Mechanical feedthroughs for implantable medical device

Abstract

An implantable medical device assembly comprises a sealed housing; a motor including a rotating output shaft within the sealed housing; a first coaxial shaft within the sealed housing, the first coaxial shaft being mechanically coupled to the rotating output shaft such that rotation of the rotating output shaft drives rotation of the first coaxial shaft; a second coaxial shaft external to the sealed housing, the second coaxial shaft being in axial alignment with the first coaxial shaft; an oscillating component mechanically coupling the first coaxial shaft to the second coaxial shaft, wherein rotation of the rotating first coaxial shaft drives the oscillation of the oscillating component, wherein the oscillation of the oscillating component drives rotation of the second coaxial shaft; and a flexible seal including the oscillating component. The sealed housing and the flexible seal combine to form a substantially sealed enclosure encasing the motor and the first coaxial shaft.

What is claimed is: 
     
         1 . An implantable medical device assembly comprising:
 a sealed housing;   a motor within the sealed housing, the motor including a rotating output shaft;   a first coaxial shaft within the sealed housing, the first coaxial shaft being mechanically coupled to the rotating output shaft such that rotation of the rotating output shaft drives rotation of the first coaxial shaft;   a second coaxial shaft external to the sealed housing, the second coaxial shaft being in axial alignment with the first coaxial shaft;   an oscillating component mechanically coupling the first coaxial shaft to the second coaxial shaft, wherein rotation of the rotating first coaxial shaft drives the oscillation of the oscillating component, wherein the oscillation of the oscillating component drives rotation of the second coaxial shaft; and   a flexible seal including the oscillating component,   wherein the sealed housing and the flexible seal combine to form a substantially sealed enclosure encasing the motor and the first coaxial shaft.   
     
     
         2 . The implantable medical device assembly of  claim 1 , further comprising an offset pin mechanically coupling the first coaxial shaft to the second coaxial shaft, wherein rotation of the rotating first coaxial shaft drives a circular motion of the offset pin about the axis of the first coaxial shaft, wherein the circular motion of the offset pin drives rotation of the second coaxial shaft;
 wherein the oscillating component is an oscillating cap, the oscillating cap being mechanically coupled to the offset pin such that the oscillating cap oscillates in unison with the circular motion of the offset pin,   
     
     
         3 . The implantable medical device assembly of  claim 2 , further comprising:
 a first bearing between the first coaxial shaft and the oscillating cap; and   a second bearing between the first coaxial shaft and the offset pin,   wherein the first and second bearing combine to allow the oscillating cap to oscillate without rotating while the first coaxial shaft and the second coaxial shaft rotate.   
     
     
         4 . The implantable medical device assembly of  claim 1 ,
 wherein the oscillating component is a nutating shaft, wherein a proximal end of the nutating shaft is coupled to the rotating output shaft and within the sealed housing,   wherein the assembly further comprises a central bearing passing through the sealed housing and supporting a central portion of the nutating shaft and within the sealed housing,   wherein a proximal side of the flexible seal covers a distal side of the central bearing, wherein a distal side of the flexible seal is secured to a distal portion of the nutating shaft located distally relative to the central bearing,   wherein the substantially sealed enclosure formed by the sealed housing and the flexible seal encases the motor, the rotating output shaft, the proximal end of the nutating shaft and the central bearing.   
     
     
         5 . The assembly of  claim 4 , wherein the nutating shaft is configured to only nutate and not rotate substantially when motor operates to rotate the rotating output shaft. 
     
     
         6 . The assembly of  claim 1 , wherein the flexible seal includes a metal bellows. 
     
     
         7 . The assembly of  claim 6 , wherein the metal bellows includes an electroformed metal bellows. 
     
     
         8 . The assembly of  claim 6 , further comprising:
 a first weld joint sealing an interface of the metal bellows and the sealed housing; and   a second weld joint sealing an interface of the metal bellows and the oscillating component.   
     
     
         9 . The assembly of  claim 1 , wherein the sealed housing and the flexible seal combine to form a hermetically sealed enclosure encasing the motor and the first coaxial shaft. 
     
     
         10 . The assembly of  claim 1 , further comprising a mechanically adjustable medical lead, the mechanically adjustable medical lead including a rotatable member mechanically connected to a distal end of the second coaxial shaft,
 wherein operation of the motor to rotate the second coaxial shaft rotates the rotatable member of the mechanically adjustable medical lead to move a position of an electrode of the mechanically adjustable medical lead to adjust a spacing between a proximal end of the medical lead body and the electrode.   
     
     
         11 . The assembly of  claim 10 , further comprising a force sensor configured to measure a resistance to movement of the position of the electrode and deliver a force signal to a processor based on the resistance to movement of the position of the electrode. 
     
     
         12 . The assembly of  claim 1 , further comprising a mechanically adjustable medical lead, the mechanically adjustable medical lead including a rotatable member mechanically connected to a distal end of the second coaxial shaft,
 wherein operation of the motor to rotate the rotating output shaft rotates the rotatable member of the mechanically adjustable medical lead to move a radial orientation an electrode of the mechanically adjustable medical lead.   
     
     
         13 . The assembly of  claim 1 , further comprising a mechanically adjustable medical lead, the mechanically adjustable medical lead including:
 an elongated medical lead body;   a retractable electrode located within a distal portion of the medical lead body;   an insulated conductor extending within the medical lead body, the insulated conductor being in electrical contact with the electrode and extending to a proximal end of the medical lead body; and   a rotatable member positioned adjacent to the proximal end of the medical lead body, the rotatable member being mechanically connected to a distal end of the second coaxial shaft, wherein operation of the motor to rotate the rotating output shaft rotates the rotatable member of the mechanically adjustable medical lead to move a position of the retractable electrode to selectively deploy and retract the retractable electrode from the medical lead body.   
     
     
         14 . A method of adjusting a mechanically adjustable medical lead,
 wherein the mechanically adjustable medical lead includes an electrode and a rotatable member, the rotatable member being mechanically coupled to the electrode,   the method comprising operating a motor within a hermetically sealed enclosure to drive the rotatable member of the medical lead and move a position of the electrode to adjust a spacing between a proximal end of the medical lead and the electrode.   
     
     
         15 . The method of  claim 14 , wherein the electrode is positioned adjacent a distal end of the medical lead and rotation of the rotatable member varies an overall length of the medical lead. 
     
     
         16 . The method of  claim 15 , further comprising measuring a resistance to movement of the position of the electrode with a force sensor and operating the motor to drive the rotatable member of the medical lead and move the position of the electrode based on the measured resistance to movement of the position of the electrode. 
     
     
         17 . The method of  claim 14 , wherein the mechanically adjustable medical lead further includes:
 an elongated medical lead body, wherein the electrode is located at a distal portion of the medical lead body and the rotatable member positioned adjacent to the proximal end of the medical lead body; and   an insulated conductor extending within the medical lead body, the insulated conductor being in electrical contact with the electrode and extending to the proximal end of the medical lead body.   
     
     
         18 . The method of  claim 14 , wherein the motor and the medical lead are part of an assembly, wherein the assembly further comprises:
 a sealed housing;   a motor within the sealed housing, the motor including a rotating output shaft;   a first coaxial shaft within the sealed housing, the first coaxial shaft being mechanically coupled to the rotating output shaft such that rotation of the rotating output shaft drives rotation of the first coaxial shaft;   a second coaxial shaft external to the sealed housing, the second coaxial shaft being in axial alignment with the first coaxial shaft;   an offset pin mechanically coupling the first coaxial shaft to the second coaxial shaft, wherein rotation of the rotating first coaxial shaft drives a circular motion of the offset pin about the axis of the first coaxial shaft, wherein the circular motion of the offset pin drives rotation of the second coaxial shaft; and   a flexible seal including an oscillating cap, the oscillating cap being mechanically coupled to the offset pin such that the oscillating cap oscillates in unison with the circular motion of the offset pin,   wherein the sealed housing and the flexible seal combine to form the hermetically sealed enclosure encasing the motor and the first coaxial shaft.   
     
     
         19 . The method of  claim 14 , wherein the motor and the medical lead are part of an assembly, wherein the assembly further comprises:
 a sealed housing, wherein the motor is within the sealed housing, the motor including a rotating output shaft;   a nutating shaft, wherein a proximal end of the nutating shaft is coupled to the rotating output shaft and within the sealed housing;   a central bearing passing through the sealed housing and supporting a central portion of the nutating shaft and within the sealed housing; and   a flexible seal, a proximal side of the flexible seal covering a distal side of the central bearing, and a distal side of the flexible seal being secured to a distal portion of the nutating shaft located distally relative to the central bearing,   wherein the sealed housing and the flexible seal combine to form the hermetically sealed enclosure encasing the motor, the rotating output shaft, the proximal end of the nutating shaft and the central bearing.   
     
     
         20 . The method of  claim 19 , wherein flexible seal is substantially fixed to the sealed housing and the nutating shaft.