limb, and the pump pressurizes the hosiery. This compresses the limb, and causes the fluid that has built up in that region of the body to dissipate.
Here's a link with more info on the subject:
http://vitalitymedical.wordpress.com/2009/07/31/lymphedema-treatment/