Hermetically sealed feedthrough connector using shape memory alloy for implantable medical device

• US 6,498,952 B2
• Filed: 03/08/2001
• Issued: 12/24/2002
• Est. Priority Date: 03/08/2001
• Status: Expired due to Fees

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories)
• Inventors: Imani, Ray, Nason, Clyde K.
• Primary Examiner(s): Schaetzle, Kennedy
• Assistant Examiner(s): DROESCH, KRISTEN L
• Application Number:
  US09/802,231
• Publication Number:
  US 20020128692A1
• Time in Patent Office: 656 Days
• Field of Search: 607/1, 607/4-5, 607/9, 607/36-38, 607/115-116, 607/119, 439/909
• US Class Current: 607/37
• CPC Class Codes: A61N 1/3752 Details of casing-lead connections

Abstract

A feedthrough connector for an implantable medical device includes a hermetically sealed housing containing an electrical circuit and a tubular barrel with an open end and a closed end defining a tubular channel that protrudes into the sealed housing while maintaining the seal of the housing. The inside of the tubular channel is open to the outside of the sealed housing through the open end and the tubular barrel also has a plurality of circumferentially spaced openings extending between an outer peripheral surface and the tubular channel. An electrical contact assembly electrically in common with the electrical circuit within the housing serves to make electrical contact with an electrical lead axially inserted into the open end of the tubular channel. The electrical contact assembly includes a plurality of contact members received in and projecting radially through a plurality of circumferentially spaced openings and a sleeve member of shape memory alloy freely overlies the contact members when in a first deformed-shape configuration but engage the contact members and the outer peripheral surface of the tubular barrel when in a second memory-shaped configuration, urging the contact members into mechanical, electrical, and hermetically sealed engagement with the electrical lead. The tubular channel may include a plurality of conductive cylindrical portions coaxial with the axis of the tubular barrel, the dimensions of the diameter of the successive cylindrical portions progressively decreasing from the open end to the closed end.

Claims

1. A feedthrough connector for an implantable medical device including a hermetically sealed housing and an electrical circuit within the housing, the feedthrough connector comprising:

a tubular barrel having an open end, a closed end, an outer peripheral surface, a longitudinally extending tubular barrel axis passing through the open end and the closed end, the tubular barrel defining a tubular channel that is adapted to protrude into the sealed housing while maintaining the seal of the housing, the inside of the tubular channel being open to the outside of the sealed housing through the open end, the tubular barrel also having a plurality of circumferentially spaced openings extending between the outer peripheral surface and the tubular channel; and

an electrical contact assembly on the tubular barrel that is adapted to be electrically in common with the electrical circuit within the housing for making electrical contact with an electrical lead axially inserted into the open end of the tubular channel, the electrical contact assembly including a plurality of contact members received in and projecting radially through the plurality of circumferentially spaced openings and a sleeve member of shape memory alloy freely overlying the contact members when in a first deformed-shape configuration and in engagement with the contact;

members and with the outer peripheral surface of the tubular barrel when in a second memory-shaped configuration and adapted to urge the contact members into mechanical, electrical, and hermetically sealed engagement with the electrical lead.

2. A feedthrough connector for an implantable medical device as set forth in claim 1:

wherein the tubular channel includes a plurality of conductive cylindrical portions coaxial with the axis of the tubular barrel, the dimensions of the diameter of the successive cylindrical portions progressively decreasing from the open end to the closed end, the tubular barrel also having a plurality of circumferentially spaced openings at each of the cylindrical portions extending between the outer peripheral surface and the tubular channel; and

including;

a plurality of electrical contact assemblies for making electrical contact between selected cylindrical portions of the tubular channel and associated cylindrical portions of the electrical lead axially inserted into the open end of the tubular channel, each electrical contact assembly including a plurality of sets of contact members received in and projecting through circumferentially spaced openings in the tubular barrel and a sleeve member of shape memory alloy freely overlying the contact members when in a first deformed-shape configuration and in engagement with the contact members and with the outer peripheral surface of the tubular barrel when in a second memory-shaped configuration and urging the contact members into mechanical, electrical, and hermetically sealed engagement with the electrical lead.

3. A feedthrough connector for an implantable medical device as set forth in claim 1:

wherein the electrical contact assembly includes an annular spring member which overlies the plurality of circumferentially spaced openings in the tubular barrel and has a plurality of cicumferentially spaced holes generally aligned with the openings in the tubular barrel; and

wherein the contact members are balls, each having a diameter greater than the diameter of the openings in the tubular barrel and greater than the diameter of the holes in the annular spring member, the balls being captured between the annular spring member and the tubular barrel and projecting through the holes for engagement with the electrical lead.

4. A feedthrough connector for an implantable medical device as set forth in claim 3:

wherein the annular spring member is discontinuous, having opposed finite ends capable of being separated against hoop bias from a closed position at which the finite ends are in a proximate relationship to an open position at which the finite ends are in a distant relationship for placement on the tubular barrel, then returned to the closed position when overlying the plurality of circumferentially spaced openings.

5. A feedthrough connector for an implantable medical device as set forth in claim 1:

wherein the tubular barrel has a pair of annular grooves in the outer peripheral surface longitudinally straddling the plurality of circumferentially spaced openings and lying in parallel spaced apart planes transverse of the tubular barrel axis; and

wherein the sleeve member has an inner peripheral surface with a pair of annular rims lying in parallel spaced apart planes aligned, respectively, with the annular grooves of the tubular barrel;

such that as the sleeve assumes the second memory-shaped configuration, the annular rims of the sleeve member fittingly engage with the annular grooves of the tubular barrel and hermetically seal the region therebetween when the electrical lead is axially inserted into the open end of the tubular channel and sealingly engaged therewith.

6. A feedthrough connector for an implantable medical device as set forth in claim 2:

wherein the tubular channel has an annular seal groove located intermediate successive cylindrical portions; and

including an intermediate seal member received in the annular seal groove and engageable with the electrical lead when axially inserted into the open end of the-tubular channel to isolate the circumferentially spaced openings associated with one cylindrical portion from the circumferentially spaced openings associated with the adjoining cylindrical portion.

7. A feedthrough connector for an implantable medical device as set forth in claim 1:

wherein the tubular barrel is of dielectric material; and

wherein the tubular barrel includes an annular flange fixed to the open end thereof welded to the housing of the implantable medical device to thereby hermetically seal the interior of the implantable medical device.

8. A feedthrough connector for an implantable medical device as set forth in claim 7:

wherein the tubular barrel is of ceramic material.

9. A feedthrough connector for an implantable medical device as set forth in claim 1:

wherein the tubular barrel includes an integral first circular band spaced from its open end; and

including;

a tubular extension member axially aligned with the tubular barrel and extending between first and second ends, the first end being proximate the tubular barrel, the tubular extension member having an annular flange at the second end, being an open end, distant from the tubular barrel, the flange at the second end being welded to the housing of the implantable medical device, the tubular extension member including an integral second circular band spaced from the first end; and

a connection sleeve of shape memory alloy freely overlying the tubular barrel and the tubular extension member between the first and second circular bands when in a first deformed-shape configuration and in engagement with the tubular barrel and the tubular extension member when in a second memory-shaped configuration to thereby firmly join the tubular barrel to the implantable medical device.

10. A feedthrough connector for an implantable medical device as set forth in claim 9:

wherein the tubular barrel is of dielectric material; and

wherein the tubular extension member is metallic.

11. A feedthrough connector for an implantable medical device as set forth in claim 1:

wherein the sleeve member assumes the first deformed shape configuration above a predetermined temperature and assumes the second memory-shaped configuration below the predetermined temperature.

12. A feedthrough connector for an implantable medical device as set forth in claim 1 including:

an electrical conductor electrically joining the sleeve member and the electrical circuit when the sleeve member is in the second memory-shaped configuration.