U.S. patent application number 12/823657 was filed with the patent office on 2010-10-14 for flexible rod manufacturing apparatus and method for a spinal fixation and the flexible rod manufactured through the same.
Invention is credited to Kyung-Woo PARK.
Application Number | 20100262189 12/823657 |
Document ID | / |
Family ID | 39170697 |
Filed Date | 2010-10-14 |
United States Patent
Application |
20100262189 |
Kind Code |
A1 |
PARK; Kyung-Woo |
October 14, 2010 |
FLEXIBLE ROD MANUFACTURING APPARATUS AND METHOD FOR A SPINAL
FIXATION AND THE FLEXIBLE ROD MANUFACTURED THROUGH THE SAME
Abstract
The present invention relates to a rod capable of securely
connecting pedicle screws in a pedicle screw system for correcting
a damaged or transformed spine and a method and an apparatus for
fabricating the same and, more particularly, to a flexible pedicle
rod with superelasticity in order to provide a flexibility to a
fixation between spine segments and a method and an apparatus
capable of fabrication the same in mass production. The apparatus
according to the present invention comprises a body; an X- and
Y-axis moving element mounted on a top surface of the body, the X-
and Y-axis moving element simultaneously moving in X-axis and
Y-axis directions to wind a material at an angle of 90 degrees; a
magazine mounted on the X- and Y-axis moving element to load a
material; a material withdrawing element for withdrawing materials
one by one from the magazine; and a material molding element
mounted on the X- and Y-axis moving element, the material molding
element gripping both ends of the material withdrawn from the
material withdrawing element and rotating to mold a portion of the
material in a spring shape.
Inventors: |
PARK; Kyung-Woo; (Seoul,
KR) |
Correspondence
Address: |
LOWE HAUPTMAN HAM & BERNER, LLP
1700 DIAGONAL ROAD, SUITE 300
ALEXANDRIA
VA
22314
US
|
Family ID: |
39170697 |
Appl. No.: |
12/823657 |
Filed: |
June 25, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11851104 |
Sep 6, 2007 |
7765843 |
|
|
12823657 |
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Current U.S.
Class: |
606/254 |
Current CPC
Class: |
A61B 17/7011 20130101;
A61B 17/7028 20130101; A61B 2017/00867 20130101 |
Class at
Publication: |
606/254 |
International
Class: |
A61B 17/70 20060101
A61B017/70 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 7, 2006 |
KR |
10-2006-0086345 |
Claims
1-10. (canceled)
11. A flexible pedicle rod comprising: a straight-line portion,
wherein one end of the straight-line portion is formed on a
straight line and the other end of the straight-line portion is
formed on the same straight line; and a spring-shaped elastic
portion wound in a spiral shape at a predetermined portion between
the straight-line portions, wherein the elastic portion and the rod
body are formed to be eccentric by a predetermined interval.
12. A flexible pedicle rod prepared by a process comprising: a
first step of initializing; a second step of driving a feeder
driving motor to move a feeder straight in the initialization
state, thereby withdrawing a material from a magazine; a third step
of gripping one end of the material moving straight by the feeder
at the die; a fourth step of driving an Y-axis servo motor built in
a body to move an Y-axis stage straight, thereby fixing the other
end of the material to a groove shaft of a fixing base; a fifth
step of driving a high-frequency heater to heat the material at a
predetermined temperature; a sixth step of respectively driving
Y-axis and X-axis servo motors in Y-axis and X-axis directions to
wind the material fixed to the die and the groove shaft at 90
degrees; a seventh step of driving the X-axis servo motor to move
an X-axis stage in the X-axis direction, and driving a rotating
motor mounted on the X-axis stage to wind the material fixed to the
fixing base on a spiral line and wind the material in a coil shape;
and an eighth step of discharging the material.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a rod capable of securely
connecting pedicle screws in a pedicle screw system for correcting
a damaged or transformed spine and a method and an apparatus for
fabricating the same and, more particularly, to a flexible pedicle
rod with superelasticity in order to provide flexibility to a
fixation between spine segments and a method and an apparatus
capable of fabricating the same in mass production.
[0002] Generally, when the spine undergoes bad environments of
artificial factors and degenerative spine disease and is maintained
in abnormal postures for a long time, serious back pain is induced
by the press of the nerve system passing through the spinal
canal.
[0003] In general, in the case where the conservative treatment has
an effect on the patients with degenerative spine disease, the
patients need the surgical treatment. Particularly, a spinal fusion
treatment is carried out in spinal stenosis, spondylolisdthesis and
spondylolysis accompanying instability between spinal segments. A
conventional surgical treatment to use a rigid rod, which does not
have mobility at all, gives rise to many side effects on the
patients as time goes on. Therefore, a pedicle fixing apparatus is
to be inserted into an injured or wrenched site of the spine in
order that the injured or wrenched site is neither suppressed nor
is ruined or the part thereof is not pressed or pushed down.
[0004] As shown in FIGS. 1 and 2, a conventional pedicle fixing
apparatus includes a plurality of pedicle screws 200 which are
respectively inserted, as a supporting member, through the pedicle
into injured or deformed vertebra, wherein each of the pedicle
screws 200 has a head 201 with a U-shaped rod passage 201a; rods
250 for making a correction of the pedicle through an
interconnection between the pedicle screws 200; set screws 300 to
be inserted into the rod passage 201a for fixing the rods 250; and
a transverse link 400 for holding a pair of the rods 250.
[0005] In the pedicle fixing apparatus of FIG. 1, the rod plays an
important role in the fixation of the deformed vertebra. Therefore,
the quality of the material, elasticity, and so on, of the rod has
a significant influence on the human body.
[0006] Since most conventional rods are formed out of a titanium
material for a medical treatment, the rods themselves do not have
elasticity. There is a problem in that it is difficult to maintain
a normal waist curve because the fusion of the spine segments is
conducted according to the shape of the rod after the surgical
spine correction. Moreover, after the spine completely fuses to the
arrangement form of the rod, since a load is concentrated on the
upper segment or the lower segment of the spine into which the
pedicle screws are inserted, instability and another stenosis can
be caused after several years.
[0007] To solve the demerit of the rigid rod, various methods to
partially provide elasticity to a part of the rod have been
introduced. Particularly, in order to solve the demerit of the
conventional rods effectively and to make the surgical correction
of spinal deformity easy, the applicant of the present invention
introduced a rod for the pedicle fixation using a shape memory
alloy such as a Ni--Ti alloy (Nitinol) which is harmless in the
human body with high congeniality and has the property similar to
the human tissue in superelasticity and absorption nature. For
example, the various rods have been introduced in Korean patent
application Nos. 2004-76105, 2004-76106, 2004-97833 and
2004-97834.
[0008] As shown in FIGS. 3a and 3b, a rod (600) described in the
cited references has a body 602 and an elastic member 604, which
has a coil type formed in the middle of the body 602, to provide
the flexibility to the rod 600. This flexible rod has a length of
approximately 80 to 100 mm (typically, 82 mm) and a small standard
diameter of approximately 3 to 6 mm. Since the material of the rod
itself is to have the hard metal organization and the rod is to be
manufactured in a coil type with the shape memory through a heating
process, it is very difficult to form the elastic member of the
coil type in the middle of the rod. The rod having the coil section
is manually made due to the drawback to the manufacture of the rod;
however, it is very difficult to make the rod uniform and it is
impossible to realize the mass production and
commercialization.
[0009] On the other hand, when the surgical correction of spinal
deformity, in which two parts of the rod body are different from
each other in height, is performed, the elastic member having a
large volume causes a surgical inconvenience in the procedure of
securing the rod within the pedicle screw because the body
described in the cited references is positioned at the central axis
of the elastic member and then the pedicle can be in contact with
the elastic member. In this case, there is a problem in that an
inevitable operation procedure which has to dig a space out of the
spine is required.
SUMMARY OF THE INVENTION
[0010] Embodiments of the present invention are directed to
providing an apparatus for fabricating a flexible rod of a pedicle
screw system in mass production, wherein the fixation between
spinal segments is improved after the surgical correction of spinal
deformity and superelasticity is provided for a part of the
flexible rod in order that an elastic power is induced when an
external force is applied to the spine.
[0011] Also, embodiments of the present invention are directed to
providing a rod of a pedicle screw system, which has no
interference from a elastic section of the rod in the surgical
correction of spinal deformity, by providing eccentricity between a
rod body and the elastic section.
[0012] According to an aspect to the present invention, there is
provided an apparatus for fabricating a flexible pedicle rod for
pedicle fixation, the apparatus comprising a body; an X- and Y-axis
moving element mounted on a top surface of the body, the X- and
Y-axis moving element simultaneously moving in X-axis and Y-axis
directions to wind a material at an angle of 90 degrees; a magazine
mounted on the X- and Y-axis moving element to load a material; a
material withdrawing element for withdrawing materials one by one
from the magazine; and a material molding element mounted on the X-
and Y-axis moving element, the material molding element gripping
both ends of the material withdrawn from the material withdrawing
element and rotating to mold a portion of the material in a spring
shape.
[0013] According to another aspect to the present invention, there
is provided a method for fabricating a flexible pedicle rod for
pedicle fixation, the method comprising a first step of
initializing; a second step of driving a feeder driving motor to
move a feeder straight in the initialization state, thereby
withdrawing a material from a magazine; a third step of gripping
one end of the material moving straight by the feeder at the die; a
fourth step of driving an Y-axis servo motor built in a body to
move an Y-axis stage straight, thereby fixing the other end of the
material to a groove shaft of a fixing base; a fifth step of
driving a high-frequency heater to heat the material at a
predetermined temperature; a sixth step of respectively driving
Y-axis and X-axis servo motors in Y-axis and X-axis directions to
wind the material fixed to the die and the groove shaft at 90
degrees; a seventh step of driving the X-axis servomotor to move an
X-axis stage in the X-axis direction, and driving a rotating motor
mounted on the X-axis stage to wind the material fixed to the
fixing base on a spiral line and wind the material in a coil shape;
and an eighth step of discharging the material.
[0014] According to still another aspect to the present invention,
there is provided a flexible pedicle rod prepared by a process
comprising a first step of initializing; a second step of driving a
feeder driving motor to move a feeder straight in the
initialization state, thereby withdrawing a material from a
magazine; a third step of gripping one end of the material moving
straight by the feeder at the die; a fourth step of driving an
Y-axis servo motor built in a body to move an Y-axis stage
straight, thereby fixing the other end of the material to a groove
shaft of a fixing base; a fifth step of driving a high-frequency
heater to heat the material at a predetermined temperature; a sixth
step of respectively driving Y-axis and X-axis servo motors in
Y-axis and X-axis directions to wind the material fixed to the die
and the groove shaft at 90 degrees; a seventh step of driving the
X-axis servo motor to move an X-axis stage in the X-axis direction,
and driving a rotating motor mounted on the X-axis stage to wind
the material fixed to the fixing base on a spiral line and wind the
material in a coil shape; and an eighth step of discharging the
material.
[0015] According to still another aspect to the present invention,
there is provided a flexible pedicle rod comprising a straight-line
portion, wherein one end of the straight-line portion is formed on
a straight line and the other end of the straight-line portion is
formed on the same straight line; and a spring-shaped elastic
portion wound in a spiral shape at a predetermined portion between
the straight-line portions, wherein the elastic portion and the rod
body are formed to be eccentric by a predetermined interval.
[0016] As described in one embodiment of the present invention, a
major feature of the present invention is to produce in large
quantities of pedicle rods each having a coil-shaped elastic
portion from the conventional rigid rod with no elasticity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The above and other aspects, features and other advantages
of the subject matter of the present disclosure will be more
clearly understood from the following detailed description taken in
conjunction with the accompanying drawings, in which:
[0018] FIG. 1 is a perspective view of a conventional pedicle
fixing apparatus having a pedicle screw system for a surgical
correction of spinal deformity;
[0019] FIG. 2 is a perspective view of a conventional pedicle
fixing apparatus installed in vertebrae lumbales;
[0020] FIGS. 3a and 3b are views illustrating flexible pedicle rods
used in the conventional pedicle fixing apparatus;
[0021] FIGS. 4 to 6 are front, right lateral and left lateral views
of an apparatus for fabricating a flexible pedicle rod according to
the present invention;
[0022] FIG. 7 is a flow chart illustrating a method for fabricating
the flexible pedicle rod according to the present invention;
[0023] FIG. 8 is a schematic view illustrating a fabricating
procedures of the flexible pedicle rod according to the present
invention; and
[0024] FIG. 9 is a perspective view of the flexible pedicle rod
according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] Hereinafter, exemplary embodiments of the present invention
will be described with reference to accompanying drawings.
[0026] A apparatus and a method for fabricating a flexible pedicle
rod for pedicle fixation according to one embodiment of the present
invention are implemented to produce in large quantities of pedicle
rods in the state that a superelastic force is applied to a portion
of each of the pedicle rods.
[0027] A material for a pedicle rod used for the apparatus
according to the one embodiment of the present invention is
fabricated using a shape-memory alloy that does not harm human
beings in various types of shape-memory alloys, particularly
Nitinol (i.e., Ni--Ti alloy). The present invention is not limited
to a pedicle rod using Nitinol. That is, a metal that does not harm
human beings, e.g., a titanium-based metal (including an alloy), a
stainless 316 (SUS 316) metal or the like may also be used to
fabricate a pedicle rod according to one embodiment of the present
invention.
[0028] As illustrated in FIGS. 4 to 6, an apparatus for fabricating
a flexible pedicle rod includes a body 2 having a Y-axis servo
motor (not shown) built therein; a Y-axis stage 4 mounted on a top
surface of the body 2 to move in a Y-axis direction by means of a
driving force of the Y-axis servo motor; an X-axis servo motor 6
mounted on one side of the body 2; an X-axis stage 8 mounted on the
Y-axis stage 4 to move in an X-axis direction by means of a driving
force of the X-axis servo motor; a magazine 10 mounted on the
Y-axis stage 4 at a predetermined inclination angle to load a
material; a feeder 12 mounted at a rear end of the magazine 10 to
withdraw materials loaded to the magazine 10 by moving them forward
one by one; a feeder driving motor 14 for providing rotation power
to the feeder 12 such that the feeder 12 can move forward; a first
timing belt 15 for connecting between the feeder 12 and the feeder
driving motor 14 to deliver power; a die 16 mounted in front of the
feeder 12 to grip a rear end of a material supplied by means of the
operation of the feeder 12; a high-frequency heater 18 mounted at
one side of the feeder 12 to provide a predetermined heat source to
a material through a coil 18a wound on an outer circumferential
surface of the die 16 and then moving to a heating position of the
material by means of a driving force of the Y-axis servo motor 6; a
fixing base 20 mounted on the Y-axis stage 4 and having a groove
shaft 20a mounted at a front side of the fixing base 20, the groove
shaft supporting a material by fixing the other end of the material
thereto; a C-axis motor 22 for providing a rotation force to the
fixing base 20 to wind a material in a spiral shape; a second
timing belt 23 for connecting between the groove shaft 20a of the
fixing base 20 and the C-axis motor 22 to deliver power; and a
cylinder 24 mounted at a rear of the fixing base 20 to discharge a
molded material from the groove shaft 20a by moving straight toward
the groove shaft 20a. Reference numeral 26 denotes a controller
panel.
[0029] In the aforementioned configuration, since the C-axis motor
22 is positively and reversely rotatable, an elastic portion formed
in the material can be molded in the shape of a string wound in a
left or right direction.
[0030] Hereinafter, fabricating processes using the apparatus for
fabricating a flexible pedicle rod according to the one embodiment
of the present invention will be described in detail with respect
to FIGS. 7 and 8.
[0031] First, a power source switch (not shown) mounted on the
controller panel 26 is turned on, thereby initializing the
apparatus (S10). If the feeder driving motor 14 is operated after
loading a material to the magazine 10 in the initial state of the
apparatus, the feeder 12 moves straight to withdraw the material
toward the die 16 (S20). One end of the withdrawn material is
gripped by the die 16, and the other end of the withdrawn material
is fixed to the groove shaft 20a of the fixing base 20 opposite to
the die 16 on an axis line, thereby completing the setup of the
material (S30) ((a) to (d) of FIG. 8).
[0032] In the embodiment of the present invention, an interval at
which both ends of the material are gripped is about 15 mm.
[0033] After completing the step S30, the high-frequency heater 18
and the coil 18a of the high-frequency heater 18 heat the material
withdrawn from the die 16 while moving by means of the operation of
the Y-axis servo motor (S40) ((c) and (d) of FIG. 8). At this time.
The temperature at which the material is heated by the
high-frequency heater 18 is about 600 to 700.degree. C. If the
heating temperature of the material is 600.degree. C. or less, it
is difficult to obtain a molded product having a desired shape. If
the heating temperature of the material is 700.degree. C. or more,
a change in property of the material may be caused.
[0034] When the heating of the material is completed, the Y-axis
and X-axis servo motors are simultaneously driven. Accordingly, the
Y-axis and X-axis stages 4 and 8 move in the Y-axis and X-axis
directions, respectively. Through the operations of the Y-axis and
X-axis stages 4 and 8, the X-axis stage 8 is rotated in a direction
of 90.degree. about the die 16, and the material having both ends
fixed to the die 16 and the groove shaft 20a of the fixing base 20
is primarily bent at an angle of 90.degree. (S50) ((e), (f) and (g)
of FIG. 8).
[0035] After completing the primary winding of the material, the
C-axis motor 22 is rotated and driven, and the X-axis stage 8 moves
and rotates the material three times on a spiral line, thereby
performing a secondary winding (S60) ((h) and (i) of FIG. 8).
Through the operation, the material forms an elastic portion in a
spring shape through. At the step S50, since the C-axis motor 22 is
positively and reversely rotatable, the elastic portion forms a
spring wound in a right screw direction in a positive rotating
operation, and forms a spring wound in a left screw direction in a
reverse rotating operation.
[0036] After completing the spring molding of the material, a
gripping force is eliminated from the die 16 ((j) of FIG. 8). The
Y-axis stage 4 moves by driving the Y-axis motor, thereby leaving
the material from the die 16. If the cylinder 24 moves straight to
pass through the groove shaft 20a of the fixing base 20, the molded
material fixed to the groove shaft 20a is discharged (S70) ((k) of
FIG. 8).
[0037] After discharging the material as described above,
compressed air is provided to the die 16 from the outside, thereby
cooling the die 16 (S80).
[0038] As illustrated in FIG. 9, a flexible pedicle rod 30
fabricated through the aforementioned configuration and fabricating
method includes a rigid rod body 31 having a straight line shape
and a flexible elastic portion 32 having a spring shape. At this
time, the pedicle rod 30 is formed into an eccentric structure in
which the center of the rod body 31 has a predetermined deviation t
with respect to the center of the elastic portion 32. Since the
heights of screws implanted into a pedicle are different from one
another in a vertebral pedicle correcting operation, the pedicle
rod 30 prevents the elastic portion 32 from being interfered by the
pedicle when the pedicle rod 30 is seated on the pedicle. That is,
when the pedicle rod 30 is fabricated in the state that the center
of the rod body 31 is positioned on the same line with respect to
the center of the elastic portion 32, a circumferential surface of
the elastic portion 32 contacts the pedicle in the process of
seating the pedicle rod 30 into a receiving groove of each of the
screws with different heights. For this reason, it is difficult to
seat the pedicle rod 30, and a vertebral bone may be unavoidably
cut down by an interval at which the elastic portion 32 contacts
the pedicle. However, since the elastic portion 32 can face upward
in the pedicle rod 30 having eccentricity as described in the one
embodiment of the present invention, interference between the
elastic portion 32 and the pedicle does not occur.
[0039] In addition, since the flexible pedicle rod 30 is flexible
only at the elastic portion 32 and the rod body 31 is a rigid part,
three-dimensional flexibility can be provided even though an error
occurs in the process of connecting the pedicle rod 30 after the
implant of the pedicle screws.
[0040] As described above, according to one embodiment of the
present invention, a pedicle rod having a relatively short length
and a rigid property is provided with a flexible elastic portion,
and it is possible to produce in large quantities of pedicle rods
with such a structure, so that the pedicle rods can be remarkably
commercialized in a pedicle correcting operation.
[0041] The pedicle rod provided with an elastic portion fabricated
according to one embodiment of the present invention is deformed at
a predetermined temperature and formed of a memory-shape alloy
(nitanol) with superelasticity so that flexibility and durability
can be maximized, and an operation can be easily performed due to
flexibility caused at a deformation temperature of 10.degree. C. or
less, possessed by the shape-memory alloy. Further, the present
invention provides a pedicle fixing apparatus using a pedicle rod
provided with an elastic portion and a noble connection method for
fixing the pedicle rod with segments, so that instability between
spinal segments are cured, and exercise between the spinal segments
can be maintained. In addition, a side effect of an operation using
the conventional rigid rod can be reduced, and an operation can be
easily performed.
[0042] Although preferred embodiments of the present invention have
been described for illustrative purposes, those skilled in the art
will appreciate that various modifications, additions and
substitutions are possible, without departing from the scope and
spirit of the invention as disclosed in the accompanying
claims.
* * * * *