Implantable Medical Sensor and Fixation System

• US 20120108986A1
• Filed: 04/20/2011
• Published: 05/03/2012
• Est. Priority Date: 10/29/2010
• Status: Active Grant

• Current Assignee: Medtronic Vascular, Inc. (Medtronic Plc)
• Original Assignee: Medtronic Vascular, Inc. (Medtronic Plc)
• Inventors: Beasley, Rudy, Griswold, Erik, Allan, James Calvin, Patras, George, Mothilal, Kamal Deep, Dunfee, Albert
• Granted Patent: US 8,864,676 B2
• Time in Patent Office: Days
• US Class Current: 600/486
• CPC Class Codes: A61B 2560/066 catheters therefor
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• CPC Class Codes: A61B 5/02055 Simultaneously evaluating both cardiovascular condition and temperature
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/029 Measuring or recording blood output from the heart, e.g. minute volume A61B8/065 takes precedence
• CPC Class Codes: A61B 5/6876 Blood vessel
• CPC Class Codes: A61B 5/6879 Means for maintaining contact with the body A61B5/6847 takes precedence
• CPC Class Codes: A61B 5/6884 Clamps or clips
• CPC Class Codes: A61N 1/37205 Microstimulators, e.g. implantable through a cannula

Abstract

An implantable medical device, such as a sensor for monitoring a selected internally detectable physiological parameter of a patient, is attached to a fixation member that is deployable within the patient to position and orient the sensor to enable it to perform its function. The fixation member may be configured to lie in a single plane when deployed or may be tubular in shape. The attachment of the housing and fixation member includes providing the fixation member with a linear attachment strut that is non-circular in cross section and providing the housing with external members that define an elongate channel, non-circular in cross section and receptive to the attachment strut. The attachment strut can be inserted transversely into the channel and the external member can be crimped over the strut to secure the housing and fixation member together.

Claims

1. An implantable sensor assembly comprising:

a wire-like fixation member expandable from a low profile configuration to an expanded configuration adapted to engage the wall of a vessel to maintain its position in the vessel, the fixation member having proximal and distal ends, at least the distal end comprising a loop, and an elongate, linear attachment strut extending proximally from the loop, the loop and strut lying substantially in a single common plane;

a sensor housing containing sensing elements adapted to sense a physiological parameter within the vessel of a patient, the housing having proximal and distal ends and a longitudinal sidewall extending between the ends;

the sensor housing including a connector extending along its sidewall, the connector being attached securely and directly to the attachment strut.

2. The implantable sensor assembly as defined in claim 1 further comprising a second loop formed at the proximal end of the fixation member, the second loop being connected to the proximal end of the attachment strut and lying substantially in the common plane.

3. The implantable sensor assembly as defined in claim 2 wherein the attachment strut is sufficiently long to enable the sensor housing to be disposed between and embraced by the proximal and distal loops.

4. The implantable sensor assembly as defined in claim 2 wherein the attachment strut is shorter than the sensor housing and longer than the connector.

5. The implantable sensor assembly as defined in claim 1 wherein the sensor housing is attached to the attachment strut to intersect the common plane.

6. The implantable sensor assembly as defined in claim 1 wherein the sensor housing is attached to the attachment strut and spaced from the common plane.

7. The implantable sensor assembly as defined in claim 1 wherein the connector and attachment strut are configured to prevent relative rotation of the housing about the strut.

8. The implantable sensor assembly as defined in claim 3 wherein the sensor housing has a sensing element at its surface, the surface sensing element being intersected by the common plane.

9. The implantable sensor assembly as defined in claim 1 wherein the sensor housing has a sensing element at its surface, the sensing element being spaced from the common plane.

10. The implantable sensor assembly as defined in claim 2 wherein each loop has a teardrop shape in its expanded configuration, the narrow end of the teardrop shape being disposed at the junction of the loop and the attachment strut.

11. The implantable sensor assembly as defined in claim 10 wherein the teardrop shape is defined by a pair of loop segments connected by a bight segment, the inner ends of the loop segments meeting at a junction angle that is no greater than about 90 degrees.

12. The implantable sensor assembly as defined in claim 10 wherein each loop is resiliently compressible to a smaller profile defined by a pair of loop segments arranged in approximately paralleling relation.

13. The implantable sensor assembly as defined in claim 1 wherein the fixation member has superelastic properties.

14. The implantable sensor assembly as defined in claim 13 wherein the fixation member comprises a nitinol alloy.

15. The implantable sensor assembly as defined in claim 13 adapted for placement in a selected region of a human pulmonary artery tree, the selected region having a predetermined effective diameter, the distal loop having a relaxed height approximately twenty percent greater than the predetermined effective diameter at the selected region.

16. The implantable sensor assembly as defined in claim 15 wherein the predetermined effective diameter is about ten millimeters and the height of the distal loop is about twelve millimeters.

17. The implantable sensor assembly as defined in claim 1 wherein the connector is formed integrally with the housing.

18. The implantable sensor assembly as defined in claim 1 wherein the loop is continuous.