U.S. patent application number 12/008913 was filed with the patent office on 2008-05-15 for instrument for placement and distraction of an implant.
This patent application is currently assigned to Ulrich GmbH & Co. KG. Invention is credited to Patrick Kluger.
Application Number | 20080114371 12/008913 |
Document ID | / |
Family ID | 33103631 |
Filed Date | 2008-05-15 |
United States Patent
Application |
20080114371 |
Kind Code |
A1 |
Kluger; Patrick |
May 15, 2008 |
Instrument for placement and distraction of an implant
Abstract
An instrument for the placement and distraction of an implant
for intersomatic fusion of two adjacent vertebrae comprises a
hollow rod connected with a handle, and having a pivotable setting
element at a front, free end. The element has two pins for
insertion into two guide grooves assigned to a longitudinal parting
in the implant. There is a sleeve disposed on the hollow rod and
connected with a pivot lever which activates a tension piece that
engages on the setting element, for pivoting. A hollow screwdriver
is arranged in the hollow rod, and a threaded pin to be screwed
into a threaded bore of a screw head of a locking screw on the
implant passes through the screwdriver.
Inventors: |
Kluger; Patrick; (Erbach,
DE) |
Correspondence
Address: |
COLLARD & ROE, P.C.
1077 NORTHERN BOULEVARD
ROSLYN
NY
11576
US
|
Assignee: |
Ulrich GmbH & Co. KG
|
Family ID: |
33103631 |
Appl. No.: |
12/008913 |
Filed: |
January 15, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10854650 |
May 26, 2004 |
|
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12008913 |
Jan 15, 2008 |
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Current U.S.
Class: |
606/99 ;
606/90 |
Current CPC
Class: |
A61F 2002/4629 20130101;
A61F 2250/0009 20130101; A61F 2002/4627 20130101; A61F 2/446
20130101; A61F 2002/30556 20130101; A61F 2310/00023 20130101; A61F
2002/3055 20130101; A61F 2002/30507 20130101; A61F 2230/0069
20130101; A61F 2002/30881 20130101; A61F 2220/0025 20130101; A61F
2002/30601 20130101; A61F 2002/448 20130101; A61F 2310/00353
20130101; A61F 2002/4635 20130101; A61F 2002/30237 20130101; A61F
2/4611 20130101; A61F 2310/00017 20130101 |
Class at
Publication: |
606/099 ;
606/090 |
International
Class: |
A61B 17/58 20060101
A61B017/58 |
Foreign Application Data
Date |
Code |
Application Number |
May 27, 2003 |
DE |
103 24 319.4 |
Claims
1. An instrument for the placement and distraction of an implant
for intersomatic fusion of two adjacent vertebrae, said implant
comprising a first implant part and a second implant part being
adjustable relative to the first implant part, for the purpose of
distraction, wherein the first implant part and the second implant
part supplement one another, in a complementary manner, in a
non-distracted state, to form a pipe that is divided in a
longitudinal direction, and wherein there are guide surfaces
disposed on the first and second implant parts, said guide surfaces
extending radially in a distraction direction and resting against
one another, and means for fixing the relative position of the
guide surfaces in place, said instrument comprising: a hollow rod
connected with a handle, said rod having a pivotable setting
element at a front, free end, which element has two pins for
insertion into two guide grooves assigned to a longitudinal parting
in the implant; a sleeve disposed on the hollow rod and being
connected with a pivot lever, said pivot lever activating a tension
piece that engages on the setting element, for pivoting; and a
hollow screwdriver arranged in the hollow rod through which
screwdriver a threaded pin to be screwed into a threaded bore of a
screw head of a locking screw on the implant passes.
2. An instrument according to claim 1, wherein a rod thread is
formed on a back end of the hollow rod, with a threaded ring
arranged on said rod thread, to limit a setting path of the
sleeve.
3. An instrument according to claim 1, wherein the tension piece
engages at a top end of the setting element, wherein projections
are formed on the hollow rod, in a front region, at opposite rod
walls, which projections define a pivot axis that lies
perpendicular to a longitudinal parting of the implant, and wherein
the setting element rests against the projections at a distance
from a connection with the tension piece.
4. An instrument according to claim 1, wherein a stirrup is mounted
on a handle of the instrument, said stirrup adapted to be pivoted
between a position that limits an axial adjustment path of the
threaded pin, and a position that eliminates this limitation.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 10/854,650, filed on May 26, 2004, which claims priority
under 35 USC .sctn.119 of German Application No. DE 103 24 319.4,
filed on May 27, 2003.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to an implant for intersomatic fusion
of two adjacent vertebrae, having a first implant part and a second
implant part that is adjustable relative to the former, for the
purpose of distraction.
[0004] 2. The Prior Art
[0005] Implants for intersomatic fusion of two vertebrae are used
in order to stabilize a segment of the spinal column after the
resection of a disk that was considered necessary. In the case of
the operating method, a differentiation is made between operating
techniques, with regard to access to the spinal column from the
back or from the abdominal side, and fundamentally, different
general conditions apply for these. In the case of access that
takes place from the posterior direction, the spinal cord must be
pushed out of the operation region as gently as possible, for the
necessary measures for removing the disk, preparing the vertebrae,
and inserting the implant to be carried out in the immediate
vicinity of the spinal cord, and for the operator to make do with
little room.
SUMMARY OF THE INVENTION
[0006] It is therefore an object of the invention to develop an
implant of the type stated above in such a manner that the
construction form can be made smaller, in particular, the length
can be reduced, while completely maintaining the distraction
possibility and simple operation of the implant for distraction in
the operating field, in situ.
[0007] In the invention, the first implant part and the second
implant part are structured so that they supplement one another, in
a complementary manner, in the non-distracted state, to form a pipe
that is divided in the longitudinal direction. Guide surfaces that
extend radially in the distraction direction and rest against one
another are formed on the first implant part and the second implant
part. Means are provided for fixing the relative position of the
guide surfaces in place.
[0008] Such an embodiment of an implant has the advantage that
because of the pipe-shaped configuration of the implant in the
basic state, as well as the distraction that takes place
perpendicular to the pipe axis, a very stable implant that
withstands great stress is produced, which can have small
dimensions in the distraction direction, in the case of a short but
appropriate expanse in the longitudinal direction, so that there is
only a small need for space when introducing the implant past the
spinal column, between the vertebrae. In this connection, the guide
surfaces ensure that a precisely defined movement progression takes
place in the adjustment of the two implant parts relative to one
another. The guide surfaces are used, at the same time, in order to
permanently fix a relative position of the two implant parts in
place once it has been achieve. This, in turn, promotes the compact
construction form of the implant, since no additional, extensive
structures are needed to prevent the two implant parts from
becoming incorrectly placed relative to one another.
[0009] It has proven to be advantageous if the pipe has a circular
cross-sectional shape in the non-distracted state, and forms a
cylinder. The cylinder is characterized by its simple geometrical
shape, which is easy to produce, and is connected with a great
ability to withstand stress.
[0010] According to a particularly preferred embodiment of the
invention, the guide surface of the first implant part is formed on
its face, and that the guide surface of the second implant part is
formed in a radially running slit, namely on the inside of a face
plate. This achieves the result that the components that are
required for the precise adjustment of the two implant parts, as
well as for their reciprocal fixation in place, extend radially
from the surface of the pipe towards the inside, and therefore no
increased need for space is required for these components during
insertion of the implant.
[0011] The slit preferably widens radially, in the direction of the
first implant part. The face plate is preferably formed in two
parts with the second implant part and is adjustable in the axial
direction. The guide surface of the first implant part is
preferably formed on a guide wedge that engages into the slit,
having wedge walls that run parallel to the slit walls. By means of
this configuration, the relative position of the two implant parts
relative to one another can be fixed in place by means of jamming,
and can be released again. A reinforcement of the fixation occurs
by means of the slit and by means of the guide wedge if the implant
is placed under stress, since the guide wedge is pressed into the
slit and increases the contact pressure between the guide surfaces
with its wedge walls, and thereby increases the frictional
engagement.
[0012] Since a displacement of the two implant parts relative to
one another in the axial direction also occurs during an adjustment
of the two implant parts relative to one another in the distraction
direction, because of the inclined configuration of the slit walls
and the wedge walls, an axially running guide groove is formed in
the face plate, for interaction with a guide tab formed on the
second implant part. In this way, the axial adjustment of the two
implant parts relative to one another also takes place in precisely
defined manner.
[0013] In order to achieve the greatest possible length of the
guide surface, the guide wedge is formed, in the circumference
direction, as a ring open on one side, which surrounds the guide
tab with its ring opening in the non-distracted state.
[0014] With regard to a low need for space, it is advantageous if
an axially running threaded bore is formed in the face plate, on
the side that faces inward, and a ring eye is formed on the second
implant part, to hold a locking screw that engages in the threaded
bore, as means for fixing the relative position of the first
implant part and the second implant part in place. Fixation of the
two implant parts in place can take place simply by turning the
locking screw in the threaded bore, or they can be released again,
whereby it should be noted that in order to activate the means for
fixation, access to the implant merely has to be provided in the
axial direction, in other words in the direction in which the space
is already available, through which the implant was introduced into
its position.
[0015] Simple access to the locking screw is achieved in that an
implant opening for access into the interior of the implant is
formed on the side opposite the face.
[0016] A plurality of guide grooves is formed in the implant
opening, two of which run along the longitudinal parting between
the first implant part and the second implant part. These guide
grooves are provided, in this connection, in order to offer the
operator an access possibility for adjusting the two implant parts,
in precisely defined manner.
[0017] If a threaded bore is formed in the free end of the screw
head of the locking screw, then there is the possibility of
absorbing tensile forces that act on the implant by screwing in a
threaded pin, and thereby counteracting a change in the position of
the implant, as a whole, during distraction.
[0018] Secure anchoring of the implant in the surfaces of the
adjacent vertebrae that lie against the implant is promoted in that
the surfaces of the pipe that lie opposite one another in the
distraction direction have teeth. It is furthermore advantageous if
the first implant part and the second implant part are made of
surgical steel and/or titanium.
[0019] Alternatively or additionally, bone cement that is
introduced between the first implant part and the second implant
part is also suitable as a means of fixation.
[0020] An instrument that is particularly suitable for placement
and distraction of the implant comprises a hollow rod connected
with a handle, which rod has a pivotable setting element at its
front, free end. The element has two pins for insertion into the
two guide grooves assigned to the longitudinal parting. On the
hollow rod, a sleeve is connected with a pivot lever, which serves
for activating a tension piece that engages on the setting element,
for pivoting. A hollow screwdriver is arranged in the hollow rod,
through which screwdriver a threaded pin to be screwed into the
threaded bore of the screw head passes. The implant can be set onto
this instrument, in simple manner, in that the pins are inserted
into the guide grooves and the screwdriver, together with the
threaded pin, is brought into contact with the screw head, in such
a manner that the threaded pin is screwed into the threaded bore in
order to absorb tensile forces, and the screwdriver rests against
the screw head only with a positive lock, in usual manner, in order
to be able to exert rotation forces onto the screw. After the
locking screw has been loosened, the two guide surfaces of the two
implant parts can be displaced relative to one another. The
displacement is brought about by operating the pivot lever, which
brings about a rotation of the setting element, which produces
spreading of the guide grooves perpendicular to the longitudinal
parting, with the resulting adjustment of the two implant parts
relative to one another. This adjustment, once it has been
achieved, can be fixed in place again by activating the locking
screw, using the screwdriver.
[0021] In order to obtain the greatest possible control during the
distraction, it is provided that a rod thread is formed on the back
end of the hollow rod, with a threaded ring arranged on it, to
limit the setting path of the sleeve.
[0022] The tension piece engages at the top end of the setting
element. Projections are formed on the hollow rod, in the front
region, at the opposite rod walls. These projections define a pivot
axis that lies perpendicular to the longitudinal parting of the
implant, and the setting element rests against the projections at a
distance from its connection with the tension piece. In this
manner, the pivot movement of the setting element is introduced
with little need for space, by exerting tensile forces on the
setting element. These forces are translated into an adjustment of
the two implant parts that takes place in the radial direction.
[0023] A stirrup is mounted on the handle, which can be pivoted
between a position that limits the axial adjustment path of the
threaded pin, and a position that eliminates this limitation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Other objects and features of the present invention will
become apparent from the following detailed description considered
in connection with the accompanying drawings. It is to be
understood, however, that the drawings are designed as an
illustration only and not as a definition of the limits of the
invention.
[0025] In the drawings, wherein similar reference characters denote
similar elements throughout the several views:
[0026] FIG. 1 shows a perspective representation of an implant
according to the invention;
[0027] FIG. 2 shows a side view of the implant from FIG. 1;
[0028] FIG. 3 shows a front view of the face of the implant from
FIG. 1;
[0029] FIG. 4 shows a top view of the implant from FIG. 1;
[0030] FIG. 5 shows a representation of the bottom of the implant
from FIG. 1;
[0031] FIG. 6 shows a representation of a distracted implant,
corresponding to FIG. 1;
[0032] FIG. 7 shows a representation of the implant from FIG. 6,
corresponding to FIG. 2;
[0033] FIG. 8 shows a representation of the implant from FIG. 6,
corresponding to FIG. 3;
[0034] FIG. 9 shows a representation of the implant from FIG. 6,
corresponding to FIG. 5;
[0035] FIG. 10 shows a perspective representation of the isolated
first implant part;
[0036] FIG. 11 shows a face view of the first implant part from
FIG. 10;
[0037] FIG. 12 shows a perspective representation of the isolated
second implant part;
[0038] FIG. 13 shows a face view of the second implant part from
FIG. 12;
[0039] FIG. 14 shows a top view of the second implant part from
FIG. 12;
[0040] FIG. 15 shows a perspective representation of the isolated
face plate;
[0041] FIG. 16 shows a side view of the face plate from FIG.
15;
[0042] FIG. 17 shows a schematic representation of the spinal
column with the spinal cord channel, as it presents itself to the
operator after having been exposed, during access from the
posterior direction;
[0043] FIG. 18 shows a representation corresponding to FIG. 17, to
illustrate the difficulties in creating appropriate space during
the operation;
[0044] FIG. 19 shows a side view of a distracted implant inserted
between two vertebrae;
[0045] FIG. 20 shows a top view of two implants according to the
invention placed on the cover plate of a vertebra;
[0046] FIG. 21 shows a representation corresponding to FIG. 19,
with the need for space for an implant known from the state of the
art being indicated;
[0047] FIG. 22 shows a representation corresponding to FIG. 20, in
which the upper implant according to the invention has been
replaced by an indication of the space required for an implant
known from the state of the art;
[0048] FIG. 23 shows a side view of an implant inserted into the
intervertebral space, in the non-distracted state, shown without a
stirrup;
[0049] FIG. 24 shows a representation corresponding to FIG. 23,
during distraction of the implant by means of the instrument;
[0050] FIG. 25 shows a top view of the implant and the instrument
from FIG. 23;
[0051] FIG. 26 shows a perspective representation of the implant
set onto the instrument;
[0052] FIG. 27 shows a representation corresponding to FIG. 26,
with the stirrup in the second position;
[0053] FIG. 28 shows a side view of the implant set onto the
instrument;
[0054] FIG. 29 shows a representation corresponding to FIG. 28, of
an isolated instrument;
[0055] FIG. 30 shows a side view of the individual parts of an
instrument taken apart;
[0056] FIG. 31 shows a perspective representation of the locking
screw; and
[0057] FIG. 32 shows a longitudinal cross-section through the
locking screw from FIG. 31.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0058] The drawing in FIG. 1 shows an implant 1, which is used for
intersomatic fusion of two adjacent vertebrae 2, if access to the
spinal column preferably takes place from the posterior direction.
Implant 1 consists of a first implant part 3 and a second implant
part 4, adjustable relative to the former, for the purpose of
distraction. First implant part 3 and second implant part 4 are
structured so that they supplement one another, in complementary
manner, in the non-distracted state, to form a pipe 5, having a
round cross-sectional shape, in other words a cylinder, that is
divided in the longitudinal direction. Guide surfaces 6 that extend
radially towards the inside, in the distraction direction, and rest
against one another, are formed on first implant part 3 and second
implant part 4. Guide surface 6 of first implant part 3 is formed
on its face 7, and guide surface 6 of second implant part 4 is
formed on a radially running slit 8 on the inside of a face plate
9, which is formed in two parts with second implant part 4. Slit 8
widens radially in the direction of first implant part 3; guide
surface 6 of first implant part 3 is formed on a guide wedge 10
that engages in slit 8, having wedge walls that run parallel to the
slit walls. Face plate 9 has an axially running guide groove 11
that is provided for interaction with a guide tab 12 that is formed
on second implant part 4. Guide wedge 10 is structured, in the
circumference direction, as a ring open on one side, which
surrounds guide tab 12 with ring opening 13 in the non-distracted
state.
[0059] Implant 1 furthermore possesses way for fixing the relative
position of first implant part 3 and second implant part 4 in
place, which comprises an axially running threaded bore 14 formed
in face plate 9, on the side that faces inward, and a ring eye 15
formed on second implant part 4, whereby ring eye 15 serves to hold
a locking screw 16 that engages in threaded bore 14. This locking
screw 16 is accessible through an implant opening 17, which is
present on a side of implant 1 that lies opposite face 7.
[0060] An alternative, not shown in the drawing, uses bone cement
as the means for fixation, which is introduced between first
implant part 3 and second implant part 4, and fills out and
reinforces implant part 1 after it hardens, as a solid core. A
plurality of guide grooves 18 is formed in implant opening 17, two
of which run along the longitudinal parting between first implant
part 3 and second implant part 4, and serve to interact with an
instrument 19 which is shown in detail in FIGS. 23 to 30.
[0061] FIGS. 1 to 11 and, in particular, the comparison with the
implants known from the state of the art, in FIGS. 21 and 22, make
the compact construction form of implant 1 according to the
invention, with a short length in the axial direction, evident.
This results in a varied possibility of use of implant 1, not only
from a dorsal or transabdominal direction, but also percutaneously,
from a further lateral direction, or with minimal invasiveness,
from a ventral direction. The use of implant 1 in pairs as shown in
FIG. 20 is preferred, but not necessary, since the ability of
implant 1 to withstand stress is so great that if the indication
and access are present, a single implant can be used.
[0062] Instrument 19 has a hollow rod 21 connected with a handle
20, which rod possesses a pivotable setting element 22 at its
front, free end, which element has two pins 23 for insertion into
the two guide grooves 18 assigned to the longitudinal parting. A
sleeve 24 is connected with a pivoting lever 25 on hollow rod 21,
which lever serves to activate a tension piece 26 that engages on
setting element 22, for pivoting. Furthermore, a hollow screwdriver
27 is arranged in hollow rod 21, through which screwdriver a
threaded pin 28 to be screwed into the threaded bore 29 of the
screw head of locking screw 16 passes. A rod thread 30 is formed on
the back end of hollow rod 21, with a threaded ring 31 arranged on
it, to limit the setting path of sleeve 24. The tension piece 26
engages at the top end of setting element 22, whereby projections
32 are formed on hollow rod 21, in the front region, at the
opposite rod walls, which projections define a pivot axis that lies
perpendicular to the longitudinal parting of the implant 1. Setting
element 22 rests against the projections at a distance from its
connection with the tension piece 26. A stirrup 33 is mounted on
handle 20, which can be pivoted between a position that limits the
axial adjustment path of the threaded pin, and a position that
eliminates this limitation.
[0063] Accordingly, while only a few embodiments of the present
invention have been shown and described, it is obvious that many
changes and modifications may be made thereunto without departing
from the spirit and scope of the invention.
* * * * *