U.S. patent application number 10/549409 was filed with the patent office on 2006-11-23 for hydraulic device for the injection of bone cement in percutaneous vertebroplasty.
Invention is credited to Roque Humberto Ferreyro, Mario Marquez Miranda.
Application Number | 20060264967 10/549409 |
Document ID | / |
Family ID | 32986007 |
Filed Date | 2006-11-23 |
United States Patent
Application |
20060264967 |
Kind Code |
A1 |
Ferreyro; Roque Humberto ;
et al. |
November 23, 2006 |
Hydraulic device for the injection of bone cement in percutaneous
vertebroplasty
Abstract
The present invention relates to the medical field, in
particular relates to the practice of percutaneous vertebroplasty
where a pair of syringes in the distal extreme of a lengthened
hydraulic device, are united by a camera of intermediate connection
of larger diameter (pressure exerting body) or modified inverted
syringe tube with a bolster, a hydraulic connecting tube of
flexible material that transmits the pressure of the smaller
diameter manual or impulsion syringe in the proximal extreme of the
device toward the intermediate cylindrical larger diameter camera
(pressure exerting body), this camera is in an inverted position
with regard to the first syringe (fluid control), this intermediate
camera has a moving piston longitudinal to the axis of the cylinder
that is controlled with the first syringe (manual) and in
cooperation with the atmospheric pressure. The injecting syringe
loaded with bone cement is coupled with the bolster of the body of
pressure, and to the needle that drives the cement toward the
interior of the bone. The intermediate camera (pressure exerting
body) together with the hydraulic tube and the manual syringe form
a hydraulic press system (F/A=f/a) that allows to increase in a
potential way the pressure exerted in the first syringe and to make
the injection of polymethylmethacrylate (PMMA) at an approximate
distance of 1.0 m to 1.5 m.
Inventors: |
Ferreyro; Roque Humberto;
(Del. Alvaro Obregon, MX) ; Marquez Miranda; Mario;
(Oaxaca, MX) |
Correspondence
Address: |
WOLF, BLOCK, SCHORR & SOLIS-COHEN LLP
250 PARK AVENUE
NEW YORK
NY
10177
US
|
Family ID: |
32986007 |
Appl. No.: |
10/549409 |
Filed: |
March 14, 2003 |
PCT Filed: |
March 14, 2003 |
PCT NO: |
PCT/MX03/00027 |
371 Date: |
September 14, 2005 |
Current U.S.
Class: |
606/93 |
Current CPC
Class: |
A61B 17/8819 20130101;
A61M 5/31511 20130101; A61B 17/00234 20130101; A61M 5/31586
20130101; A61B 17/8822 20130101; A61F 2002/4635 20130101 |
Class at
Publication: |
606/093 |
International
Class: |
A61F 2/00 20060101
A61F002/00 |
Claims
1. Hydraulic device for injection of bone cement in percutaneous
vertebroplasty, that comprise four main parts, namely: injecting
syringe, pressure exerting body, hydraulic transmission tube, an
manual impulsion and fluid control syringe; the injection syringe
is a commercially available disposable 3 ml hypodermic syringe
placed next to the patient; the hydraulic tube for pressure
transmission, of 1.0 m to 1.5 m length, placed between the
injection syringe and the pressure exerting body; the manual
impulsion syringe placed after the hydraulic tube and near the
operator, characterized by the pressure exerting body consist of
hollow cylindrical body in the form of inverted syringe of larger
diameter with an adapted ending like an open bolster with the
largest external diameter and two diametrical opposed cuts like
oval entry, also in the other end one tip of reduced diameter; an
peripheral groove in the internal wall of such bolster, couples
tightly the wings of injection syringe in a revolved way; such
pressure exerting body has a movable piston on axial direction to
define two chambers, namely, internal and external.
2. Hydraulic device of injection of bone cement according to the
claim 1, characterized by the cylindrical hollow of pressure
exerting body (1), in form of an inverted positioned syringe that
renders mechanical advantage to the force exercised in the manual
syringe, it has a larger diameter and consists of a joining bolster
with internal peripheral groove where are coupled the wings of
injecting 3 ml syringe; a body cylindrical lengthened hole of 10 ml
of volume that contains a first free camera where the plunger (c)
of the injection syringe lodge inside the cylinder until coupled
with the moving internal piston (4), and a second internal camera
(5) occupied by a hydraulic fluid, this cameras are separated by
such piston (4) surrounded by a rubber cap that seals the internal
wall of the body of pressure and avoids leakage of the hydraulic
fluid; a final end tip of reduced diameter that is connected in a
hermetic way to the hydraulic tube (7).
3. Hydraulic device of injection of bone cement according to the
claim 2, characterized by the bolster is adapted to receive in a
first predetermined position of an oval entry (70) the wings of the
injection syringe, and in second position by a 90.degree. turn in a
peripheral groove (90), placed in a tight way.
4. Hydraulic device of injection of bone cement according to the
claim 1, characterized by the manual syringe (8) is a lengthened
syringe that has a smaller diameter than the pressure exerting body
in a 2/1, 3/1, 4/1 ratio, it is connected in continuation, far from
the application point by a hydraulic tube.
5. A method of operating the device for injection of bone cement
that comprises: to insert a bone biopsy needle in the place where
the bone cement is to be delivered; to connect the injecting
syringe, loaded with the cement, in continuation of the needle; to
couple in a revolved way, the injecting syringe in the internal
peripheral groove of the bolster of the pressure exerting body; to
exert pressure on the plunger of the injecting syringe by means of
the force exerted in the plunger of the manual syringe placed in
the other end of the hydraulic tube, this way, the content of the
injecting syringe is injected in the patient's vertebral body; to
retract the plunger of the manual syringe to withdraw the internal
piston of the body of pressure in position to receive a new loaded
cartridge of bone cement; to uncouple the injecting syringe from
the bolster of the body of pressure; to disconnect the empty
syringe from the needle placed in the patient's body; to couple the
new cartridge of bone cement (injecting syringe) in the needle and
bolster of the body of pressure, and repeat the previous steps to
place another new cartridge of bone cement, until completing the
filling of the vertebral body.
6. A device for delivering a viscous material into a site in a
patient, comprising: an actuator including an actuator vessel; a
delivery tube, having a first end, a second end and an inner bore,
wherein the first end is coupled to the actuator; and, a container
having a connection port for connecting to the second end of the
tube and an exit port.
7. The device of claim 6, wherein the actuator comprises a linear
actuator.
8. The device of claim 6, wherein the actuator comprises a
hydraulic pump.
9. The device of claim 6, wherein the actuator has a visualization
window for viewing the contents of the vessel.
10. The device of claim 9, wherein the visualization window has
means for measuring the amount of viscous material being
delivered.
11. The device of claim 10, wherein the means for measuring are
graduation lines marked on the outside of the actuator.
12. The device of claim 6, wherein the delivery tube is flexible
and noncompliant.
13. The device of claim 6, wherein the container is adapted to hold
at least 3 cc of viscous material.
14. The device of claim 6, wherein the container further comprises
a visualization window for viewing contents of the container.
15. The device of claim 14, wherein the visualization window has
means for measuring the amount of viscous material being
delivered.
16. The device of claim 15, wherein the means for measuring are
graduation lines marked on the outside of the container.
17. The device of claim 6, wherein the container is made from a
noncompliant material.
18. The device of claim 6, further comprising a substantially
incompressible fluid located within the vessel.
19. The device of claim 18, wherein the amount of fluid contained
in the vessel is greater than the amount of viscous material to be
delivered.
20. The device of claim 6, further comprising a cannula for
delivery of the viscous material to the site in the patient.
21. A device for delivering a viscous material comprising: a
delivery tube having a first end portion, a second end portion, and
an inner bore therebetween, the first end portion adapted to
contain an incompressible fluid and the second end portion adapted
to contain a viscous material.
22. The device of claim 21 further comprising: an actuator for
pressurizing the incompressible fluid.
23. The device of claim 22, wherein the actuator comprises a
hydraulic pump.
24. The device of claim 22, wherein the actuator has a
visualization window for viewing the fluid.
25. The device of claim 24, wherein the visualization window has
means for measuring the amount of viscous material being
delivered.
26. The device of claim 25, wherein the means for measuring are
gradient lines marked on the outside of the actuator.
27. The device of claim 21, wherein the delivery tube is flexible
and noncompliant.
28. The device of claim 21, further comprising a container
connected to the second end portion of the delivery tube.
29. The device of claim 28, wherein the container is adapted to
hold between 3 and 10 cc of viscous material.
30. The device of claim 28, wherein the container further comprises
a visualization window for viewing contents of the container.
31. The device of claim 30, wherein the visualization window has
means for measuring the amount of viscous material being
delivered.
32. The device of claim 31, wherein the means for measuring are
gradient lines marked on the outside of the container.
33. The device of claim 21, further comprising a substantially
incompressible fluid located within the reservoir.
34. The device of claim 33, wherein the amount of fluid contained
in the delivery tube is greater than the amount of viscous material
to be delivered.
35. The device of claim 21, further comprising a cannula for
delivery of the viscous material to the site in the patient.
36. The device of claim 21 further comprising: a separator sized to
move within the inner bore of the tube while separating the viscous
material from the incompressible fluid.
37. A method of delivering a viscous material under fluoroscopy to
a site in a patient comprising the steps of: a) providing a
delivery tube containing an incompressible fluid and a viscous
material, wherein the viscous material is located within the
fluoroscopy field; and b) pressurizing the incompressible fluid
outside the fluoroscopy field to exert pressure on the viscous
material.
38. The method of claim 37 wherein the delivery tube is flexible
and noncompliant.
39. The method of claim 37 wherein the step of pressurizing the
incompressible fluid, comprises using a linear actuator.
40. The method of claim 37 further comprising the step of: a)
determining the amount of viscous material delivered from a
visualization window.
41. A method of delivering a viscous material to a site in a
patient comprising the steps of: a) providing a device having an
actuator, a delivery tube filled with an incompressible fluid and a
container; b) filling the container with a viscous material; and c)
activating the actuator to pressurize the fluid to exert a force on
the viscous material.
42. A device for delivering a viscous material into a site in a
patient, comprising: a) a delivery tube, having a first end, a
second end and an inner bore, b) an incompressible fluid contained
within the inner bore of the delivery tube, c) a container having a
connection port for connecting to the second end of the delivery
tube, an inner bore, an exit port, d) a viscous material contained
within the inner bore of the container, and e) a separator sized to
move within the inner bore of the container for separating a
viscous material from the incompressible fluid.
43. A device for delivering a viscous material into a site in a
patient, comprising: a) a delivery tube, having a first end, a
second end and an inner bore, b) a first fluid contained within the
inner bore of the delivery tube, and c) a container having a
connection port for connecting to the second end of the delivery
tube, an inner bore, an exit port, and d) a second fluid contained
within the inner bore of the container.
44. A device for delivering a viscous material into a site in a
patient, comprising: a) a container having a connection port for
connecting to the second end of the delivery tube, an inner bore,
an exit port adapted for connection to the patient, b) a separator
housed within the inner bore, thereby defining a distal bore and an
proximal bore, c) a first fluid contained within the proximal bore
of the container.
45. The device of claim 44 further comprising: a) a second fluid
contained within the proximal bore of the container.
46. A device for delivering bone cement, comprising: at least one
delivery chamber filled with bone cement; and a hydraulic mechanism
coupled to said delivery chamber and adapted to advance said cement
out of said delivery chamber.
47. A device according to claim 46, wherein said hydraulic
mechanism utilizes a fluid other than said bone cement.
48. A device according to claim 46, wherein said bone cement is
polymethylmethacrylate.
49. A device according to claim 46, wherein said mechanism
comprises a flexible tube at least 100 cm long.
50. A device according to claim 46, wherein said hydraulic
mechanism provides hydraulic force amplification.
51. A device according to claim 46, wherein said hydraulic
mechanism provides force amplification by mechanical advantage.
52. A device according to claim 46, adapted to provide enough force
for a kyphoplasty procedure.
53. A method of hydraulic delivery of a viscous material into the
body, comprising: (a) providing a volume with bone cement therein;
and (b) increasing pressure in said volume using a hydraulic
mechanism with a working fluid other than said cement.
54. A method according to claim 53, wherein said viscous material
comprises bone cement.
55. A method according to claim 54, comprising increasing said
pressure using a flexible conduit.
56. A method according to claim 54, wherein said volume is enclosed
by a tube that enters the body.
57. A method according to claim 56, comprising coupling said tube
to said mechanism using a rotating connection.
58. A method according to claim 54, comprising delivering said
cement as part of a kyphoplasty procedure.
59. A method according to claim 54, comprising cooling said bone
cement in a manner sufficient to delay its solidification.
60. A method according to claim 54, comprising replacing a cement
chamber during a single medical procedure.
61. A method according to claim 54, comprising delivering 10 cc of
bone cement to a bone.
62. A method according to claim 54, comprising not replacing a
cement chamber during a single medical procedure.
63. A method according to claim 62, wherein said procedure is a
kyphoplasty procedure.
64. A method according to claim 62, wherein said procedure is a
vertebroplasty procedure.
65. A device for delivering bone cement, comprising: (a) a delivery
chamber including bone cement; and (b) a flexibly attached pressure
source adapted to increase a pressure in said delivery chamber.
66. A device according to claim 6, wherein said container contains
bone cement.
67. A device according to claim 7, wherein said viscous material
comprises bone cement.
68. A method according to claim 37, wherein said viscous material
comprises bone cement.
69. A method according to claim 41, wherein said viscous material
comprises bone cement.
70. A device for delivering viscous material, comprising: a tube
adapted to deliver a viscous material into a vertebra; and a
delivery system adapted to deliver said viscous material to said
tube and including a relatively long conduit connecting a power
application point and said tube.
71. A device according to claim 70, wherein said conduit is long
enough to reach out of an orthopedic x-ray viewing field.
72. A device according to claim 70, wherein said conduit is at
least 100 cm long.
73. A device according to claim 70, wherein said delivery system
comprises a cement reservoir.
74. A device according to claim 70, wherein said delivery system
includes a flexible coupling capable of being bent without
adversely affecting delivery of said viscous material.
75. A method of delivering viscous material, comprising: inserting
a tube having an axis into a vertebra; and attaching a delivery
system of viscous material to said tube; and applying power to
advance said viscous material into said vertebra, said power being
applied outside an x-ray viewing field being used for viewing said
vertebra and said power being applied in a manner which does not
trans-axially move said tube.
76. A method according to claim 75, wherein said attaching
comprises attaching using a flexible connection between said tube
and a point of application of said power.
77. A method of delivering viscous material, comprising: inserting
a tube into a vertebra; and selecting a force application angle
relative to an axis of said tube from a set of arbitrary angles;
attaching a delivery system of viscous material to said tube; and
applying a force to advance said viscous material into said
vertebra, said force being applied at said angle.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application the National Phase Application of
International Application No. PCT/MX2003/000027 filed Mar. 14,
2003.
TECHNICAL FIELD
[0002] This invention in a general way relates to the medical area
in procedures where it is required to inject a dense or viscous
fluid through a needle, in a particular way the viscous material is
the polymethylmethacrylate. It is used in procedures like
percutaneous vertebroplasty, kyphoplasty or other surgical events
of the field. It has applications in other areas where it is
required to apply at distance a dense and viscous liquid.
BACKGROUND OF THE INVENTION
[0003] Percutaneous vertebroplasty is a minimally invasive
interventional radiological procedure that consists on injecting
bone cement (Polymethylmethacrylate, PMMA) in the vertebral body,
by trans-pedicular or oblique approach through a bone biopsy
needle.
[0004] It was developed in France in 1984 for the treatment of
aggressive or painful haemangiomas of vertebral bodies. For its
analgesic effect, its use was quickly extended for the treatment of
lytic metastatic lesions or myeloma and mainly in fractures or
vertebral collapse due to osteoporosis. The procedure is indicated
in those cases that are presented with severe and disabling pain
that doesn't respond to conservative measures such as: corset use,
analgesic and anti-inflammatory treatment or bed rest.
[0005] Most of the patients with this suffering are between the 6th
and 8th decade of life. In this group of advanced age, the
immobilization resulting from vertebral fractures has severe
consequences in their general medical conditions, it predisposes
them to cardiopulmonary, intestinal, circulatory complications,
etc. Besides pain, the psychological effects can be devastating, it
deteriorates the quality and reduces the expectation of life.
[0006] Vertebroplasty is a procedure that is carried out in
hospital facilities that requires specialized medical personnel. It
is performed in a hemodinamia room or cath lab, and it requires of
the use of radiological equipment with high resolution fluoroscopy,
mounted in a C arm. Currently, this injection is carried out in a
manual and direct way and the operator is exposed to ionizing
radiation every time that he/she practices a vertebroplasty. The
injection of bone cement is made with fluoroscopic control,
connecting an insulin syringe to the needle. This implies that the
surgeon is in direct contact with the patient and therefore,
overexposed to primary or secondary ionizing radiation during the
lapse of the procedure of the vertebroplasty.
[0007] The primary radiation is the X ray beam coming from the X
ray tube and received by the patient in a direct way, The secondary
radiation it the one resulting on the deviation of the primary beam
in the patient's body tissues and doesn't contribute to the
formation of a diagnostic image, it is spread in all directions and
it is the main source of exposure of medical personnel.
[0008] The insulin syringe is used since a small diameter barrel is
required to have less resistance for the manual injection of high
viscosity bone cement, each syringe is filled approximately in half
or two thirds of its capacity to avoid bending or breaking the
plunger when exercising the required injecting pressure that may be
considerable. The volume needed to obtain the expected results
varies from 3 ml up to 9 ml, therefore, 5 to 18 syringe exchanges
are necessary, this favors the solidification of the
polymethylmethacrylate and it can prevent to inject the wanted
quantity.
[0009] If larger diameter syringes are used, the manual pressure is
insufficient due to the density and viscosity of the bone cement;
and becomes necessary the employment of a mechanical device to be
able to exercise the required pressure. At the state of the art,
there are commercially available devices such as pressure gun type
or threaded plunger mechanisms connected directly to the needle
that deposits the cement in the bone or through a high pressure
short tube. The use of a long tube would have considerable
resistance to the flow of the cement, favoring its
solidification.
[0010] In most of these devices the syringe is not interchangeable,
it is loaded with the total volume to inject and therefore, are of
larger diameter and the increased resistance to the flow of the
cement becomes worse with time due to solidification of cement.
[0011] On the other hand, the conventional hypodermic syringes are
not designed for high pressure injection, the plunger and the
fingers supporting wings bend easily.
[0012] The devices of the previous technique solve only the
mechanical problem of injecting the dense and viscous cement
through the needle but they are focused on exercising the necessary
pressure directly on the patient or at a very short distance of the
radiation source. They don't allow the operator to maintain an
appropriate distance to reduced exposure to secondary radiation at
acceptable levels according with the international radiological
protection norms.
[0013] On the other hand, some mechanical devices do not allow
control or manual sensibility of the exercised pressure and speed
of the injection of the cement, important factors in the prevention
of undesirable leaks and complications. Some devices that apply
cement in the current state of the art are for example:
[0014] The patent application of the United States of America No.
2003/0018339, for Higueras et al, published Jan. 23th of 2003, it
discloses an application device for the controlled injection of
bone cement, mounted in a syringe loaded with the cement, as a
cartridge, which is discharged by a threaded metallic plunger
placed in the other end of the device, it is useful for controlling
the pressure exercised on the plunger of the syringe but it is a
short device in which the operator is near the patient; It also
contains the total load of cement.
[0015] On the other hand, due to the viscosity of the cement and
quantity keeps certain dynamic memory that doesn't allow sudden
interruption of the injection.
[0016] The patent application of the United States of America No.
2002/0156483, for Voellmicke et al, published Oct. 24th of 2002,
discloses a vertebroplasty device and bone cement, it contains two
compartments, one for mixture of the cement and the other for
storage and injection into the bone. This dual camera device for
blending and injection, consists of a lodging camera with a plunger
moving in an axial way, the cameras are in communication by a check
valve that only allows the passage of the cement in one direction.
An extra force can be exercise on the plunger by means of a lever
that increases the mechanical force and therefore the pressure in
the injection camera. This is a device in which it is necessary to
work the piston of the blending camera and the piston of the
injection camera to empty one and fill the other one alternatively.
It is a short device, it is necessary to be near the patient and
doesn't reduce the exposure to secondary ionizing radiation.
[0017] The patent application of the United States of America No.
2002/0099384, for Scribner et al, published Jul. 25th of 2002,
discloses a system and method to treat vertebral bodies. It is a
special syringe with two concentric plungers. The first camera that
has a first transverse section and a second smaller camera than the
first one. Both cameras communicate to each other. The first camera
includes a gate to receive the material inside the filling
instrument, the second camera includes a gate to discharge the
contained material. A first plunger suited to pass through the
first camera and displace the material. A second plunger to pass
through the interior of the first plunger's concentric hole and
reach the interior of the second camera to displace the material
through the exit in the second camera to inject into the needle
toward the interior of the vertebral body. Although this device
provides control in the injection of the bone cement, the operator
is too near the patient.
[0018] In general the injection devices have a bolster that impels
the viscous fluid by means of a manual trigger moved by a screw
mechanism (inclined plane), there are others that have a gun like
body such as the device of the Patent Application of the United
States of America. 2002/0049448, for Sand et al, published Apr.
25th, 2002, It has a tubular body that stores a viscous flowing
material (bone cement), it is a longitudinal body with a providing
end and a driving end, a plunger housed inside the tubular body
that displaces the flowing material along the longitudinal axis of
the tubular body, the driving mechanism has a handle like a gun to
hold with a hand, while injecting with the other hand by means of
the plunger that advances due the pressure exerted by a threaded
mechanism. These mechanisms with big deposits have the
inconvenience that the cement can end up solidifying in the conduit
at the time of application and impede to apply the total amount of
cement inside the affected vertebral body. On the other hand, with
the excess of pressure generated by these devices, the cement could
leak outside of the vertebral body, since the fluid (PMMA), for its
viscosity, possesses a remaining flowing memory that may be
difficult to control.
[0019] The Patent of the United States of America U.S. Pat. No.
6,348,055, for Preissman, published Feb. 19th of 2002, protects a
bone cement applying device with screw mechanism in which the
preparation of the total volume of cement is made, this mechanism
has an intermediate stabilizer that avoids the turns of the whole
device during the application of pressure to the fluid. The
stabilizer is a lever perpendicular to the screw body that can be
sustain with a hand, while with the other hand exercises the
pressure to inject the cement inside the vertebral body. This
device is also operated very near the patient and therefore, the
operator is exposed to secondary ionizing radiation. Another
inconvenience is that if the cement solidifies in the system and
has not reached the vertebral body in the proper amount, it is
necessary to make another preparation previous placement of another
needle in a different and appropriate position for the new
requirement.
[0020] The Patent Application of the United States of America No.
2002/0010431, for Dixon et al, published Jan. 24th, 2002, discloses
a screw device for high pressure with a threaded axis that impels a
plunger inside a camera full with viscous bone cement. This device
has the inconvenience that one doesn't have manual sensitivity and
control of the pressure exercised, it is not easy to exchange the
syringes with the bone cement. As a matter of fact, it is the only
syringe of the cartridge.
BRIEF SUMMARY OF THE INVENTION
[0021] Among the several objects of the present invention, a better
control of the pressure in the placement of bone cement or other
viscous materials in the bone is provided. The invention
facilitates the injection of viscous filler in trabecular bone or a
cavity formed in the vertebral body.
[0022] Another object of the present invention it is to provide a
hydraulic device to treat vertebral fractures and reduce the pain,
stabilize the vertebral body, to obtain higher resistance to
compression, avoid further collapse and at the same time, to allow
early mobilization of the patients and improve their quality of
life.
[0023] It is still another object of the present invention, to
provide a device for the injection of viscous material in the
vertebral body that allows the operator to keep and appropriate
distance (1.0 m to 1.5 m) in order to reduce exposure to ionizing
radiation at acceptable levels within the international norms.
[0024] It is also another object of the present invention, to
provide a hydraulic press like device using syringes of unequal
caliber (3 and 10 ml) to exercise hydraulic pressure at distance
transmitted from a proximal, manual syringe of smaller caliber,
through the polyethylene tube until the distal or injecting
syringe.
[0025] It is another object of the present invention to provide a
cylinder of pressure with mechanical advantage complementary to an
hydraulic system of syringes for injection at distance of
polymethylmethacrylate suspension in the cancellous bone of a
vertebral body. This way, the overexposure of the operator to
ionizing radiation is reduced.
[0026] It is still another object of the present invention to
provide a hollow cylinder or body of pressure in the shape of an
inverted syringe to form a hydraulic device that allows manual
control on the volume and velocity of injection
polymethylmethacrylate (PMMA) and also immediate interruption of
the pressure applied on the fluid.
[0027] It is still an object of the present invention, to provide a
device that prevents the movements or abnormal displacements of the
needle during the injection and syringes exchange (1 or 2 exchanges
may be necessary), it reduces time loss and allows to maintain the
bone cement loaded syringes in a recipient or cold atmosphere to
slow time of solidification.
[0028] It is another object of the present invention, to provide a
device that uses syringes from 3 to 5 ml that require smaller
injection pressure, and can be exchanged easily with a single
90.degree. rotation movement, Hub Lock type.
[0029] It is still an object of the present invention, to provide a
device for injection of viscous material that can be manufactured
of plastic, aluminum or any other disposable light-weighted
material for single use or suitable for re-sterilization, sturdy
enough to support the pressure of injection.
[0030] It is another object of the present invention to provide a
flexible hydraulic, light-weighted device that prevents the
movements or unwanted displacements of the needle during the
injection.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] The FIG. 1, represents the connection outline of the novel
hydraulic press like device for injection at distance, of the
present invention.
[0032] The FIG. 2, represents an injection device with a screw type
threaded plunger of the previous technique.
[0033] The FIG. 3, represents a device of injection of the previous
technique, which has a recipient to make the mixture, another to
exercise the injecting pressure. each recipient contains a check
valve in their exit holes to avoid re-flow
[0034] The FIG. 4, represents a device of injection of the previous
technique, which contains a larger capacity syringe in which the
total amount of bone cement mixture is placed to inject, impelled
by a threaded plunger.
[0035] The FIG. 5 represents the device object of the present
invention corresponding to the transverse view of the piston
together with the rubber cap.
[0036] The FIG. 6 represents the smaller, manual syringe for
control of the device with the plunger and rubber cap.
[0037] The FIG. 7, it represents the syringe of force, the conduit
(7) that transmits the pressure to the larger diameter device (B)
and the way to place the plunger (A) of the injecting syringe that
contains the material and the injection needle.
[0038] The FIG. 8, represents a hydraulic press, theoretical basic
principles of the present invention.
[0039] The FIG. 9, represents the pressure transmitted in the tube
and the exit force generated, which pushes the plunger that injects
the material through the needle.
DETAILED DESCRIPTION OF THE INVENTION
[0040] The present describes a new device and method to treat
affections of the bones, specifically, in the treatment of
osteoporotic or fractured vertebral bodies.
[0041] These bone structures have different pathological states of
diverse ethiology (trauma, osteoporosis, primary bone tumors or
metastasys, etc.). An alternative of treatment to stabilize and to
consolidate this structures consists on the injection of a
bio-materials such polymethylmethacrylate in the interior of the
vertebral body for healing purpose.
[0042] The injection of biomaterials such as bone cement is carried
out by means of a hydraulic device exerting pressure on small
caliber conventional syringes connected directly to the needle;
since the cement has the property of becoming hard quickly.
[0043] The theoretical basic principle for the operation of the
device of the present invention consists on the amplification of
the hydraulic pressure generated at distance and transmitted by the
hydraulic tube.
[0044] In reference to the FIG. 8, the most frequent application to
the Law of Pascal is the hydraulic press that consists of two
asymmetric columns of liquid. This principle is applied in
mechanical devices of engineering areas, this columns are different
in the size or diameter of the transverse section. In accordance
with the Law of Pascal, a pressure applied in one of the columns is
transmitted entirely and in all directions. Therefore, if a force
F.sub.1 is applied on the area piston A.sub.1, it will cause an
exit force F.sub.0 that acts on an area A.sub.0 of the piston. This
way, the entrance pressure is the same to the exit pressure, that
is to say: F.sub.1/A.sub.1=F.sub.0/A.sub.0
[0045] The ideal mechanical advantage of the device is similar to
the relationship of the exit force with regard to the entrance
force. VM=F.sub.0/F.sub.1=A.sub.0/A.sub.1
[0046] Where a small entrance force can be multiplied
(A.sub.0/A.sub.1 times) to produce a larger exit force (F.sub.0),
using an exit piston with a larger area than that of the entrance
piston. The exit force will be given by:
F.sub.0=F.sub.1A.sub.0/A.sub.1
[0047] If friction is disregarded, in an ideal situation the
entrance work should be the same to the exit work. Therefore, if
the force F.sub.1 travels a distance S.sub.1 while the exit force
F.sub.0 travels a distance S.sub.0, there is equality.
F.sub.1S.sub.1=F.sub.0S.sub.0
[0048] The mechanical advantage can be expressed in terms of the
distances traveled by the pistons:
VM=F.sub.0/F.sub.1=S.sub.1/S.sub.0
[0049] It is observed that the mechanical advantage is obtained at
expenses of the distance that the entrance piston travels.
[0050] In reference to the FIG. 9 that describes the body (B) and
area (95) of the piston of larger area of the present invention, it
is also represented the entrance of the pressure P.sub.1 that is
transmitted through the incompressible fluid, either water or oil,
content in the flexible tube (not shown) that generates an exit
force F.sub.0. The attachment (2) for the lateral wings of the
injecting syringe that contains the bone cement acts as coupler to
the device, the wings enter tightly in the internal peripheral
groove (70) diametrically opposed inside the bolster (header) of
the body of the device object of the present invention, with a turn
of 90.degree. either clockwise or counterclockwise. The plunger of
the syringe enters in the longitudinal central space (95) of the
body (B).
[0051] Returning to the FIG. 1, the hydraulic device consists of
four main parts arranged one after another in such a way that
allows to inject at distance and in a controlled way (regarding the
pressure) viscous materials such as polymehylmethacrylate used in
percutaneous vertebroplasty for the reestablishment (without
surgery) of patient with osteoporotic fractures.
[0052] The device here described is designed to inject at distance
a polymethylmethacrylate suspension with viscous consistency,
directly in the cancellous bone of the vertebral bodies by means of
a syringe loaded with the bone cement attached to a bone biopsy
needle. The device consists of four main parts, "injecting syringe"
in vicinity to the patient, "pressure" exerting body, "hydraulic
transmission tube" and "manual syringe". In this, the fingers of
the operator exercise the controlled force. This control is carried
out by the operator's tact sensitivity. This device conforms a
hydraulic system for polymethylmethacrylate injection at a variable
distance from the patient (usually 1 m to 1.5 m).
[0053] The injection part is a commercially available, disposable 3
ml. hypodermic syringe (a) that is placed next to the patient,
loaded with the bone cement that consists of a plunger (11) that
pushes the material (CO) to be injected in the vertebral body
trough a bone needle (CA), (not shown). This syringe couples
tightly in a revolved way, by means of the opposed wings of support
(b), in a peripheral groove in the internal face of the bolster (2)
of the body of pressure, it is coupled by means of the opposed
wings (b) used as support for the fingers in an act of usual
injection, these wings (b) are placed in the entrance guide and
rotated, either clockwise or counterclockwise an angle of
90.degree. to stay in tightly fixed to avoid inadvertent detachment
and loss of the pressure. The injection needle is coupled rotating
the threaded distal end (CA) in the usual way of common plastic
syringes in order to avoid spillage of the material to be injected
due to the high pressure exercised on the plunger (c) and its end
(3). For exchange, the empty syringe is detached from the needle,
and then from the pressure device by means of a 90.degree.
rotation, discarded (2) and replaced with another loaded syringe
prepared in advance and stored in a cold environment to delay
curing and hardening of the cement. The syringe (a) is of 3 or 5 ml
capacity.
[0054] The part of pressure, consists of distal inverted syringe
body (1) of larger diameter that the syringe at the proximal end of
the complete device, It has a bolster (2) open to the atmospheric
pressure that contains an internal peripheral groove where the
opposed supporting wings of the injecting disposable hypodermic
syringe are coupled (b) with a turn of 90.degree.. Its interior is
open to the atmospheric pressure and receives the plunger of the
injecting syringe (c) in a extended position to make contact with
the rigid surface of the piston (3), The piston moves tightly with
respect of the internal wall of the device (1) by means of a rubber
cap (4), to maintain a closed hydraulic space (5) The distal
pressure is transmitted to the piston through the opening or
mouthpiece (6) connected to the flexible tube of polyethylene or
similar material (7) by means of the hydraulic fluid (10). The
rigid surface of the piston (3) exercises pressure (which has been
increased by the device) on the plunger (1) of the injecting
syringe. The body (1) is manufactured of transparent plastic,
aluminum or any other suitable light-weighted and rigid material.
Other characteristics of the body will be described (1) with more
detail in the FIGS. 5, 7 and 9.
[0055] The hydraulic tube for pressure transmission (the Pascal's
Principle), is a tube or flexible hose of polyethylene or similar
material of little weight, with appropriate diameter to couple in
the distant and proximal ends of the syringes, the longitude is
variable, most commonly of 1.0 m to 1.50 m, it is resistant to the
internal pressure. The tube is loaded of water, oil or other
non-compress fluid (10) to integrate together with the manual
proximal syringe and the body of pressure closed hydraulic
system.
[0056] The manual syringe (8), has a smaller diameter than the body
of pressure (1) in a 2/1, 3/1 or 4/1 ratio that may vary according
to the necessity of each case. According to the hydraulic press
described in the FIG. 8, the longitude of the manual syringe should
be larger than that of the body of pressure (1) with the purpose of
containing enough volume to displace the piston the distance
required to impel the plunger of the injecting syringe. this way,
the quantity required of bone cement is deposited in the vertebral
body.
[0057] The device works in the following way: a manual force is
exercised on the plunger (9) of the manual syringe (8) in its
extended position, the force exercises a pressure that is
transmitted through the incompressible fluid (10) content in the
flexible tube and in the camera (5) of the body of pressure (1).
This pressure exercises an increased force on the plunger of the
injecting syringe, due to the mechanical advantage of the
relationship of areas or displacements formerly described. The
plunger of the injecting syringe in turn, exert a force that impels
(to) the material or cement to be injected in the patient's
vertebral body through the bone biopsy needle. Once the total
amount or content of the injecting syringe has been delivered, the
plunger of the manual syringe is retracted to generate space inside
the body of pressure (1) by retracting the piston to replace the
emptied syringe with a loaded new syringe to continue the
injection. Up to 10 ml. of bone cement is required to achieve an
suitable filling of the fractured vertebral body, therefore, 3 to 4
syringe exchanges may be necessary.
[0058] The bone needle stays in place during the procedure that is
to say, the movements or abnormal displacements of the needle
during the injection are avoided, situation that implies several
advantages: For the patient, since additional punctures are less
frequent and for the operator with less problems of solidification
of the cement.
[0059] Another advantage of the device is that the transmission of
the pressure is immediate, that is to say, doesn't have a dynamic
memory by effects of the increasing viscosity due to the
solidification in the injection conduit specially with prolonged
injections, prone to happen in the injecting devices of the
previous technique that are loaded with the complete volume of
cement to be placed. On the other hand, the threaded plunger
doesn't allow tact sensibility regarding the exercised pressure and
therefore favors unwanted leakage of the bone cement due to the
dynamic memory of the material.
[0060] To this respect we have devices of the previous technique
such as the (20) FIG. 2 that consists of a threaded plunger (23)
that impels the contained cement in the camera (24) and a refilling
deposit (22) that in turn feeds the camera by means of a plunger
(21); A handle (25) that serves for support to the other hand of
the operator to facilitate exercise the intense force so that the
cement flows in a short tube (26) and it is injected through the
needle (27).
[0061] The device (30) of the previous technique of the FIG. 3
contains two cameras (35) (32) connected by a valve check in the
conduit (37). The bone cement is mixed In the camera (35) and
impelled to the injection camera (32) by means of a plunger (36),
once in the injection camera the cement is impelled by the piston
(38) of a plunger (34) moved by a lever that provides the required
force (33), forcing the cement through the opening (31) that in
turn contains a valve check that closes in the recharge
operation.
[0062] The FIG. 4 illustrate another device (40) of the previous
technique for injection of polymethylmethacrylate. In this one the
threaded plunger (41) has a crank (42) in the end to facilitate
impel the total content of the syringe (45), and supporting
elements (43) (44) for the other hand of the operator in the action
of injection of the bone cement.
[0063] The FIG. 5, represents a cut profile and front view the body
of pressure (50) that shows the groove of the bolster (2) where the
injecting syringe that contains the bone cement is secured. Also
presents the front view and profile of the piston (51) and the
rubber cap (52) that avoids spillage of the hydraulic fluid in the
action of transmission of the pressure. With this body of pressure,
object of the present invention, is possible to transmit the
pressure at distance and therefore reduces exposure of the operator
to secondary ionizing radiation coming from the patient at the time
of placement of the bone cement. This body of pressure complies
with the characteristic of being light-weighted, may be disposable
or reusable, manufactured of plastic, aluminum or other suitable
material able to support sterilization.
[0064] The FIG. 6, represents frontal and lateral views of the
manual or impulsion syringe (60), and plunger (61) where the rubber
cap is placed (62) to avoid leakage of the hydraulic fluid. The
bone cement should be kept in a cold environment before it is
applied so it is maintain fluid to avoid solidification in the
needle.
[0065] In the FIG. 7, the transverse cut of the cylindrical hollow
body of pressure is described (B) that houses the plunger (A) of
the injecting syringe secured in the peripheral groove (70) of this
body of pressure, it is connected to the flexible tube (7) that
transmits the hydraulic pressure (10), exercised from the manual or
impulsion syringe (C) by means of its plunger (9). Here is
illustrated the way the injecting syringe is attached to the body
of pressure, Once introduced the plunger (A) in the opening of the
body of pressure (B) the syringe is turned 90.degree. in such a way
that the body of the syringe is tightly secured to proceed with the
injection of the bone cement.
[0066] The use of small diameter syringes in the application of the
cement has the advantage of less resistance to flow, so a more
viscous cement can be injected to reduce the possibilities of
leakage from the vertebral body.
[0067] The experts in the technique expect other embodiments of the
invention might exist, that is to say, embodiments of instruments
built according to the teachings of the present invention. Because
many of the characteristics of the embodiments are similar to those
previously described. Peculiar embodiments of the invention have
been illustrated and described in those that it will be obvious for
those experts in the technique that several modifications or
changes can be made without leaving the reach of the present
invention. The above-mentioned tries to cover with the added claims
so that the changes and modifications fall inside the reach of the
present invention.
* * * * *