SEAL PLUG

• US 20150018923A1
• Filed: 06/19/2014
• Published: 01/15/2015
• Est. Priority Date: 07/12/2013
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Nolan, Daragh, English, James M., Walsh, Sean, O'Rourke, John
• Granted Patent: US 9,242,107 B2
• Time in Patent Office: Days
• US Class Current: 607/122
• CPC Class Codes: A61N 1/362 Heart stimulators heart defibrillators A61N1/39
• CPC Class Codes: A61N 1/3752 Details of casing-lead connections
• CPC Class Codes: H01R 13/5224 for medical use
• CPC Class Codes: H01R 4/36 Conductive members located under tip of screw
• CPC Class Codes: Y10T 29/49885 with coating before or during assembling

Abstract

An implantable pulse generator includes a core assembly, a seal plug, and an outer layer overmolded over the core assembly adjacent the seal plug. The core assembly defines a core hole extending through the core assembly from a core interior to a core outer surface. The core hole has a hole outer portion and a hole inner portion. A first diameter of the hole outer portion is less than a second diameter of the hole inner portion. The seal plug is positioned in the core hole and has a plug outer portion aligned with the hole outer portion and a plug inner portion aligned with the hole inner portion. A third diameter of the plug outer portion is less than a fourth diameter of the plug inner portion. The outer layer leaves a top of the seal plug exposed.

Claims

1. A pulse generator for use in cardiac rhythm management, the pulse generator comprising:

a device housing containing pulse generator circuitry; and

a header comprising;

a core assembly defining;

a terminal hole extending through the core assembly to allow insertion of a lead terminal into the core assembly; and

a set screw hole extending through the core assembly from a core interior to a core outer surface, the set screw hole having a hole outer portion and a hole inner portion, wherein the core outer surface is nearer the hole outer portion than the hole inner portion, and wherein a first distance across the hole outer portion is less than a second distance across the hole inner portion;

an epoxy outer layer overmolded over the core assembly; and

a seal plug positioned in the set screw hole, wherein the seal plug has a plug outer portion aligned with the hole outer portion and a plug inner portion aligned with the hole inner portion, wherein a third distance across the plug outer portion is less than a fourth distance across the plug inner portion, and wherein a top of the seal plug is exposed by the epoxy outer layer.

2. The pulse generator of claim 1, wherein the seal plug has a substantially frustoconical portion from the plug inner portion to the plug outer portion.

3. The pulse generator of claim 2, wherein the epoxy outer layer covers some but not all of the substantially frustoconical portion of the seal plug.

4. The pulse generator of claim 1, wherein the seal plug has a deformable slit extending through the top of the seal plug through which a tool can be inserted and that is substantially closed to seal and limit fluid flow through the seal plug when the tool is removed.

5. The pulse generator of claim 1, wherein the core assembly comprises:

a core defining the hole inner portion of the set screw hole of the core assembly; and

a collar fixed to the core and having a collar hole defining the hole outer portion of the set screw hole of the core assembly.

6. The pulse generator of claim 5, wherein the collar hole is substantially cylindrical and wherein the first distance is a diameter of the collar hole.

7. The pulse generator of claim 5, wherein the collar is connected to the core via an interference press fit.

8. The pulse generator of claim 5, wherein the core comprises a core rim extending from the core outer surface circumferentially around the set screw hole, wherein the collar comprises a collar rim extending toward the core, and wherein the collar rim is fixed to the core rim via an interference press fit.

9. The pulse generator of claim 1, and further comprising:

a set screw extending through at least a portion of the hole inner portion and covered by the seal plug.

10. The pulse generator of claim 9, wherein the core assembly comprises an electrically insulative polymer and wherein the set screw comprises one or more electrically conductive metals.

11. An implantable pulse generator comprising:

a core assembly defining a core hole extending through the core assembly from a core interior to a core outer surface, the core hole having a hole outer portion and a hole inner portion, wherein a first diameter of the hole outer portion is less than a second diameter of the hole inner portion;

a seal plug positioned in the core hole, wherein the seal plug has a plug outer portion aligned with the hole outer portion and a plug inner portion aligned with the hole inner portion, wherein a third diameter of the plug outer portion is less than a fourth diameter of the plug inner portion; and

an outer layer overmolded over the core assembly adjacent the seal plug and leaving a top of the seal plug exposed.

12. The implantable pulse generator of claim 11, and further comprising:

a threaded fastener extending through at least a portion of the hole inner portion and covered by the seal plug.

13. The implantable pulse generator of claim 12, wherein the threaded fastener has a head connected to a threaded shaft, wherein the seal plug defines a plug cavity, and wherein the head is positioned at least partially in the plug cavity.

14. The implantable pulse generator of claim 13, wherein the seal plug has a deformable slit extending through a top of the seal plug through which a tool can be inserted and that is substantially closed to seal and limit fluid flow through the seal plug when the tool is removed.

15. The implantable pulse generator of claim 11, and further comprising:

a lead bore cavity receptacle positioned inside the core assembly for receiving a lead terminal of an electrical lead; and

a set screw oriented with respect to the lead bore cavity receptacle and configured to be tightened so as to fasten the lead terminal in the lead bore cavity receptacle.

16. The implantable pulse generator of claim 11, wherein an interface between the seal plug and the core assembly is substantially free of medical adhesive.

17. The implantable pulse generator of claim 11, wherein the implantable pulse generator comprises a cardiac resynchronization therapy device for use in cardiac rhythm management.

18. A method of manufacturing a header of a pulse generator, the method comprising:

forming a core assembly defining a core hole extending through the core assembly from a core interior to a core outer surface, the core hole having a hole outer portion and a hole inner portion, and wherein a first distance across the hole outer portion is less than a second distance across the hole inner portion;

inserting a seal pin in the core hole so as to extend partially outside of the core hole past the hole outer portion;

overlaying epoxy resin on the core outer surface adjacent to but not covering the seal pin to form a header body of the header;

removing the seal pin from the core hole in the core assembly; and

pushing a seal plug into the core hole so that the seal plug has a plug outer portion aligned with the hole outer portion and a plug inner portion aligned with the hole inner portion, wherein a third distance across the plug outer portion is less than a fourth distance across the plug inner portion.

19. The method of claim 18, wherein forming the core assembly comprises:

molding a core having a core rim extending from the core outer surface circumferentially around the core hole; and

pressing a collar having a collar rim onto the core rim so as to be attached in an interference fit.

20. The method of claim 18, wherein the seal pin comprises an acetal homopolymer, and wherein the acetal homopolymer repels the epoxy resin when the epoxy resin is overlayed on the core outer surface.