U.S. patent application number 17/031090 was filed with the patent office on 2021-03-25 for interbody spacer for spinal fusion.
The applicant listed for this patent is CoreLink, LLC. Invention is credited to Josh Arnone, Ph.D., Adam MacMillan.
Application Number | 20210085483 17/031090 |
Document ID | / |
Family ID | 1000005130617 |
Filed Date | 2021-03-25 |
View All Diagrams
United States Patent
Application |
20210085483 |
Kind Code |
A1 |
MacMillan; Adam ; et
al. |
March 25, 2021 |
INTERBODY SPACER FOR SPINAL FUSION
Abstract
An interbody spacer for spinal fusion surgery includes a body
configured for insertion within an interbody space between two
adjacent vertebrae. The body defines at least one
fastener-receiving opening for receiving a fastener for securing
the body within the interbody space. A blocking member is
disposable in the fastener-receiving opening for preventing the
fastener from being withdrawn from the fastener-receiving opening
once the fastener has been fully inserted into the
fastener-receiving opening.
Inventors: |
MacMillan; Adam; (Fenton,
MO) ; Arnone, Ph.D.; Josh; (St. Louis, MO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CoreLink, LLC |
St. Louis |
MO |
US |
|
|
Family ID: |
1000005130617 |
Appl. No.: |
17/031090 |
Filed: |
September 24, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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62905123 |
Sep 24, 2019 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2/442 20130101;
A61F 2/3094 20130101; A61F 2/4611 20130101; A61F 2002/30985
20130101; A61F 2/4455 20130101 |
International
Class: |
A61F 2/44 20060101
A61F002/44; A61F 2/30 20060101 A61F002/30; A61F 2/46 20060101
A61F002/46 |
Claims
1. An interbody spacer for spinal fusion surgery, the interbody
spacer comprising: a body configured for insertion within an
interbody space between two adjacent vertebrae, the body defining
at least one fastener-receiving opening for receiving a fastener
for securing the body within the interbody space; and a blocking
member disposable in the fastener-receiving opening for preventing
the fastener from being withdrawn from the fastener-receiving
opening once the fastener has been fully inserted into the
fastener-receiving opening.
2. The interbody spacer set forth in claim 1, wherein the blocking
member comprise a tab extending into the fastener-receiving
opening.
3. The interbody spacer set forth in claim 2, wherein the tab is
configured to deflect away from the fastener-receiving opening to
allow the fastener to be inserted into the fastener-receiving
opening and to flex back toward the fastener-receiving opening to
block the fastener from being withdrawn from the fastener-receiving
opening.
4. The interbody spacer set forth in claim 1, wherein the body
defines a second opening, the blocking member being received in the
second opening and movable within the second opening to dispose at
least a portion of the blocking member in the fastener-receiving
opening.
5. The interbody spacer set forth in claim 4, wherein the
fastener-receiving opening comprises a first fastener-receiving
opening, the body further defines a second fastener-receiving
opening for receiving a fastener for securing the body within the
interbody space, the blocking member being disposable in both the
first and second fastener-receiving openings.
6. The interbody spacer set forth in claim 4, wherein the body
includes detents engagable with the blocking member to lock the
blocking member in position whereby said at least a portion of the
blocking member is disposed in the fastener-receiving opening.
7. The interbody spacer set forth in claim 4, wherein the blocking
member defines a tool-receiving receptacle for receiving a tool to
move the blocking member in second opening.
8. The interbody spacer set forth in claim 1, wherein the body
includes first and second opposite side walls, and front and rear
walls extending between and interconnecting the first and second
side walls, interior surfaces of the front and rear walls and
interior surfaces of the first and second side walls defining an
interior cavity in the body, the at least one fastener-receiving
opening being formed in the front wall and defining an opening
axis, the opening axis extending at an angle to a horizontal
plane.
9. The interbody spacer set forth in claim 8, wherein the at least
one fastener-receiving opening comprises a first fastener-receiving
opening defining a first opening axis, a second fastener-receiving
opening being formed in the front wall and defining a second
opening axis, the second opening axis extending at an angle to the
horizontal plane.
10. The interbody spacer set forth in claim 1, wherein the
fastener-receiving opening defines a notch for receiving a rib on
the fastener for preventing the fastener from rotating relative to
the spacer.
11. A method of making an interbody spacer for spinal fusion
surgery, the method comprising 3D printing the interbody spacer,
wherein the interbody spacer comprises a body and a blocking member
movable relative to the body.
12. The method set forth in claim 11, wherein the body and blocking
member are integrally formed.
13. The method set forth in claim 11, wherein 3D printing the
interbody spacer comprises printing a gap between the spacer body
and the blocking member to permit the blocking member to move
relative to the spacer body, unmelted powder stock material being
disposed in the gap between the spacer body and the blocking
member.
14. A fastener for use in an interbody spacer for spinal fusion
surgery, the fastener comprising: a base defining a receptacle for
receiving a driver for driving the fastener into a bony structure;
a shaft extending from the base along an arc; and a tip portion
extending from the shaft and including a pointed end for taping
into the bony structure.
15. The fastener set forth in claim 14, wherein the shaft comprises
spirally extending teeth arranged in a helical pattern.
16. The fastener set forth in claim 15, wherein the shaft defines a
plurality of holes spaced along the shaft.
17. The fastener set forth in claim 14, further comprising bone
growth material disposed on the shaft.
18. The fastener set forth in claim 14, wherein the receptacle is
free of threads.
19. The fastener set forth in claim 18, wherein the receptacle
includes a rounded interior surface.
20. The fastener set forth in claim 14, further comprising a rib
formed on the base.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to U.S. Provisional Patent
Application Ser. No. 62/905,123, filed Sep. 24, 2019, which is
hereby incorporated by reference in its entirety.
FIELD OF THE DISCLOSURE
[0002] The present disclosure generally relates to an interbody
spacer for spinal fusion.
BACKGROUND OF THE DISCLOSURE
[0003] Spinal fusion is a surgical procedure used to correct
problems with vertebrae of the spine. Spinal fusion fuses together
the painful vertebrae so that they heal into a single, solid bone.
In one method, the intervertebral disc between two vertebrae is
removed and a small interbody spacer, also known as a cage, is
inserted between the vertebrae. These interbody spacers usually
contain bone graft material to promote bone healing and facilitate
the fusion. After the interbody spacer is inserted, surgeons often
use metal screws, plates, and rods to further stabilize the
spine.
SUMMARY
[0004] In one aspect, an interbody spacer for spinal fusion surgery
generally comprises a body configured for insertion within an
interbody space between two adjacent vertebrae. The body defines at
least one fastener-receiving opening for receiving a fastener for
securing the body within the interbody space. A blocking member is
disposable in the fastener-receiving opening for preventing the
fastener from being withdrawn from the fastener-receiving opening
once the fastener has been fully inserted into the
fastener-receiving opening.
[0005] In another aspect, a method of making an interbody spacer
for spinal fusion surgery generally comprises 3D printing the
interbody spacer. The interbody spacer comprising a body and a
blocking member movable relative to the body.
[0006] In yet another aspect, a fastener for use in an interbody
spacer for spinal fusion surgery generally comprises a base
defining a receptacle for receiving a driver for driving the
fastener into a bony structure. A shaft extends from the base along
an arc. A tip portion extends from the shaft and includes a pointed
end for taping into the bony structure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a perspective of one embodiment of an interbody
spacer assembly constructed according to the teachings of the
present disclosure;
[0008] FIG. 2A is a perspective of an interbody spacer of the
interbody spacer assembly;
[0009] FIG. 2B is a top plan view of the interbody spacer;
[0010] FIG. 3 is a perspective of a fastener of the interbody
spacer assembly;
[0011] FIG. 4 is another perspective of the fastener;
[0012] FIG. 5 is a perspective of another fastener;
[0013] FIG. 6 is another perspective of the fastener of FIG. 5;
[0014] FIGS. 7A-7D are illustrations of fasteners being inserted
into the interbody spacer;
[0015] FIG. 8 is a perspective of the interbody spacer with another
embodiment of fasteners;
[0016] FIG. 9A is a front perspective of another embodiment of an
interbody spacer assembly constructed according to the teachings of
the present disclosure and showing a blocking member in a locked
configuration;
[0017] FIG. 9B is a fragmentary rear perspective of the assembly of
FIG. 9A;
[0018] FIG. 10A is a front perspective of the interbody spacer
assembly of FIG. 9A showing the blocking member in an unlocked
configuration;
[0019] FIG. 10B is a fragmentary rear perspective of the assembly
of FIG. 10A;
[0020] FIG. 11 is a top plan view of an interbody spacer of the
assembly of FIG. 9A;
[0021] FIG. 12 is a section of the interbody spacer of FIG. 11;
[0022] FIG. 13 is another section of the interbody spacer of FIG.
11;
[0023] FIG. 14 is a perspective of the interbody spacer assembly of
FIG. 9A with a different embodiment of fasteners;
[0024] FIG. 15 is a front perspective of another embodiment of an
interbody spacer assembly constructed according to the teachings of
the present disclosure;
[0025] FIG. 16A is a side view of another fastener;
[0026] FIG. 16B is an end view of the fastener of FIG. 16A;
[0027] FIG. 16C is a section of the fastener of FIG. 16A;
[0028] FIG. 17A is a fragmentary perspective of a driver;
[0029] FIG. 17B is a front view of the driver of FIG. 17A;
[0030] FIG. 17C is a top view of the driver of FIG. 17A;
[0031] FIG. 18A-18C are illustrations of the driver being received
in a base of the fastener of FIG. 16A;
[0032] FIGS. 19A-19G are illustrations of the fastener of FIG. 16A
being inserted into a spacer of the spacer assembly of FIG. 15;
[0033] FIG. 20 is another front perspective of the interbody spacer
assembly of FIG. 15; and
[0034] FIG. 21 is front perspective of the interbody spacer of the
interbody spacer assembly of FIG. 15.
[0035] Corresponding reference characters indicate corresponding
parts throughout the drawings.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0036] Referring to FIGS. 1-2B of the drawings, a first embodiment
of an interbody spacer assembly is generally indicated at reference
numeral 1. The interbody spacer assembly 1 comprises an interbody
spacer 10 and fasteners 11 for securing the spacer to one or more
adjacent bony structures. The interbody spacer 10 is designed for
use in lumbar interbody fusion surgery. The spacer 10 includes
opposite first and second side walls generally indicated at 12, 14;
opposing front and rear walls, generally indicated at 16 and 18,
respectively, and extending between the first and second side walls
and defining a transverse dimension (e.g., width) of the interbody
spacer therebetween; and opposite upper and lower faces, generally
indicated at 20, 22, defining a height of the interbody spacer
therebetween. A horizontal plane P extends through the first and
second side walls 12, 14 and the opposing front and rear walls 16,
18. Interior surfaces of the front and rear walls 16, 18 and the
first and second side walls 12, 14 define an interior cavity 24.
The upper and lower faces 20, 22 extend only partially across the
upper and lower margins of the interbody spacer 10 defining
openings at the top and bottom of the interbody spacer. Thus, the
interior cavity 24 is open at upper and lower margins of the
interbody spacer 10. The interior cavity, or "graft window," 24 is
configured to receive bone graft material (not shown) to facilitate
bone growth. In one embodiment, the graft window 24 is lined with
an open-cell metal foam 26 (also referred to as a randomized
"trabecular lattice" and may be comprised of titanium or other
metal). The trabecular lattice 26 may extend along the entire
heights and widths of the interior surfaces of the side walls 12,
14 and the front and rear walls 16, 18 (i.e., the lattice covers
entireties of the interior surfaces of the side walls and front and
rear walls). As used herein, terms such as "inner," "outer,"
"inward," "outward," "exterior," and "interior," relate to
locations relative to the interior cavity, and the terms such as
"front," "rear," "upper" and "lower" refer to the orientation of
the spacer when positioned in the body.
[0037] The first and second side walls 12, 14 and the front and
rear walls 16, 18 comprise generally solid bodies (e.g., titanium
or other metal or other material) to enhance the structurally
integrity (e.g., compressive strength) of the spacer 10. The front
wall 16 defines a centrally located tool-receiving opening 27 and a
pair of fastener-receiving openings 28 disposed on opposite sides
of the tool-receiving opening. The openings 27, 28 extend through
the front wall 16 to the interior cavity 24. The tool-receiving
opening 27, which may be threaded as illustrated, is configured to
receive a suitable insertion tool for use in inserting the
interbody spacer 10 in the patient. The tool-receiving opening 27
defines an opening axis A1 that extends generally parallel to the
horizontal plane P of the spacer 10. The interbody spacer 10 may
include other features for use with a suitable insertion tool. The
fastener-receiving openings 28 define opening axes A2, A3 that
extend at an angle to the horizontal plane P of the spacer 10. In
the illustrated embodiment, axis A2 of a first fastener-receiving
opening 28 is angled downward such that the axis extends through a
bottom opening of the interior cavity 24, and axis A3 of a second
fastener-receiving opening 28 is angled upward such that the axis
extends through a top opening of the interior cavity. The
fastener-receiving openings 28 are configured to receive a suitable
fastener (such as fasteners 11) for use in securing the interbody
spacer 10 in the patient. As will be described in greater detail
below, fasteners 11 comprise curved nails/blades. However, any
suitable fastener may be used. For example, a traditional bone
screw 33 (FIG. 8) may also be used. Additionally, any combination
of fasteners can be used without departing from the scope of
disclosure. For example, a nail 11 could be inserted into the first
fastener-receiving opening 28 (i.e., the left fastener opening in
FIG. 1) and a bone screw 33 could be inserted in the second
fastener-receiving opening 28 (i.e., the right fastener opening in
FIG. 1). In this embodiment, the nail 11 would extend downward and
the screw 33 would extend upward. Alternatively, the screw 33 could
be inserted into the first fastener-receiving opening 28 and the
nail 11 could be inserted in the second fastener-receiving opening
28.
[0038] Locking tabs 40 are formed in the fastener openings 28 and
are configured to engage the fasteners 11 to prevent the fasteners
from being pushed or pulled back out of the openings once the
fasteners have been fully inserted into the openings. In the
illustrated embodiment, each tab 40 is formed from the body of the
spacer 10 and comprises a piece of material angled away from the
material surrounding the fastener-receiving opening 28. Thus, the
tabs 40 extend from the adjacent surrounding material and into the
fastener-receiving openings 28. The tabs 40 are positioned within
the openings 28 such that a base 60 of the fastener 11 will engage
the tab as the fastener is being inserted into the opening and
deflect the tab away from the opening 28 to allow for passage of
the fastener. The tab 40 will then flex back to its pre-engaged
position once the base 60 of the fastener 11 clears the tab thereby
extending over the base of the fastener preventing the fastener
from being withdrawn from the opening 28. The locking tab 40 may be
broadly considered a blocking member such that the locking tab
blocks the fastener 11 from being withdrawn from the
fastener-receiving opening 28.
[0039] The material surrounding the fastener-receiving openings 28
also defines a fastener engagement portion 44 configured to seat
the base 60 of the fastener 11 in the fastener-receiving opening
once the fastener has been fully inserted into the opening. The
fastener engagement portion 44 comprises a first angled section 46,
a second angled section 48 extending at an angle from the first
angled section, and a third angled section 50 extending at an angle
from the second angled section. The third angled section 50 extends
inward from the second angled section 48 to form a reduced diameter
section of the fastener-receiving opening 28 which prevents the
fastener 11 from being inserted entirely through and out of the
bottom of the opening, as will be explained in greater detail
below.
[0040] The upper and lower faces 20, 22 include rows of teeth 34.
In the illustrated embodiment, there are two rows of teeth 34. Each
row of teeth 34 extends between the front and rear walls 16, 18 and
is located adjacent a respective side wall 12, 14. Thus, the first
and second side walls 12, 14 are serrated at the upper and lower
edge margins of the walls. The rows of teeth 34 facilitate
anchoring of the interbody spacer 10 to the adjacent vertebrae
within the interbody space to inhibit movement of the interbody
spacer within the space. In other embodiments, the interbody spacer
10 may include other features to facilitate anchoring and inhibit
movement of the interbody spacer within interbody space.
[0041] As shown in FIG. 1, each side wall 12, 14 further includes a
three-dimensional lattice (i.e., 3D lattice), generally indicated
at 52, disposed heightwise between the upper and lower surfaces 20,
22 and disposed widthwise between the front and rear walls 16, 18
(only the lattice on side wall 12 is shown). Solid frames 54
surround outer portions of the 3D lattices 52. Each 3D lattice 52
defines a plurality of intersecting passages extending
therethrough. In this way, bone growth from vertebrae can enter the
3D lattice 52 and grow within the interconnected passages of the 3D
lattice.
[0042] The interbody spacer 10 may be integrally formed as a
one-piece monolithic component. For example, the entirety of the
interbody spacer 10 may be formed by additive manufacturing, such
as by direct metal laser sintering or by electron beam melting
processes, as is generally known. The interbody spacer 10 may be
formed entirely from a single type of metal, such as titanium, or
the interbody spacer may comprise more than one type of metal. The
interbody spacer 10 may also be formed in other ways. For example,
the entirety of the interbody spacer 10 may be formed from 3D
printing. During the 3D printing process, the interbody spacer 10
may be printed from the bottom of the spacer up to the top of the
spacer, and from the back of the spacer to the front of the spacer.
In the illustrated embodiment, the front wall 16 defines a front of
the spacer 10.
[0043] Referring to FIGS. 3 and 4, the fasteners 11 comprise curved
trabecular nails/blades configured for insertion into a subject's
bony structures (e.g., vertebrae). The nails 11 include a base 60,
a shaft 62 extending from the base, and a tip portion 64 extending
from the shaft. An inner surface of the base 60 defines a
receptacle 66 for receiving a driver (not shown) for driving the
nail into the bony structure. An outer circumferentially extending
surface of the base 60 defines a unique contour for seating the
base of the nail 11 in the fastener-receiving openings 28 of the
spacer 10. In particular, the outer surface of the base 60
comprises a first angled section 68 extending from a rim 70 of the
base, a second angled section 72 extending at an angle from the
first angled section, and a third angled section 74 extending at an
angle from the second angled section. The third angled section 74
of the base 60 is sized to engage the third angled section 50 of
the fastener engagement portion 44 extending around the
fastener-receiving openings 28 to seat the nail 11 in the opening.
The shaft 62 comprises spirally extending teeth 76 that extend from
the base 60 to the tip portion 64. In the illustrated embodiment,
there are two rows of teeth 76. However, the shaft 62 could include
additional rows of teeth without departing from the scope of the
disclosure. Trabecular lattice 26 is disposed around the teeth 76
and similarly extends from the base 60 to the tip portion 64. At
least a portion of each tooth 76 protrudes from the lattice 26 so
that the teeth can be used to anchor the nail 11 in the bony
structure. In particular, each tooth 76 included a forward cutting
surface 78 for penetrating the bony structure, and a reward
anti-retraction surface 80 for holding the nail 11 in the bony
structure. The spiral arrangement of the teeth 76 also enhances the
pullout strength of the nail 11. However, the nail could be
straight without departing from the scope of the disclosure. The
tip portion 64 comprises a smooth outer surface that tapers to a
pointed end for piercing the bony structure. It is also envisioned
that the nails 11 could have other configurations without departing
from the scope of the disclosure. For example, the nails could have
a similar configuration but with the trabecular lattice removed.
This embodiment is shown as fastener 11' in FIGS. 5 and 6. Fastener
11' is identical to fastener 11 except for that the removal of the
bone growth material exposes a helical shaft 62'. The helical shaft
defines the two rows of spirally extending teeth 76' as well as a
central row of holes 77'. This helical shaft also enhances the
flexural strength of the nail in all directions (i.e. increased
isotropy) as compared to a "non-twisted" configuration. The holes
maximize internal porosity thereby providing additional areas for
bone growth. The fastener 11' is otherwise constructed identically
to fastener 11.
[0044] Referring to FIGS. 7A-D, in use, the interior cavity 24 may
be packed with bone graft material and then inserted with an
insertion tool within an interbody space between two adjacent
vertebrae in a suitable surgical procedure such that the upper face
20 of the spacer 10 contacts the upper or superior vertebra and the
lower face 22 of the spacer contacts the lower or inferior
vertebra. In this position, the upper and lower teeth 34 anchor
into the respective superior and inferior vertebrae. Next, the
fasteners 11 can be inserted into the fastener-receiving openings
28 to anchor the spacer 10 to the superior and inferior vertebra.
Fully inserting the fasteners 11 such that the base 60 of the
fastener is seated on the fastener engagement portion 44
surrounding the fastener-receiving openings 28 will cause the
locking tabs 40 to lock the fasteners in the openings preventing
the fasteners from being withdrawn. After insertion of the spacer
10 and completion of the surgery, it is envisioned that bone from
the adjacent vertebrae will grow into the trabecular lattice 26 in
the interior cavity 24 and the 3D lattices 52 on the spacer. It is
believed such bone growth into the interbody spacer 10 by way of
the trabecular lattice 26 and the 3D lattices 52 promotes bone
growth of the vertebrae and enhances fusion of the patient's spine,
as is desired in such fusion surgery.
[0045] Referring to FIG. 9A-14, another embodiment of an interbody
spacer assembly is generally indicated at reference numeral 101.
The interbody spacer assembly 101 comprises an interbody spacer 110
and fasteners (i.e., bone screws) 33 for securing the spacer to one
or more adjacent bony structures. This interbody spacer 110 is
designed for use in lumbar interbody fusion surgery. This interbody
spacer 110 is similar structurally to the interbody spacer 10. As
such, the spacer 110 has essentially the same structural elements
as spacer 10, which are indicated by corresponding reference
numerals plus 100. Differences between interbody spacer 110 and
interbody spacer 10 are discussed below.
[0046] One difference between interbody spacer 110 and interbody
spacer 10 is that the tool-receiving opening 27 of spacer 10 is
replaced with a blocking member opening 127 for receiving a
blocking member 182 to block the fasteners 33 from being withdrawn
from the fastener-receiving openings 128. Thus, the locking tabs 40
of spacer 10 are omitted from this embodiment and replaced with the
blocking member 182. The blocking member opening 127 is generally
positioned within the center of the spacer 110 between first and
second side walls 112, 114. The blocking member opening 127 extends
from the front wall 116 to an interior cavity 124 of the spacer
110. The blocking member opening 127 includes a first portion 184
that extends from the front wall 116 toward the interior cavity
124, and a second portion 186 that extends from the first portion
to the interior cavity 124. The first portion 184 is defined by a
funneled or conical surface that forms a reduced diameter section
of the opening 127. The second portion 186 comprises a flared
surface that extends from the funneled surface and widens the
blocking member opening 127. A detent mechanism 188 is formed on an
inner surface of the spacer 110 defining the interior cavity 124.
The detent mechanism 188 comprises a pair of detents 190 including
a ramp surface and a catch surface. The detents 190 are configured
to engage the blocking member 182 to lock the blocking member in a
locked position, as will be explained in greater detail below.
[0047] The blocking member 182 is configured to be received in the
blocking member opening 127 and rotate in the opening to
selectively place the blocking member in a locked (FIGS. 9A and 9B)
and unlocked (FIGS. 10A and 10B) position. The blocking member 182
comprises a head 192 and a shaft 194 extending from the head. The
head 192 has an elongate front face that has a generally Z or S
like shape defining protrusions 195 at the ends of the head. A
receptacle 196 is formed in the front face of the head 192 and is
configured to receive a tool (not shown) for rotating the blocking
member in the blocking member opening 127. A side surface 197 of
the head 192 extends downward from the top surface, and a bottom
surface 198 extends downward and tapers inward from the side
surface. The bottom surface 198 has a mating profile with the
funneled surface that defines the first portion 184 of the blocking
member opening 127 so that the bottom surface can engage the
funneled surface to seat the blocking member 182 in the blocking
member opening. The funneled surface also extends laterally outward
from the reduced diameter portion of the blocking member opening
127 thereby preventing the blocking member from falling out of the
bottom of the blocking member opening. The shaft 194 of the
blocking member generally flares outward as it extends away from
the head 192 thereby progressively increasing a lateral dimension
of the shaft. The lateral dimension of the shaft 194 increases such
that at least a portion of the shaft is larger than the diameter of
the reduced diameter portion of the blocking member opening 127.
Therefore, the shaft 194 prevents the blocking member 182 from
being pulled out of the top of the blocking member opening 127. A
pair of wings 199 are formed on the shaft 194 and extend laterally
outward from the shaft. The wings 199 are configured to engage the
detents 190 to lock the blocking member 182 in the locked position.
In one embodiment, the wings 199 provide a snap-fit engagement with
the detent mechanism 188.
[0048] The blocking member opening 127 communicates with the
fastener-receiving openings 128 such that rotation of the blocking
member 182 in the blocking member opening causes at least portions
of the head 192 to enter into the fastener-receiving openings. In
particular, the head 192 of the blocking member 182 can be rotated
to the unlocked position (FIGS. 10A and 10B) which clears the
protrusions 195 on the head from the fastener-receiving openings
128 permitting the fasteners 33 to be inserted into the
fastener-receiving openings. When the fasteners 33 are fully
inserted, the head 192 can be rotated to the locked position (FIGS.
9A and 9B) so that the protrusions 195 on the head extend over the
fastener-receiving openings 128 to block the fasteners from being
withdrawn from the openings. Rotation of the head 192 to the locked
position also causes the wings 199 on the shaft 194 to engage the
ramp surfaces of the detents 190 and snap past the catch surfaces
preventing the head from being rotated back to the unlocked
position. Thus, the blocking member 182 provides a similar locking
function to the locking tab 40 of spacer 10. Additionally, while
the spacer 110 is shown as being used with screws 33, the spacer
could be used with any suitable fastener such as nails 11 shown in
FIG. 14. Still other suitable fasteners such as nails 11' are also
envisioned.
[0049] The interbody spacer 110 may be integrally formed as a
one-piece monolithic component. For example, the entirety of the
interbody spacer 110 may be formed by additive manufacturing, such
as by direct metal laser sintering or by electron beam melting
processes, as is generally known. The interbody spacer 110 may be
formed entirely from a single type of metal, such as titanium, or
the interbody spacer may comprise more than one type of metal. The
interbody spacer 110 may also be formed in other ways. For example,
the entirety of the interbody spacer 110 may be formed from 3D
printing. During the 3D printing process, the interbody spacer 110
may be printed from the bottom of the spacer up to the top of the
spacer, and from the back of the spacer to the front of the spacer.
In the illustrated embodiment, the front wall 116 defines a front
of the spacer 10. The 3D printing process may be used to print the
body of the spacer 110 and the blocking member 182 in the same
printing session. For example, as the printer is printing the lines
that includes the body of the spacer 110 and the blocking member
182, the gap between the spacer body and the blocking member will
be filled with unmelted stock material in powder form that will
eventually be removed providing the clearance necessary for the
blocking member to move relative to the spacer body. Building from
the bottom of the spacer 110 up to the top and from the back to the
front facilitates 3D printing in this manner.
[0050] In use, the interbody spacer 110 may be implanted in the
patient in a suitable manner. It is believed the interbody spacer
110 promotes bone ingrowth in the same manner as described above
with respect to interbody spacer 10.
[0051] Referring to FIG. 15-21, another embodiment of an interbody
spacer assembly is generally indicated at reference numeral 201.
The interbody spacer assembly 201 comprises an interbody spacer 210
and fasteners 211 for securing the spacer to one or more adjacent
bony structures. This interbody spacer 210 is designed for use in
lumbar interbody fusion surgery. This interbody spacer 210 is
similar structurally to the interbody spacer 10. As such, the
spacer 210 has essentially the same structural elements as spacer
10, which are indicated by corresponding reference numerals plus
200. Also, the fasteners 211 are structurally similar to fasteners
11. As such, the fasteners 211 are indicated by corresponding
reference numerals plus 200. Differences between interbody spacer
210 and interbody spacer 10, and the differences between the
fasteners 211 and fasteners 11 are discussed below.
[0052] Referring to FIGS. 15 and 19A-21, one difference between
interbody spacer 210 and interbody spacer 10 comprises the
construction of locking tab 240. On interbody spacer 210, the
locking tabs 240 comprise a first arm 241 extending generally
longitudinally along an axis of the fastener-receiving opening 228,
and a second arm 243 extending transversely from the first arm and
into the fastener-receiving opening. The first arm 241 extends from
a base of the arm that is directly attached to the material
surrounding the fastener-receiving opening 228 to an end of the arm
that is connected to the second arm 243. The second arm extends to
a free end within the fastener-receiving opening 228. In the
illustrated embodiment, the second arm 243 is angled back toward
the base of the first arm 241. The tabs 240 are positioned within
the openings 228 such that a base 260 of the fastener 211 will
engage the tab as the fastener is being inserted into the opening
and deflect the tab to allow for passage of the fastener. In
particular, the first arm 241 will deflect away from the
fastener-receiving opening 228 and into the interior space 224 of
the spacer 210, and the second arm 243 will deflect away from the
opening toward the first arm. This allows for the base 260 of the
fastener 211 to clear the tab 240. The tab 240 will then flex back
to its pre-engaged position once the base 260 of the fastener 211
clears the tab thereby extending over the base of the fastener
preventing the fastener from being withdrawn from the opening 228.
The locking tab 240 may be broadly considered a blocking member
such that the locking tab blocks the fastener 211 from being
withdrawn from the fastener-receiving opening 228.
[0053] Referring to FIGS. 16A-17C, one difference between the
fastener 211 and fastener 11 concerns the construction of base 260
and its engagement with a driver 261. The fasteners 211 comprise
curved trabecular nails/blades configured for insertion into a
subject's bony structures (e.g., vertebrae). The nails 211 include
a base 260, a shaft 262 extending from the base, and a tip portion
264 extending from the shaft. An inner surface of the base 260
defines a receptacle 266 for receiving a head 263 of the driver 261
for inserting the nail 211 into the fastener-receiving opening 228
and driving the nail into the bony structure. The receptacle 266 is
defined by a slotted opening 267 which communicates with a rounded
interior surface 269. In the illustrated embodiment, the interior
surface 269 is free of threads. An outer circumferentially
extending surface of the base 260 defines a unique contour for
seating the base of the nail 211 in the fastener-receiving openings
228 of the spacer 210 similar to fastener 11. In addition, a rib
271 is formed on the outer surface of the base 260. The rib 271 is
configured to be received in a notch 273 formed in the
fastener-receiving opening 228 to prevent the fastener 211 from
rotating once the fastener is fully inserted into the opening, as
will be explained in greater detail below. It is also envisioned
that the nails 211 could have other configurations without
departing from the scope of the disclosure.
[0054] Referring to FIGS. 18A-19G, in use, the interior cavity 224
of the spacer 210 may be packed with bone graft material and then
inserted with an insertion tool within an interbody space between
two adjacent vertebrae in a suitable surgical procedure. Next, the
fasteners 211 can be inserted into the fastener-receiving openings
228 to anchor the spacer 210. This can be done by aligning the head
263 of the driver 261 with the slotted opening 267 of the
receptacle 266 in the head 260 of the fastener 211 and inserting
the head of the driver into the receptacle. The head 263 of the
driver 261 has a bulbous shape whereby a width of the head (FIG.
17B) is greater than a thickness of the head (FIG. 17C). Thus, the
width dimension of the head 263 can be aligned along the length of
the slotted opening 267 to insert the head of the driver 261 into
the receptacle 266 (FIGS. 18A and 18B). The driver 261 is then
rotated so that the width of the head 263 is misaligned with the
length of the slotted opening 267 preventing the head from being
withdrawn from the receptacle 266 (FIG. 18C). However, the head 263
of the driver 261 is still free to pivot or rotate within the
receptacle 266 as there is no fixed connection between the head 263
and base 260 such as when a threaded connection is used.
[0055] Referring to FIGS. 19A-19G, the driver 261 can then be used
to insert the fastener 211 into the fastener-receiving opening 228.
Because the head 263 of the driver 261 is free to pivot or rotate
within the receptacle 266, the driver can be maintained generally
at a position perpendicular to the subject's neck and spine as the
curved fastener 211 is inserted into the fastener-receiving opening
228 along an arc. Fully inserting the fastener 211 will cause the
locking tab 240 to lock the fastener in the opening 228 preventing
the fastener from being withdrawn. Additionally, the rib 271 on the
base 260 of the fastener 211 will be received in the notch 271 in
the fastener-receiving opening 228 to prevent rotation of the
fastener relative to the spacer 210 (FIGS. 20 and 21). The tab 240
is also received within a cutout 275 (FIGS. 16A and 16B) in the
base 260 of the fastener 211 further preventing rotation of the
fastener relative to the spacer 210. To decouple the driver 261
from the fastener 211, the driver is rotated to again align the
width of the head 263 with the length of the slotted opening 267
permitting the head to be pulled out of the receptacle 266.
[0056] As used herein, "open-cell metal foam" and "trabecular
lattice" refer to a porous structural component having a relatively
roughened surface, an apparent randomized filament arrangement, and
cell sizes and shapes forming an interconnected network or
labyrinth to facilitate bone in-growth.
[0057] As used herein, a "three-dimensional lattice" is a porous
structural component including non-randomized, intersecting struts
forming patterns of interconnected passages to facilitate bone
growth.
[0058] Modifications and variations of the disclosed embodiments
are possible without departing from the scope of the invention
defined in the appended claims.
[0059] When introducing elements of the present invention or the
embodiment(s) thereof, the articles "a", "an", "the" and "said" are
intended to mean that there are one or more of the elements. The
terms "comprising", "including" and "having" are intended to be
inclusive and mean that there may be additional elements other than
the listed elements.
[0060] As various changes could be made in the above constructions,
products, and methods without departing from the scope of the
invention, it is intended that all matter contained in the above
description and shown in the accompanying drawings shall be
interpreted as illustrative and not in a limiting sense.
* * * * *