U.S. patent application number 11/528164 was filed with the patent office on 2007-03-08 for methods for treating fractured and/or diseased bone by introduction of a bone filling material.
This patent application is currently assigned to Kyphon Inc.. Invention is credited to Joseph J. Basista, Ryan P. Boucher, Marialulu Follmer, Richard W. Layne, Reynaldo A. Osorio, Mark A. Reiley, Michael L. Reo, Robert M. Scribner, Karen D. Talmadge.
Application Number | 20070055280 11/528164 |
Document ID | / |
Family ID | 22718531 |
Filed Date | 2007-03-08 |
United States Patent
Application |
20070055280 |
Kind Code |
A1 |
Osorio; Reynaldo A. ; et
al. |
March 8, 2007 |
Methods for treating fractured and/or diseased bone by introduction
of a bone filling material
Abstract
A flow path is established into cancellous bone within a
vertebral body through a percutaneous path. A bone filling material
is conveyed into the flow path in a volume and at a pressure that
results in an enlargement of the flow path volume. The enlargement
can create a cavity and/or move a fractured cortical plate of the
vertebral body toward a desired anatomic position. The bone filling
material can comprise, e.g., a bone cement.
Inventors: |
Osorio; Reynaldo A.; (Daly
City, CA) ; Follmer; Marialulu; (Santa Clara, CA)
; Layne; Richard W.; (Palo Alto, CA) ; Boucher;
Ryan P.; (San Francisco, CA) ; Talmadge; Karen
D.; (Palo Alto, CA) ; Basista; Joseph J.;
(Mountain View, CA) ; Reiley; Mark A.; (Piedmont,
CA) ; Scribner; Robert M.; (Los Altos, CA) ;
Reo; Michael L.; (Redwood City, CA) |
Correspondence
Address: |
RYAN KROMHOLZ & MANION, S.C.
POST OFFICE BOX 26618
MILWAUKEE
WI
53226
US
|
Assignee: |
Kyphon Inc.
|
Family ID: |
22718531 |
Appl. No.: |
11/528164 |
Filed: |
September 27, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10783723 |
Feb 20, 2004 |
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11528164 |
Sep 27, 2006 |
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|
09827260 |
Apr 5, 2001 |
6726691 |
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10783723 |
Feb 20, 2004 |
|
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|
10346618 |
Jan 17, 2003 |
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10783723 |
|
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|
09597646 |
Jun 20, 2000 |
6716216 |
|
|
10346618 |
Jan 17, 2003 |
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09134323 |
Aug 14, 1998 |
6241734 |
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09597646 |
Jun 20, 2000 |
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60194685 |
Apr 5, 2000 |
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Current U.S.
Class: |
606/92 |
Current CPC
Class: |
A61F 2/4603 20130101;
A61B 2090/062 20160201; A61B 50/33 20160201; A61F 2002/4662
20130101; A61B 2017/00539 20130101; A61F 2310/00353 20130101; A61F
2/44 20130101; A61F 2002/2835 20130101; A61F 2002/4635 20130101;
A61B 17/8855 20130101; A61F 2/4601 20130101; A61B 17/1671 20130101;
A61F 2002/3008 20130101; A61F 2250/0098 20130101; A61B 90/39
20160201; A61B 2017/00557 20130101; A61B 17/8805 20130101; A61B
2050/0065 20160201; A61F 2002/30581 20130101; A61B 2017/00464
20130101; A61B 2017/00261 20130101; A61B 17/1604 20130101; A61B
17/3472 20130101; A61B 2017/00867 20130101 |
Class at
Publication: |
606/092 |
International
Class: |
A61F 2/00 20060101
A61F002/00 |
Claims
1. A method comprising selecting a vertebral body having an
interior volume occupied, at least in part, by cancellous bone, the
vertebral body having at least one cortical plate that is depressed
due to fracture, establishing a percutaneous path into the
vertebral body, establishing into the cancellous bone through the
percutaneous path a flow path having an initial flow path volume,
and conveying a bone filling material into the flow path in a
volume that exceeds the initial flow path volume and at a pressure
resulting in enlargement of the initial flow path volume to move
the fractured cortical plate toward a desired anatomic
position.
2. A method according to claim 1 wherein conveying the bone filling
material results in enlargement of the initial flow path volume to
move the fractured cortical plate toward a desired pre-fracture
anatomic position
3. A method according to claim 1 wherein the initial volume of the
flow path is established by a tool introduced through the
percutaneous path.
4. A method according to claim 3 wherein the tool comprises an
expandable body.
5. A method according to claim 3 wherein the tool comprises at
least one of a mechanical tamp, reamer, or hole puncher.
6. A method according to claim 1 wherein establishing the initial
flow path volume included compacting cancellous bone.
7. A method according to claim 1 wherein the bone filling material
comprises bone cement.
8. A method according to claim 1 wherein the bone filling material
has a viscosity that resists extravazation into cancellous
bone.
9. A method according to claim 1 wherein the bone filling material
sets to a hardened condition.
10. A method comprising selecting a vertebral body having an
interior volume occupied, at least in part, by cancellous bone,
selecting a flowable bone filling material capable of setting to a
hardened condition, establishing a percutaneous path into the
vertebral body, creating through the percutaneous path a barrier
region of compacted cancellous bone having an initial volume, and
conveying the flowable bone filling material into the barrier
region in a volume that exceeds the initial volume and at a
pressure resulting in creation of a cavity in the cancellous bone
having a volume greater than the initial volume of the barrier
region.
11. A method according to claim 10 further comprising allowing the
bone filling material to set to the hardened condition within the
cavity.
12. A method according to claim 10 wherein the bone filling
material comprises bone cement.
13. A method according to claim 10 wherein the bone filling
material has a viscosity that resists extravazation into cancellous
bone.
Description
RELATED APPLICATIONS
[0001] This application is a divisional of co-pending U.S. patent
application Ser. No. 10/783,723, filed 20 Feb. 2004, and entitled
"Methods and Devices for Treating Fractured and/or Diseased Bone,"
which is a divisional of U.S. patent application Ser. No.
09/827,260, filed 5 Apr. 2001 (now U.S. Pat. No. 6,726,691), which
claims the benefit of U.S. Provisional Patent Application No.
60/194,685, filed 5 Apr. 2000 (Expired), and which is also a
continuation-in-part of co-pending U.S. patent application Ser. No.
10/346,618, filed 17 Jan. 2003, which is a divisional of U.S.
patent application Ser. No. 09/597,646, filed 20 Jun. 2000 (now
U.S. Pat. No. 6,716,216), which is a continuation-in-part of U.S.
patent application Ser. No. 09/134,323, filed 14 Aug. 1998 (now
U.S. Pat. No. 6,241,734), each of which is incorporated herein by
reference.
[0002] This application is also related to the following co-pending
United States patent applications, which are commonly owned and
have been filed on the same day as this application: (1) United
States patent application No. (to be supplied, attorney docket
17207-For Div 12), entitled "Methods For Treating Fractured and/or
Diseased Bone By Introduction Of Different Bone Filling Materials"
(2) United States patent application No. (to be supplied, attorney
docket 17207-For Div 13), entitled "Methods For Treating A
Fractured and/or Diseased Vertebral Body By Incremental
Introduction Of Bone Filling Material."
BACKGROUND OF THE INVENTION
[0003] 1. Field of the Invention
[0004] The present invention relates to devices and methods for
treating fractured and/or diseased bone. More specifically, the
present invention relates to devices and methods for repairing,
reinforcing and/or treating fractured and/or diseased bone using
various devices, including cavity-forming devices.
[0005] 2. Description of the Background
[0006] Normal healthy bone is composed of a framework made of
proteins, collagen and calcium salts. Healthy bone is typically
strong enough to withstand the various stresses experienced by an
individual during his or her normal daily activities, and can
normally withstand much greater stresses for varying lengths of
time before failing. However, osteoporosis or a host of other
diseases, including such diseases as breast cancer, hemangiomas,
osteolytic metastases or spinal myeloma lesions, as well as the
long term excessive use of alcohol, tobacco and/or various drugs,
can affect and significantly weaken healthy bone over time. If
unchecked, such factors can degrade bone strength to a point where
the bone is especially prone to fracture, collapse and/or is unable
to withstand even normal daily stresses.
[0007] Unfortunately, losses in bone strength are often difficult
to discover until bone integrity has already been seriously
compromised. For instance, the effects of osteoporosis are often
not discovered until after a bone fracture has already occurred, at
which time much of the patient's overall bone strength has
typically weakened to dangerous levels. Moreover, as most bone
development occurs primarily during childhood and early adulthood,
long-term losses in bone strength are typically irreversible. In
addition, many bone diseases, including osteoporosis, cancer, and
other bone-related disorders, are not routinely curable at our
current stage of medical development.
[0008] For many individuals in our aging world population,
undiagnosed and/or untreatable bone strength losses have already
weakened these individuals' bones to a point that even normal daily
activities pose a significant threat of fracture. For example, when
the bones of the spine are sufficiently weakened, the compressive
forces in the spine can often cause fracture and/or deformation of
the vertebral bodies. For sufficiently weakened bone, even normal
daily activities like walking down steps or carrying groceries can
cause a collapse of one or more spinal bones, much like a piece of
chalk collapses under the compressive weight of a human foot. A
fracture of the vertebral body in this manner is typically referred
to as a vertebral compression fracture. Researchers estimate that
at least 25 percent of all women, and a somewhat smaller percentage
of men, over the age of 50 will suffer one or more vertebral
compression fractures due to osteoporosis alone. In the United
States, it is estimated that over 700,000 vertebral compression
fractures occur each year, over 200,000 of which require some form
of hospitalization. Other commonly occurring fractures resulting
from weakened bones can include hip, wrist, knee and ankle
fractures, to name a few.
[0009] Fractures such as vertebral compression fractures often
result in episodes of pain that are chronic and intense. Aside from
the pain caused by the fracture itself, the involvement of the
spinal column can result in pinched and/or damaged nerves, causing
paralysis, loss of function, and intense pain which radiates
throughout the patient's body. Even where nerves are not affected,
however, the intense pain associated with all types of fractures is
debilitating, resulting in a great deal of stress, impaired
mobility and other long-term consequences. For example, progressive
spinal fractures can, over time, cause serious deformation of the
spine ("kyphosis"), giving an individual a hunched-back appearance,
and can also result in significantly reduced lung capacity and
increased mortality.
[0010] Until recently, treatment options for vertebral compression
fractures, as well as other serious fractures and/or losses in bone
strength, were extremely limited--mainly pain management with
strong oral or intravenous medications, reduced activity, bracing
and/or radiation therapy, all with mediocre results. Because
patients with these problems are typically older, and often suffer
from various other significant health complications, many of these
individuals are unable to tolerate invasive surgery. In addition,
to curb further loss of bone strength, many patients are given
hormones and/or vitamin/mineral supplements--again with mediocre
results and often with significant side effects.
[0011] Over the past decade, a technique called vertebroplasty has
been introduced into the United States. Vertebroplasty involves the
injection of a flowable reinforcing material, usually
polymethylmethacrylate (PMMA--commonly known as bone cement), into
a fractured, weakened, or diseased vertebral body. Shortly after
injection, the liquid filling material hardens or polymerizes,
desirably supporting the vertebral body internally, alleviating
pain and preventing further collapse of the injected vertebral
body.
[0012] While vertebroplasty has been shown to reduce some pain
associated with vertebral compression fractures, this procedure has
certain inherent drawbacks. The most significant danger associated
with vertebroplasty is the inability of the practitioner to control
the flow of liquid bone cement during injection into a vertebral
body. Although the location and flow patterns of the cement can be
monitored by CT scanning or x-ray fluoroscopy, once the liquid
cement exits the injection needle, it naturally follows the path of
least resistance within the bone, which is often through the cracks
and/or gaps in the cancellous and/or cortical bone. Moreover,
because the cancellous bone resists the injection of the bone
cement and small diameter needles are typically used in
vertebroplasty procedures, extremely high pressures are required to
force the bone cement through the needle and into the vertebral
body. Bone cement, which is viscous, is difficult to inject through
small diameter needles, and thus many practitioners choose to "thin
out" the cement mixture to improve cement injection, which
ultimately exacerbates the leakage problems. In a recent study
where 37 patients with bone metastases or multiple myeloma were
treated with vertebroplasty, 72.5% of the procedures resulted in
leakage of the cement outside the vertebral body. Cortet B. et al.,
Percutaneous Vertebroplasty in Patients With Osteolytic Metastases
or Multiple Myeloma (1998). Moreover, where the practitioner
attempts to "thin out" the cement by adding additional liquid
monomer to the cement mix, the amount of unpolymerized or "free"
monomer increases, which can ultimately be toxic to the
patient.
[0013] Another drawback of vertebroplasty is due to the inability
to visualize (using CT scanning or x-ray fluoroscopy) the various
venous and other soft tissue structures existent within the
vertebra. While the position of the needle within the vertebral
body is typically visualized, the location of the venous structures
within the vertebral body are not. Accordingly, a small diameter
vertebroplasty needle can easily be accidentally positioned within
a vein in the vertebral body, and liquid cement pumped directly
into the venous system, where the cement easily passes out the
anterior and/or posterior walls of the vertebrae through the
anterior external venous plexus or the basivertebral vein.
[0014] Another significant drawback inherent in vertebroplasty is
the inability of this procedure to restore the vertebral body to a
pre-fractured condition prior to the injection of the reinforcing
material. Because the bone is fractured and/or deformed, and not
repositioned prior to the injection of cement, vertebroplasty
essentially "freezes" the bone in its fractured condition.
Moreover, it is highly unlikely that a traditional vertebroplasty
procedure could be capable of restoring significant pre-fracture
anatomy--because bone cement flows towards the path of least
resistance, any en-masse movement of the cortical bone would likely
create gaps in the interior and/or walls of the vertebral body
through which the bone cement would then immediately flow.
[0015] A more recently developed procedure for treating fractures
such as vertebral compression fractures and other bone-related
disorders is known as Kyphoplasty.TM.. See, for example, U.S. Pat.
Nos. 4,969,888 and 5,108,404. In Kyphoplasty, an expandable body is
inserted through a small opening in the fractured or weakened bone,
and then expanded within the bone. This procedure compresses the
cancellous bone, and desirably moves the fractured bone to its
pre-fractured orientation, creating a cavity within the bone that
can be filled with a settable material such as cement or any number
of synthetic bone substitutes. In effect, the procedure "sets" the
bone at or near its pre-fracture position and creates an internal
"cast," protecting the bone from further fracture and/or collapse.
This procedure is of course suitable for use in various other bones
as well.
[0016] While Kyphoplasty can restore bones to a pre-fractured
condition, and injected bone filler is less likely to leak out of
the vertebral body during a Kyphoplasty procedure, Kyphoplasty
requires a greater number of surgical tools than a vertebroplasty
procedure, at an increased cost. Moreover, Kyphoplasty tools are
typically larger in diameter than vertebroplasty tools, and thus
require larger incisions and are generally more invasive.
SUMMARY OF THE INVENTION
[0017] The present invention overcomes many of the problems and
disadvantages associated with current strategies and designs in
medical procedures to repair, reinforce and/or treat weakened,
diseased and/or fractured bone.
[0018] The invention provides a method including establishment of a
flow path into cancellous bone within a vertebral body through a
percutaneous path. A bone filling material is conveyed into the
flow path in a volume and at a pressure that results in an
enlargement of the flow path volume. The enlargement can create a
cavity and/or move a fractured cortical plate of the vertebral body
toward a desired anatomic position. The bone filling material can
comprise, e.g., a bone cement.
[0019] One aspect of the invention provides a method that selects
for treatment a vertebral body having an interior volume occupied,
at least in part, by cancellous bone, which vertebral body has at
least one cortical plate that is depressed due to fracture. The
method establishes a percutaneous path into the vertebral body, and
establishes into the cancellous bone through the percutaneous path
a flow path having an initial flow path volume. The method conveys
a bone filling material into the flow path in a volume that exceeds
the initial flow path volume and at a pressure resulting in
enlargement of the initial flow path volume to move the fractured
cortical plate toward a desired anatomic position. The bone filling
material can comprise, e.g., a bone cement.
[0020] In one embodiment, the initial volume of the flow path is
established by a tool introduced through the percutaneous path. The
tool can comprise, e.g., an expandable body or at least one of a
mechanical tamp, reamer, or hole puncher.
[0021] Another aspect of the invention provides a method that
selects for treatment a vertebral body having an interior volume
occupied, at least in part, by cancellous bone. The method selects
a flowable bone filling material capable of setting to a hardened
condition. The method establishes a percutaneous path into the
vertebral body and creates through the percutaneous path a barrier
region of compacted cancellous bone having an initial volume. The
method conveys the flowable bone filling material into the barrier
region in a volume that exceeds the initial volume and at a
pressure resulting in creation of a cavity in the cancellous bone
having a volume greater than the initial volume of the barrier
region. The bone filling material can comprise, e.g., a bone
cement.
[0022] Other objects, advantages, and embodiments of the invention
are set forth in part in the description which follows, and in
part, will be obvious from this description, or may be learned from
the practice of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is a diagram of a spine with a compression fracture
in one vertebrae;
[0024] FIG. 2 is a diagram of a patient about to undergo
surgery;
[0025] FIG. 3 is a lateral view, partially broken away and in
section, of a lumbar vertebra depicting a compression fracture;
[0026] FIG. 4 is a coronal view of a lumbar vertebra;
[0027] FIG. 5A is a lateral view of a lumbar vertebra depicting a
spinal needle inserted into the vertebral body;
[0028] FIG. 5B is a lateral view of the lumbar vertebra of FIG. 5A,
with the stylet removed from the spinal needle;
[0029] FIG. 5C is a lateral view of the lumbar vertebra of FIG. 5B,
with a cavity-forming device constructed in accordance with one
embodiment of the present invention inserted into the vertebral
body;
[0030] FIG. 5D is a lateral view of the lumbar vertebra of FIG. 5C,
with the cavity-forming device inflated;
[0031] FIG. 5E is a lateral view of the lumbar vertebra of FIG. 5D,
with the cavity-forming device deflated;
[0032] FIG. 5F is a lateral view of the lumbar vertebra of FIG. 5E,
with the cavity-forming device removed from the vertebral body;
[0033] FIG. 5G is a lateral view of the lumbar vertebra of FIG. 5F,
with a bone filler injected into the vertebral body;
[0034] FIG. 5H is a lateral view of the lumbar vertebra of FIG. 5G,
with the spinal needle advanced into the cavity;
[0035] FIG. 5I is a lateral view of the lumbar vertebra of FIG. 5H,
with a second bone filler injected into the vertebral body;
[0036] FIG. 5J is a lateral view of the lumbar vertebra of FIG. 5I,
with additional bone filler injected into the vertebral body;
[0037] FIG. 5K is a lateral view of the lumbar vertebra of FIG. 5J,
with additional bone filler injected into the vertebral body;
[0038] FIG. 5L is a lateral view of the lumbar vertebra of FIG. 5K,
with the spinal needle removed from vertebral body;
[0039] FIG. 6A is a side view of a cavity-forming device
constructed in accordance with an alternate embodiment of the
present invention;
[0040] FIG. 6B is a close-up view of the distal end of the
cavity-forming device of FIG. 6A;
[0041] FIG. 7A is a lateral view of a lumbar vertebra, depicting
the cavity-forming device of FIG. 6A being inserted into the
vertebra;
[0042] FIG. 7B is a lateral view of the lumbar vertebra of FIG. 7A,
with the cavity-forming device deployed within the vertebra;
[0043] FIG. 7C is a lateral view of the lumbar vertebra of FIG. 7B,
with the cavity-forming device withdrawn from the vertebra;
[0044] FIG. 8A is a lateral view of a lumbar vertebra, depicting an
alternate procedure for treating a vertebral body in accordance
with the teachings of the present invention;
[0045] FIG. 8B is a lateral view of the lumbar vertebra of FIG. 8A,
with a cavity-forming device inserted into the bone filler;
[0046] FIG. 8C is a lateral view of the lumbar vertebra of FIG. 8B,
with the cavity-forming device expanded in the cavity;
[0047] FIG. 9 is a side view of a cavity-forming device constructed
in accordance with one embodiment of the present invention;
[0048] FIG. 10 is a close-up view of the distal end of a
cavity-forming device of FIG. 9;
[0049] FIG. 11 is a close-up view of the distal end of a balloon
catheter protruding from the distal end of a needle, depicting the
inflation of the balloon material with an inflation medium;
[0050] FIG. 12 is a side view of a cavity-forming device
constructed in accordance with an alternate embodiment of the
present invention;
[0051] FIG. 13 is a side view of a cavity-forming device
constructed in accordance with another alternate embodiment of the
present invention;
[0052] FIG. 14 is a side view of a cavity-forming device
constructed in accordance with another alternate embodiment of the
present invention;
[0053] FIG. 15 is a side view of a cavity-forming device
constructed in accordance with another alternate embodiment of the
present invention;
[0054] FIG. 16A is a lateral view of a lumbar vertebra, depicting
an alternate procedure for treating a vertebral body in accordance
with the teachings of the present invention;
[0055] FIG. 16B is a lateral view of the lumbar vertebra of FIG.
16A, with bone filler injected into the vertebra;
[0056] FIG. 16C is a lateral view of the lumbar vertebra of FIG.
16B, with a cavity-forming device inserted into the vertebra;
[0057] FIG. 16D is a lateral view of the lumbar vertebra of FIG.
16C, with the cavity-forming device expanded in the cavity;
[0058] FIG. 17 is a side view of a cavity-forming device
constructed in accordance with another alternate embodiment of the
present invention;
[0059] FIG. 18 is a side view of a cavity-forming device
constructed in accordance with another alternate embodiment of the
present invention;
[0060] FIG. 19 is a cross-sectional view of the cavity-forming
device of FIG. 18, taken along line 19-19; and
[0061] FIG. 20 is a cross-sectional view of the cavity-forming
device of FIG. 18, taken along line 20-20.
DESCRIPTION OF THE INVENTION
[0062] As embodied and broadly described herein, the present
invention is directed to surgical methods for repairing,
reinforcing and/or treating weakened, diseased and/or fractured
bone. The present invention is further directed to various devices
for facilitating such surgical methods.
[0063] FIG. 1 depicts a typical human spine 1, in which a
compression fracture 10 has occurred in a lumbar vertebra 100. As
best shown in FIG. 3, vertebra 100 has fractured, with the top and
bottom plates 103 and 104 depressing generally towards the anterior
wall 10 of the vertebra 100 and away from their pre-fracture,
normally parallel orientation (indicated generally as parallel
lines 90).
[0064] FIG. 4 depicts a coronal (top) view of the vertebra of FIG.
3. Vertebra 100 includes a vertebral body 105, which extends on the
anterior (i.e. front or chest) side of the vertebra 100. Vertebral
body 105 is approximately the shape of an oval disk, with an
anterior wall 10 and a posterior wall 261. The geometry of the
vertebral body 105 is generally symmetric. Vertebral body 105
includes an exterior formed from compact cortical bone 110. The
cortical bone 110 encloses an interior volume of reticulated
cancellous, or spongy, bone 115 (also called medullar bone or
trabecular bone).
[0065] The spinal canal 150 is located on the posterior (i.e. back)
side of each vertebra 100. The spinal cord 151 passes through the
spinal canal 150. A vertebral arch 135 surrounds the spinal canal
150. Left and right pedicles 120 of the vertebral arch 135 adjoin
the vertebral body 105. The spinous process 130 extends from the
posterior of the vertebral arch 135, as do the left and right
transverse processes 125 and the mamillary processes 126.
[0066] FIG. 2 depicts a patient 50 prepared for disclosed methods
of the present invention. These procedures can be performed on an
outpatient or inpatient basis by a medical professional properly
trained and qualified to perform the disclosed procedures.
Desirably, the patient will be placed under general or local
anesthetic for the duration of the surgical procedures.
[0067] In one embodiment of the present invention, a surgical
method comprises inserting an insertion device 350 (see FIG. 5A)
percutaneously into the bone, such as a fractured vertebral body
105 through, preferably, a targeted area of the back, depicted as
60 in FIG. 2. The insertion device 350 may be any type and size of
hollow instrument, preferably having a sharp end. In one preferred
embodiment, the insertion device 350 comprises a hollow needle of
approximately eleven gauge diameter. An eleven gauge needle is
preferred for the procedure because it incorporates a hollow lumen
of sufficient size to permit the passage of various instruments and
materials, yet the overall size of the needle is small enough to
minimize bone and tissue damage in the patient. It should be
understood, however, that various other size needle assemblies,
including needles of six to 14 gage, could be used with the devices
and methods of the present invention, with varying results. In
addition, various other access instruments, such as those described
in U.S. Pat. Nos. 4,969,888, 5,108,404, 5,827,289, 5,972,015,
6,048,346 and 6,066,154, each of which are incorporated herein by
reference, could be used in accordance with the teachings of the
present invention, with varying results.
[0068] The insertion device 350 is preferably comprised of a
strong, non-reactive, and medical grade material such as surgical
steel. If desired, the insertion device 350 is attached to a
manipulating assembly which is comprised of a non-reactive and
medical grade material including, but not limited to,
acrylonitrile-butadiene-styrene (ABS), polyethylene, polypropylene,
polyurethane, Teflon, or surgical steel. FIG. 5A depicts a
commercially available needle assembly typically used with various
embodiments of the present invention, which are further described
below.
[0069] As shown in FIG. 5A, an insertion device 350, such as an
eleven gauge biopsy needle (commercially available from Becton
Dickinson & Co of Franklin Lakes, N.J.) can be inserted through
soft tissues of the back and into the vertebral body 105.
Generally, the approach for such a procedure will be
transpedicular, although various other approaches, including
lateral, extrapedicular and/or anterior approaches, could be used,
depending upon the level treated and/or intervening anatomical
features well known to those of ordinary skill in the art. In one
embodiment, the device 350 comprises a needle body 348 and a stylet
349, as is well known in the art. During insertion of the device
350, the location of the device 350 is desirably monitored using
visualization equipment such as real-time X-Ray, CT scanning
equipment 70 (see FIG. 2), MRI, or any other monitoring equipment
commonly used by those of skill in the art, including computer
aided guidance and mapping equipment such as the systems
commercially available from BrainLab Corporation or General
Electric Corporation.
[0070] In one preferred embodiment, the distal end 351 of the
insertion device 350 is positioned in the vertebral body 105,
preferably at a location towards the posterior side of the
vertebral body 105. If desired, the distal end 351 could be
positioned in various locations throughout the vertebral body 105,
including towards the anterior side. Once in position, the stylet
349 of the insertion device 350 may be removed, see FIG. 5B, and a
cavity-forming device 200 may be inserted through the shaft 348 and
into the vertebral body 105. See FIG. 5C. The cavity-forming device
200, which is desirably comprised of a biologically compatible and
medically acceptable material, can be a small mechanical tamp,
reamer, hole punch, balloon catheter (as described below) or any
appropriate device which is capable of displacing cancellous bone.
Once the cavity-forming device is positioned within the vertebral
body 105, it is used to displace cancellous bone 115, thereby
creating a cavity 170. See FIG. 5F.
[0071] In one embodiment, shown in FIGS. 9 and 10, the
cavity-forming device comprises a balloon catheter 200. The balloon
catheter 200 desirably extends across at least 20% of the vertebral
body, but could extend greater or lesser amounts, depending upon
the desired size of the cavity to be produced. In this embodiment,
as the balloon catheter 201 is expanded, cancellous bone is
displaced generally outward from the cavity 170 in a controlled
manner, desirably forming a compressed-bone region 172 around a
substantial portion of the outer periphery of the cavity 170.
[0072] The balloon catheter 200, which will be described in more
detail below, is sized or folded to fit through the hollow interior
of the shaft 348 and into a vertebral body 105. Once in a desired
position within the vertebral body 105, the balloon catheter 190 is
filled with a pressurized filling medium 275 appropriate for use in
medical applications including, but not limited to, air, nitrogen,
saline or water. See FIGS. 5D and 11. In a preferred embodiment,
the filling medium 275 is a radiopaque fluid (such as Conray.RTM.
fluid available commercially from Mallinkrodt, Inc., of St. Louis,
Mo.), which allows the physician to visualize the catheter 190
during inflation. If desired, alternate ways of expanding the
catheter, including mechanical expanders, jacks, expanding springs
and/or expanding/foaming agents, could be used, with varying
results.
[0073] In one embodiment, the catheter 201 is expanded to any
appropriate volume which creates a cavity 170 within the vertebral
body 105. In a preferred embodiment, the catheter 201 is expanded
to at least 0.20 cc in volume, but could be expanded to
significantly greater sizes, such as 1, 2, 4, 6 or 8 cc, depending
upon bone quality and density. After cavity creation, the catheter
201 is deflated (see FIG. 5E) and removed from the vertebral body
105 and shaft 348 (see FIG. 5F). Bone filler 180 is introduced
through the shaft 348 and into the vertebral body 105 using any
type of plunger, extruder and/or feed line assembly 349 compatible
with the needle body 348. Once injection of bone filler is
complete, the shaft 348 can be withdrawn.
[0074] If desired, a portion of the balloon catheter 201 could be
temporarily or permanently left within a vertebral body 105. For
example, after cavity formation and removal of the inflation
medium, the deflated expanded section of the balloon catheter 201
could be refilled with bone filler 180 and left within the
vertebral body 105. Alternatively, the inflation medium 275 could
comprise bone filler 180. After the balloon catheter 201 is filled
with such an inflation medium, at least a portion of the catheter
201 could be left permanently within the cavity 170. In an
alternate embodiment, the catheter 201 which is intended to remain
with the cavity 170 could comprise a bio-absorbable material and/or
fabric/mesh material as the expandable structure.
[0075] In creating the cavity 170, the inflation of the catheter
201 causes the expandable material 210 to press against the
cancellous bone 115 which may form a compressed bone region or
"shell" 172 along much of the periphery of the cavity 170. This
shell 172 will desirably inhibit or prevent bone filler 180 from
exiting the cavity 170, thereby inhibiting extravazation of the
bone filler and/or facilitating pressurization of the bone filler
180, if desired, within the cavity. As the pressure in the cavity
170 increases, the walls of the cavity 170 will desirably be forced
further outward by the bone filler 180, compressing additional
cancellous bone within the vertebral body 105 and/or increasing the
size of the cavity 170. If sufficient pressure is available, and
integrity of the shell 172 can be maintained without significant
leakage of bone filler 180, pressures capable of moving fractured
cortical bone can be developed.
[0076] In one embodiment of the present invention, after cavity
formation, an amount of a material, such as a bone filler 180, is
introduced through the shaft 348 into the vertebral body 105 under
low pressure. The amount of bone filler will desirably be more than
the volume of the cavity 170, however, less bone filler may be
introduced with varying results. Once the cavity 170 is
substantially filled, the continued introduction of bone filler 180
will desirably pressurize the bone filler 180 in the cavity 170
such that the increased pressure will cause at least a portion of
the walls of the cavity to move outward, thereby enlarging the
cavity 170 and further compressing cancellous bone and/or moving
cortical bone. Desirably, introduction of the bone filler 180 will
continue until bone filler leak from the vertebral body appears
imminent, the cortical bone has regain its pre-fractured position
and/or the practitioner determines that sufficient bone filler 180
has been injected into the bone. If desired, the physician can
utilize the cavity-forming device to create additional cavities for
bone filler, or the shaft 348 can be removed from the vertebral
body to completed the procedure.
[0077] The bone filler 180 could be any appropriate filling
material used in orthopedic surgery, including, but not limited to,
allograft or autograft tissue, hydroxyapatite, epoxy, PMMA bone
cement, or synthetic bone substitutes such Osteoset.RTM. from
Wright Medical Technology, medical grade plaster of paris, Skeletal
Repair System (SRS.RTM.) cement from Norian Corporation, or
Collagraft from Zimmer. As bone filler 180 is introduced into the
vertebral body 105, the introduction is desirably monitored by
x-ray fluoroscopy, or any other appropriate monitoring device or
method, to ensure that bone filler 180 does not flow outside of the
vertebral body 105. To facilitate visualization, the bone filler
180 may be mixed with a fluoroscopic agent, such as radio opaque
barium sulfate. In another embodiment, the bone filler 180 could
comprise a mixture of bone cement and a thixotropic material which
desirably limits and/or prevents extravazation of the bone
cement.
[0078] In an alternate embodiment of the disclosed method, shown in
FIGS. 5G through 5L, a first bone filler 180 is introduced into the
cavity 170, the amount of first bone filler 180 being desirably
less than or approximately equal to the volume of the cavity 170.
For example, if the balloon catheter 200 utilized to create the
cavity 170 was inflated with 1.0 cc of inflation fluid, then less
than or approximately 1.0 cc of bone filler 180 will initially be
injected into the cavity 170. Of course, if desired, an amount of
first bone filler 180 greater than the cavity volume could be
injected into the cavity. The shaft 348 is then repositioned within
the vertebral body 105, see FIG. 5H, with the distal end 351 of the
device 350 desirably located within the bolus 400 of first bone
filler 180 contained in the cavity 170. As best shown in FIG. 5I, a
second amount of bone filler 182 is then injected into the
vertebral body 105, which desirably forces the first amount of bone
filler 180 outward against the walls of the cavity 170. Desirably,
the first amount of bone filler 180 will resist extravazating out
of the cavity 170 and will push outward against the walls of the
cavity 170, further compressing the cancellous bone 115 and/or
increasing the size of the cavity 170. Introduction of the second
amount of bone filler 182 will desirably continue until bone filler
leak from the vertebral body appears imminent, the cortical bone
has regained its pre-fractured position, and/or the practitioner
determines that sufficient bone filler 180 has been injected into
the bone. If desired, the physician could reinsert a catheter 200
to create an additional cavity, or the shaft 348 can be removed to
complete the procedure.
[0079] FIGS. 8A through 8C depict an alternate embodiment of the
disclosed method, in which the practitioner introduces a first
material, such as a bone filler 180, into the cavity 170, and
subsequently inserts a cavity-forming device 200 into the bone. The
cavity-forming device 200 is then expanded, and desirably
compresses the bone filler 180 against the walls of the cavity,
sealing any significant cracks and/or venous passages through which
the cement will flow. In one further embodiment, a practitioner may
wait to allow the first bone filler to harden partially or fully
prior to removing the cavity-forming device and/or prior to
introducing a second material, such as a bone filler. The second
material (not shown) can subsequently be injected into the
vertebral body with little fear of leakage. If desired, this method
could be utilized whenever cement leakage appears imminent, and can
be repeated multiple times until the practitioner determines that
sufficient bone filler 180 has been injected into the bone. In
addition, the practitioner could repeat this procedure until the
cortical bone has regained its pre-fractured position. In an
alternate embodiment, the practitioner could utilize a
cavity-forming device prior to the introduction of the first bone
filler, and then introduce the first bone filler into the cavity,
subsequently follow one or more of the described methods.
[0080] The first bone filler will desirably comprise a material
that can be introduced into the cavity, but which will resist
extravazation out of the cavity and/or vertebral body when the
second bone filler is injected into the cavity. In one embodiment
of the invention, the first and second bone fillers comprise bone
cement, with the first bone cement being more resistant to
extravazation than the second bone cement. For example, the
ingredients of the first bone cement could be specifically tailored
such that the first bone cement cures faster than the second bone
cement. Alternatively, the first bone cement could be prepared
and/or introduced into the vertebral body before the second bone
cement, allowing the first bone cement to partially or fully cure
before the second bone cement. Alternatively, the curing and/or
hardening of the first bone cement could be accelerated (by
applying heat, for example) or curing and/or hardening of the
second bone cement could be retarded (by cooling, for example). In
another embodiment, the first and second bone fillers comprise bone
cement, with the first bone cement desirably being more viscous
than the second bone cement. In another alternate embodiment, the
first bone filler comprises an expandable structure, such as a
stent.
[0081] In another embodiment, the first bone filler comprises a
material more viscous than the second bone filler, the first and
second bone fillers comprising different materials. In another
embodiment, the first bone filler comprises a material which is
more resistant to extravazation into the cancellous bone than the
second bone filler. In another embodiment, the first bone filler
comprises a material having particles generally larger than
particles in the second bone filler. In a further embodiment, the
particles of the first bone filler are generally larger than the
average pore size within the cancellous bone. In another
embodiment, the first bone filler comprises a settable material,
such as a two-part polyurethane material or other curable
bio-material.
[0082] FIGS. 16A through 16D depict an alternate embodiment of the
disclosed method, in which a first material, such as a bone filler
180, is initially introduced into the cancellous bone 115 of a
human bone, such as a vertebral body 105. An expandable structure
210, such as that found at the distal end of a balloon catheter
200, is subsequently inserted into the vertebral body 105. The
expandable structure 210 is then expanded, which displaces the bone
filler 180 and/or cancellous bone 115, creating a cavity 170 within
the vertebral body 105. In one embodiment, the expansion of the
expandable structure 210 forces the bone filler 180 further into
the cancellous bone 115, and/or further compresses cancellous bone.
To minimize bone filler 180 leakage, the bone filler may be allowed
to partially or completely harden prior to expansion of the
expandable structure 210. Alternatively, the expandable structure
210 may be expanded, and the bone filler 180 allowed to partially
or completely harden around the expandable structure 210. In either
case, a second material, optionally additional bone filler, may be
introduced into the cavity 170. In one embodiment, the second
material is a material which supports the bone in a resting
position. This method may be utilized whenever cement leakage
appears imminent, and may be repeated multiple times until the
practitioner determines that sufficient amounts and varieties of
material have been introduced into the bone. Alternatively, the
practitioner could halt introduction of filler material when the
cortical bone regains or approximates its pre-fractured
position.
[0083] By creating cavities and/or preferred flowpaths within the
cancellous bone, the present invention obviates the need for
extremely high pressure injection of bone filler into the
cancellous bone. If desired, the bone filler could be injected into
the bone at or near atmospheric and/or ambient pressures, or at
pressures less than approximately 400 pounds per square inch, using
bone filler delivery systems such as those described in co-pending
U.S. patent application Ser. No. 09/134,323, which is incorporated
herein by reference. Thus, more viscous bone fillers (such as, for
example, thicker bone cement) can be injected into the bone under
low pressures (such as, for example, exiting the delivery device at
a delivery pressure at or near ambient or atmospheric pressure),
reducing opportunities for cement leakage and/or extravazation
outside of the bone.
CAVITY-FORMING DEVICES
[0084] The present invention also includes cavity-forming devices
constructed in accordance with the teachings of the disclosed
invention. In one embodiment, the cavity-forming device comprises a
balloon catheter 201, as shown in FIGS. 9, 10, and 11. The catheter
comprises a hollow tube 205, which is desirably comprised of a
medical grade material such as plastic or stainless steel. The
distal end 206 of the hollow tube 205 is surrounded by an
expandable material 210 comprised of a flexible material such as
commonly used for balloon catheters including, but not limited to,
metal, plastics, composite materials, polyethylene, mylar, rubber
or polyurethane. One or more openings 250 are disposed in the tube
205 near the distal end 206, desirably permitting fluid
communication between the hollow interior of the tube 205 and the
lumen formed between the tube 205 and the expandable structure 210.
A fitting 220, having one or more inflation ports 222, 224, is
secured to the proximal end 207 of the tube 205. In this
embodiment, once the catheter 201 is in its desired position within
the vertebral body 105, an inflation medium 275 is introduced into
the fitting 220 through the inflation port 222, where it travels
through the fitting 220, through the hollow tube 205, through the
opening(s) 250 and into the lumen 274 between the expandable
structure 210 and the hollow tube 205. As injection of the
inflation medium 275 continues, the pressure of the inflation
medium 275 forces the expandable structure 210 away from the hollow
tube 205, inflating it outward and thereby compressing cancellous
bone 115 and forming a cavity 170. Once a desired cavity size is
reached, the inflation medium 275 is withdrawn from the catheter
200, the expandable structure collapses within the cavity 170, and
the catheter 200 may be withdrawn.
[0085] For example, a balloon catheter 201 constructed in
accordance with one preferred embodiment of the present invention,
suitable for use with an 11-gauge needle, would comprise a hollow
stainless steel hypodermic tube 205, having an outer diameter of
0.035 inches and a length of 10.75 inches. One or more openings 250
are formed approximately 0.25 inches from the distal end of the
tube 205. In a preferred embodiment, the distal end 206 of the
hollow tube 205 is sealed closed using any means well known in the
art, including adhesive (for example, UV 198-M adhesive
commercially available from Dymax Corporation--cured for
approximately 15 minutes under UV light).
[0086] In one embodiment, the hollow tube 205 is substantially
surrounded by an expandable structure 210 comprising an extruded
tube of polyurethane (for example, TEXIN.RTM. 5290 polyurethane,
available commercially from Bayer Corporation). In one embodiment,
the polyurethane tube has an inner diameter of 0.046 inches, an
outer diameter of 0.082 inches, and a length of 9-1/2 inches. The
distal end of the polyurethane tube is bonded to the distal end 206
of the hollow tube 205 by means known in the art, such as by a
suitable adhesive (for example, UV 198-M adhesive). Alternatively,
the polyurethane tube may be heat sealed about the distal end 206
of the hollow tube 205 by means well known in the art. A 3/4 inch
long piece of heat shrink tubing 215 (commercially available from
Raychem Corporation), having a 3/16 inch outer diameter, may be
secured around the proximal end of the polyurethane tubing. In one
embodiment, the proximal end of the hollow tubing 205 is inserted
into the fitting 220 and the heat shrink tubing 215 is desirably
bonded into the fitting 220 using a suitable adhesive known in the
art, such as UV 198-M. The fitting 220, which may be a Luer
T-fitting, commercially available from numerous parts suppliers,
may be made of any appropriate material known to those of skill in
the art. The fitting 220 comprises one or more ports 222, 224 for
attachment to additional instruments, such as pumps and syringes
(not shown). If desired, the hollow tube 205 can similarly be
bonded into the fitting 220 using a suitable adhesive.
Alternatively, as shown in FIG. 12, the expandable structure 210
could be significantly shorter than the hollow tube 205 and be
bonded at its distal end 206 and its proximal end 209 to the hollow
tube 205.
[0087] The hollow tube 205 and one or more openings 250 facilitate
the withdrawal of inflation medium from the catheter during the
disclosed procedures. When a catheter is deflated, the expandable
structure 210 will normally collapse against the tube 205, which
can often seal closed the lumen (in the absence of at least one
secondary withdrawal path) and inhibit further withdrawal of
inflation medium from the expanded structure 210 of a catheter.
However, in an embodiment of the disclosed invention, the one or
more openings 250 near the distal end of the tube 205 allow
inflation medium 275 to be drawn through the hollow hypodermic tube
205, further deflating the expandable structure 210. The strong
walls of the hollow hypodermic tube 205 resist collapsing under the
vacuum which evacuates the inflation medium, maintaining a flowpath
for the inflation medium and allowing the inflation medium to be
quickly drawn out of the catheter, which desirably permits
deflation of the catheter in only a few seconds.
[0088] In the disclosed embodiment, as the catheter 201 is
inflated, the inflation medium 275 will typically seek to fill the
entire lumen between the expandable structure 210 and the hollow
tube 205, thus expanding the catheter 201 along the entire length
of the expandable structure 210. However, because much of the
catheter 201 is located within the lumen of the shaft 348, with the
distal end 206 of the catheter 201 extending into the vertebral
body 105, the shaft 348 will desirably constrain expansion of the
expandable structure 210, causing the expandable structure 210 to
expand primarily at the distal end 206 of the catheter 200.
Desirably, further insertion or withdrawal of the catheter 201 will
alter the amount of the expandable structure 210 extending from the
distal end of the shaft 348, thereby increasing or decreasing the
length of the expandable structure 210 that is free to expand
within the vertebral body 105. By choosing the amount of catheter
201 to insert into the vertebral body 105, the practitioner can
alter the length of the expandable structure, and ultimately the
size of the cavity 170 created by the catheter 201, during the
surgical procedure. Therefore, the disclosed embodiments can
obviate and/or reduce the need for multiple catheters of varying
lengths. If desired, markings 269 (see FIG. 9) can be placed along
the proximal section of the catheter which correspond to the length
of the catheter 201 extending from the shaft 348, allowing the
practitioner to gauge the size of the expandable structure 210 of
the catheter 200 within the vertebral body 105. Similarly, in an
alternate embodiment as disclosed below, the cavity-forming device
201 could incorporate markings corresponding to the length of the
bristles 425 extending beyond the tip of the shaft 348.
[0089] In an alternate embodiment, shown in FIG. 13, the length of
an expandable section 211 of the catheter can be further
constrained by securing and/or adhering the expandable structure
210 at a secondary location 214 along the hollow tube 205, thereby
limiting expansion beyond the secondary location 214. For example,
if a desired maximum length of the expandable section 211 were 3
inches, then the expandable structure 210 could be secured to the
hollow tube 205 at a secondary location 214 approximately three
inches from the distal end 206 of the hollow tube 205. This
arrangement would desirably allow a practitioner to choose an
expanded length of the expandable section 211 of up to three
inches, while limiting and/or preventing expansion of the remaining
section 203 of the catheter 201. This arrangement can also prevent
unwanted expansion of the portion 202 of the catheter extending out
of the proximal end 191 of the shaft body 348 (see FIG. 5C).
[0090] As previously noted, in the disclosed embodiment, the
expandable structure is desirably secured to the distal end of the
hollow tube, which will facilitate recovery of fragments of the
expandable structure 210 if the expandable structure 210 is torn or
damaged, such as by a complete radial tear. Because the hollow tube
205 will desirably remain attached to the fragments (not shown) of
the expandable structure 210, these fragments can be withdrawn from
the vertebral body 105 with the hollow tube 205. In addition, the
distal attachment will desirably prevent and/or reduce significant
expansion of the expandable structure 210 along the longitudinal
axis of the hollow tube 205.
[0091] FIG. 17 depicts a cavity-forming device 300 constructed in
accordance with an alternate embodiment of the present invention.
Because many of the features of this embodiment are similar to
embodiments previously described, like reference numerals will be
used to denote like components. In this embodiment, the hollow tube
205 extends through the fitting 220, such as a t-shaped fitting,
and is secured to a cap 310. In a preferred embodiment, the hollow
tube 205 is capable of rotation relative to the fitting 220. If
desired, a seal (not shown), such as a silicone or teflon o-ring,
can be incorporated into the proximal fitting 222 to limit and/or
prevent leakage of inflation medium past the hollow tube 205.
[0092] In use, a cavity-forming device 300 compresses cancellous
bone and/or forms a cavity in a manner similar to the embodiments
previously described. However, once the cavity is formed and
withdrawal of the device 300 is desired, the cap 310 can be
rotated, twisting the expandable material 210 relative to the
fitting 220 and drawing the expandable structure 210 against the
hollow tube 205, desirably minimizing the overall outside diameter
of the expandable portion of the device 300. The device 300 can
then easily be withdrawn through the shaft 348. Even where the
expandable structure 210 has plastically deformed, or has failed in
some manner, the present embodiment allows the expandable structure
210 to be wrapped around the hollow tube 205 for ease of withdrawal
and/or insertion. Alternatively, the hollow tube 205 may be capable
of movement relative to the longitudinal axis of the fitting 220,
which would further stretch and/or contract the expandable
structure 210 against the hollow tube 205.
[0093] FIGS. 6A and 6B depict a cavity-forming device 410
constructed in accordance with an alternate embodiment of the
present invention. Cavity-forming device 410 comprises a shaft 420
which is desirably sized to pass through the shaft 348 of an
insertion device 350. A handle assembly 415, which facilitates
manipulation of the cavity-forming device 410, is secured to the
proximal end 412 of the shaft 420. One or more wires or "bristles"
425 are secured to the distal end 423 of the shaft 420. The
bristles 425 can be secured to the shaft 420 by welding, soldering,
adhesives or other securing means well known in the art.
Alternatively, the bristle(s) 425 can be formed integrally with the
shaft 420, or can be etched from a shaft using a laser or other
means well known in the art. The bristles and shaft may be formed
of a strong, non-reactive, and medical grade material such as
surgical steel. In one embodiment, the bristles 425 extend along
the longitudinal axis of the shaft 425, but radiate slightly
outward from the shaft axis. In this manner, the bristles 425 can
be collected or "bunched" to pass through the shaft 348, but can
expand or "fan" upon exiting of the shaft 348. If desired, the
bristles can be straight or curved, to facilitate passage through
the cancellous bone 115. In addition, if desired, one or more of
the bristles 425 may be hollow, allowing a practitioner to take a
biopsy sample of the cancellous bone during insertion of the device
410.
[0094] As shown in FIG. 7, the cavity-forming device 410 can
desirably be inserted through a shaft 348 positioned in a targeted
bone, such as a vertebral body 105. As the bristles 425 enter the
cancellous bone 115, the bristles 425 will desirably displace the
bone 115 and create one or more cavities 426 or preferred flowpaths
in the vertebral body. If desired, a practitioner can withdraw the
bristles 425 back into the shaft 348, reposition the cavity-forming
device 410 (such as by rotating the device 410), and reinsert the
bristles 425, thereby creating additional cavities in the
cancellous bone 115. After removal of the cavity-forming device
410, a material, such as a bone filler (not shown), may be
introduced through the shaft 348. The bone filler will desirably
initially travel through the cavities 426 created by the bristles
425. If desired, a practitioner may interrupt introduction of the
bone filler and create additional cavities by reinserting the
cavity-forming device 410. In addition, in the event bone filler
leakage occurs or is imminent, a practitioner can interrupt bone
filler injection, create additional cavity(ies) as described above,
wait for the introduced/leaking bone filler to harden sufficiently
to resist further extravazation, and then continue introduction of
bone filler. As previously described, the bone filler could
comprise many different materials, or combinations of materials,
with varying results.
[0095] FIG. 14 depicts a cavity-forming device 500 constructed in
accordance with an alternate embodiment of the present invention.
The cavity-forming device 500 comprises a shaft 520 which is sized
to pass through the shaft 348 of an insertion device 350. A handle
assembly 515, which facilitates manipulation of the cavity-forming
device 500, is secured to the proximal end 512 of the shaft 520.
The shaft 520 of the cavity-forming device 500 is desirably longer
than the shaft 348 of the insertion device 350. The distal end 525
of the shaft 520 can be beveled (not shown) to facilitate passage
through cancellous bone 115, or can be rounded or flattened to
minimize opportunities for penetrating the anterior wall 10 of the
vertebral body 105. In addition, if desired, the distal 525 end of
the shaft 520 could be hollow (not shown), allowing the
practitioner to take a biopsy sample of the cancellous bone 115
during insertion of the device 500.
[0096] FIG. 15 depicts a cavity-forming device 600 constructed in
accordance with an alternate embodiment of the present invention.
Cavity-forming device 600 comprises a shaft 620 which is sized to
pass through the shaft 348 of an insertion device 350. A handle
assembly 615, which facilitates manipulation of the cavity-forming
device 600, is secured to the proximal end 612 of the shaft 620.
The shaft 620 is desirably longer than the shaft 348 of insertion
device 350. The distal end 625 of the shaft 620 can be beveled (not
shown) to facilitate passage through cancellous bone 115, or can be
rounded or flattened to minimize opportunities for penetrating the
anterior wall 10 of the vertebral body 105. In this embodiment, the
distal end 625 of the device 600 incorporates drill threads 627
which can facilitate advancement of the device 600 through
cancellous bone 115. In addition, if desired, the distal 625 end of
the shaft 620 could be hollow, allowing the practitioner to take a
biopsy sample of the cancellous bone 115 during insertion of the
device 600.
[0097] After removal of the device(s), bone filler (not shown) may
be introduced through the shaft 348. Desirably, the bone filler
will initially travel through the cavity(ies) created by the
device(s). If desired, a practitioner can interrupt introduction of
bone filler and create additional cavity(ies) by reinserting the
device(s). In addition, in the event bone filler leakage occurs or
is imminent, the practitioner can interrupt bone filler
introduction, create additional cavity(ies) as described above,
wait for the introduced/leaking bone filler to harden sufficiently,
and then continue introducing bone filler. As previously described,
the bone filler could comprise many different materials, or
combinations of materials, with varying results.
[0098] FIGS. 18-20 depicts a cavity-forming device 600a constructed
in accordance with another alternate embodiment of the present
invention. Because many of the components of this device are
similar to those previously described, similar reference numerals
will be used to denote similar components. Cavity-forming device
600a comprises a shaft 620a which is sized to pass through the
shaft 348 of an insertion device 350. A handle assembly 615a, which
facilitates manipulation of the cavity-forming device 600a, is
secured to the proximal end 612a of the shaft 620a. The shaft 620a
is desirably longer than the shaft 348 of insertion device 350. The
distal end 625a of the shaft 620a can be rounded or beveled to
facilitate passage through cancellous bone 115, or can be or
flattened to minimize opportunities for penetrating the anterior
wall 10 of the vertebral body 105.
[0099] An opening or window 700 is desirably formed in the shaft
620a. As shown in FIGS. 19 and 20, an expandable structure 710 is
located at least partially within the shaft 620a, desirably at a
position adjacent the window 700. Upon introduction of inflation
fluid through a lumen extending through the shaft 620a, the
expandable structure 710 expands and at least a portion of the
expandable structure 710 will extend out of the shaft 620a through
the window 700. Desirably, as the structure continues to expand,
the expandable structure 710 will "grow" (P1 to P2 to P3 in FIG.
20) through the window 700, thereby compacting cancellous bone,
creating a cavity and/or displacing cortical bone. Upon contraction
of the expandable structure 710, most of the expandable structure
710 will desirably be drawn back into the shaft 620a for removal of
the tool from the vertebral body. In one embodiment, at least a
portion of the material comprising the expandable structure 710
will plastically deform as it expands.
[0100] The expandable structure 710 may be comprised of a flexible
material common in medical device applications, including, but not
limited to, plastics, polyethylene, mylar, rubber, nylon,
polyurethane, metals or composite materials. Desirably, the shaft
620a will comprise a material that is more resistant to expansion
than the material of the expandable structure 710, including, but
not limited to, stainless steel, ceramics, composite material
and/or rigid plastics. In an alternate embodiment, similar
materials for the expandable structure 710 and shaft 620a may be
used, but in different thickness and/or amounts, thereby inducing
the expandable structure to be more prone to expansion than the
shaft 620a material. The expandable structure 710 may be bonded
directly to the shaft 620a by various means well known in the art,
including, but not limited to, means such as welding, melting,
gluing or the like. In alternative embodiments, the expandable
structure may be secured inside or outside of the shaft 620a, or a
combination thereof.
[0101] As previously noted, any of the cavity-forming devices 500,
600 and 600a may be inserted through a shaft 348 positioned in a
targeted bone, such as a vertebral body 105. As the device(s) enter
the cancellous bone 115, they will desirably displace the bone 115
and create one or more cavities in the vertebral body. If desired,
the physician can withdraw the device(s) back into the shaft 348
and reinsert as necessary to create the desired cavity(ies) in the
cancellous bone 115.
[0102] In the embodiment of a cavity-forming device of FIGS. 18-20,
the cavity-forming device 600a may be utilized without an
associated insertion device. In such a case, the cavity-forming
device desirably will incorporate a sharpened distal tip capable of
penetrating the soft tissues and cortical/cancellous bone of the
vertebral body. If desired, the distal tip can be hollow or a solid
construct. Similarly, the window may extend around more or less of
the periphery of the shaft 620a, depending upon the size and
configuration of the expandable structure and the desired strength
of the cavity-forming device.
[0103] By creating one or more cavities within the cancellous bone
115, the cavity-forming devices of the present invention desirably
create preferred flowpaths for the bone filler 180. In addition,
the cavity-forming devices can also desirably close and/or block
other natural flowpaths out of the cavity, such as veins and/or
cracks in the cancellous bone. Moreover, methods and devices
disclosed herein can be used to manipulate bone filler already
introduced into the bone. Thus, the present invention reduces
opportunities for cement leakage outside of the vertebral body
and/or improves the distribution of bone filler throughout
significant portions of the vertebral body. In addition, the
creation of cavities and desired flowpaths described in the present
invention permits the placement of biomaterial more safely, under
greater control and under lower pressures.
[0104] In addition to the specific uses described above, the
cavity-forming devices and methods described herein would also be
well-suited for use in treating and/or reinforcing weakened,
diseased and/or fractured bones and other organs in various
locations throughout the body. For example, the disclosed devices
and methods could be used to deliver reinforcing materials and/or
medications, such as cancer drugs, replacement bone cells,
collagen, bone matrix, demineralized calcium, and other
materials/medications, directly to a fractured, weakened and/or
diseased bone, thereby increasing the efficacy of the materials,
reinforcing the weakened bone and/or speed healing. Moreover,
injection of such materials into one bone within a body could
permit the medication/material to migrate and/or be transported to
other bones and/or organs in the body, thereby improving the
quality of bones and/or other organs not directly injected with the
materials and/or medications.
[0105] Other embodiments and uses of the invention will be apparent
to those skilled in the art from consideration of the specification
and practice of the invention disclosed herein. All documents
referenced herein are specifically and entirely incorporated by
reference. The specification and examples should be considered
exemplary only with the true scope and spirit of the invention
indicated by the following claims. As will be easily understood by
those of ordinary skill in the art, variations and modifications of
each of the disclosed embodiments can be easily made within the
scope of the claims.
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