Minimally Invasive Physiologic Parameter Recorder and Introducer System

• US 20090192381A1
• Filed: 01/30/2009
• Published: 07/30/2009
• Est. Priority Date: 01/30/2008
• Status: Active Grant

• Current Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Original Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Inventors: Brockway, Brian P., Mills, Perry A.
• Granted Patent: US 8,180,438 B2
• Time in Patent Office: Days
• US Class Current: 600/373
• CPC Class Codes: A61B 2560/0219 of externally powered implanted units
• CPC Class Codes: A61B 2560/063 Devices specially adapted for delivering implantable medical measuring apparatus
• CPC Class Codes: A61B 2560/066 catheters therefor
• CPC Class Codes: A61B 2562/164 the sensor is mounted in or on a conformable substrate or carrier
• CPC Class Codes: A61B 2562/18 Shielding or protection of sensors from environmental influences, e.g. protection from mechanical damage
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/076 Permanent implantations telemetry using implanted circuitry A61B5/0031; implanted stimulators for therapy A61N1/3605, A61N1/362, A61N1/372
• CPC Class Codes: A61B 5/283 Invasive
• CPC Class Codes: A61B 5/287 Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS]
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61B 5/7232 involving compression of the physiological signal, e.g. to extend the signal recording period
• CPC Class Codes: A61N 1/0504 Subcutaneous electrodes
• CPC Class Codes: A61N 1/37229 Shape or location of the implanted or external antenna
• CPC Class Codes: A61N 1/375 Constructional arrangements, e.g. casings
• CPC Class Codes: A61N 1/3756 Casings with electrodes thereon, e.g. leadless stimulators
• CPC Class Codes: A61N 1/3787 from an external energy source

Abstract

An implantable monitoring device includes a flexible lead body that includes at least one sensing element. The device also includes a rigid main body connected to the flexible lead body at an attachment point. The rigid main body is generally centered about a longitudinal axis defined by the flexible lead body when the lead body is unflexed. The device further includes a measurement circuit, which is housed within the rigid main body and electrically coupled to the at least one sensing element of the flexible lead body and at least another sensing element on an outside surface of the rigid main body. The measurement circuit is configured to measure a potential difference between the at least one sensing element of the flexible lead body and the at least another sensing element of the main body.

Claims

1. An implantable monitoring device, comprising:

a flexible lead body that includes at least one sensing element;

a rigid main body connected to the flexible lead body at an attachment point, the rigid main body generally centered about a longitudinal axis defined by the flexible lead body when the lead body is unflexed; and

a measurement circuit, housed within the rigid main body and electrically coupled to the at least one sensing element of the flexible lead body and at least another sensing element on an outside surface of the rigid main body, and configured to measure a potential difference between the at least one sensing element of the flexible lead body and the at least another sensing element of the main body.

2. The implantable monitoring device of claim 1, wherein a portion of the rigid main body tapers from a first width to a second width narrower than the first width.

3. The implantable monitoring device of claim 2, wherein the portion tapers symmetrically about a longitudinal axis of the rigid main body.

4. The implantable monitoring device of claim 2, wherein the portion tapers approximately linearly from the first width to the second width.

5. The implantable monitoring device of claim 2, wherein the portion tapers non-linearly from the first width to the second width.

6. The implantable monitoring device of claim 1, wherein a first portion of the rigid main body tapers approximately linearly from a first width to a second width narrower than the first width, and a second portion of the rigid main body tapers non-linearly from a third width to a fourth width narrower than the third width.

7. The implantable monitoring device of claim 1, wherein the rigid main body comprises at least a first housing section that is hermetically sealed and a second housing section that is not hermetically sealed.

8. The implantable monitoring device of claim 7, wherein a width of a proximal section of the second housing section is substantially greater than a width of a distal section of the second housing.

9. The implantable monitoring device of claim 1, further comprising a loop member on a proximal portion of the rigid body.

10. The implantable monitoring device of claim 9, wherein the loop member is used to suture the device to body tissue.

11. The implantable monitoring device of claim 9, wherein the device is extracted from an implant location by applying a withdrawal force to the loop member.

12. An implantable monitoring device, comprising:

a flexible lead body;

a rigid main body connected to the flexible lead body at an attachment point, the rigid main body generally centered about a longitudinal axis defined by the flexible lead body when the lead body is unflexed, wherein the rigid main body comprises a tapered portion proximate the lead body, the tapered portion having smaller width nearer the lead body; and

a measurement circuit, housed within the rigid main body and electrically coupled to at least one sense electrode on the flexible lead body and at least another sense electrode on an outside surface of the rigid main body, and configured to measure a potential difference between the at least one sense electrode on the flexible lead body and the at least another sense electrode on the main body.

13. A method of implanting a monitoring device subcutaneously in a body of a patient, the method comprising:

assembling an introducer, comprising a sheath and a semi-flexible insert, by placing the semi-flexible insert within the sheath, the semi-flexible insert sized and shaped at least in part to match a size and shape of the monitoring device, the semi-flexible insert and the monitoring device each including a tapered section that tapers from a first width at a proximal end of the section to a second width, smaller than the first width, at a distal end of the section;

introducing a distal end of the introducer through an incision in the patient'"'"'s skin to a desired subcutaneous implant location site beneath the patient'"'"'s skin;

withdrawing the semi-flexible insert from the sheath without substantially disturbing the position of the sheath at the desired subcutaneous implant location site;

inserting the monitoring device into the sheath; and

withdrawing, in a direction opposite that which it was introduced, the sheath from the implant location site while applying pressure to the monitoring device, wherein an external surface of the sheath splits along an axis as the sheath surface is forced against the tapered section of the monitoring device while the sheath is being withdrawn.

14. The method of claim 13, wherein at least a portion of the sheath is sized and shaped in proportion to a corresponding portion of the semi-flexible insert.

15. The method of claim 13, wherein the distal end of the introducer deflects upon contacting a surface of a muscle layer and slides across the surface of the muscle layer without penetrating the muscle layer.

16. The method of claim 13, wherein the external surface of the sheath includes a surface modification along at least a portion of the axis, the surface modification reducing a tensile strength of the external surface of the sheath along the axis.

17. An introducer system for implanting, within a body of a patient, a monitoring device that includes a tapered section that tapers from a first width at a proximal end of the section to a smaller second width at a distal end of the section, at a subcutaneous implant location site within the body of the patient, the system comprising:

a semi-flexible insert, at least a portion of which is substantially sized and shaped to match a portion of the monitoring device, including the tapered section;

a sheath sized and shaped to separately receive, within a space defined by an internal surface of the sheath, the semi-flexible insert and the monitoring device, the sheath being splittable along a longitudinal axis of the sheath to facilitate removal of the sheath from the subcutaneous implant location site.

18. The introducer system of claim 17, wherein a distal portion of the sheath is sized and shaped in proportion to a corresponding distal portion of the semi-flexible insert.

19. The introducer system of claim 17, wherein the sheath is more flexible than the semi-flexible insert, and wherein a distal portion of the semi-flexible insert has sufficient rigidity to avoid substantial deflection when directed through a fatty tissue layer of the patient, and sufficient flexibility to, upon contacting a surface of a muscle layer of the patient, deflect and slide across the surface of the muscle layer without penetrating the muscle layer.

20. The introducer system of claim 17, wherein an external surface of the sheath includes a surface modification along at least a portion of the longitudinal axis, the surface modification reducing a tensile strength of the external surface of the sheath along the longitudinal axis.

21. The introducer system of claim 17, further comprising a rod member preformed to define an arc angle, the rod member being more rigid than the semi-flexible insert, and wherein the semi-flexible insert defines a cavity capable of receiving the rod member.

22. A method of implanting an implantable monitoring device—

which includes a rigid main body and a flexible extension that, when unflexed, is substantially collinear with a longitudinal axis of the rigid main body—

in a subcutaneous implant region of a patient, the method comprising;

introducing an insert device to the subcutaneous region of the patient, the insert device having an internal chamber that is generally in the shape of at least a portion of the implantable monitoring device;

inserting, after the insert device has been introduced to the subcutaneous region, the implantable monitoring device to the internal chamber of the insert device; and

removing the insert device from the subcutaneous region while leaving the implantable monitoring device at the subcutaneous region.

23. The method of claim 22, wherein removing the insert device from the subcutaneous region comprises withdrawing, in a direction opposite that which it was introduced, the insert device from the subcutaneous region while applying pressure to the monitoring device, wherein the insert device includes a surface modification to reduce a tensile strength of the insert device.

24. The method of claim 22, wherein the subcutaneous region is above a pectoral fascia of the patient.

25. The method of claim 22, wherein at least a portion of the subcutaneous region is below a pectoral fascia of the patient.

26. The method of claim 25, wherein the entire subcutaneous region is below the pectoral fascia.