Method for making a body implantable sensor

• US 5,490,323 A
• Filed: 01/30/1995
• Issued: 02/13/1996
• Est. Priority Date: 06/14/1991
• Status: Expired due to Fees

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories)
• Inventors: Thacker, James R., Moaddeb, Shahram, Weinberg, Alvin H.
• Primary Examiner(s): Arbes, Carl J.
• Application Number:
  US08/380,764
• Time in Patent Office: 379 Days
• Field of Search: 29/825, 128/634, 607/22, 607/122
• US Class Current: 29/825
• CPC Class Codes: A61N 1/056 Transvascular endocardial electrode systems
• CPC Class Codes: A61N 1/36557 controlled by chemical substances in blood
• CPC Class Codes: A61N 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371
• CPC Class Codes: Y10T 29/49117 Conductor or circuit manufacturing

Abstract

The present invention includes a body implantable lead having a multipolar proximal connector, at least a first conductor coupled to at least one stimulating electrode, a sensor for sensing at least one physiologic parameter of the body, and a second and a third conductor coupled to the sensor. The sensor is hermetically sealed in a D-shaped housing. Sensor components are mounted onto a microelectronic substrate which is advantageously placed on an inner flat portion of the D-shaped housing. End caps having sealing rings, either glass frit or metal, are used to seal the ends of the shell. A hermetic seal is easily achieved by heating the sealing material until they re-flow between the end caps and the shell. Advantageously, the sensor terminals are sized to fit snugly within a narrow bore of the end cap which is then circumferentially welded closed. The D-shaped sensor is placed on a carrier having at least two lumens. At least the first and second conductors pass through the lumens for connection with the stimulating electrode and the distal end of the sensor. Advantageously, the D-shaped housing reduces the area that needs to be hermetically sealed by more than half, and thus reduces the overall diameter of the lead. Advantageously, the conductors coupled to the sensor function independently from the stimulation conductors so that interference with basic operation of the pacemaker is prevented.

Claims

1. A method for making a body implantable optical sensor, the method comprising the steps of:

forming a D-shaped, optically clear, tubular shell;

mounting the sensor onto the flat inner surface of the D-shaped shell;

forming two end caps dimensioned to seal the open ends of the shell, each end cap being formed to pass a sensor terminal;

forming a sealing ring about one end of each of the end caps;

heating the two end caps until the sealing ring reflows to form a hermetic seal; and

heating the two end caps until the sensor terminals are hermetically sealed to the end caps.

2. The method, as recited in claim 1, wherein the step of forming the D-shaped shell comprises the step of molding liquid glass or glass ceramic into a D-shaped mold.

3. The method, as recited in claim 1, wherein the step of forming the D-shaped shell comprises the step of extruding liquid glass or glass ceramic into a D-shaped mold.

4. The method, as recited in claim 1, wherein the step of forming the D-shaped shell comprises the step of machining glass ceramic or optically clear ceramic into a D-shape.

5. The method, as recited in claim 1, wherein the step of forming a sealing ring comprises the step of forming a glass frit sealing ring about one end of each of the end caps.

6. The method, as recited in claim 1, wherein the step of forming a sealing ring comprises the step of forming a metal sealing ring about one end of each of the end caps.

7. The method, as recited in claim 1, wherein the step of mounting the sensor comprises the steps of:

mounting the sensor on a substrate;

attaching a conductive wire for each sensor terminal; and

slidably mounting the substrate within the D-shaped shell.

8. The method, as recited in claim 7, wherein the step of forming two end caps comprises the step of forming at least one end cap having a narrow channel dimensioned to slidably receive one of the conductive wires therethrough.

9. The method, as recited in claim 7, wherein the step of forming two end caps comprises the step of forming at least one inner cap having a channel dimensioned to slidably receive the sensor.

10. The method, as recited in claim 9, wherein the step of forming two end caps further comprises the steps of forming at least one outer cap dimensioned to mate with the inner cap and having a channel dimensioned to slidably receive one of the conductive wires therethrough.

11. The method, as recited in claim 10, further comprising the step of circumferentially welding the outer cap to the inner cap at the point where the outer cap mates with the inner cap.

12. The method, as recited in claim 10, wherein the step of heating the two end caps until the sensor terminals are hermetically sealed comprising the step of circumferentially welding the outer cap to the respective conductive wire.

13. A method for making a body implantable sensor, the method comprising the steps of:

forming a D-shaped, tubular shell with sealing rings at both ends;

mounting the sensor onto the flat inner surface of the D-shaped shell, the sensor having a conductive wire pre-attached to each of two sensor terminals;

attaching an end cap to each open end of the D-shaped shell, at least one end cap having an inner cap and an outer cap, the inner cap having a channel dimensioned to slidably fit the substrate therethrough;

heating each of the sealing rings until the sealing rings reflow;

sliding the substrate through the channel of the inner cap such that one of the conductive wires extends through the bore of the opposite end cap;

mating the outer cap with the inner cap, the outer cap having a bore therethrough so that the other conductive wire extends through the bore of the outer cap;

welding the outer cap to the inner cap circumferentially at the point where the outer cap mates with the inner cap; and

hermetically sealing the end caps to the conductive wires.

14. The method recited in claim 13, wherein the step of forming the D-shaped shell comprises the step of molding liquid glass or glass ceramic into a D-shaped mold.

15. The method, as recited in claim 13, wherein the step of forming the D-shaped shell comprises the step of extruding liquid glass or glass ceramic into a D-shaped mold.

16. The method, as recited in claim 13, wherein the step of forming the D-shaped shell comprises the step of machining glass ceramic or optically clear ceramic into a D-shape.

17. The method, as recited in claim 13, wherein the step of forming a sealing ring comprises the step of forming a glass frit sealing ring about one end of each of the end caps.

18. The method, as recited in claim 13, wherein the step of forming a sealing ring comprises the step of forming a metal sealing ring about one end of each of the end caps.