U.S. patent application number 11/449860 was filed with the patent office on 2007-02-22 for devices and method for widening bone cavities.
This patent application is currently assigned to SINTEA BIOTECH S.p.A.. Invention is credited to Paolo Guerra, Domenico Prestamburgo, Giuseppe Sala, Michele Surace.
Application Number | 20070043373 11/449860 |
Document ID | / |
Family ID | 43533390 |
Filed Date | 2007-02-22 |
United States Patent
Application |
20070043373 |
Kind Code |
A1 |
Sala; Giuseppe ; et
al. |
February 22, 2007 |
Devices and method for widening bone cavities
Abstract
An widening device for bone cavities extends from a proximal end
to a distal end along an extension axis, said distal end having an
elastically deformable element suitable to pass from a relaxed
configuration for placing the distal end within an osteal body to a
deformed configuration for forming a cavity within said osteal
body. The elastically deformable element permits to create a bone
cavity in a regular and uniform way.
Inventors: |
Sala; Giuseppe; (Milano,
IT) ; Guerra; Paolo; (Milano, IT) ;
Prestamburgo; Domenico; (Varese, IT) ; Surace;
Michele; (Milano, IT) |
Correspondence
Address: |
HOGAN & HARTSON LLP;IP GROUP, COLUMBIA SQUARE
555 THIRTEENTH STREET, N.W.
WASHINGTON
DC
20004
US
|
Assignee: |
SINTEA BIOTECH S.p.A.
Giuseppe Sala
|
Family ID: |
43533390 |
Appl. No.: |
11/449860 |
Filed: |
June 9, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10502717 |
Jul 29, 2004 |
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PCT/IT04/00289 |
May 19, 2004 |
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11449860 |
Jun 9, 2006 |
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Current U.S.
Class: |
606/80 |
Current CPC
Class: |
A61B 2017/00867
20130101; A61B 17/8811 20130101; A61B 17/7098 20130101; A61B
17/8822 20130101; A61B 17/8858 20130101; A61B 2017/3445 20130101;
A61B 2017/0256 20130101; A61B 2090/036 20160201 |
Class at
Publication: |
606/080 |
International
Class: |
A61B 17/00 20060101
A61B017/00 |
Claims
1. Widening device for bone cavities extending from a proximal end
to a distal end along an extension axis, said distal end comprising
an elastically deformable element, suitable to pass from a relaxed
configuration for the positioning of the distal end within an
osteal body to a deformed configuration to form a cavity within
said osteal body, said elastically deformable element comprises at
least one tab suitable for widening a bone cavity by passing from a
relaxed configuration to a deformed configuration, wherein said
elastically deformable element extends from a first collar to a
second collar so that while said first and second collars approach
to each other along said extension axis, said at least one tab
bends in order to widen said internal cavity of the osteal
body.
2. Widening device according to claim 1, wherein said at least one
tab has, along its longitudinal extension, a thickness, as measured
relative to a radial direction incident to said extension axis and
contained in perpendicular plane to said extension axis, variable
along the extension axis such as to vary the stiffness of at least
one tab along the extension thereof.
3. Widening device according to claim 2, wherein said tab comprises
a central portion and two side portions relative to said extension
axis, opposite to said central portion, at least one of said side
portions having a radial thickness other than the radial thickness
of the central portion.
4. Widening device according to claim 3, wherein at least one tab
comprises a central portion having a radial thickness decreasing
towards the side portions.
5. Widening device according to claim 1, comprising a plurality of
tabs separated from one another by means of grooves.
6. Widening device according to claim 5, wherein said grooves
comprise slots at axial ends of the tabs.
7. Widening device according to claim 1, wherein said tabs are
arranged in an axial-symmetrical manner relative to said extension
axis.
8. Widening device according to claim 1, wherein said tabs are
arranged in an asymmetrical manner relative to said extension
axis.
9. Widening device according to claim 1, wherein a sheath suitable
to cover said tabs is mechanically associated to said elastically
deformable portion.
10. Widening device according to claim 9, wherein said sheath, in a
relaxed configuration, is at least partially separated from said
tabs.
11. Widening device according to claim 9, wherein said sheath has a
radial thickness varying along the extension axis.
12. Widening device according to claim 1 or 2, wherein the
elastically deformable element comprises at least one tab having a
prevalent extension along a median line, between a first collar and
a second collar, said median line extending so that a line, which
is parallel to extension axis and which passes through an
intersection point between the tab and the first collar, does not
pass through an intersection point between the tab and the second
collar.
13. Widening device according to claim 1 or 2, wherein said
elastically deformable element comprises at least one tab having a
predefined extension along a median line, said median line
extending along a helicoidal path with respect to said extension
axis.
14. Widening device according to claim 13, wherein said median line
extends according to a helix angle, said helix angle being defined
between a line perpendicular to a line parallel to extension axis
and passing through said median axis, and said median axis.
15. Widening device according to claim 14, wherein said helix angle
is comprised between 60 and 85 degrees.
16. Widening device according to claim 15, wherein said helix angle
is equal to 80 degrees.
17. Widening device according to claim 14, wherein said helix angle
is constant, along the extension of the tab.
18. Widening device according to claim 14, wherein the helix angle
is variable along the extension of the tab.
19. Widening device according to claim 18, wherein the helix angle
is greater near first and second collars which delimit axially the
elastically deformable element.
20. Widening device according claim 1, comprising a cannula
tubular, suitable for permit the passage of said elastically
deformable element, in a relaxed configuration, into said cannula,
for the insertion in said osteal body.
21. Widening device according to claim 20, wherein said cannula
comprises a gripping end suitable to be firmly made integral to the
osteal cortical area, and a connecting end comprising a bush
suitable to be connected to said widening device.
22. Widening device according to claim 21, wherein said bush is
suitable for being mechanically and selectively connected to a
widening device for bone cavities, to a cement injection device and
to a funnel for bone bits or bone substitute to be inserted within
said bone cavity.
23. Method for widening an osteal body comprising the steps of:
making a cannula having a gripping end and a connecting end
provided with a bush integral to the cortical area of an osteal
body, inserting in said cannula a widening device for bone cavities
mechanically connected by means of said bush, activating the
widening device to form a bone cavity, deactivating and disable the
widening device, inserting in said cannula a cement injection
device mechanically connected by means of said bush, injecting
cement in the bone cavity.
24. Method for widening an osteal body comprising the steps of:
making a cannula having a gripping end and a connecting end
provided with a bush integral to the cortical area of an osteal
body, inserting in said cannula a widening device mechanically
connected by means of said bush, activating the widening device to
create a bone cavity, deactivating and disabling the widening
device, inserting in said cannula a funnel mechanically connected
by means of said bush, inserting bone bits or bone substitute in
the bone cavity, through said funnel.
25. Method according to claim 23 or 24, wherein said widening
device is a widening device according to claim 1.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a widening device for bone
cavities, for example intervertebral cavities or cavities of the
tibial plate, the astragalus, or the wrist.
[0002] Particularly it relates to a widening device suitable to
restore collapsed bone structures, for example because of trauma or
aging, restoring at least partially the collapsed or degenerated
bone structure and creating a cavity to be stabilized, for example,
with a following injection of bone cement or another biocompatible
material. The present invention relates, for example, to a widening
device suitable for kyphoplasty operations.
[0003] The present invention further relates to an injection device
for bone cavities, for example intervertebral cavities or cavities
of the tibial plate, the astragalus, the wrist and the like. The
present invention relates, for example, to a device for kyphoplasty
suitable to inject liquid cement in a vertebral body for the
reconstruction of the same.
[0004] The present invention further relates to a method for
widening and filling bone cavities.
BACKGROUND OF THE INVENTION
[0005] Widening devices for use in intravertebral cavities are
known to be inserted in a relaxed configuration in a vertebral body
and then widened to an expanded configuration to restore the shape
of the vertebral body, thereby forming a suitable cavity therein
which is subsequently filled, for example with liquid cement, bone
bits or bone filler of various types.
[0006] The known wideners are not able to ensure a controlled
expansion inside the vertebral body, i.e. they are not suitable to
provide a volume-controlled tridimensional cavity having a desired
configuration.
[0007] The provision of a cavity having a well defined size is
indispensable for the reconstruction of a collapsed vertebral body
for example consequently to a trauma or bone degeneration.
[0008] The problem of the present invention is to provide a
widening device resolving the drawbacks mentioned with reference to
the prior art.
SUMMARY OF THE INVENTION
[0009] These drawbacks and limitations are resolved by a widening
device in accordance with claim 1.
[0010] Other embodiments of the widening device according to the
invention are described in the subsequent claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Further characteristics and the advantages of the present
invention will be better understood from the description below of
preferred and non-limiting exemplary embodiments thereof,
wherein:
[0012] FIG. 1 is a perspective view of a widening device according
to the present invention;
[0013] FIG. 2 is a cut-away view of the widening device from FIG.
1;
[0014] FIG. 3 is a perspective view of the widening device from
FIG. 1 with the addition of accessories;
[0015] FIG. 4A is a magnification of the detail IV from FIG. 1;
[0016] FIGS. 4B and 4C are magnifications of the detail IV from
FIG. 1, according to further embodiments of the present
invention;
[0017] FIG. 5A is a sectional view of the detail IV from FIG. 1
taken along line V-V from FIG. 4;
[0018] FIGS. 5B-5D show the detail from FIG. 5A comprising a sheath
according to different embodiments of the invention;
[0019] FIG. 6 is a sectional view of the device from FIG. 1;
[0020] FIG. 7 is a magnification of the detail VII from FIG. 6;
[0021] FIG. 8 is a magnification of the detail VIII from FIG.
6;
[0022] FIG. 9 is a sectional view of FIG. 3;
[0023] FIG. 10 is a magnification of the detail X from FIG. 9;
[0024] FIG. 11 is a magnification of the detail XI from FIG. 9;
[0025] FIG. 12 is a magnification of the detail XII from FIG.
9;
[0026] FIGS. 13A and 13B are perspective views of a detail of the
device from FIG. 1 in an expanded configuration, according to
further embodiments of the present invention;
[0027] FIGS. 13C and 13D are axonometric projections of the details
from FIGS. 13A and 13B respectively;
[0028] FIGS. 14A-14D are perspective views of a detail from FIG. 1
in a relaxed configuration and in expanded configurations according
to different embodiments, respectively;
[0029] FIGS. 15A-15D are front views of FIGS. 14A-14D,
respectively;
[0030] FIG. 16A-16D are insertion diagrams of widening devices in
collapsed osteal bodies, in a relaxed configuration;
[0031] FIGS. 17A-17D are insertion diagrams of the widening devices
of FIGS. 16A-16D in restored osteal bodies, in an expanded
configuration;
[0032] FIG. 18 is a perspective view of an injection device
according to the invention, in an open configuration of the
device;
[0033] FIG. 19 is a perspective view of the injection device from
FIG. 18, in a closed configuration of the device;
[0034] FIG. 20 is a side view of the injection device from FIG. 18
in an initial injection step configuration;
[0035] FIG. 21 is a side view of the injection device from FIG. 18
in a final injection step configuration;
[0036] FIG. 22 is a perspective view of the injection device from
FIG. 18 as being inserted in an osteal body, for example a
vertebral body, at the beginning of the injection step;
[0037] FIG. 23 is a perspective view of the injection device from
FIG. 18 as being inserted in an osteal body, for example a
vertebral body, at the end of the injection step;
[0038] FIG. 24 is a perspective view of an injection device
according to a further embodiment of the invention;
[0039] FIG. 25 is a cut-away sectional view of the device from FIG.
24;
[0040] FIG. 26 is a sectional view of the device from FIG. 24, at
the beginning of the injection step;
[0041] FIG. 27 is a sectional view of the device from FIG. 24, at
the end of the injection step;
[0042] FIG. 28 is a perspective view of the injection device from
FIG. 24 as being inserted in an osteal body, at the beginning of
the injection step;
[0043] FIG. 29 is a perspective view of the injection device from
FIG. 24 inserted inside an osteal body, for example a vertebral
body, at the end of the injection step;
[0044] FIG. 30 is a perspective view of a device for the insertion
either of bone bits or bone filler in an osteal body, for example a
vertebral body.
DETAILED DESCRIPTION OF THE INVENTION
[0045] The elements or element parts in common between the
embodiments described below will be indicated with the same
numerals.
[0046] With reference to the above figures, with 4 has been
generally indicated a widening device suitable to provide a cavity
within an osteal body, for example a vertebral body 6, a tibial
plate 6', an astragalus 6'', a wrist 6''' asnd the like.
[0047] By `widening device` it is intended a widening device
suitable for restore collapsed osteal structures, for example
because of trauma or aging, by restoring at least partially the
degenerated or collapsed osteal structure and by creating a cavity
to be stabilized, for example by subsequent injection of osteal
cement or other biocompatible material.
[0048] The widening device 4 has an elongate shape as a whole and
develops along an extension axis X, between a proximal end 8 and a
distal end 10.
[0049] Herewith below, by axial direction will be designated a
direction parallel to the extension axis X, and by radial direction
will be designated a perpendicular direction to the extension axis
X and incident thereto.
[0050] The widening device 4 comprises a cylindrical shank 12,
extending from the proximal end 8 to the distal end 10.
[0051] The shank 12 comprises a first through hole 13 arranged on
the side of the proximal end 8.
[0052] To the shank 12 there is associated a tube 14 externally and
coaxially thereto, relative to axis X, such as to at least
partially cover the shank 12. The tube 14 extends between a first
end 14', facing the proximal end 8, and a second end 14'', facing
the distal end 10.
[0053] The tube 14 comprises an aperture 16 having an axial
extension L, arranged on the side of first end 14'.
[0054] At the proximal end 8 the shank 12 is provided with a
threaded length 24 for a knob 28 to be associated thereto according
to a screw-nut type coupling.
[0055] To the shank 12 and tube 14 is further coaxially associated
a sleeve 32, arranged between the distal end 10 and the proximal
end 8.
[0056] The sleeve 32 comprises a pin 36 mechanically connecting the
sleeve 32 with the shank 12 and the tube 14 such as to rotatably
lock both of them, relative to the X axis.
[0057] The pin 36 has a smaller diameter than said extension L of
aperture 16.
[0058] Particularly, in an assembly configuration, said pin 36 is
inserted in the sleeve 32 such as to intercept the first hole 13 of
shank 12 and aperture 16 of tube 14. Furthermore, in an assembly
configuration, the second end 14'' of tube 14 comprises the distal
end of shank 12 therein.
[0059] The profile of end 14'' of tube 14 identifies a first strike
38.
[0060] Between the sleeve 32 and the knob 28 there is inserted a
spacer 40, coaxial with the shank 12, said spacer 40 at least
partially intercepting the threaded length 24.
[0061] Between the spacer 40 and the knob 28 there is inserted,
coaxially with the shank 12, a stop element 44, suitable to receive
the knob 28 in abutment. Preferably, the stop element 44 is
one-piece with the tube 14 at the first end 14'.
[0062] The spacer 40 and the tube 14 are suitable to axially slide
along the extension axis X relative to shank 12.
[0063] Particularly, the spacer 40 can axially slide relative to
shank 12 for a length being almost equal to the axial distance
between the end of spacer 40 facing the stop element 44 and the
stop element.
[0064] The tube 14 can axially slide relative to shank 12 to the
extent of the backlash present between the aperture 16 and the pin
36.
[0065] At the distal end 10, to the shank 12 there is associated a
cylindrical terminal 48 which, on the opposite side to the shank
12, comprises a second strike 52, of a substantially greater
diameter than the diameter of shank 12.
[0066] Preferably, the terminal 48 is removably associated to shank
12, such as by means of a threaded connection.
[0067] According to an embodiment, the terminal 48 comprises a
pivot suitable to be screwed to the free end of shank 12, and the
pivot head provides said first strike 38.
[0068] An elastically deformable element 56 is mounted along the
extension axis X, coaxially to the terminal 48.
[0069] The elastically deformable element 56 is cylindrical and
hollow as a whole and is suitable to be fitted on terminal 48.
[0070] Preferably, the elastically deformable element 56 comprises
a central body 57 with a diameter d, axially defined by a first and
second collar 58',58'' with a diameter D greater than the diameter
d of the central body 57.
[0071] The elastically deformable element 56 further comprises an
inserting portion 59, connected to first collar 58' and axially
extending from the opposite side to second collar 58''.
[0072] The inserting portion 59 is suitable to be inserted in the
inner diameter of tube 14 and extends such that, in an assembly
configuration and in the relaxed configuration, between the
inserting portion 59 and shank 12 an axial backlash G is
identified.
[0073] Preferably, the axial backlash G is almost equal to the
axial extension L of aperture 16. The axial distance between the
first and second collars 58',58'' is almost equal to the distance
between the first and second strikes 38,52; in other words, in a
relaxed configuration, the central body 57 is inserted with
substantially no backlash between both strikes 38,52.
[0074] In the relaxed configuration, the elastically deformable
element 56 is not subjected to axial loads and is substantially
parallel to the extension axis X.
[0075] Advantageously, relative to a perpendicular plane to the
extension axis X, the elastically deformable element 56 has a
variable thickness along said extension axis X; in other words, the
radial thickness of the elastically deformable element 56 varies
advantageously along a parallel direction to said extension axis
X.
[0076] The elastically deformable element 56 is preferably made of
a polymeric material, an elastomer, a rubber and the like. The
preferred materials to be used are characterized by a high modulus
of elasticity value, such as to ensure high distraction forces and
resistance to considerable loads, as well as characterized by a low
ratio of the modulus of elasticity and the yield stress, such as to
minimize the risk of yield due to great deformation.
[0077] Furthermore, metal, composite or polymeric materials, as
well as shape-memory, metal or polymeric materials can also be
used.
[0078] Preferably, the deformable element 56 comprises at least one
tab 60 which, in the relaxed or undeformed configurations, extends
substantially parallel to axis X.
[0079] According to a further embodiment, the elastically
deformable element 56 comprises at least one tab 60 having a
prevalent extension along a median line M, between a first collar
58' and a second collar 58'', said median line M extending so that
a line, which is parallel to axis X and which passes through an
intersection point between the tab 60 and the first collar 58',
does not pass through an intersection point between the tab and the
second collar 58''.
[0080] According to a preferred embodiment, the elastically
deformable element 56 comprises at least one tab 60 which, in a
relaxed or undeformed configuration, extends along a helicoidal
path with respect to said axis X. The tab 60 extends along a
helicoidal path with respect to axis X, according to a helix angle
a. In other words, the elastically deformable element 56 comprises
at least one tab 60 having a preferred extension along a median
line or axis M, said median axis M having a helicoidal extension
with respect to said axis X.
[0081] Said median axis M extends according to a helix angle
.alpha., said angle being defined between a line perpendicular to a
line parallel to axis X and passing through said median axis M, and
said median axis M.
[0082] By median axis M of the tab it is intended a line passing
through a median line of the tab which is also a curvilinear
symmetry axis for the tab.
[0083] The helix angle .alpha. is preferably comprised between 60
and 85 degrees, and most preferably is equal to 80 degrees.
According to an embodiment, said helix angle a is constant, along
the extension of the tab 60. According to another embodiment, the
helix angle .alpha. is variable along the extension of the tab 60;
in other words the tab 60, along its extension, wraps around axis X
according to a variable helix angle .alpha..
[0084] Preferably, the helix angle .alpha. is greater near first
and second collars 58',58''.
[0085] According to an embodiment, said tab 60 along its helicoidal
extension presents a thickness, being measured with respect to a
radial direction incident with said axis X and contained in a plane
perpendicular to said axis X, said thickness being variable along
the helicoidal extension of the tab 60.
[0086] The at least one tab 60 is formed in the elastically
deformed element 56 by means of longitudinal grooves 64 if the tab
has a longitudinal extension parallel to axis X; otherwise the tab
60 is formed in the elastically deformed element 56 by means of
helicoidal grooves 64' if the tab has a helicoidal extension with
respect to axis X. Said helicoidal grooves 64' may be obtained by a
CNC machine having a working head which moves along a helicoidal
direction so as to cut away material from a solid tubular element
and to obtain said grooves.
[0087] Advantageously, at ends facing the first and second collars
58',58'', respectively, the grooves 64,64' end with slots 68, for
example of a circular shape.
[0088] According to an embodiment, each tab 60 has a central
portion 72 and two side portions 76', 76'' being axially arranged
on opposite sides to the central portion 72.
[0089] The side portions 76', 76'' are in turn connected to the
respective collars 58',58'' through attachment portions 80',
80''.
[0090] According to an embodiment, the tabs 60 have a midplane S
perpendicular to the extension axis X and positioned in the middle
of central portion 72; in other words, the side portions 76', 76''
and the attachment portions 80', 80'' have the same axial
extension. According to further embodiments, the side portions
76',76'' and/or the attachment portions 80',80'' have different
axial extensions.
[0091] According to further embodiments, the tabs 60 have only one
side portion 76' or 76'' and do not exhibit the midplane S, i.e.
the central portion is directly connected to the respective collar
58' or 58''.
[0092] Furthermore, the central body 57 can have an outer diameter
varying along the longitudinal extension of the same.
[0093] Such as for example illustrated in FIG. 5, each tab 60
advantageously has radial thicknesses varying along the extension
axis X. This variation in the thicknesses can be discrete, such
that the elastically deformable element 56 has marked variations in
the thickness for example at the interface areas between the
central portion 72 and the side portions 76',76'' or between the
side portions 76',76'' and the attachment portions 80',80''.
According to a further embodiment this variation in the thicknesses
is gradual and continuous, i.e. said interface areas between the
central portion 72 and the side portions 76',76'' or between the
side portions 76',76'' and the attachment portions 80',80'' are
suitably linked up to one another in the thicknesses thereof.
[0094] For example, at the central portion 72, the greater
thickness of each tab 60 gradually decreases towards the attachment
portions 80',80''.
[0095] Furthermore, each tab 60 has, relative to a perpendicular
plane to the extension axis X, a section shaped like a ring sector,
having a minor arch 84 facing the axis X and a major arch 88 facing
outwardly.
[0096] Preferably, the elastically deformable element 56 has a
plurality of tabs 60; according to some preferred embodiments, such
as illustrated for example in FIGS. 14A-14D, the elastically
deformable element 56 has three or four tabs symmetrically or
asymmetrically arranged relative to the extension axis X.
[0097] According to an advantageous embodiment, said elastically
deformable element 56 comprises a sheath 92 extending between the
attachment portions 80',80'' such as to wrap or cover said tabs
60.
[0098] In the relaxed configuration of the elastically deformable
element 56, the sheath 92 has a substantially axial-symmetrical
extension coaxial with the extension axis X. According to an
embodiment, the sheath 92 has a cylindrical extension, with a
substantially constant diameter, such as to at least partially
adhere to tabs 60 also in a relaxed configuration. According to a
further embodiment, the sheath 92 has a cylindrical extension with
a varying diameter such as to adhere, in a relaxed configuration,
to the elastically deformable element 56 at the collars 58',58''.
According to a further embodiment, the sheath 92 has an ellipsoidal
extension as a whole in a relaxed configuration, having a varying
diameter along the extension of said axis X, for example such as to
come in contact with tabs 60 at the collars 58',58'' and not at the
central portion 72 of tabs 60. Furthermore, the sheath 92 can be
double-lobe shaped or however have a varying section along the
longitudinal extension of sheath 92, said section being taken on a
perpendicular plane to axis X.
[0099] According to an embodiment the sheath 92 has a constant
thickness along the extension thereof. According to a further
embodiment, such as illustrated in FIG. 5D, the sheath 92 has a
varying thickness along the extension thereof; for example the
sheath 92 has a thickening 93 at the connecting portions to the
elastically deformable element 56 and a thinning 94 in a portion
comprised between said connecting portions and facing for example
the central body 57 of tabs 60.
[0100] Preferably, the sheath 92 is made of an elastic material
such as a polymer, an elastomer, a rubber, and is suitable to be
matched to the tabs 60 in the deformed configuration.
[0101] According to an embodiment, the sheath 92 is associated to
the elastically deformable element 56 by glueing at the first and
second collars 58',58''.
[0102] According to an advantageous embodiment, the widening device
4 comprises a cylindrical cannula 96 suitable to cover the tube 14
in the length comprised between the distal end 10 and sleeve
32.
[0103] Preferably, said cannula 96 is provided with a threaded bush
100 at a connecting end 106 facing the sleeve 32; the bush 100 acts
as an adjusting sleeve to tailor the insertion depth of the
widening device 4 inside the osteal body 6,6',6'',6'''.
[0104] Advantageously, said cannula 96 is provided with a gripping
end 104, suitable to be locked on the cortex of an osteal body 6,
like a vertebral body 6, a tibial plate 6', an astragalus 6'' or a
wrist 6''', such as to form a guide for the widening device 4 to be
inserted therein, and also for the insertion of a probe to first
inspect the interior of the osteal body 6, 6',6'',6'''.
Advantageously, the cannula 96 allows the use, i.e. the coupling
with endoscopic, microscopic systems and for biopsy sampling.
[0105] Furthermore, the cannula 96 is advantageously suitable to at
least partially house a cement injection device 112 to fill the
osteal cavity with liquid cement.
[0106] The injection device 112 comprises a grip element 116
suitable to allow the grip by a user and having a pusher 118 for
example of a cylindrical shape, integrally connected to the grip
element 116. In an assembly configuration of the injection device
112 on the cannula 96, the pusher 118 is coaxial to the extension
axis X. The grip element 116 further comprises at least one seat
120.
[0107] On the grip element 116 there is hinged a lid 122, suitable
to rotate from an open position, such as illustrated for example in
FIG. 18, to a closed position such as illustrated for example in
FIG. 19.
[0108] The lid 122 further comprises a window 123 and a
corresponding graduated scale suitable to measure the relative
translation between a control element 126 and the grip element 116.
At an end facing the hinging end of the grip element 116 on lid
122, the lid 122 ends with a stop 124 having a notch 125.
[0109] To said grip element 116 there is associated the control
element 126 mechanically connected to a plate 130, of a circular
shape having a second hole 134.
[0110] The control element 126 and the grip element 116 in a closed
configuration, where the stop 125 and the plate 130 directly face
each other, identify a chamber 135 suitable to house a cement
cartridge 136 to be injected.
[0111] Preferably, the control element 126 comprises at least one
guide 138 suitable to be at least partially housed within said seat
120, such that the motion of the control element 126 relative to
the grip element 116 is guided substantially along a stroke T
according to a direction parallel to axis X.
[0112] A cylindrical needle 140, hollow and suitable to be housed
within the cannula 96, is mechanically associated to the plate 130
through said second hole 134 such that an injection end 144 of
needle 140 is fluidically connected to chamber 135.
[0113] A further embodiment of an injection device 112' will be now
described, such as illustrated for example in FIGS. 24-29, wherein
the elements or parts in common with the embodiment illustrated
above will be indicated with the same numeral provided with
primes.
[0114] The injection device 112' has a cartridge configuration as a
whole, of main extension P. The injection device 112' comprises a
hollow grip element 116' of a cylindrical shape suitable to be held
by a user. At an inner side wall 150 the grip element 112'
comprises a first threading 152 with pitch M'. Opposite to the
first threading 152, relative to the main extension P, the grip
element 112' comprises a flange 154 having longitudinal guides 156
arranged parallel to the main extension P.
[0115] A first cylindrical and hollow ring nut 158 is suitable to
mesh with said first threading 152 at a first control portion 160
such as to be coaxially mounted to the grip element 116' and
internally thereto.
[0116] The first ring nut 158, opposite to the first control
portion 160, comprises a second control portion 162 provided at an
inner part, i.e. towards the extension axis P, with an inner
threading of pitch M'', other than said pitch M'. Advantageously,
pitch M'' of second threading 164 is greater than pitch M' of first
threading 152; preferably pitch M'' is about twice the pitch
M'.
[0117] The first ring nut 158, opposite to the second threading
164, comprises a neck 166 provided with a notch 168. At the neck
166, to the first ring nut 158 there is associated a control
element 126' preferably in the form of a hollow knob. Particularly,
the control element 126' is removably fastened to the neck 166,
through a bayonet-type arrangement, by means of at least one stake
170 suitable to be locked within said notch 168. Between the
control element 126' and the neck 166 there is interposed a barrel
172 for the at least one stake 170 to be mounted thereto; the
barrel 172 is provided with a spring 173 such as to force said
stake against the corresponding notch 168.
[0118] The control element 126' comprises a bell 174 suitable to
house said barrel 172 and suitable to be at least partially
inserted in the first ring nut 158 from the neck 166. The bell 174
axially ends with a stop surface 175, such as of a disc-shape
type.
[0119] In an assembly configuration, the control element 126', the
barrel 172 and the first ring nut 158 are preferably rotatably
integral to one another.
[0120] To the grip element 116', opposite to the first threading
152, there is associated a second ring nut 176 having an outwardly
threaded portion 178 suitable to mesh with the second threading
164. Opposite to the outwardly threaded portion 178, along
extension P, the second ring nut 176 comprises at least one pivot
180 suitable to be housed within said longitudinal guides 156, such
as to longitudinally slide therealong; furthermore, the second ring
nut 176 comprises an abutment surface 182 of a circular ring shape.
To the second ring nut 176 is further associated a cylindrical plug
184, arranged at the opposite end of the control element 126', and
preferably comprising a threaded ring 186 suitable to be screwed on
the threaded bush 100.
[0121] In an assembly configuration, the first ring nut 158 and the
second ring nut 176 are coaxially and partially mounted within the
grip element 116' such as to define a substantially cylindrical
chamber 135'.
[0122] The injection device 112' is suitable to contain within said
chamber 135' a substantially cylindrical syringe 188 comprising a
syringe body 190 enclosing a cement cartridge 136' to be injected,
a pusher 118' being associated thereto, which is suitable to
compress said cement cartridge 136'. The cement cartridge 136',
opposite to the pusher 118', is fluidically connected to a needle
140' and according to an embodiment, the syringe body 190 is
one-piece with the needle 140'.
[0123] As illustrated for example in FIG. 30, the cannula 96 is
further suitable to be connected to a funnel 200, at the proximal
end. Said funnel 200 is suitable to allow bone bits, i.e. bone
fragments, such as taken from the iliac crest or generally bone
substitute to be inserted therein.
[0124] Furthermore, the cannula 96 allows a rammer, i.e. an
elongate cylindrical body having a rounded end, suitable to compact
the bone bits or the bone substitute inserted therein, to be
inserted within the cavity of a vertebral body 6, tibial plate 6',
astragalus 6'', wrist 6''', by means of the cannula 96.
[0125] The operation of the widening device according to the
invention will be now described.
[0126] At first, the cortical and sponge tissues of the osteal body
6, like for example a vertebral body 6, a tibial plate 6', an
astragalus 6'', a wrist 6''', are pierced with a punch such as to
enable the cannula 96 to be firmly fixed to the osteal body
6,6',6'',6'''.
[0127] An endoscope may be firstly inserted in said cannula 96 to
inspect the interior of the osteal body 6,6',6'',6'''.
[0128] The cannula 96 can then house the widening device 4
therein.
[0129] In order to properly tailor the insertion depth of the
widening device 4 the above threaded bush 100 can be used to act as
the adjustment sleeve.
[0130] The elastically deformable element can be then expanded
56.
[0131] Particularly, the knob 28 can be rotated on the threaded
length 24 of shank 12, by holding the sleeve 32 at the same time,
such as to cause the shank 12 to be tensioned, which is rotatably
locked by the pin 36 of sleeve 32.
[0132] The shank 12 translatably drags the terminal 48 and the
elastically deformable element 56 which in turn pushes the first
strike 38 of tube 14. The tube 14 translates at first towards the
proximal end until completely recovering the backlash between the
pin 36 and the aperture 16.
[0133] The rotation of knob 28 generates the compression of the
elastically deformable element 56 between the first and second
strike 38,52. Following said compression the tabs 60, subjected to
a compression load, tend to inflect outwardly, thereby taking an
expanded or deflected configuration, such as arch-shaped.
[0134] While being bent, the tabs 60 can be advantageously
encircled by the sheath 92 filling the gaps or grooves 64 between
the tabs 60.
[0135] Once the desired size has been obtained for the osteal
cavity the widening device 4 can be disabled.
[0136] By rotating the knob 28 to the opposite direction the
elastically deformable element 56 is unloaded and tends to return
in the undeformed or relaxed configuration due to the elasticity of
tabs 60. The sheath 92 until being stressed by the action of the
tabs 60, cooperates to the passage from the deformed configuration
to the undeformed configuration.
[0137] Therefore, the passage from the deformed configuration to
the undeformed or relaxed configuration does not take place by
applying another external force, but by removing the initial
deformation force, i.e. by unloading the shank 12 and the
elastically deformable element 56 accordingly.
[0138] The axial backlash between the pin 36 and the aperture 16 on
tube 14 ensures that, once the knob 28 has been completely
unscrewed, the tabs 60 can completely stretch without having
compression loaded residues.
[0139] On the contrary, there would be the risk for the elastically
deformable element 56 to be locked inside the osteal body
6,6',6'',6''' or inside the cannula 96.
[0140] The widening device 4 can be then extracted and the
injection device 112,112' or the funnel 200 can be subsequently
inserted to fill the osteal cavity with liquid cement or bone bits,
respectively.
[0141] The operation of the injection device 112 according to an
embodiment will be now described.
[0142] Particularly, once the cartridge 136 has been inserted in
chamber 135, and the lid 122 has been closed, one holds the grip
element 116 and presses the control element 126, such as to
approach i.e. move the control element 126 backward towards the
grip element 116. The cartridge 136 is compressed between the plate
130 translatably dragged by the grip element 116 and the pusher
118. The cement contained in the cartridge 136 tends to flow inside
the needle 140 and to exit through the injection end 144 of the
same.
[0143] During the backward motion of the control element 126, the
same drags the needle 140 which tends to move backwards while the
cement is being injected. Consequently, the injection end 144 moves
backward during the injection step, by a stroke T equal to the
translation stroke of the control element 126. The amount of cement
to be injected can be controlled by directly reading the
translation of needle 140 with the aid of a graduated scale on
window 123 of lid 122.
[0144] The operation of the injection device 112' will be now
described according to a further embodiment of the invention.
[0145] To assemble the syringe 188 within the injection device
112', the control element 126' is first extracted by disengaging
the stake 170 from notch 168 of neck 166, and the barrel 172 is
removed to gain access to chamber 135'.
[0146] Thereafter, the syringe 188 provided with needle 140' is
inserted in the chamber 135' such as to bring the cement cartridge
136' in abutment against the abutment surface 182 of second ring
nut 176. The control element 126' is then reassembled such as to
bring the end surface 175 of bell 174 in contact with the pusher
118'. In other words, following the assembly of syringe 188 to the
injection device 112', syringe 188 is housed coaxially to the
injection device 112' as well as axially constrained from opposite
sides, i.e. between the control element 126' and the second ring
nut 176.
[0147] Particularly, following the assembly, the pusher 118' of
syringe 188 is in abutment against the stop surface 175 of the
control element 126', such as to prevent the pusher 118' to move
backwards according to a backward direction r; whereas the syringe
body 190 abuts against the abutment surface 182 of second ring nut
176, such that the syringe body 190 cannot be moved according to a
forward motion relative to a forward direction f opposite to said
backward direction r.
[0148] The outwardly threaded portion 178 is first engaged on bush
100 such as to house the needle 140' of injection device 112'
within the cannula 96 and form a fluidical connection between the
cement cartridge 136, the injection end 144 and the cavity of the
osteal body 6,6',6'',6'''.
[0149] To perform the injection, one holds the grip element 116'
and rotates the control element 126' such as to rotatably drag the
first ring nut 158; particularly the first ring nut 158, by
screwing on the grip element 116', moves forward, i.e. it
translates towards needle 140', according to the forward direction
f. The second ring nut 176 meshes in turn with the grip element
116' and, since it cannot rotate relative to the grip element 116'
due to the coupling between pivots 180 and longitudinal guides 156
of flange 154, it translates away from needle 140', according to
the backward direction r opposite to said forward direction f.
Therefore, following the rotation of the control element 126', the
first and second ring nuts 158,176 translate along extension P in
opposite directions f,r thus approaching each other
respectively.
[0150] The abutment surface 182 of second ring nut 176 when being
translating urges the cement cartridge 136 which is compressed
between the syringe body 190 in abutment against the abutment
surface 182 and pusher 118', which cannot move backward according
to backward direction r due to the stop surface 175. The syringe
body 190 moves backward together with the abutment surface 182 of
second ring nut 176 and drags the needle 140' in its backward
motion along the backward direction r. Consequently, following the
rotation of the control element 126', needle 140', and particularly
the injection end 144 of needle 140', moves backward by a stroke T
according to the backward direction r.
[0151] Furthermore, while screwing and moving forward within the
grip element 116', the first ring nut 158 translatably drags the
control element 126' towards the second ring nut 176. Therefore,
the stop surface 175 of the control element 126' urges in turn the
pusher 118' of syringe 188 according to the forward direction f and
further compresses the cement cartridge 136'. Following this
compression the cement tends to exit through the injection end 144
of needle 140' and from the latter to the inside of the osteal
cavity. The pivots 180 slide in the longitudinal guides 156 and by
being visible from the outside of the injection device 112', also
provide a visual indication of the feeding state of the injection,
i.e. the amount of cement being injected. Preferably, near the
longitudinal guides 156, there is provided, for example, a
graduated scale to give an indication of the amount of cement being
injected.
[0152] Advantageously, by dismounting the control element 126'
during any cement injection step, the cement capsule 136' stops
being subjected to compression and the cement flow through needle
140' is stopped.
[0153] As may be appreciated from what has been stated above, the
widening device allows to overcome the drawbacks of the prior art
widening devices.
[0154] Particularly, the widening device according to the invention
allows to provide a cavity within an osteal body, such a vertebral
body, an astragalus, a tibial plate, a wrist, in a controlled
manner, i.e. by providing predetermined expansion configurations
which can be adjusted according to different types of osteal bodies
and different surgical indications.
[0155] In other words, the widening device ensures an active
expansion, by generating a cavity of a defined shape without being
subjected to deformations by the bone tissue of the osteal body,
the mechanical characteristics of which are typically not isotropic
and omogeneous.
[0156] The covering sheath, by filling the grooves comprised
between the tabs, ensures continuity to the deformable element
thereby preventing the individual tabs from getting entangled
within the osteal body tissue, thereby allowing the deformed
configuration to return to the relaxed configuration.
[0157] Advantageously, the presence of the sheath covering the tabs
prevents any inclusion of bone material within the elastically
deformable element, which case may hinder the tab closing motion,
i.e. their return to the undeformed configuration.
[0158] Thanks to the helicoidal arrangement of tabs, the device has
a solidity of the created volume, it is to say the volume of the
device in an expanded configuration, which is greater than the
arrangement with longitudinal tabs. By solidity it is intended the
ratio between solid and void zones, it is to say between the zone
comprising the tabs, which contribute to the widening of the
cavity, and the interstices among the tabs which do not exerte any
widening action of the osteal tissue. A greater solidity of the
deformable element grants a controlled expansion, in spite of the
anisotropy of the spongeous tissue in the cavity of the osteal
body. A high solidity avoids the event of gripping of the tabs in
the spongeous tissue and does not require the use of sheaths or
membranes, suitable for fill said voids or interstices among
tabs.
[0159] The particular varying-thickness configuration along the
tabs both with longitudinal extension and with elicoidal extension,
allows to provide greater thicknesses in the tab areas subjected to
greater loads and lower thicknesses in the areas where, following
the deformation, great bending is desired without yielding the
material. In fact, any yield may hinder the elastic return of the
deformable portion from the deformed configuration to the relaxed
configuration.
[0160] In fact, the return from the deformed configuration to the
relaxed configuration takes place due to the elastic return of the
material following the removal of the axial force which had caused
the deformation, i.e. without applying another external force.
[0161] This elastic return is favoured by the elastic action
provided by the sheath which tends to cause both tabs to approach
each other, thereby bringing them back to the undeformed
configuration.
[0162] By providing the deformable element as one-piece, the
resistance of the tabs to high work load is ensured. Particularly,
the presence of the slots to the tab ends prevents the risk that
any crack may propagate.
[0163] The tabs are therefore beams fitted to the ends, which when
subjected to compression, instabilize and inflect outwardly, i.e.
away from the extension X axis.
[0164] This arrangement provides a particular stiffness to the
deformable portion and allows to vary the stiffness of the tabs by
acting on the variation of thicknesses.
[0165] The backward motion of the needle during the cement
injection ensures an optimum filling of the osteal cavity because
the injection end moves gradually and automatically backward as the
cavity is being filled. A uniform and omogeneous distribution of
the cement being injected in the bone cavity is thereby ensured.
Furthermore, due to the backward motion of the needle,
overpressures in the osteal body are prevented which may give
origin to leakages of cement dangerous for the spinal marrow if,
for example, the osteal body is a vertebral body.
[0166] The configuration of the cannula provided with a tailored
bush allows to associate different devices to this cannula for an
operation of widening and restoring of an osteal cavity, such as a
kyphoplasty operation, after only one access port has been made in
the osteal cortical area and only one cannula has been inserted as
the guide member. The bush allows to change the axial position of
each of the devices being inserted, particularly the insertion
depth of the distal end of the widening device and the needle
injection end.
[0167] Those skilled in the art, aiming at satisfying contingent
and specific requirements, will be able to carry out a number of
modifications and variants to the above widening devices, which are
all contemplated within the scope of the invention such as defined
by the claims below.
* * * * *