Implanted valve, for draining cephalo-rachidien liquid from cerebral cavity for treatment of hydrocephaly, includes shutter, and pressure regulator with alloy drives and stepping gear wheel

摘要

The valve has a shutter (2), fitted to a drain pipe between a zone containing excess cephalo-rachidien liquid and a drain zone, and a pressure regulator for the shutter. The shutter regulator includes NITONOL alloy drives (6) which modify their mechanical properties and shape under the effect of temperature changes. The regulator has a stepping gear wheel (4) which modifies the shutter opening pressure in response to deformation of the drives. The drives includes a NITONOL spring which cooperates with the transmission wheel against the action of an elastomer cushion (19). The gear wheel cooperates with another spring (10) pressing against the shutter closing bearing (9) on a valve seat (7). The transmission has a ratchet wheel (11), fixed to a cam (12). which is rotated by the NITONOL drives. An actuating rod (21) has an end which cooperates with the cam (12) so as to compress the spring (10) between its other end and the shutter closing bearing. The valve also includes drive cooling and heating systems as well as an aerial for exciting these systems.