U.S. patent application number 14/171265 was filed with the patent office on 2014-05-29 for steerable spine implant insertion device and method.
This patent application is currently assigned to Coridea LLC. The applicant listed for this patent is Coridea LLC. Invention is credited to Nicholas V. Gately.
Application Number | 20140148907 14/171265 |
Document ID | / |
Family ID | 39303957 |
Filed Date | 2014-05-29 |
United States Patent
Application |
20140148907 |
Kind Code |
A1 |
Gately; Nicholas V. |
May 29, 2014 |
STEERABLE SPINE IMPLANT INSERTION DEVICE AND METHOD
Abstract
A method to insert a spinal implant into a vertebral space, the
method including the steps of: grasping the implant with a distal
end of an implant insertion tool; holding a proximal end of the
implant insertion tool and inserting the implant toward the
vertebral space; and manipulating the proximal end to apply a yaw
movement to the implant while the implant is attached to the tool
and in the vertebral space.
Inventors: |
Gately; Nicholas V.;
(Lambertville, NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Coridea LLC |
New York |
NY |
US |
|
|
Assignee: |
Coridea LLC
New York
NY
|
Family ID: |
39303957 |
Appl. No.: |
14/171265 |
Filed: |
February 3, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11870844 |
Oct 11, 2007 |
8641764 |
|
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14171265 |
|
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60829065 |
Oct 11, 2006 |
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Current U.S.
Class: |
623/17.16 |
Current CPC
Class: |
A61F 2310/00023
20130101; A61F 2002/4629 20130101; A61B 17/1604 20130101; A61B
17/1671 20130101; A61F 2002/30242 20130101; A61F 2/4684 20130101;
A61F 2/4465 20130101; A61F 2002/4627 20130101; A61F 2002/30133
20130101; A61F 2230/0071 20130101; A61F 2/4611 20130101; A61F
2250/0098 20130101; A61F 2002/30593 20130101; A61F 2002/3008
20130101; A61F 2002/30894 20130101; A61B 2017/1602 20130101; A61F
2002/30787 20130101; A61F 2230/0015 20130101; A61F 2250/0006
20130101; A61F 2002/30538 20130101; A61F 2002/3083 20130101; A61F
2220/0025 20130101; A61F 2002/30523 20130101 |
Class at
Publication: |
623/17.16 |
International
Class: |
A61F 2/46 20060101
A61F002/46 |
Claims
1. A method comprising: inserting an implant between portions of
bone, wherein the implant locked at a first angle relative to a
shaft of the instrument; loosening the implant relative to the
shaft; turning the shaft to pivot the implant relative to the
shaft; sensing a predetermined angular position of the implant
relative to the shaft as the shaft is turned, and releasing the
implant from the instrument so that the implant is in position
between the bone.
2. The method of claim 1 wherein the predetermined angular position
is sensed as a ridge on the implant slides across a groove on a cam
surface of the instrument.
3. The method of claim 1 wherein turning the shaft rotates gears
fixed to the shaft across a geared surface on the implant.
4. The method of claim 3 wherein turning the geared shaft pivots
the implant.
5. The method of claim 2 wherein a cam surface is slanted and the
movement of the opposing cam across the cam surface pivots the
implant.
6. A spinal insertion tool comprising: an elongated shaft including
a proximal end region and a distal end region, wherein the distal
end region includes a coupling adapted to be reversibly connected
to a spinal implant and the proximal end region is connected to a
handle, and an elongated sleeve including a proximal end region and
a distal end region, wherein the sleeve is coaxial to and encircles
the elongated shaft, and the distal end region of the sleeve
includes legs configured to engage the spinal implant, and a knob
engaging threads on the proximal end region of the shaft, wherein
the knob moves helically about the shaft towards the distal end
region of the shaft so as to bind against the proximal end region
of the sleeve and thereby advance the legs of the sleeve and moves
helically about the shaft towards the handle so as to release the
proximal end region of the sleeve and allow the sleeve to slide
axially over the shaft.
7. The spinal insertion tool of claim 6 wherein the legs are
adjacent the coupling on the shaft while advanced and the legs are
retracted away from the coupling while the sleeve is axially moved
towards the proximal end region.
8. The spinal insertion tool of claim 6 wherein the legs are on
opposite sides of the shaft.
9. The spinal insertion tool of claim 6 wherein the coupling is a
threaded end of the shaft.
10. A method to surgically insert a spinal implant between vertebra
in a mammalian patient using an insertion tool including a sleeve
and shaft within the sleeve and coaxial to the sleeve, the method
comprising: releasably attaching a pivotable coupling in the spinal
implant to shaft coupling at a distal portion of the shaft;
advancing a distal end of the sleeve to engage the spinal implant
while the distal portion of the shaft is attached to the pivotable
coupling in the spinal implant; inserting the spinal implant
between the vertebra while the pivotable coupling in the spinal
implant is attached to the shaft coupling and the distal portion of
the sleeve engages the spinal implant; positioning the spinal
implant between the vertebra, including pivoting the spinal implant
about the shaft coupling such that the spinal implant makes a yaw
movement with respect to the pivotable coupling, and after making
the yaw movement, releasing the distal portion from the shaft from
the spinal implant and removing the insertion tool from the patient
while the spinal implant remains between the vertebra.
11. The method as in claim 10 wherein advancing the distal end of
the sleeve to engage the spinal implant locks the implant at a
first angle relative to the shaft.
12. An assembly of a spinal implant and an insertion tool to insert
the spinal implant between vertebras wherein the insertion tool
comprising: a shaft assembly including a hollow tube concentric
with a rod; a distal portion of the rod including a coupling for
releasably attaching to the spinal implant; a distal portion of the
hollow tube including legs adapted to engage the spinal implant,
and a proximal region of the shaft assembly including a knob
engaging threads on the rod, wherein the knob moves helically to
bind against the distal potion of the hollow tube and to retract to
allow the tube to slide axially over the shaft, and the spinal
implant comprising: a pivoting pin within a housing on the implant,
the pivoting pin adapted to couple to the coupling of the distal
portion of the rod, and a surface of the implant adjacent the
pivoting pin configured to engage the legs of the hollow tube.
13. The assembly in claim 12 wherein the surface of the implant
includes surfaces on opposite sides of the pivoting pin.
14. The assembly in claim 12 wherein the pivoting pin includes an
aperture configured to receive the distal portion of the rod.
15. The assembly in claim 14 wherein the cam aperture includes
threads configured to engage threads on the distal portion of the
rod.
16. The assembly as in claim 12 where the spinal implant includes
an upper surface and a lower surface each adapted to engage one of
the vertebras.
Description
RELATED APPLICATIONS
[0001] This application is a divisional of U.S. application Ser.
No. 11/870,844 (U.S. Pat. No. 8,641,764) filed Oct. 11, 2007, and
claims the benefit of the filing date of U.S. Provisional Patent
Application Ser. No. 60/829,065, filed on Oct. 11, 2006, the
entireties of these applications are incorporated by reference.
BACKGROUND OF INVENTION
[0002] The present invention generally relates to the field of
medical devices. Some embodiments of the invention relate to spinal
implants inserted in the spine of a patient during surgical
procedures and to instruments used to insert the implants. Other
embodiments of the invention relate to methods for positioning,
rotating and advancing an implant during a surgical procedure.
[0003] A spinal implant may be used to stabilize a portion of a
spine. The implant may promote bone growth between adjacent
vertebra that fuses the vertebra together. The implant may include
a spherical protrusion, a threaded pin and an angled surface to
facilitate remote adjustment of the implant position using an
insertion instrument.
[0004] The insertion instrument may include, but is not limited to,
a threaded rod, an actuator and a lock knob. The insertion
instrument can be attached and detached to the implant, rotate the
implant by transferring torque from the actuator to the implant.
The actuator can be used to lock the implant in relation to the
instrument. The rod can be used to apply force to the implant and
advance it. The implant and instruments may be supplied in an
instrument kit.
[0005] An intervertebral disc may degenerate. Degeneration may be
caused by trauma, disease, and/or aging. An intervertebral disc
that becomes degenerated may have to be partially or fully removed
from a spinal column. Partial or full removal of an intervertebral
disc may destabilize the spinal column. Destabilization of a spinal
column may result in alteration of a natural separation distance
between adjacent vertebra. Maintaining the natural separation
between vertebra may prevent pressure from being applied to nerves
that pass between vertebral bodies. Excessive pressure applied to
the nerves may cause pain and nerve damage.
[0006] During a spinal fixation procedure, a spinal implant may be
inserted in a space created by the removal or partial removal of an
intervertebral disc between adjacent vertebra. The spinal implant
may maintain the height of the spine and restore stability to the
spine. Bone growth may fuse the implant to adjacent vertebra.
[0007] A spinal implant may be inserted during a spinal fixation
procedure using an anterior, lateral, posterior, or transverse
spinal approach. A discectomy may be performed to remove or
partially remove a defective or damaged intervertebral disc. The
discectomy may create a space for a spinal implant. The amount of
removed disc material may correspond to the size and type of spinal
implant to be inserted.
[0008] Spinal implants are described in U.S. Pat. No. 5,653,763 to
Errico et al.; U.S. Pat. No. 5,713,899 to Marney et al.; U.S. Pat.
No. 6,143,033 to Paul et al.; U.S. Pat. No. 6,245,108 to Biscup;
and U.S. Pat. No. 5,609,635 to Michelson, United States Patent
Application 20050027360 to Webb.
BRIEF DESCRIPTION OF THE INVENTION
[0009] A spinal implant is disclosed comprising: a top, wherein at
least a portion of the top is configured to contact a first
vertebra; a bottom, wherein at least a portion of the bottom is
configured to contact a second vertebra and a side having a
releasable attachment to receive an insertion device and a cam
surface to engage a cam on the insertion device. The spinal implant
may include a hemispherical mount and a pin mounted within the
spinal implant, wherein the insertion device attaches to the pin
that serves as an axis of rotation and pivots around the pin with
respect to the hemispherical housing.
[0010] A method is disclose comprising: inserting an implant
between portions of bone, wherein the implant locked at a first
angle relative to a shaft of the instrument; loosening the implant
relative to the shaft; turning the shaft to pivot the implant
relative to the shaft, and releasing the implant from the
instrument so that the implant is in position between the bone.
Turning the shaft rotates a cam fixed to the shaft across a cam
surface on the implant, wherein the cam surface is slanted and the
movement of the cam across the cam surface pivots the implant.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a top-side perspective view of a spinal implant
attached to an insertion instrument.
[0012] FIG. 2 is an exploded view showing the spinal implant
separate from the insertion instrument.
[0013] FIG. 3 is a perspective view of the FIG. 3 illustrates the
interaction between the actuator 202 of the instrument and the
implant 100.
[0014] FIG. 4 is a perspective view of the implant releasably
attached to the insertion instrument and positioned over a
vertebra.
[0015] FIGS. 5A, 5B, 5C, 5D and 5E show a side view of a first
alternative spinal implant tool (FIG. 5A), a perspective view of
the actuator for the tool (FIG. 5B), an enlarged view of the distal
end of the actuator (FIG. 5C), a perspective view of the spinal
implant (FIG. 5D) and an enlarged view of the distal end with a
spinal implant attached to the actuator (FIG. 5E).
[0016] FIGS. 6A, 6B and 6C show a side view of an second
alternative spinal implant tool (FIG. 6A), a perspective view of
the distal end of tool attached to a spinal implant (FIG. 6B), and
a second perspective view of the distal end of tool attached to a
spinal implant (FIG. 6C).
[0017] FIGS. 7A and 7B show a side view of a third alternative
spinal implant tool (FIG. 7A), and a perspective view of the distal
end of tool attached to a spinal implant (FIG. 7B).
[0018] FIGS. 8A, 8B and 8C show a perspective view (FIG. 8A), a top
view (FIG. 8B) and an inner side view (FIG. 8C) of a spinal
implant.
DETAILED DESCRIPTION OF THE INVENTION
[0019] FIG. 1 shows the spinal implant 100 releasably attached to
an insertion instrument 200. The implant 100 may be made by made of
PEEK plastic commonly used in spinal implants. The implant includes
a hemispherical mount 105 and slanted cam surface 106 from which
the mount protrudes. The tip of rod 201 pivotably attaches to the
mount such that the implant may pivot with respect to the axis of
the instrument. The pivoting of the implant is controlled by the
knob on the instrument that rotates the cam wings 205 about the
hemispherical surface. The rotation of the cam, slides the front
edges of the cam wings across the cam surface 106 and thereby
forces the implant to pivot with respect to the axis of the
instrument.
[0020] A knob (e.g. actuator wings) 206 on the on the proximal end
of the instrument enables a surgeon to rotate the cam and thereby
adjust the angle between the implant and the axis of the
instrument. Pivoting of the implant is caused as the actuator
pushers 205 (e.g., cam) act on the slanted surface 106 of the
implant 100. As the cammed actuator 202 rotate and slide across the
slanted surface 106, the implant makes a yaw movement with respect
to the axis of the instrument. Actuator 202 is equipped with the
actuator wings 206 used to rotate pushers 205 (cam) from outside of
the patient's body.
[0021] Locking knob 207 may be tightened to bind the actuator
against the implant effectively locking the implant with respect to
the instrument. When locked, axial force and torque can be applied
to the handle 204 to advance the implant into the spinal space and
position the implant in the space. Turning the locking knob 207
that is threaded inside and engages threads on the proximal end of
the rod causes the actuator 202 that is hollow to slide axially
forward over the threaded rod 201 and thereby loosen or tighten the
actuator against the implant.
[0022] FIG. 2 shows the details of the attachment of the implant
100 to the instrument 200. Threaded pin 102 is inserted into the
channel 107 in the spherical protrusion (mount) 105 and retained
there by a snap ring 103. A threaded hollow shaft 108 in the
threaded pin 102 is aligned with the slot opening 109 of the
implant so that the treaded rod 201 can be threaded into the shaft
108 of the pin 102. Slot opening allows pivoting of the implant by
accommodating the pendulum motion of the rod 201. Pin 104 is made
of a material that enhances X-ray imaging. Making the pin visible
assists the physician in the positioning of the implant while
viewing a real-time x-ray image of the implant and vertebra.
[0023] The actuator 202 may be a hollow tube that is coaxial with
the rod 201. The pushers are fixed to the distal end of the
actuator. The pushers 205 include cams that engage a cam surface
106 on the implant. The proximal end of the tube has a knob (e.g.
actuator wings) 206 to turn the tube and thereby move the cams
against the cam surface. The angle of the implant with respect to
the actuator is adjusted by moving the cam against the cam surface.
Adjusting the angle may allow the surgeon to properly place the
implant in the spine area.
[0024] FIG. 3 illustrates the interaction between the Actuator 202
of the instrument and the implant 100. The actuator 202 is rotated
around the axis of the threaded rod 201 that is engaged in the
threaded pin 102. As the cammed pushers 205 rotate, they push
against the surface 106. As a result the implant 100 turns around
the axis of the pin 102. It can be envisioned as if the implant is
performing a "dog wagging its tail" motion with respect to the
insert instrument 200.
[0025] If the locking knob 207 (FIG. 1) is rotated, the actuator
202 is pushed against the implant 100. Both pushers are advanced
towards the surface 106 to bind the actuator against the implant so
as to lock the implant with respect to the instrument. When locked,
the assembly of the implant and instrument can be advanced while
retaining the desired angle of the implant 100 in relation to the
insertion instrument 200.
[0026] FIG. 4 shows the implant 100 with the insertion instrument
200 attached and in position on a patient vertebra 401. Rotation of
the actuator 202 in relation to the axis of the threaded rod 201
results in the rotation of the implant 100 around the axis of the
pin 102. Rotation of the knob 207 pushes the actuator 202 into the
implant locking the assembly. When the assembly is locked hammer
tapping can be applied to the handle 204 to advance the assembly
forward.
[0027] FIGS. 5A, 5B, 5C, 5D and 5E show a side view of a first
alternative spinal implant tool 500 to insert a spinal implant 502.
The tool has a handle 504 at a proximal end, a center rod that
connects to a pin or other attachment to the spinal implant, such
as rod 201 and pin 102 shown in FIG. 2, and a hollow rod 506 that
serves as an actuator rod similar to rod 201 in FIGS. 1 to 3. The
center rod may be turned from the handle by a turn knob 508 to
rotate the spinal implant about the axis of the rod. The actuator
rod 506 may be turned at the handle by a winged grip 510 to rotate
the cam surface 512 at the distal end of the actuator rod. Rotating
the actuator and cam surface causes the pivot yaw in a pivoting
movement illustrated in FIG. 3.
[0028] The cam surface 512 is a flat annular surface on a
cylindrical metal section 514 attached to the distal end of the rod
506. The cam surface 512 is in a plane offset from a plan
perpendicular to the axis of the rod. The degrees of the offset may
vary depending on the amount of yaw movement desired by the spinal
implant, but is preferably in a range of 5 degrees to 25 degrees.
The cam surface 512 abuts bull-nose surfaces 516 at the end of a
ridge 518 at the end of the spinal implant 502. The bull-nose
surfaces 518 may be on opposite sides of a hemispherical attachment
structure 519 that receives the end of the center rod and
releasable pin that temporarily secures the implant to the
tool.
[0029] The bull-nose surfaces slide against the cam surface 512 as
that surface and its rod rotate with respect to the inner rod that
is attached to implant. As the bull-nose surfaces slide against the
cam surface, the spinal implant moves in a yaw direction. The yaw
movement of the implant is controlled by the surgeon twisting the
winged grip 510 at the handle. To assist the surgeon in determining
the yaw orientation of the implant, a shallow groove 520 may be
machined in the cam surface. The surgeon will feel in his fingers
in the winged grip the action of the bull nose surfaces sliding
across the groove. Knowing when the spinal implant is in the yaw
orientation corresponding to the grooves 520 gives the surgeon
information helpful in positioning the spinal implant in the spine.
Further, the grooves 512 may be used to lock the yaw position of
the spinal implant by applying sufficient compressive force between
the bull nose surfaces and cam surface. The compressive force may
be adjusted by turning the rod so that its threaded end turns into
or out of the pin in the hemispherical structure 519.
[0030] FIGS. 6A, 6B and 6C show views of second alternative spinal
implant tool 600 having many components similar to the tool 500
shown in FIG. 5A. These similar components are labeled with the
same reference numbers as used in FIG. 5A and the corresponding
text description of the tool given for FIG. 5A applies to tool 600.
The distal end of the actuator rod 602 includes a gear actuator 604
that engages gear teeth on a semi-circular gear attachment 606 on
the spine implant 608. The gear actuator 604 make by half-circle
gear extending partially, e.g., half-way, around the axis 610 of
the rod 602. The engagement of the teeth of the gear 604 with the
teeth of the attachment 606 on the implant 608 causes the implant
to pivot about pin 612 coupled to a hemispherical attachment 614
(similar to hemispherical attachment 519) and engaging a threaded
end of the center rod 616 of the tool. The gear attachment 606 is
on the end of the implant and offset from the hemispherical
attachment 614.
[0031] Due to the engagement between the gear teeth of the gear
attachment 606 on the implant and the gear actuator 604 on the
actuator, the surgeon can turn the wing grip 510 on the actuator
rod to cause the implant to yaw back and forth respect to the axis
610 of the tool 600. Turing the actuator rod approximately 180
degrees causes the gear teeth on the gear attachment 606 to
disengage and rotate away from the gear actuator 604. Further, yaw
movement of the implant can be prevent by turning locking knob 510
that the geared actuator 604 is forced into the gears of the geared
to bind against the gear teeth in the gear attachment creating
sufficient friction to prevent implant rotation in the yaw
directions.
[0032] FIGS. 7A and 7B show a third alternative spinal implant tool
700 having many components similar to the tool 500 shown in FIG.
5A. These similar components are labeled with the same reference
numbers as used in FIG. 5A and the corresponding text description
of the tool given for FIG. 5A applies to tool 600. The center rod
702 may have a threaded end that engages a pin 704 mounted in a
hemispherical attachment 708 (similar to hemispherical attachment
519) at the end of the spinal implant 706. The end of the implant
with the hemispherical attachment has a slanted surface 710. The
distal end of the actuator rod 712 includes a pair of legs 714 each
having a bull-nose end surface 716 that slides against the slanted
surface at the end of the spinal implant. The rotation of the wing
grip 510 at the handle end 504 of the tool 700 turns the actuator
shaft 712 and causes the bull-nose end surfaces 716 to slide
against the slanted surface 708 of the implant. The sliding
movement of the bull-nose end surface against the surface 708
pivots the implant in a yaw movement with respect to the axis of
the tool.
[0033] The spinal insertion tool may be used to prepare a space for
an implant between adjacent vertebra. The tool 700 provides a
steerable tool having detachable tips. These tips may include, but
not limited to, interchangeable rasps, curettes, broaches,
osteotomes, reamers, dissectors and implant trial sizes. The
interchangeable instrument tips are steered and released by any
method or combination of methods described above.
[0034] The slanted surface 710 may be included in a wedge
attachment 718 attached by a bracket 720 on the end of the implant
706. The wedge attachment may be secured to the implant prior to
surgery and before the implant is inserted into the spine of a
patient. The wedge attachment may be interchangeable with other
attachments to the spinal implant, such as wedges with slanted
surfaces of varying angles to provide variable sweep of the yaw
movement. In addition, the wedge attachment may be used secured to
surgical rasps, curettes, spoons, picks, scrapers and other
surgical tools. The wedge attachment allows a variety of surgical
tools to be mounted on the end of the spinal implant tool which,
with these tools, can perform surgical functions, e.g., removing
bone, spinal disc and other material from a disc region of the
spine, smoothing a spine surface to later receive a spinal implant
and to clear away material from the disc region. Accordingly, the
spinal tool may be used for surgical procedures in addition to
implanting a spinal insert and steering the insert during its
insertion into the spine.
[0035] A spinal implant may be used to stabilize a portion of a
spine. The implant may promote bone growth between adjacent
vertebra that fuses the vertebra together. An implant may include
an opening through a height of a body of the implant. The body of
the implant may include curved sides. A top and/or a bottom of the
implant may include protrusions that contact and/or engage
vertebral surfaces to prevent backout of the implant from the disc
space.
[0036] A spinal implant may be used to provide stability and
promote fusion of adjacent vertebra. The implant may be used in
conjunction with a spinal stabilization device such as a bone plate
or rod-and-fastener stabilization system. The implant may establish
a desired separation distance between vertebra. The implant may
promote bone growth between adjacent vertebra that fuses the
vertebra together. Instrument at is necessary for insertion of an
implant in a patient and alignment of the implant in the space.
[0037] A discectomy may be performed to establish a disc space
between vertebra. The disc space may be prepared for implant
insertion by distraction of adjacent vertebra, rasping and filing
of the bone to achieve the desired spacing. It is desired to
perform insertion of the implant and positioning of the implant
using minimum number of inserted instruments and thought the
smallest possible insertion channel in the body.
[0038] Implants may be constructed of biocompatible materials
sufficiently strong to maintain spinal distraction. Implants may
include, but are not limited to, allograft bone, xenograft bone,
autograft bone, metals, ceramics, inorganic compositions, polymers
such as PEEK, or combinations thereof. If the implant is not made
of bone, surfaces of the implant that contact bone may be treated
to promote fusion of the implant to the bone. Treatment may
include, but is not limited to, applying a hydroxyapatite coating
on contact surfaces, spraying a titanium plasma on contact
surfaces, and/or texturing the contact surfaces by scoring,
peening, implanting particles in the surfaces, or otherwise
roughening the surfaces.
[0039] FIGS. 8A, 8B and 8C show a perspective view (FIG. 8A), a
tope view (FIG. 8B) and an inner side view (FIG. 8C) of a spinal
implant 800 formed of a polymer (PEEK) implant body and including
of a metallic ball 802. The ball may be formed of titanium and
inserted in a hemispherical recess 804 of the end 806 of the
implant 800. For example, the end section 806 of the implant may be
a wedge having an inner chamber to receive and hold the ball 802.
The wedge 806 is secured to an end surface 808 of the body 810 of
the implant. The wedge, when secured to the body, holds the ball
802 on the implant and allows the ball to pivot with the threaded
end of the spinal implant tool. The ball may be hollow and have a
cylindrical aperture 812 to receive a pin. The pin (see FIG. 2) has
a threaded side aperture to receive a threaded end of the centre
rod of a spine insertion tool. The ball 802, and preferably the
wedge 806, are formed of a metal (such as Titanium) for strength.
The body 810 of the implant may be formed of an alternate material,
such as a radiolucent polymer (including, but not limited to,
PEEK).
[0040] In some embodiments, an implant may include an opening that
extends through a body of the implant. The opening may have a
regular shape or an irregular shape. Bone graft may be placed in
the opening. The bone graft may be autogenic bone graft, allogenic
bone graft, xenogenic bone graft, and/or synthetic bone graft. Some
implant embodiments may be constructed from allogenic bone, such as
cortical bone from a femur, tibia, or other large bone. In some
embodiments, an implant may be formed from one or more pieces of
allograft bone cut to a desired shape.
[0041] In certain embodiments, sides of an implant may be shaped to
increase contact between an implant and adjacent vertebra with
notches, ribs and other similar features. Increasing contact of an
implant with adjacent vertebra may inhibit movement of the implant
after insertion. An increased contact area between an implant and
adjacent vertebra may promote bone growth between adjacent
vertebra.
[0042] In some embodiments, one or more sides of an implant may be
curved. One or more curved sides of an implant may allow the
implant to be maneuvered in a disc space during insertion of the
implant. The curvature of a side may approximate a curvature of an
anterior side of a vertebra adjacent to which the implant is
inserted.
[0043] Instruments may be used to prepare a space for an implant
between adjacent vertebra. FIG. 7 shows views of an instrument with
steerable and detachable tips, including, but not limited to,
interchangeable rasps, curettes, broaches, osteotomes, reamers,
dissectors and implant trial sizes. The interchangeable instrument
tips are steered and released by any method or combination of
methods described in the paragraphs and figures above. An
instrument may be used to insert an implant in a prepared space.
Instruments may be supplied to a surgeon or surgical team in an
instrument set. An instrument set may include one or more implants
for use during an insertion procedure. An instrument set may
include implants of various sizes and/or lordotic angles to allow
selection of an implant to suit a patient during surgery.
Instrument is attached to the implant before the insertion into the
body. When the desired position of the implant is achieved,
instrument is disengaged from the implant and can be extracted from
the body.
[0044] An instrument acts as an implant inserter. The implant
inserter may be used to push the implant and to rotate the implant.
After insertion of the implant, the implant may be released from
the inserter without the application of significant repositioning
forces to the implant. It can be imagined that the insertion
instrument can be screwed into the implant using threads or use
other techniques such as a tightening collet, jamming or grabbing.
In the disclosed embodiment the implant turns around the axis of
the implant pin as a result of the rotation of cam pushers. It can
be imagined that other mechanisms can be used to rotate the implant
such as ratchets or threaded push rods. The implant inserter may
have a low profile that allows for visualization of the implant and
surrounding area during insertion of the implant. Implant is
equipped to couple and uncouple from the instrument.
[0045] While the invention has been described in connection with
what is presently considered to be the most practical and preferred
embodiment, it is to be understood that the invention is not to be
limited to the disclosed embodiment, but on the contrary, is
intended to cover various modifications and equivalent arrangements
included within the spirit and scope of the appended claims.
* * * * *