U.S. patent application number 10/039892 was filed with the patent office on 2004-10-28 for high pressure applicator.
Invention is credited to Preissman, Howard E..
Application Number | 20040215202 10/039892 |
Document ID | / |
Family ID | 21981981 |
Filed Date | 2004-10-28 |
United States Patent
Application |
20040215202 |
Kind Code |
A1 |
Preissman, Howard E. |
October 28, 2004 |
High pressure applicator
Abstract
A pressure applicator for applying pressure to a flowable
implant material, e.g., PMMA. A pressure applicator or driver
includes a pair of columns which are engageable with one another,
preferably by threads to generate a driving pressure. A handle is
provided for the operator to grasp and steady the device as he
turns the handle to apply pressure to the implantable material
within the applicator. A luer-lock or other connecting device is
provided for attaching the applicator to a cannula (or a connecting
conduit that in turns connects with a cannula) that will deliver
the implant material to the desired site. Pressures of about
1000-3000 psi may be generated by this device.
Inventors: |
Preissman, Howard E.; (San
Jose, CA) |
Correspondence
Address: |
BOZICEVIC, FIELD & FRANCIS LLP
200 MIDDLEFIELD RD
SUITE 200
MENLO PARK
CA
94025
US
|
Family ID: |
21981981 |
Appl. No.: |
10/039892 |
Filed: |
October 26, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10039892 |
Oct 26, 2001 |
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09409934 |
Sep 30, 1999 |
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6383190 |
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09409934 |
Sep 30, 1999 |
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09053108 |
Apr 1, 1998 |
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Current U.S.
Class: |
606/94 |
Current CPC
Class: |
A61F 2/4603 20130101;
A61F 2002/4677 20130101; A61B 17/8822 20130101; A61B 17/8833
20130101; A61F 2/4601 20130101; A61F 2/44 20130101; A61B 17/8816
20130101; A61B 17/8819 20130101 |
Class at
Publication: |
606/094 |
International
Class: |
A61B 017/58 |
Claims
1. A high pressure applicator for driving the delivery of a
flowable tissue implant material, comprising: a first column having
an inner wall, an outer wall, a first end and a second end having
an orifice for delivering implant material therethrough; a second
column, said second column being drivable with respect to said
first column to generate a pressure within said first column; and a
handle attached to said first column and radially extending
therefrom to provide a user a mechanical advantage upon grasping
said handle.
2. The high pressure applicator of claim 1, further comprising at
least one sealing element interfacing with said inner wall of said
first column, said at least one sealing element providing for or
enhancing generation of said pressure.
3. The high pressure applicator of claim 1, wherein said second
column comprises a wall which is drivably engageable with one of
said inner and outer walls.
4. The high pressure applicator of claim 1, further comprising a
handle integrally formed with or affixed to and extending radially
from said second column to provide the user a mechanical advantage
upon grasping said handle.
5. The high pressure applicator of claim 1, further comprising
threading on said outer wall of said first column, wherein said
second column is substantially hollow and comprises an open first
end, a closed second end and threading on an inner wall thereof,
said threading on said second column being engageable with said
threading on said first column.
6. The high pressure applicator of claim 5, wherein said second
column further comprises an extension integrally formed with or
affixed to said second column and having an end portion extending
from said open end of said second column, said extension adapted to
be inserted through said open end of said first column and form a
substantial pressure seal with said inner wall.
7. The high pressure applicator of claim 6, further comprising at
least one sealing element mounted to said end portion of said
extension and adapted to form a pressure seal with said inner wall
thereby forming a pressure seal between said first and second
columns.
8. The high pressure applicator of claim 7, wherein said at least
one sealing element comprises an O-ring.
9. The high pressure applicator of claim 5, further comprising a
plunger element adapted to be inserted within said first and second
columns, said plunger element having a first end portion and a
second end portion.
10. The high pressure applicator of claim 9, wherein said first end
portion is adapted and configured to closely fit within said inner
wall of said first column to form a pressure seal therewith.
11. The high pressure applicator of claim 9, further comprising at
least one sealing element mounted to said first end portion and
adapted to form a pressure seal between said inner wall and said
plunger element.
12. The high pressure applicator of claim 9, further comprising a
handle integrally formed with or affixed to and extending radially
from said second column to provide the user a mechanical advantage
upon grasping said handle.
13. The high pressure applicator of claim 11, wherein said at least
one sealing element comprises an O-ring.
14. The high pressure applicator of claim 11, further comprising at
least one frictional element mounted to said second end portion and
adapted to form a friction fit with said second column at or near
said second closed end.
15. The high pressure applicator of claim 3, further comprising
threading for at least a portion of said inner wall of said first
column, and wherein said wall of said second column is an external
wall comprising threading along at least a portion thereof, said
threading of said external wall being engageable with said
threading on at least a portion of said inner wall.
16. The high pressure applicator of claim 15, wherein said
threading on said external wall engages with said threading on said
inner wall to form a pressure seal therebetween.
17. The high pressure applicator of claim 15, further comprising at
least one sealing element mounted to an end portion of said second
column and adapted to form or enhance a pressure seal with said
inner wall.
18. The high pressure applicator of claim 17, wherein said at least
one sealing element comprises an O-ring.
19. The high pressure applicator of claim 17, wherein said at least
one sealing element comprises a Teflon wrap.
20. The high pressure applicator of claim 1, wherein said handle is
integrally formed with or affixed said first column.
21. The high pressure applicator of claim 15, wherein said threads
cover only a portion of said second column external wall, an end
portion of said second column being relatively smooth.
22. The high pressure applicator of claim 21, wherein only a
portion of said inner wall comprises threads, the remainder of said
inner wall being substantially smooth.
23. The high pressure applicator of claim 22, wherein said
relatively smooth end portion comprises a reduced diameter section
having an outside diameter less than an inside diameter of said
threads on said inner wall, and an enlarged section which closely
fits with said substantially smooth inner wall to form a pressure
seal therewith.
24. The high pressure applicator of claim 1, wherein said first
column comprises a hinged or removable section adapted to swing
open or be removed from said first column for drivably engaging
said first and second columns.
25. The high pressure applicator of claim 22, wherein said end
portion of said external wall closely fits with said remainder of
said inner wall to form a pressure seal therewith.
26. The high pressure applicator of claim 25, further comprising at
least one sealing element mounted to said end portion of said
second column and adapted to enhance said pressure seal.
27. The high pressure applicator of claim 25, wherein said at least
one sealing element comprises an O-ring.
28. The high pressure applicator of claim 1, further comprising a
syringe including a barrel portion and a plunger portion, wherein
said second column is substantially hollow and comprises an inside
wall, an open first end and a closed second end, and wherein said
barrel portion is received within said first column and said
plunger portion is received within said second column.
29. The high pressure applicator of claim 28, further comprising
threading on said outer wall of said first column and threading on
said inner wall of said second column, said threading on said
second column being engageable with said threading on said first
column.
30. The high pressure applicator of claim 28, further comprising a
handle integrally formed with or affixed to and extending radially
from said second column to provide the user a mechanical advantage
upon grasping said handle.
31. The high pressure applicator of claim 28, wherein an end of
said barrel portion abuts against said substantially closed end of
said first column and an end of said plunger portion abuts against
said closed end of said second column, wherein driving of said
second column with respect to said first column provides a driving
force for advancing said plunger portion within said barrel
portion.
32. The high pressure applicator of claim 29, wherein said barrel
portion further comprises a wing or flanged portion adjacent an
open end thereof; and said first column comprises a first portion
adjacent said open end and a second portion adjacent said
substantially closed end and a transitional portion joining said
first and second portions, wherein said first portion has an inside
diameter larger than an inside diameter of said second portion, and
wherein said transitional portion is adapted to abut against said
wing or flanged portion.
33. The high pressure applicator of claim 1, further comprising a
syringe including a barrel portion and a plunger portion, wherein
said syringe is received within said first column.
34. The high pressure applicator of claim 33, further comprising a
handle integrally formed with or affixed to and extending radially
from said second column to provide the user a mechanical advantage
upon grasping said handle.
35. The high pressure applicator of claim 33, further comprising
threading on at least a portion of said inner wall of said first
column, and wherein said second column comprises an end adapted to
abut an end of said plunger portion and an external wall including
threading along at least a portion thereof, said threading of said
external wall being engageable with said threading on at least a
portion of said inner wall.
36. The high pressure applicator of claim 35, wherein an end of
said barrel portion abuts against said substantially closed end of
said first column, wherein driving of said second column with
respect to said first column provides a driving force for advancing
said plunger portion within said barrel portion.
37. The high pressure applicator of claim 35, wherein said barrel
portion further comprises a wing or flanged portion adjacent an
open end thereof, and said first column comprises a first portion
adjacent said open end and a second portion adjacent said
substantially closed end and a transitional portion joining said
first and second portions, wherein said first portion has an inside
diameter larger than an inside diameter of said second portion, and
wherein said transitional portion is adapted to abut against said
wing or flanged portion.
38. The high pressure applicator of claim 1, wherein said
applicator is capable of generating pressures of at least about
1000 psi.
39. The high pressure applicator of claim 1, wherein said
applicator is capable of generating pressures of at least 1500
psi.
40. The high pressure applicator of claim 1, wherein said
applicator is capable of generating pressures up to about 2000
psi.
41. The high pressure applicator of claim 1, wherein said
applicator is capable of generating pressures up to about 2500
psi.
42. The high pressure applicator of claim 1, wherein said
applicator is capable of generating pressures up to about 3000
psi.
43. A high pressure applicator for driving the delivery of a
flowable tissue implant material, comprising: a first column having
an inner wall, an outer wall, a first open end and a second
substantially closed end having an orifice therethrough; a second
column adapted to overfit at least a portion of said first column,
said second column having an inner wall, an outer wall, an open end
and a closed end; and a plunger element having a first end portion
adapted to be inserted within said first column and a second end
portion adapted to abut said closed end of said second column.
44. The high pressure applicator of claim 43, further comprising
threads on at least a portion of said outer wall of said first
column and threads on at least a portion of said inner wall of said
second column, said threads on said second column being engageable
with said threads on said first column.
45. The high pressure applicator of claim 43, wherein said first
end portion is adapted and configured to closely fit within said
inner wall of said first column to form a pressure seal
therewith.
46. The high pressure applicator of claim 43, further comprising at
least one sealing element mounted to said first end portion and
adapted to form a pressure seal between said inner wall of said
first column and said plunger element.
47. The high pressure applicator of claim 46, wherein said at least
one sealing element comprises an O-ring.
48. The high pressure applicator of claim 43, further comprising at
least one frictional element mounted to said second end portion and
adapted to form a friction fit with said second column at or near
said closed end.
49. The high pressure applicator of claim 48, wherein said at least
one frictional element comprises an O-ring.
50. The high pressure applicator of claim 43, wherein said second
end portion of said plunger element comprises a spherical
surface.
51. The high pressure applicator of claim 43, further comprising a
handle fixedly attached to said first column and radially extending
therefrom to provide a user a mechanical advantage upon grasping
said handle.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of application
Ser. No. 09/053,108, filed April 1, 1998, entitled "Pressure
Applicator for Hard Tissue Implant Placement", pending. Application
Ser. No. 09/053,108 is hereby incorporated by reference in its
entirety.
TECHNICAL FIELD
[0002] The present invention relates to instruments for more
accurately controlling the placement of implant material thereof,
during surgical procedures for the repair of hard tissue by
injection of hard tissue implant materials. Procedures for such
repair include hip augmentation, mandible augmentation, and
particularly vertebroplasty, among others.
BACKGROUND ART
[0003] Polymethylmethacrylate (PMMA) has been used in anterior and
posterior stabilization of the spine for metastatic disease, as
described by Sundaresan et al., "Treatment of neoplastic epidural
cord compression by vertebral body resection and stabilization." J
Neurosurg 1985;63:676-684; Harrington, "Anterior decompression and
stabilization of the spine as a treatment for vertebral collapse
and spinal cord compression from metastatic malignancy." Clinical
Orthodpaedics and Related Research 1988;233:177-197; and Cybulski,
"Methods of surgical stabilization for metastatic disease of the
spine." Neurosurgery 1989;25:240-252.
[0004] Deramond et al., "Percutaneous vertebroplasty with
methyl-methacrylate: technique, method, results [abstract]."
Radiology 1990;117 (suppl):352, among others, have described the
percutaneous injection of PMMA into vertebral compression fractures
by the transpedicular or paravertebral approach under CT and/or
fluoroscopic guidance. Percutaneous vertebroplasty is desirable
from the standpoint that it is minimally invasive, compared to the
alternative of surgically exposing the hard tissue site to be
supplemented with PMMA or other filler.
[0005] The general procedure for performing percutaneous
vertebroplasty involves the use of a standard 11 gauge Jamshidi
needle. The needle includes an 11 gauge cannula with an internal
stylet. The cannula and stylet are used in conjunction to pierce
the cutaneous layers of a patient above the hard tissue to be
supplemented, then to penetrate the hard cortical bone of the
vertebra, and finally to traverse into the softer cancellous bone
underlying the cortical bone.
[0006] A large force must be applied by the user, axially through
the Jamshidi needle to drive the stylet through the cortical bone.
Once penetration of the cortical bone is achieved, additional
downward axial force, but at a reduced magnitude compared to that
required to penetrate the cortical bone, is required to position
the stylet/tip of the cannula into the required position within the
cancellous bone. When positioned in the cancellous bone, the stylet
is then removed leaving the cannula in the appropriate position for
delivery of a hard tissue implant material to reinforce and
solidify the damaged hard tissue.
[0007] A syringe is next loaded with polymethyl methacrylate (PMMA)
and connected to the end of the cannula that is external of the
patient's body. Pressure is applied to the plunger of the syringe
to deliver the PMMA to the site of damaged bone at the distal end
of the cannula. Because in general, 10 cc syringes are only capable
of generating pressures of about 100-150 psi, this places a
limitation on the viscosity of the PMMA that can be effectively
"pushed through" the syringe and cannula and fully delivered to the
implant site. Of course, the use of a small barrel syringe, e.g., a
1 cc syringe, enables the user to generate higher driving
pressures. For example, pressures of 1000 psi and possibly as high
as 1200-1500 psi (depending upon the strength of the user and the
technique) may be generated using a 1 cc syringe. A serious
limitation with the use of a 1 cc syringe, however, is that it will
not hold a large enough volume to complete the procedure in one
step or "load" and must be reloaded several times to complete the
procedure, since, on average, about 3.5 cc of implant material per
side of the vertebral body are required for an implantation
procedure. This makes the procedure more complicated with more
steps, and more risky in that the polymerization of the implant
material causes it to become increasingly more viscous during the
additional time required for reloading. Another problem with a 1 cc
syringe is lack of control, as high pressures are generated in a
"spike-like" response time and are not continuously
controllable.
[0008] A viscous or paste-like consistency of PMMA is generally
believed to be most advantageous for performing percutaneous
vertebroplasty. Such a consistency insures that the implant
material stays in place much better than a less viscous, more
liquid material. Leakage or seepage of PMMA from the vertebral
implant site can cause a host of complications some of which can be
very serious and even result in death. For example, Weil et al.
reported cases of sciatica and difficulty in swallowing which were
related to focal cement leakage, Radiology 1996;Vol 199, No. 1,
241-247. A leak toward the distal veins poses an even more serious
risk, since this can cause a pulmonary embolism which is often
fatal.
[0009] In addition to the viscosity effects noted above that
require greater pressure to deliver hard implant tissue material,
when such material (like PMMA) is implanted percutaneously, the
need to inject it through a relatively narrow needle or cannula
also greatly increases the need for a high pressure driver. Still
further, implantation of PMMA into a relatively closed implantation
site (e.g., trabecular bone) further increases the resistance to
flow of the PMMA, at the same time increasing the pressure
requirements of the driver. Thus, there is a need for a high
pressure applicator that has enough storage capacity to perform a
complete implantation procedure without having to reload the device
in the midst of the procedure, and which is consistently
controllable, for an even, constant application of pressure during
delivery of the entirety of the implant material.
[0010] Attempts have been made to increase the ability to apply
pressure to drive PMMA to the vertebral implant site by providing a
smaller barrel syringe, but this holds less volume and must be
refilled once or several times to deliver enough volume of PMMA to
the site. Since there is a limited amount of time to work with PMMA
before it begins to polymerize or set up, this type of procedure is
more difficult to successfully complete within the allotted time,
and thus poses an additional risk to the success of the
operation.
[0011] Accordingly, there exists a need for an improved apparatus
and procedure for controllably applying higher pressures to a
source of implant material, and particularly to hard tissue implant
materials, to successfully implant the material at the desired
location in a single batch, for the performance of vertebroplasty
and particularly, percutaneous vertebroplasty.
DISCLOSURE OF THE INVENTION
[0012] The present invention includes a high pressure applicator
for driving the delivery of a flowable tissue implant material. A
first column having an inner wall, an outer wall, a first open end
and a second substantially closed end is provided with an orifice
through the substantially closed end for passage implant materials
therethrough under high pressure. A second column is drivably
engageable with the first column to generate fluid pressure within
at least the first column. Preferably, a wall portion of the second
column is drivably engageable with one of an inner and outer wall
of the first column. A handle is preferably fixedly attached or
integral with the first column and may extend radially from the
first column to provide a user a mechanical advantage upon grasping
it.
[0013] At least one sealing element may be provided to interface
with the inner wall of the first column, to enhance the generation
of pressure in the first column. A handle is also preferably
integrally formed with or affixed to the second column and may
extend radially therefrom to provide a user a mechanical advantage
upon grasping it.
[0014] In one embodiment of the invention, threading is provided on
an outer wall of the first column. The second column is
substantially hollow, having an open first end, a closed second end
and threading on an inner wall thereof. The threading on the second
column in this embodiment is engageable with the threading on the
first column to provide a driving force for driving the second
column with respect to the first column. The second column may
include an extension integrally formed with or affixed thereto and
optionally having an end portion extending from the open end of the
second column. The extension is adapted to be inserted through the
open end of the first column and form a substantial pressure seal
with the inner wall of the first column.
[0015] Additionally, at least one sealing element may be provided
at or near the end portion of the extension to form or enhance a
pressure seal with the inner wall of the first column. The sealing
element(s) may be an O-ring(s), a grommet(s) or the like.
[0016] In another embodiment, a plunger element is provided which
is adapted to be inserted within the first and second columns. The
plunger element has a first end portion and a second end portion,
where the first end portion is adapted and configured to closely
fit within the inner wall of the first column to form a pressure
seal therewith. At least one sealing element may be provided for
the first end portion to form and/or enhance a pressure seal
between the inner wall and the plunger element. A handle may be
integrally formed with or affixed to the second column, to
optionally extend radially therefrom, to provide the user a
mechanical advantage upon grasping it. The plunger element may
further be provided with at least one frictional element mounted to
the second end portion and adapted to form a disengageable friction
fit with the second column at or near the closed end of the second
column.
[0017] A high pressure applicator according to the present
invention may include threading on at least a portion of the inner
wall of the first column, and the second column may have threading
on at least a portion of an external wall thereof such that the
threading of the external wall is engageable with the threading on
at least a portion of the inner wall of the first column to provide
a driving mechanism for driving the second column with respect to
the first column. The interengaging threads may be formed to
closely fit to form a pressure seal therebetween upon their
engagement. At least one sealing element may be mounted to an end
portion of the second column and adapted to form or enhance a
pressure seal with the inner wall thereby forming or enhancing the
pressure seal between the first and second columns. The sealing
element(s) may comprise an O-ring(s), a Teflon wrap(s), or the
like. A handle may be integrally formed with or affixed to the
second column to extend radially therefrom, to provide a user a
mechanical advantage upon grasping it.
[0018] Various portions of a pressure applicator may be sized to
provide sufficient mechanical advantage to enable the application
of pressures up to about 3000 or 4000 psi by hand. The mechanical
advantage of an applicator is determined in large part by handle
size, the bore size of the first column, and the mechanical
advantage of the engagement mechanism. With regard to the engaging
threads used as an engagement mechanism, manufacturing and material
considerations, and the diameter on which to place the threads will
determine the thread pitch which may be used. This in turn
determines the mechanical advantage of this engagement mechanism.
Where a greater mechanical advantage is desired, a finer thread
pitch will provide the same. To achieve this, the diameter of
threaded sections of the first and second columns may be decreased.
Alternately, a finer pitch thread may be used on a relatively
larger diameter section by changing material or manufacturing
procedure (such as cutting the threads into the respective members
rather than molding the pieces as is presently preferred). In all,
a pressure applicator produced according to the present invention
is a balancing of various design goals relating to performance and
cost.
[0019] In an arrangement where the threads cover only a portion of
the external wall, the remainder of this wall of the second column
is left relatively smooth. In this arrangement, only a portion of
the inner wall of the first column has threads, and the remainder
of the inner wall is left substantially smooth. The relatively
smooth end portion of the second column has a reduced diameter
section having an outside diameter less than an inside diameter of
the threads on said inner wall, to allow assembly or interfitting
of the two columns. An enlarged section extending from the reduced
diameter portion closely fits with the substantially smooth inner
wall to form a pressure seal therewith. The first column in this
arrangement additionally includes a hinged or removable section
adapted to swing open or be removed therefrom to allow insertion of
the second column. At least one sealing element, which may be an
O-ring or the like, may be mounted to the end portion of the second
column to form or enhance a pressure seal therewith.
[0020] In yet another embodiment, the first column is substantially
hollow and comprises an inside wall, an open first end and a closed
second end, and a barrel portion of a syringe is received therein.
A plunger portion of the syringe is received within a second
column. The applicator may include threading on an outer wall of
the first column and threading on an inner wall of the second
column, where the threads are engageable with one another to
provide a driving force for driving the plunger portion with
respect to the barrel portion. A handle may be integrally formed
with or affixed to the second column and optionally extend radially
therefrom and to provide the user a mechanical advantage upon
grasping it.
[0021] An end of the barrel portion of the syringe may abut against
the substantially closed end of the first column and an end of the
plunger portion may abut against the closed end of said second
column, such that driving of the second column with respect to the
first column provides a driving force for advancing the plunger
portion within the barrel portion. The barrel portion may further
include a wing or flanged portion adjacent an open end thereof. The
first column may have a first portion adjacent the open end, a
second portion adjacent the substantially closed end and a
transitional portion joining the first and second portions, where
the first portion has an inside diameter larger than an inside
diameter of the second portion. In this case, the transitional
portion may be adapted to abut against the wing or flanged portion,
to provide additional or alternative support for the barrel portion
as the plunger portion is being advanced with respect thereto.
[0022] Alternatively, a high pressure applicator according to the
present invention may include a syringe having a barrel portion and
a plunger portion, where the syringe barrel is received within the
first column where threading is provided on at least a portion of
the inner wall of the first column and on at least a portion of an
external wall of the second column. In this embodiment of the
invention, the second column includes an end adapted to abut an end
of the plunger portion of the syringe and threading of the external
wall is engageable with the threading on at least a portion of the
inner wall to provide a driving force. The operation and variations
of this embodiment are substantially like those described directly
above.
[0023] A method of preparing a high pressure applicator for driving
the delivery of a flowable tissue implant material for use is
disclosed to include: providing an applicator having a first column
having an inner wall, an outer wall, a first open end and a second
substantially closed end having an orifice therethrough, and a
second column drivably engageable with the first column to generate
a pressure within the first column; loading the flowable tissue
implant material into the first column; engaging the second column
with the first column to enclose the tissue implant material; and
advancing the second column toward the first column to generate a
pressure for driving the flowable tissue material through the
orifice.
[0024] The second column may include a plunger adapted to form a
pressure seal with the inner wall of the first column, in which
case the engagement of the second column with the first column
includes introducing the plunger into the tissue implant material
in such a way to avoid the introduction of air bubbles or other
compliant matter together with the implant material to be delivered
to a patient. Advancement of the second column toward the first
column generates a pressure for driving the flowable tissue
material through the orifice, which may be at least 1000 psi.
Optionally, a substantially non-compliant tube may be connected to
the orifice prior to advancing the second column toward the first
column to generate a pressure for driving the flowable tissue
material through the orifice.
[0025] As another option, a substantially non-compliant tube may be
connected to the orifice after advancing the second column toward
the first column to generate a pressure for driving the flowable
tissue material through the orifice, thereby purging the orifice
prior to connecting the substantially noncompliant tube. In either
case, the substantially noncompliant tube may be, but is not
necessarily prefilled (e.g., with saline or implant material) prior
to connecting it to the orifice.
[0026] Loading of the first column with implant material may be
done in such a way as to slightly overfill the first column to form
a meniscus created by surface tension of the implant material. In
this case, the engagement of the first and second columns then may
include introducing a plunger element into the implant material and
then driving the plunger via the advancement of the second
column.
[0027] A method of preparing a high pressure applicator for driving
the delivery of a flowable tissue implant material for use is
provided which includes: providing an applicator containing at
least 5 cc of tissue implant material therein; and actuating the
applicator to generate an internal pressure of at least 1000 psi
which acts as a driving force to force a flow of the implant
material from the applicator. The pressure generated may be at
least 1500 psi, at least 2000 psi, at least 2500 psi or up to about
3000 psi.
[0028] Further, the method is described as torquing a first portion
of the applicator with respect to a second portion of the
applicator actuator to generate the driving force. The applicator
may be provided to contain at least 7.5 cc of tissue implant
material, up to 10 cc of tissue implant material, or even up to
about 15 cc of tissue implant material therein. A preferred
embodiment currently holds about 9 cc of implant material.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Each of the following figures diagrammatically illustrates
aspects of the present invention. No aspect shown is intended to be
limited to the expression pictured.
[0030] FIG. 1 shows of an initial phase of insertion of a stylet
into an implant site;
[0031] FIG. 2 shows the stylet having penetrated the cortical bone
and approaching cancellous bone;
[0032] FIG. 3 shows the stylet having reached the desired site of
implantation;
[0033] FIG. 4 shows the positioning of a cannula by guiding it
along the stylet;
[0034] FIG. 5 shows the cannula in position at the desired site of
implantation, with the stylet still in position;
[0035] FIG. 6 shows a stage after the stylet has been removed and a
high pressure applicator has been mounted to the cannula;
[0036] FIG. 7 shows the high pressure applicator used in FIG.
6;
[0037] FIG. 8 shows an alternative embodiment of a high pressure
applicator according to the present invention;
[0038] FIG. 9 shows another embodiment of a high pressure
applicator according to the present invention;
[0039] FIG. 10 shows an embodiment of a pressure applicator
according to the present invention in which a portion of the column
74 has been cut away to show the relationship between the column or
shaft 76 and column 74;
[0040] FIG. 11 shows a variation of the pressure applicator in FIG.
10 in which a portion of the column 74' has been cut away to show
the relationship between the column or shaft 76' and column
74';
[0041] FIG. 12A shows the column 74' in FIG. 11 with an opening
formed by removal of a hinged or removable section;
[0042] FIG. 12B shows the removable section 82 of column 74'
[0043] FIG. 12C shows the removable section taken along section
line 12-12 in FIG. 12B;
[0044] FIG. 13 shows another embodiment of a pressure applicator
according to the present invention;
[0045] FIG. 14 shows still another embodiment of a pressure
applicator according to the present invention;
[0046] FIG. 15 shows a high pressure applicator after being loaded
with a hard tissue implant material and assembled;
[0047] FIG. 16 shows an alternative embodiment of the high pressure
applicator in FIG. 6;
[0048] FIG. 17 shows the high pressure applicator used in FIG.
16;
[0049] FIG. 18 shows an arrangement for high pressure,
substantially non-compliant delivery of an implant material;
[0050] FIG. 19 shows a cannula and two types of stylets useable
with the present invention and indicates the manner in which they
are assembled;
[0051] FIG. 20 shows a high pressure applicator having an enlarged
introduction section, a substantially noncompliant tubing, a
cannula and a stylet for use in performing a percutaneous
implantation;
[0052] FIG. 21 shows the first column and a portion of the handle
of the high pressure applicator in FIG. 20;
[0053] FIG. 22 shows alternate configurations of an end of the
first column and an independent funnel useable with each;
[0054] FIG. 23A shows a partially cut away view of a housing
member, retainer member and plunger;
[0055] FIG. 23B shows an end view of FIG. 23A; and
[0056] FIG. 23C is a sectional view of FIG. 23A showing the
engagement of the plunger with the housing member.
BEST MODE FOR CARRYING OUT THE INVENTION
[0057] The present invention substantially improves the delivery of
hard tissue implant sites to the targeted zone of implantation, and
is especially well suited for percutaneous deliveries. The present
invention substantially reduces several of the risk factors
associated with the performance of percutaneous vertebroplasty.
Additionally, the present invention enables an increase in an upper
acceptable viscosity value of the implant to be delivered because
of the increase in the amount of pressure available for
controllably driving the delivery.
[0058] An example of a procedure for performing percutaneous
vertebroplasty is illustrated in FIGS. 1-6. Beginning with FIG. 1,
an example of the use of depth guided instruments will now be
described. For a more detailed description of various depth-guided
instruments that can be used for accessing the cortical bone, the
reader is directed to copending application Ser. No. 08/950,382,
filed on Oct. 14, 1997, entitled "Precision Depth Guided
Instruments for Use in Vertebroplasty"; and copending application
Ser. No. 08/949,839, filed on Oct. 14, 1997, entitled "Precision
Depth Guided Instruments for Use in Vertebroplasty". Both
applications, numbered Ser. No. 08/950,832 and Ser. No. 08/949,839
are hereby incorporated by reference in their entireties. A
currently preferred stylet 1' and cannula 10', and an optional
direction guiding stylet 1" are shown in FIG. 19. A detailed
description of these devices and their uses are disclosed in a
co-owned application filed concurrently herewith, entitled
"Precision Instruments for Use in Vertebroplasty", and bearing
Attorney Docket No. 361722000420. The aforementioned application
bearing Attorney Docket No. 361722000420 is hereby incorporated by
reference in its entirety.
[0059] In the example shown in FIG. 1, a stylet 1 is provided which
has a length that is more than sufficient to span the distance from
the epidermis of a patient to the cancellous bone tissue in the
vertebra, in the preferred configuration. Typically the length of
the stylet would be about three inches or greater, but lesser
lengths may also be employed as well, depending on the size of the
patient. Of course, if other hard tissues are to be accessed, the
length of the stylet can be readily modified without departing from
the inventive features of the present invention.
[0060] The stylet 1 is preferably made of a surgical grade of
stainless steel, but other known equivalent biocompatible metals
and materials may be used for the same purpose. Ideally, the
stylet, or at least a distal end thereof, will be radiopaque so
that it can be monitored using fluoroscopy, CT or other imaging
techniques during the procedure to help determine the depth and
location of the penetration.
[0061] A first or distal end of the stylet 1 ends in a point 2
which is sharp and adapted to penetrate hard tissue when axially
loaded. Extending from the tip 2 are self-tapping threads 4. The
self-tapping threads 4 provide an advantage in that once the tip 2
has penetrated the cortical bone (e.g., see FIG. 2), the operator
of the stylet can then proceed to advance the stylet by torquing
the stylet, which engages the self-tapping threads 4 in the
cortical bone 103 and begins to screw the stylet 1 into the
cortical bone 103. Rotation of the stylet 1 is continued, to
advance the stylet into the bone, while monitoring the advancement
with some type of imaging technique, e.g., fluoroscopy or
equivalent. It is noted that actual fluoroscopic views are
generally from a perspective other than that shown in the Figures.
However, for ease and clarity of illustration, the Figures depict a
transverse sectional view of the vertebra as the instruments enter
the vertebral body. Advancement is continued until the tip 2
reaches the site at which it is desired to deliver the implant
material. Usually this site is in the cancellous bone as shown in
FIG. 3, but could be anywhere within the bone where there is
osteoporosis, or a fracture or other defect or trauma.
[0062] A cannula 10 is provided which includes an elongated tubular
structure 111 to be positioned in the cancellous bone or other
implantation site for delivery of PMMA or other bone implant
material therein. The tubular structure 11 of the cannula 10 is
preferably made of a surgical grade of stainless steel, but may be
made of known equivalent materials, similarly to the stylet 1
discussed above. Preferably, at least a distal end of the tubular
structure is radiopaque. The tubular structure 11 has an inside
diameter which is only slightly larger than the outside diameter of
the stylet 1, so that the cannula may effortlessly pass axially
over the stylet, while at the same time being supported and guided
by the stylet. A first or distal end 12 of the cannula is
preferably (but not necessarily) beveled or tapered to ease the
penetration of the cannula through the cutaneous and soft tissues,
and especially through the hard tissues.
[0063] Surrounding the second end of the tubular structure 11 (or
11' in FIG. 19) is a connector 18 (FIGS. 6, 19) for linking the
cannula 10, 10' with a pressure applicator according to the present
invention, for supplying the PMMA or other implantable material
that is to be injected via tubular structure 11, 11'. Preferably,
connector 18 is a Luer-lock type of connector, but other known
connecting mechanisms may be successfully interchanged, e.g., a
flat bottom threaded hole, a conventional threaded hole, a threads
and locking nut arrangement, etc.
[0064] As shown in FIGS. 4-5, the cannula 10 is advanced over the
stylet, until visualization of the process indicates that the end
of the cannula 12 is substantially even with the tip of the stylet
2, whereby it is confirmed that the cannula is properly positioned
for delivery of the implant material. On the other hand, the
cannula 10' and stylet 1' are advanced together, which is currently
the preferred method of insertion. Next the stylet 1 is removed
from the site, either by reverse rotation or by simply withdrawing
it. At the same time the cannula 10 is maintained in position to be
readied for delivery of the implant material.
[0065] A pressure applicator 50 according to the present invention
is next mounted to the connector 18 at the end of cannula 10, as
shown in FIG. 6. The pressure applicator 50 is provided with a
fitting 52 which is designed to form a pressure tight connection
with the connector 18. As mentioned above, the preferred type of
connection is a Luer-lock type connection, but alternative,
equivalent types of connectors may be employed. The pressure
applicator further includes a first column 54 for receiving and
containing implant material. The first column 54 is open at one end
54a for receiving the material. At the other end 54b of the first
column is a much smaller opening or orifice which ends with the
connector or transfer fitting 52 or into which the connector or
transfer fitting is mounted or placed (e.g., by threading, bonding,
or the like).
[0066] A second column 56 is provided for overfitting first column
54 and providing a pressure seal therewith. Preferably, the second
column 56 has interior threads 58 as shown in phantom in the
exploded view of FIG. 7. The interior threads 58 mate or engage
with exterior threads 60 provided on the first column 54. However,
other equivalent types of drivable engaging arrangements, e.g., a
ratchet and pawl arrangement, interior threading arrangement in the
first column, or other equivalent arrangements could be used in
place of the mating threads, so long as adequate force is able to
be generated and maintained between the two columns for providing
the driving pressure for the implant material.
[0067] Column 56 is open at end 56a for receiving the first column
54 therein. At the opposite end 56b, column 56 is closed to enable
a generation of pressure within the two columns as they are moved
toward one another and column 56 passes over column 54. Preferably,
at least one sealing element 57 (e.g., a square, round or other
type of O-ring, grommet, wrap of material or the like) is provided
to maintain a high pressure fitting between the columns 54 and 56
to better enable a high pressure driving force to be generated for
driving implant material from within the device through the opening
54b. The sealing element(s) 57 may also be provided integrally with
the column 55, e.g., by flaring out the column material to provide
an interference fit, or the like. Since implant materials to be
used in the invention (e.g. PMMA) are often very viscous, a high
pressure capacity ensures that even thicker or more viscous mixes
of implant material may be driven by the applicator 50.
[0068] An advantageous implant material that may be used with the
high pressure applicator of the present invention is a PMMA bone
cement including contrast agents and/or tracer particles. Aspects
of such a material are described in U.S. patent application Ser.
No. 08/950,256, "Enhanced Visibility Materials For Implantation In
Hard Tissue" (Attorney Docket 361722000200) by Preissman, filed
Oct. 14, 1997. Contrast radiographic powder or particles of any
typical material and of a size between 0.5.mu. to 1000.mu. may be
included.
[0069] To form the requisite seal to drive the implant material, a
separate "sealing" element need not necessarily be provided.
However, especially where highly viscous materials are concerned,
the O-ring or grommet optionally provided is preferred since it can
move on the plunger rotationally and thus even if the plunger is
turning with the handle, the seal can move independently.
[0070] Returning to the applicator in the embodiment of FIG. 7,
however, a plunger element 55 is provided to be slidably driven by
the first column 56 into the second column 54. At least one O-ring
57 or equivalent sealing mechanism is mounted near a first end 55a
of the plunger element 55 to provide a friction fit between the
plunger element 55 and the interior wall of the first column 54. In
use, the plunger element 57 is "started" in the end 54b of the
column 54, by inserting a small length of the plunger element 57 to
an extent which is at least enough to seat the O-ring 57 with the
inner wall of the column 54. Next the second column 56 is initially
connected with the column 54 by mating the threads 58 and 60.
Subsequent torquing of the handle 62 advances the closed end 56b of
the column 56 toward the second end 55a of the plunger element 55
until it makes contact therewith. Continued torquing of the second
column 56 with respect to the first column 54 advances the plunger
element 55 against the implant material 66 (not shown in FIG. 7).
Sealing element 57, in combination with the advancement of the
plunger element 55, generates a pressurized driving force which
results in expulsion of the implant material from end 54b of the
second column 54.
[0071] A handle 62 is mounted on the column 56 to provide
additional leverage for driving the column 56 with respect to
column 54. In the example shown in FIGS. 6 and 7, the handle 62 is
provided at the closed end 56b to provide a greater mechanical
advantage for torquing column 56 about its longitudinal axis. Of
course, the handle could be provided anywhere along the column 56
so long as it extends the effective radius for torquing about the
longitudinal axis. A handle 64 is fixedly attached, molded, or
otherwise mounted to the first column 54. The handle 64 may be
grasped by the operator and provides leverage against rotation of
the first column 54 during driving of the second column 56.
Preferably, the handle 64 is in the form of a lever as shown in
FIG. 6, but alternative embodiments of the handle may include a
circular handle, etc. so long as a sufficient mechanical advantage
is provided to the user.
[0072] For other types of driving mechanisms, other types of
handles might be employed. For example, a lever might extend from
the column in an embodiment using a ratchet and pawl type of
driving mechanism.
[0073] The above described components of the pressure applicator 50
are all preferably formed of amorphous nylon or ABS plastic, with
at least column 54 being formed of clear or translucent amorphous
nylon. However, any other materials which are durable,
sterilizable, biofriendly and chemically compatible with the
material to be implanted (e.g., stainless steel) could be readily
substituted. As a further example, although polycarbonate is not
recommend for implanting PMMA, it may be fully acceptable for use
in implanting other types of materials with which it has better
chemical compatibility.
[0074] Although the plunger element 55 is shown as a separate
component in the embodiment of FIG. 7, it is noted that this
element may be integrally formed with the column 56', as shown in
the embodiment of FIG. 8, to form an extension 56c' of the second
column 56'. As shown by the phantom lines, the extension 56c' is
integrally formed or affixed to the closed end 56b' of the column
56' and extends the length thereof to emerge from the open end and
extend therefrom to allow the sealing end and sealing element 57 to
be inserted into the column 54, prior to starting the
interengagement of threads 58 and 60. Note that threads 58 are not
indicated in phantom, or at all, in FIG. 8 for purposes of
simplification of the Figure and to allow the phantom lines
depicting the extension 56c' more clearly. It is further noted that
the extension 56c' does not have to take the form of the plunger
55, but may have a much smaller cross section where it extends from
the closed end. For example, the extension 56c' may be formed as a
much smaller rod with a first end having the same dimensions as
that shown in FIG. 8, to provide a proper seal with the column
54.
[0075] FIG. 9 shows another embodiment of a pressure applicator 50"
according to the present application. Pressure applicator 50" is
provided with a plunger element 55" which includes sealing element
57 and frictional element 59, both preferably O-rings, at opposite
ends thereof. The sealing and frictional arrangements are not
limited to the placement of one O-ring or equivalent but may use
two or another multiple of sealing elements. Frictional element 59
is provided to form a friction fit inside the closed end 56b" of
the column 56". Thus, the plunger element 55" is inserted into the
column 56" initially until the end 55b" bottoms out against the
closed end 56b" and the frictional element 59 forms a friction fit
with the inner wall of the column 56" adjacent the closed end 56b".
The friction fit is sufficient to maintain the plunger element 55"
in position within the column 56" even when the column is held
vertically, by the handle 62, with the open end 56a" pointing
downward.
[0076] Additionally, after implant material is loaded into the
column 54, and the end 55a" and sealing element 57 are started into
the column 54 to seat the sealing element 57 against the inner wall
of the column 54, the friction fit between sealing element 57 and
column 54, in combination with the friction fit between the sealing
element 59 and column 56" act to prevent rotation of the plunger
element with respect to the column 54 as the plunger element is
advanced into the column by the driving force of the column 56".
Specifically, the frictional forces between the sealing element 57
and the column 54 are greater than those between the sealing
element 59 and the column 56" so that the sealing element 59 slips
against the inner wall of the column 56" as the column 56" is
torqued to advance both the column 56" and the plunger element 55"
with respect to the column 54. By this action, the rotational
movement of the closed end 56b" of the column 56" is converted to a
solely translational force against driving the plunger element 55".
This feature is particularly important when the implant material
comprises PMMA, as PMMA is somewhat abrasive. If the plunger
element 55" and sealing element 57 are allowed to rotate or are
driven to rotate with respect to the column 54, this may allow some
of the PMMA to work its way between a portion or all of the sealing
element 57 and inner wall of the column 54 where it can act as an
abrasive to prematurely degrade the sealing element 57 and/or the
wall of the column 54. By eliminating rotation of the sealing
element 57 with respect to the inner wall of the column 54 so
purely translational or sliding movement occurs upon actuation of
the applicator, migration of PMMA between the sealing element 57
and column 54 wall are minimized or eliminated.
[0077] The end 55b" and sealing element 59 as shown have dimensions
slightly larger than those of the end 55a" and sealing element 57
to account for the slightly larger inside diameter of the column
56" relative to the inside diameter of the column 54. However, it
is not necessary to use these dimensions, since a recess (not
shown) having a smaller diameter can be formed (by boring, molding
or otherwise) into the closed end 56b" so that a smaller end 55b"
and sealing element 59 can be employed to form a friction fit
therewith.
[0078] Another variant of a frictional element useable to prevent
rotation of the plunger or rod upon actuation of the applicator is
pictured in FIGS. 23A-23C. The enlarged base 55b'" of the
piston/plunger rod 55'" includes and end 55d having a spherical
surface which is free to rotate with respect to the inner end
surface 56d of the second column 56. The enlarged base 55b'" is
held in position by the placement of one or more (preferably two)
internal retaining rings 59 which engage within a recess in second
column 56 and abut the enlarged base 55b'" to substantially prevent
translational movement thereof with respect to the second column
56. Thus the rod 55'" will not fall out of the second column 56
when inverted or otherwise jostled, but the rod 55'" is still
allowed to turn relative to the column 56.
[0079] FIG. 10 is a partial sectional view of an embodiment of a
pressure applicator 70, according to the present invention, in
which a portion of the column 74 has been cut away to show the
relationship between the column or shaft 76 and column 74. In this
embodiment, column 74 is interiorly threaded with threads 71 which
mate with threads 78 on the exterior of column 76. A sealing
element 77 (e.g., an O-ring, Teflon wrap (formed by wrapping with
Teflon tape, for example) or other equivalent) may be mounted at or
near the end of the column 76 to enhance the pressure seal between
the columns 76 and 74, although close tolerance threads may be
employed to generate sufficient pressure without the use of a
sealing element. Although not shown, a handle is also preferably
mounted to the column 74 (e.g., similar to the handle 64 described
above or to handles described below) to assist the user in
developing the torque needed to generate high pressures. A handle
72 is mounted to column 76 to further assist in generating
torque.
[0080] FIG. 11 is a partial sectional view of a variation of an
embodiment of a pressure applicator 70', according to the present
invention, in which a portion of the column 74' has been cut away
to show the relationship between the column or shaft 76' and column
74'. In this embodiment, the threads 71' are radially inset from
the remainder of the inner wall 73' of column 74' which is left
smooth. Threads 78' are exteriorly provided on column or shaft 76'
which mate with threads 71'. The distal end of shaft 76' is
provided with an enlarged portion 79 which closely approximates or
mates with the smooth inner wall 73'. A sealing element 77' (e.g.,
an O-ring, Teflon tape or other equivalent) may be mounted at or
near the end of the enlarged portion 79 to enhance the pressure
seal between the columns 76' and 74'. A handle 75 is also
preferably mounted to the column 74' to assist the user in
developing the torque needed to generate high pressures. Although
handle 75 is shown mounted to the proximal end of the column 74',
it is noted that the handle may also be mounted to the distal end,
similar to that described with respect to handle 64 above, or at
virtually any location along the length of the column that may be
desirable, and still achieve the advantages of enhancing torque
generation. Also, the handle 75 may be molded or otherwise formed
integrally with the column 74' or, alternatively, may be fixedly
mounted to the column 74' (e.g., by bonding, welding, splined or
other mechanical arrangement) to provide torque to the column 74'
without slipping with respect thereto. A handle 72 is mounted to
column 76' to further assist in generating torque.
[0081] Column 74' must be provided with an access as shown in FIG.
12A, to allow insertion of the shaft 76', since the outside
diameter of the enlarged portion 79' is greater than the diameter
of the distal opening 74a' of the column 74'. One example of
providing such an access, is to provide a hinged or removable
section 82 which may be swung open or removed from the remainder of
the column 74' during the insertion of the column 76'. In the
example shown in FIGS. 11-12C, section 82 includes a hinge pin 84
which is insertable into a recess 86 in the wall of the remainder
of the column 74' for pivoting therewith, or allowing removal of
the section altogether. Other types of hinges or movable
attachments may be readily substituted for the hinge pin 84 and
recess 86 as would be apparent to those of ordinary skill in the
art.
[0082] One or preferably both edges of the section 82 may be
provided with flanges 88 or similar extensions to provide a snap or
friction fit with the remainder of the column 74' when the section
82 is installed. Further optionally, the inner wall of the
remainder of the column may be provided with a recess or groove 87
to receive the flange or extension 88 to provide a more secure
interlock. Additionally or alternatively, the column 74' may be
provided with a clamp or tying band (not shown) to surround the
section 82 and column 74' and compress the two pieces slightly to
maintain them in a secure relationship.
[0083] Insertion of the column 76' is performed by first removing
or swinging open the section 82 away from the remainder of the
column 74'. The proximal portion 76a' of the column 76' has a
smaller outside diameter than the threaded portion 78' and is also
sufficiently smaller than the inside diameter of the threads 71',
so that the enlarged portion 79 can be placed in the space 89 while
the proximal portion 76a' clears the threads 71'. The section 82 is
then replaced by snapping and/or clamping the same into position
against the remainder of the column 74', thereby surrounding the
proximal portion 76a' and enlarged portion 79. Threads 78' can then
be started with threads 71' to ready the applicator 70' for
application of a pressurized driving force.
[0084] FIG. 13 is a plan view of another embodiment of a pressure
applicator 90 according to the present invention. Column 94 is
configured and dimensioned to receive a disposable syringe 150
(shown in phantom lines) therein. For example, this embodiment can
be used with a 10 cc syringe, thereby enabling much greater
pressures to be generated than discussed above. The column 94 can
be formed as a two stage column, as shown, having a first inside
diameter 94c which is smaller than a second inside diameter 94d.
This design allows the barrel 152 of the syringe 150 to be received
in the portion 94c and abut against a tapered portion of the column
94e. Additionally, or alternatively, a transition collar 94f which
interconnects the varying diameter portions 94c and 94d of the
column 94, provides a surface against which the flange or "wings"
of the syringe barrel 152 abut. An alternative arrangement could
have a column having a single stage or inner diameter which could
rely on the tapered region 94e solely for abutment of the syringe
barrel 152.
[0085] The syringe plunger 154 is received in the larger diameter
portion 94d of the column 94 (which, in the alternative arrangement
described would be the single stage or diameter). A second column
or shaft 96 is externally threaded and external threads 98 are
designed to mate with internal threads (not shown) on the interior
wall of the column portion 94d. The distal end 96a of column 96
abuts against the end 158 of the syringe plunger 154 upon threading
the column 96 into column 94. Further torquing of the handle 92
with respect to the column 94 generates a driving force for
translationally advancing the syringe plunger 154 to generate a
high pressure driving force. A sealing element (not shown) is
preferably mounted at or near the distal end of the syringe plunger
154, as is known in the art, to enhance the pressure generation.
Although not shown, a handle is also preferably mounted to the
column 94 (e.g., similar to the handle 64 or 75 described above) to
assist the user in developing the torque needed to generate high
pressures.
[0086] FIG. 14 is a plan view of another embodiment of a pressure
applicator 90' according to the present invention. Column 94' is
configured and dimensioned to receive a disposable syringe 150
(shown in phantom lines) therein. The column 94' can be formed as a
two stage column, similar to that described above with regard to
FIG. 13, but is formed as a single stage or single diameter column
in FIG. 14. This design allows the barrel 152 of the syringe 150 to
be received in the column 94' and abut against a tapered portion of
the column 94e'. The syringe plunger 154 extends from the proximal
opening 94a' of the column 94 and is received in the column 96'.
Column 96' is internally threaded (threads not shown) and the
internal threads are designed to mate with external threads 93 on
column 94'. The closed proximal end 96b' of column 96' abuts
against the end 158 of the syringe plunger 154 upon receiving the
plunger 154 in column 96' and beginning mating of the internal
threads of the column 96' with threads 93. Further torquing of the
handle 92' with respect to the column 94' generates a driving force
for translationally advancing the syringe plunger 154 to generate a
high pressure driving force. A sealing element (not shown) is
preferably mounted at or near the distal end of the syringe plunger
154, as is known in the art, to enhance the pressure generation.
Although not shown, a handle is also preferably mounted to the
column 94' (e.g., similar to the handle 64 or 75 described above)
to assist the user in developing the torque needed to generate high
pressures.
[0087] In using the pressure applicator according to the present
invention to drive a tissue implant material, a tissue implant
material, in this example, a hard tissue implant material 66 is
loaded into the first column 54 and the second column 56 is
connected with the first column 54 in preparation for implantation,
see FIG. 15. Although the pressure applicator 50 is shown in FIGS.
6, 15 and 18, it is noted that the principles described with
respect thereto are generally applicable to each of the embodiments
described herein. Of course, minor variations in procedure may be
necessary, e.g., loading the syringe 150 with implant material,
rather than the pressure applicator column, when using the
embodiments of FIGS. 13 and 14, etc., but the general principles
described herein may be applied to any embodiment by those of
ordinary skill in the art. Prior to mounting the pressure
applicator 50 on the cannula 10, a tissue implant material 66 is
loaded into the first column 54 and the second column 56 is
connected with the first column 54 in preparation for implantation.
Optionally, the introduction of air bubbles can be further
substantially reduced or avoided by slightly overfilling the first
column to form a meniscus created by surface tension of the implant
material and then introducing the plunger element into the material
and driving the plunger into the first column. This optional
technique may be used in all of the disclosed embodiments, but may
be obviated by the features shown in the embodiments of FIGS.
20-22, as discussed below. The first column is then rotated
slightly with respect to the second column until a minimal amount
of tissue implant material is expressed from the fitting 52 end, to
ensure that no air has been entrapped in the applicator. The
cannula 10 is backfilled with saline, tissue implant material 66,
or other biocompatible fluid in order to displace the air
therefrom. The pressure applicator 50 is then mounted onto the
cannula 10 as described above and shown in FIG. 6. The operator
next grasps the handle 62 in one hand and the handle 64 in the
other and begins to torque the handle 62 while maintaining the
handle 64 in its position. When operated as described, the pressure
applicator is capable of generating pressures of about 1000 to 3000
psi within the columns, which is a high driving force that is
applied to the implantable material 66.
[0088] Torquing of the handle 62 with respect to the handle 64 is
continued until a sufficient amount of implant material 66 has been
delivered to the implant site as verified by an appropriate imaging
technique. A variety of endpointing techniques are described in the
application entitled "Precision Instruments for Use in
Vertebroplasty", and bearing Attorney Docket No. 36172-2000420,
which was incorporated by reference above. Advantageously, the
pressure applicator 50 allows a first column 54 which is large
enough in volume at least 5 cc, preferably at least 7.5 cc, and
more preferably at least 10 cc and up to about 15 cc to contain
sufficient implant material for an entire implantation process so
that there is no need to refill the column 54 in the midst of a
procedure. For uses that require the delivery of larger volumes of
implant material, the designs disclosed herein could be enlarged so
as to have a capacity up to 25 cc and even upwards of 30 cc. It
would further be apparent to those of ordinary skill in the art to
modify the designs herein to have capacities even larger than that
disclosed should an implantation procedure require larger volumes
of material.
[0089] A modification of the apparatus described above is shown in
FIG. 16. In this embodiment, cannula 10' includes a modified
tubular structure design. The first or distal portion 11a of the
tubular structure is of the same dimensions as the embodiment of
FIGS. 1-6. The second or proximal portion 11b of the cannula 10',
however, has a substantially larger diameter than that of the first
portion 11a. Preferably, the diameter of second portion 11b is
about twice the diameter of the first portion 11a, although any
increase in the diameter of the second portion 11b over that of the
first portion 1a will decrease the pressure requirement for
effective delivery of the material to be implanted.
[0090] The first and second portions 11a, 11b have approximately
equal lengths, but this is governed by the anatomy of the site to
be accessed. In the "average" percutaneous vertebroplasty
situation, the first portion 11a is required to be about 1.5" long,
as this is the length that is needed for traversing the cortical
bone of the pedicle. Thus, the first portion should not be
significantly enlarged due to the size constraints of the pedicle,
the safety risks to the spinal column and aorta which are increased
when the cannula size is increased intravertebrally, and by the
desire to remove as little bone as possible when entering with the
stylet and cannula, among other factors.
[0091] However, the portion of the cannula which will occupy the
soft tissues can be significantly expanded without substantially
adversely effecting the patient. Given the benefits of reducing the
required injection pressure and ensuring a better delivery of the
bone implant material, such a modification becomes a viable
option.
[0092] The pressure applicator 50'" is essentially the same as that
in the embodiment 50, with modifications as follows. The pressure
applicator 50'" is provided with a fitting 52'" (FIG. 17) which is
designed to form a pressure tight connection with the connector 18'
and is therefore of a significantly larger diameter than the
connector 52. Additionally, the first column 54'" is essentially
open at both ends 54a'" and 54b'" as it does not taper or tapers
much less than the previous embodiment at opening 54b'". As
mentioned above, the preferred type of connection is a Luer-lock
type connection, but alternative, equivalent types of connectors
may be employed.
[0093] Like pressure applicator 50, the components of the pressure
applicator 50'" are all preferably formed of amorphous nylon. The
housing or second column or any portions which do not contact the
implant material, may be formed of ABS plastic. Additionally, any
other materials which are durable, sterilizable, biofriendly and
nonreactive with the particular implant materials to be contained
therein, e.g., stainless steel, polypropylene, could be readily
substituted.
[0094] Although the above modifications with regard to FIG. 16 have
been described and shown as applied to the applicator 50, it is
noted that similar modifications can be effected with regard to
applicators 50', 50", 70, and 70'. It is further recognized that
even embodiments 90 and 90' could be so modified, although this
would also likely require modification of the disposable syringes
which might not then be as readily accessible commercially.
[0095] Prior to mounting the pressure applicator 50' on the cannula
10', a hard tissue implant material 66 is loaded into the first
column 54 and the second column 56 is connected with the first
column 54 in preparation for implantation. The pressure applicator
50' is then mounted onto the cannula 10' as shown in FIG. 16. The
operator next grasps the handle 62 in one hand and the handle 64 in
the other and begins to torque the handle 62. When operated as
described, the pressure applicator is capable of generating
controllable and sustainable pressures of up to about 3000 psi
within the columns, which is a high driving force that is applied
to the implantable material 66.
[0096] Alternative to the direct connection of the pressure
applicator 50 to the connector 18 via fitting 52, as shown in FIG.
6, a high pressure tubing 70 may be and preferably is
interconnected between the pressure applicator 50 and the cannula
10, as shown in FIG. 18. In addition to a high pressure rating, it
is preferable that the tubing be a substantially non-compliant
tubing, to obviate problems of "oozing" and overfilling that occur
when there is too much compliance in a high pressure implantation
system. Preferred examples of high pressure, substantially
non-compliant tubings include PEEK tubing, and other polymers such
as Nylon, PTFE, and FEP which may be radially reinforced with a
no-stretch coil such as a flat wire spring of stainless steel,
aramid fibers such as Kevlar, etc. A more detailed description of
high pressure, substantially non-compliant tubings which are
suitable for tubing 70 is given in copending application Ser. No.
09/276,062, filed Mar. 25, 1999 and entitled "Non-Compliant System
for Delivery of Implant Material". Application Ser. No. 09/276,062
is hereby incorporated herein its entirety, by reference
thereto.
[0097] Similar to previous modifications, this modification applies
to all other embodiments, in addition to the applicator 50 which is
specifically referred to. The tubing 70 has male 72 and female 74
connectors for forming pressure tight seals with fitting 52 and
connector 18, respectively. The tubing 70 enables both the
applicator 50, and thus the user's hands to be distanced from the
radiographic field or other viewing field, which is advantageous
both for safety purposes as well as improving the procedure. This
embodiment is particularly advantageous for the most frequent
set-ups where bi-planar viewing is performed and two imaging
devices are oriented at 90.degree. to one another about the
implantation site. One of the advantages which is gained that
improves the procedure, is that the viewing instrumentation can be
moved closer to the actual implantation site, thereby providing a
more magnified view.
[0098] It is preferred that the tubing 70 is mounted to the
pressure applicator prior to mounting on the cannula fitting 18.
After filling the pressure applicator with implant material as
described above, the tubing 70 is mounted to fitting 52. A small
amount of pressure is next applied to the implant material to
express the implant material until a minimal amount exits the open
end of the tubing (i.e., the end where connector 74 is located).
The tubing 70 is then connected to the connector 18 of the cannula
10 for implantation of the implant material into the desired
location. Although the foregoing is the desired order of connection
so that the air space in the tubing can be prefilled with implant
material, it is not the only possible progression for the
procedure. Alternatively, the tubing 70 can be connected to the
fitting 18 of the cannula 10 and the tubing 70 and cannula 10 are
then backfilled with saline, implant material, or other
biocompatible fluid to displace any air residing in the structures.
After filling of the pressure applicator 50 with implant material,
the tubing can be connected to the fitting 52 and implantation of
the implant material can be rapidly commenced thereafter.
[0099] FIG. 20 shows a high pressure applicator having an enlarged
introduction section, a substantially noncompliant tubing, a
cannula and a stylet for use in performing a percutaneous
implantation. High pressure applicator having the feature of an
enlarged introduction section are further disclosed and claimed in
a co-owned application filed concurrently herewith, entitled "High
Pressure Delivery System" and bearing attorney docket number
361722000700. The application filed concurrently herewith entitled
"High Pressure Delivery System" and bearing attorney docket number
361722000700 is hereby incorporated by reference thereto in its
entirety.
[0100] FIG. 21 is an enlarged detail showing of the first column 30
and a portion of the handle 40 of the high pressure applicator
shown in FIG. 20. The open end portion of the first column 30 is
formed as an introduction section 24 which has a slightly larger
cross-sectional area than that of the portion of the first column
30 adjacent to it. Providing a larger size or diameter introduction
section 24 enables the introduction of the plunger 44 into the
implant material without simultaneously forming a seal where
compliant bubbles may be trapped. Put another way, the differential
in sizes is provided so that when the smaller diameter portion of
the first column 30 is fully filled and the introduction section 24
is at least partially filled, the end of the plunger 44 which might
otherwise trap air bubbles resulting in system compliance will be
dipped in the implant material thereby allowing for the exclusion
of air bubbles prior to driving it into the smaller diameter
portion.
[0101] The introduction section 24 may be relatively close in size
to the adjoining smaller diameter portion to provide only a
surrounding dam for a meniscus poured over the smaller diameter
portion. Since the amount of material that needs to be provided in
the introduction section need not be great to facilitate the
venting or purging as described above, it is better to only
introduce slightly more implant material than will fill the smaller
diameter portion. Introduction of a larger amount of implant
material is not only wasteful, but may result in material drainage
out of the introduction section into other parts of the
applicator--especially when the applicator is inverted or turned as
will often be the case in preparing PMMA implant material for
delivery.
[0102] To help account for the possibility of excess implant
material and associated potential of fouling of the applicator with
such an excess, a larger size of the introduction section 24 than
strictly required for the venting feature discussed above may be
used to act as a catch basin for excess material. This will provide
a larger margin of error in pouring implant material into the
applicator before overflowing the introduction section 24 will
occur. Further, the walls of such an enlarged catch basin may help
to prevent contamination of the applicator by virtue of adherence
of the implant material to the surface area provided during
inversion or agitation of the applicator.
[0103] In the example shown in FIGS. 20 and 21, the introduction
section is provided with threads 32 which engage with threads (not
shown) on the interior of the second column 36, similar to the
arrangements provided in the embodiments shown in FIGS. 6-9. Handle
38 is provided for torquing the second column 36 with respect to
the first column 30. Accordingly, the concept of the introduction
section could be applied to any of those embodiments, and could
also be adapted to the embodiments having threading internally of
an introduction section with external threading on a second column.
The concept is also generally applicable to the embodiments shown
in FIGS. 13 and 14, where an introduction section could be provided
in the barrel 152 of the syringe.
[0104] FIG. 22 shows alternate configurations of an end of the
first column 30' and 30", and an independent funnel 54 useable with
each. The funnel or increased-size target region 54 may also be
integrated into the introduction section 24 to aid in pouring
implant material into the applicator. Drive threads may be placed
on the exterior funnel 54. A presently preferred thread size is
11/2-12 ACME 2.G 10.degree. external. However, when no integral
funnel is provided, a smaller introduction section 24',24" may be
used to provide a greater mechanical advantage. Additionally on the
smaller introduction section, or alternatively on the larger
introduction section, the drive threads placed exterior thereto may
be of a finer pitch or higher thread count than those previously
described to provide for greater mechanical advantage for
generating higher driving pressures more easily. To help in loading
material into the applicator when no integral funnel is used, a
separate funnel element 54 may be provided to interface with the
introduction section 24.
[0105] In the embodiments shown, the first column is advantageously
about 0.50 inches in diameter and of a length of about 4 inches in
order to provide sufficient volume for implant material for
efficiency in performing vertebroplasty and yet have a small enough
bore so that the mechanical advantage in applying pressure to the
implant material is not overly affected as would be the case with a
much larger bore. The preferred size range for the first column is
between about 0.375 to about 0.75 inches with a length of between
about 1.5 and 4.5 inches. The preferred capacitance of the first
column is at least 5 cc, up to about 15 cc, as described above.
[0106] Further details as to the use or other aspects of the
high-pressure implant system may be noted in the above referenced
applications already referred to in describing the present
invention which are herein incorporated by reference in their
entirety. It is noted that this invention has been described and
specific examples of the invention have been portrayed which may be
advantageous. The use of those specific examples is, however, not
intended to limit the invention in any way. Additionally, to the
extent that there are variations of the invention which are within
the spirit of the disclosure and yet are equivalent to the
inventions found in the claims, it is the intent that the claims
cover those variations as well. All equivalents are considered to
be within the scope of the claimed invention, even those which may
have not been set forth herein merely for the sake of brevity.
Also, the various aspects of the invention described herein may be
modified and/or used in combination with such other aspects also
described to be part of the invention or references discussed to
form other advantageous variations considered to be part of the
invention covered.
* * * * *