A bladder assembly is provided in order to maintain the pressure in the balloon portion of a gastric band in a range corresponding to a so-called Green Zone. Multiple bladders are connected by flexible tubing which is connected at a distal end to the balloon portion of a gastric band. The elastically expandable bladders provide fluid pressure on the balloon portion of the gastric band in order to maintain the intra-luminal pressure within a desired range over a prescribed fill volume.
