U.S. patent application number 10/230949 was filed with the patent office on 2003-04-10 for ultrasound device for treatment of intervertebral disc tissue.
Invention is credited to Burdette, Everette C., Deardorff, Dana L..
Application Number | 20030069569 10/230949 |
Document ID | / |
Family ID | 26924710 |
Filed Date | 2003-04-10 |
United States Patent
Application |
20030069569 |
Kind Code |
A1 |
Burdette, Everette C. ; et
al. |
April 10, 2003 |
Ultrasound device for treatment of intervertebral disc tissue
Abstract
An ultrasound device and method for the treatment of
intervertebral disc tissue for remediation of back pain. An
applicator comprises a catheter and/or needle with a distal tip
including one or more ultrasound transducer crystals. The crystals
produce high-powered ultrasound energy that is transmitted and
absorbed in the disc tissue. The resulting temperature elevation of
the disc tissue shrinks the collagen fibers in the surrounding
tissue, and/or destroying small nerves that may have invaded and
innervated the surrounding degenerated tissue, and can provide
increased structural integrity and disc support for the fragmented
nucleus pulposus to relieve pressure on the spinal nerves.
Inventors: |
Burdette, Everette C.;
(Champaign, IL) ; Deardorff, Dana L.; (Oakland,
CA) |
Correspondence
Address: |
Michael D. Rechtin
Foley & Lardner, One IBM Plaza
Suite 3300
330 North Wabash Avenue
Chicago
IL
60611-3608
US
|
Family ID: |
26924710 |
Appl. No.: |
10/230949 |
Filed: |
August 29, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60315841 |
Aug 29, 2001 |
|
|
|
Current U.S.
Class: |
606/27 ;
607/96 |
Current CPC
Class: |
A61N 2007/0078 20130101;
A61B 2017/00261 20130101; A61N 7/02 20130101; A61N 2007/0021
20130101 |
Class at
Publication: |
606/27 ;
607/96 |
International
Class: |
A61B 018/04 |
Claims
1. A minimally invasive applicator device for treatment of
intervertebral disc tissue, comprising: an insertion device having
a proximal end and a distal end for insertion into the
intervertebral disc tissue, the insertion device being structurally
robust for direct insertion into a targeted area of intervertebral
disc tissue without damage or misalignment; an ultrasound
transducer crystal coupled to the distal end of the applicator; and
an external RF power generator electrically connected to the
ultrasound transducer, the generator providing power to the
ultrasound transducer.
2. The applicator device of claim 1, wherein the insertion device
comprises a catheter or needle.
3. The device of claim 2, wherein in the ultrasound transducer
crystal includes at least one individual electrical power
connection and control element.
4. The device of claim 3, wherein a plurality of transducer
crystals are aligned to form an array along the applicator device,
wherein each transducer crystal includes an individual electrical
power connection.
5. The device of claim 3, wherein the ultrasound transducer crystal
has a cylindrical shape to transmit radially dispersive or radially
focused ultrasound energy.
6. The device of claim 3, wherein the ultrasound transducer crystal
is substantially planar.
7. The device of claim 3, wherein the ultrasound transducer crystal
is sectioned electrically and/or mechanically to provide separate
active elements within a single ultrasound transducer crystal.
8. The device of claim 3, further comprising a thermocouple placed
on or adjacent to the ultrasound transducer crystal, the
thermocouple monitoring the surface temperature of the device
and/or the temperature of the tissue/device interface.
9. The device of claim 3, further comprising a thermocouple placed
within the intervertebral disc tissue to monitor the temperature of
the intervertebral disc tissue.
10. The device of claim 9, wherein the thermocouple is deployed
into the intervertebral disc tissue from the applicator.
11. The device of claim 2, further comprising means to cool the
internal transducer heating by circulating a flow of a liquid or
gaseous coolant through the applicator.
12. The device of claim 1, further comprising a guidewire coupled
to the applicator, wherein the applicator is flexible and can be
directed or steered by the guidewire in a specific direction within
the intervertebral disc tissue.
13. The device of claim 1, further comprising a separate insertion
tool or sheath for introduction into the intervertebral disc
tissue, and wherein the applicator is inserted into the tissue
through the lumen of the insertion tool or sheath.
14. The device of claim 13, wherein the insertion tool comprises a
predetermined fixed shape, and wherein the applicator is flexible
to accommodate the fixed shape in its passage into the
intervertebral disc tissue.
15. The device of claim 1, wherein the distal end of the applicator
device is fixedly curved to provide enhanced accessibility of the
ultrasound transducer to the posterior region of the intervertebral
disc.
16. The device of claim 2, wherein the ultrasound transducer
crystal is capable of being used to provide diagnostic ultrasound
imaging of the intervertebral disc tissue and surrounding
tissue.
17. A method for treating intervertebral degenerated disc tissue,
comprising the steps of: inserting, positioning and guiding an
applicator device into intervertebral disc tissue via diagnostic
imaging; applying power to at least one ultrasound transducer, the
at least one ultrasound transducer heating a designated area of the
intervertebral disc tissue; removing the applicator from the
intervertebral disc tissue.
18. The method of claim 17, wherein the applicator is positioned
and guided via intra-operative fluoroscopic imaging.
19. The method of claim 17, wherein the applicator is positioned
and guided using laparoscopic and/or endoscopic techniques.
20. The method of claim 17, wherein the diagnostic imaging
comprises ultrasound imaging provided by the transducer crystals
located within the applicator device.
21. The method of claim 17, further comprising the step of
measuring the temperature on the applicator and/or in the
surrounding tissue.
22. The method of claim 17, further comprising the step of heating
an entrance hole with the applicator device in order to produce
thermal sealing or shrinking of the tissue upon removal of the
applicator.
23. The method of claim 17, wherein the transducer heating is
controlled by varying the power, frequency, or duration of the
applied signal to each of the transducer crystals.
24. The method of claim 17, further comprising the step of
delivering a drug or therapeutic agent into the intervertebral disc
tissue to enhance the therapeutic effect of the thermal energy
delivery.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to ultrasound
applicator devices. More particularly, the present invention
relates to the structure, design and use of a minimally invasive
ultrasound applicator device for the thermal treatment and repair
of intervertebral disc tissue.
BACKGROUND OF THE INVENTION
[0002] The concept of using heat to treat degenerated disc tissue
is conventionally known. For example, the orthopedic company ORATEC
Interventions, Inc. has developed and marketed a device for thermal
spine treatment based on Intra-Discal Electro-Thermal (IDET)
technology. IDET technology involves a minimally invasive catheter
using RF induction of a hot-wire tip for thermal conduction.
[0003] While relatively straightforward in design and use, the
ORATEC device is very limited in thermal capabilities and
ultimately in treatment efficacy. The region of disc tissue that is
heated with this device is quite small with a sharp temperature
fall-off from the surface of the catheter tip (therapeutic
temperature elevation in the tissue is estimated to be only 1-3 mm
from the catheter). As a result, the treatment itself is likely
limited in effectiveness for any given patient, simply because the
volume of tissue that is heated is not large enough to produce a
significant therapeutic effect (i.e., shrinkage of collagen fibers,
destruction of invading nerves, and/or reduction of pressure on the
spinal nerves).
[0004] Furthermore, the design and treatment approach of the IDET
catheter is significantly limiting in the general treatment
population--it is estimated that more than 50% of the potential
treatment population is not even a candidate for this device
therapy. This is due to the use of a flexible "navigable catheter"
which must be circumnavigated around the disc border between the
annulus and the nucleus, positioning the treatment tip back at the
posterior region of the degenerated disc. This positioning is
possible with a healthy or slightly degenerated disc because the
fibers of the annulus help "steer" the catheter around the disc
tissue. However, with greater disc degeneration, this positioning
is not possible because of the tissue degradation; there is no
structure for the catheter to steer around, providing the danger of
slippage and puncturing the opposite wall. As a result, the
majority of patients, especially those with advanced degeneration
or herniation, cannot be treated with this approach.
SUMMARY OF THE INVENTION
[0005] It is therefore an object of the invention to provide a
treatment device which provides a significant improvement both in
the thermal capabilities and therapeutic effects for disc
tissue.
[0006] It is another object of the invention to provide a treatment
device which can be used on an increased percentage of the
potential treatment population and disease states.
[0007] It is yet another object of the invention to provide an
ultrasound device that can effectively heat an increased volume of
tissue for greater therapeutic effect.
[0008] It is still another object of the invention to provide an
ultrasound device and treatment approach that allows for treatment
during more advanced stages of disc degeneration.
[0009] It is finally another object of the invention to provide a
robust design for an ultrasound device during insertion while also
providing for improved directional control.
[0010] Further advantages and features of the present invention
will be apparent from the following specifications and claims
illustrating the preferred embodiments of the present
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a perspective view of the ultrasound device
according to one embodiment of the invention as it is positioned
and maneuvered within the spinal body;
[0012] FIG. 2 is a side view of a plurality of segmented transducer
elements with individual power control according to one embodiment
of the invention;
[0013] FIG. 3 is a side view of an alternate embodiment of the
invention showing a curved array of transducer elements;
[0014] FIG. 4 is a cross-sectional view of a transducer element
according to one embodiment of the invention;
[0015] FIG. 5 is a cross-sectional view of a transducer element
according to another embodiment of the invention; and
[0016] FIG. 6 is a cross-sectional view of an individual transducer
element according to yet another embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0017] The present invention includes an applicator comprising a
catheter and/or a needle with a distal tip for direct insertion
into the tissue of the intervertebral disc. At the distal tip of
the applicator is one or more ultrasound transducer crystals for
producing high-powered ultrasound energy to be transmitted and
absorbed in the disc tissue. In one embodiment of the invention,
energy for the ultrasound transducer(s) is produced by an external
RF power generator and delivered through electrical wires connected
to the applicator. Small thermocouples can be placed on the
ultrasound transducer/applicator and/or in the surrounding tissue
to monitor the temperature. Means are also provided for active
cooling of the ultrasound transducers by circulating flow of liquid
or gas within the applicator.
[0018] The treatment process is initiated with the placement of the
applicator device into the posterior region of the intervertebral
disc tissue. The positioning of the applicator to the selected
region of disc degeneration is guided via on-line diagnostic
imaging, such as intra-operative fluoroscopic imaging. Power to the
ultrasound device is then produced at a level to provide
significant temperature elevation of the surrounding disc tissue.
In one embodiment of the invention, the temperature elevation is
greater than 60.degree. C. for the targeted tissue. The temperature
elevation is intended to shrink the collagen fibers in the
surrounding tissue of the annulus fibrosus, and/or destroy small
nerves that may have invaded and innervated the surrounding
degenerated tissue, and/or provide greater structural integrity and
disc support for the fragmented nucleus pulposus to relieve
pressure on the spinal nerves.
[0019] Although these therapeutic effects are intended primarily
for treatment of disc degeneration and herniation, this treatment
approach with the ultrasound device may also be useful for other
symptomatic spinal problems causing back pain, leg pain, etc.
Additionally, the ultrasound device may be used to thermally shrink
and/or seal the entrance hole and any subsequent unwanted tissue
damage upon removal of the applicator from the disc tissue. In
another embodiment of the device, the ultrasound transducers may
also be used for diagnostic imaging to guide and monitor the
treatment process.
[0020] The improvements described herein result primarily from the
fundamental advantages of ultrasound propagation and heating of
soft tissue. The effective energy delivery into the tissue allows
for thermal treatment of larger tissue volumes in shorter times.
Furthermore, the ultrasound device can be designed to provide
selective control of the energy delivery to target and treat a
specific region of tissue, dynamically controlling both the size
and shape of the thermal treatment region. Extensive research and
development activities have previously been completed on such
ultrasound devices, and prototype applicators prepared for clinical
application have demonstrated the feasibility of this approach.
[0021] FIG. 1 shows the ultrasound device positioned in the spinal
body according to one embodiment of the invention. The ultrasound
device, shown generally at 10, comprises a catheter or needle 12
with a plurality of ultrasound transducer crystals 14 at one end
thereof. A guidewire 16 can be placed within the catheter or needle
12 for controlling the direction of the ultrasound device 10 inside
the spinal body, shown generally at 18.
[0022] FIGS. 2-3 show different embodiments of the individual
transducer crystals 14. FIG. 2 shows a plurality of segmented
transducer crystals 14. Depending upon the particular system and
procedure requirements, it is possible for each of the transducer
crystals 14 to have individual power control. The embodiment shown
in FIG. 3 discloses a curved array of transducer crystals 14. It is
possible for the array of transducer crystals 14 to be permanently
curved. Alternatively, the array could be flexible based upon the
direction and shape of the guidewire 16.
[0023] FIGS. 4-6 show different potential cross-sectional shapes
for the transducer crystals 14. FIG. 4 discloses a transducer
crystal 14 with a cylindrically shaped cross-section. It is
possible for the transducer crystal 14 to include or not include
angular sectoring. FIG. 5 shows the transducer crystal as having a
curvi-linear cross-section. This transducer crystal 14 could have a
focused or defocused cross-section, depending on the direction of
activation of ultrasound energy. The transducer crystal of FIG. 6
has a substantially planar cross-section. Transducer crystals 14
having cross-sections of other shapes are also possible without
departing from the invention's broader aspects.
[0024] Additionally, the ultrasound device 10 could use a cooling
method, either actively or passively, in order to remove thermal
waste energy from the transducer crystal and improve the device's
power and performance.
[0025] While the preferred embodiments of the invention have been
described, it will be understood by those skilled in the art to
which the invention pertains that numerous modifications and
changes may be made without departing from the true spirit and
scope of the invention. It is accordingly intended to define the
scope of the invention precisely in the claims appended to and
forming a part of this application.
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