U.S. patent application number 10/979915 was filed with the patent office on 2005-06-23 for quick-release drill guide assembly for bone plate.
Invention is credited to Binder, Lawrence J. JR., Ryan, Christopher J., Stihl, Pascal.
Application Number | 20050137606 10/979915 |
Document ID | / |
Family ID | 34135894 |
Filed Date | 2005-06-23 |
United States Patent
Application |
20050137606 |
Kind Code |
A1 |
Binder, Lawrence J. JR. ; et
al. |
June 23, 2005 |
Quick-release drill guide assembly for bone plate
Abstract
The present invention relates to a surgical drill-guide assembly
that can be releasably attached to a part of a bone-fixation
system, for example, a plate. The surgical drill-guide assembly of
the present invention is used for example, to guide a drill, screw,
bone fastener, or other instrument or fastener into bone.
Inventors: |
Binder, Lawrence J. JR.;
(Doylestown, PA) ; Ryan, Christopher J.; (West
Chester, PA) ; Stihl, Pascal; (West Chester,
PA) |
Correspondence
Address: |
JONES DAY
222 EAST 41ST ST
NEW YORK
NY
10017
US
|
Family ID: |
34135894 |
Appl. No.: |
10/979915 |
Filed: |
November 1, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10979915 |
Nov 1, 2004 |
|
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10639515 |
Aug 13, 2003 |
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Current U.S.
Class: |
606/96 |
Current CPC
Class: |
A61B 17/1757 20130101;
A61B 17/1728 20130101; A61B 2017/0042 20130101 |
Class at
Publication: |
606/096 |
International
Class: |
A61B 017/58 |
Claims
What is claimed is:
1. A drill-guide assembly, comprising: an alignment barrel having a
proximal end and a distal end; a bushing configured to slidably
receive the alignment barrel, the bushing having a radially
expandable forward-end and a proximal end, the forward-end
configured to be insertable within a hole or recess in a bone
plate; a release knob having serrations; and a movable ratchet gear
mechanism having a first leg, a second leg and a tail, the first
leg of the ratchet-gear mechanism connected to the alignment
barrel, the second leg of the ratchet-gear mechanism having pawls
configured and adapted to engage the serrations to hold the
alignment barrel in position, the tail of the ratchet gear
mechanism operable by a user to selectively move the ratchet-gear
mechanism, wherein, movement of the ratchet-gear mechanism slides
the alignment barrel relative to the bushing to radially expand the
forward end to releasably lock the bushing to the plate, and a
first drill guide coupled to the bushing, wherein the first drill
guide is configured to receive and guide a drill-bit.
2. The drill-guide assembly of claim 1, wherein the first drill
guide is coupled to the bushing by a first connecting element.
3. The drill-guide assembly of claim 2, wherein the first
connecting element has at least two bores for respectively
receiving at least a portion a bushing therethrough and at least a
portion of a drill guide therethrough.
4. The drill-guide assembly of claim 3, wherein the first drill
guide is further coupled to the bushing by a second connecting
element.
5. The drill-guide assembly of claim 4, wherein the second
connecting element has at least two bores for respectively
receiving at least a portion of a bushing therethrough and at least
a portion of a drill guide therethrough.
6. The drill-guide assembly of claim 5, wherein the at least two
bores of the first connecting element are separated by a first
distance, and the at least two bores of the second connecting
element are separated by a second distance, wherein the first
distance is greater than the second distance, and wherein the
second connecting element is closer to the distal end of the
forward end of the bushing than the first connecting element.
7. The drill-guide assembly of claim 5, wherein the at least two
bores of the first connecting element are separated by a first
distance, and the at least two bores of the second connecting
element are separated by a second distance, wherein the first
distance is greater than the second distance, and wherein the first
connecting element is closer to the distal end of the forward end
of the bushing than the second connecting element.
8. The drill-guide assembly of claim 3, wherein the first
connecting element further comprises a fin bore configured to
receive at least a portion of fin therethrough, wherein at least a
portion of the fin in configured to engage at least a portion of a
hole or recess when the bushing engages a bone-plate.
9. The drill-guide assembly of claim 1, further comprising a second
guide coupled to the bushing, wherein the second drill guide is
configured to receive and guide a drill-bit.
10. The drill-guide assembly of claim 9, wherein the second drill
guide is coupled to the first drill guide.
11. The drill-guide assembly of claim 10, wherein the first and
second drill guide are coupled to the bushing by a first connecting
element.
12. The drill-guide assembly of claim 11, wherein the first
connecting element has at least three bores for respectively
receiving at least a portion of the first drill guide therethrough,
at least a portion of the second drill guide therethrough, and a
least a portion of the bushing therethrough.
13. The drill-guide assembly of claim 12, wherein the first
connecting element further comprises a fin bore configured to
receive at least a portion of fin therethrough, wherein at least a
portion of the fin in configured to engage at least a portion of a
hole or recess when the bushing engages a bone-plate.
14. The drill-guide assembly of claim 12, wherein the first drill
guide and second drill guide are further coupled to the bushing by
a second connecting element.
15. The drill-guide assembly of claim 14, wherein the second
connecting element has at least three bores for respectively
receiving at least a portion of the first drill guide therethrough,
at least a portion of the second drill guide therethrough, and a
least a portion of the bushing therethrough.
16. The drill-guide assembly of claim 15, wherein the bores of the
first connecting element receiving first and second drill guides
are separated by a first distance, and the bores of the second
connecting element receiving first and second drill guides are
separated by a second distance, wherein the first distance is
greater than the second distance, and wherein the second connecting
element is closer to the distal end of the forward end of the
bushing than the first connecting element.
17. The drill-guide assembly of claim 15, wherein the bores of the
first connecting element receiving first and second drill guides
are separated by a first distance, and the bores of the second
connecting element receiving first and second drill guides are
separated by a second distance, wherein the first distance is
greater than the second distance, and wherein the first connecting
element is closer to the distal end of the forward end of the
bushing than the second connecting element.
18. The drill-guide assembly of claim 1, the first drill guide
having a longitudinal axis, and wherein when the bushing is locked
to a bone-plate, the longitudinal axis of the first drill guide is
generally aligned with a first bone-fastener hole of the
bone-plate.
19. The drill-guide assembly of claim 18, further comprising a
second drill guide configured to receive and guide a drill-bit and
coupled to the bushing, the second drill guide having a
longitudinal axis, and wherein when the bushing is locked to a
bone-plate, the longitudinal axis of the second drill guide is
generally aligned with a second bone-fastener hole of the
bone-plate.
20. The drill-guide assembly of claim 1, wherein the recess of the
bone-plate includes at least one shaped area and a slot.
21. A method for drilling holes in bone, comprising the steps of:
(a) providing a drill-guide assembly, comprising an alignment
barrel having a proximal end and a distal end; a bushing configured
to slidably receive the alignment barrel, the bushing having a
radially expandable forward-end and a proximal end, the forward-end
configured to be insertable within a hole or recess in a bone
plate; a release knob having serrations; and a movable ratchet gear
mechanism having a first leg, a second leg and a tail, the first
leg of the ratchet-gear mechanism connected to the alignment
barrel, the second leg of the ratchet-gear mechanism having pawls
configured and adapted to engage the serrations to hold the
alignment barrel in position, the tail of the ratchet gear
mechanism operable by a user to selectively move the ratchet-gear
mechanism, wherein, movement of the ratchet-gear mechanism slides
the alignment barrel relative to the bushing to radially expand the
forward end to releasably lock the bushing to the plate, and at
least a first guide coupled to the bushing, wherein the first drill
guide is configured to receive and guide a drill-bit; (b) inserting
the bushing into a recess of a bone plate; (c) aligning at least
the first drill guide with a first bone fastener hole in the
bone-plate; (d) expanding the bushing in the recess; (e) locking
the bushing to the plate; (f) inserting a drill-bit into the first
drill guide; and (g) drilling a first hole.
22. The method of claim 21, wherein at least a portion of the
forward end of the bushing is configured to fit in at least a
portion of the recess.
23. The method of claim 21, wherein the bushing is locked to the
plate by locking the alignment barrel and bushing in fixed relation
to each other.
24. The method of claim 21, wherein the drill guide assembly
further comprising a second drill guide coupled to the bushing,
wherein the second drill guide is configured to receive and guide a
drill-bit.
25. The method of claim 24, further comprising the steps of
inserting a drill-bit guide into the second drill guide, and
drilling a second hole.
26. A kit for use with drilling bones, comprising: (a) a
drill-guide assembly, comprising an alignment barrel having a
proximal end and a distal end; a bushing configured to slidably
receive the alignment barrel, the bushing having a radially
expandable forward-end and a proximal end, the forward-end
configured to be insertable within a hole or recess in a bone
plate; a release knob having serrations; and a movable ratchet gear
mechanism having a first leg, a second leg and a tail, the first
leg of the ratchet-gear mechanism connected to the alignment
barrel, the second leg of the ratchet-gear mechanism having pawls
configured and adapted to engage the serrations to hold the
alignment barrel in position, the tail of the ratchet gear
mechanism operable by a user to selectively move the ratchet-gear
mechanism, wherein, movement of the ratchet-gear mechanism slides
the alignment barrel relative to the bushing to radially expand the
forward end to releasably lock the bushing to the plate; (b) at
least first and second drill guides able to be coupled to the
bushing; and (c) at least first and second connecting elements for
coupling at least one drill guide to the bushing.
27. The kit of claim 26, wherein at least the first and second
drill guides have different lengths.
28. The kit of claim 26, wherein at least the first and second
drill guides have different diameters.
29. The kit of claim 26, wherein at least the first and second
connecting elements each have a bore for receiving at least one
drill guide therethrough and a bore for receiving a bushing
therethrough, wherein the bores of the first connecting element
have a first arrangement, and the bores of the second connecting
element have a second arrangement, and wherein the first
arrangement is substantially different than the second arrangement.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation of International Application No.
PCT/US04/026399, filed Aug. 13, 2004, and is a continuation-in-part
of U.S. Non-Provisional Patent Application No. 10/639,515, filed
Aug. 13, 2003, the entirety of which applications are expressly
incorporated herein by reference thereto.
FIELD OF THE INVENTION
[0002] The present invention relates to a surgical drill-guide
assembly that can be releasably attached to a part of a
bone-fixation system, for example, a bone plate. The surgical
drill-guide assembly of the present invention is used for example,
to guide a drill-bit, screw, bone fastener, or other instrument or
fastener into bone or other tissue.
BACKGROUND OF THE INVENTION
[0003] The use of surgical fixation plates for a variety of
orthopedic applications is widely accepted. The plates are used by
surgeons or users to stabilize, mend, or align a patient's bone as
well as alter compression of patient's bones. Plates are typically
fastened to the bones with a plurality of fasteners such as screws
that are installed through holes in the plate. Proper orientation
and alignment of fasteners and secure surgical fixation of the
plates can mitigate some of the potential future complications
after implantation.
[0004] Bone plates used, for example, in spinal applications must
be installed with special care, as the plates may be used for
long-term, intervertebral fixation, bone-fragment fixation, and/or
anterior decompression in the cervical region of the spine. The
margin for error in spinal surgery is quite small, particularly
because of the sensitivity of the spinal cord and the risk inherent
with invasive procedures around the spinal cord. In particular, the
dimensions of vertebral bone available for setting fasteners are
fairly limiting.
[0005] Each fixation screw should properly align with its
associated plate hole so that each screw is seated correctly with
the plate and enters the bone at an appropriate angle. Any
misalignment of the screw within the plate hole risks tissue damage
and spinal cord injury. In addition, improperly seated screws may
result in an unstable or insecure connection of the plate to the
bony material, thus potentially defeating the usefulness of the
plate. Locking plates, in particular, demand precise fastener
alignment.
SUMMARY OF THE INVENTION
[0006] The present invention relates to a drill-guide assembly,
which in one embodiment comprises an alignment drill-barrel, a
bushing, a dual-arm support, a ratchet-gear mechanism, a handle
member, and a release knob.
[0007] The alignment drill-barrel has a proximal end and a
forward-end also called the distal end. The proximal end of the
alignment drill-barrel preferably has two ridges, and the distal
end is generally tapered. The alignment drill-barrel is configured
to receive and guide a drill-bit, bone tap, screw, bone fastener or
other instrument into bone or other tissue. The alignment
drill-barrel preferably allows for the passage of fixation pins or
bone screws, drills, taps, or awls through it in a predetermined
trajectory.
[0008] The bushing preferably has a radially expandable forward-end
and a proximal end, wherein the forward-end is configured to engage
a fastener hole in a bone-plate. The radially expandable forward
end of the bushing preferably has a plurality of finger portions.
The radially expandable forward end also preferably has a shoulder,
neck, and an outwardly projecting rim disposed forward of the neck.
The bushing is configured to slidably receive the alignment
drill-barrel. Sliding the alignment drill-barrel toward the forward
end of the bushing preferably expands the forward end of the
bushing to secure the drill-guide assembly in a bone-plate.
[0009] The dual-arm support in one embodiment is generally
"L-shaped" with the two ends of the "L" forming an obtuse angle.
The dual-arm support preferably has a space provided in its center
region. In one embodiment, the end portion, which is generally
horizontally disposed, comprises a pivot-hole for inserting a pivot
screw. At one end, the dual-arm support is immovably or fixedly
connected to the proximal end of the bushing, while at its other
end, the dual-arm support is immovably connected to the front end
of the handle member.
[0010] The handle member in an exemplary embodiment has a front end
and a back end. It is generally oval shaped with broad grooves on
top to provide better grip for the surgeon or user using the
drill-guide assembly. The handle may be hollow or solid depending
upon design choice.
[0011] The ratchet-gear mechanism in one embodiment is generally
"Y-shaped" and is housed within the space of the dual-arm support.
At one end, the first leg of the ratchet-gear mechanism is
pivotably connected to the dual-arm support at a pivot-point. That
end of the first leg further extends beyond the pivot point forming
a C-shaped vice-grip. The C-shaped vice-grip attaches to the
alignment drill-barrel. The C-shaped vice-grip grasps the alignment
drill-barrel in between the two ridges at the proximal end. In a
preferred embodiment, the plane of the C-shaped vice-grip is
generally perpendicular to the axial direction of the alignment
drill-barrel, and the bushing. The second leg of the Y-shaped
ratchet-gear mechanism comprises pawls on the outer side which
permit incremental swiveling of the ratchet-gear mechanism in a
plane perpendicular to the plane of C-shaped vice-grip. The
tail-end of the Y-shaped ratchet-gear mechanism acts as a trigger
and generally moves in a rotational motion relative to the pivot
point in a direction toward or away from the handle member.
Movement of the ratchet-gear mechanism, and particularly the
C-shaped vice grip, slides the alignment drill-barrel relative to
the bushing.
[0012] The release knob in an exemplary embodiment has a curved
longitudinal member with a base. The base has serrations on one
side of its circumferential border and a hole on the other side.
The release knob is pivoted through the hole in the base about a
dowel pin that is attached to the dual-arm support.
[0013] When the tail of the Y-shaped ratchet-gear mechanism is
pressed by a finger of a user in a rotary motion in a direction
toward the handle member, the distal end of the alignment
drill-barrel is urged into the bushing which in turn, expands the
forward-end of the bushing, thus locking the bushing within a hole
or recess of the bone-plate. The bushing is configured and
dimensioned to expand within a bone-plate hole or recess such that
it is releasably locked to the bone-plate.
[0014] When the Y-shaped ratchet-gear mechanism engages the release
knob, the pawls on the outer surface of the second leg of the
Y-shaped ratchet-gear mechanism engage the serrations on the
release knob to lock the drill-guide to the bone-plate. The
alignment drill-barrel preferably self-aligns with the axis of the
fastener hole in the plate.
[0015] When the release knob is further pressed, the pawls are
disengaged from the serrations, and the Y-shaped ratchet-gear
mechanism returns to an unactuated position, preferably by action
of a biasing member such as a spring. The Y-shaped ratchet-gear
mechanism, in turn, through its C-shaped vice-grip moves the
alignment drill-barrel in a longitudinal direction along its axis,
away from the fingers. As a result, the bushing assumes a retracted
position thereby disengaging the hole or recess.
[0016] Another embodiment of a drill-guide assembly is described,
comprising an alignment barrel having a proximal end and a distal
end; a bushing configured to slidably receive the alignment barrel,
the bushing having a radially expandable forward-end and a proximal
end, the forward-end configured to be insertable within a hole or
recess in a bone plate; a release knob having serrations; and a
movable ratchet gear mechanism having a first leg, a second leg and
a tail, the first leg of the ratchet-gear mechanism connected to
the alignment barrel, the second leg of the ratchet-gear mechanism
having pawls configured and adapted to engage the serrations to
hold the alignment barrel in position, the tail of the ratchet gear
mechanism operable by a user to selectively move the ratchet-gear
mechanism, wherein, movement of the ratchet-gear mechanism slides
the alignment barrel relative to the bushing to radially expand the
forward end to releasably lock the bushing to the plate, and a
first drill guide coupled to the bushing, wherein the first drill
guide is configured to receive and guide a drill-bit.
[0017] The first drill guide may be coupled to the bushing by a
first connecting element. The first connecting element may have at
least two bores for respectively receiving at least a portion a
bushing therethrough and at least a portion of a drill guide
therethrough. The first drill guide may also be further coupled to
the bushing by a second connecting element, and the second
connecting element may have at least two bores for respectively
receiving at least a portion of a bushing therethrough and at least
a portion of a drill guide therethrough.
[0018] At least two bores of the first connecting element may be
separated by a first distance, and the at least two bores of the
second connecting element may be separated by a second distance,
wherein the first distance may be greater than the second distance,
and wherein the second connecting element may be closer to the
distal end of the forward end of the bushing than the first
connecting element. Alternatively, the first connecting element may
be closer to the distal end of the forward end of the bushing than
the second connecting element.
[0019] The first connecting element may further comprise a fin bore
configured to receive at least a portion of fin therethrough,
wherein at least a portion of the fin in configured to engage at
least a portion of a hole or recess when the bushing engages a
bone-plate.
[0020] The drill-guide assembly may further comprise a second guide
coupled to the bushing, wherein the second drill guide is
configured to receive and guide a drill-bit. The second drill guide
may be coupled to the first drill guide. The first and second drill
guide may be coupled to the bushing by a first connecting element.
The first connecting element may have at least three bores for
respectively receiving at least a portion of the first drill guide
therethrough, at least a portion of the second drill guide
therethrough, and a least a portion of the bushing
therethrough.
[0021] The first connecting element may further include a fin bore
configured to receive at least a portion of fin therethrough,
wherein at least a portion of the fin in configured to engage at
least a portion of a hole or recess when the bushing engages a
bone-plate.
[0022] The first drill guide and second drill guide may further be
coupled to the bushing by a second connecting element.
[0023] The second connecting element may also have at least three
bores for respectively receiving at least a portion of the first
drill guide therethrough, at least a portion of the second drill
guide therethrough, and a least a portion of the bushing
therethrough.
[0024] The bores of the first connecting element receiving first
and second drill guides are separated by a first distance, and the
bores of the second connecting element receiving first and second
drill guides are separated by a second distance, wherein the first
distance is greater than the second distance, and wherein the
second connecting element may be closer to the distal end of the
forward end of the bushing than the first connecting element.
Alternatively, the first connecting element may be closer to the
distal end of the forward end of the bushing than the second
connecting element.
[0025] The first drill guide may have a longitudinal axis, and when
the bushing is locked to a bone-plate, the longitudinal axis of the
first drill guide may generally be aligned with a first
bone-fastener hole of the bone-plate. The drill-guide assembly may
further comprise a second drill guide configured to receive and
guide a drill-bit and coupled to the bushing, the second drill
guide having a longitudinal axis, and when the bushing is locked to
a bone-plate, the longitudinal axis of the second drill guide may
be generally aligned with a second bone-fastener hole of the
bone-plate. The recess of the bone-plate includes at least one
shaped area and a slot.
[0026] An alternative method for drilling holes in bone is also
described, comprising the steps of: (a) providing a drill-guide
assembly, comprising an alignment barrel having a proximal end and
a distal end; a bushing configured to slidably receive the
alignment barrel, the bushing having a radially expandable
forward-end and a proximal end, the forward-end configured to be
insertable within a hole or recess in a bone plate; a release knob
having serrations; and a movable ratchet gear mechanism having a
first leg, a second leg and a tail, the first leg of the
ratchet-gear mechanism connected to the alignment barrel, the
second leg of the ratchet-gear mechanism having pawls configured
and adapted to engage the serrations to hold the alignment barrel
in position, the tail of the ratchet gear mechanism operable by a
user to selectively move the ratchet-gear mechanism, wherein,
movement of the ratchet-gear mechanism slides the alignment barrel
relative to the bushing to radially expand the forward end to
releasably lock the bushing to the plate, and at least a first
guide coupled to the bushing, wherein the first drill guide is
configured to receive and guide a drill-bit; (b) inserting the
bushing into a recess of a bone plate; (c) aligning at least the
first drill guide with a first bone fastener hole in the
bone-plate; (d) expanding the bushing in the recess; (e) locking
the bushing to the plate; (f) inserting a drill-bit into the first
drill guide; and (g) drilling a first hole.
[0027] At least a portion of the forward end of the bushing may be
configured to fit in at least a portion of the recess. The bushing
may be locked to the plate by locking the alignment barrel and
bushing in fixed relation to each other. The drill guide assembly
may further comprise a second drill guide coupled to the bushing,
wherein the second drill guide is configured to receive and guide a
drill-bit.
[0028] The method may further comprise the steps of inserting a
drill-bit guide into the second drill guide, and drilling a second
hole.
[0029] A kit for use with drilling bones is also described,
comprising: (a) a drill-guide assembly, comprising an alignment
barrel having a proximal end and a distal end; a bushing configured
to slidably receive the alignment barrel, the bushing having a
radially expandable forward-end and a proximal end, the forward-end
configured to be insertable within a hole or recess in a bone
plate; a release knob having serrations; and a movable ratchet gear
mechanism having a first leg, a second leg and a tail, the first
leg of the ratchet-gear mechanism connected to the alignment
barrel, the second leg of the ratchet-gear mechanism having pawls
configured and adapted to engage the serrations to hold the
alignment barrel in position, the tail of the ratchet gear
mechanism operable by a user to selectively move the ratchet-gear
mechanism, wherein, movement of the ratchet-gear mechanism slides
the alignment barrel relative to the bushing to radially expand the
forward end to releasably lock the bushing to the plate; (b) at
least first and second drill guides able to be coupled to the
bushing; and (c) at least first and second connecting elements for
coupling at least one drill guide to the bushing.
[0030] At least the first and second drill guides may have
different lengths, and at least the first and second drill guides
may have different diameters. At least the first and second
connecting elements may each have a bore for receiving at least one
drill guide therethrough and a bore for receiving a bushing
therethrough, wherein the bores of the first connecting element
have a first arrangement, and the bores of the second connecting
element have a second arrangement, and wherein the first
arrangement may be substantially different than the second
arrangement.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] Preferred features of the present invention are disclosed in
the accompanying drawings, wherein similar reference characters
denote similar elements throughout the several views. While the
presentation is desired and its features presented according to
certain illustrated embodiments it is to be understood that the
invention is not so limited to the particular embodiments shown and
described, wherein:
[0032] FIG. 1 is a perspective view of a first embodiment of a
drill-guide assembly;
[0033] FIG. 2 is a cross-sectional view of an embodiment of an
alignment drill-barrel that may be used with the assembly of FIG.
1;
[0034] FIG. 3 is a partial cross-sectional view of another
embodiment of an alignment drill-barrel that may be used with the
assembly of FIG. 1;
[0035] FIG. 4 is a cross-sectional view of an embodiment of the
bushing;
[0036] FIG. 5 is a side view of the dual-arm support attached to
the bushing and handle member;
[0037] FIG. 6 is a perspective view of the Y-shaped ratchet-gear
mechanism;
[0038] FIG. 6A is a side view of the Y-shaped ratchet-gear
mechanism;
[0039] FIG. 6B is a perspective view of the drill-guide assembly
showing the ratchet-gear mechanism connected to the dual-arm
support;
[0040] FIG. 7 is a side view of the release knob;
[0041] FIG. 7A is a perspective view of the ratchet-gear mechanism
engaging the release knob;
[0042] FIG. 8 is a side view of the handle member of the
drill-guide assembly;
[0043] FIG. 9 is a side view of the bushing with fingers in
retracted position;
[0044] FIG. 10 is a side view of the bushing with fingers in
expanded position; and
[0045] FIG. 11 is a perspective view of the drill-guide assembly of
FIG. 1 engaged to a bone-plate.
[0046] FIG. 12A is a perspective view of another embodiment of a
drill-guide assembly with drill guides;
[0047] FIG. 12B is another perspective view of the assembly of FIG.
12A;
[0048] FIG. 12C is a partial top view of an exemplary bone plate
that can be used with the assemblies of FIGS. 1 and 12A;
[0049] FIG. 13A is a top view of a proximal connecting element for
use with the assembly of FIG. 12A; and
[0050] FIG. 13B is a top view of a distal connecting element for
use with the assembly of FIG. 12A.
DETAILED DESCRIPTION OF THE INVENTION
[0051] Referring to FIG. 1, there is shown an exemplary surgical
drill-guide assembly 5, which is adapted for use with a cervical
spine-locking bone plate having a plurality of fastener holes.
While the surgical drill-guide assembly is described in conjunction
with a cervical locking plate it will be appreciated that the
reference to a cervical locking plate is only exemplary, and that
the surgical drill-guide assembly can be used with a variety of
bone plates, including a locking and a nonlocking bone-plate as
well as for example, bone plates for long bones, maxillofacial
applications, etc.
[0052] This embodiment of a drill-guide assembly 5 can be secured
or locked into a fastener hole in a bone plate. A related
embodiment of a drill-guide assembly 500 that can be secured or
locked into a drill recess 354 is shown infra in FIGS. 12A-13B.
Locking or securing may facilitate precision in the surgical
procedure, for example, drilling or fastening screws or other
similar fasteners. Moreover, the drill-guide can be quickly
detached and released from the bone-plate improving the speed of
surgical procedures involving drilling or similar procedures.
[0053] Drill-guide assembly 5 may include an alignment assembly 15,
a release knob 100, a handle member 250, a ratchet-gear mechanism
50, and a dual-arm support 10.
[0054] The alignment assembly 15 may comprise an alignment
drill-barrel 150 and a bushing 200. A surgeon or a user can
releasably attach the alignment assembly 15 in the fastener hole
352 of a bone-plate 350. Other attachment options are discussed
infra, particularly in relation to FIGS. 12A-13B. A drill-bit or
other such instrument can be inserted into and through the
alignment assembly 15.
[0055] Referring to FIG. 2, an embodiment of the alignment
drill-barrel 150 is shown. The alignment drill-barrel 150 may have
a through bore 185 from its proximal end 174 to its distal end 172.
A drill-bit or other instrument may be inserted through the bore
185. In the embodiment of FIG. 2, the drill-barrel comprises a
first hollow cylindrical section 156 with an annular diameter of
x.sub.12, a second hollow cylindrical section 158 with an inside
annular diameter of x.sub.18, and a third hollow cylindrical
section 160 with an inside annular diameter of x.sub.24, wherein
x.sub.24 is smaller than x.sub.18, and x.sub.18 is smaller than
x.sub.2. The outside surface of the alignment drill-barrel 150
comprises a shoulder 162 and a shoulder 164 wherein the outside
diameter of the first section 166 is x.sub.14 which is greater than
the outside diameter x.sub.20 of the second section 168.
x.sub.14has an exemplary diameter of 3 mm to 10 mm, preferably
about 8 mm. The third section 170 is a conical section that tapers
from an outside diameter x.sub.22 at shoulder 164 to a diameter
x.sub.26 at the distal end 172. The proximal end 174 of the
alignment drill-barrel 150 preferably has first circular ridge 152
and second circular ridge 154. The first and the second circular
ridges 152 and 154 respectively, have an outside diameter
x.sub.16.
[0056] In this embodiment, the first circular ridge 152 is flush
with the proximal end 174 of the alignment drill-barrel 150. The
conical section 170 tapers from an outside diameter x.sub.22 at the
transition 164 to an outside diameter x.sub.26 at end 172.
Preferably, inner diameter x.sub.24 is constant along the length of
conical section 170 of alignment drill-barrel 150 as defined along
center line 180.
[0057] Referring to FIG. 3, an alignment drill-barrel 150 according
to another embodiment is shown. In FIG. 3, alignment drill-barrel
150 is hollow with a cylindrical section 182 and a tapered, conical
section 184 to facilitate movement of alignment drill-barrel 150
within bushing 200. Cylindrical section 182 has outside diameter
x.sub.5, while conical section 184 tapers from an outside diameter
x.sub.5 at the transition 186 to an outside diameter x.sub.6 at the
distal end 188. Preferably, inner diameter x.sub.7 may be constant
along the length of alignment drill-barrel 150 as defined along
center line 190.
[0058] Referring to FIG. 4, a bushing is shown. Bushing 200 may
coaxially receive alignment drill-barrel 150 about a central line
240. Bushing 200 may be substantially symmetrical about line 240.
The forward end 222 of bushing 200 may preferably be comprised of
longitudinally extending fingers 210. Individual fingers 210 may be
separated by slits 204 extending longitudinally between adjacent
fingers 210. Slits 204 as shown, for example, in FIG. 4, may
include a circular portion 206 that serves to minimize stress
concentration when fingers 210 are flexed. Fingers 210 may be
resiliently biased inwardly and naturally assume an inward
disposition when in a relaxed state. At a front portion of the
expandable forward end 202 of bushing 200, the fingers 210 may form
a radially expandable circumferential neck 208. At the back end of
and adjacent to neck 208 may preferably be a shoulder 212.
[0059] Neck 208 may span a length that is slightly longer than the
thickness of the fastener hole wall from the bone-side surface to
the top surface of a bone-plate. Thus, neck 208 can be inserted
into the bone-plate fastener hole 352 and the fingers 210 expanded
to secure the bushing 200 to the plate. More particularly, movement
of alignment drill-barrel 150 within bushing 200 may expand fingers
210 to secure the bushing 200 to the bone plate. In this manner,
the drill-guide assembly can be secured to the plate, restricting
relative movement. In a preferred embodiment, fingers 210 forming a
radially expandable rim 214 may be provided at the front end of and
adjacent to neck 208.
[0060] In another embodiment, the distal end 222 of the bushing 200
may not contain the rim 214, the neck 208 or the shoulder 212, but
instead has a tapered end with the inner and the outer diameter of
the tapered end decreasing from point 220 shown in FIG. 4. In such
an embodiment, the taper is such that it may fit freely through a
fastener hole in a bone plate.
[0061] In alternate embodiments, no rim may be used. The several
portions of bushing 200, i.e., the neck 208, the shoulder 212, and
the rim 214, may preferably be a single piece of material of
unitary construction.
[0062] In other alternate embodiments, fingers 210 need not include
a shoulder, neck, and/or a rim. Instead, for example, a small pin
may be used to secure the bushing to the plate. In an alternatively
preferred embodiment, the inward bias of fingers 210 is selected to
produce the desired friction with the bone-plate 350 so that the
fingers 210 fit snugly within the bone-plate fastener hole 352 (or
drill recess 354, as discussed infra in relation to FIGS. 12A-13B),
preferably allowing operation of handle member 250 with only one
hand. Alternative resiliency for fingers 210 may be varied to suit
the purpose of the design.
[0063] In a preferred embodiment bushing 200 has one or more
longitudinal slots on its side 224 in axial direction 240 just
above the circular portion 206. These slots provide better cleaning
during autoclave or other disinfection and/or cleaning
procedures.
[0064] Referring to FIG. 4, bushing 200 has a circumferential ridge
218 with an outer diameter x.sub.3, and a region 216 has an outer
diameter x.sub.4. x.sub.4 has an exemplary dimension of 4 mm to 20
mm, preferably about 8 mm.
[0065] As shown in FIG. 5, in one embodiment, dual-arm support 10
connects the handle member 250 to the alignment assembly 15. More
specifically, in the exemplary embodiments of FIGS. 1 and 2, the
dual-arm support 10 is fixedly connected at its end to the proximal
end 174 of the alignment assembly 15. Dual-arm support 10
preferably is generally "L-shaped" with first part 14 connected to
bushing 200. More specifically, end 12 of dual-arm support 10 is
attached to ridge 218 at the proximal end 242 of the bushing
200.
[0066] The dual-arm support 10 is preferably fixed with the bushing
200 by welding. In an alternative embodiment, friction fitting,
press fitting, and such can be used. Outer diameter x.sub.3 of
ridge 218 is about the same size as inner diameter x.sub.1 of the
clamp 12 of the dual-arm support 10. Bushing 200 may also be fixed
to dual-arm support 10 by releasable fastener means. First part 14
is generally perpendicular to the axial direction of the alignment
assembly 15 or the bushing 200. The second part 16 of the dual-arm
support 10 preferably forms an obtuse angle .theta..sub.d1 with the
first part 14 of the dual-arm support 10. .theta..sub.d1 may range
from about 90 to about 180, and more preferably from about 105 to
about 135. Dual-arm support 10 and handle member 250 are fixedly
connected by a dowel pin 20 at the front end of the handle member
250, so that they are immovable with respect to each other. In the
preferred embodiment, handle member 250 is located remotely from
the drilling site, thereby increasing visibility near the locking
bone plate 350.
[0067] As shown in FIG. 5, the second part 16 of the dual-arm
support 10 may be attached to the first part 14 by a dowel pin 18,
or the dual-arm support 10 may be an integral, monolithic
construction. The second part 16 of the dual-arm support 10 also
forms an obtuse angle .theta..sub.d2 with the handle member 250.
.theta..sub.d2 may range from about 90 to about 180, and more
preferably from about 105 to about 135. The handle member 250 and
the dual-arm support 10 generally form an "S" shape or a zigzag
shape, and in a preferred embodiment, the longitudinal axis 24 of
the first part 14 and the longitudinal axis 26 of the second part
16 lie in the same plane. The longitudinal axis 280 of the handle
member 250 also preferably lies in the same plane as the
longitudinal axis 24 of the first part 14 and the longitudinal axis
26 of the second part 16 of the dual-arm support 10. Preferably the
longitudinal axis 24 of the first-part 14 of the dual-arm support
10 is generally parallel with the longitudinal axis 280 of the
handle member 250.
[0068] Referring to FIG. 6, there is shown an exemplary embodiment
of the ratchet-gear mechanism 50. The ratchet-gear mechanism 50
allows the user to manipulate the locking and release of the
drill-guide assembly 5 with the bone-plate 350 by engagement and
disengagement, respectively, of the pawls 58 with the serrations
102. The ratchet-gear mechanism 50, in a preferred embodiment is
generally "Y-shaped" with a first leg 52, a second leg 54, and a
tail 56.
[0069] The first leg 52 of the ratchet-gear mechanism comprises a
generally C-shaped vice-grip 60 at its end, and a pivot hole 62 for
insertion of a pivot screw 64. The C-shaped vice-grip 60 grips the
alignment drill-barrel 150 in between the first ridge 152 and
second ridge 154 (see also FIG. 2) located at the end 174 of the
drill-barrel 150. As shown in FIG. 6A, in a preferred embodiment,
the plane of the C-shaped vice-grip 60 that forms an anterior
portion of the first leg 52 of the Y-shaped ratchet-gear mechanism
50 makes an acute angle .theta..sub.d with the longitudinal axis 64
of the first leg 52 of the Y-shaped ratchet-gear mechanism 50. At
the point of inflexion between the longitudinal first leg 52 and
the C-shaped vice grip 60, pivot screw 64 and hole 62 are located.
This pivot mechanism 62 helps the movement of the alignment
drill-barrel 150. In a preferred embodiment, the acute angle is
from about 25 to about 45. In a further preferred embodiment the
acute angle .theta..sub.d is such that when the ratchet-gear
mechanism 50 is completely disengaged from the serrations 102 of
the release knob 100, the alignment drill-barrel 150 can be removed
from the bushing 200 in a longitudinal direction away from the
fingers 210 by moving the ratchet-gear mechanism 50 in a direction
away from the handle member 250, about the pivot screw 64.
.theta..sub.d may be 0 to 90, with an exemplary dimension of
60.
[0070] The second leg 54 of the Y-shaped ratchet-gear mechanism 50
comprises horizontal pawls 58 which engage serrations 102 at the
end of the release knob 100. The tail 56 of the Y-shaped
ratchet-gear mechanism 50 acts as a trigger for a user to apply a
force to actuate movement of the alignment drill-barrel 150.
[0071] Referring to FIG. 7, the release knob 100 is pivoted about a
dowel pin 106 which is inserted through the dowel pin hole 104 in
the release knob 100, and the release knob hole 142 in the second
part 16 of the dual-arm support 10. With pivotal support from the
dowel pin 106, the serrations 102 on the surface of the release
knob 100 can engage with the pawls 58 on the second leg 54 of the
Y-shaped ratchet-gear mechanism, when the tail 56 (trigger) of the
Y-shaped ratchet-mechanism is pressed or moved in a direction
toward the handle member 250. In a preferred embodiment, the
release knob 100 has a rubber sleeve 106 or a sleeve made from a
material which provides a firm traction when the surgeon or the
user presses the release knob 100. Alternatively, or additionally
the surface of the release knob may have surface texturing to
increase the traction when a surgeon or a user manipulates the
release knob 100.
[0072] Referring to FIG. 8, handle member 250 is shown. Handle
member 250 is generally oval shaped with broad grooves 252 on top
to provide better grip to the surgeon or user when using the
drill-guide assembly 5. At the front end 254 of the handle member
250, there are two cavities, the first cavity 256 and the second
cavity 258. The first cavity 256 has an axis along line 260 and the
second cavity 258 has an axis along line 270. The first cavity 256
houses compression spring 272 and the second cavity 258 houses the
dual-arm support 10, or more specifically the second part 16 of the
dual-arm support 10. The second part 16 of the dual-arm support 10
is fixed to the handle member 250 by a dowel pin 20. The dowel pin
20, in a preferred embodiment, is generally perpendicular to the
axis 280 of the handle member 250. Exemplary dimensions of the
handle are 100 to 150 mm long with a width at the widest point of
15 mm to 40 mm.
[0073] When a surgeon or a user presses the trigger 56, toward
handle member 250, the ratchet-gear mechanism 50 swivels. Due to
the movement of the Y-shaped ratchet-gear mechanism 50 in the
direction of the handle member 250, the alignment drill-barrel 150
moves the bushing 200 in the downward direction toward the
bone-plate 350. Due to the conical shape 170 of the alignment
drill-barrel 150 (FIG. 2), the fingers 210 on the bushing 200
expand in an outward direction as the front end 172 of alignment
drill-barrel 150 approaches the front edge 214 of bushing 200. When
the outward diameter of the fingers 210 matches that of the
fastener hole 352, the drill-guide assembly 5 locks to the
bone-plate 350. A surgical drill-bit 400 or any other appropriate
bit, screw, tap, awl, or such device, can be inserted through the
alignment drill-barrel 150.
[0074] Alignment drill-barrel 150 may be configured and dimensioned
to be slidably received within bushing 200. The alignment
drill-barrel 150 and bushing 200 may cooperate to permit
drill-guide assembly 5 to lock to a bone plate 350. The conical
section 184 of the alignment drill-barrel 150 may cooperate with
fingers 210 of bushing 200 to expand fingers 210 when the alignment
drill-barrel 150 is moved into a locked position. The conical
section 184 of alignment drill-barrel 150 may push outwardly
against the inner surface of the bushing 200 as alignment
drill-barrel 150 is moved forward to expand the forward end 214 of
the bushing 200. In this embodiment, the conical section mates with
and pushes against the inner surface of the bushing 200 forward of
circular portion 206 of slits 204 in fingers 210, to push the
fingers 210 radially outward (see FIG. 4).
[0075] Alignment drill-barrel 150 may be aligned within bushing
200, such that center line 240 or 190 may be collinear with line
180. When bushing 200 is placed in a fastener hole of a bone plate,
and ratchet-gear mechanism 50 is actuated such that the almost
fully actuated position is reached (i.e. when trigger 56 is
substantially parallel to handle member 250), end 172 of alignment
drill-barrel 150 may be substantially coplanar with rim 214 of
bushing 200. It should be noted that alignment drill-barrel 150 may
be coaxially received in bushing 200 which may also be the path of
surgical drill-bit 400 inserted in cannula 182 of the alignment
drill-barrel 150.
[0076] Generally, a surgeon or user should continue to depress the
trigger 56 and handle member 250 toward each other to maintain an
actuated position of Y-shaped ratchet-gear mechanism. Depending on
the size of the fastener hole 352 (or drill recess 354, see FIGS.
12A-13B) and the firmness of the locking desired, the pawls 58
located on the second leg 54 of the Y-shaped ratchet-gear mechanism
50 may engage with the serrations 102 on the release knob 100
holding the ratchet-gear mechanism 50 in place. The release knob
100 preferably may be held firm in its position by the compression
force of the spring mechanism 272, which may be located at the
front end 254 inside the cavity 256 of the handle member 250. With
the ratchet-gear mechanism 50 provided in this drill-guide assembly
5, the serrations 102 on the release knob 100 can be used to
releasably lock Y-shaped ratchet-gear mechanism 50 at the desired
level of actuation. This may obviate the need for a surgeon or user
to continue to depress the trigger 56 relative to handle member 250
after desired actuation has occurred. The pawls 58 on the second
leg 54 of the Y-shaped ratchet-gear mechanism 50 may engage the
serrations 102 on the release knob 100 when the trigger 56 is
pressed sufficiently. The release knob 100 may be held in a fixed
position as a result of the compression force exerted by the
compressed spring 272.
[0077] When the release knob 100 is pressed in the direction of the
front end 254 of the handle member 250, the spring member 272 may
be compressed, the pawls 58 may be disengaged from the serrations
102, and the Y-shaped ratchet-gear mechanism 50 may become
unactuated. When the Y-shaped ratchet-gear mechanism 50 is
unactuated, the force that is keeping the alignment drill-barrel
150 in a position toward fingers 210 may be released. As a result,
the alignment drill-barrel 100 may no longer be pushing the fingers
210 on the bushing 200 in an outward direction toward the
bone-plate 350. The alignment drill-barrel 150 can be then moved in
a longitudinal direction away from the fingers 210 on the bushing
200. As a result, the bushing 200 may assume a retracted position
as demonstrated in FIG. 9. Once the fingers 210 retract, the
drill-assembly 5 may unlock from the fastener hole 352 or drill
recess 354 of the bone-plate 350 and the user or surgeon can
withdraw it.
[0078] When the release knob 100 is pressed to further compress the
spring, the pawls 58 may disengage from serrations 102, thereby
de-actuating the Y-shaped ratchet-gear mechanism 50, which in turn,
through the pivot action at the pivot screw 64 may result in the
movement of the alignment drill-barrel 150 in a direction away from
the bone-plate 350.
[0079] Advantageously, a surgeon or user can operate drill-guide 5
with only one hand, due to the ergonomic positioning of trigger 56
and handle member 250. With the embodiment illustrated in FIG. 1, a
user can attach the drill-guide by using a finger, such as an index
finger, to engage and manipulate the tail 56 of the ratchet-gear
mechanism 50, and while a second different finger, such as a thumb,
to engage and manipulate the release knob 100.
[0080] When the alignment drill-barrel 150 is in the unlocked
position as shown in FIG. 9, the conical section 184 allows fingers
210 to return to a relaxed, contracted position. This allows
bushing 200 to be inserted and retracted from plate fastener hole.
The inner surface of the bushing 200 forward of steps 220 in
bushing 200 is preferably tapered at an angle .theta..sub.B to line
240 that is about 1 degree more than taper angle .theta..sub.T of
conical sections 184, and preferably angle .theta..sub.B is about 4
degrees. A desirable amount of movement of alignment drill-barrel
150 within bushing 200 is thus provided to bias fingers 210 of
bushing 200 from a contracted position to an expanded position.
Alternative taper angles of conical section 184 and inner surface
of bushing 200 may be chosen according to varying design criteria.
In addition, a preferred, short movement of trigger 56
(ratchet-gear mechanism 50) is required to expand and contract
fingers 210 of bushing 200.
[0081] Before and during bone plate implantation, the surgeon or
user may insert the expandable distal end 222 of bushing 200 in
particular neck 208 and rim 214, into fastener hole 352 or drill
recess 354 in a bone plate 350. By pressing trigger 56 of the
Y-shaped ratchet-gear mechanism 50 relative to the handle member
250, the surgeon or user may grasp and manipulate the plate 350
without an additional plate holder if so desired. Friction between
the forward conical section 184 of the alignment drill-barrel 150
and the inner surface of fingers 210 especially at neck 208 and rim
214 may retain the expandable distal end 222 of bushing 200 in an
expanded, locked position. Thus, when bushing 200 is in the
expanded, locked position in a fastener hole of a plate placed in
position for implantation, movement of the plate during the
drilling operation can be minimized.
[0082] Drill-barrel 150 may preferably be sized so that once the
bone plate 350 is properly positioned over the implantation site
and bushing 206 is locked to the plate, the insertion point of a
surgical drill-bit 400 at the proximal end of drill-barrel 150, is
located at a distance beyond the patient's body such that a
spinning surgical drill-bit 400 will not laterally reach or harm
surrounding tissues that the surgeon or user does not intend to
drill.
[0083] Preferably, the surgical drill-bits used with surgical
drill-guide assembly 5 are configured and dimensioned to drill
holes of about 12, 14, or 16 mm in depth. Suitable drill-bits
typically have integral stops so that when the drill-bits are used
with alignment drill-barrel of an established length, the holes
produced by the drill-bit will not be deeper than the intended
depth using a given bit. The stops may be positioned to abut the
upper surfaces at the proximal end of drill-barrel 150, when a
drill-bit has been inserted in the barrel to a particular
depth.
[0084] Another embodiment of a drill-guide assembly 500 is shown in
FIGS. 12A-13B. As with drill-guide assembly 5 (see FIG. 1, supra),
assembly 500 may include an alignment assembly 515, release knob
600, handle member 650, ratchet-gear mechanism 550, bushing 450
with fingers 570 and slits 572, and a dual-arm support 610, the
components of which may exhibit some or all of the characteristics
of the corresponding components described above in relation to
assembly 5.
[0085] Drill-guide assembly 500 may also include first and second
drill guides 502, 504 for use with surgical drill (e.g., 400).
Drill guides 502, 504 may be connected to bushing 450 by proximal
and distal connecting elements 510, 512, which are discussed in
more detail below in relation to FIGS. 13A-13B. Drill guides 502,
504 may also have proximal ends 506, 508 and distal ends 516, 518,
with a bores 507, 509 extending therebetween. The bores 507, 509
should be sized to receive at least a portion of a surgical drill,
and should preferably align with a bone fastener hole 352 during
use. Drill guides 502, 504 may have a length L.sub.1, L.sub.2 (see
FIGS. 12A-12B) from about 150 mm to about 350 mm, and more
preferably, a length of about 260 mm. Generally, drill guides 502,
504 have a greater length than bushing 450. Drill guide lengths
L.sub.1, L.sub.2 may or may not be approximately equal.
[0086] Bores 507, 509 may have a variable diameter B.sub.1, B.sub.2
along the length L.sub.1, L.sub.2 of drill guides 502, 504. Bore
diameter B.sub.1, B.sub.2 may have a diameter of about 5 mm to
about 15 mm at proximal ends 506, 508 and/or distal ends 516,
518.
[0087] Drill-guide assembly 500 may be used with the plate shown in
FIG. 12C. Plate 350 may have a plurality of fastener holes 352 and
at least one drill recess 354 in body 351. Recess 354 may have
shaped areas 356a, 356b with midpoint 358a, 358b, with a distance
MPD between midpoints. Recess 354 may also have a slot area 360
extending between shaped areas 356a, 356b.
[0088] Alternatively, recess 354 may at least partially comprise a
polygonal shape, such as a hexagon, rectangle, or square. The
recess 354 may also take the shape of a plurality of polygonal
shapes, for example, two overlapping hexagons may comprise the
shape of the recess 354 to form a combination-polygonal recess.
These embodiments may be particularly useful in bone-plates with a
reduced area in which to place a recess 354 for purposes of
aligning assembly 500.
[0089] In use, the fingers 570 of bushing 450 of assembly 500 may
be inserted into drill recess 354, instead of fastener hole 352.
The engagement and/or locking of the bushing 450 within a drill
recess 354 may take some or all of the characteristics of the
engagement and/or locking of bushing 200 with a fastener hole 352,
as described above. Generally, it may be preferable for the bushing
450 to engage the drill recess 354 at shaped area 356a, 356b. The
placement and locking of bushing 450 at shaped area 356a may align
drill guides 502, 504 with fastener holes 352a, 352b, respectively.
Similarly, the placement and locking of bushing 450 at shaped area
356b may align drill guides 502, 504 with fastener holes 352c,
352d, respectively.
[0090] Assembly 500 may also have a fin 514 to assist the
insertion, locking, and/or alignment of the assembly in a drill
recess 354. Fin 514 may generally be an elongated component, with
at least a portion of the fin 514 secured in the distal connecting
element 512 at fin bore 536 (see FIG. 13B). In use, when the
bushing engages a shaped area 356a, 356b, the fin concurrently
engages slot 360. The fin 514 may or may not touch the sides of the
slot 360 when the bushing 450 is fully inserted into a shaped area
356a, 356b.
[0091] FIG. 13A is a top view of a proximal connecting element 510,
and FIG. 13B is a top view of a distal connecting element 512.
Proximal connecting element 510 may have a bushing bore 530a, and
first and second drill guide bores 532a, 534a. First and second
drill guide bores 532a, 534a may have respective midpoints 537a,
539a, wherein a distance D, extends between midpoints 537a, 539a.
Distal connecting element 512 similarly may have a bushing bore
530b, and first and second drill guide bores 532b, 534b with
respective midpoints 537b, 539b. Midpoints 537b, 539b may have a
distance D.sub.2 between them. Distal connecting element 512 may
also have a fin bore 536 located near the bushing bore 530b. Fin
bore 536 may receive at least a portion of a fin 514, as discussed
above.
[0092] Bushing bores 530a, 530b may receive at least a portion of a
bushing 450. Likewise, first and second drill guide bores 532a,
534a, 532b, 534b may receive at least a portion of a first and
second drill guide 502, 504, respectively. Generally, the proximal
connecting element 510 may be situated near the proximal ends 506,
508 of first and second drill guide 502, 504, and the distal
connecting element 512 may be situated near the distal ends 516,
518 of the first and second drill guides 502, 504. While the
embodiment in FIGS. 12A-12B show two connecting elements, 502, 504,
it contemplated that only one connecting element could be used, or
that more than two connecting elements could be utilized with a
single assembly 500.
[0093] The placement of the bores in the connecting elements 510,
512 may determine the angles and arrangements of which the bushing
450 and first and second drill guides 502, 504 are situated in
relation to one another. For instance, the embodiment shown in
FIGS. 12A-13B utilizes proximal connecting element 510 with
distance D.sub.1 larger than the distance D.sub.2 of the distal
connecting element 512. The result of this arrangement is, as
bushing 450 and first and second drill guides 502, 504 are
generally linear, that the bushing and drill guides are generally
convergent from the proximal end of the assembly to the distal end
of the assembly 500. However, it is contemplated that D.sub.1 and
D.sub.2 could be substantially equal, thereby creating an
arrangement where the bushing and drill guides would be
substantially parallel. Moreover, D.sub.2 may be greater than
D.sub.1, thereby creating a divergent relationship between the
bushing and/or drill guides from the proximal to the distal end of
the assembly 500. Generally, both D.sub.1 and D.sub.2 may be from
about 5 mm to about 35 mm. The sizes of the bores of each
connecting element 510, 512 may generally fit a desired engagement
portion of a bushing and/or drill guide.
[0094] Those skilled in the art will recognize that bushing 200,
450 may be configured and dimensioned to fit bone plate fastener
holes and/or drill recesses with shapes other than circular. For
example, bushing 200, 450 may be adapted to fit elliptical,
hexagonal, star-shaped, or square fastener holes and/or drill
recesses.
[0095] Preferably, the components of surgical drill-guide assembly
5, 500 are metallic, passivated, and electropolished. Most
preferably, the components are formed of stainless steel, except
for the springs which are formed of spring steel, although other
materials may be used. Preferably, at least the handle member is
forged, while the other components may be machined, and the
surgical drill-guide assembly preferably has a matte finish so that
the surfaces of the components do not reflect operating room light
in such a manner as to distract the surgeon or user. Some
components may be subjected to heat treatments so that the surfaces
are work hardened. The surfaces are preferably burr-free.
Preferably, the surface finish allows individual components to move
with respect to each other in a smooth and non-binding fashion
through each component's entire range of motion. Additionally, all
pins and fasteners are preferably flush with the surfaces into
which they are fixed.
[0096] The present invention also involves several methods of
drilling holes. In one embodiment, a surgeon or user may insert the
bushing of a surgical drill-guide assembly into a fastener hole of
a bone-plate and may depress the ratchet-gear mechanism to slide
the alignment drill-barrel forward, expanding the bushing
preferably by the conical portions of the alignment drill-barrel
radially spreading the fingers in the bushing. The surgeon or user
may then lock the bushing to the plate by locking the alignment
drill-barrel and the bushing in fixed relation to each other, which
thereby may relieve the surgeon or user of the need to squeeze the
ratchet-gear mechanism toward the handle (see FIG. 11). The surgeon
or user may align the surgical drill-bit along the drilling axis
defined through the center of the bore in the alignment
drill-barrel and inserts the drill-bit in the barrel. The surgeon
or user then may drill a first hole coaxial with the central axis
of a first fastener hole in the plate. The drill-bit may be stopped
at a predetermined distance to provide a hole of predetermined
depth. The drill-bit may be removed from the alignment
drill-barrel. The bushing may thereafter be unlocked from the plate
by pressing the release knob, which may release the bushing from
the fastener hole so that the user can then freely and unfetteredly
remove the drill-guide assembly from the plate.
[0097] In another embodiment of use, a surgeon or user may insert
the bushing of a surgical drill-guide assembly into a shaped area
drill recess of a bone-plate and may depress the ratchet-gear
mechanism to slide the alignment drill-barrel forward, expanding
the bushing preferably by the conical portions of the alignment
drill-barrel radially spreading the fingers in the bushing. The fin
of the assembly may concurrently engage the slot of the recess. The
surgeon or user may then lock the bushing to the plate by locking
the alignment drill-barrel and the bushing in fixed relation to
each other, which thereby may relieve the surgeon or user of the
need to squeeze the ratchet-gear mechanism toward the handle (see
FIG. 11). The surgeon or user may align the surgical drill-bit
along the drilling axis defined through the centers of the bores of
the first and/or second drill guides and may insert the drill-bit
into the bores as desired.
[0098] While the invention has been shown and described herein with
reference to particular embodiments, it is to be understood that
the various additions, substitutions, or modifications of form,
structure, arrangement, proportions, materials, and components and
otherwise, used in the practice of the invention and which are
particularly adapted to specific environments and operative
requirements, may be made to the described embodiments without
departing from the spirit and scope of the present invention. For
example, the surgical drill-guide assembly may have alignment
drill-barrel that can be angulated in the cephalad/caudal or
sagittal planes, thereby permitting a range of angles to be chosen
for the holes to be drilled and further permitting a range of
spacings of plate holes to be accommodated. Moreover, alignment
drill-barrel that is removeably attachable to the base may be
provided so that a surgeon or user may select alignment
drill-barrel with holes that precisely accommodate a desired
drill-bit size. In addition, the drill-guide assembly handle may
include a grip that generally follows the contours of fingers that
hold the grip. The presently disclosed embodiments are therefore to
be considered in all respects as illustrative and not restrictive,
the scope of the invention being indicated by the appended claims,
and not limited to the foregoing description.
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