U.S. patent application number 12/608333 was filed with the patent office on 2010-05-06 for systems and methods for delivering bone cement to a bone anchor.
Invention is credited to Mark Hall, Bryan Jones, Kevin Fun Lee, Michael Michielli.
Application Number | 20100114174 12/608333 |
Document ID | / |
Family ID | 42129275 |
Filed Date | 2010-05-06 |
United States Patent
Application |
20100114174 |
Kind Code |
A1 |
Jones; Bryan ; et
al. |
May 6, 2010 |
Systems and Methods for Delivering Bone Cement to a Bone Anchor
Abstract
A system for delivering bone cement to a bone anchor includes an
anchor connection instrument for releasably connecting to a
proximal end of the bone anchor. The anchor connection instrument
includes a first member coupled to an opposed second member. The
first member and the second member have a distal end configured to
releasably connect to the proximal end of the bone anchor. The
first member is movable between a release position to facilitate
release of the anchor connection instrument from the proximal end
of the bone anchor and a connect position in which the first member
and the second member connect to the proximal end of the bone
anchor. A cement delivery tube is positionable in the passage
between the first member and the second member of the anchor
connection instrument. A bone cement delivery system is coupled to
the tube.
Inventors: |
Jones; Bryan; (West Roxbury,
MA) ; Michielli; Michael; (Raynham, MA) ;
Hall; Mark; (Raynham, MA) ; Lee; Kevin Fun;
(Raynham, MA) |
Correspondence
Address: |
PHILIP S. JOHNSON;JOHNSON & JOHNSON
ONE JOHNSON & JOHNSON PLAZA
NEW BRUNSWICK
NJ
08933-7003
US
|
Family ID: |
42129275 |
Appl. No.: |
12/608333 |
Filed: |
October 29, 2009 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61109661 |
Oct 30, 2008 |
|
|
|
Current U.S.
Class: |
606/279 ;
606/304; 606/93 |
Current CPC
Class: |
A61B 17/8816 20130101;
A61B 17/7032 20130101; A61B 2017/0023 20130101; A61B 17/7076
20130101; A61B 17/8822 20130101; A61B 17/7086 20130101; A61B 17/864
20130101; A61B 17/7098 20130101; A61B 17/8805 20130101; A61B
17/7085 20130101 |
Class at
Publication: |
606/279 ; 606/93;
606/304 |
International
Class: |
A61B 17/88 20060101
A61B017/88; A61B 17/58 20060101 A61B017/58; A61B 17/86 20060101
A61B017/86 |
Claims
1. An instrument system for delivering bone cement to a bone
anchor, the system comprising: an anchor connection instrument for
releasably connecting to a proximal end of the bone anchor, the
anchor connection instrument including a first member coupled to an
opposed second member, at least one of the first member and the
second member having a distal end configured to releasably connect
to the proximal end of the bone anchor, the first member being
movable between a release position to facilitate release of the
anchor connection instrument from the proximal end of the bone
anchor and a connect position in which at least one of the first
member and the second member connect to the proximal end of the
bone anchor, the first member and the second member defining a
passage therebetween; a cement delivery tube positionable in the
passage between the first member and the second member of the
anchor connection instrument, and a bone cement delivery system
coupled to the tube.
2. The instrument of claim 1, further comprising a tube connector
positioned within the passage between the first member and the
second member of the anchor connection mechanism for connecting the
tube to the anchor connection instrument, the tube connector having
an opening sized to receive the tube therethrough, the opening
sized to permit the tube to move along a longitudinal axis of the
tube and sized to restrict motion of the tube in a direction
transverse to the tube.
3. The instrument of claim 2, wherein the tube connector is
constructed of a polymer material.
4. The instrument of claim 1, wherein the first member is biased to
the connect position.
5. The instrument of claim 1, wherein the first member and the
second member are pivotally connected and pivot about a pivot axis,
the first member and the second member being pivotable between the
release position and the connect position.
6. The instrument of claim 5, wherein the first member and the
second member each include a proximal handle, manipulation of the
proximal handle effecting pivoting of the first member and the
second member.
7. The instrument of claim 5, wherein the first member and the
second member pivot apart from one another when pivoted to the
release position and pivot toward one another when pivoted to the
connect position.
8. The instrument of claim 7, wherein the distal end of the first
member is configured to engage an exterior of the proximal end of
the bone anchor.
9. The instrument of claim 8, wherein the distal end of the first
member has a projection for engaging an opening provided on the
exterior of the proximal end of the bone anchor.
10. The instrument of claim 5, wherein the first member and the
second member pivot toward one another when pivoted to the release
position and pivot away from another when pivoted to the connect
position.
11. The instrument of claim 10, wherein the distal end of the first
member is configured to engage an interior of the proximal end of
the bone anchor.
12. The instrument of claim 11, wherein the distal end of the first
member has a projection for engaging an internal thread provided on
the interior of the proximal end of the bone anchor.
13. The instrument of claim 1, wherein the first member moves apart
from the second member when moved to the release position and moves
toward the second member when moved to the connect position and the
distal end of the first member is configured to engage an exterior
of the proximal end of the bone anchor.
14. The instrument of claim 1, wherein the first member moves
towards the second member when moved to the release position and
moves away from the second member when moved to the connect
position and the distal end of the first member is configured to
engage an interior of the proximal end of the bone anchor.
15. The instrument system of claim 1, further comprising a valve
for selectively interrupting cement delivery through the tube.
16. The instrument system of claim 15, wherein the valve is
positioned proximate a distal end of the tube.
17. The instrument system of claim 15, wherein the valve is
positioned proximate a proximal end of the tube.
18. A bone anchor system comprising: a plurality of bone anchors,
each of the plurality of bone anchors including a proximal end, a
distal bone engaging end, a passage extending from an opening at
the proximal end to the distal bone engaging end, and an opening in
a sidewall of the distal bone engaging end, the opening
communicating with the passage, a bone cement delivery system, a
tube connectable to the bone cement delivery system, the tube being
sized to fit within the passage of each of the plurality of bone
anchors, an anchor connection instrument for releasably connecting
to a proximal end of the bone anchor, the anchor connection
instrument including a first member coupled to an opposed second
member, at least one of the first member and the second member
having a distal end configured to releasably connect to the
proximal end of the bone anchor, the first member being movable
between a release position to facilitate release of the anchor
connection instrument from the proximal end of the bone anchor and
a connect position in which at least one of the first member and
the second member connect to the proximal end of the bone anchor,
the first member and the second member defining a passage
therebetween; a tube connector positionable within the passage
between the first member and the second member of the anchor
connection mechanism for connecting the tube to the anchor
connection instrument, the tube connector have an opening sized to
receive the tube therethrough, the opening sized to permit the tube
to move along a longitudinal axis of the tube and sized to restrict
motion of the tube in a direction transverse to the tube.
19. The system of claim 18 further comprising a plurality of anchor
connection instruments, each of the anchor connection instruments
releasably connectable to the proximal end of one of the plurality
of bone anchors and having a passage for receiving the tube.
20. The system of claim 18, wherein the bone anchors are polyaxial
spinal screws, the polyaxial spinal screws having a proximal head
configured to receive a spinal rod and a distal bone engaging
portion having a screw thread, the distal bone engaging portion
being connected to the proximal head and positionable in a
plurality of orientations relative to the proximal head.
21. A method of delivering cement to a bone anchor anchored in a
bone of a patient, the method comprising moving the distal end of a
first member of an anchor connection instrument relative to the
distal end of a second member of the anchor connection instrument
to separate the distal end of the first member from the distal end
of the second member, positioning the distal end of the first
member and the distal end of the second member about the proximal
end of a bone anchor, moving the distal end of a first member
relative to the distal end of a second member to move the distal
end of the first member toward the distal end of the second member
and into contact with the proximal end of bone anchor thereby
connecting the anchor instrument to the proximal end of the bone
anchor, advancing a tube through the first member and the second
member, positioning a distal end of the tube into a passage of a
bone engaging portion of the bone anchor, connecting the tube to a
bone cement delivery system, and injecting cement into the passage
of the bone anchor through the tube.
22. The method of claim 21, further comprising removing the anchor
connecting instrument and the tube from the bone anchor, connecting
the anchor connecting instrument the tube to a second bone anchor,
and injecting cement into the second bone anchor through the
tube.
23. The method of claim 22, further comprising closing a valve
associated with the tube to interrupt cement flow to the tube prior
to removing the tube from the bone anchor, and opening the valve
prior to injecting cement into the second bone anchor.
24. The method of claim 23, wherein the valve is positioned
proximate the distal end of the tube.
25. The method of claim 24, wherein the valve is positioned
proximate the proximal end of the tube.
26. The method of claim 21, wherein at least a portion the bone
cement delivery system is positioned outside of a fluoroscopic
imaging field about the patient.
27. The method of claim 21, wherein the bone anchor includes one or
more openings in a sidewall of the bone anchor, the openings
communicating with the passage to allow bone cement to be dispensed
through one or more of the openings, and further comprising
adjusting the position of the distal end of the tube within the
passage of the bone anchor relative to one or more openings to
select the opening through which to dispense bone cement.
28. A spinal anchor system comprising: a plurality of spinal
anchors, each of the plurality of spinal anchors including a
proximal portion having a slot for receiving a rod, a distal bone
engaging portion, a passage extending from an opening in the
proximal portion to the distal bone engaging portion, and an
opening in a sidewall of the distal bone engaging portion, the
opening communicating with the passage, the proximal portion of the
spinal anchors including threads for receiving a closure mechanism
for securing the rod in the slot, a bone cement delivery system,
and a tube having a proximal end connectable to the bone cement
delivery system and a distal end sized to be positioned within the
passage of the distal bone engaging portion of a spine anchor of
the plurality of spine anchors, the tube having a connection member
positioned between the proximal end and the distal end of the tube
a distance from the distal end of the tube selected to allow the
distal end of the tube to be advance into the passage of the distal
bone engaging portion of a bone anchor, the connection member
having a thread configured to engage the thread on the proximal
portion of a spinal anchor of the plurality of spinal anchors.
29. The spinal anchor system of claim 28, wherein the plurality of
spinal anchors are polyaxial spinal screws in which the proximal
portion of a spinal anchor is adjustable relative to the distal
bone engaging portion.
30. The spinal anchor system of claim 28, wherein the thread of the
connection member is interrupted at two spaced apart, opposed
unthreaded sections.
31. The spinal anchor system of claim 30, wherein the connection
member is generally disk shaped and the unthreaded sections are
diametrically opposed to one another and are separated by a
threaded section.
32. A method of delivering cement to a spinal anchor anchored in a
vertebra of a patient, the method comprising: advancing a distal
end of a bone cement delivery tube through an opening in a proximal
portion of a spinal anchor, the proximal portion of the spinal
anchor having a slot for receiving a spinal rod and a thread for
receiving a closure mechanism for securing the rod in the proximal
portion, advancing the distal end of the bone cement delivery tube
into a passage formed in the distal bone engaging portion of the
spinal anchor, the passage communicating with the opening in the
proximal portion of the spinal anchor, engaging a thread on a
connection mechanism on the bone cement delivery tube with the
thread on the proximal portion of the spinal anchor, the connection
member positioned between the proximal end and the distal end of
the bone cement delivery tube a distance from the distal end of the
bone cement delivery tube selected to allow the distal end of the
bone cement delivery tube to be advance into the passage of the
distal bone engaging portion of a bone anchor, rotating the
connection member to secure the connection member and the bone
cement delivery tube to the proximal portion of the spinal anchor,
connecting a proximal end of the bone cement delivery tube to a
bone cement delivery system, and injecting cement into the passage
of distal bone engaging portion of the spinal anchor through the
bone cement delivery tube.
33. The method of claim 32, wherein at least a portion the bone
cement delivery system is positioned outside of a fluoroscopic
imaging field about the patient.
34. The method of claim 32, further comprising removing the
connection member and the tube from the spinal anchor, advancing a
distal end of a bone cement delivery tube through an opening in a
proximal portion of a second spinal anchor, advancing the distal
end of the bone cement delivery tube into a passage formed in the
distal bone engaging portion of the second spinal anchor, engaging
a thread on a connection mechanism on the bone cement delivery tube
with a thread on the proximal portion of the second spinal anchor,
rotating the connection member to secure the connection member and
the bone cement delivery tube to the proximal portion of the second
spinal anchor, and injecting cement into the passage of distal bone
engaging portion of the spinal anchor through the bone cement
delivery tube.
35. The method of claim 32, wherein the thread of the connection
member is interrupted at two spaced apart, opposed unthreaded
sections and further comprising inserting the connection member
into the proximal portion of the bone anchor with the unthread
sections facing the thread, and rotating the connection member to
engage the thread on the connection member with the thread on the
proximal portion of the bone anchor.
36. A method of stabilizing a first vertebra and a second vertebra
of a patient, the method comprising: implanting a first bone anchor
into the first vertebra, the first bone anchor having a proximal
portion for engaging a spinal rod and a distal bone engaging
portion, implanting a second bone anchor into the second vertebra,
the second bone anchor having a proximal portion for engaging a
spinal rod and a distal bone engaging portion, connecting an anchor
connection instrument to the proximal portion of the first bone
anchor, positioning the distal end of a cement delivery tube into a
passage provided through at least a portion of the bone engaging
portion of the first bone anchor, the anchor connection instrument
connecting the cement delivery tube to the first bone anchor,
delivering bone cement from a bone cement delivery system coupled
to the bone cement delivery tube through the passage in the first
bone anchor to the first vertebra, removing the anchor connection
instrument and the cement delivery tube from the first bone anchor,
connecting the anchor connection instrument and the cement delivery
tube to the second bone anchor, delivering bone cement from the
bone cement delivery system coupled to the bone cement delivery
tube through a passage in bone engaging portion of the second bone
anchor to the second vertebra, and connecting a spinal connection
element to the first bone anchor and the second bone anchor.
37. The method of claim 36, wherein at least a portion the bone
cement delivery system is positioned outside of a fluoroscopic
imaging field about the patient.
38. The method of claim 36, further comprising closing a valve
associated with the cement delivery tube to interrupt cement flow
to the cement delivery tube prior to removing the tube from the
bone anchor, and opening the valve prior to injecting cement into
the second bone anchor.
39. The method of claim 38, wherein the valve is positioned
proximate the distal end of the cement delivery tube.
40. The method of claim 38, wherein the valve is positioned
proximate the proximal end of the tube.
41. The method of claim 36, wherein the first bone anchor and the
second bone anchor are at least one of a polyaxial screw, a
monoaxial screw, or a uniplanar screw.
42. The method of claim 36, wherein the cement delivery system
includes a pump for advancing the bone cement through the cement
delivery tube.
43. The method of claim 42, wherein the pump is positioned outside
of a fluoroscopic imaging field about the patient.
44. The method of claim 42, further comprising reversing operation
of the pump to reduce pressure on the bone cement in the cement
delivery tube prior to removing the anchor connection instrument
and the cement delivery tube from the first bone anchor.
45. A method of stabilizing a first vertebra and a second vertebra
of a patient, the method comprising: implanting a first bone anchor
into the first vertebra, the first bone anchor having a proximal
portion for engaging a spinal rod and a distal bone engaging
portion, implanting a second bone anchor into the second vertebra,
the second bone anchor having a proximal portion for engaging a
spinal rod and a distal bone engaging portion, connecting a first
anchor connection instrument to the proximal portion of the first
bone anchor, connecting a second anchor connection instrument to
the proximal portion of the second bone anchor, positioning a
distal end of a cement delivery tube into a passage provided
through at least a portion of the bone engaging portion of the
first bone anchor, the first anchor connection instrument
connecting the cement delivery tube to the first bone anchor,
delivering bone cement from a bone cement delivery system coupled
to the bone cement delivery tube through the passage in the first
bone anchor to the first vertebra, removing the cement delivery
tube from the first anchor connection instrument and the first bone
anchor, connecting the cement delivery tube to second anchor
connecting instrument connected to the second bone anchor,
delivering bone cement from the bone cement delivery system coupled
to the bone cement delivery tube through a passage in bone engaging
portion of the second bone anchor to the second vertebra, and
connecting a spinal connection element to the first bone anchor and
the second bone anchor.
46. The method of claim 45, wherein at least a portion the bone
cement delivery system is positioned outside of a fluoroscopic
imaging field about the patient.
47. The method of claim 45, further comprising closing a valve
associated with the cement delivery tube to interrupt cement flow
to the cement delivery tube prior to removing the tube from the
bone anchor, and opening the valve prior to injecting cement into
the second bone anchor.
48. The method of claim 47, wherein the valve is positioned
proximate the distal end of the cement delivery tube.
49. The method of claim 47, wherein the valve is positioned
proximate the proximal end of the tube.
50. The method of claim 45, wherein the first bone anchor and the
second bone anchor are at least one of a polyaxial screw, a
monoaxial screw, or a uniplanar screw.
51. The method of claim 45, wherein the cement delivery system
includes a pump for advancing the bone cement through the cement
delivery tube.
52. The method of claim 51, wherein the pump is positioned outside
of a fluoroscopic imaging field about the patient.
53. The method of claim 52, further comprising reversing operation
of the pump to reduce pressure on the bone cement in the cement
delivery tube prior to removing the anchor connection instrument
and the cement delivery tube from the first bone anchor.
54. The method of claim 45, wherein the cement delivery tube is
connected to the first anchor connection instrument during
connection of the first anchor connection instrument to the
proximal portion of the first bone anchor.
55. The method of claim 45, wherein the cement delivery tube is
connected to the first anchor connection instrument after
connection of the first anchor connection instrument to the
proximal portion of the first bone anchor.
56. The method of claim 45, wherein the distal end of the cement
delivery tube includes an occlusion for blocking cement flow
through a portion of the passage in the first bone anchor and the
passage of the second bone anchor.
57. The method of claim 56, wherein the distal end of the cement
delivery tube includes one or more slots positioned proximal to the
occlusion for delivering cement to the passage in the first bone
anchor and the passage of the second bone anchor.
58. The method of claim 56, wherein the occlusion is spaced apart
from the distal end of the cement delivery tube by a wire.
59. The method of claim 45, wherein the distal end of the cement
delivery tube includes a first lengthwise section and a second
lengthwise section distal to the first lengthwise section, the
first lengthwise section has increased flexibility compared to the
first lengthwise section.
60. An instrument system for delivering bone cement to a bone
anchor, the system comprising: an anchor connection instrument for
releasably connecting to a proximal end of the bone anchor, the
anchor connection instrument including an instrument body and a
first member movably coupled to the instrument body, the instrument
body having a proximal end, a distal end and a passage
therebetween, the distal end sized and shaped to be positioned with
the proximal end of the bone anchor, the first member configured to
releasably connect to the proximal end of the bone anchor, the
first member being movable relative to the instrument body between
a release position to facilitate release of the anchor connection
instrument from the proximal end of the bone anchor and a connect
position in which the first member connects to the proximal end of
the bone anchor, a cement delivery tube positionable in the passage
of the instrument body of the anchor connection instrument, and a
bone cement delivery system coupled to the tube.
61. The instrument of claim 60, wherein the first member is
configured to connect to the interior of the proximal end of the
bone anchor.
62. The instrument of claim 61, wherein the first member is a prong
having a distal free end and a proximal end connected to the
instrument body, the free end moving toward the instrument body in
the release position and the free end moving away from the
instrument body in the connect position.
63. The instrument of claim 60, wherein the first member is
configured to connect to the exterior of the proximal end of the
bone anchor.
64. The instrument of claim 63, wherein the first member is
pivotally connected to the instrument body, the first member having
a proximal handle and a distal end, the distal end moving away from
the instrument body in the release position and the distal end
moving toward the instrument body in the connect position.
65. The instrument of claim 60, wherein a distal end of the cement
delivery tube includes an occlusion for blocking cement flow
through a portion of a passage in a bone engaging portion of the
bone anchor.
66. The instrument of claim 65, wherein the distal end of the
cement delivery tube includes one or more slots positioned proximal
to the occlusion for delivering cement to the passage in the bone
engaging portion of the bone anchor.
67. The instrument of claim 65, wherein the occlusion is spaced
apart from the distal end of the cement delivery tube by a
wire.
68. The instrument of claim 60, wherein a distal end of the cement
delivery tube includes a first lengthwise section and a second
lengthwise section distal to the first lengthwise section, the
first lengthwise section has increased flexibility compared to the
first lengthwise section.
69. The instrument of claim 60, wherein the distal end of the
instrument body comprises a connection member positioned with the
passage and longitudinally adjustable relative to the instrument
body between an extended position and a retracted position.
70. The instrument of claim 69 wherein the instrument body includes
a spring that biases the instrument body to the extended
position.
71. The instrument of claim 69, wherein the connection member
includes a cylindrical body and an enlarged distal end having an
arcuate distal surface.
72. A spinal anchor system comprising: a plurality of spinal
anchors, each of the plurality of spinal anchors including a
proximal portion having a slot for receiving a rod, a distal bone
engaging portion, a passage extending from an opening in the
proximal portion to the distal bone engaging portion, and an
opening in a sidewall of the distal bone engaging portion, the
opening communicating with the passage, the proximal portion of the
spinal anchors including threads for receiving a closure mechanism
for securing the rod in the slot, a screw extension connectable to
one of the plurality of bone anchors, a bone cement delivery
system, a cement delivery tube having a proximal end connectable to
the bone cement delivery system and a distal end sized to be
positioned within the passage of the distal bone engaging portion
of a spine anchor of the plurality of spine anchors, and an anchor
connection instrument having an instrument body having a proximal
end, a distal end, and a passage therebetween for receiving the
cement delivery tube, the distal end of the anchor connection
instrument including a first connection feature configure to
connect to the proximal portion of one of the bone anchors and a
second connection feature configured to connect to the distal bone
engaging portion of the bone anchor.
73. The system of claim 72, wherein the first connection feature of
the anchor connection instrument comprises an externally threaded
section for threadingly engaging an internal thread provided on the
proximal portion of the bone anchor.
74. The system of claim 73, wherein the second connection feature
of the anchor connection instrument comprises a drive tip for
engaging a drive feature on a proximal end of the bone engaging
portion of the bone anchor.
Description
REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority to U.S. Provisional
Patent Application No. 61/109,661, filed Oct. 30, 2008, which is
incorporated herein by reference.
BACKGROUND
[0002] Bone anchors may be used in orthopedic surgery to
temporarily fix bone during the healing or fusion process. One
problem with the use of bone anchors is that bone anchors may
pullout or otherwise be displaced from the bone prior to the
healing or fusion process completing. This problem is particularly
common when a bone anchor is positioned in poor quality bone such
as osteoporotic bone. Accordingly, there is need for improved
instruments and techniques for securing bone anchors to bone that
minimize instances of anchor pull out.
SUMMARY
[0003] Disclosed herein are systems and methods for delivering bone
cement or other materials to one or more bone anchors, such as one
or more spinal anchors. In accordance with one aspect, an
instrument system for delivering bone cement to a bone anchor may
comprise an anchor connection instrument for releasably connecting
to a proximal end of the bone anchor. The anchor connection
instrument may include a first member coupled to an opposed second
member. The first member and/or the second member may have a distal
end configured to releasably connect to the proximal end of the
bone anchor. The first member is movable between a release position
to facilitate release of the anchor connection instrument from the
proximal end of the bone anchor and a connect position in which at
least one of the first member and the second member is connected to
the proximal end of the bone anchor. The first member and the
second member define a passage therebetween. The system includes a
cement delivery tube positionable in the passage between the first
member and the second member of the anchor connection instrument
and a bone cement delivery system coupled to the tube.
[0004] In accordance with another aspect, a bone anchor system may
include a plurality of bone anchors, each of the plurality of bone
anchors including a proximal end, a distal bone engaging end, a
passage extending from an opening at the proximal end to the distal
bone engaging end, and an opening in a sidewall of the distal bone
engaging end that communicates with the passage. The bone anchor
system may include a bone cement delivery system and a tube
connectable to the bone cement delivery system, the tube being
sized to fit within the passage of each of the plurality of bone
anchors. The bone anchor system may include an anchor connection
instrument for releasably connecting to a proximal end of one of
the plurality of bone anchors, the anchor connecting instrument
including a first member pivotally coupled to an opposed second
member. At least one of the first member and the second member may
have a distal end configured to releasably connect to an exterior
of the proximal end of one of the bone anchors. The first member
and the second member may be pivotable between a spaced apart first
position to facilitate release of the anchor connection instrument
from the proximal end of one of the bone anchors and a second
position in which the first member and the second member connect to
the proximal end of one of the plurality of bone anchors. The bone
anchor system may include a tube connector positionable within a
passage provided between the first member and the second member of
the anchor connecting mechanism for connecting the tube to the
anchor connection instrument. The tube connector may have an
opening sized to receive the tube therethrough that may be sized to
permit the tube to move along a longitudinal axis of the tube and
may be sized to restrict motion of the tube in a direction
transverse to the tube.
[0005] In accordance with another aspect, a method of stabilizing a
first vertebra and a second vertebra of a patient may comprise
implanting a first bone anchor into the first vertebra, the first
bone anchor having a proximal portion for engaging a spinal rod and
a distal bone engaging portion. The method further comprises
implanting a second bone anchor into the second vertebra, the
second bone anchor having a proximal portion for engaging a spinal
rod and a distal bone engaging portion. The method further
comprises connecting an anchor connection instrument to the
proximal portion of the first bone anchor and positioning the
distal end of a cement delivery tube into a passage provided
through at least a portion of the bone engaging portion of the
first bone anchor, the anchor connection instrument connecting the
cement delivery tube to the first bone anchor. The method further
comprises delivering bone cement from a bone cement delivery system
coupled to the bone cement delivery tube through the passage in the
first bone anchor to the first vertebra, removing the anchor
connection instrument and the cement delivery tube from the first
bone anchor, connecting the anchor connection instrument and the
cement delivery tube to the second bone anchor, delivering bone
cement from the bone cement delivery system coupled to the bone
cement delivery tube through a passage in bone engaging portion of
the second bone anchor to the second vertebra, and connecting a
spinal connection element to the first bone anchor and the second
bone anchor.
BRIEF DESCRIPTION OF THE FIGURES
[0006] These and other features and advantages of the systems and
methods disclosed herein will be more fully understood by reference
to the following detailed description in conjunction with the
attached drawings in which like reference numerals refer to like
elements through the different views. The drawings illustrate
principles of the systems and methods disclosed herein and,
although not to scale, show relative dimensions.
[0007] FIG. 1 is a perspective view of an exemplary system for
delivering bone cement to a bone anchor, illustrating the system
connected to a bone anchor;
[0008] FIG. 2 is a perspective view of the system of FIG. 1,
illustrating the anchor connection instrument and the cement
delivery tube prior to connection to the bone anchor;
[0009] FIG. 3 is a perspective view of the system of FIG. 1,
illustrating the bone cement delivery tube inserted into the
passage of the bone anchor;
[0010] FIG. 4 is a perspective view of the system of FIG. 1,
illustrating the distal end of the anchor connection instrument
connected to the bone anchor;
[0011] FIG. 5 is a side view in cross section of the system of FIG.
1, illustrating the anchor connection instrument connected to the
bone anchor;
[0012] FIG. 6 is a side view in cross section of the system of FIG.
1, illustrating the anchor connection instrument connected to the
bone anchor and the cement delivery tube positioned with the
passage of the bone anchor;
[0013] FIGS. 7A-7D are perspective views of another exemplary
system for delivering bone cement to a bone anchor, illustrating
the connection of the system to a bone anchor;
[0014] FIGS. 8A-E are perspective views of another exemplary system
for delivering bone cement to a bone anchor, illustrating the
connection of the system to a bone anchor;
[0015] FIG. 9 is a perspective view of the system of FIGS.
8A-8E;
[0016] FIG. 10 is a perspective view of the connection member of
the system of FIGS. 8A-8E;
[0017] FIGS. 11A-11B are perspective views of another exemplary
system for delivering bone cement to a bone anchor, illustrating
the connection of the system to a bone anchor;
[0018] FIGS. 12A-12C are perspective views of another exemplary
system for delivering bone cement to a bone anchor, illustrating
the connection of the system to a bone anchor;
[0019] FIGS. 13A-F are perspective views of another exemplary
system for delivering bone cement to a bone anchor, illustrating
the connection of the system to a bone anchor;
[0020] FIG. 14 is a side view in cross section of the system of
FIGS. 13A-E, illustrating the anchor connection instrument
connected to the bone anchor 16;
[0021] FIG. 15 is a side view in cross section of the distal end of
the anchor connection instrument of FIG. 14;
[0022] FIGS. 16A-16B are side views in cross section of an
exemplary bone cement delivery tube including a valve at a distal
end thereof, illustrating the valve in an open and a closed
position;
[0023] FIG. 17A is an exploded view of another exemplary system for
delivering bone cement to a bone anchor, illustrating the anchor
connection instrument and the cement delivery tube of the system
and a bone anchor;
[0024] FIG. 17B is a front view of the system of FIG. 17A,
illustrating the anchor connection instrument and the cement
delivery tube of the system connected to the bone anchor;
[0025] FIG. 17C is a side view of the system of FIG. 17A,
illustrating the anchor connection instrument and the cement
delivery tube of the system connected to the bone anchor;
[0026] FIG. 17D is a side view in cross section of the system of
FIG. 17A, illustrating the anchor connection instrument and the
cement delivery tube of the system connected to the bone
anchor;
[0027] FIG. 17E is an exploded view of the anchor connection
instrument of the system of FIG. 17A;
[0028] FIG. 18A is an exploded view of another exemplary system for
delivering bone cement to a bone anchor, illustrating the anchor
connection instrument and the cement delivery tube of the system
and a bone anchor;
[0029] FIG. 18B is a front view of the system of FIG. 18A,
illustrating the anchor connection instrument and the cement
delivery tube of the system connected to the bone anchor;
[0030] FIG. 18C is a side view of the system of FIG. 18A,
illustrating the anchor connection instrument and the cement
delivery tube of the system connected to the bone anchor;
[0031] FIG. 18D is a side view in cross section of the system of
FIG. 18A, illustrating the anchor connection instrument and the
cement delivery tube of the system connected to the bone
anchor;
[0032] FIG. 18E is an exploded view of the anchor connection
instrument of the system of FIG. 18A;
[0033] FIG. 19A is an exploded view of another exemplary system for
delivering bone cement to a bone anchor, illustrating the anchor
connection instrument and the cement delivery tube of the system
and a screw extension and a bone anchor;
[0034] FIG. 19B is a side view of the system of FIG. 19A,
illustrating the anchor connection instrument and the cement
delivery tube of the system connected to the screw extension and
the bone anchor;
[0035] FIG. 19C is a side view in cross section of the system of
FIG. 19A, illustrating the anchor connection instrument and the
cement delivery tube of the system connected to the screw extension
and the bone anchor;
[0036] FIG. 19D is side view of the anchor connection instrument of
the system of FIG. 19A;
[0037] FIG. 19E is side view of the cement delivery tube of the
system of FIG. 19A;
[0038] FIG. 20A is an exploded view of another exemplary system for
delivering bone cement to a bone anchor, illustrating the anchor
connection instrument, the cement delivery tube, and the
counter-torque instrument of the system and a bone anchor;
[0039] FIG. 20B is a side view of the system of FIG. 20A,
illustrating the anchor connection instrument, the cement delivery
tube, and the counter-torque instrument of the system connected to
the bone anchor;
[0040] FIG. 20C is a side view in cross section of the system of
FIG. 20A, illustrating the anchor connection instrument, the cement
delivery tube, and the counter-torque instrument of the system
connected to the bone anchor;
[0041] FIG. 20D is front view of the counter-torque instrument of
the system of FIG. 20A;
[0042] FIG. 20E is side view of the counter-instrument of the
system of FIG. 20A;
[0043] FIG. 21 is an exploded view of another exemplary system for
delivering bone cement to a bone anchor, illustrating the anchor
connection instrument, the cement delivery tube, and a
counter-torque instrument of the system and a bone anchor;
[0044] FIG. 22A is a front view of another exemplary embodiment of
a cement delivery tube, illustrating the distal end of the
tube;
[0045] FIG. 22B is a side view in cross section of the distal end
of the tube of FIG. 22A;
[0046] FIG. 22C is a side view of the distal end of the tube of
FIG. 22A;
[0047] FIG. 23 is a perspective view of another exemplary
embodiment of a cement delivery tube, illustrating the distal end
of the tube;
[0048] FIG. 24A is a side view in cross section of another
exemplary embodiment of a cement delivery tube; and
[0049] FIG. 24B is a side view in cross section of another
exemplary embodiment of a cement delivery tube.
DETAIL DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0050] Certain exemplary embodiments will now be described to
provide an overall understanding of the principles of the
structure, function, manufacture, and use of the instruments and
methods disclosed herein. One or more examples of these embodiments
are illustrated in the accompanying drawings. Those of ordinary
skill in the art will understand that the systems and methods
specifically described herein and illustrated in the accompanying
drawings are non-limiting exemplary embodiments and that the scope
of the present invention is defined solely by the claims. The
features illustrated or described in connection with one exemplary
embodiment may be combined with the features of other embodiments.
Such modifications and variations are intended to be included
within the scope of the present invention.
[0051] The articles "a" and "an" are used herein to refer to one or
to more than one (i.e. to at least one) of the grammatical object
of the article. By way of example, "an element" means one element
or more than one element.
[0052] The terms "comprise," "include," and "have," and the
derivatives thereof, are used herein interchangeably as
comprehensive, open-ended terms. For example, use of "comprising,"
"including," or "having" means that whatever element is comprised,
had, or included, is not the only element encompassed by the
subject of the clause that contains the verb.
[0053] FIGS. 1-6 illustrate an exemplary embodiment of a system for
delivering bone cement or other materials to a bone anchor. The
exemplary system 10 includes an anchor connection instrument 12, a
delivery tube 14 connected to the bone anchor 16 by the anchor
instrument 12, and a cement delivery system 18 coupled to the
cement delivery tube for supplying bone cement to the bone anchor
16. The exemplary system 10 facilitates rapid attachment and
removal of the system 10 from a bone anchor such that multiple bone
anchors may be provided with bone cement prior to the bone cement
setting. The system 10 may be used with any type of bone anchors,
including, for example, bone screws used in spine surgery to fix or
connect the vertebra of the spine. Such spinal bone screws may
include, for example, polyaxial bone screws, monoaxial bone screws,
and uniplanar bone screws.
[0054] Continuing to refer to FIGS. 1-6, the anchor connection
instrument 12 of the exemplary system 10 connects the delivery tube
14 to a bone anchor 16. The exemplary bone anchor 16 is a polyaxial
spinal anchor designed for posterior implantation in the pedicle or
lateral mass of a vertebra. The exemplary bone anchor 16 includes a
proximal portion 30 configured to receive a spinal connection
element such as a rigid or dynamic spinal rod and a distal portion
32 configured to engage bone. For example, the proximal portion 30
of the exemplary bone anchor includes a U-shaped rod-receiving slot
31 for receiving a spinal rod. The proximal portion 30 may be
configured to receive a closure mechanism, such as, for example, an
external nut or cap or an internal setscrew that engages an
internal thread 33 provided on the interior of the proximal portion
30 of the bone anchor 16. The proximal portion 30 of the bone
anchor 16 may also include features for engaging instruments such
as the anchor connection instrument 12. Such features may include
one or more openings, such as a slot or the like, for receiving a
complementary projection provided on an instrument. In the
exemplary bone anchor 16, the proximal portion 30 includes two
spaced apart, diametrically opposed slots 35.
[0055] The distal bone engaging portion 32 of the exemplary bone
anchor 16 includes one or more screw threads. The exemplary bone
anchor 16 is polyaxial, e.g., the proximal end portion 30 is
connected to the distal bone engaging portion 32 in a polyaxial
relationship such that the distal bone engaging portion 32 may be
positioned in a plurality of orientations relative to the proximal
end portion 30. Exemplary polyaxial spinal anchors include EXPEDIUM
polyaxial pedicle screws, VIPER polyaxial pedicle screws, MOSS
MIAMI and MOSS MIAMI SI polyaxial pedicle screws, and MOUNTAINEER
polyaxial pedicle screws, all of which are available from DePuy
Spine, Inc., of Raynham, Mass. Alternative exemplary spine screws
include DePuy Spine's EXPEDIUM monoaxial pedicle screws and
uniplanar pedicle screws. In addition, exemplary polyaxial pedicle
screws are described in U.S. Patent Application Publication Nos. US
2005/0131408 and US 2005/0228388, each of which is incorporated
herein by reference.
[0056] The exemplary bone anchor 16 is configured to permit bone
cement or other materials to be injected into bone through the bone
engaging portion 32. A passage 34 extends from the rod receiving
slot 31 in the proximal portion 30 of the bone anchor 16 into the
distal bone engaging portion 32. The distal bone engaging portion
32 includes one or more openings 36 in the sidewall of the distal
bone engaging portion 32. The openings 36 communicate with the
passage 34 and extend radially from the passage 34 through the
sidewall of the distal bone engaging portion 32. Bone cement or
other materials may be injected into bone through the passage 34
and the openings 36.
[0057] The anchor connection instrument may be configured to engage
a proximal portion 30 of the bone anchor 16 and may connect to an
exterior of the bone anchor or, in other embodiments, may connect
to the interior of the bone anchor. Exemplary anchor connection
instruments are described in US Patent Application Publication Nos.
US20050149036, US20050149053, US20060079909, and US20070260261,
each of which are incorporated herein by reference. In the
illustrated embodiment, the anchor connection instrument 12
connects to the exterior of the proximal portion 30 of the bone
anchor 16. The exemplary anchor connection instrument 16 includes a
first member 20A and second member 20B that cooperate to
selectively connect the instrument to the bone anchor 16. The first
member 20A and the second member 20B have distal ends 22A, 22B
configured to releasably connect the instrument 12 to the exterior
of the proximal portion 30 of the bone anchor 16. For example, the
distal ends 22A and 22B may include a projection 24A, 24B for
engaging a feature, such as slots 35, in the proximal portion 30 of
the bone anchor 16. Alternatively, the distal ends 22A, 22B may
include openings to receive a mating feature, such as a projection,
provided on the proximal portion of the bone anchor 16. Moreover,
in alternative embodiments, the distal end of only one of the
members may be configured to engage the bone anchor.
[0058] In the exemplary embodiment, the first member 20A is coupled
to the opposed second member 20B. The first member 20A and the
second member 20B are pivotally connected and pivot about a pivot
axis between a release position, in which the first member 20A and
the second pivot member 20B pivot away from one another to
facilitate removal of the distal ends 22A, 22B of the first member
20A and the second member 20B from the bone anchor and a connect
position in which the first member 20A and the second member 20B
pivot towards one another and the distal ends 22A, 22B can engage
the proximal portion 30 of the bone anchor 16. FIGS. 1-6 illustrate
the anchor connection instrument 12 in the connect position. The
first member 20A includes a proximal handle 26A and the second
member 20B includes a proximal handle 26B. Manipulation of the
proximal handles 26A, 26B can effect pivoting of the first member
20A and the second member 20B between the release position and the
connect position. For example, movement of the proximal handles 26A
and 26B towards one another, in the direction of arrows X in FIG.
3, causes the distal ends 22A, 22B away from one another, in the
direction of arrows Y in FIG. 3, to move toward the release
position. The first member 20A and the second member 20B may be
biased to the release position or to the connect position by a
spring or other biasing mechanism.
[0059] The anchor connection instrument 12 may be constructed of
any biocompatible material suitable for use in medical instruments
or implants. For example, the anchor construction instrument 12 may
be constructed from a metal, such as stainless steel, or a polymer,
such as Radel.RTM.. The anchor construction instrument 12 may be a
single use device or may be configured for multiple uses after
sterilization.
[0060] At least a portion of the first member 20A may be spaced
apart from the second member 20B to form a passage 28 therebetween
for receiving the cement delivery tube 14. A tube connector 40 may
be positioned within the passage 28 between the first member 20A
and the second member 20B, as illustrated in FIG. 5. The tube
connector 40 may have an opening sized to receive the cement
delivery tube 14 therethrough. The opening in the tube connector 40
is preferably sized to permit the cement delivery tube 14 to move
along a longitudinal axis of the tube 14 relative to the anchor
connection instrument 12 while concomitantly restricting motion of
the tube 14 in a direction transverse to the longitudinal axis of
the tube 14. For example, the opening in the tube connector 14 has
an extent, e.g., a diameter, approximate to the extent, e.g. the
outer diameter, of the cement delivery tube 14. In the exemplary
embodiment, the tube connector 40 is generally disk shaped, is
constructed of an elastomeric polymer material, and has a central
opening having a diameter less than or equal to the outer diameter
of the cement delivery tube 14.
[0061] The cement delivery tube 14 is removably coupled to a cement
delivery system 18. The cement delivery system 18 may include a
reservoir 50 or other container for holding and/or mixing the
cement and a pressure source 52, such as a pump, for applying
pressure to the bone cement in the reservoir 50 to move the bone
cement through the system 18, and the tube 14, relative to the
reservoir 50. A suitable cement delivery system 50 is the
CONFIDENCE spinal cement system, available from DePuy Spine, Inc.
of Raynham, Mass., and the cement delivery systems described in the
following U.S. patents and patent applications: U.S. Pat. No.
7,097,648 and U.S. Patent Application Publication Nos. U.S.
2008/0228192, U.S. 2006/0264967, U.S. 2006/0079905, U.S.
2007/0027230, U.S. 2008/0212405, U.S. 2007/0032567, and U.S.
2008/0200915 and U.S. patent application Ser. Nos. 09/890,172 and
11/561,969, each of which is incorporated herein by reference.
[0062] The bone cement delivery tube 14 is coupled to the bone
cement delivery system 18 to permit bone cement to be introduced to
the delivery tube 14 from the system 18. In the exemplary
embodiment, the bone cement delivery tube 14 is an elongated hollow
tube having a distal end 54 sized for insertion into the passage 34
in the distal portion 32 of the bone anchor 16 and a proximal end
56 having a handle 58 to facilitate manipulation of the tube 14.
The proximal end 56 of the tube may extend through the handle 58
and terminate at connection feature, such as a luer lock
connection, that permits connection to the bone cement delivery
system 18. The cement delivery tube 14 may be a needle or stylet
having a diameter less than the diameter of the passage 34 in the
distal portion 32 of the bone anchor 16. The cement delivery tube
14 may be constructed from any biocompatible material suitable for
use in medical instruments or implants. For example, the cement
delivery tube 14 may be constructed from a metal, such as stainless
steel, or a polymer, such as Radel.RTM.. The cement delivery tube
14 may be a single use device or may be configured for multiple
uses after sterilization. In one exemplary embodiment, the anchor
connection instrument 12, including the tube connector 40, and the
cement delivery tube 14, may be prepackaged in an assembled,
sterilized state with the cement delivery tube 14 positioned with
the anchor connection instrument 12 and through the tube connector
40.
[0063] In the exemplary embodiment, the reservoir 50 of the cement
delivery system 18 is directly connected to the cement delivery
tube 14 and the pressure source 52 may be positioned remote from
the cement reservoir 50 and the cement delivery tube 14. Remote
placement of the pressure source 52 permits a medical professional
to inject cement into the bone anchor 16 outside of the imaging
field of the imaging system (e.g., a fluoroscopy or x-ray system)
used to monitor the cement volume injected into the patient's bone
thorough the bone anchor. In this manner, the medical professional
is not exposed to radiation from the imaging system during the bone
cement injection procedure.
[0064] The cement delivery system 18 may include a valve 60 for
controlling cement delivery to the cement delivery tube 14. For
example, the valve 60 may be used to selectively interrupt flow of
bone cement to the bone cement delivery tube 14. In the exemplary
embodiment, the valve 60 is positioned at the interface between the
cement delivery system 18 and the tube 14, e.g., between the cement
reservoir 50 and the proximal end 56 of the cement delivery tube
14. In alternative embodiments, a valve may be provided as part of
the cement delivery tube 14, for example, in the handle 58 or at
the distal end 54 of the tube 14. For example, in one exemplary
embodiment, at least a portion of the distal end 54 or other
portion of the tube, may be compressible and the valve may be
operated to selectively compress the compressible portion and
thereby restrict cement flow through the tube. Such an embodiment
is described in more detail below.
[0065] An exemplary method of stabilizing a first vertebra and
second vertebra of a patient, including delivering of bone cement
to a bone anchor, will be described in more detail below.
Initially, a first bone anchor, such as bone anchor 16 described
above, may be implanted into a first vertebra and a second bone
anchor, such as another bone anchor 16, may be implanted in a
second vertebra. For example, the first and second bone anchors may
be implanted into the respective pedicles of adjacent vertebrae
through a posterior approach. The implantation procedure may be an
open procedure, in which, for example, the bone anchors are
implanted through a single incision, or a minimally invasive
procedure in which the first bone anchor and the second bone anchor
are implanted through separate percutaneous incisions.
[0066] The anchor connection instrument 12 may be connected to the
proximal portion 30 of the first bone anchor. For example, the
distal end 22A of the first member 20A of the anchor connection
instrument 12 may be moved, e.g., pivoted, away from the distal end
22B of the second member 20B of the anchor connection instrument 12
to separate the distal end 22A of the first member 20A from the
distal end 22B of the second member 20B. The separated distal ends
20A and 20B may then be positioned about the proximal end 30 of the
bone anchor. The distal end 22A of the first member 20A of the
anchor connection instrument 12 may be moved, e.g., pivoted, toward
the distal end 22B of the second member 20B of the anchor
connection instrument 12 until the distal ends 22A and 22B contact
the proximal end 30 of the first bone anchor to connect the anchor
connection instrument 12 to the first bone anchor.
[0067] As illustrated in FIG. 2, the cement delivery tube 14 may be
coupled to the anchor connection instrument 12 via the tube
connector 40 prior to attachment of the anchor connection
instrument 12 to the first bone anchor 12. The distal end 54 of the
cement delivery tube 14 may be positioned in the passage 34 of the
distal bone engaging portion 32 of the first bone anchor 12. In one
exemplary embodiment, the distal end 54 of the cement delivery tube
14 may be adjusted relative to one or more openings 36 in the
distal portion 34 of the first bone anchor to select the opening or
openings through which to deliver cement to the first vertebra.
[0068] The cement delivery tube 14 may be coupled to the cement
delivery system 18 before or after connection of the cement
delivery tube 14 and the anchor connection instrument 12 to the
bone anchor. In one embodiment, the bone cement may be mixed in the
reservoir 50 of the cement delivery system 18 prior to connection
to the cement delivery tube 14. In cement delivery systems 18
including a valve 60, the valve may be opened to permit cement flow
through the cement delivery tube 14. The pressure source 52 may be
operated to deliver a fluid, such as saline, under pressure to the
reservoir 50 which forces bone cement from the reservoir 50 into
the bone cement delivery tube 14, through the passage 54 in the
first bone anchor to the first vertebra.
[0069] The medical professional operating the pressure source 52
may monitor the delivery of cement to the first vertebra using an
imaging system such as a fluoroscopy system. Because the pressure
source 52 is remote from the anchor connection instrument 14 and is
outside the imaging field, the medical professional is not exposed
to radiation from the imaging system.
[0070] Once the desired amount of bone cement is delivered to the
first vertebra, the anchor connection instrument 12 and cement
delivery tube 14 may be removed from the first bone anchor and
connected to the second bone anchor, preferably while the cement
delivery tube 14 remains connected to the cement delivery system
18. Prior to disconnecting the anchor connection instrument 12 and
the cement delivery tube 14 from the first bone anchor, the valve
60, if provided, may be closed to interrupt cement delivery to the
first bone anchor and the cement delivery tube 14. In addition, the
pressure source 52 may be operated in reverse, for example to
provide for fluid flow in the direction of the pressure source, to
reduce pressure of the bone cement in cement delivery tube 14 and
to minimize leaking of cement from the distal end 54 of the cement
delivery tube 14 during removal. The fluid pressure in the cement
delivery system 18 may be monitored through a pressure indicator
62.
[0071] Once the anchor connection instrument 12 and cement delivery
tube 14 are connected to the second bone anchor, bone cement may be
delivered to the second bone anchor and the second vertebra in
accordance with the procedure described above in connection with
the first bone anchor and the first vertebra. Once the desired
amount of cement is delivered to the second vertebra, the anchor
connection instrument 12 and the cement delivery tube 14 may be
removed from the second bone anchor. A spinal connection element,
such as a spinal rod may then be connected to the first bone anchor
and the second bone anchor to stabilize the first vertebra relative
to the second vertebra. In a minimally invasive procedure, the
spinal connection element may be delivered to first bone anchor
through the percutaneous incision in which first bone anchor is
implanted and the spinal connection element may be positioned
beneath the skin and the lamina to the second bone anchor. Such a
minimally invasive procedure may be carried out using the VIPER and
VIPER II Spinal Fixation Systems available from DePuy Spine of
Raynham, Mass.
[0072] Bone cement may be injected through any number of bone
anchors, e.g., one or more bone anchors depending on, for example,
the procedure being performed and the quality of the bone of the
vertebra being stabilized. The exemplary systems and methods
described above allow multiple anchors and their respective
vertebrae to be quickly and easily filled with bone cement.
Moreover, since bone cement typically has a limited working time in
which the cement is flowable and suitable for injection, the system
and methods described above allow an increased number of anchors to
be injected with cement during the bone cement working time.
[0073] The exemplary systems and methods described above are
particularly suited for delivering bone cement. Although any type
of bone cement or bone filler may be used with these systems and
methods, a high viscosity bone cement, such as high viscosity
polymethylmethacrylate based cement available from DePuy Spine,
Inc., of Raynham Mass. (CONFIDENCE Spinal Cement), is particularly
suited for delivery using the above systems and methods.
Alternatively, the systems and methods described above may be used
to deliver other materials, such as irrigation fluid or biologics
to bone through a bone anchor.
[0074] FIGS. 7A-7D illustrate another exemplary embodiment of a
system for delivering bone cement or other materials to a bone
anchor. In the exemplary system, the cement delivery tube 14
includes a connection member 100 positioned between the proximal
end 56 of the tube 14 and the distal end 54 of the tube 14. The
connection member 100 is configured to engage the internal thread
33 provided on the proximal portion 30 of the bone anchor 16. In
the exemplary embodiment, the connection member 100 is generally
disk shaped and includes an external thread 102 complementary to
the internal thread 33 provided on the proximal portion 30 of the
bone anchor 16. The connection member 100 may be spaced a distance
D from the tip of the distal end 54 of the tube 14 selected to
allow the distal end 54 of the tube 14 to advance into the passage
34 provided in the bone anchor 16, as illustrated in FIG. 7A. In
use, the cement delivery tube 14 may be connected to the bone
anchor 16 by advancing the distal end 54 of the tube 14 into the
passage 34 of the bone anchor, as illustrated in FIG. 7B, and
rotating the tube 14 to engage the thread 102 on the connection
member 100 with the internal thread 33 of the bone anchor 16, as
illustrated in FIG. 7C. The tube 14 may be rotated until the distal
end 54 of the tube 14 reaches the desired depth within the passage
34 of the bone anchor 16, as illustrated in FIG. 7D. The tube 14
may be quickly removed from the bone anchor 16 by rotating the tube
14 in the opposite direction to disengage thread 102 from thread
33. The tube 14 may be connected to a cement delivery system such
as the cement delivery system 18 described above and cement may be
injected through one or more bone anchors in a manner analogous to
the methods described above.
[0075] FIGS. 8A-10 illustrate another exemplary embodiment of a
system for delivering bone cement or other materials to a bone
anchor. In the exemplary system, the cement delivery tube 14
includes a connection member 200 positioned between the proximal
end 56 of the tube 14 and the distal end 54 of the tube 14. Like
the connection member 100 described above, the connection member
200 is configured to engage the internal thread 33 provided on the
proximal portion 30 of the bone anchor 16. In the exemplary
embodiment, the connection member 200 is generally disk shaped and
includes an external thread 202 complementary to the internal
thread 33 provided on the proximal portion 30 of the bone anchor
16. In the exemplary embodiment, the thread 202 of the connection
member 200 is interrupted at two spaced apart, opposed unthreaded
sections 204A and 204B. The unthreaded sections 202A and 202B are
positioned diametrically opposed to one another. Thus, the
connection member 200 has a threaded section 206 interposed between
each unthreaded section 202A and 202B. The connection member 200
may be spaced a distance F from the tip of the distal end 54 of the
tube 14 selected to allow the distal end 54 of the tube 14 to be
advanced into the passage 34 provided in the bone anchor 16, as
illustrated in FIG. 8A.
[0076] In use, the cement delivery tube 14 may be connected to the
bone anchor 16 by advancing the distal end 54 of the tube 14 into
the passage 34 of the bone anchor 16, as illustrated in FIG. 8B.
During insertion of the tube 14, the connection member 200 is
oriented such that the unthreaded sections 204A and 204B face the
internally threaded portions of the proximal portion 30 of the bone
anchor 16 and the threaded sections 206 are aligned with the rod
slot 31 of the proximal portion 30 of the one anchor 16, as
illustrated in FIGS. 8C-D. Once the distal end 54 of the tube 14
reaches the desired depth within the passage 34 of the bone anchor
16, the tube 14 may be rotated approximately 90.degree. to engage
the thread 202 on the threaded portions 206 with the internal
thread 33 on the threaded portions of the bone anchor 16, as
illustrated in FIG. 8E. The tube 14 may be quickly removed from the
bone anchor 16 by rotating the tube 14 approximately 90.degree. in
the opposite direction to disengage the thread 202 on the threaded
portions 206 from thread 33. The tube 14 may be connected to a
cement delivery system such as the cement delivery system 18
described above and cement may be injected through one or more bone
anchors in a manner analogous to the methods described above.
[0077] FIGS. 11A-11B illustrate another exemplary embodiment of a
system for delivering bone cement or other materials to a bone
anchor. In the exemplary system, the cement delivery tube 14 may be
connected to bone anchor 16 with an anchor connection instrument
300 configured to engage the interior of the proximal portion 30 of
the bone anchor 16. The exemplary anchor connection instrument 300
is generally tubular in shape and has a proximal end 302, a distal
end 304, and an internal lumen or passage 306 extending from the
proximal end 302 and the distal end 304 for receiving the cement
delivery tube 14 therein. The distal end 304 of the anchor
connection instrument 300 includes two spaced-apart prongs or
fingers 308A and 308B configured to selectively engage the thread
33 on the proximal portion 30 of the bone anchor 16. The prongs
308A and 308B are diametrically opposed to each other and are
connected at a proximal end 310A, 310B to the anchor connection
instrument 300. The prongs 308A and 308B have a free distal end
312A, 312B opposite the proximal ends 310A, 310B. Each prong 308A,
308B may pivot or flex about its proximal end 310A,B between a
first, spaced-apart position, illustrated in FIG. 11A and a second,
compressed position in which the prongs 308A, 308B pivot towards
one another to facilitate insertion of the distal end 304 of the
instrument 300 into the bone anchor. The prongs 308A, 308B are
biased to the first position. The distal ends 312A, 312B of each
prong 308A, 308B includes a projection 314A, 314B for engaging the
internal thread 33 of the bone anchor 16.
[0078] In use, the anchor connection instrument 300 and the tube 14
may be advanced toward the bone anchor 16 to position the distal
end 54 of the tube 14 within the passage 34 of the bone anchor 16,
as illustrated in FIG. 11A. As the distal end 304 of the instrument
300 engages the proximal portion 30 of the bone anchor 16, the
prongs 308A and 308B are compressed to the first, compressed
position. The projections 314A and 314B may include a ramped
surface to compress the prongs 308A, 308B toward the second
position. In the second position, the projections 314A, 314B may
pass the leading edge of the thread 33 of the bone anchor 16 and
then snap into place beneath a crest of the thread 33 as the prongs
308A, 308B move to the first position thereby connecting the anchor
connection instrument 300 and the tube 14 to the bone anchor. The
anchor connection instrument 300 may be removed from the bone
anchor 16 by compressing the prongs 308A, 308B to the second
position and retracting the distal end 304 from the proximal
portion 30 of the bone anchor 16. The tube 14 may be connected to a
cement delivery system such as the cement delivery system 18
described above and cement may be injected through one or more bone
anchors in a manner analogous to the methods described above.
[0079] FIGS. 12A-12C illustrate an another exemplary embodiment of
a system for delivering bone cement or other materials to a bone
anchor. In the exemplary system, the cement delivery tube 14 may be
connected to bone anchor 16 with an anchor connection instrument
400 configured to engage the interior of the proximal portion 30 of
the bone anchor 16. The exemplary anchor connection instrument 400
is analogous in construction and use to the anchor connection
instrument 300 described above except the anchor connection
instrument 400 has a single prong 408 rather two prongs 308A, 308B.
In addition, the distal end 404 of the anchor connection instrument
400 is shaped to fit within the rod slot 31 of the bone anchor 16.
For example, the distal end 404 of the instrument 400 is generally
T-shaped having a pair of opposed extensions 420A, 420B that extend
from the instrument and that each have an arcuate lower surface for
engaging the arcuate surface on the proximal portion 30 of the bone
anchor 16 that bounds the rod slot 31. The extensions 420A, 420B,
when positioned in the rod slot 31 of the bone anchor 16, provide
stability and limit rotation of the anchor connection instrument
400 relative to the bone anchor 16. The anchor connection
instrument 300 described above in connection with FIGS. 11A and 11B
may also be provided with extensions analogous to extensions 420A,
420B.
[0080] FIGS. 13A-15 illustrate an another exemplary embodiment of a
system for delivering bone cement or other materials to a bone
anchor. In the exemplary system, a cement delivery tube 514 may be
connected to bone anchor 16 with an anchor connection instrument
500 configured to engage the interior of the proximal portion 30 of
the bone anchor 16 through a screw extension connected 516 to the
bone anchor 16. The exemplary screw extension 516 is used to
percutaneously place a bone anchor, such as bone anchor 16, and to
delivery a spinal rod to the bone anchor and other bone anchors in
a minimally invasive procedure. Exemplary screw extensions are
available in the VIPER and VIPER II Spinal Fixation Systems
available from DePuy Spine of Raynham, Mass., and are described in
U.S. Patent Application Publication Nos. US 2005/0131408 and US
2005/0131421, each of which is incorporated herein by reference.
The exemplary anchor connection instrument 500 is sized to fit
within the exemplary screw extension 516, e.g., having an external
diameter less than the inner diameter of the screw extension.
[0081] The anchor connection instrument 500 includes an inner
longitudinally adjustable member 502 that receives the cement
delivery tube 514 and an outer sleeve 504 positioned about the
inner member 502. A handle 506 is connected to the inner member
504. The inner member 502 may be adjusted between a proximal
position and a distal position relative to the outer sleeve 504.
The outer sleeve 504 has a distal end 508 having two laterally
adjustable prongs 510A, 510B. Advancement of the inner member 502
relative to the outer sleeve 504 from the proximal position to the
distal position causes the prongs 510A, 510B to move laterally, in
a direction transverse to the longitudinal axis, which facilitates
engagement with bone anchor. For example, the prongs 510A, 510B may
enter the rod slot 31 in the proximal portion 33 of the bone anchor
thereby connecting the outer sleeve 508, and the cement delivery
tube 514 to the bone anchor 30. Handle 506 may be rotated to effect
movement of the inner member between the proximal position to the
distal position.
[0082] FIGS. 16A and B illustrate another exemplary embodiment of a
cement delivery tube 614 that includes an integral valve at the
distal end of the cement delivery tube. The exemplary cement
delivery tube 614 includes a compressible section 670 in which a
portion of the wall of the tube 614 may be compressed to
selectively interrupt flow of cement through the cement delivery
tube 14. In one embodiment, for example, the cement delivery tube
14 may include an inner tube 671 constructed from a resilient
compressible material, such as a polymer, and may be selectively
encased or enclosed by a coaxial sleeve 672 of a rigid material,
such as a rigid polymer or a metal. A section of the length of the
inner tube 671 may be exposed, e.g., not enclosed, to provide the
compressible section 670 which may operate as a valve. The
compressible section 670 may be provided at any point along the
length of the tube 614.
[0083] The anchor connection instrument or other instrument may be
used to selectively compress the wall of the inner tube 671 at the
compressible section 670 to obstruct the inner tube 671. For
example, the anchor connection instrument may include a
longitudinally adjustable valve member 674 that includes a
projection 676 or the like for compressing the wall of the inner
tube 671 at the compressible section 670. The valve member 674 may
be a prong, analogous to the prongs 308A, B and 408, described
above, and may also be used to engage the instrument to the bone
anchor. In the exemplary embodiment, when the valve member 674 is
in a proximal position, the projection 676 compresses the wall of
the inner tube 671 to obstruct the inner tube 671. In a distal
position, the projection 676 abuts the rigid out sleeve 672 and the
inner tube remains unobstructed.
[0084] FIGS. 17A-17E illustrate another exemplary embodiment of a
system for delivering bone cement or other material to a bone
anchor. The exemplary system includes an anchor connection
instrument 600 including an instrument body 601 having a proximal
end 602 for connection to a cement delivery tube, such as, for
example, cement delivery tube 14 or cement delivery tube 614,
described below, a distal end 604 sized and shaped to fit within
the proximal portion 30 of the bone anchor 16, and passage 606
between the proximal end 602 and the distal end 604 through which
the cement delivery tube may be positioned to connect to the
passage 34 in the bone anchor 16.
[0085] The proximal end 602 of the exemplary instrument body 601
may include an annular collar 608 defining an opening to the
passage 606 of the instrument 600. The collar 608 may include a
connection feature to facilitate connection to the proximal end of
the cement delivery tube. The connection feature may be an external
thread, an internal thread, a groove or opening for receiving a
projection or the like, or other known connection features.
Alternatively, the collar 608 may connect to the proximal end of
the tube by a simple friction fit. In the illustrated embodiment,
the collar 608 includes a single pin 610 extending from the outer
surface of the collar 608 that engages an internal thread provided
on the proximal end 656 of the tube 614. The proximal end 602 of
the instrument body 601 further includes a flange 615 having an
outer diameter greater than the outer diameter of the collar 608.
The proximal end 656 of the tube 614 may be advanced into contact
with the flange 615, as illustrated in FIGS. 17B-D.
[0086] The distal end 604 of the anchor connection instrument 600
includes two spaced-apart arms 617A, 617B that are sized and shaped
to fit within the rod receiving slot 31 of the bone anchor 16. For
example, the distal end of the arms 617A, 617B are generally
arcuate in shape having a curvature approximating the curvature of
the rod contacting surfaces of the rod receiving slot 31.
[0087] The exemplary anchor connection instrument 600 further
includes a first member 620A that is adjustable relative to the
instrument body 601 of the instrument 600. For example, the first
member 620A may be pivotally connected to the instrument body 601
and may be pivotable between a release position, in which the
distal end 622A of the first member 620A is pivoted away from the
instrument body to facilitate removal of the instrument 600 from
the proximal end 30 of the bone anchor, and a connect position in
which the distal end 622A of the first member 620A is pivoted
toward the instrument body and the distal end 622A can engage the
proximal end 30 of the bone anchor 16 to connect the instrument 600
to the bone anchor 16. The first member 620A is connected to the
instrument body 601 by a pivot pin 619 positioned between the
proximal handle 626A of the first member 620A and the distal end
622A of the first member 622A. A spring 621 or other biasing
mechanism may be interposed between the instrument body 601 and the
first member 620A to bias the first member 620A to the connect
position. The distal end 622A of the first member 620A includes a
ramped surface 623A that is effective to pivot the distal end 622A
away from the instrument body 601, toward the release position, as
the distal end 622A is advanced distally into engagement with the
proximal end 30 of the bone anchor 16. The distal end 622A may
include a feature, such as a projection, for engaging one of the
slots 35 provided on the proximal end 30 of the bone anchor 16. In
the exemplary embodiment, the proximal terminus of the ramped
surface 623A engages one of the slots 35 provided on the proximal
end 30 of the bone anchor 16. In alternative embodiments, the
instrument 600 may include a second member, analogous in
construction to the first member 620A, pivotally connected to the
instrument body 601 at a location diametrically opposed to the
first member 620A for engaging a second one of the slots 35 on the
bone anchor 16.
[0088] The proximal end 656 of the cement delivery tube 614 is
generally annular in shape and includes an internal thread for
engaging the pin 610 provided on the collar 608 of the instrument
body. The proximal end 656 thus may be rotated into and out of
engagement with the collar 608 of the instrument body 601 to
thereby connect the tube 614 to the instrument 600 and position the
distal end 654 of the tube 614 within the channel 34 of the bone
anchor 16. The proximal end 656 of the tube 614 may also include a
luer lock connector or other connector to connect the tube 614 to
the cement delivery system 18.
[0089] In use, the cement delivery tube 614 may be connected to the
anchor connection instrument 600. The instrument 600 may be
connected to a bone anchor 16 by advancing the arms 617A, 617B into
the rod receiving slot 31 of the proximal end 30 of the bone anchor
16. During this advancement, the ramped surface 623A of the distal
end 622A of the first member 620A engages the outer surface of the
proximal end 30 of the bone anchor 16 causing the first member 620A
to pivot from the connect position toward the release position
against the spring force provided by spring 621. When the arms
617A, 617B are seated in the rod receiving slot, the proximal
terminus of the ramped surface 623A snaps into the groove 35 to
thereby connect the anchor connection instrument 600 and the cement
delivery tube 614 to the bone anchor 16. Cement from the cement
delivery system 18 may then be provided to the bone anchor 16
through the tube 614.
[0090] In procedures in which multiple bone anchors are employed, a
plurality of anchor connection instruments, including anchor
connection instrument 600, may be connected to some or all of the
bone anchors. A single cement delivery tube, such as a cement
delivery tube 614, may be used to provide a connection to the
cement delivery system 18 and deliver cement to the plurality of
bone anchors. For example, the cement delivery tube 614 may be
connected to a first anchor connection instrument 600 connected to
a first bone anchor and cement delivered to the first bone anchor.
The cement delivery tube 614 may be disconnected from the first
anchor connection instrument, while remaining connected to the
cement delivery system 18, and connected to a second anchor
connection instrument connected to a second bone anchor. Once the
desired amount of cement is delivered to the second bone anchor,
the cement delivery tube 614 may be disconnected from the second
anchor connection instrument 600 and the above process may be
repeated for other anchor connection instruments connected to the
other bone anchors. Thus, a system for delivering cement to a
plurality of bone anchors may include a plurality of anchor
connection instruments 600 and a cement delivery tube 614
connectable to each of the plurality of anchor connection
instruments 600.
[0091] Alternatively, the anchor connection instrument 600 and the
cement delivery tube 614 can be collectively connected and
disconnected as a single unit from a plurality of bone anchors in
the manner described above in connection instrument 12 and tube
14.
[0092] FIGS. 18A-18E illustrate another exemplary embodiment of a
system for delivering bone cement or other material to a bone
anchor. The exemplary system includes an anchor connection
instrument 700 that is analogous in construction to the anchor
connection instrument 600 described above except that the distal
end 704 of the instrument body 701 includes a connection member 705
that is longitudinally adjustable relative to the instrument body
701. In the exemplary instrument 700, the distal end 704 of the
instrument body 701 includes floating connection member 705 having
a generally cylindrical body 707 and an enlarged distal end 709
configured to be seated in the rod receiving slot 31 of the
proximal end 30 of the bone anchor 16. The connection member 705 is
positioned within the central passage 706 of the instrument body
701 and movable along the length of the central passage 706
relative to the instrument body 701 between an extended position in
which the distal end 709 of the connection member 705 is extended
distally away from the instrument body 701 and a retracted position
in which the distal end 709 of the connection member 705 is
positioned proximate the instrument body. FIG. 18A illustrates the
connection member 705 in the extended position. FIGS. 18B-D
illustrate the connection member 705 in the retracted position. A
spring 711 or other biasing member may be provided to bias the
connection member 705 into the extended position. The connection
member 705 and the instrument body 701 may include a retaining
feature to inhibit separation of the connection member 705 from the
instrument body 701. For example, the instrument body 701 may
include one or more projections, e.g. pins 713A, B, that project
into the central passage 706 of the instrument body 701 and engage
the connection member 705. For example, the pins 713 A, 713B may be
seated in longitudinal slots 771 provided on diametrically opposed
locations of the connection member 705.
[0093] The enlarged distal end 709 of the connection member 705 may
have an arcuate contact surface 773 sized to span the length of the
rod receiving slot 31 of the bone anchor 16. The arcuate contact
surface 773 may have a curvature that is approximately equal to the
curvature of the rod contacting surfaces of the rod receiving slot
31 of the proximal end 30 of the bone anchor 16. In addition, the
arcuate contact surface 773 may have a curvature that is
approximately equal to the curvature of the rod to be positioned
within the rod receiving slot 31 of the proximal end 30 of the bone
anchor 16.
[0094] In use, the instrument 700 may be connected to the bone
anchor 12 by positioning the connection member 705 of the
instrument 700, in the extended position, into the rod receiving
slot 31 of the proximal end 30 of the bone anchor 16, as
illustrated in FIG. 18A. Preferably, the cement delivery tube 614
is connected to the instrument 700 prior to connecting the
instrument 700 to the bone anchor 16. The distal end 654 of the
cement delivery tube 614 is positioned within the connection member
705 such that only a portion of the distal end 654 if the tube 614
extends beyond the arcuate contact surface 773. The connection
member 705 thereby serves to shield the tube 614 during the
connection process while concomitantly permitting adjustment of the
proximal end 30 of the bone anchor 16 relative to the bone engaging
portion 32 of the bone anchor 16. This adjustability facilitates
alignment of the distal end 654 of the tube 614 with the passage 34
of the bone anchor 16. As the connection instrument 700 is advanced
distally relative to the bone anchor 16 to connect to the bone
anchor 16, the connection member 705 is adjusted to the retracted
position thereby exposing more of the tube 614 for insertion into
the passage 34 of the bone anchor 16.
[0095] FIGS. 19A-19E illustrate another exemplary embodiment of a
system for delivering bone cement or other material to a bone
anchor. In the exemplary system, an anchor connection instrument
700 is configured to be positioned through a tubular screw
extension connected to the bone anchor 16. The screw extension may
be a minimally invasive screw extension such as the open screw
extension 516 described above in connection with FIGS. 13A-15, or
may be the closed minimally invasive screw extension 517
illustrated in FIGS. 19A-19E. The minimally invasive screw
extension may be connected to the bone anchor 30 and may be used to
percutaneously place a bone anchor, such as bone anchor 16, over a
guide wire in a minimally invasive procedure.
[0096] The exemplary anchor connection instrument 800 includes a
generally tubular instrument body 802 having a proximal end 806 for
connection to the proximal end of a cement delivery tube, such as
the proximal end 856 of the cement delivery tube 814, a distal end
804 configured to connect to a bone anchor, such as bone anchor 30,
and a central passage spanning from the proximal end 806 to the
distal end 804 through which the cement delivery tube may be
delivered to the bone anchor. The proximal end 806 of the
instrument 800 may include an annular collar 808 having an annular
side wall spaced apart from the outer wall of the tubular
instrument body 802. The annular collar 808 may be positioned about
the screw extension and optionally may include a connection
feature, such as a projection or a groove, to connect with a mating
connection feature on the proximal end of the screw extension 517.
The proximal end 806 may also include a connection feature to
permit the proximal end of the cement delivery tube to be connected
to the instrument 800. In the exemplary embodiment, for example,
the proximal end 806 of the instrument body 802 includes an annular
groove 809 for receiving the prongs 882A, 882B of the proximal end
856 of the cement delivery tube 814.
[0097] The distal end 804 of the instrument body 802 may include a
first connection feature for connecting to the proximal end 30 of
the bone anchor 16 and a second connection feature to connect with
the bone engaging portion 32 of the bone anchor 16. The first
connection feature 810, in the exemplary embodiment, is an
externally threaded section 810 that threadingly engages the
internal thread 33 provided on the proximal portion 30 of the bone
anchor 16 to receive a closure mechanism. The second connection
feature is a drive tip 812 that engages the drive feature provided
on the proximal head of the bone engaging portion 32 to permit the
bone engaging portion 32 to be anchored into bone. The first
connection feature and the second connection feature permit the
instrument 800 to hold the proximal rod receiving portion 30 of the
bone anchor 16 relative to the bone engaging portion 32 of the bone
anchor 16 which allows the distal tip 854 of the cement delivery
tube 814 to be more easily placed in the passage 34 of the bone
anchor 16.
[0098] The exemplary cement delivery tube 814 includes a proximal
end 856 configured to connect to the proximal end 806 of the
instrument 800 and to the cement delivery system 18 and a distal
end 865 sized to be positioned within the passage 34 of the bone
anchor 16 and deliver cement from the cement delivery system 18 to
the bone anchor 16. The proximal end 856 includes a connection
feature for connecting to a mating connection feature on the
proximal end 806 of the instrument 800. For example, the proximal
end 856 of the exemplary tube 814 includes two spaced-apart
flexible, resilient prongs 882A, 882B that may be snapped into the
groove 809 on the proximal end 806 of the instrument 800. The
proximal ends 884A, 884B of the prongs 882A, 882B may be compressed
together to release the distal ends 886A, 886B of the prongs from
the groove 809. In addition, the tube 814 may include a connection
feature, such as a leur lock connector, to connect the tube 814 to
the cement delivery system 18.
[0099] Referring to FIG. 19E, the cement delivery tube 814 may
taper from an increased inner diameter at the proximal end to 856 a
reduced diameter at the distal end 854 to maximize the flow of
cement within the tube 814 and thereby extend the working time of
the cement. In the exemplary embodiment, for example, the tube 814
includes a first section 890, a second section 892 distal to the
first section 890, and a third section 894 distal to the second
section 892. The first section 890 has a first inner diameter that
is greater than the second inner diameter of the second section
892, which is greater than the third inner diameter of the third
section 894. A first tapering section 896 interposed between the
first section 890 and the second section 892 provides a tapering
inner diameter from the first diameter to the second diameter. A
second tapering section 898 interposed between the second section
892 and the third section 894 provides a tapering inner diameter
from the second diameter to the third diameter. Any number of
different diameter sections may be provided. Alternatively, the
inner diameter of the tube may taper continuously from a diameter
at the proximal end 856 to a second diameter at the distal end
854.
[0100] The exemplary anchor connection instrument 800 and the
cement delivery tube 814 may also be used in open procedures or
procedures in which a screw extension is not connected to the bone
anchor. Referring to FIGS. 20A-E, for example, the exemplary
instrument 800 and the cement delivery tube 814 may be used in
connection with a counter-torque instrument 900 which allows the
distal end 804 of the instrument 800 to be rotated into engagement
with the proximal end 30 of the bone anchor 16. The counter-torque
instrument 900 includes a generally tubular body 902 having a
central passage through which the connection instrument 800 and the
cement delivery tube 814 may be positioned. The body 902 of the
instrument 900 may include a number of slots or openings therein to
reduce the weight of the instrument 900 and to facilitate cleaning
of the instrument. The distal end 904 of may include two spaced
apart, diametrically opposed fingers 904A, 904B for positioning
within the rod receiving slot 31 of the bone anchor 16.
[0101] In use, fingers 904A, 904B of the counter-torque instrument
900 are positioned within the rod receiving slot 31 of the bone
anchor 16 during rotational engagement and disengagement of the
externally threaded section 810 of the anchor engagement instrument
800 with the internal thread 33 provided on the proximal portion 30
of the bone anchor 16. The counter-torque instrument 900 prevents
rotation of the proximal end 30 of the bone anchor 16 relative to
the anchor connection instrument 800.
[0102] In open procedures, the length of the counter-torque
instrument 900 and the anchor connection instrument 800 may be
reduced, as illustrated in FIG. 21. FIG. 21 further illustrates
another exemplary embodiment of a bone cement delivery tube 916
having a connection feature that permits the proximal end 956 of
the tube 914 to be internally connected to the collar 808 of the
anchor connection instrument 800. The connection feature, in the
illustrated embodiment, includes one or more flexible, resilient
prongs 959 that snap fit into a groove or opening in the inner wall
of the collar 808.
[0103] The distal end of the bone cement delivery tube may be
configured to occlude a portion of the passage 34 in the bone
anchor 16 to direct bone cement through selective openings 36 in
the bone anchor 16. In one exemplary embodiment, the distal end of
a bone cement delivery tube (e.g., tube 14, tube 614, tube 814, or
tube 914) may be configured to occlude the distal end of the
passage 34 thereby directing cement through only the openings 36 in
the side wall of the bone engaging portion 32. The distal end 54 of
the cement delivery tube 14 may include occlusion 1002 that
prevents further cement flow and one or more slots or openings in
the sidewall of the tube 14 that permit cement flow from the
sidewalls rather than through a distal opening in the tube 14. In
the exemplary embodiment, two diametrically opposed slots 1004A,
1004B are provided. The size, shape, and position of the slots may
be varied depending on the desired cement flow.
[0104] In an alternative embodiment illustrated in FIG. 23, the
distal end 54 of a bone cement delivery tube 14 may include an
occlusion in the form of a plug 1006 spaced from the distal opening
1008 in the tube 14 by a wire or other reduced diameter structure.
The plug 1006 may have any shape suitable to occlude the passage 34
in the bone anchor 16. The plug 1006, in the exemplary embodiment,
is generally spherical in shape.
[0105] The distal end of a bone cement delivery tube may be
flexible to facilitate placement of the tube in the passage 34 of
the bone anchor 16. For example, the distal end 1054 of an
exemplary cement delivery tube 1104 may include lengthwise sections
of increased flexibility, as illustrated in FIG. 24A. The distal
end 1054 of the exemplary tube 1104 includes a first lengthwise
section 1056 and a second lengthwise section 1058 connected to and
distal from the first section 1056. The first section 1056 may be
constructed from a material having increased flexibility compared
to the second section 1058 and compared to the proximal section
1050. For example, the first section 1056 may be constructed of a
flexible polymer material, the second section 1058 may be
constructed from a stiffer material, such as a metal (e.g.,
stainless steel), and the proximal section 1050 may be constructed
of a stiffer material and/or have an increased wall thickness
providing increased stiffness. Any number of lengthwise sections
constructed from materials of differing flexibility may be
provided. In an alternative embodiment of a bone cement delivery
tube 1114, the continuous length of the distal end 1154 of the tube
may be constructed from a flexible material while the proximal end
1150 of the tube 1114 may be constructed of from a stiffer
material, such as a metal (e.g., stainless steel) and/or may have
an increased wall thickness to provide increased stiffness.
[0106] While the systems and methods of the present invention have
been particularly shown and described with reference to the
exemplary embodiments thereof, those of ordinary skill in the art
will understand that various changes may be made in the form and
details herein without departing from the spirit and scope of the
present invention. Those of ordinary skill in the art will
recognize or be able to ascertain many equivalents to the exemplary
embodiments described specifically herein by using no more than
routine experimentation. Such equivalents are intended to be
encompassed by the scope of the present invention and the appended
claims.
* * * * *