U.S. patent application number 11/978386 was filed with the patent office on 2008-03-06 for methods and apparatus for placing materials into bone.
This patent application is currently assigned to Kyphon, Inc. Invention is credited to Ryan Boucher, Mark A. Reiley, Michael L. Reo, Robert M. Scribner.
Application Number | 20080058826 11/978386 |
Document ID | / |
Family ID | 22462834 |
Filed Date | 2008-03-06 |
United States Patent
Application |
20080058826 |
Kind Code |
A1 |
Scribner; Robert M. ; et
al. |
March 6, 2008 |
Methods and apparatus for placing materials into bone
Abstract
A cannula establishes a subcutaneous path into bone. The cannula
includes at least one radiopaque marker. A tamping instrument
having a tamping terminus is sized and configured for manipulation
independent of the cannula to enable insertion of the tamping
instrument into the cannula, advancement of the tamping terminus in
the cannula to urge material residing in the cannula into bone, and
withdrawal of the tamping terminus from the cannula.
Inventors: |
Scribner; Robert M.; (Los
Altos, CA) ; Reo; Michael L.; (Redwood City, CA)
; Reiley; Mark A.; (Piedmont, CA) ; Boucher;
Ryan; (San Francisco, CA) |
Correspondence
Address: |
Daniel D. Ryan;RYAN KROMHOLZ & MANION, S.C.
Suite 1900
633 West Wisconsin Avenue
Milwaukee
WI
53203
US
|
Assignee: |
Kyphon, Inc
|
Family ID: |
22462834 |
Appl. No.: |
11/978386 |
Filed: |
October 29, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11599943 |
Nov 15, 2006 |
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|
11978386 |
Oct 29, 2007 |
|
|
|
10617976 |
Jul 11, 2003 |
7153307 |
|
|
11599943 |
Nov 15, 2006 |
|
|
|
09804107 |
Mar 12, 2001 |
6613054 |
|
|
10617976 |
Jul 11, 2003 |
|
|
|
09134323 |
Aug 14, 1998 |
6241734 |
|
|
09804107 |
Mar 12, 2001 |
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Current U.S.
Class: |
606/93 |
Current CPC
Class: |
A61B 2017/00464
20130101; A61F 2/4601 20130101; A61B 2017/00261 20130101; A61B
17/3472 20130101; A61B 17/7097 20130101; A61B 17/8855 20130101;
A61B 17/8822 20130101; A61F 2/44 20130101; A61F 2002/4662 20130101;
A61F 2250/0098 20130101; A61F 2310/00353 20130101; A61B 2050/0065
20160201; A61B 90/39 20160201; A61F 2002/2835 20130101; A61B
17/1671 20130101; A61B 17/8805 20130101; A61B 17/8816 20130101;
A61B 2090/062 20160201; A61F 2002/3008 20130101; A61B 50/33
20160201; A61B 2017/00867 20130101; A61B 17/8833 20130101; A61F
2/4603 20130101 |
Class at
Publication: |
606/093 |
International
Class: |
A61B 17/58 20060101
A61B017/58 |
Claims
1. Apparatus for delivering material into bone comprising a cannula
for establishing a subcutaneous path into bone and including at
least one radiopaque marker, and a tamping instrument having a
tamping terminus, the tamping instrument being sized and configured
for manipulation independent of the cannula to enable insertion of
the tamping instrument into the cannula, advancement of the tamping
terminus in the cannula to urge material residing in the cannula
into bone, and withdrawal of the tamping terminus from the
cannula.
2. Apparatus according to claim 1 wherein the cannula has a length,
and wherein the length of the tamping instrument exceeds the length
of the cannula.
3. Apparatus according to claim 1 wherein a removable handle is
carried by the proximal end of the cannula.
4. Apparatus according to claim 1 wherein a handle is carried by
the proximal end of the tamping instrument.
5. Apparatus according to claim 4 wherein, when the tamping
instrument is fully inserted into the cannula, the handle is
adjacent the proximal end of the cannula.
6. Apparatus according to claim 1 wherein the cannula comprises a
generally rigid material.
7. Apparatus according to claim 1 wherein the tamping instrument
comprises a generally rigid material.
8. Apparatus according to claim 1 wherein the tamping instrument
has a blunt distal end.
9. Apparatus according to claim 1 wherein the cannula has a blunt
distal end.
10. Apparatus according to claim 1 wherein the tamping instrument
and the cannula each have a blunt distal end.
11. Apparatus according to claim 1 further comprising a delivery
device to convey material into the cannula.
12. Apparatus according to claim 1 wherein the tamping instrument
includes at least one marking to visually gauge the advancement the
terminus relative to the distal end of the cannula.
13. Apparatus according to claim 1 wherein the tamping instrument
includes a set point marking spaced from the terminus at a distance
generally equal to the length of the cannula.
14. Apparatus according to claim 12 wherein the tamping instrument
includes at least one additional marking to visually gauge
advancement of the terminus relative to the distal end of the
cannula.
15. Apparatus according to claim 1 wherein the tamping instrument
includes at least one radiopaque marker.
16. Apparatus according to claim 1 wherein the cannula is
plastic.
17. Apparatus according to claim 16 wherein the tamping instrument
is plastic.
18. Apparatus according to claim 1 wherein the tamping instrument
has a substantially constant diameter along its length.
19. Apparatus according to claim 1 wherein the material comprises
at least one of bone cement, autograft material, allograft
material, calcium carbonate, demineralized bone matrix material,
calcium phosphate.
20. Apparatus for delivering material into bone comprising a
cannula for establishing a subcutaneous path into bone, the cannula
including at least one radiopaque marker and being sized and
configured to accept insertion and withdrawal of a first instrument
in the cannula, and a tamping instrument separate from the first
instrument having a tamping terminus, the tamping instrument being
sized and configured for manipulation independent of the cannula to
enable insertion of the tamping instrument into the cannula and
advancement of the tamping terminus in the cannula to urge material
residing in the cannula into the bone.
21. Apparatus for delivering material into bone comprising a
cannula for establishing a subcutaneous path into bone, the cannula
being sized and configured to accept insertion and withdrawal of a
first instrument in the cannula, and a tamping instrument separate
from the first instrument having a tamping terminus, the tamping
instrument including at least one marking to visually gauge the
advancement of the terminus relative to the distal end of the
cannula and being sized and configured for manipulation independent
of the cannula to enable insertion of the tamping instrument into
the cannula and advancement of the tamping terminus in the cannula
to urge material residing the cannula into bone.
22. Apparatus according to claim 21 wherein the tamping instrument
includes a set point marking spaced from the terminus at a distance
generally equal to the length of the cannula.
23. Apparatus according to claim 22 wherein the tamping instrument
includes at least one additional marking to visually gauge
advancement of the terminus relative to the distal end of the
cannula.
24. A method comprising providing apparatus as defined in claim 1,
and manipulating the apparatus for delivering material into bone
relying at least in part upon viewing the at least one radiopaque
marker.
25. A method comprising deploying an expandable device through a
percutaneous path into a vertebral body having a cancellous bone
volume to create a cavity in the cancellous bone volume, advancing
a tamping instrument through a percutaneous cannula to deliver
material into the cavity, and gauging the advancement by observing
at least one predetermined radiopaque marker to determine a
position of a terminus of the tamping instrument relative to a
distal end of the cannula.
Description
RELATED APPLICATIONS
[0001] This application is a divisional of co-pending U.S. patent
application Ser. No. 11/599,943, filed Nov. 15, 2006, and entitled
"Systems and Methods for Placing Materials into Bone," which is a
divisional of U.S. patent application Ser. No. 10/617,976, filed
Jul. 11, 2003 (now U.S. Pat. No. 7,153,307), which is a divisional
of U.S. patent application Ser. No. 09/804,107, filed Mar. 12, 2001
(now U.S. Pat. No. 6,613,054), which is a divisional of U.S. patent
application Ser. No. 09/134,323, filed Aug. 14, 1998 (now U.S. Pat.
No. 6,241,734).
FIELD OF THE INVENTION
[0002] The invention generally relates to the treatment of bone
conditions in humans and other animals.
BACKGROUND OF THE INVENTION
[0003] Injection devices similar to a household caulking gun are
used to inject bone cement into bone. A typical bone cement
injection device has a pistol shaped body, which supports a
cartridge containing bone cement. A trigger actuates a
spring-loaded ram, which forces a volume of bone cement in a
viscous condition through a suitable nozzle and into the interior
of a bone targeted for treatment. According to the teachings of
U.S. Pat. Nos. 4,969,888 and 5,108,404, a cavity can be first
formed by compacting cancellous bone inside the bone, into which
the bone cement is injected. Conventional cement injection devices
provide no opportunity to override the spring action and quickly
terminate the flow of cement, should the cavity fill before the
spring-actuated load cycle is completed. Furthermore, once the
spring-actuated mechanism is triggered, conventional cement
injection devices do not permit the injection volume or inject rate
to be adjusted or controlled in real time, in reaction to
cancellous bone volume and density conditions encountered inside
bone.
[0004] In a clinical procedure called vertebroplasty, bone cement
is injected at high pressure (typically, about 700 psi) into the
interior of a vertebral body, without the prior formation of a
cavity. Because high pressure is used, there is little opportunity
to quickly and accurately adjust cement flow in reaction to bone
volume and density conditions encountered. Momentum generated by
high pressure-induced cement flow continues to propel cement into
the targeted bone site even after termination of the high
pressure.
[0005] As a result of the relatively high pressure that
conventional procedures rely upon, coupled with the effective lack
of a short response time, the targeted bone interior can suddenly
overfill. Excess filling material can be forced outside the bone
interior, and into adjoining tissue regions, where the presence of
filling material is not required or desired.
[0006] For these and other reasons, there is a need for new systems
and methods for placing material into bones, with greater rate and
volume control, a faster response time, and without requiring the
use of high pressure.
SUMMARY OF THE INVENTION
[0007] The invention provides instruments, systems, and methods,
which, in use, enable greater control over the placement of
materials into bone.
[0008] One aspect of the invention provides apparatus including a
cannula that establishes a subcutaneous path into bone. The cannula
includes at least one radiopaque marker. The apparatus includes a
tamping instrument having a tamping terminus. The tamping
instrument is sized and configured for manipulation independent of
the cannula to enable insertion of the tamping instrument into the
cannula, advancement of the tamping terminus in the cannula to urge
material residing in the cannula into bone, and withdrawal of the
tamping terminus from the cannula.
[0009] Another aspect of the invention provides a method. The
method comprises providing apparatus including a cannula that
establishes a subcutaneous path into bone. The cannula includes at
least one radiopaque marker. The apparatus includes a tamping
instrument having a tamping terminus. The tamping instrument is
sized and configured for manipulation independent of the cannula to
enable insertion of the tamping instrument into the cannula,
advancement of the tamping terminus in the cannula to urge material
residing in the cannula into bone, and withdrawal of the tamping
terminus from the cannula. The method includes manipulating the
apparatus for delivering material into bone relying at least in
part upon viewing the at least one radiopaque marker.
[0010] Features and advantages of the inventions are set forth in
the following Description and Drawings, as well as in the appended
Claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a plane view of a kit housing a system of
functional instruments, which, in use, gain subcutaneous access to
the inside of a bone to compact cancellous bone and form a cavity
for therapeutic purposes;
[0012] FIG. 2 is an exploded perspective view of the kit shown in
FIG. 1;
[0013] FIG. 3 is a perspective view of the subcutaneous access
instrument group that forms a part of the system shown in FIG.
1;
[0014] FIG. 4A is a perspective view of the cavity forming
instrument that forms a part of the system shown in FIG. 1;
[0015] FIG. 4B is a section view of the catheter tube of the cavity
forming instrument, taken generally along line 4B-4B in FIG. 1;
[0016] FIG. 4C is an end view of an alternative embodiment of the
cavity forming instrument shown in FIG. 4A, having a prebent
stylet;
[0017] FIG. 5 is a perspective view of the material introducing
instrument group that forms a part of the system shown in FIG.
1;
[0018] FIGS. 6 and 7 are, respectively, top and side views of a
human vertebral body;
[0019] FIG. 8 is a top view of a vertebral body during insertion of
a spinal needle instrument to begin a bone access procedure;
[0020] FIGS. 9 to 11 are top views showing subsequent steps, after
insertion of the spinal needle instrument shown in FIG. 8, of
inserting a guide pin instrument into the vertebral body;
[0021] FIG. 12 is a perspective view showing a subsequent step,
after insertion of the guide pin instrument shown in FIGS. 9 to 11,
which deploys an obturator instrument deployed over the guide pin
instrument with aid of a handle;
[0022] FIG. 13 is a top view of the vertebral body, with the
obturator instrument shown in FIG. 12 deployed;
[0023] FIG. 14 is a perspective view showing a subsequent step,
after insertion of the obturator instrument shown in FIG. 12, which
uses the handle shown in FIG. 12 to aid in the deployment of a
cannula instrument over the obturator instrument;
[0024] FIG. 15 is a top view of the vertebral body, with the
cannula instrument shown in FIG. 14 deployed;
[0025] FIG. 16 is a perspective view showing a subsequent step,
after insertion of the cannula instrument shown in FIG. 14, which
removes the obturator instrument from the cannula instrument, to
leave the cannula instrument and guide pin instrument in place;
[0026] FIG. 17 is a top view of the vertebral body, after the
obturator removal step shown in FIG. 16, leaving the cannula
instrument and guide pin instrument in place;
[0027] FIG. 18 is a perspective view showing a subsequent step,
after removal of the obturator instrument shown in FIG. 16, which
uses the handle shown in FIG. 14 to aid in the deployment of a
drill bit instrument through the cannula instrument along the guide
pin instrument;
[0028] FIG. 19 is a top view of the vertebral body, as the drill
bit instrument shown in FIG. 18 is deployed with aid of the handle
to open a passage into the interior volume of the vertebral
body;
[0029] FIG. 20 is a perspective view showing a subsequent step,
after removal of the drill bit instrument and guide pin instrument
shown in FIG. 18, of deploying the cavity forming instrument into
the vertebral body;
[0030] FIG. 21 is a top view of the vertebral body, as the
expandable structure carried by the cavity forming instrument shown
in FIG. 20 is deployed into the interior volume of the vertebral
body;
[0031] FIG. 22 is a top view of the vertebral body, as the
expandable structure shown in a collapsed condition in FIG. 21 is
expanded to compact cancellous bone and form a cavity;
[0032] FIG. 23 is a top view of the vertebral body, after removal
of the expandable structure, showing the cavity formed by
compacting cancellous bone;
[0033] FIG. 24 is a perspective view of the syringe of the material
introducing instrument group, shown in FIG. 5, being filled with a
material selected for introduction into the cavity shown in FIG.
23;
[0034] FIG. 25 is a perspective view of the syringe shown in FIG.
24 being joined to a nozzle, which also forms a part of the
material introducing instrument group shown in FIG. 5;
[0035] FIG. 26 is a perspective view showing the syringe and
attached nozzle shown in FIG. 25 being deployed through the cannula
instrument in preparation of introducing material into the
cavity;
[0036] FIGS. 27 and 28 are perspective and top views, respectively,
showing the syringe and attached nozzle shown in FIG. 26 in use to
inject material into the cannula instrument for passage into the
cavity;
[0037] FIG. 29 is a top view of the vertebral body after a measured
volume of material has been injected and the syringe and attached
nozzle withdrawn from the cannula instrument;
[0038] FIG. 30 is a top view showing the deployment of a tamping
instrument, which forms a part of the material introducing
instrument group shown in FIG. 5, being deployed in the cannula
instrument;
[0039] FIG. 31 is a top view showing advancement of the tamping
instrument in the cannula instrument to displace and distribute
material from the cannula instrument into the cavity;
[0040] FIG. 32 is a top view of the vertebral body after removal of
the tamping instrument and cannula instrument, showing the cavity,
now filled with the material;
[0041] FIG. 33 is a perspective view of a reduced diameter cannula
instrument and associated reduced diameter material introducing
instruments, which embody features of the invention;
[0042] FIG. 34 is a perspective view of a cavity forming instrument
having an expandable cavity forming structure, which, in use, is
deployed using the reduced diameter cannula instrument shown in
FIG. 33, the cavity forming instrument having a sliding introducer
sleeve shown in its rearward position;
[0043] FIG. 35 is a perspective view of the cavity forming
instrument shown in FIG. 34, with the introducer sleeve moved
forward to overlie and compress the expandable cavity forming
structure;
[0044] FIG. 36 is a perspective view of the cavity forming
structure shown in FIG. 35, with the introducer sleeve (shown
partially in section) coupled to the proximal end of the cannula
instrument, to guide the expandable structure compressed within the
sleeve into the reduced diameter cannula instrument without damage;
and;
[0045] FIG. 37 is a perspective view of the cavity forming
structure shown in FIG. 36, after the expandable structure has been
guided by the introducer sleeve into the cannula instrument and is
being advanced through the cannula instrument for deployment in
bone.
[0046] The invention may be embodied in several forms without
departing from its spirit or essential characteristics. The scope
of the invention is defined in the appended claims, rather than in
the specific description preceding them. All embodiments that fall
within the meaning and range of equivalency of the claims are
therefore intended to be embraced by the claims.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0047] FIGS. 1 and 2 show a system 10 of functional instruments. In
use, certain instruments of the system 10 are deployed in a
purposeful manner to penetrate tissue and gain subcutaneous access
to the inside of a bone. Inside bone, other instruments of the
system 10 are deployed to form a cavity in cancellous bone, into
which a material is placed for therapeutic purposes.
[0048] In the illustrated embodiment, the system 10 is arranged as
a prepackage kit 12 in three functional instrument groups 14, 16,
and 18. The first group 14 (which FIG. 3 shows outside the kit 12)
comprises instruments whose purpose is to gain subcutaneous access
to a bone interior. The second group 16 (which FIG. 4 shows outside
the kit 12) comprises an instrument whose function is to create a
cavity in cancellous bone. The third group 18 (which FIG. 5 shows
outside the kit 12) comprises instruments whose function is to
introduce a material into the cavity.
[0049] The kit 12 can take various forms. In the illustrated
embodiment, the kit 12 comprises a sterile, wrapped assembly.
[0050] Further details of each functional instrument group 14, 16,
and 18 and the kit 12 follow.
I. The Subcutaneous Access Instrument Group
[0051] The number and type of instruments in the group 14 can vary.
FIG. 3 shows five representative instruments, each having a
different size and function.
[0052] A. The Spinal Needle and Guide Pin
[0053] As FIG. 3 shows, one instrument comprises a conventional
spinal needle assembly 20 and a guide pin instrument 26.
[0054] In use, the spinal needle assembly 20 establishes the
initial subcutaneous path leading to the targeted treatment site.
The guide pin instrument 26 is deployed through this path, followed
by progressively larger instruments, as will be described
later.
[0055] The spinal needle assembly 20 comprises a stylet 22, which
is slidably deployed within a stylus 24. The stylus 24 typically
has, for example, about an eleven gauge diameter. Other gauge
diameters can be used, according to the gauge of the guide pin
instrument 26 used.
[0056] In use, the guide pin instrument 26 is deployed through the
subcutaneous path established by the spinal needle assembly 20, by
exchange with the needle stylet 22. The guide pin instrument 26
serves to guide the establishment of the main operative pathway to
the targeted treatment site.
[0057] The remaining instruments 28, 30, and 32 in the group 14
share some common features, although they are intended, in use, to
perform different functions.
[0058] These instruments 28, 30, and 32 are each made of a rigid,
surgical grade plastic or metal material. These instruments 28, 30,
and 32 each comprises an elongated, cylindrical body having a
proximal end 34 and a distal end 36.
[0059] B. The Obturator Instrument
[0060] The instrument 28 functions as an obturator. Its distal end
36 is tapered to present a penetrating surface 38. In use, the
surface 38 is intended to penetrate soft tissue in response to
pushing or twisting forces applied by the physician at the proximal
end 34.
[0061] The proximal end 34 of the obturator instrument 28 presents
a flanged surface 40, which tapers from a larger outer diameter to
a smaller outer diameter in the direction of the proximal end 34.
The flanged surface 40 includes an array of circumferentially
spaced teeth 42.
[0062] An interior lumen 44 extends through the obturator
instrument 28 from the distal end 36 to the proximal end 34. The
interior lumen 44 is sized to accommodate the guide pin instrument
26, as will be described in greater detail later.
[0063] C. The Cannula Instrument
[0064] The instrument 30 functions as a cannula or guide sheath.
The cannula instrument 30 is somewhat larger in diameter than and
not as long as the obturator instrument 28. The cannula instrument
30 includes an interior lumen 46 that extends from its distal end
36 to its proximal end 34. The interior lumen 46 is sized to accept
the obturator instrument 28. The size of the interior lumen 46
permits a physician to slide and rotate the cannula instrument 30
relative to the obturator instrument 28, and vice versa, as will be
described in greater detail later.
[0065] The distal end 36 of the cannula instrument 30 presents an
end surface 48. In use, the end surface 48 of the cannula
instrument 30 is intended to penetrate soft tissue surrounding the
obturator instrument 28 in response to pushing or twisting forces
applied at the proximal end 34.
[0066] The proximal end 34 carries an enlarged fitting 50. The
fitting 50 tapers from a larger diameter to a smaller diameter in
the direction of the proximal end 34. Like the tapered flange 40 on
the obturator instrument 28, the tapered fitting 50 has an array of
circumferentially spaced teeth 52. The tapered fitting 50 of the
cannula instrument 30 possesses a larger maximum outer diameter
than the maximum outer diameter of the tapered flange 40 of the
obturator instrument 28.
[0067] The cannula instrument 30 includes measured markings 118
along its length (see FIG. 3). The measured markings 118 gauge the
depth of insertion. The markings 118 can be placed, for example, at
one centimeter intervals. As FIG. 3 shows, the markings 118 can be
consecutively numbered, beginning at the distal end 36, so that the
physician can ascertain the insertion depth at a glance.
[0068] D. The Drill Bit Instrument
[0069] The instrument 32 functions as a drill bit. The drill bit
instrument 32 has generally the same physical dimensions as the
obturator instrument 28. Like the obturator instrument 28, the
drill bit instrument 32 is intended, in use, to fit for sliding and
rotational movement within the interior lumen 46 of the cannula
instrument 30.
[0070] The distal end 36 of the drill bit instrument 32 includes
machined cutting edges 54. In use, the cutting edges 54 are
intended to penetrate hard tissue in response to rotation and
longitudinal load forces applied at the proximal end 34 of the
drill bit instrument 32.
[0071] The proximal end 34 presents a tapered flange 56, which is
substantially identical to the flange 40 on the obturator
instrument 28. Like the obturator instrument 28, the tapered flange
56 changes from a larger diameter to a smaller diameter in the
direction of the proximal end 34. The tapered flange 56 of the
drill bit instrument 32 also includes an array of circumferentially
spaced teeth 58. The form and orientation of the teeth 58 on the
drill bit instrument 32 correspond to the form and orientation of
the teeth 42 on the obturator instrument 28.
[0072] E. The Handle
[0073] The group includes a handle 60. The handle 60 engages the
functional instruments 28, 30, and 32 in a removable, slip fit
fashion to aid a physician in manipulating the instruments during
use.
[0074] The handle 60 is made from a molded or cast rigid plastic or
metal material. The handle 60 is shaped to be comfortably and
securely grasped by a normal human hand. The shape and size to
accommodate this function can, of course, vary. In the illustrated
embodiment, the handle 60 is elongated along a main axis to fit
comfortably across the palm of the hand.
[0075] The handle 60 includes a center post 62, which is integrally
molded to the handle 60 about its geometric center. The center post
62 extends downward to give the handle 60 a general T-shape.
[0076] The handle 60 includes two interior cavities or sockets 64
and 66 in the center post 62. The sockets guide the attachment
between the handle 60 and the instruments 28, 30, and 32. The first
and second sockets 64 and 66 are sized to present unique attachment
sites for different functional instruments.
[0077] The first socket 64 includes an array of circumferentially
spaced grooves 68, which, in form and orientation, match the teeth
42 and 58 at the proximal ends 34 of the obturator instrument 28
and the drill bit instrument 32. The first socket 64 accepts the
tapered flange 40 or 56 of either the obturator instrument 28 or
the drill bit instrument 32. The teeth 42 and 58 of either tapered
flange 40 or 56 mesh in a slip-fit with the grooves 68 of the first
socket 64. The running slip-fit allows longitudinal force to be
applied to either instrument 28 or 32 through the handle 60. The
running slip-fit also prevents relative rotation between either
instrument 28 or 32 and the first socket 64, thereby permitting
torsional or twisting forces to be applied to either instrument 28
or 32 by the handle 60, with an increased mechanical advantage.
[0078] The second socket 66 is larger than the first socket 64 and
is sized to accept the larger tapered fitting 50 of the cannula
instrument 30. The second socket 66 includes an array of
circumferentially spaced grooves 70, which, in form and
orientation, match the teeth 52 on the tapered fitting 50. The
teeth 52 of the tapered fitting 50 mesh in a slip-fit with the
grooves 70 of the second socket 66. The running slip-fit allows
both longitudinal and torsional forces to be applied to the cannula
instrument 30 through the handle 60, with increased mechanical
advantage.
[0079] As shown in phantom lines in FIG. 3, a first passage 72
extends through the top of the handle 60, through the center post
62, and into the first socket 64. The passage 72 is generally
aligned with the center of the first socket 64 and is sized to pass
the guide pin instrument 26 (see FIG. 12).
[0080] Likewise, as also shown in phantom lines in FIG. 3) a second
passage 74 extends through the top of the handle 60, through the
center post 62, and into the second socket 66. The passage 74 is
generally aligned with the center of the second socket 66 and is
sized to pass the either obturator instrument 28 or the drill bit
instrument 32 (see FIG. 14).
[0081] Further details of the handle 60 can be found in co-pending
U.S. patent application Ser. No. 09/014,229, filed Jan. 27, 1998,
and entitled AA Slip-Fit Handle for Hand-Held Instruments that
Access Interior Body Regions.
[0082] Further details regarding the use of the handle 60 and the
associated instruments 26, 28, and 30 will be provided later.
II. The Cavity Forming Instrument
[0083] As FIG. 4A shows, the group 16 includes an instrument 76,
which is deployed through the cannula instrument 30 to a location
inside bone (see FIG. 20). When so deployed, the instrument 76
serves to form a cavity in cancellous bone.
[0084] The instrument 76 can be constructed in various ways. In the
illustrated embodiment, the instrument 76 includes a flexible
catheter tube 78 having a proximal end 80 and a distal end 82. The
proximal end 80 carries a handle grip 84 to facilitate gripping and
maneuvering the catheter tube 78. The materials for the catheter
tube 78 are selected to facilitate its advancement through the
cannula instrument 30. The catheter tube 78 can be constructed, for
example, using standard flexible, medical grade plastic materials,
like vinyl, nylon, polyethylenes, ionomer, polyurethane, and
polyethylene tetraphthalate (PET). The catheter tube 78 can also
include more rigid materials to impart greater stiffness and
thereby aid in its manipulation. More rigid materials that can be
used for this purpose include stainless steel, nickel-titanium
alloys (NitinolJ material), and other metal alloys.
[0085] The distal end 82 of the instrument 76 carries an expandable
structure 86. In the illustrated embodiment, the expandable
structure 86 is made from a polyurethane or an elastomer (e.g.,
silicone or nylon) material. The structure 86 has been preformed to
possess a desired shape by exposure to heat and pressure, e.g.,
through the use of conventional thermoforming techniques.
[0086] As FIG. 4B shows, the catheter body 78 includes an interior
lumen 88, which communicates with the interior of the structure 86.
A fitting 90 on the proximal end 80 of the catheter tube 78 (see
FIG. 4B) communicates with the lumen 88. The fitting 90 couples the
lumen 88 to a source 92 of fluid, e.g., sterile saline (see FIG.
21), or a radiopaque contrast medium.
[0087] The fluid is introduced from the source 92 into the
structure 86 under positive pressure, causing the structure 86 to
expand. During expansion inside bone, the material selected for the
structure 86 preferably resists deformation, so that the expanded
shape inside bone essentially corresponds to its expanded shape
outside bone, i.e., when in an open air environment. This allows
the physician to select in an open air environment a structure 86
having an expanded shape desired to meet the targeted therapeutic
result, with the confidence that the expanded shape inside bone
will be similar in important respects. In addition to being able to
expand its volume while resisting deformation inside bone, the
material of the structure 86 preferable withstands abrasion,
tearing, and puncture when in contact with cancellous bone.
[0088] The shape of the structure 86, when expanded inside bone, is
selected by the physician, taking into account the morphology and
geometry of the site to be treated. The shape of the cancellous
bone to be compressed, and the local structures that could be
harmed if bone were moved inappropriately, are generally understood
by medical professionals using textbooks of human skeletal anatomy
along with their knowledge of the site and its disease or injury.
The physician is also able to select the expanded shape inside bone
based upon prior analysis of the morphology of the targeted bone
using, for example, plain film x-ray, fluroscopic x-ray, or MRI or
CT scanning. The expanded shape inside bone is selected to optimize
the formation of a cavity that, e.g., when filled with a suitable
material, provides support across the region of the bone being
treated.
[0089] As one general guideline, in cases where the bone disease
causing fracture (or the risk of fracture) is the loss of
cancellous bone mass (as in osteoporosis), the selection of the
expanded shape of the structure 86 inside bone should take into
account that from 30% to 90% of the cancellous bone volume should
be compacted. Another general guideline is the amount that the
targeted fractured bone region has been displaced or depressed. The
expansion of the structure 86 within the cancellous bone region
inside a bone can elevate or push the fractured cortical wall back
to or near its anatomic position occupied before fracture
occurred.
[0090] In the illustrated embodiment (see FIG. 4A), the structure
86 possesses a preformed hour-glass or peanut shape. This shape is
selected in contemplation of deploying the structure 86 in a
vertebral body, as will be described in greater detail later.
[0091] To facilitate deployment of the structure 86 through the
cannula instrument 30, the catheter tube 78 includes a second
interior lumen 94. The lumen 94 extends from a second fitting 98 on
the proximal end 80 of the catheter tube 78, through the body of
the cannula tube 78, and through the interior of the structure 86
to the tip end 172 of the structure 86. The lumen 94 receives a
generally stiff stylet 96, which can be made from a molded plastic
or stainless steel material. The stylet 96 is inserted through the
fitting 98 into the lumen 94, and includes a threaded coupling 100
to secure the stylet 96 against movement. The presence of the
stylet 96 serves to keep the structure 86 in the desired distally
straightened condition during passage through the cannula
instrument 30 into the targeted tissue region. Once the structure
86 is free of the cannula instrument 30 and inside bone, the stylet
96 can be withdrawn (shown by arrow 174 in FIG. 4A). This returns
normal flexibility to the catheter tube 78 and facilitates
manipulation of the structure 86 inside bone. With the stylet 96
withdrawn, the lumen 94 can also serve as a pathway for introducing
rinsing liquid or to aspirate debris from the bone.
[0092] In the illustrated embodiment, the stylet 96 is biased
toward a generally straight condition. In an alternative embodiment
(see FIG. 4C), a stylet 102 can have a preformed memory, to
normally bend its distal region. The memory is overcome to
straighten the stylet 102 when confined within the cannula
instrument 30. However, as the structure 86 and distal region of
the preformed stylet 102 advance free of the cannula instrument 30,
to pass into the targeted region, the preformed memory bends the
distal region of the stylet 102 and thereby shifts the main axis of
the expandable structure 86. The prebent stylet 102, positioned
within the interior of the structure 86, aids in altering the
orientation of the structure 86, bringing it into better anatomic
alignment with the targeted region.
[0093] Other types of instruments that can form cavities in
cancellous bone and other interior body regions are described in
copending U.S. patent application Ser. No. 09/055,805, entitled
AStructures and Methods for Creating Cavities in Interior Body
Regions,@ filed Apr. 6, 1998.
III. The Material Introducing Instrument Group
[0094] The group 18 includes instruments 104, 106, and 108 which
serve to convey and compact a selected material inside the cavity
formed by the structure 86. The material in the cavity provides a
desired therapeutic result, e.g., replacement of tissue mass, or
renewed interior support for the bone, or the delivery of
medication, or combinations thereof. Accordingly, the material to
perform this function can be selected from among, e.g., a material
that sets to a hardened condition, including bone cement, autograft
tissue, allograft tissue, synthetic bone substitute, as well as a
medication, or combinations thereof.
[0095] In the illustrated embodiment, the group 18 comprises
material injection instruments 104 and 106 and a material tamping
instrument 108, which deliver material at a low delivery pressure,
i.e., a pressure no greater than about 360 psi.
[0096] A. Low Pressure Material Injection Instruments
[0097] In the illustrated embodiment, the material is injected by
use of a conventional syringe 104, to which a specially designed
injection nozzle 106 is coupled. A manual actuated syringe with a
push plunger can be used. Alternatively, a LeVeen Inflation Syringe
with threaded plunger can be used, which can be actuated manually
or by use of a mechanical actuator.
[0098] In the illustrated embodiment, the syringe 104 is made from
a clear plastic material. The syringe 104 includes a chamber 110,
which receives the material to be injected. The material is
expressed from the chamber 100 by a manually advanced syringe
piston 112 (see also FIG. 25).
[0099] The injection nozzle 106 connects by a threaded connector
114 to the end of the syringe 104 9 (see also FIG. 25). In the
illustrated embodiment, the nozzle 106 is made from a generally
flexible, inert plastic material, such as such as polyethylene or
another suitable polymer. Alternatively, the nozzle 106 can be made
from a generally rigid plastic or metal material.
[0100] The injection nozzle 106 is sized to be advanced through the
cannula instrument 30 (see FIG. 26). The nozzle 106 includes
measured markings 116 along its length. The markings 116 can be
placed, for example, at one centimeter intervals, to correspond
with the markings 118 on the cannula instrument 30, so that the
relative position of the nozzle 106 within the cannula instrument
30 can be gauged. The markings 118 can, e.g., include a set point
176. Alignment of the set point 176 at the proximal end 34 of the
cannula instrument 30, indicates that the distal end of the nozzle
106 is located in an aligned relationship with the distal end 36 of
the cannula instrument 30. In this arrangement, the markings 118
are consecutively numbered with positive numbers proximally of the
set point 176 and with negative numbers distally of the set point
176. The physician is thereby able to tell at a glance the location
of the distal end of the nozzle 106, in terms of how far beyond or
short of the distal end 36 of the cannula instrument 30 it is.
[0101] In use, the distal end of the nozzle 106 is located beyond
the distal end 36 of the cannula instrument 30 within the cavity
formed in the targeted tissue region. As FIG. 5 shows, the distal
end of the nozzle 106, when made from a plastic material, can carry
at least one radiopaque marker 208, to enable remote visualization
of the nozzle position within the body. The syringe 104 ejects a
predetermined volume of material into the nozzle 106 in a low
pressure stream into the cavity. As the material fills the cavity,
the nozzle (still ejecting material) is retracted from the cavity
and into the cannula instrument 30 itself. Further details of this
function and result will be provided later.
[0102] B. The Material Tamping Instrument
[0103] The group 18 also includes a material tamping instrument
108. The tamping instrument 108 is made from generally rigid, inert
plastic or metal material. The tamping instrument 108 is also sized
to be advanced into the cannula instrument 30 (see FIG. 30). The
free end 124 of the tamping instrument 108 is ribbed or contoured
to facilitate gripping the instrument 108 during use.
[0104] The tamping instrument 108 includes measured markings 122
along its length. The markings 116 can be placed, for example, at
one centimeter intervals, to correspond with the markings 118 on
the cannula instrument 30, so that the relative position of the
tamping instrument 108 within the cannula instrument 30 can be
gauged. Like the nozzle 106, the markings 122 on the tamping
instrument 108 includes a set point 178, which indicates when the
distal end of the tamping instrument 108 aligns with the distal end
36 of the cannula instrument 30. Also like the nozzle 106, the
markings 122 on the tamping instrument 108 are consecutively
numbered with positive numbers proximally of the set point 178 and
with negative numbers distally of the set point 178. The physician
is thereby able to tell at a glance the location of the end of the
tamping instrument 108, in terms of how far beyond or short of the
distal end 36 of the cannula instrument 30 it is. As FIG. 5 also
shows, the end of the tamping instrument 108, when made from a
plastic material, can carry at least one radiopaque marker 210, so
that its position can be visualized from outside the body.
[0105] After withdrawal of the nozzle 106 from the cannula
instrument 30, residual material is left in the cannula instrument
30. The purpose of the tamping instrument 108 is to displace the
residual material out the distal end 36 of the cannula instrument
30 and into the cavity, to thereby fill the cavity without exerting
undue pressure within the bone. The tamping instrument 108 thereby
serves to clear residual material from the cannula instrument 30,
to assure that the desired volume of material is delivered into the
cavity. The removal of residual material from the cannula
instrument 30 by the tamping instrument 108 also prevents seepage
of material into surrounding tissue regions upon removal of the
cannula instrument 30. The tamping instrument 108 also compacts the
material uniformly within the cavity, again without undue pressure.
Further details of these functions and results will be discussed
later.
IV. The Kit
[0106] As FIGS. 1 and 2 show, in the illustrated embodiment, the
kit 12 includes an interior tray 126 made, e.g., from die cut
cardboard, plastic sheet, or thermo-formed plastic material. The
tray 126 includes spaced apart tabs 128, which hold the various
instruments in a secure position during sterilization and storage
prior to use.
[0107] When packaged as a sterile assembly, the kit 12 includes an
inner wrap 130, which is peripherally sealed by heat or the like,
to enclose the tray 126 from contact with the outside environment.
One end of the inner wrap includes a conventional peal-away seal
132, to provide quick access to the tray 126 at the instant of use,
which preferably occurs in a sterile environment, such as within an
operating room.
[0108] When packaged as a sterile assembly, the kit 12 also
includes an outer wrap 134, which is also peripherally sealed by
heat or the like, to enclose the inner wrap 130. One end of the
outer wrap includes a conventional peal-away seal 136, to provide
access to the inner wrap 130 and its contents. The outer wrap 134
can be removed from the inner wrap in anticipation of imminent use,
without compromising sterility of the contents of the kit 12.
[0109] As FIG. 2 shows, each inner and outer wrap 130 and 134
includes a peripherally sealed top sheet 138 and bottom sheet 140.
In the illustrated embodiment, the top sheet 138 is made of
transparent plastic film, like polyethylene or MYLAR7 material, to
allow visual identification of the contents of the kit 12. The
bottom sheet 140 is made from a material that is permeable to ETO
sterilization gas, e.g., TYVEK7 plastic material (available from
DuPont).
[0110] In the illustrated embodiment, the tray 126 presents the
instruments groups 14, 16, and 18 in an ordered, organized layout,
which is arranged to aid the physician in carrying out the intended
procedure. For example, the layout of the tray 126 can present the
instruments groups 14, 16, and 18 in top-to-bottom order, according
to sequence of intended use. For example, in a typical bone access
procedure (as will be demonstrated in greater detail later), the
stylet 22 and stylus 24 of the spinal needle assembly 20 are
deployed first, followed by the guide pin instrument 26, followed
by the obturator instrument 28, then the cannula instrument 30,
then the drill bit instrument 32, then the cavity forming
instrument 76, then the syringe 104 and nozzle 106 instruments, and
lastly the tamping instrument 108. Accordingly, the tray 126
packages these instruments and components in a top-to-bottom order,
with the spinal needle assembly 20 topmost, the guide pin
instrument 26 next, the obturator instrument 28 next, and so on,
with the tamping instrument 108 lowermost on the tray 126.
[0111] In this layout, the handle 60 is packaged to the side of the
access instrument group 14. The tray 126 can include written labels
(not shown) identifying the components contained in the kit 12.
[0112] The kit 12 also preferably includes in the tray 126
directions 144 for using the contents of the kit 12 to carry out a
desired procedure. An exemplary procedure which the directions 144
can describe will be explained later.
[0113] When packaged as a sterile assembly, the directions 144 can
also include the statement "For Single Patient Use Only" (or
comparable language) to affirmatively caution against reuse of the
contents of the kit 12 whose performance characteristics and
efficacy degrade after a single use. The spinal needle assembly 20,
the cavity forming instrument 76, and the material introducing
instruments 104, 106, and 108 should, for these reasons, be used
but a single time and then discarded. The directions 144 also
preferably affirmatively instruct against resterilization of at
least these contents of kit 12, and also instructs the physician to
dispose of at least these contents of the kit 12 upon use in
accordance with applicable biological waste procedures.
[0114] The presence of the instrument groups 14, 16, and 18
packaged in the sterile kit 12 verifies to the physician that the
contents are sterile and have not been subjected to prior use. The
physician is thereby assured that the instrument groups meet
established performance and sterility specifications.
[0115] It should be appreciated that the various instruments
contained in the kit 12 can be packaged into several, smaller
functional kits. For example, a first kit can package the access
instrument group 14, a second kit can package the cavity forming
instrument group 16, and a third kit can package the material
introduction instrument group 18. FIGS. 1 and 2 illustrate one of
many different possible embodiments.
V. Illustrative Use of the System
[0116] The following describes use of the instrument groups 14, 16,
and 18 packaged in the kit 12 in the context of treating bones.
This is because the instruments of the groups 14, 16, and 18 can be
advantageously used for this purpose. Still, it should be
appreciated that one or more of the instrument groups, used alone
or in association with other instruments, can perform other
diagnostic or therapeutic functions in other interior regions of
the body.
[0117] In particular, the instrument groups 14, 16, and 18 will
described with regard to the treatment of human vertebra. It should
be appreciated, however, their use is not limited to human
vertebrae. The instrument groups 14, 16, and 18 can be used in
association with hand-held instruments in the treatment of diverse
human or animal bone types.
[0118] A. The Vertebral Body
[0119] As FIGS. 6 and 7 show, a typical vertebra 146 includes a
vertebral body 148, which extends on the anterior (i.e., front or
chest) side of the vertebra 146. The vertebral body 148 has the
shape of an oval disk. The vertebral body 148 includes an exterior
formed from compact cortical bone 150. The cortical bone 150
encloses an interior volume of reticulated cancellous, or spongy,
bone 152 (also called medullary bone or trabecular bone).
[0120] The spinal cord 154 passes through the spinal canal 156 of
the vertebra 146. The vertebral arch 158 surrounds the spinal canal
156. The pedicles 160 of the vertebral arch 158 adjoin the
vertebral body 148. The spinous process 162 extends from the
posterior of the vertebral arch 158, as do the left and right
transverse processes 164.
[0121] B. Treatment of a Vertebral Body
[0122] During a typical procedure, a patient lies on an operating
table. The patient can lie face down on the table, or on either
side, or at an oblique angle, depending upon the physician's
preference.
[0123] The physician or surgical assistant removes the outer and
inner wraps 130 and 134 of the kit 12, exposing the tray 126 for
use. The physician acquires the spinal needle assembly 20 from the
tray 126. As FIG. 8 shows, the physician introduces the spinal
needle assembly 20 into soft tissue ST in the patient's back. Under
radiologic or CT monitoring, the physician advances the spinal
needle assembly 20 through soft tissue down to and into the
targeted vertebra 146. The physician will typically administer a
local anesthetic, for example, lidocaine, through assembly 20. In
some cases, the physician may prefer other forms of anesthesia.
[0124] The physician directs the spinal needle assembly 20 to
penetrate the cortical bone 150 and the cancellous bone 152 of the
targeted vertebral body 148. Preferably the depth of penetration is
about 60% to 95% of the vertebral body 148.
[0125] FIG. 8 shows gaining access to cancellous bone through the
side of the vertebral body 148, which is called postero-lateral
access. However, access may be indicated through a pedicle 160,
which is called transpedicular access. The type of access is based
upon the objectives of the treatment or for other reasons, based
upon the preference of the physician.
[0126] As FIG. 9 shows, after positioning the spinal needle
assembly 20 in cancellous bone 152, the physician holds the stylus
24 and withdraws the stylet 22. The physician acquires the guide
pin instrument 26 from the tray 126. As FIG. 10 shows, while still
holding the stylus 24, the physician slides the guide pin
instrument 26 through the stylus 24 and into the cancellous bone
152. The physician now removes the stylus 24 (see FIG. 11), leaving
the guide pin instrument 26 deployed within the cancellous bone
152.
[0127] The physician next acquires the obturator instrument 28 and
the handle 60 from the tray 126. The physician slides the obturator
instrument 28 over the guide pin instrument 26, distal end first.
The physician slides the guide pin instrument 26 through the first
passage 72 and the first socket 64 of the handle 60. As FIG. 12
shows, the physician slides the handle 60 along the guide pin
instrument 26 toward the tapered flange 40 of the obturator
instrument 28, until achieving a running slip-fit between the first
socket 64 and the tapered flange 40, in the manner previously
described. The obturator instrument 28 is now ready for use.
[0128] As FIG. 12 shows, the physician makes a small incision I in
the patient's back. The physician twists the handle 60 while
applying longitudinal force to the handle 60. In response, the
surface 38 of the obturator instrument 28 rotates and penetrates
soft tissue ST through the incision I. The physician may also
gently tap the handle 60, or otherwise apply appropriate additional
longitudinal force to the handle 60, to advance the obturator
instrument 28 through the soft tissue along the guide pin
instrument 26 down to the entry site (see FIG. 13). The physician
can also tap the handle 60 with an appropriate striking tool to
advance the surface 30 of the obturator instrument 28 into the side
of the vertebral body 148 to secure its position (as FIG. 13
shows).
[0129] The physician next slides the handle 60 along the guide pin
instrument 26 away from the obturator instrument 28 to disengage
the tapered flange 40 from the first socket 64. The physician then
proceeds to slide the handle 60 completely off the guide pin
instrument 26.
[0130] The physician acquires the cannula instrument 30 from the
tray 126. As FIG. 14 shows, the physician slides the cannula
instrument 30 over the guide pin instrument 26, distal end first,
and, further, over the obturator instrument 28, until contact
between the end surface 48 and soft tissue ST. The physician now
slides the guide pin instrument 26 and obturator instrument 26
through the second passage 74 and second socket 66 of the handle
60. The physician slides the handle 60 toward the tapered fitting
50 of the cannula instrument 30 until a running slip-fit occurs
between the second socket 66 and the tapered fitting 50, as
previously described. The cannula instrument 30 is now ready for
use.
[0131] As FIG. 14 shows, the physician applies appropriate twisting
and longitudinal forces to the handle 60, to rotate and advance the
cannula instrument 30 through soft tissue ST along the obturator
instrument 28. As FIG. 15 shows, when the end surface 48 of the
cannula instrument 30 contacts cortical bone, the physician can
appropriately tap the handle 60 with a striking tool to advance the
end surface into the side of the vertebral body 148 to secure its
position.
[0132] As FIG. 16 shows, the physician now withdraws the obturator
instrument 28, sliding it off the guide pin instrument 26. This
leaves the guide pin instrument 26 and the cannula instrument 30 in
place, as FIG. 17 shows. The physician next slides the handle 60
along the guide pin instrument 26 away from the cannula instrument
30 to disengage the tapered fitting 50 from the second socket 66.
The physician then slides the handle 60 completely off the guide
pin instrument 26.
[0133] The physician now acquires the drill bit instrument 32 from
the tray 126. As FIG. 18 shows, the physician slides the drill bit
instrument 32 over the guide pin instrument 26, distal end first,
through the cannula instrument 30 until contact between the
machined surface 54 and bone tissue occurs. As FIG. 18 also shows,
the physician next leads the guide pin instrument 26 through the
first passage 72 and first socket 64 of the handle 60. The
physician slides the handle 60 along the guide pin instrument 26
toward the tapered flange 56 of the drill bit instrument 32, until
a running slip-fit occurs between the first socket 64 and the
tapered flange 56, as previously described. The drill bit
instrument 32 is now ready for use.
[0134] As shown by FIG. 18, guided by X-ray (or another external
visualizing system), the physician applies appropriate twisting and
longitudinal forces to the handle 60, to rotate and advance the
cutting edge 54 of the drill bit instrument 32 to open a passage
166 (see FIG. 19) through the bone tissue and completely into the
cancellous bone 152. The drilled passage 166 preferable extends no
more than 95% across the vertebral body 148.
[0135] The physician now slides the handle 60 along the guide pin
instrument 26 away from the drill bit instrument 32 to disengage
the tapered flange 56 from the first socket 64. The physician,
further, slides the handle 60 completely off the guide pin
instrument 26. The physician can now remove the drill bit
instrument 32 and the guide pin instrument 26, leaving only the
cannula instrument 30 in place. The passage 166 made by the drill
bit instrument 32 remains. Subcutaneous access to the cancellous
bone 152 has been accomplished.
[0136] The physician can now acquire the cavity forming instrument
from the tray 126. As FIG. 20 shows, the physician can advance the
expandable structure 86 through the cannula instrument 30 and
passage 166 into the interior volume of the vertebral body 148, as
FIG. 21 also shows. The structure 86 is in its normally collapsed
and not expanded condition during deployment. The stylet 96 or 102
is inserted in the lumen 94 of the catheter tube 78 to provide
added stiffness to the structure 86 while being passed through the
cannula instrument 30.
[0137] As shown in phantom lines in FIG. 20, the physician can, if
desired, reconnect the handle 60 to the cannula instrument 30, to
help stabilize the cannula instrument 30 while deploying the
structure 86. The second passage 74 of the handle accommodates the
catheter tube 78 and the structure 86, when collapsed.
[0138] As FIG. 21 shows, the structure 86 is oriented in the
desired way in the passage 166. As before explained, the bent
stylet 102 can aid in this task. Before, during, or after the
orientation process, the stylet 96 or 102 can be withdrawn (as FIG.
21 shows), to open the lumen 94 for use to pass a rinsing liquid or
negative aspiration pressure.
[0139] Sterile liquid is conveyed under pressure from the source 92
through the lumen 88 into the structure 86. As FIG. 22 shows, the
structure 86 expands inside bone. Expansion of the structure 86
compresses cancellous bone 152 in the vertebral body 148.
[0140] The compression forms an interior cavity 168 in the
cancellous bone 152. As FIG. 23 shows, subsequent collapse and
removal of the structure 86 leaves the cavity 168 in a condition to
receive a filling material.
[0141] The compaction of cancellous bone 152 can also exert
interior force upon cortical bone, making it possible to elevate or
push broken and compressed bone back to or near its original
prefracture, or other desired condition.
[0142] Upon formation of the cavity 168, the physician acquires the
syringe 104 and injection nozzle 106 from the kit 12. As FIG. 24
shows, the physician fills the syringe chamber 110 with the desired
volume of filling material 170. As FIG. 25 shows, the physician
attaches the nozzle 106 to the filled syringe 104. As FIG. 26
shows, the physician inserts the nozzle 106 a selected distance
beyond the distal end 36 of the cannula instrument 30 and into the
cavity, guided by the markings 116.
[0143] As shown in phantom lines in FIG. 26, the handle 60 can
remain attached to the cannula instrument 30 to provide stability,
as the second passage 74 of the handle accommodates the nozzle
106.
[0144] As FIG. 27 shows, the physician manually advances the piston
112 to cause the material 170 to flow through and out of the nozzle
106 and into the cavity. As material 170 fills the cavity, the
physician withdraws the nozzle from the cavity and into the cannula
instrument 30. The cannula instrument 30 channels the material 170
flow toward the cavity 168. As FIG. 28 shows, the cement material
170 flows in a stream into the cavity 168.
[0145] If the selected material 170 is bone cement, the cement
material 170 is placed into the syringe chamber 110 shortly after
it is mixed from two materials (e.g., in an external mixing
device), while it is in a low viscosity, relatively free flowing
liquid state, like a thin pancake batter. In time (e.g., about two
minutes after mixing), the consistency of the cement material 170
will change to a substantially putty-like character.
[0146] The physician operates the syringe 104 to expel the cement
material 170 from the chamber, through the nozzle 106, first into
the cavity and then into the cannula instrument 30. Typically, at
the end of the syringe injection process, material 170 should
extend from the cavity and occupy about 40% to 50% of the cannula
instrument 30.
[0147] When a desired volume of cement is expelled from the syringe
104, the physician withdraws the nozzle 106 from the cannula
instrument 30, as FIG. 29 shows. The physician may first rotate the
syringe 104 and nozzle 106, to break loose the material 170 in the
nozzle 106 from the ejected bolus of material 170 occupying the
cannula instrument 30.
[0148] The physician acquires the tamping instrument 108 from the
kit 12. As FIG. 30 shows, the physician advances the tamping
instrument 108 through the cannula instrument 30. As phantom lines
in FIG. 30 show, the handle 60 can remain attached to the cannula
instrument 30 to provide stability, as the second passage 74 of the
handle accommodates the tamping instrument 108.
[0149] The distal end of the tamping instrument 108 contacts the
residual volume of cement material 170 in the cannula instrument
30. As FIGS. 30 and 31 show, advancement of the tamping instrument
108 displaces progressively more of the residual material 170 from
the cannula instrument 30, forcing it into the cavity 168. The flow
of material 170 into the cavity 168, propelled by the advancement
of the tamping instrument 108 in the cannula instrument 30, serves
to uniformly distribute and compact the material 170 inside the
cavity 168, without the application of undue pressure.
[0150] The use of the syringe 104, nozzle 106, and the tamping
instrument 108 allows the physician to exert precise control when
filling the cavity with material 170. The physician can immediately
adjust the volume and rate of delivery according to the particular
local physiological conditions encountered. The application of low
pressure (i.e., no greater than 360 psi), which is uniformly
applied by the syringe 104 and the tamping instrument 108, allows
the physician to respond to fill volume and flow resistance
conditions in a virtually instantaneous fashion. The chance of
overfilling and leakage of material 170 outside the cavity is
significantly reduced.
[0151] When the physician is satisfied that the material 170 has
been amply distributed inside the cavity 168, the physician
withdraws the tamping instrument 108 from the cannula instrument
30. The physician preferably first twists the tamping instrument
108 to cleanly break contact with the material 170. The handle 60
can now be removed and the cannula instrument 30 withdrawn, as FIG.
32 shows. The incision site is sutured closed. The bone treatment
procedure is concluded.
[0152] Eventually the material 170, if cement, will harden a rigid
state within the cavity 168. The capability of the vertebral body
148 to withstand loads is thereby improved.
[0153] The selected material 170 can be an autograft or allograft
bone graft tissue collected in conventional ways. For example, the
graft material can be in paste form, as described by Dick, AUse of
the Acetabular Reamer to Harvest Autogenic Bone Graft Material: A
Simple Method for Producing Bone Paste,@ Archives of Orthopaedic
and Traumatic Surgery (1986), 105: 235-238, or in pellet form, as
described by Bhan et al, APercutaneous Bone Grafting for Nonunion
and Delayed Union of Fractures of the Tibial Shaft,@ International
Orthopaedics (SICOT) (1993) 17: 310-312, both of which are
incorporated herein by reference. Alternatively, the bone graft
tissue can be obtained using a Bone Graft Harvester, which is
commercially available from SpineTech. Using a funnel, the paste or
pellet graft tissue material is loaded into the cannula instrument
30. The tamping instrument 108 is then advanced into the cannula
instrument 30 in the manner previously described, to displace the
paste or pellet graft tissue material out of the cannula instrument
30 and into the cavity.
[0154] The selected material 170 can also comprise a granular bone
material harvested from coral, e.g., ProOsteonJ calcium carbonate
granules, available from Interpore. The granules are loaded into
the cannula instrument 30 using a funnel and advanced into the
cavity using the tamping instrument 108.
[0155] The selected material 170 can also comprise demineralized
bone matrix suspended in glycerol (e.g., GraftonJ allograft
material available from Osteotech), or SRSJ calcium phosphate
cement available from Novian. These viscous materials, like the
bone cement previously described, can be loaded into the syringe
104 and injected into the cavity using the nozzle 106, which is
inserted through the cannula instrument 30 into the cavity. The
tamping instrument 108 is used to displace residual material from
the cannula instrument 30 into the cavity, as before described.
[0156] The selected material 170 can also be in sheet form, e.g.
CollagraftJ material made from calcium carbonate powder and
collagen from bovine bone. The sheet can be rolled into a tube and
loaded by hand into the cannula instrument 30. The tamping
instrument 108 is then advanced through the cannula instrument, to
push and compact the material in the cavity.
VI. Alternative Embodiments
[0157] The use of low pressure delivery of material 170 frees the
system 10 from the need to accommodate relatively large diameter,
high pressure delivery devices. The interior diameter of the
cannula instrument 30 can be downsized accordingly, thereby
minimizing the dimensions of the subcutaneous pathway to gain
access to the targeted bone region.
[0158] Typically, when low pressure material injection instruments
are used, the largest tool that the reduced-diameter cannula
instrument must accommodate is the expandable cavity-forming
structure 82. The structure 82 presents a minimal profile during
deployment, as it can be collapsed and, if desired, a lubricous
coating may also be applied to the exterior of the structure 82 to
facilitate its passage through the reduced-diameter cannula
instrument.
[0159] A. Low Pressure Material Injection Instruments
[0160] FIG. 33 exemplifies low pressure material injection
instruments 180 and 182 that function in association with a cannula
instrument 184 having a reduced interior diameter, e.g. only about
3.4 mm or less.
[0161] One instrument 180 comprises a reduced-diameter nozzle. As
FIG. 33 shows, the nozzle 180 is sized to pass through the
reduced-diameter cannula instrument 184, to thereby pass into bone
in the manner previously shown in FIG. 26. The reduced-diameter
nozzle 180 connects by a threaded connector 186 to the syringe 104.
For material strength, despite its reduced dimension, the nozzle
180 is preferably formed from a rigid metal material, e.g.,
stainless steel.
[0162] As FIG. 33 shows, the reduced-diameter nozzle 180 also
includes measured markings 188 along its length, as previously
described. The markings 188 include a set point 190, as previously
described, which aligns with the proximal end of the cannula
instrument 184 when the distal ends of the cannula instrument 184
and the nozzle 180 align.
[0163] The other reduced diameter instrument 182 comprises a
stylet, which is sized to pass through the interior bore of the
nozzle 180. The stylet 182 includes a handle 192, which rests on
the proximal connector 186 of the nozzle 180 when the stylet 182 is
fully inserted into the nozzle 180. When the handle 192 is rested,
the distal ends of the stylet 182 and nozzle 180 align. The
presence of the stylet 182 inside the nozzle 180 closes the
interior nozzle bore.
[0164] In use, the nozzle 180 is coupled to the syringe 104 and
inserted through the cannula instrument 184 into the
material-receiving cavity 168 formed in cancellous bone, in the
same manner shown in FIG. 26. Material in the syringe 104 is
injected at low pressure through the nozzle 180 into the cavity
168. As before explained, as the cavity 168 progressively fills
with material, the nozzle 180 is withdrawn back into the cannula
instrument 184. Typically, when the injection of material is
completed, material extends from the cavity 168 and occupies about
40% to 50% of the cannula instrument 184.
[0165] At this point, the nozzle 180 can be fully withdrawn from
the cannula instrument 184 and unthreaded from the syringe 104. The
stylet 182 can be advanced into the nozzle 180, to bring the handle
192 at rest against the connector 186, thereby clearing residual
material from the nozzle 180. The nozzle 180 and stylet can then be
inserted as a nested unit into the cannula instrument 184. Nested
together, the nozzle 180 and stylet 182 form a tamping instrument.
Upon advancement through the cannula instrument 184, the nested
nozzle 180 and stylet 182 displace residual material from the
cannula instrument 184 into the cavity 168, in generally the same
manner as previously shown in FIGS. 30 and 31, thereby uniformly
compacting material within the cavity 168 in a controlled fashion
and without undue pressure.
[0166] Alternatively, a single-piece tamping instrument, separate
from the nozzle 180, can be provided, downsized to fit through the
reduced-diameter cannula instrument 184. In this embodiment, the
stylet 182 is not necessary, unless it is desired to reclaim
material from the nozzle.
[0167] B. Cavity Forming Instrument
[0168] FIG. 34 shows a cavity forming instrument 194 intended to be
deployed through the reduced-diameter cannula instrument 184, shown
in FIG. 33. In many respects, the instrument 194 is like the
instrument 76, previously described and shown in FIG. 4A, and
common reference numerals will be assigned to common structural
elements. The instrument 184 includes a flexible catheter tube 78
having a proximal end 80 and a distal end 82. The proximal end 80
carries a handle grip 84, and the distal end 82 carries an
expandable structure 86, which, when deployed in bone, compacts
cancellous bone and forms the cavity 168.
[0169] Unlike the previously-described instrument 76, the
instrument 194 carries an introducer sleeve 196. The introducer
sleeve 196 slides along the catheter tube 78 between the handle
grip 84 and the expandable structure 86. The introducer sleeve 196
includes a tubular main body 198 with a forward collar 200 and a
rear collar 202.
[0170] The introducer sleeve 196 normally occupies an advanced
position on the instrument 194, as shown in FIG. 35. In this
position, the main body 198 overlies and surrounds the expandable
structure 86. The main body 198 is sized to compress the structure
86 to an outside diameter that is slightly less than the interior
diameter of the reduced-diameter cannula instrument 184.
[0171] As FIG. 35 shows, when the introducer sleeve 196 occupies
the advanced position, the forward collar 200 extends beyond the
distal end of the compressed expandable structure 82. As FIG. 36
shows, in this position, the forward collar 200 presents itself for
engagement with the proximal end 204 of the cannula instrument 184.
The forward collar 200 is sized to have an interior diameter that
makes friction-fit engagement about the proximal end 204 of the
cannula instrument 184.
[0172] As FIG. 36 shows, when it is time to deploy the expandable
structure 86 through the cannula instrument 184, the physician
engages the forward collar 200 of the introducer sleeve 196 in a
friction fit about the proximal end 204 of the cannula instrument
184. As FIG. 37 shows, advancing the catheter tube 78 moves the
compressed structure 86 through the main body 198 of the sleeve 196
and into the bore of the cannula instrument 184. The engagement of
the forward collar 200 about the proximal cannula end 204 aligns
the axis of the structure 86 with the axis of the cannula
instrument 184, while compressing the structure 86 to a diameter
smaller than the interior of the cannula instrument 184. Upon
advancement of the catheter tube 78, the introducer sleeve 196
guides the structure 86 into the cannula instrument 194 without
tearing or other damage.
[0173] Once the expandable structure 86 is advanced through the
cannula instrument 184 and into bone, the physician can slide the
introducer sleeve 196 rearward away from the proximal cannula end
204, to break the friction fit between the end 204 and the forward
sleeve. As FIG. 34 shows, the rear collar 202 of the sleeve 196 is
sized to make a snap fit engagement about a stem 206, which
surrounds the catheter tube 78 near the handle 84. The snap fit
engagement stabilizes the position of the sleeve 196 during
subsequent use and manipulation of the cavity-forming instrument
194.
[0174] The features of the invention are set forth in the following
claims.
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