U.S. patent application number 12/898871 was filed with the patent office on 2011-04-21 for system for determining and placing spinal implants or prostheses.
Invention is credited to Seth L. Neubardt.
Application Number | 20110092859 12/898871 |
Document ID | / |
Family ID | 43879845 |
Filed Date | 2011-04-21 |
United States Patent
Application |
20110092859 |
Kind Code |
A1 |
Neubardt; Seth L. |
April 21, 2011 |
SYSTEM FOR DETERMINING AND PLACING SPINAL IMPLANTS OR
PROSTHESES
Abstract
A system for determining and placing spinal implants or
prostheses includes apparatus for measuring a change in position of
vertebrae at an affected level of a patient's spine from a position
of pain where the patient reports greatest pain originating from
the affected level, to a position of comfort where the patient
reports the least pain from the affected level. Spinal implants or
prostheses are constructed and arranged for urging the affected
level of the spine to the position of comfort when applied to or
placed at determined locations in the affected level. In one
embodiment, an implant device includes one or more inflatable
balloons, wherein each balloon is placed at a certain location in a
disc space at the affected level, and vertebrae above and below the
balloon are urged to the position of comfort at the affected level
when the balloons are inflated.
Inventors: |
Neubardt; Seth L.;
(Mamaroneck, NY) |
Family ID: |
43879845 |
Appl. No.: |
12/898871 |
Filed: |
October 6, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12215097 |
Jun 25, 2008 |
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12898871 |
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60937055 |
Jun 25, 2007 |
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Current U.S.
Class: |
600/594 ;
606/86A; 623/17.11 |
Current CPC
Class: |
A61B 5/4514 20130101;
A61B 90/06 20160201; A61B 17/8855 20130101; A61F 2210/0085
20130101; A61F 2/44 20130101; A61B 2034/105 20160201; A61F 2/441
20130101; A61B 34/10 20160201; A61B 2034/104 20160201; A61B 5/4504
20130101; A61F 2250/0098 20130101; A61B 5/1077 20130101; A61F
2002/3008 20130101; A61F 2002/30583 20130101; A61F 2002/30586
20130101; A61B 5/055 20130101; A61F 2002/30841 20130101; A61B 6/505
20130101; A61B 2090/374 20160201; A61B 5/4561 20130101; A61B
2017/0256 20130101; A61F 2/4657 20130101; A61B 2034/108 20160201;
A61B 90/02 20160201; A61F 2/442 20130101; A61F 2002/302 20130101;
A61F 2230/0065 20130101; A61B 2090/376 20160201; A61B 2034/102
20160201; A61F 2002/30952 20130101 |
Class at
Publication: |
600/594 ;
623/17.11; 606/86.A |
International
Class: |
A61B 5/103 20060101
A61B005/103; A61F 2/44 20060101 A61F002/44; A61B 17/56 20060101
A61B017/56 |
Claims
1. A system for determining and placing spinal implants or
prostheses, comprising: means for measuring a spatial change in
position of vertebrae at an affected level of a patient's spine
from a position of pain (POP) where the patient reports
experiencing a greatest pain determined to originate from the
affected level, to a position of comfort (POC) where the patient
reports experiencing a least pain originating from the affected
level; and one or more spinal implants or prostheses constructed
and arranged for urging the affected level of the patient's spine
to the position of comfort when applied to or placed at determined
locations in the affected level.
2. A system according to claim 1, including a database associated
with the measuring means, wherein the database is configured to
store information concerning a number of spinal implants or
prostheses, and the measuring means is constructed and arranged to
select one or more implants or prostheses from the database
according to the change in position of the vertebrae from the POP
to the POC as measured at the affected level.
3. A system according to claim 2, wherein the implants or
prostheses are selected from among artificial discs, rod/screw
constructs, flexible rods, and distraction devices.
4. A system according to claim 1, wherein the measuring means
comprises a scanner for producing radiographic image data.
5. A system according to claim 1, wherein the measuring means
comprises apparatus for producing an X-ray at the POP and at the
POC.
6. A system according to claim 1, wherein the measuring means
comprises a surgical table.
7. A system according to claim 1, wherein the measuring means
comprises at least one of an electrogoniomter and a
torsiometer.
8. A system for determining and placing spinal implants or
prostheses, comprising: means for measuring a spatial change in
position of vertebrae at an affected level of a patient's spine
from a position of pain (POP) where the patient reports
experiencing a greatest pain determined to originate from the
affected level, to a position of comfort (POC) where the patient
reports experiencing a least pain originating from the affected
level; and an implant device including one or more inflatable
balloons dimensioned and arranged for insertion into a disc space
in the affected level, wherein each balloon of the device is placed
at a determined location in the disc space, and vertebrae above and
below the balloon are urged to the position of comfort at the
affected level when the balloons of the device are inflated.
9. A system according to claim 8, wherein the measuring means
comprises a scanner for producing radiographic image data.
10. A system according to claim 8, wherein the measuring means
comprises apparatus for producing an X-ray at the POP and at the
POC.
11. A system according to claim 8, wherein the measuring means
comprises a surgical table.
12. A system according to claim 8, wherein the measuring means
comprises at least one of an electrogoniomter and a
torsiometer.
13. A system according to claim 8, wherein the implant device
comprises a flexible, generally disk shaped plate, and a plurality
of the inflatable balloons disposed on an inside surface of the
plate.
14. A system according to claim 13, wherein the implant device
includes an inflatable anchor balloon disposed on the inside
surface of the plate, and a spike projecting from an outside
surface of the plate opposite the inside surface in the region of
the anchor balloon, so that the spike is forced into a confronting
vertebral bone when the plate is operatively inserted in the disc
space and the anchor balloon is inflated.
15. A system according to claim 14, wherein the anchor balloon is
shaped so that when inflated, the anchor balloon defines an open
central region inside the disc space.
16. A system according to claim 13, including a tool for inserting
the balloons into the disc space percutaneously, and for inflating
the balloons.
17. A system according to claim 16, wherein the tool comprises a
syringe or pump for dispensing a liquid substance or a cement for
inflating the balloons, a selector device in communication with the
syringe or pump, and a number of balloon filling tubes each of
which has an associated one of the balloons fixed at a distal end
of the tube, wherein the selector device is constructed and
arranged to direct a filling liquid or cement from the syringe or
pump through a selected one of the filling tubes to inflate the
associated balloon.
18. A system according to claim 16, wherein the tool is constructed
and arranged for inserting a bone fixing material into an open
central region inside the disc space after the balloons are
inflated and the vertebrae above and below the balloons are urged
to the position of comfort at the affected level.
19. A system according to claim 18, wherein the anchor balloon is
formed so that when inflated, the anchor balloon defines the open
central region inside the disc space.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part (CIP) of my
co-pending U.S. patent application Ser. No. 12/215,097 filed Jun.
25, 2008, and titled "System for Determining Spinal Implants". The
'097 application claims priority under 35 U.S.C. .sctn.119(e) of
U.S. Provisional Patent Application No. 60/937,055 filed Jun. 25,
2007, and titled "System for Treatment of Spinal Abnormalities
Using Patient Selected Positions".
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention concerns implant or prosthesis devices
and systems for the treatment of spinal abnormalities.
[0004] 2. Discussion of the Known Art
[0005] Surgeons and clinical practitioners use radiographic tools
such as MRI scans and X-rays, together with their experience and
intuition, to evaluate if a patient's spine is configured within a
so-called "normal" range. If not, the surgeon then decides how much
restoration or positional variance must be imparted to the spine in
order to eliminate or reduce back pain using procedures such as,
e.g., spinal fusion or disc replacement. Because any given
surgeon's intuition is usually based on his or her training and the
fellowship program they completed, the current practice of
evaluating patients' spines and identifying implant devices to
treat suspected abnormalities is fraught with uncertainties and
results in patient outcomes that vary widely.
[0006] Further, practitioners today are concerned with not just a
"normal" range of spinal configurations, but also with those static
positions that cause the patient to experience pain. For example, a
patient may have a normal range of motion but still feel pain. And,
pain alone can not be detected by way of an x-ray or scan.
[0007] U.S. Pat. No. 6,708,693 (Mar. 23, 2004) discloses a method
and a device for positioning a patient during MRI imaging
diagnosis. The patient lies supine on a platform with their legs
extended and feet in contact with a footrest, and a harness is worn
above the area of the spine to be compressed and imaged. A pair of
straps fixed to the harness pull the harness toward the footrest,
thereby compressing and flexing the patient's spine as desired for
imaging. U.S. Pat. No. 6,860,272 (Mar. 1, 2005) and U.S. Pat.
Appl'n Pub. No. 2005/0165293 (Jul. 28, 2005) relate to a device
having an adjustable footplate for immobilizing a patient and
compressing the patient's skeleton, joints, and/or spine during
imaging.
[0008] U.S. Pat. Appl'n Pub. No. 2005/0177239 (Aug. 11, 2005)
discloses a method and apparatus for computerized spinal surgery
with an implant device having an inflatable cavity for placement
between end plates of adjacent vertebra. The publication also
discloses (at pars. [0147-48] and [0995-98], and FIGS. 42 & 43)
a surgical procedure wherein the patient is mounted on a support
table, a region of the patient's spine is imaged, a 3-D image file
of the region is obtained and stored, and the file is used for
planning and carrying out computer-controlled implant surgery.
[0009] As far as is known, however, no system or procedure has been
proposed wherein a level of a patient's spine is scanned while the
patient assumes a position where he or she feels a greatest amount
of discomfort, and the same level is scanned again while the
patient assumes a position that yields a greatest amount of
comfort, and a device is identified to be implanted at the scanned
level to maintain the patient's comfort in accordance with the scan
results.
SUMMARY OF THE INVENTION
[0010] According to invention, a system for determining and placing
spinal implants or prostheses includes means for measuring a
spatial change in position of vertebrae at an affected level of a
patient's spine from a position of pain (POP) where the patient
reports experiencing a greatest pain determined to originate from
the affected level, to a position of comfort (POC) where the
patient reports experiencing a least pain originating from the
affected level. One or more spinal implants or prostheses are
constructed and arranged for urging the affected level of the
patient's spine to the position of comfort when applied to or
placed at determined locations in the affected level.
[0011] According to another aspect of the invention, a system for
determining and placing spinal implants or prostheses includes
means for measuring a spatial change in position of vertebrae at an
affected level of a patient's spine from a position of pain (POP)
where the patient reports experiencing a greatest pain determined
to originate from the affected level, to a position of comfort
(POC) where the patient reports experiencing a least pain
originating from the affected level, and an implant device
including one or more inflatable balloons dimensioned and arranged
for insertion into a disc space in the affected level. Each balloon
of the device is placed at a determined position in the disc space,
and vertebrae above and below the balloon are urged to the position
of comfort at the affected level when the balloons are
inflated.
[0012] For a better understanding of the invention, reference is
made to the following description taken in conjunction with the
accompanying drawing and the appended claims.
BRIEF DESCRIPTION OF THE DRAWING
[0013] In the drawing:
[0014] FIGS. 1(a) and 1(b) are frontal and lateral views of a
patient's spine in a normal position;
[0015] FIG. 2 is a view of the spine with full flexion applied;
[0016] FIG. 3 is an AP/frontal view of the spine, showing forces
required to achieve a position of comfort (POC) for the patient
according to the invention;
[0017] FIG. 4 is a lateral view of the spine, showing forces
required to achieve the POC for the patient according to the
invention;
[0018] FIG. 5 is a view of the spine, illustrating a net change in
position to achieve the POC according to the invention;
[0019] FIGS. 6 to 11 chart various steps to be taken when using a
system for determining spinal implants according to the
invention;
[0020] FIG. 12 is a schematic block diagram of a system for
determining spinal implants according to the invention;
[0021] FIGS. 13 to 25 illustrate two hypothetical case studies in
which the inventive system may be applied;
[0022] FIGS. 26 to 35 are views of a first inflatable prosthesis
device according to the invention; and
[0023] FIGS. 36 to 39 are views of a second inflatable prosthesis
device according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0024] The present invention resides in a system for identifying an
optimal spinal implant or prosthesis device for a given patient.
Once a physician identifies a level of the patient's spine that is
acting as a source of discomfort, an appropriate implant or
prosthesis device is determined based on images of the relative
configuration or positions of the vertebrae at the affected level
taken at (i) a position of discomfort or pain (POP) whereat the
patient reports experiencing the greatest amount of back pain, and
(ii) a position of comfort (POC) at which the patient feels most
comfortable. The relative positions of adjacent vertebrae at the
affected level for the POP and the POC may be scanned using known
tools, for example, fluoroscopy, x-ray, or CT scans, which tools
are capable of yielding quantitative measurements of spinal
distraction (elongation), compression (loading), flexion (bending
forward), extension (bending backward), lateral bending,
translation and rotation.
[0025] Images obtained at the POP and the POC for a group of
patients have revealed that the POC for a given patient is usually
a polar opposite from POP, and vice versa. For example, patients
who are most comfortable with traction on their back, for example,
by sitting in a chair flexed forward and leaning on their palms
with arms fully extended, are usually most uncomfortable at
positions that compress the back, such as standing. Given that a
determined static position is capable of producing pain, then any
motion that causes the patient's body to pass through the POP a
multitude of times will be a most painful experience for the
patient. That is, it is the repeated coincidence with the POP over
the path of the motion that causes the pain, and not just the
motion alone. Finding and maintaining the patient's POC at the
affected level(s) and avoiding the POP should therefore be
considered essential to a successful surgery.
[0026] Many patients can move their backs physically until they
experience a POC for their spine. That is, patients may bend and
contort thereby using their spine as a lever arm about a painful
level, thereby effecting a small change in the vertebral
configuration at that level. FIGS. 1(a) and 1(b) are frontal (AP)
and lateral views of a patient's spine when in a neutral or normal
position. It will be appreciated that in order to effect a small
change in the relative position of a single vertebra with respect
to the immediately adjacent vertebrae, the spine as a whole must
bend into an extreme position to act as a lever arm about the given
vertebra. For example, FIG. 2 shows the position taken by the
neutral spine in FIG. 1(b) with full flexion applied. This results
in small changes in the positions of each level of the spine as
indicated in FIG. 2, but at the same time creates an overall
deformity of the spine.
[0027] According to the invention, one or more implant devices or
prostheses are identified which when implanted at an affected level
of a patient's spine, will urge vertebrae at the level into the
position measured at the patient's POC, and inhibit the vertebrae
from movement to the position measured at the patient's POP. For
example, if the patient's POC is such that the configuration of the
vertebrae at the affected level is one of flexion (rather than
"normal"), then a device that creates flexion is implanted at that
level. An example of such a device is the X-Stop.RTM. IPD.RTM.
System. See step 42 in FIG. 11. And, if the patient's POP is such
that the configuration of the vertebrae at the affected level is
one of flexion, then a device that will prevent flexion (e.g., the
Dynesys.RTM. Dynamic Stabilization System) is implanted. See step
44 in FIG. 11. Accordingly, the inventive system acknowledges that
patients may experience back pain even though clinical examinations
and scans of their spinal vertebrae may be normal, and the system
identifies a patient's POP as a position to avoid within any
spectrum of spinal motion that can otherwise be tolerated at the
affected level.
[0028] As mentioned, patients with back pain frequently move their
bodies into a position of comfort by contorting, bending, or
distracting their torso in order to obtain their POC, and their
position of maximal pain (the POP) often differs greatly from the
POC. When studied radiographically (with x-rays or MRI), the two
different positions may be compared, for example, by looking at the
anatomic or spatial position of each vertebra in relation to the
adjacent vertebrae. In the inventive system, the difference in
anatomic position of the vertebral bones is documented by one or
more known techniques such as x-ray or MRI, and then measured. A
slight change in the relative position of the adjacent vertebrae at
the affected level is recorded (e.g., digitally) and analyzed to
create a motion model that illustrates the positions through which
the spinal bones move from the POC to the POP. One example of a
suitable radiographic imaging device is the "EOS 3-D" available
from Biospace Med of Cambridge, Mass., US. A patient's POP and POC
may also be measured or quantified by having the patient wear
commercially available non-invasive electrogoniometers and/or
torsiometers arranged to measure the range of motion of the
patient's cervical and lumbar spine. The change of position from
the POP to the POC is preferably measured and recorded in three
planes.
[0029] FIG. 3 is an AP/frontal view of a particular patient's
lumbar spine, wherein the forces required to achieve a POC for the
patient are illustrated as vectors in the drawing. FIG. 4 is a
lateral view of the same region of the patient's spine, and also
indicates the forces needed to achieve the POC for the patient.
FIG. 5 illustrates the net change required at the affected level;
namely, a forward flexion of three degrees, and a lateral
distraction of five degrees.
[0030] Surgery is planned to transfer the patient's spinal bones
into the configuration determined for the patient's POC according
to the scans or physical measurements performed on the patient, and
to maintain the bones in the determined configuration. This is
accomplished, for example, either by fixing the bones in the
desired configuration (e.g., a spinal fusion), or by using a device
that allows motion but with such constraint as to avoid the
configuration scanned for the patient's POP (e.g., by implanting an
artificial disc replacement). For example, a patient that
demonstrates maximal pain in flexion (bending forward) should
receive a spinal implant that urges the vertebrae at the affected
level toward spinal extension (bending backward). Given the current
availability of spinal implants with various physical
characteristics, it is likely that the surgeon will be able to
select an appropriate implant in order to achieve the desired
results.
[0031] As mentioned, different spinal implants allow for certain
kinds of motion while constraining others. According to one aspect
of the invention, data representing position and motion profiles
for various spinal implants are entered into a database. See steps
30 and 32 in FIGS. 8 and 9, discussed below. A system processing
unit (see FIG. 12 and related text, below) having access to the
database then selects an optimal implant to achieve a desired
alignment of the vertebrae at the affected level of a given
patient's spine, according to image data representing scans taken
at the level for the patient's POP and POC.
[0032] In one scenario, a patient complaining of back pain is
initially evaluated to determine if surgery is medically indicated.
If so, the surgeon identifies the anatomic level(s) of the
patient's spine that are the source of the pain using, e.g., a
known discogram procedure that irritates each suspect level and
monitors patient response. As illustrated by the charts of FIGS. 6
to 11, the patient is then secured on a table (step 12) constructed
and arranged to move him or her into a number of different
positions under the control of the patient (step 14). For example,
a so-called SpineSix.RTM. table system available from MediCepts of
Stuart, Fla. 34994. See, U.S. Pat. No. 6,692,451 (Feb. 17, 2004).
The table should also be radiolucent or otherwise transparent to
radiation that is present when scanning is performed.
[0033] The patient reports his or her position of maximal
discomfort (POP) in step 16 and their position of maximal comfort
(POC) in step 22. The two table positions are recorded (steps 18
and 22) and corresponding position data is saved in a system
memory. Scans, e.g., CT scans, are taken of the affected level(s)
for at least the patient's POP (step 20) and the patient's POC
(step 24). The two scans may be visually compared with one another
by the surgeon, and corresponding image data is entered into the
system in steps 20 and 24.
[0034] In steps 26 and 28, the change in the configuration of the
patient's spine at the affected level in order for the patient to
be without pain is then determined in terms of such parameters as
spinal distraction (elongation), compression (loading), flexion
(bending forward), extension (bending backward), lateral bending,
translation and rotation. Data corresponding to the change in the
spine configuration may be produced by medical image processing
apparatus such as disclosed in, e.g., U.S. Pat. No. 7,231,073 (Jun.
12, 2007) all relevant portions of which are incorporated by
reference. Based on this data, one or more spinal implants that are
maintained in the system database are matched with the affected
level(s) of the patient's spine. See steps 34, 36 and 40 in FIGS. 9
and 10. As noted in step 38 in FIG. 10, the same data can be used
to fabricate a custom implant that will provide the forces needed
to urge the vertebrae at the affected level toward the desired
configuration at the patient's POC. Once a match is found, a
determination is made as to whether or not the implant would tend
to allow the vertebrae at the affected level to assume the
configuration scanned for the patient's POP. If so, the system
searches for other potential implants until one having the required
motion constraint is identified for the surgeon.
[0035] A significant advantage of the invention is an improved
patient outcome that results from allowing the patient to report
directly concerning his or her own POP and POC, while the surgeon
is assured of and confirms the patient's own interpretation through
objective measures such as radiography. That is, an important
feature of the inventive system resides in that the pain threshold
is allowed to be set by the patient, confirmed by the surgeon, and
documented or recorded effectively using, e.g., radiographic means
and/or a table position. The recorded information is then used
intraoperatively as a gauge to compare and judge the ideal pain
free state of the patient's spine.
[0036] A conventional surgical table may also be used to perform
the POP/POC diagnostic test. The patient may position himself or
herself preoperatively on the table immediately before surgery,
after motion control apparatus associated with the table saves or
"remembers" the patient's POC. Once the patient is under
anesthesia, the apparatus may be configured or programmed to move
the table into the position of comfort, thus guaranteeing that the
spine will be fused or fixed in the position of comfort.
[0037] An intraoperative imaging scan may be taken to check the
spinal position, and this information entered into the table
control apparatus to move the table in such a way as to recreate
the POC in the spine. Intraoperative tools for navigation (such as,
e.g., the Medtronic "Stealth" system) use input information derived
from preoperative imaging, intraoperative imaging, and reference
points acquired by the surgeon from the surgical field. The
position of comfort may also be entered into the navigation system
preoperatively, and appear as an overlay on a computer monitor
screen so that the surgeon can clearly see his/her goal to change
the position of the spinal bones into the position of comfort. Once
the POC has been achieved, the bones may be fixed or fused in that
position. Likewise, if a motion implant such as an artificial disc
is being implanted, then the surgeon can be sure the implant is
holding the spine in the desired position of comfort.
[0038] FIG. 12 is a schematic block diagram of one embodiment of a
system 100 for determining spinal implants according to the
invention, and FIGS. 13 to 25 illustrate two hypothetical case
studies or examples wherein the system 100 may be applied to
identify an implant that will obtain the best clinical result for
each patient.
Example One
[0039] Patient 1 is positioned and attached to a mobile surgical
table 102 such as, e.g., the SpineSix table mentioned above. The
patient controls the table 102 to move his/her spine into extremes
of flexion, extension, bending, rotation, distraction and
compression. The patient then manipulates the table to position
their spine in a position where he or she experiences maximum pain
(POP). The table position is recorded in terms of degrees of
flexion, extension, bending, rotation, distraction and
compression.
[0040] FIG. 13 is a radiographic image (plain x-ray) of the
patient's spine in the POP, obtained from a scanner 104 in FIG. 12.
The image, which may be taken and recorded digitally, is a plain
lateral x-ray in which selected angles of lordosis and kyphosis
associated with the motion segment are measured. In this example,
MRI images are preferred instead of plain x-rays so that anatomical
characteristics of the patient's POP and POC can be quantified once
the positions are determined.
[0041] Radiographic MRI images of the patient's spine in the POP
taken by scanner 104 are recorded, and FIG. 14 is the sagittal
(lateral) view of the MRI taken with the patient in the POP. The
lowest mobile segment (L5 S1) shows black disk on T2 weighted image
(arrow), consistent with degeneration and is therefore the presumed
spinal level of pain. Accordingly, the level with the arrow will be
addressed with spinal surgery to keep the spine positioned in the
POC as determined below, and not the POP.
[0042] Patient 1 then manipulates the table 102 to place their
spine in the position of maximum comfort (POC). The table position
is again recorded as degrees of flexion, extension, bending,
rotation, distraction and compression. This position may be
recalled during surgery. An MRI radiographic image of the spine in
the POC is taken by scanner 104 and recorded, and FIG. 15 is the
sagittal (lateral) view of the MRI taken with the patient in the
POC. The lowest mobile segment (L5 S1) shows black disc consistent
with degeneration (arrow) and is the presumed spinal level of
pain.
[0043] The recorded image data is stored and processed using
apparatus 106 such as disclosed in the mentioned '073 US patent.
The image data may be recorded and processed using established
protocols. For example, measurements may be made using so-called
OSIRIS software from the digital imaging unit at the University
Hospital of Geneva, Switzerland. Further, a so-called DICOM
(Digital Imaging and Communications in Medicine) protocol is a
known standard for handling, storing, printing and transmitting
information in medical imaging. DICOM includes a file format
definition and a network communications protocol.
[0044] The recorded images of the vertebral bones at the patient's
POP and POC reveal and quantify the change in the configuration of
the bones in terms of flexion, extension, lateral bending,
rotation, translation, compression and distraction. FIG. 16
illustrates the quantified changes in position (in degrees and
millimeters) of L5 S1 from the POP to the POC. As shown in FIG. 17,
the position changes are matched by the processing apparatus 106 to
an implant that can create the changes in the spine at level L5 S1,
wherein the implant is selected from among a number of implant
devices (e.g., artificial discs, rod/screw constructs, flexible
rods and distraction devices) whose characteristics are maintained
in a system database 108. In this example, an output 110 of the
processing apparatus 106 provides the quantified changes in
position, and an indication that patient 1 should have the best
clinical results with the above mentioned X-Stop implant which
produces a flexion/distraction force on L5 S1 while maintaining
neutral rotation.
Example Two
[0045] Patient 2 is positioned and attached to the mobile table
102. The patient controls the table 102 to move his/her spine into
extremes of flexion, extension, bending, rotation, distraction and
compression. The patient then manipulates the table to a position
where he or she experiences maximum pain (POP). The table position
is recorded in terms of degrees of spinal flexion, extension,
bending, rotation, distraction and compression.
[0046] MRI radiographic lateral and coronal images of the patient's
spine in the POP are taken separately by the scanner 104 and
recorded. FIG. 18 shows the sagittal (lateral) view of the MRI
taken with patient 2 in the POP. The image of FIG. 18 reveals
anterior shift of L4 on L5 which is consistent with instability at
that level and therefore presumed to be a spinal level of pain.
Further, the image shows a posterior shift of L5 on S1 which is
consistent with instability at that level and is therefore also
presumed to be a spinal level of pain. Accordingly, the two levels
with instability will be addressed with spinal surgery to keep the
spine positioned in a POC, and not in the POP. The POC is
determined as follows.
[0047] FIG. 19 is the coronal view of the MRI with patient 2 in the
POP. The image reveals slight right lateral bending of L4 on L5.
The patient then manipulates the table 102 to a position where
their spine is at maximum comfort or POC. The table position is
recorded as degrees of spinal flexion, extension, bending,
rotation, distraction and compression. This position may be
recalled during surgery.
[0048] An MRI radiographic lateral image of the spine in the POC is
then taken by the scanner 104 and recorded. The image in FIG. 20 is
the sagittal (lateral) view of the MRI taken with the patient in
the POC. MRI radiographic coronal images of the spine in the POC
are also taken by scanner 104 and recorded. FIG. 21 is the coronal
view of the MRI taken with the patient in the POC. The image
reveals correction to neutral of lateral bending of L4 on L5.
[0049] The recorded image data is stored and processed by the image
processing apparatus 106 as in EXAMPLE ONE. The recorded images of
the vertebral bones at the patient's POP and the POC reveal and
quantify the change in the configuration of the spinal bones in
terms of flexion, extension, lateral bending, rotation,
translation, compression and distraction.
[0050] FIG. 22 illustrates the quantified changes in position (in
degrees and millimeters) of L4-L5 from the POP to the POC in
lateral view, and FIG. 23 shows the quantified changes in position
of L4-L5 from the POP to the POC in coronal view. FIG. 24
illustrates the quantified changes in position of L5-S1 from the
POP to the POC in lateral view.
[0051] As shown in FIG. 25, the position changes in L4/L5/S1 from
the POP to the POC for patient 2 are matched by the processing
apparatus 106 to an implant that can create the changes in the
spine at levels L4/L5/S1. In this example, the output 110 of the
apparatus 106 indicates that patient 2 should have the best
clinical results with an implant that produces a posterior
compression and translation of L4 on L5, with an anterior
distraction and an anterior translation of L5 on S1. The implant
may be selected from among a number of implant devices whose
characteristics are maintained in the system database 108, or the
device may be a custom fabricated two level artificial disc
prosthesis with posterior pedicle screw motion preservation
stabilization.
[0052] The implant device(s) required to achieve the correct POC
for any patient may also be custom fabricated by way of balloons
that are placed at determined locations between the adjacent
vertebrae at each level to be treated, and then inflated to achieve
the desired correction as explained further below.
[0053] Accordingly, to achieve a patient's POC, an appropriate
implant or prosthesis device may be (i) provided as a custom
implant preconfigured to impart the required force vectors, (ii)
constructed in situ by "building" a framework within a disc space
or externally to the patient's spinal vertebrae, and/or (iii)
provided in the form of inflatable balloons constructed and
arranged to expand within or outside a disc space to produce the
required forces.
Custom Made Prosthesis to Achieve POC
[0054] Once CT scans and/or other imaging studies of a patient's
spine at the POP and the POC produce the measurements that are
needed to maintain the POC and to avoid the POP, a custom
prosthesis may be fabricated prior to surgery such as, for example,
a disc replacement device using CAD technology. Such replacement
devices may be obtained, for example, from Ranier Technology
Limited, Cambridge, UK, under the trademark Cadisc-L.RTM.. If
necessary, the prosthesis can be sectioned and then assembled in
the affected disc(s) at the time of surgery.
In Situ Constructed Prosthesis
[0055] A prosthesis may be constructed in situ by building a
framework within an affected disc space or externally to the spine
vertebrae, in order to achieve a patients POC. For example, data
corresponding to the patient's POC and the POP are obtained from
preoperative imaging studies, and entered into an intraoperative
navigation system (e.g., the mentioned Stealth system). A surgeon
or a robotic mechanism then manipulates the patient's spinal
segments into a configuration required to achieve the POC and to
avoid the POP, according to information obtained from the
navigation system based on the entered data. Once the POC is
achieved, the surgeon can use established spinal instrumentation
(e.g., screws, rods, cages, and/or plates) to maintain the
vertebral configuration required for the POC.
In Situ Constructed Prosthesis with Intraoperative Visual
Overlay
[0056] Using the data obtained from the preoperative imaging
studies, the intraoperative navigation system may be configured in
a known manner to produce image guidance overlays of the spine when
at the POP and the POC, relative to the configuration of the spine
in real time. The surgeon (or a robotic mechanism) then manipulates
the spinal vertebral bones (e.g., by adjusting pedicle screws)
until the navigation system confirms when the POC has been
achieved. Spinal implants are then used to maintain the POC. For
example, if the POC is achieved when the patient bends toward the
left, implants placed on the right side of the spine will create
distraction and produce the same forces as when the patient is
bending to the left.
Inflatable Prosthesis
[0057] An implant or prosthesis may be constructed to be
inflatable, and dimensioned to expand within or outside of a disc
space in order to produce forces required to achieve a patient's
POC. Such a prosthesis may be inserted percutaneously via a known
insertion tool or cannula, or placed in the disc space by way of
open surgery. For example, a prosthesis device 200 using two
balloons 202, 204, is shown in FIGS. 26 to 35. One balloon 202 may
be placed laterally on the (patient's) right side of a disc space
210, and then inflated to create a lateral distraction of, e.g.,
five degrees, thereby bending the spine to a patient's left and
toward the configuration required for the patient's POC. The other
balloon 204 may then be placed posterior in the disc space 210, and
then inflated to create flexion of, e.g., three degrees so as to
bend the spine forward and into the required configuration for the
patient's POC.
[0058] Inflatable balloons the same or similar to those used in the
known Kyphon.RTM. balloon kyphoplasty, wherein balloons are
inserted through cannulas into fractured vertebral bones and then
inflated to facilitate bone repair, may also be used in the
prosthesis device 200. See, e.g., U.S. Pat. Appl'n Pub. No.
2009/0299373 (Dec. 3, 2009), all relevant portions of which are
incorporated by reference. The device 200 includes an associated
insertion tool 212 that is constructed and arranged in a known
manner to introduce the balloons 202, 204 into the disc space 210
percutaneously, and to inflate the balloons, as illustrated in the
drawing.
[0059] FIG. 27 shows the balloon 202 placed laterally inside the
disc space 210, and the balloon 204 disposed posterior in the disc
space. FIG. 28 shows balloon 204 when inflated by operation of the
tool 212 to create flexion, and FIG. 29 shows balloon 202 when
inflated to create lateral bending.
[0060] As seen in FIG. 33, increased inflation of the balloon 202
will produce more lateral bending of the spine. Balloon 202 is
therefore inflated until the degree of lateral bending associated
with the patient's POC is achieved. Further, as shown in FIG. 35,
increased inflation of the balloon 204 will cause more forward
flexion. Therefore, balloon 204 is inflated until the amount of
forward flexion required for the patient's POC is achieved.
[0061] FIGS. 36 to 39 illustrate the use of multiple inflatable
balloons in a prosthesis device 300 for applying forces on
vertebral bodies 310, 312 spatially in three dimensions above and
below a patient's disc space 314, according to the invention.
[0062] As seen in FIG. 37, a ring array of four inflatable balloons
320, 322, 324, 326, and an "anchor" balloon 328 that may be of
toroidal shape when inflated, are adhered to and sandwiched between
two flexible disk shaped plates or membranes 330, 332. The plates
330, 332 are formed, for example, from a flexible silastic or
polyurethane-polycarbonate material. One or more sharp prongs or
spikes 340, 342 project from the outwardly facing surfaces 330a,
332a of the plates in regions above and below the body of the
anchor balloon 328. Each of the balloons 320 to 328 has an
associated filling tube 320a to 328a through which the balloon may
be inflated with a liquid substance or cement dispensed from an
associated syringe or computer controlled infusion pump at a
proximal end of the filling tube. Alternatively, as shown in FIG.
36, the proximal ends of the filling tubes 320a to 328a may be
coupled to a filling tube selector 356 that is constructed and
arranged in a known manner to enable a given substance contained in
a syringe 358 to be channeled into selected ones of the tubes. The
selector 356 is preferably also configured to receive syringes
containing other substances to be channeled to selected filling
tubes.
[0063] The plates 330, 332 are rolled with the deflated balloons
320 to 328 and their associated filling tubes 320a-328a so as to
acquire a profile small enough to be passed axially through an
outer tube 350, and inserted percutaneously into the patient's disc
space 314 when exiting the distal end of the outer tube 350. To
achieve a correct orientation, radiographic or visual markers may
be incorporated on the balloons and/or other parts of the device
300 when inserted in the disc space. The balloons are then inflated
selectively with air, water, or other liquid substance to allow
flexibility, or with a cement to provide rigidity. The inflation
process may also serve at least in part to unroll the plates 330,
332 with the balloons inside the disc space 314.
[0064] Once inserted in the patient's disc space 314, the anchor
balloon 328 is preferably inflated first. As the latter expands,
the outwardly projecting spikes 340, 342 on the plates 330, 332 are
forced into vertebral end plates 310a, 312a above and below the
disc space 314, while the deflated balloons 320 to 326 remain in
place at determined positions in the disc space. Once the anchor
balloon 328 is fully inflated, it forms an open central region 316
inside the disc space 314. If only one pair of spikes 340, 342 are
each centrally located on a corresponding plate 330, 332 in axial
alignment with one another, then the remaining deflated balloons
320 to 326 may be placed at desired positions inside the disc space
by turning the plates about the axis of the spikes 340, 342.
[0065] The remaining balloons are inflated individually with air,
water or other liquid substance, or cement through their filling
tubes by operating the associated filling syringes or infusion
pumps, or by using the filling tube selector 356 and an associated
syringe 358. Each balloon is inflated by an amount sufficient to
displace the vertebral end plates 310a, 312a above and below the
balloon by a determined distance so that when all the balloons are
inflated, the affected level of the patient's spine is urged into a
position that achieves the patient's POC. Once the POC is achieved,
the vertebral bodies 310, 312 are fused to one another by inserting
cement, bone fragments, a bone substitute (e.g., BMP), or new
biologic material into the open central region 316 formed by the
anchor balloon 328. The central region 316 is preferably filled
through a separate tube (not shown in the drawing), while the
anchor balloon 328 remains inflated to ensure that the prongs 340,
342 will stay in place in the vertebral bodies 310, 312 and thereby
prevent the balloons from migrating.
[0066] As mentioned, the proximal ends of the balloon filling tubes
320a to 328a may all be coupled to the filling tube selector 356 to
allow a substance contained in a replaceable syringe 358 to be
channeled through selected ones of the filling tubes. For example,
water may be channeled into the filling tube of a selected balloon
or balloons so as to move the vertebral bones of an awake patient
to find his or her POC. Once the POC is achieved, an associated
computer or processor may be configured to determine a quantity of
bone cement needed to expand the same balloons to the same
dimensions as when expanded by the water. The water is then
expelled from the balloons, and the determined amount of cement is
pumped into the balloons after coupling a different syringe to the
selector 356. Different syringes or infusion pumps, each supplying
a different inflation substance or cement, may also be permanently
coupled to the filling tube selector 356 so that when a given
syringe or pump is operated, its associated substance is channeled
through the selected balloon filling tube.
[0067] While the foregoing represents preferred embodiments of the
invention, it will be understood by those skilled in the art that
various modifications and changes may be made without departing
from the spirit and scope of the invention. For example, in spine
surgery, "biologics" are substances that can be injected into
degenerative discs to restore and regenerate the disc to a healthy
form. An implant or prosthesis determined and placed according to
the invention may be used to hold a patient's spine in his or her
POC, similar to a splint, until the biologic material is
incorporated and disc healing has occurred. The implant may then be
removed or dissolve over time, leaving a natural healthy disc. It
is contemplated that the ability of biologics to reduce pain will
be enhanced if the spine is held in the patient's POC while their
body incorporates the biologic substance and heals. The material
forming the implant device or prosthesis can therefore be made of a
resorbable material that needs to last only long enough for the
injected biologic substance to take hold.
[0068] Accordingly, the invention includes all such modifications
and changes as come within the scope of the appended claims.
* * * * *