360-degree flat-surface mechanical stop for lead connector block and setscrew system

• US 7,016,734 B2
• Filed: 05/06/2003
• Issued: 03/21/2006
• Est. Priority Date: 05/06/2003
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Persuitti, Kevin J., Linger, Timothy P., Vang, Toua
• Primary Examiner(s): Bockelman, Mark
• Assistant Examiner(s): BERTRAM, ERIC D
• Application Number:
  US10/430,847
• Publication Number:
  US 20040225334A1
• Time in Patent Office: 1,050 Days
• Field of Search: 607/36, 607/37, 403/362, 292/350, 439/810, 439/814, 411/393
• US Class Current: 607/37
• CPC Class Codes: A61N 1/3752 Details of casing-lead connections
• CPC Class Codes: Y10T 403/7041 including set screw

Abstract

A connector block and associated locking setscrew for an implantable electronic tissue stimulating device are designed to eliminate thread damage to the setscrew which is a cause of the setscrew becoming stuck in the connector block. The threaded bore in the connector that is adapted to receive the setscrew is provided with an undercut at the end of the threaded bore where the undercut provides an annular, 360-degree flat surface that is normal to the longitudinal axis of the setscrew receiving bore. The setscrew employed is designed to have a shoulder machined a predetermined distance below the terminus of the final thread by machining a reduced diameter portion on the distal end of the setscrew. Now, when the setscrew is inserted into its threaded bore, the shoulder on the setscrew and the flat surface on the undercut in the connector block meet, preventing any portion of the screw threads from extending beyond the internal threads formed in the setscrew receiving bore of the connector block.

Claims

1. In an implantable pulse generator of the type including a hermetically sealed housing containing an electrical circuit having input nodes and output nodes, a feed-through assembly having conductive pins connected to the input nodes and output nodes, a header having a longitudinal bore adapted to receive a proximal terminal of a medical lead and at least one electrical connector block disposed in said longitudinal bore and connected to a conductive pin of the feedthrough assembly, the connector block including a first bore through a thickness dimension thereof and generally coaxially aligned with the longitudinal bore, the connector block further including a transversely extending bore that intersects the first bore, the improvement comprising:

(a) internal threads in the transversely extending bore of the connector block extending from an exterior surface of the connector block to an annular-undercut that is disposed a predetermined distance inward of the first bore to form a 360-degree flat surface; and

(b) a setscrew having a proximal end and distal end with external threads on a predetermined portion of the setscrew extending from the proximal end toward, but short of, the distal end and with an unthreaded distal end portion being of a lesser diameter than the predetermined portion that is threaded to define a 360-degree shoulder on the setscrew that is in a plane that is perpendicular to the longitudinal axis of the setscrew, where the 360-degree shoulder is adapted to butt against the 360-degree flat surface of the annular undercut in the connector block when the distal end of the setscrew has entered the first bore of the connector block.

2. The device of claim 1 wherein the annular undercut has a diameter of about 0.090 inch and a length of about 0.010 inch.

3. The device of claim 2 wherein the setscrew has its unthreaded distal portion of about 0.048 inch in diameter and 0.033 inch in length and the shoulder is about 0.0084 inch wide.

4. In combination, a connector block and a lead-locking setscrew for use in a header of an implantable pulse generator comprising:

(a) a connector block having a longitudinal bore adapted to receive a proximal terminal pin of a medical lead therethrough and a stepped transverse bore intersecting the longitudinal bore, the stepped transverse bore being threaded over only a predetermined portion thereof and terminating in a lesser diameter defining an undercut section having an annular planar 360-degree surface that is perpendicular to a central axis of the transverse bore; and

(b) a setscrew having a proximal end and a distal end with external threads on a predetermined portion of the setscrew for mating with the threads in the transverse bore of the connector block in said predetermined portion extending from the proximal end toward, but short of, the distal end and with an unthreaded distal end portion being of a lesser diameter than the predetermined portion that is threaded to define an annular 360-degree shoulder on the setscrew that is in a plane that is perpendicular to a longitudinal axis of the setscrew whereby when the setscrew is screwed into the transverse bore of the connector block, the annular 360-degree shoulder on the setscrew engages the annular, planar, 360-degree surface of the connector block, preventing thread damage or canting of the setscrew.

5. The combination of claim 4 wherein the setscrew further includes a recess in the distal end thereof.