Fixation system for an implantable medical device

Abstract

A medical implant, such as an implantable component ( 22 ) of a tissue-stimulating prosthesis. One example of such a prosthesis being a cochlear implant. The component ( 22 ) is adapted to be implanted at or adjacent a tissue surface within the recipient, such as a bone surface. The component ( 22 ) has a housing and at least one flange ( 42 ) extending outwardly therefrom. The flange ( 42 ) can be secured to the tissue surface via a tissue fixation device, such as a bone screw ( 43 ).

What is claimed is: 
     
         1 . A medical implant configured to be attached to a skull bone of a recipient, the implant comprising:
 a hermetically sealed housing encasing an electrical apparatus utilized to evoke a hearing percept in the recipient, wherein at least two flanges extend away from the housing, the at least two flanges located at substantially opposite sides of the housing; and   a magnet located outside the housing.   
     
     
         2 . The medical implant of  claim 1 , wherein the at least two flanges have respective top surfaces that extend in at least substantially in a plane that is parallel to a plane in which a top surface of the housing extends. 
     
     
         3 . The medical implant of  claim 1 , wherein
 with respect to a frame of reference looking downward on the implant normal to a longitudinal axis of the implant, an outboard most extension of the flanges extends further from the longitudinal axis than the outboard most extension of the magnet.   
     
     
         4 . The medical implant of  claim 1 , wherein said at least two flanges are formed separately from at least a portion of the housing and mounted to the housing. 
     
     
         5 . The medical implant of  claim 1 , wherein said at least two flanges are removably mounted to the housing. 
     
     
         6 . The medical implant of  claim 5 , wherein said at least two flanges or the housing is provided with engagement means that are engageable with the housing or flanges, respectively. 
     
     
         7 . The medical implant of  claim 1 , further comprising:
 a receiver coil disposed in a portion of the medical implant outside the housing, the coil extending about the magnet, wherein   with respect to a frame of reference looking downward on the implant normal to a longitudinal axis of the implant, an outboard most extension of the flanges extends further from the longitudinal axis than the outboard most extension of the coil.   
     
     
         8 . The medical implant of  claim 1 , further comprising:
 a receiver coil disposed in a portion of the medical implant outside the housing, the coil extending about the magnet, wherein   the at least two flanges have, respectively, one or more orifices passing therethrough that are adapted to receive a tissue fixation device; and   with respect to a frame of reference looking downward on the implant normal to a longitudinal axis, the orifices are further from the longitudinal axis than the furthest extent of the magnet from the longitudinal axis.   
     
     
         9 . The medical implant of  claim 1 , wherein:
 with respect to a frame of reference looking downward on the implant normal to a longitudinal axis, the flanges are located at least about a center of the housing relative to position along the longitudinal axis.   
     
     
         10 . The medical implant of  claim 1 , further comprising:
 a receiver coil disposed in a portion of the medical implant outside the housing, the coil extending about the magnet, wherein   the receiver coil and the housing collectively make up a receiver coil—housing assembly, and   with respect to a frame of reference looking downward on the implant normal to a longitudinal axis, the flanges are located away from a center of the receiver coil—housing assembly.   
     
     
         11 . The medical implant of  claim 1 , wherein said at least two flanges are formed separately from least a portion of the housing and mounted to the at least a portion of the housing. 
     
     
         12 . A medical implant configured to be implanted in a recipient, the medical implant comprising:
 a hermetically sealed housing including at least two flanges attached to and extending outwardly from substantially opposite sides of the housing, wherein the housing encases an electrical apparatus utilized to evoke a hearing percept in the recipient, and wherein respective flanges of the at least two flanges are securable to bone via respective apertures in the respective flanges of the at least two flanges;   a receiver coil disposed in a portion of the medical implant outside the housing; and a magnet, wherein the receiver coil extends about the magnet.   
     
     
         13 . The medical implant of  claim 12 , wherein at least one of said at least two flanges has a top surface that extends in at least substantially the same plane as that of a top surface of the housing. 
     
     
         14 . The medical implant of  claim 12 , wherein when a lower surface of the housing is positioned within a well formed in an outer surface of a skull bone and when the at least two flanges are secured to the bone, at least a portion of the housing is disposed outside the well. 
     
     
         15 . The medical implant of  claim 12 , wherein:
 the receiver coil is configured to receive radio waves generated by a component located outside the recipient, the radio waves containing audio information;   the medical implant is configured to provide a signal to the electrical apparatus in response to the received radio waves; and   the electrical apparatus is configured to respond to the signal to evoke a hearing percept based on the signal.   
     
     
         16 . The medical implant of  claim 12 , wherein said at least two flanges are part of an apparatus that is a separate part from a part that that makes up at least a portion of the housing. 
     
     
         17 . The housing of  claim 12 , wherein:
 the housing has a height that extends in a direction normal to a direction of extension of at least one flange of the at least two flanges away from the housing, wherein the housing is configured such that a bottom of the housing is located on an opposite side from a top of the housing, the height being the distance between the bottom and the top; and   all flanges of the at least two flanges are entirely located substantially at a top of the housing.   
     
     
         18 . A medical implant configured to be implanted in a recipient, the implant comprising:
 a hermetically sealed housing encasing an electrical apparatus utilized to evoke a hearing percept in the recipient, wherein   the medical implant includes two flanges extending outwardly from substantially opposite first and second sides of the housing,   there are only two flanges extending from the housing,   the medical implant is configured such that the bottom surfaces of the two flanges are substantially flush against the surface of the bone when a cavity is provided for the housing in the bone and are securable to the bone via an aperture in each flange,   the two flanges are at a topmost portion of the housing, and   the medical implant includes a receiver coil that is positioned, with respect to the housing, at a location relative to a third side of the housing different from the first and second sides, a magnet being encircled by the receiver coil.   
     
     
         19 . The medical implant of  claim 18 , wherein the receiver coil is encased in a silicone body extending to a location, relative to a lateral axis of the medical implant, above the housing and above the topmost portion of the two flanges. 
     
     
         20 . The medical implant of  claim 18 , wherein the receiver coil is part of an assembly that includes the magnet and silicone, wherein silicone of the assembly extends to and over a top of the housing. 
     
     
         21 . The medical implant of  claim 18 , wherein the receiver coil is part of an assembly that includes the magnet and silicone, wherein silicone of the assembly extends to and over only a portion of a top of the housing.