Lumbar disc replacement implant for posterior implantation with dynamic spinal stabilization device and method

• US 20080269904A1
• Filed: 04/26/2007
• Published: 10/30/2008
• Est. Priority Date: 04/26/2007
• Status: Active Grant

• Current Assignee: Rand M. Voorhies
• Original Assignee: Rand M. Voorhies
• Inventors: Voorhies, Rand M.
• Granted Patent: US 8,241,362 B2
• Time in Patent Office: Days
• US Class Current: 606/86A
• CPC Class Codes: A61B 17/7026 with a part that is flexible due to its form
• CPC Class Codes: A61B 17/7031 made wholly or partly of flexible material
• CPC Class Codes: A61B 17/7043 with a longitudinal element fixed to one or more transverse elements which connect multiple screws or hooks
• CPC Class Codes: A61B 17/7055 connected to sacrum, pelvis or skull
• CPC Class Codes: A61B 17/7068 Devices comprising separate rigid parts, assembled in situ, to bear on each side of spinous processes; Tools therefor
• 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: A61F 2/4425 made of articulated components
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2002/30331 made by longitudinally pushing a protrusion into a complementarily-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2002/3037 Translation along the common longitudinal axis, e.g. piston
• CPC Class Codes: A61F 2002/30387 Dovetail connection
• CPC Class Codes: A61F 2002/30397 Limited lateral translation of the rib within a larger groove
• CPC Class Codes: A61F 2002/30398 Sliding
• CPC Class Codes: A61F 2002/304 with additional means for limiting said sliding
• CPC Class Codes: A61F 2002/30507 using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/30523 by means of meshing gear teeth
• CPC Class Codes: A61F 2002/30538 for adjusting angular orientation
• CPC Class Codes: A61F 2002/3054 about a connection axis or implantation axis for selecting any one of a plurality of radial orientations between two modular parts, e.g. Morse taper connections, at discrete positions, angular positions or continuous positions
• CPC Class Codes: A61F 2002/30604 modular
• CPC Class Codes: A61F 2002/448 comprising multiple adjacent spinal implants within the same intervertebral space or within the same vertebra, e.g. comprising two adjacent spinal implants
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0033 : made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2250/0006 : for adjusting angular orientation

Abstract

The invention consists of disc replacement implant for the lumbar spine designed for insertion into the disc space via a posterior approach. The implant can be stabilized in the disc space by connection to the vertebra or can be connected to dynamic spinal stabilization device consisting of interconnected bullets nested in a spring nested in a woven sleeve. By controlling the limits of elongation and compression the device prevents movement beyond normal physiological limits. In the midrange of movement flexibility is allowed. A method for using the dynamic spinal stabilization device is also provided.

Claims

1. A lumbar disc replacement apparatus for posterior implantation in the disc space between a patient'"'"'s first vertebra and adjacent vertebra comprising:

a lower implant with an upper surface and a lower surface sized and shaped to fit within the disc space of the first vertebra and adjacent vertebra;

an upper implant with an upper surface and a lower surface and shaped in a manner to fit within the disc space of the first vertebra and adjacent vertebra;

wherein the upper implant is slideably engaged with the lower implant within the disc space;

wherein the slideable engagement is along a longitudinal plane of the lower implant upon movement of the first vertebra in relation to the adjacent vertebra;

wherein the lower implant and upper implant are shaped in a manner to prevent the entire body of the upper implant from sliding completely beyond the projected vertical plane of the body of the lower implant;

wherein the lower implant has an anchor rail with a base, midbody and top end with the base of the anchor rail attached to the lower implant in a manner that the top end of the anchor rail projects outside of the disc space for operative attachment of the top end of the anchor rail to the spine.

2. The lumbar disc replacement apparatus for posterior implantation of claim 1:

wherein the upper implant and lower implant are slideably engaged by a tongue and groove joint disposed on the upper implant and lower implant.

3. The lumbar disc replacement apparatus for posterior implantation of claim 1:

wherein the top end of the anchor rail is operatively connected to a dynamic spinal stabilization device.

4. The lumbar disc replacement apparatus for posterior implantation of claim 1:

wherein the bottom surface of lower implant has a plurality of projections that extend out from the horizontal plane of the bottom surface in a manner to secure the lower implant to the first vertebra;

wherein the upper surface of the upper implant has a plurality of projections that extend out from the horizontal plane of the upper surface in a manner to secure the upper implant to the adjacent vertebra.

5. The lumbar disc replacement apparatus for posterior implantation of claim 1:

wherein the upper implant has a front end and back end, and the upper implant has a central longitudinal passage disposed completely through the upper implant from the front end to the back end;

wherein the lower implant has a front end and back end;

wherein the anchor rail'"'"'s midbody is attached to the front end of the lower implant and the base end of the anchor rail attached to the back end of the lower implant with a guide rail formed on the anchor rail between the base end attachment and the midbody attachment wherein the guide rail is disposed through the central longitudinal passage of the upper implant in a manner that allows the upper implant to be slidably engaged along the guide rail.

6. The lumbar disc replacement apparatus for posterior implantation of claim 5:

wherein the upper surface of the lower implant has a dome shape and the bottom surface of the upper implant is shaped to fit flush with the upper surface of the lower implant and the bottom surface of the upper implant is slideably engaged with upper surface of lower implant when the upper implant moves along the guide rail.

7. The lumbar disc replacement apparatus for posterior implantation of claim 5, further comprising:

wherein lower implant has a bottom section and a top section;

wherein the top section of the lower implant is rotatably engaged with the bottom section of the lower implant.

8. The lumbar disc replacement apparatus for posterior implantation of claim 7:

wherein the rotatable engagement is by means of a gear mechanism.

9. The lumbar disc replacement apparatus for posterior implantation of claim 8:

wherein the gear mechanism includes a locking device that provides the meansito fix to orientation of the top section of the lower implant with respect to the bottom section of the lower implant.

10. The lumbar disc replacement apparatus for posterior implantation of claim 1:

wherein lower implant has a bottom section and a top section;

wherein the top section of the lower implant is rotatably engaged with the bottom section of the lower implant.

11. The lumbar disc replacement apparatus for posterior implantation of claim 10:

wherein the rotatable engagement is by means of a locking gear mechanism.

12. The lumbar disc replacement apparatus for posterior implantation of claim 10:

wherein the upper implant is slideably engaged to the lower implant by a tongue and groove joint.

13. A method of posterior removal of a patient'"'"'s lumbar disc and implantation of artificial disc, comprising the following steps:

exposing posterior aspect of patient'"'"'s spine including spinous process, lamina and facet joints;

performing a laminectomy;

removing at least one facet joint;

removing the spinal disc of the patient;

inserting one or more artificial disc implants within the patient'"'"'s disc space with each disc implant having an upper implant and lower implant and an anchor shaft having a base end, midbody and top end with the base of the anchor shaft attached to the lower implant in a manner that the top end of the anchor shaft projects outside of the vertebra disc space for attachment to a vertebra wherein the upper implant is slideably engaged to the lower implant in a manner that allows movement of the upper vertebra and lower vertebra and wherein the slideable engagement occurs upon movement of the upper vertebra and lower vertebra and wherein the lower implant is shaped in a manner to prevent the upper implant from sliding beyond the projected volume of the lower implant; and

attaching the top end of the anchor shaft to a spinal stabilization device.

14. The method of posterior removal of lumbar disc and implantation of artificial disc of claim 13 further comprising the following steps:

inserting lower implant within one side of disc space;

inserting upper implant having a central longitudinal passage within opposite side of disc space in a manner that the upper implant is slideably engaged with the lower implant upon movement of the upper vertebra and lower vertebra;

inserting the anchor rod through the central passage contained within the upper implant in a manner that the upper implant is slideably disposed along the anchor rod;

securing the base end of anchor rod to the lower implant; and

securing midbody of the anchor rod to the lower implant.

15. The method of posterior removal of lumbar disc and implantation of artificial disc of claim 13, further comprising the following steps:

implanting upper and lower implant wherein the lower implant has a bottom section and an top section rotatably connected to each other by a locking gear mechanism;

anchoring the implant to a part of the spinal stabilization device;

rotating the gear mechanism to orient the top section of the lower implant in a manner that the top section lines up with the sagittal plane of the spine;

locking the gear mechanism.

16. The method of posterior removal of lumbar disc and implantation of artificial disc of claim 13, further comprising the following steps:

attaching the top end of the anchor shaft to a transverse rod;

attaching the transverse rod to a first portion of patient'"'"'s spine;

attaching a dynamic stabilization device to the transverse rod;

attaching the dynamic stabilization device to a second transverse rod; and

attaching second transverse rod to a second portion of patient'"'"'s spine.

17. An apparatus for stabilizing a patient'"'"'s spine comprising:

a plurality of bullets with each bullet having an upper side and a lower side wherein the bullet'"'"'s upper side is sized and configured to insert into an adjacent bullet'"'"'s lower side in a manner forming a rod;

wherein, a top bullet is on the top of the rod and a bottom bullet is on the bottom of the rod;

an extension spring that resists elongation wherein said extension spring is disposed around and encases the rod and the extension spring is attached to the rod in a manner to resist separation of the individual bullets;

wherein, upon elongation of the extension spring, the bullets'"'"' upper sides withdraw from the adjacent bullets'"'"' lower sides allowing the bullets to move and bend in all planes with respect to the adjacent bullets;

wherein, the top bullet is attached to a part of a patient'"'"'s spine by an attachment means and the bottom bullet is attached to a second part of the patient'"'"'s spine by an attachment means.

18. The apparatus for stabilizing a patient'"'"'s spine of claim 17,

wherein each bullet is attached to the adjacent bullet by a flexible attachment material to flexibly attach the bullets together in a manner to provide for terminal elongation of the rod;

further comprising a top attachment element attached to the top bullet;

a bottom attachment element attached to the lower bullet.

19. The apparatus for stabilizing a patient'"'"'s spine of claim 17,

wherein, the bullets'"'"' upper sides are conically shaped.

20. The apparatus for stabilizing a patient'"'"'s spine of claim 17,

wherein, the bullets'"'"' upper sides have a curved hook projection.

21. The apparatus for stabilizing a patient'"'"'s spine of claim 20,

wherein the curved hook projection has a curved top edge, and the bullets have a cavity formed by recessed walls of the lower side of the bullet with the recess sized and shaped to allow insertion of an adjacent bullet'"'"'s curved hook projection in a manner that the bullets are rigid when the curved hook is fully inserted into the lower side of an adjacent bullet and upon elongation of the spring, the curved hook projection partially withdraws from the lower side of an adjacent bullet in a manner that allows bending and movement of the bullets with one another along the curved top edge of the curved hook projection;

wherein one of the recessed walls of the lower side of the bullet has a ridge sized and configured in a manner to prevent the curved hook from moving completely out of the cavity upon elongation and bending of the bullets providing terminal elongation of the rod.

22. The apparatus for stabilizing a patient'"'"'s spine of claim 17,

wherein, the bullet'"'"'s upper side forms a flat arrow shape.

wherein, the flat arrow shape having at least four edges with two opposite edges of the flat arrow tapering to a narrower distal end and at least two of the remaining edges of the flat arrow upper side having flat planar edges parallel to each other and upon partial insertion of the flat arrow within an adjacent bullet'"'"'s lower side, the bullets move along the perpendicular planes of the tapered edges and the bullets have restricted movement perpendicular to the plane of the parallel sides;

wherein the flat planar sides are shaped to restrict complete withdrawal from the cavity of the adjacent bullet'"'"'s lower side upon elongation of the bullets providing for terminal elongation of the bullets.

23. The apparatus for stabilizing a patient'"'"'s spine of claim 17,

further comprising a sleeve of woven material disposed around and encases the extension spring in a manner that provides an elongation limit to the spring;

wherein, the sleeve is in a loose weave pattern when the extension spring is in a resting, non elongated state and upon elongation of the extension spring, the sleeve elongates, tightening the sleeve'"'"'s woven material resulting in a constricted diameter of the sleeve.

24. The apparatus for stabilizing a patient'"'"'s spine of claim 23,

further comprising a compression spring disposed around and encases the sleeve of woven material and bullets in a manner to resist compression of the bullets with respect to each other.

25. The apparatus for stabilizing a patient'"'"'s spine of claim 17,

wherein, the bullets have a generally uniform lateral curved shape in a manner that forms a curved rod shape.

26. The apparatus for stabilizing a patient'"'"'s spine of claim 17,

further comprising a guide wire;

wherein, the bullets have a central passage disposed from the bullet'"'"'s top side to the bullet'"'"'s bottom side with the passage sized for insertion of the central guide wire with the central guide wire disposed through the bullets'"'"' aligned central passages.

27. The apparatus for stabilizing a patient'"'"'s spine of claim 17,

wherein the attachment means to connect the bullets to the spine comprises a first transverse rod and second transverse rod with each transverse rod having a first end and second end and a midbody wherein the top bullet is attached to the midbody of the first transverse rod and the first end of the first transverse rod is attached to a part of the patient'"'"'s spine and the second end of the first transverse rod is attached to a second part of the patient'"'"'s spine and the bottom bullet is attached to the midbody of the second transverse rod wherein first end of the second transverse rod is attached to a third part of the patient'"'"'s spine and the second end of the second transverse rod is attached to a fourth part of the patient'"'"'s spine.

28. The apparatus for stabilizing a patient'"'"'s spine of claim 27,

wherein, at least one of the transverse rods is shaped and attached to one of the bullets in a manner that the distance between the first end of the first rod and the first end of the second rod is less than the length of the interconnected bullets.

29. The apparatus for stabilizing a patient'"'"'s spine of claim 17,

wherein, the attachment means that attaches the rod to the spine comprises a first plate and a second plate with each plate having a midbody and the first plate and second plate are attached a patient'"'"'s spinous process;

30. The apparatus for stabilizing a patient'"'"'s spine of claim 29 further comprising,

a first bumper attached to the first plate;

a third plate and a fourth plate;

a second bumper attached to the third plate;

wherein the third plate and fourth plate are attached to an adjacent spinous process;

wherein the first bumper and second bumper fit snugly adjacent to each other.

31. An apparatus for stabilizing a patient'"'"'s spine comprising:

a plurality of interconnected bullets with each bullet having an upper side and lower side wherein the lower bullets'"'"' lower sides are sized and configured to allow insertion of an adjacent bullet'"'"'s upper side in an interconnected manner forming a stack of bullets in a rod shape and said stack of bullets are generally rigid and resist bending when each of the bullet'"'"'s upper side is fully inserted into adjacent bullet'"'"'s lower side;

a spring that resists elongation is disposed around the stack of bullets and said spring encases and is attached to the stack of bullets in a manner to resist separation of the stack of bullets and promotes rigidity of the stack of bullets;

wherein, upon elongation of the spring, the bullet'"'"'s upper side withdraws from the adjacent bullet'"'"'s lower side allowing the stacked bullets to move and bend with respect to the adjacent bullets;

a sleeve of woven material that encases the spring in a loose weave pattern when the spring is in a resting state with the bullets stacked in a full insertion and rigid manner and when the spring is elongated the sleeve'"'"'s weave pattern tightens resulting in a constricted diameter and wherein the sleeve is attached to the spring or to at least one of the bullets in a manner to provide an absolute limit on the spring'"'"'s elongation and imparting some rigidity to the stacked bullets and spring.

32. The apparatus for stabilizing a patient'"'"'s spine of claim 31,

wherein, the bullets have a central passage disposed from the bullet'"'"'s top side to the bullet'"'"'s bottom side and said central passage is sized for placement of a central guide wire;

a compression spring that encases the sleeve of woven fabric and the compression spring is attached to the stack of bullets in a manner that resists compression of the bullets with respect to each other;

33. A method for dynamic spine stabilization comprising the steps of:

exposing the vertebrae to be stabilized;

attaching one end of a stack of bullets to the vertebra wherein said stack of bullets are nested in an elongation resistant spring in a manner that provides a terminal elongation of the stack of bullets and wherein said spring is nested in a sleeve of elongation resistant material in a manner that provides some rigidity upon elongation of the elongation resistant spring;

attaching the one end of said stack of bullets to a part of the patient'"'"'s spine attaching opposite end of said stack of bullets to a second part of patient'"'"'s spine.

34. The method for dynamic spine stabilization as recited in claim 33,

further comprising the steps of securing one end of a first stack of bullets to one side of a spinous process,

securing one end of second stack of bullets to opposite side of a spinous process;

securing opposite end of first stack of bullets to one side of second spinous process;

securing opposite end of second stack of bullets to opposite side of second spinous process.

35. The method for dynamic spine stabilization as recited in claim 33, further comprising the steps of:

securing one end of a first transverse rod to one side of first vertebra;

securing opposite end of first transverse rod to opposite side of first verterbra;

securing one end of second transverse rod to one side of second vertebra;

securing opposite end of second transverse rod to opposite side of second vertebra;

attaching one end of said interconnected stack of bullets to midbody of first transverse rod;

attaching opposite end of said interconnected stack of bullets to midbody of second transverse rod.

36. The method for dynamic spine stabilization as recited in claim 35, further comprising the step of:

attaching third transverse rod to third vertebra;

attaching end of a second stack of interconnected bullets to midbody of second transverse rod;

attaching opposite end of second stack of interconnected bullets to midbody of third transverse rod.