Adjustable magnetic devices and methods of using same

• US 10,349,982 B2
• Filed: 06/10/2014
• Issued: 07/16/2019
• Est. Priority Date: 11/01/2011
• Status: Active Grant

• Current Assignee: Nuvasive Specialized Orthopedics, Inc. (Nuvasive Incorporated)
• Original Assignee: Nuvasive Specialized Orthopedics, Inc. (Nuvasive Incorporated)
• Inventors: Culbert, Brad
• Primary Examiner(s): Harvey, Julianna N
• Application Number:
  US14/301,238
• Publication Number:
  US 20140296919A1
• Time in Patent Office: 1,862 Days
• CPC Class Codes: A61B 17/7002 Longitudinal elements, e.g. rods
• CPC Class Codes: A61B 17/7008 with parts of, or attached to, the longitudinal elements, bearing against an outside of the screw or hook heads, e.g. nuts on threaded rods A61B17/7007 takes precedence
• CPC Class Codes: A61B 17/7016 electric or electromagnetic means
• CPC Class Codes: A61B 17/7037 wherein pivoting is blocked when the rod is clamped
• CPC Class Codes: A61B 17/7046 the screws or hooks being mobile in use relative to the longitudinal element A61B17/702, A61B17/7035 take precedence
• CPC Class Codes: A61B 17/7071 Implants for expanding or repairing the vertebral arch or wedged between laminae or pedicles; Tools therefor
• CPC Class Codes: A61B 17/863 with thread interrupted or changing its form along shank, other than constant taper
• CPC Class Codes: A61B 17/8685 comprising multiple separate parts
• CPC Class Codes: A61B 2017/00212 using remote controls
• CPC Class Codes: A61B 2017/00876 magnetic
• CPC Class Codes: A61B 2017/681 Alignment, compression, or distraction mechanisms
• CPC Class Codes: A61F 2/44 for the spine, e.g. vertebrae, spinal discs

Abstract

A system includes a first pedicle screw, a second pedicle screw, and an adjustable rod having an outer housing coupled to one of the first pedicle screw and the second pedicle screw, the outer housing having a threaded shaft secured to one end thereof extending along an interior portion thereof. The system further includes a hollow magnetic assembly disposed within the outer housing and having a magnetic element disposed therein, the hollow magnetic assembly having an internal threaded surface engaged with the threaded shaft, the magnetic assembly being coupled to the other of the first pedicle screw and the second pedicle screw, wherein the hollow magnetic assembly rotates in response to an externally applied magnetic field to thereby lengthen or shorten the distance between the first pedicle screw and the second pedicle screw.

Claims

1. A system for noninvasive tensioning, comprising:

a rod having a proximal end coupled to a first bone fixation device, and a distal end;

a rod housing configured to receive the distal end of the rod, the rod housing further comprising;

a first end having an internal threaded surface and a second end having a lip;

a first magnetic fastener disposed at the first end of the rod housing, with at least a portion of a surface of the first magnetic fastener threaded and configured to engage the internal threaded surface of the rod housing, the first magnetic fastener further operatively connected to a bushing, the bushing disposed between the first magnetic fastener and the rod; and

a second bone fixation device disposed at the second end of the rod housing, the second bone fixation device having a shank and a head, with at least a portion of the head of the second bone fixation device disposed between the rod and the lip of the rod housing, and with at least a portion of the head of the second bone fixation device contacting the rod; and

an external adjustment device having one or more rotating magnets, the one or more rotating magnets configured to generate a rotating magnetic field;

wherein the first magnetic fastener is configured to rotate in response to the rotating magnetic field generated by the external adjustment device, and wherein rotation of the first magnetic fastener in a first direction generates a torque on the first magnetic fastener which rotates and thereby frictionally engages the rod between the bushing and the second bone fixation device to secure the rod to the rod housing; and

wherein rotation of the first magnetic fastener in a second direction disengages the rod from the rod housing.

2. The system of claim 1, further comprising a first fastener locking component configured to mitigate loosening of said first magnetic fastener from secure engagement with the rod.

3. The system of claim 1, configured to stabilize two vertebrae during fusion.

4. The system of claim 1, at least one of the first bone fixation device and the second bone fixation device comprising a bone screw.

5. The system of claim 1, the first magnetic fastener comprising a radially-poled magnet.

6. The system of claim 1, the bushing comprising a saddle-shaped surface.

7. The system of claim 1, wherein the first magnetic fastener is configured to rotate freely with respect to the bushing.

8. A system for noninvasive adjustment, comprising:

a pedicle screw-based system comprising a first end having a threaded interior surface and a second end having a lip, the pedicle screw-based system configured to selectively couple and decouple with a rod;

a first threaded magnetic element, with at least a portion of the first threaded magnetic element disposed within the threaded interior surface of the first end of the pedicle screw-based system;

a bushing coupled to the first threaded magnetic element, the bushing disposed adjacent to the rod;

a pedicle screw extending from the pedicle screw-based system, the pedicle screw comprising a shank and a head, with at least a portion of the head of the pedicle screw disposed between the rod and the lip of the pedicle screw-based system, and with at least a portion of the head of the second bone fixation device contacting the rod;

wherein rotation of the first threaded magnetic element in a first direction couples the rod between the bushing and the head of the pedicle screw; and

wherein rotation of the first threaded magnetic element in a second direction decouples the rod between the bushing and the pedicle screw based system.

9. The system of claim 8, further comprising a first fastener locking component configured to mitigate loosening of said first threaded magnetic element from secure coupling with the rod.

10. The system of claim 8, wherein:

said pedicle screw-based system is configured to be selectively disposed with respect to at least one vertebral body.

11. The system of claim 8, the first threaded magnetic element further comprising a first magnet bonding component, operably coupling a first magnetic element to a first radially-poled magnet, wherein rotation of said first radially-poled magnet bonded to said first magnet bonding component causes rotation of said first threaded magnetic element.

12. The system of claim 8, further comprising an external adjustment device configured to generate said moving magnetic field, and comprising:

one or more magnets; and

a shaft operably coupled with said one or more magnets, said shaft configured to cause said one or more magnets to rotate to generate said moving magnetic field.

13. The system of claim 8, configured to stabilize two vertebrae during fusion.

14. The system of claim 8, the bushing comprising a saddle-shaped surface.

15. A system for noninvasive tensioning, comprising:

a rod having a proximal end coupled to a first bone fixation device and a distal end coupled to a rod housing, the rod housing comprising;

a first end having an internal threaded surface and a second end having a lip;

a first magnetic fastener disposed at the first end of the rod housing, with at least a portion of a surface of the first magnetic fastener threaded and configured to engage the internal threaded surface of the rod housing, the first magnetic fastener operatively connected to a bushing, the bushing disposed between the first magnetic fastener and the rod; and

a second bone fixation device disposed at the second end of the rod housing, the second bone fixation device having a shank and a head, with at least a portion of the head of the second bone fixation device disposed between the rod and the lip of the rod housing, and with at least a portion of the head of the second bone fixation device contacting the rod; and

an external adjustment device having one or more rotating magnets, the one or more rotating magnets configured to generate a rotating magnetic field;

wherein the first magnetic fastener is configured to rotate in response to the rotating magnetic field generated by the external adjustment device, and wherein rotation of the first magnetic fastener in a first direction generates a torque on the first magnetic fastener which rotates and thereby frictionally engages the rod between the bushing and the second bone fixation device to secure the rod to the rod housing; and

wherein rotation of the first magnetic fastener in a second direction disengages the rod from the rod housing.

16. The system of claim 15, configured to stabilize two vertebrae during fusion.

17. The system of claim 15, at least one of the first bone fixation device and the second bone fixation device comprising a bone screw.

18. The system of claim 15, the first magnetic fastener comprising a radially-poled magnet.

19. The system of claim 15, the bushing comprising a saddle-shaped surface.

20. The system of claim 15, wherein the first magnetic fastener is configured to rotate freely with respect to the bushing.