An implant for treating obstructive sleep apnea includes a first chamber (26) containing an incompressible fluid (34), a second chamber (28a, b) containing a compressible fluid (36a, b), and a flexible diaphragm (30, 32) separating the first and second chambers. The incompressible fluid is in communication with the compressible fluid via the flexible diaphragm. The first chamber has a first volume that remains constant in response to an external force applied upon the implant and the second chamber has a second volume that is changeable when the external force is applied upon the implant. The flexible diaphragm is extendible into the second chamber for reducing the second volume of the second chamber and compressing the compressible fluid within the second chamber. The compressible fluid within the second chamber provides less resistance to flexing during initial flexing of the implant and more resistance to flexing during further flexing of the implant.
