U.S. patent application number 11/604444 was filed with the patent office on 2007-04-26 for apparatus for axial compression of a patient's spine.
Invention is credited to Daniel S.J. Choy.
Application Number | 20070089237 11/604444 |
Document ID | / |
Family ID | 39468262 |
Filed Date | 2007-04-26 |
United States Patent
Application |
20070089237 |
Kind Code |
A1 |
Choy; Daniel S.J. |
April 26, 2007 |
Apparatus for axial compression of a patient's spine
Abstract
A spinal compression device includes a shoulder harness, a
footplate assembly connected to the shoulder harness by at least
one connecting member, At least one hydraulic actuator is
mechanically coupled to the footplate assembly. The hydraulic
actuator has proximal and distal ends and a piston mechanically
coupled to the connecting member. A hydraulic energy source is in
fluid communication with the hydraulic actuator through hydraulic
lines. The footplate assembly is only connected to the hydraulic
source by the hydraulic lines.
Inventors: |
Choy; Daniel S.J.; (New
York, NY) |
Correspondence
Address: |
STEVEN L. NICHOLS;RADER, FISHMAN & GRAVER PLLC
10653 S. RIVER FRONT PARKWAY
SUITE 150
SOUTH JORDAN
UT
84095
US
|
Family ID: |
39468262 |
Appl. No.: |
11/604444 |
Filed: |
November 27, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11238918 |
Sep 28, 2005 |
|
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11604444 |
Nov 27, 2006 |
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Current U.S.
Class: |
5/600 |
Current CPC
Class: |
A61B 5/4561
20130101 |
Class at
Publication: |
005/600 |
International
Class: |
A47B 71/00 20060101
A47B071/00 |
Claims
1. A spinal compression device, comprising: a shoulder harness; a
footplate assembly connected to said shoulder harness by at least
one connecting member; at least one hydraulic actuator mechanically
coupled to said footplate assembly, said hydraulic actuator having
a proximal end, a distal end, and a piston mechanically coupled to
said connecting member; and a hydraulic energy source in fluid
communication with said hydraulic actuator through hydraulic lines;
wherein said footplate is only connected to said hydraulic source
by said hydraulic lines.
2. The device of claim 1, wherein said hydraulic energy source
comprises a flexible reservoir and a pump.
3. The device of claim 2, wherein said pump comprises an input in
fluid communication with said flexible reservoir and an output in
fluid communication with said distal end of said hydraulic
actuator.
4. The device of claim 3, further comprising a valve intermediate
and in fluid communication with said output of said pump and said
distal end of said hydraulic cylinder.
5. The device of claim 4, wherein hydraulic fluid is permitted to
flow between said pump and said distal end of said hydraulic
chamber when said valve is in a first position and hydraulic fluid
is prevented from flowing between said pump and said distal end of
said hydraulic chamber when said valve is in a second position.
6. The device of claim 2, wherein said flexible reservoir comprises
an input in fluid communication with said proximal end of said
hydraulic actuator and an output in fluid communication with said
pump.
7. The device of claim 1, wherein adding hydraulic fluid to said
distal end of said hydraulic actuator increases axial force on said
shoulder harness in a direction toward said footplate.
8. The device of claim 1, wherein adding hydraulic fluid to said
proximal end of said hydraulic actuator decreases axial force on
said shoulder harness in a direction toward said footplate.
9. The device of claim 1, wherein said connecting member comprises
a non-distensible strap.
10. The device of claim 1, further comprising a gauge coupled to
said footplate assembly for measuring a pressure exerted on said
footplate assembly.
11. The device of claim 10, wherein said gauge outputs an
indication of intra-disc pressure experienced by a patient based on
a correlation of said pressure exerted on said footplate assembly
and said intra-disc pressure.
12. The device of claim 11, wherein said gauge is located at a
remote location away from said footplate assembly.
13. The device of claim 1, wherein said hydraulic source is located
at a remote location away from said footplate assembly.
14. A method of examining a spinal intra-disc region, comprising:
coupling a shoulder harness to a patient; placing the feet of said
patient in contact with a footplate, said footplate being coupled
on one side to said shoulder harness by a coupling member and to at
least one hydraulic piston of a hydraulic actuator on another side;
pumping hydraulic fluid into an end of said hydraulic actuator; and
imaging said intra-disc region; wherein said pumping retracts said
hydraulic piston and exerts an axial force on said shoulder harness
towards said footplate.
15. The method of claim 14, further comprising performing a
preliminary imaging operation on said intra-disc region before
pumping said hydraulic fluid.
16. The method of claim 14, wherein imaging said intra-disc region
includes performing a magnetic resonance imaging operation.
17. The method of claim 14, wherein said axial force produces a
pressure within said intra-disc region of about 150 kPa.
18. The method of claim 14, further comprising monitoring a gauge,
said gauge being configured to display an intra-disc pressure value
based on a correlation between pressure on said footplate assembly
and intra-disc pressure.
19. The method of claim 14, further comprising releasing said
hydraulic fluid from said end of said hydraulic actuator if said
force is maintained for a maximum time threshold.
20. The method of claim 14, further comprising releasing said
hydraulic fluid from said end of said hydraulic actuator if said
force reaches a maximum threshold.
Description
RELATED APPLICATIONS
[0001] The present application is a continuation in part of U.S.
patent application Ser. No. 11/238,918 filed Sep. 28, 2005 in the
name of Daniel S. J. Choy, which application is incorporated herein
by reference in its entirety.
BACKGROUND
[0002] Human spinal or vertebral column consists of a plurality of
separate vertebrae. The vertebrae are joined so as to permit a
range of forward, backward, and sideways movement of the column. At
the lower end of the spinal column are the lumbar vertebrae, which
support the small of the back. Above the lumbar vertebrae are the
thoracic vertebrae, which lie behind the thoracic or chest cavity.
The uppermost, or cervical, vertebrae define the skeletal framework
of the neck. The vertebrae are separated and supported by
cartilaginous discs. These discs are subject to deterioration and
disease, often creating significant pain. In some cases, the discs
rupture or "herniate."
[0003] Studies have shown that the intra-disc pressure in the
lumbar spine while in a supine position is about 15 kilo-Pascals
(kPa), while pressures in the sitting position average about 150
kPa. Consequently, the observation that patients with herniated
lumbar disc disease are often least comfortable in the sitting
position may be at least partially due to such pressure
differences.
[0004] Magnetic Resonance Imaging (MRI) techniques are often used
in the diagnosis of lumbar disc disease. Experience has shown,
however, that there is often a significant discrepancy between the
severity of the patient's clinical symptoms and evidence of disease
shown through magnetic resonance imaging. This discrepancy can be
explained, in part, by the general inability of conventional MRI
systems to allow the patient's spine to be imaged when placed in a
variety of positions, including the sitting position, so as to vary
the intra-disc pressures and the alignment of the vertebrae.
[0005] As indicated above, the supine position produces low
intra-disc pressure, e.g., 15 kPa. Almost all magnetic resonance
imaging of the lumbosacral spine is performed with the patient in
the supine position with consequently low intra-disc pressure.
Therefore, disc herniation is less likely to be apparent in the MRI
because the patient is in the supine position and experiencing low
intra-disc pressure. Consequently, magnetic resonance images taken
when the patient is in the supine position can be less than optimal
for making an accurate disc herniation diagnosis.
[0006] Accordingly, it is extremely useful to produce higher
intra-disc pressures in the lumbar region during an MRI procedure.
For example, the intra-disc pressure would preferably be on the
order of 150 kPa so as to be comparable to the pressure experienced
when sitting. To this end, recent efforts have been directed toward
creating MRI systems in which the patient sits upright in the
machine. However, these MRI systems are rare and expensive. Other
efforts have been directed at providing for increased intra-disc
pressure in the spine while the patient remains in the supine
position required by conventional MRI units. An example of one such
device is disclosed in U.S. Pat. No. 6,000,399 issued to Choy,
which is incorporated herein by reference in its entirety. This
example will be described below.
[0007] Referring to FIGS. 1A-1C, a device (10) for creating
increased intra-disc pressures while the patient is in a supine
position includes a base or frame (12), which may be of rectangular
shape as shown in the Figures. This base or frame may be a solid
structural member, as shown, or may have an open latticework, a
rail-type construction, or the like. The frame is designed to
comfortably support a supine patient and is constructed of a
material that will not cause false or interfering images during the
MRI. For example, wood, plastic or aluminum structures may be used
as the frame (12). The frame is dimensioned to fit within the
imaging area of an MRI system.
[0008] Shoulder braces (14) are mounted at one end of the frame
(12) and spaced apart so that the patient can place his or her head
between them while his or her shoulders abut the shoulder braces
(14), as shown in FIG. 1C. Each of the shoulder braces (14) may
include an upright post (16) to which a cushion (18) is attached.
The cushions (18) are oriented such that a patient (36) lying on
the frame, as shown in FIG. 1C, can press his or her shoulders
against the cushions (18) by apply force with the legs to a foot
sled (20) that is secured at the other end of the frame (12).
[0009] The location of the foot sled (20) is adjustable so that the
sled (20) can be positioned at any number of locations along the
frame (12) to best accommodate the height of the patient (36). As
best seen in FIG. 1B, the foot sled (20) includes a
vertically-extending footboard (22) that is mounted to a horizontal
base (24) and braced by diagonal struts (26). The sled may be
selectively positioned on the frame (12) by aligning pairs of bores
(28) on the sled (20) with corresponding bores (32) in the frame.
Pins (34) are then inserted into the aligned bores (28, 32) to
secure the position of the foot sled (20) along the length of the
frame (12). The shoulder braces (14), the foot sled (20), and the
pins (34) are of sufficiently rigid construction to withstand the
forces exerted by a patient (36).
[0010] As depicted in FIG. 1C, the patient (36) lies supine on the
frame (12), his or her shoulders abutting the shoulder braces (14)
and his or her feet being placed against the footboard (22) with
the knees slightly bent. Typically, the distance between the
footboard (22) and shoulder braces (14) should be about three
inches less than that of the patient's normal shoulder height.
[0011] Once so positioned, the patient (36) exerts pressure with
his or her legs, by straightening his or her knees, pushing against
the footboard (22) and creates pressure on the shoulders which
press against the shoulder braces (14). This action also applies a
compressive force in the spinal column that can approximate the
pressure experienced in a sitting position.
[0012] The apparatus (10) and patient (36) are placed in the MRI
unit. With the patient (36) exerting pressure with his or her legs
to create the desired intra-disc pressure, imaging of the
compressed spinal area can be performed. The patient (36) is
instructed to maintain the pressure being created by the patient's
legs while the MRI scan is performed. The patient can be asked to
exert more or less pressure as needed.
[0013] A force measuring device, such as a pressure transducer
(38), may be mounted to the footboard (22) and connected to a
remote display apparatus to provide a quantitative measure of the
force being applied by the patient (36). This will also allow the
force to be monitored during the duration of a scan to insure
relative consistency and to allow suitable instructions to be
provided to the patient (36). After the scan is completed, the
patient (36) can relax.
[0014] This approach creates the desired intra-disc pressure in the
spine needed to generate images that are better suited for disc
disease diagnosis. However, this approach relies on the patient
being physically able to produce, and maintain with relative
consistency, intra-disc pressures that are similar to those
experienced in a sitting position. This approach also relies on
being able to insert the device within the MRI system and
relatively position the foot sled and shoulder supports to enable
the patient to apply that desired pressure.
[0015] Attempts have been made to automate the apparatus in FIGS.
1A to 1C but it was believed that it is necessary that the
footplate be securely connected to the flat bed on which the
patient was lying. See U.S. Pat. No. 5,779,733. This resulted in a
cumbersome apparatus that was difficult to position on an MRI
machine.
SUMMARY
[0016] A spinal compression device includes a shoulder harness, a
footplate assembly connected to the shoulder harness by at least
two connecting members. At least two hydraulic actuators are
mechanically coupled to the footplate assembly. The hydraulic
actuator has proximal and distal ends and a piston mechanically
coupled to the connecting member. A hydraulic energy source is in
fluid communication with the hydraulic actuator through hydraulic
lines. The footplate assembly is only connected to the hydraulic
source by the hydraulic lines.
[0017] A method of examining a spinal intra-disc region includes
coupling a shoulder harness to a patient; placing the feet of the
patient in contact with a footplate, the footplate being coupled on
one side to the shoulder harness by a coupling member and to at
least one hydraulic piston of a hydraulic actuator on another side;
pumping hydraulic fluid into an end of the hydraulic actuator, and
imaging the intra-disc region.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The accompanying drawings illustrate various embodiments of
the present apparatus and method and are a part of the
specification. The illustrated embodiments are merely examples of
the present apparatus and method and do not limit the scope of the
disclosure.
[0019] FIGS. 1A-1C illustrate a prior art apparatus.
[0020] FIG. 2 illustrates a device for applying and controlling
intra-disc pressures in a patient's spine according to one
exemplary embodiment.
[0021] FIG. 3 illustrates a patient using the device of FIG. 2.
[0022] FIG. 4 illustrates a footplate assembly according to one
exemplary embodiment.
[0023] FIG. 5 is a graph showing the correlation between footplate
pressure in pounds-per-square-inch (PSI) and intra-disc pressure in
kilo-Pascals (kPa).
[0024] FIG. 6 illustrates the device and patient being placed
within an MRI system.
[0025] FIG. 7 illustrates a method of using the device to establish
pressure in the lumbar discs according to one exemplary
embodiment.
[0026] Throughout the drawings, identical reference numbers
designate similar, but not necessarily identical, elements.
DETAILED DESCRIPTION
[0027] Systems and methods are described herein for selectively
establishing pressure in the spine of a patient, particularly in
the lumbar disc region, while the patient is in a supine position.
The systems and methods disclosed make use of a footplate assembly
and shoulder harness that are not attached to a frame or stationary
surface. Such a configuration may provide for a relatively simple
imaging operation and a relatively simple device for establishing a
pressure while the patient is placed within an imaging system.
Further, the systems and methods are provided herein for directly
reading the intra-disc pressure established in the lumbar disc
region of the patient. Such readings are provided in
kilo-Pascals.
[0028] In the following description, for purposes of explanation,
numerous specific details are set forth in order to provide a
thorough understanding of the present method and apparatus. It will
be apparent, however, to one skilled in the art that the present
method and apparatus may be practiced without these specific
details. Reference in the specification to "one embodiment" or "an
embodiment" means that a particular feature, structure, or
characteristic described in connection with the embodiment is
included in at least one embodiment. The appearance of the phrase
"in one embodiment" in various places in the specification are not
necessarily all referring to the same embodiment.
[0029] FIG. 2 illustrates an example of a device (200) for creating
intra-disc pressure within the human spine. The device (200)
generally includes a footplate assembly (210) coupled to a shoulder
harness (220) by a number of connecting members (230). In this
embodiment the connecting members (230) are straps. The device
(200) is configured to exert controllably increased pressure in,
for example, the lumbar discs of a patient, when the patient is in
a supine position. This increase in pressure is of a similar
magnitude to the pressure that would be experienced if the patient
were in a sitting position.
[0030] The footplate assembly (210) generally includes a footboard
(240) and a hydraulic assembly (250). The footboard (240) is not
attached to any frame or support surface, such as the surface of an
MRI system. The hydraulic assembly (250) controls the forced
exerted by the connecting members (230) between the shoulder
harness (220) and the footboard (240), and the consequent pressure
applied to a patient. The device (200) will also provide a pressure
reading of the intra-disc pressure being created.
[0031] FIG. 3 shows the device (200) in use by a patient. As seen
in FIG. 3, the shoulder harness (220) is worn on the shoulders of
the patient. The shoulder harness (220) is adjustable so that it
can be fitted to the patient. The shoulder harness (220) may be
secured to the patient in a variety of ways, for example, hook and
loop straps, buckles, ties, buttons, clasps and the like.
[0032] As will be described in detail below, the device (200)
provides compressive forces, which are transmitted through the
patient's skeletal structure to the spine, particularly the lumbar
spine area. The patient may be positioned within an MRI system
before the device (200) is worn or activated to obtain an image of
the lumbar disc region in an uncompressed state.
[0033] For example, the shoulder harness (220) may be placed on the
patient while the patient is outside of the MRI system. Thereafter,
the patient is placed within the MRI system while wearing the
shoulder harness (220). At that point, an image of the lumbar disc
region in an uncompressed state is taken.
[0034] Thereafter, the footboard (240), which is portable, is
placed in contact with the feet of the patient. The connecting
members (230) are then connected between the harness (220) and the
footplate assembly (210). The connecting members (230) are adjusted
so as to be taut between the harness (220) and footplate assembly
(210). The hydraulic unit (250) is then used to apply pressure on
the connecting members (230), pulling the harness (220) toward the
footboard (240). If the patient does not bend his or her knees in
response to this pressure, the pressure will be transmitted through
the patient's skeletal structure and create an elevated intra-disc
pressure in the spine.
[0035] After imaging is complete, the hydraulic unit (250) is also
configured to release the pressure on the connecting members (230),
thereby decreasing the pressure applied by the device (200) to the
patient. The hydraulic unit (250) may release the pressure
automatically if the pressure exceeds a maximum threshold.
[0036] One exemplary footplate assembly and hydraulic unit will now
be discussed in detail. FIG. 4 illustrates a footplate assembly
(210) according to one exemplary embodiment. The footplate assembly
(210) generally includes a hydraulic assembly (250) and a footboard
(240).
[0037] The footboard (240) is coupled to a platform base (447) so
that the footboard (240) can be maintained with stability in an
upright position. The platform base (447) is configured to rest on
a stationary surface while allowing the footboard (240) to remain
oriented substantially normal to that surface on which the platform
base (447) rests. Such a configuration allows the footboard (240)
to be moved as desired, rather than being secured to a stationary
surface or frame.
[0038] Although the footplate assembly (210) is mechanically
connected to one or more members of the hydraulic assembly (250)
through hydraulic lines (420, 445), movement of the footplate
assembly (210) within the limits afforded by said hydraulic lines
(420, 445) does not necessarily require corresponding movement of
any member of the hydraulic assembly (250). This feature may prove
particularly useful when adjusting the footplate assembly (210) to
accommodate varying body shapes and sizes of patients.
[0039] The separation and distinction of the footplate assembly
(210) from the hydraulic assembly (250) may also afford versatility
in the placement of the hydraulic assembly (250) according to the
needs and preferences of those who are operating the device (200,
FIG. 2) and the space requirements of the specific area housing the
device (200). Additionally, the hydraulic assembly (250) may be
located at a remote location away from the footplate assembly
(210), such as in a separate room in some embodiments.
[0040] The hydraulic assembly (250) includes, according to one
exemplary embodiment, a base (407) that supports a flexible
reservoir (410) and hydraulic energy source such as a pump unit
(415). The pump unit (415) may be a hand or foot pump. In the
illustrated example, the pump (415) is a foot pump including a
pedal (455) for driving a plunger in a cylinder (450). A hydraulic
line (420) is coupled between the pump (415) and a valve (425). The
valve (425) controls the direction of flow from the pump unit (415)
to the rest of the hydraulic assembly (250). In particular, when
the valve (425) is in a first position, liquid is allowed to flow
from the pump unit (415), through the valve (425), and to first and
second interconnects (430). In this first position, the valve (425)
also prevents liquid from flowing back to the pump unit (415).
[0041] The interconnects (430) are coupled respectively to two
hydraulic actuators (435). Pistons (440) in the actuators (435) are
attached to the connecting members (230) that run to the shoulder
harness. The interconnects (430) provide fluid from the pump unit
(415) into the distal ends (448) of the hydraulic actuators (435).
Fluid flowing from the pump unit (415) and into the distal ends
(448) of the actuators (435) compresses the pistons (440) in the
cylinders thereby exerting a pull or pressure on the connecting
members (230) connected to the pistons (440). This pressure is
transmitted by the connecting members (230) to the shoulder harness
and the patient.
[0042] Return lines (445) allow fluid in the other or proximal ends
(442) of the actuators (435) to flow into the flexible reservoir
(410). This occurs as the pistons in the actuators (435) are
compressed and force fluid into the return lines (445) from the
proximal ends (442) of the actuators (435).
[0043] The hydraulic line (420) and return lines (445) may be
flexible, such that the footboard (240) may be moved relative to
the pump unit (415), the flexible reservoir (410), and the support
plate (407). This facilitates placing the patient in the MRI system
and connecting the footboard (240), via the connecting members
(230), to the shoulder harness on the patient.
[0044] The pump unit (415) and the flexible reservoir (410) may be
located below the surface supporting the footboard (240). This is
advantageous where, as here, the pump unit (415) is a foot
pump.
[0045] The pump unit (415) and the flexible reservoir (410) are
movably independent of the
[0046] As described above, the pump unit (415) includes a cylinder
(450) with a plunger and foot pedal (455). The pump unit (415) may
include a biasing member to drive the plunger and pedal (455)
upward. As the plunger and pedal (455) are urged or drawn upward,
the pump unit (415) draws liquid from the reservoir (410). The foot
pedal (455) provides a platform for the operator to exert pressure
on the pump (415). As the pedal (455) is depressed, liquid is
forced from the pump unit (415) and into the hydraulic line (420).
The liquid flows through the hydraulic line (420) until it comes to
the valve (425). If the valve (425) is in the first position
described above, the liquid flows through the valve (425) and
interconnects (430) into the distal ends (448) of the hydraulic
actuators (435). Consequently, the pistons (440) are compressed and
pressure is applied to the connecting members (230).
[0047] The pump unit (415) may be operated through a series of
strokes to obtain the desired pressure on the patient's spine. Once
the desired pressure is achieved, the valve (425) is closed to
maintain the desired hydraulic pressure within the system. The
hydraulic unit is adjusted to establish a target intra-disc
pressure of approximately 150 kPa. 10-15 kPa more or less than 150
kPa will still enable the system to obtain useful imaging of the
lumbar disc region under pressure.
[0048] To determine when the desired intra-disc pressure has been
achieved, a pressure gauge (457) is coupled to the footboard (240).
It has been discovered that a measure of the pressure of a
patient's feet on the footboard (240), as measured, for example, in
pounds-per-square-inch (PSI) is directly correlated to intra-disc
pressure, measured in kPa. This correlation is illustrated in FIG.
5 and has been established by actually measuring and comparing the
pressure at the footboard with intra-disc pressure in a number of
patients over a range of applied pressures. Interestingly, the
correlation illustrated in FIG. 5 holds true regardless of the
patient's size, weight or body shape.
[0049] Using the correlation in FIG. 5, the pressure gauge (457)
can be calibrated to measure the pressure at the footboard (240)
and output a direct reading of intra-disc pressure in the spine in
kilo-Pascals. This is extremely helpful for establishing the
desired intra-disc pressure needed for accurate imaging and the
diagnosis of lumbar disc disease.
[0050] As a safety feature, the pressure gauge (457) is configured
to release the pressure in the hydraulic assembly (250) when the
intra-disc pressure reaches a maximum level, such as 200 kPa. For
example, the gauge (457) may close the valve (425) or other liquid
pathway to prevent further pressure from being built up. The gauge
(457) may also adjust the valve (425) to allow fluid to flow out of
the distal ends (448) of the actuators (435) and back into the
hydraulic line (420) to ease pressure on the connecting members
(230). The gauge (457) may also divert further fluid to other parts
of the hydraulic assembly (250) to reduce the pressure on the
patient.
[0051] After imaging, the pressure applied to the patient by the
system is released. The hydraulic assembly (250) is configured to
release the pressure driving the ends of the connecting members
(230) toward the footboard (240). According to the present
exemplary embodiment, the valve (425) is configured to be
selectively turned to a second position. While in the second
position, the valve (425) allows liquid to flow from the
interconnects (430) back through the hydraulic line (420).
Compression of the flexible reservoir (420) drives fluid back
through the return lines (445) and into the proximal ends (442) of
the actuators (435). This drives the pistons (440) away from the
footboard (240) and releases the pressure in the connecting members
(230). The movement of the pistons (440) drives fluid from the
distal ends (448) of the actuators (435), through the interconnects
(430) and back into the hydraulic line (420).
[0052] As shown in FIG. 6, the configuration of the device (200)
allows the patient to be placed within an MRI system (600) while
the footplate assembly (210) remains outside. As a result, the
footplate assembly (210) allows for control of pressure in the
lumbar discs of the patient while the patient is within the MRI
system (600).
[0053] The gauge (457; FIG. 4) of the footplate assembly (210)
senses the amount of pressure applied to the footboard (240). This
pressure determination can also be output to and displayed on a
remote gauge (620) that is part of a control console (610). This
allows an MRI system operator who is located at the console (610)
to monitor the pressure applied by the device (200) to ensure that
the pressure is adequate, consistent and within the desire range.
As indicated above the pressure reading on the remote gauge (620)
represents the intra-disc pressure the patient is experiencing in
kilo-Pascals. The remote gauge (620) can also send a signal to a
computer or other processing device of the control console (610)
indicating the pressure applied. This computer or other processing
device may be recording the pressure levels during imaging,
operating a safety system that releases the pressure applied by the
system if that pressure exceeds a maximum threshold, etc.
[0054] Further, the remote gauge (620) may include an indicator
(630) that corresponds to a desired or target lumbar disc pressure.
The desired or target lumbar disc pressure is 150 kPa. The
indicator (630) may also show a maximum pressure, such as 200 kPa,
that should not be exceeded.
[0055] FIG. 7 illustrates a method of operating the devices
described herein to obtain an image of a patient's spine under a
desired pressure. As shown in FIG. 7, the method begins by placing
the shoulder harness on the patient (step 700). As indicated above,
the harness can be adjusted to comfortably fit the patient. The
harness has a structure such that when force is applied to the
straps, the harness will evenly distribute the pressure across the
patient's shoulders and, through the patient's skeletal structure,
to the patient's spine, particularly the lumbar region.
[0056] Next, the patient, wearing the shoulder harness, is placed
in the MRI system (step 705). The footplate assembly is then put in
place with the patient's feet against the footboard (step 710). The
footplate assembly is then connected by the straps or other means
to the shoulder harness (step 715). The straps are adjusted to be
taut (step 720). The straps or connecting members are intermediate
and mechanically coupled to the shoulder harness and a piston of a
hydraulic actuator.
[0057] Then, hydraulic fluid is pumped (step 730) into an end of
the hydraulic actuator, as described above, to apply pressure to
the patient through the straps and shoulder harness. The pumping
(step 730) retracts a hydraulic piston and exerts an axial force on
the shoulder harness towards the footplate Using the gauge
described above, the pressure applied is monitored until the
desired pressure is achieved (determination 740) e.g., an
intra-disc pressure of approximately 150 kPa.
[0058] When the desired pressure has been achieved, the magnetic
resonance imaging is performed to obtain the desired images of the
patient's spine under the applied pressure (step 750). When imaging
is completed, the pressure is released (step 760) and the patient
is removed from the MRI system (step 770). The footplate assembly
and shoulder harness are removed (step 780).
[0059] The preceding description has been presented only to
illustrate and describe the present method and apparatus. It is not
intended to be exhaustive or to limit the disclosure to any precise
form disclosed. Many modifications and variations are possible in
light of the above teaching. It is intended that the scope of the
specification be defined by the following claims.
* * * * *