U.S. patent application number 14/716248 was filed with the patent office on 2015-11-12 for cement delivering device and method.
The applicant listed for this patent is Kyphon Sarl. Invention is credited to Bryan Click, Brian Donovan.
Application Number | 20150320470 14/716248 |
Document ID | / |
Family ID | 49477928 |
Filed Date | 2015-11-12 |
United States Patent
Application |
20150320470 |
Kind Code |
A1 |
Click; Bryan ; et
al. |
November 12, 2015 |
CEMENT DELIVERING DEVICE AND METHOD
Abstract
A delivery system includes a reservoir for storing pressurized
fluid and a piston rod passing through the reservoir and having an
end portion with a dimension larger than the piston rod. A sleeve
is configured to engage the end portion of the piston rod such that
when the piston rod is advanced, the end portion seals an opening
in the sleeve. The sleeve and the end portion function as a piston
for extracting fluid from a delivery chamber. When the piston rod
is retracted, the sleeve engages a portion of the end portion to
permit the reservoir to communicate with the delivery chamber
through the opening. Methods of use are disclosed.
Inventors: |
Click; Bryan; (Fremont,
CA) ; Donovan; Brian; (San Jose, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kyphon Sarl |
Neuchatel |
|
CH |
|
|
Family ID: |
49477928 |
Appl. No.: |
14/716248 |
Filed: |
May 19, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13456597 |
Apr 26, 2012 |
9095394 |
|
|
14716248 |
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Current U.S.
Class: |
606/94 |
Current CPC
Class: |
A61M 5/315 20130101;
A61B 17/8805 20130101; A61M 5/2053 20130101; A61B 17/8822 20130101;
A61M 2202/0007 20130101; A61M 5/31515 20130101; A61B 17/8802
20130101; A61B 17/8827 20130101 |
International
Class: |
A61B 17/88 20060101
A61B017/88; A61M 5/315 20060101 A61M005/315; A61M 5/20 20060101
A61M005/20 |
Claims
1-20. (canceled)
21. A delivery system, comprising: a housing comprising a proximal
end defining a reservoir for storing fluid and a distal end
comprising a nozzle defining a chamber; a sleeve movably positioned
within the nozzle and comprising an opening; and a piston rod
having an end portion positioned within the sleeve such that the
end portion seals the opening off from the chamber, wherein the
system is movable between a first mode in which the piston rod is
moved proximally relative to the housing to space the end portion
apart from the opening such that the fluid moves from the reservoir
and into the chamber through the opening and a second mode in which
the piston rod is moved distally relative to the housing such that
the sleeve moves relative to the housing to eject the fluid from
the chamber.
22. The delivery system recited in claim 21, wherein a proximal
portion of the piston rod extends through the fluid when the fluid
is stored in the reservoir.
23. The delivery system recited in claim 21, wherein the opening
has a circular cross sectional configuration and the end portion
has a spherical shape that forms an interference fit with the
opening to seal the opening off from the chamber.
24. The delivery system recited in claim 21, wherein the end
portion includes a ball shape configured to engage the opening in
the sleeve to form a valve, the valve being opened when the system
is in the first mode, and the valve being closed when the system is
in the second mode.
25. The delivery system recited in claim 21, further comprising a
biased reservoir piston configured to pressurize the fluid stored
within the reservoir.
26. The delivery system recited in claim 25, wherein the biased
reservoir piston is biased by a spring disposed within the housing,
the spring being fixed to a proximal end of the housing.
27. The delivery system recited in claim 21, wherein the sleeve
comprises a second opening positioned proximal to the opening, the
opening and the second opening each having a maximum width that is
less than that of the end portion such that the end portion is
positioned between the opening and the second opening when the
system is in the first mode and when the system is in the second
mode and the end portion is retained within the sleeve.
28. The delivery system recited in claim 21, wherein the sleeve
includes at least two opposing supports that are configured to
maintain the end portion within the sleeve when the system is in
the first mode.
29. The delivery system recited in claim 21, further comprising the
fluid, wherein the fluid comprises poly(methyl methacrylate).
30. The delivery system recited in claim 21, wherein a dispensing
pressure for the fluid is achieved only in the chamber.
31. The delivery system recited in claim 21, wherein pressure
within the chamber is greater than pressure within the reservoir
when the system is in the second mode.
32. The delivery system recited in claim 21, wherein the piston rod
is reciprocated to move the system between the first mode and the
second mode to alternately fill and dispense the fluid from the
chamber.
33. A method for delivering bone cement comprising: providing the
delivery system recited in claim 21; moving the system to the first
mode to fill the chamber with the fluid; and moving the system from
the first mode to the second mode to eject the fluid from the
chamber.
34. A method for delivering bone cement as recited in claim 33,
wherein the system is moved between the first mode and the second
mode by reciprocating the piston rod.
35. A delivery system, comprising: bone cement; a housing
comprising a proximal end defining a reservoir for storing the bone
cement and a distal end comprising a nozzle defining a chamber; a
sleeve movably positioned within the nozzle and comprising an
opening; and a piston rod having a proximal portion that extends
through the bone cement and an end portion positioned within the
sleeve such that the end portion seals the opening off from the
chamber, wherein the system is movable between a first mode in
which the piston rod is moved proximally relative to the housing to
space the end portion apart from the opening such that the bone
cement moves from the reservoir and into the chamber through the
opening and a second mode in which the piston rod is moved distally
relative to the housing such that the sleeve moves relative to the
housing to eject the bone cement from the chamber.
36. The delivery system recited in claim 35, wherein the sleeve
comprises a second opening positioned proximal to the opening, the
opening and the second opening each having a maximum width that is
less than that of the end portion such that the end portion is
positioned between the opening and the second opening when the
system is in the first mode and when the system is in the second
mode and the end portion is retained within the sleeve.
37. The delivery system recited in claim 35, wherein the sleeve
includes at least two opposing supports that are configured to
maintain the end portion within the sleeve when the system is in
the first mode.
38. The delivery system recited in claim 35, wherein the opening
has a circular cross sectional configuration and the end portion
has a spherical shape that forms an interference fit with the
opening to seal the opening off from the chamber.
39. The delivery system recited in claim 35, wherein the end
portion includes a ball shape configured to engage the opening in
the sleeve to form a valve, the valve being opened when the system
is in the first mode, and the valve being closed when the system is
in the second mode.
40. A delivery system, comprising: bone cement; a housing
comprising a proximal end defining a reservoir for storing the bone
cement and a distal end comprising a nozzle defining a chamber; a
biased reservoir piston configured to pressurize the bone cement,
the biased reservoir piston being biased by a spring disposed
within the housing, the spring being fixed to a proximal end of the
housing; a sleeve movably positioned within the nozzle and
comprising an opening; and a piston rod having a proximal portion
that extends through the bone cement and an end portion positioned
within the sleeve such that the end portion seals the opening off
from the chamber, wherein the system is movable between a first
mode in which the piston rod is moved proximally relative to the
housing to space the end portion apart from the opening such that
the bone cement moves from the reservoir and into the chamber
through the opening and a second mode in which the piston rod is
moved distally relative to the housing such that the sleeve moves
relative to the housing to eject the bone cement from the chamber.
Description
[0001] This application is a continuation of U.S. patent
application Ser. No. 13/456,597, filed on Apr. 26, 2012, which is
expressly incorporated herein by reference, in its entirety.
TECHNICAL FIELD
[0002] The present disclosure generally relates to medical devices
for the treatment of musculoskeletal disorders, and more
particularly to a surgical system and method for delivering cement
or other materials.
BACKGROUND
[0003] Many medical procedures employ medical grade cement in
connection with the restoration and strengthening of bone
structures. During such procedures, cement is typically dispensed
to a bone to fill in voids or spaces in the bone or between medical
devices or implants attached to or embedded within the bone. These
dispensing devices may include systems as simple as syringes and as
complex as electronically controlled values.
[0004] Due to the medical nature of some procedures, the amount and
placement of the fluids, such as, cement, needs to be supervised
carefully. Despite the simplicity or complexity of the dispensing
system, control over when, where and how much cement is dispensed
is of concern. This disclosure describes improvements over these
prior art technologies in providing better control for dispensing
fluids, in particular, with respect to applications where greater
valve control is needed.
SUMMARY
[0005] Accordingly, a surgical system and method for delivering
fluid, such as cement to a bone are provided. In one embodiment, in
accordance with the principles of the present disclosure, a
delivery system is provided. The system comprises a reservoir for
storing pressurized fluid and a piston rod passing through the
reservoir and having an end portion with a dimension larger than
the piston rod. A sleeve is configured to engage the end portion of
the piston rod such that when the piston rod is advanced, the end
portion seals an opening in the sleeve. The sleeve and the end
portion function as a piston for ejecting fluid from a delivery
chamber. When the piston rod is retracted, the sleeve engages a
portion of the end portion to permit the reservoir to communicate
with the delivery chamber through the opening.
[0006] In one embodiment, the system comprises a delivery system,
including a reservoir for storing pressurized fluid and a biased
reservoir piston configured to pressurize fluid in the reservoir.
The reservoir piston is biased by a spring disposed within a body
in fluid communication with the reservoir. A piston rod passes
through the reservoir and has a ball-shaped end portion with a
dimension larger than the piston rod. A sleeve is configured to
engage the end portion of the piston rod. The sleeve includes an
outer portion that contacts an internal bore of a delivery chamber,
at least two opposing supports that are configured to engage the
end portion of the piston rod and an engagement portion on each
support being configured to occupy a fraction of a surface area of
the end portion of the piston rod. When the piston rod is advanced,
the end portion seals an opening in the sleeve, and the sleeve and
the end portion function as a piston for ejecting fluid from the
delivery chamber. When the piston rod is retracted, the sleeve
engages a portion of the end portion to permit the reservoir to
communicate with the delivery chamber through the opening and force
fluid into the delivery chamber.
[0007] In one embodiment, a method for delivering bone cement
includes the steps of: providing a delivery system including a
reservoir for storing pressurized fluid, a piston rod passing
through the reservoir and having an end portion with a dimension
larger than the piston rod, and a sleeve configured to engage the
end portion of the piston rod such that when the piston rod is
advanced, the end portion seals an opening in the sleeve, and the
sleeve and the end portion function as a piston for ejecting fluid
from a delivery chamber, and when the piston rod is retracted, the
sleeve engages a portion of the end portion to permit the reservoir
to communicate with the delivery chamber through the opening, and
reciprocating the piston rod to alternately fill and dispense fluid
from the delivery chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The present disclosure will become more readily apparent
from the specific description accompanied by the following
drawings, in which:
[0009] FIG. 1 is a side view of one embodiment of a delivery system
with some parts in phantom to show internal components in
accordance with the principles of the present disclosure;
[0010] FIG. 2 is a magnified view of the components of the system
shown in FIG. 1 showing details of a piston assembly formed with an
end portion of a piston rod and a sleeve in accordance with the
present principles;
[0011] FIG. 3 is a perspective view of the end portion of the
piston rod and the sleeve when the piston rod is retracted to
enable a delivery chamber to be filled in accordance with the
present principles; and
[0012] FIG. 4 is a perspective view of the end portion of the
piston rod and the sleeve when the piston rod is advanced to seal
off the delivery chamber and form a piston assembly for evacuating
the delivery chamber in accordance with the present principles;
[0013] Like reference numerals indicate similar parts throughout
the figures.
DETAILED DESCRIPTION
[0014] The exemplary embodiments of a surgical system and related
methods of use disclosed are discussed in terms of medical devices
for the treatment of musculoskeletal disorders and more
particularly, in terms of a surgical system and method for
delivering cement or other materials during a procedure. It is
envisioned that the surgical system and method may be employed in
applications such as repairing cracks, fissures, fractures, etc.
rebuilding bone or securing prosthetic joints, pins, or other
devices in bones.
[0015] In one embodiment, the surgical system provides a cement
delivery device that delivers cement or other material from a
single reservoir while limiting a high-pressure region to a small
diameter delivery chamber. A reciprocating piston may be
mechanically actuated from outside of a fluoroscopy field. During a
delivery stroke, a piston with a ball end seals against a sleeve
and is driven to deliver cement. As the piston and sleeve are
retracted, a valve opens and cement is forced from a main reservoir
into the delivery chamber. Driving a smaller diameter section of
cement reduces a force necessary to generate delivery pressures,
allowing for a wider range of actuation mechanisms. Limiting the
high-pressure regions of the device contributes to overall safety
and manufacturability. A positive displacement fill minimizes
lag-time between actuations and permits for partial strokes.
[0016] It is contemplated that one or all of the components of the
surgical system may be disposable, peel-pack, pre-packed sterile
devices. One or all of the components of the surgical system may be
reusable. The surgical system may be configured as a kit with
multiple sized and configured components.
[0017] It is envisioned that the present disclosure may be employed
to treat or repair bones damaged through injuries, disorders,
abnormalities and/or surgery. In one particularly useful
embodiment, spinal disorders or repairs such as, for example,
osteoporosis, curvature abnormalities, tumors, fractures, etc. may
be repaired. It is contemplated that the present disclosure may be
employed with other osteal and bone related applications, including
those associated with diagnostics and therapeutics. It is further
contemplated that the disclosed surgical system and methods may be
alternatively employed in a surgical treatment with a patient in a
prone or supine position, and/or employ various surgical approaches
to the spine, including anterior, posterior, posterior mid-line,
direct lateral, postero-lateral, and/or antero-lateral approaches,
and in other body regions. The present disclosure may also be
alternatively employed with procedures for treating the lumbar,
cervical, thoracic and pelvic regions of a spinal column. The
system and methods of the present disclosure may also be used on
animals, bone models and other non-living substrates, such as, for
example, in training, testing and demonstration.
[0018] The present disclosure may be understood more readily by
reference to the following detailed description of the disclosure
taken in connection with the accompanying drawing figures, which
form a part of this disclosure. It is to be understood that this
disclosure is not limited to the specific devices, methods,
conditions or parameters described and/or shown herein, and that
the terminology used herein is for the purpose of describing
particular embodiments by way of example only and is not intended
to be limiting of the claimed disclosure. Also, as used in the
specification and including the appended claims, the singular forms
"a," "an," and "the" include the plural, and reference to a
particular numerical value includes at least that particular value,
unless the context clearly dictates otherwise. Ranges may be
expressed herein as from "about" or "approximately" one particular
value and/or to "about" or "approximately" another particular
value. When such a range is expressed, another embodiment includes
from the one particular value and/or to the other particular value.
Similarly, when values are expressed as approximations, by use of
the antecedent "about," it will be understood that the particular
value forms another embodiment. It is also understood that all
spatial references, such as, for example, horizontal, vertical,
top, upper, lower, bottom, left and right, are for illustrative
purposes only and can be varied within the scope of the disclosure.
For example, the references "upper" and "lower" are relative and
used only in the context to the other, and are not necessarily
"superior" and "inferior".
[0019] Further, as used in the specification and including the
appended claims, "treating" or "treatment" of a disease or
condition refers to performing a procedure that may include
administering one or more drugs to a patient (human, normal or
otherwise or other mammal), in an effort to alleviate signs or
symptoms of the disease or condition. Alleviation can occur prior
to signs or symptoms of the disease or condition appearing, as well
as after their appearance. Thus, treating or treatment includes
preventing or prevention of disease or undesirable condition (e.g.,
preventing the disease from occurring in a patient, who may be
predisposed to the disease but has not yet been diagnosed as having
it). In addition, treating or treatment does not require complete
alleviation of signs or symptoms, does not require a cure, and
specifically includes procedures that have only a marginal effect
on the patient. Treatment can include inhibiting the disease, e.g.,
arresting its development, or relieving the disease, e.g., causing
regression of the disease. For example, treatment can include
reducing acute or chronic inflammation; alleviating pain and
mitigating and inducing re-growth of new ligament, bone and other
tissues; as an adjunct in surgery; and/or any repair procedure.
Also, as used in the specification and including the appended
claims, the term "tissue" includes soft tissue, ligaments, tendons,
cartilage and/or bone unless specifically referred to
otherwise.
[0020] The following discussion includes a description of a
surgical system and related methods of employing the surgical
system in accordance with the principles of the present disclosure.
Alternate embodiments are also disclosed. Reference will now be
made in detail to the exemplary embodiments of the present
disclosure, which are illustrated in the accompanying figures.
Turning now to FIGS. 1-4, there is illustrated components of a
surgical system, such as, for example, a cement delivery system 10
in accordance with the principles of the present disclosure.
[0021] The components of delivery system 10 can be fabricated from
biologically acceptable materials suitable for medical
applications, including metals, synthetic polymers, ceramics and
bone material and/or their composites, depending on the particular
application and/or preference of a medical practitioner. For
example, the components of delivery system 10, individually or
collectively, can be fabricated from materials such as stainless
steel alloys, commercially pure titanium, titanium alloys, Grade 5
titanium, superelastic titanium alloys, cobalt-chrome alloys,
stainless steel alloys, superelastic metallic alloys (e.g.,
Nitinol, super elasto-plastic metals, such as GUM METAL.RTM.
manufactured by Toyota Material Incorporated of Japan), ceramics
and composites thereof such as calcium phosphate (e.g., SKELITE.TM.
manufactured by Biologix Inc.), thermoplastics such as
polyaryletherketone (PAEK) including polyetheretherketone (PEEK),
polyetherketoneketone (PEKK) and polyetherketone (PEK), carbon-PEEK
composites, PEEK-BaSO.sub.4 polymeric rubbers, polyethylene
terephthalate (PET), fabric, silicone, polyurethane,
silicone-polyurethane copolymers, polymeric rubbers, polyolefin
rubbers, hydrogels, semi-rigid and rigid materials, elastomers,
rubbers, thermoplastic elastomers, thermoset elastomers,
elastomeric composites, rigid polymers including polyphenylene,
polyamide, polyimide, polyetherimide, polyethylene, epoxy, bone
material including autograft, allograft, xenograft or transgenic
cortical and/or corticocancellous bone, and tissue growth or
differentiation factors, partially resorbable materials, such as,
for example, composites of metals and calcium-based ceramics,
composites of PEEK and calcium based ceramics, composites of PEEK
with resorbable polymers, totally resorbable materials, such as,
for example, calcium based ceramics such as calcium phosphate,
tri-calcium phosphate (TCP), hydroxyapatite (HA)-TCP, calcium
sulfate, or other resorbable polymers such as polyaetide,
polyglycolide, polytyrosine carbonate, polycaroplaetohe and their
combinations. Various components of delivery system 10 may have
material composites, including the above materials, to achieve
various desired characteristics such as strength, rigidity,
elasticity, compliance, biomechanical performance, durability and
radiolucency or imaging preference. The components of delivery
system 10, individually or collectively, may also be fabricated
from a heterogeneous material such as a combination of two or more
of the above-described materials. The components of delivery system
10 may be monolithically formed, integrally connected or include
fastening elements and/or instruments, as described herein.
[0022] Delivery system 10 is employed, for example, with an open,
mini-open or minimally invasive surgical technique to apply bone
cement or other fluidized material to a bone, such as, for example,
a vertebra of a spine. Delivery system 10 includes a housing or
body 20, which provides support and contains components of the
delivery system 10. A spring 16 is provided in an upper portion of
the body 20 and is fixed to an end portion 21. Other biasing
mechanisms are also contemplated and may include spring-like
materials or structures. The spring 16 biases a reservoir piston 14
to provide pressure on a fluidized material 13 (e.g., cement)
disposed in a main reservoir 12.
[0023] A piston rod 22 passes through the body 20 and the end
portion 21. Portions of components of the delivery system 10 are
depicted in phantom so that internal components may be seen. For
example, the piston rod 22 is shown passing through the entire
dispensing system 10. Piston rod 22 includes a ball-shaped end
portion or ball end 26, which is disposed within a sleeve 24. The
ball end 26 is shown as having a spherical shape. It is
contemplated that other shapes may also be employed for the ball
end 26. The sleeve 24 includes an upper opening that has a
clearance fit with the piston rod 22 and an interference fit with
the ball end 26. A lower opening of the sleeve 24 has an
interference fit with ball-shaped end portion 26. This relationship
between the sleeve 24 and the piston ball 26 permits the piston
ball 26 to function as a valve and a piston for delivering cement
as will be explained in greater detail herein.
[0024] When the piston rod 22 is driven in the downward direction
to deliver cement 13, the ball end 26 seals against the sleeve 24
(at the lower portion), and cement 13 is driven from a delivery
chamber 28 through a fitting 30 or other dispensing structure
(e.g., a back flow device (not shown)). The fitting 30 may include
a Luer fitting, for example. The Luer fitting is a standardized
system of small-scale fluid fittings used for making leak-free
connections between a male-taper fitting and its mating female part
on medical and laboratory instruments, including hypodermic syringe
tips and needles or stopcocks and needles. The Luer fitting 30 may
receive a needle, syringe, nozzle, etc. (not shown) to dispense the
cement 13. During a stroke of the piston rod 22, cement 13 from the
main reservoir 12, which is pressurized by the spring 16 that is
attached to the main reservoir piston 14, flows in to fill a volume
displaced by a piston assembly 32 formed by the ball end 26 sealing
against the sleeve 24. During retraction of the piston assembly 32,
cement 13 is displaced from the main reservoir 12 into the delivery
chamber 28. This is due to the pressurized cement 13 in the main
reservoir 12 passing around the ball end 26 and through the
interior of the sleeve 24.
[0025] Bone cement is typically mixed prior to delivery to the
surgical site and delivered in a fluid state. That is, powdered
bone cement material is often mixed with a fluid such as water to
produce a pasty cement material that hardens upon curing. The
viscosity of the bone cement is dependent on the amount of water
present in the cement mixture and increases as time elapses after
mixing due to curing of the cement. Eventually, the cement hardens
to a solid material. The less water in the cement, the more viscous
the material and the higher the build up of pressures in the
delivery device. Controlling the pressure build up in the delivery
device is essential in preventing rupturing of the delivery device,
limiting potential injury to the surgeon and for preventing leakage
of the cement into the surgical site. Controlling the pressure
build up in the delivery device is also important for the precise
and proper delivery of the cement to the desired area.
[0026] Accordingly, delivery system 10 permits high viscosity
cement 13, e.g., poly(methyl methacrylate) (PMMA) or other types of
cement, to be delivered into a bone, e.g., a vertebral body, by
actuation of the piston rod 22. The piston rod 22 may be activated
manually or automatically. In one embodiment, the piston rod 22 is
activated from outside a fluoroscopy field if fluoroscopy is
employed for imaging during a procedure. The activation of the
piston rod 22 is preferably performed without using multiple
devices or accessories.
[0027] By employing the spring 16 to bias the reservoir piston 14,
high-pressure regions are eliminated resulting in increased safety
to the physician. In other systems, hydraulic and pneumatic systems
may develop high pressures in the reservoir, which could
potentially cause cement to explode out of the dispensing device
under certain conditions. The present embodiments act as an
alternative to using hydraulics to drive a floating or
reciprocating piston. This increases physician safety and
simplifies the product.
[0028] In accordance with the present principles, the delivery
system 10 is able to deliver cement by mechanically driving the
reciprocating piston assembly 32 via remote actuation (e.g., a
push-pull cable, etc.). The piston assembly 32 acts as a piston, a
valve and a positive displacement fill mechanism. The piston
assembly 32 will be shown and described in greater detail in FIGS.
2-4.
[0029] Referring to FIG. 2, a magnified view of a distal end
portion of the delivery system 10 of FIG. 1 is shown. The piston
rod 22 with the ball end 26 and the sleeve 24 function in two
modes. A first mode is for filling the delivery chamber 28. The
piston rod 22 is retracted in the direction of arrow "A". As the
ball end 26 is retracted, an opening 40 in the sleeve 24 is no
longer sealed off from the delivery chamber 28. Pressurized cement
13, being biased by the spring 16, is sent from the reservoir 12
passed the ball end 26 and the sleeve 28 through the opening 40 to
the delivery chamber 28. The delivery chamber 28 fills with the
cement 13 to await dispensing during a procedure.
[0030] In a second mode, cement 13 is dispensed from the delivery
chamber 28 when the piston rod 22 is moved in the direction of
arrow "B". The ball end 26 of the piston rod 22 engages the opening
40. The ball end 26 engages surfaces of the opening 40 to form a
seal to prevent cement from moving into or out of the opening 40.
As movement in the direction of arrow "B" continues, the ball end
26 of the piston rod 22 remains engaged with the opening 40 and
begins to impart motion to the sleeve 24 as well. The ball end 26
and the sleeve 24 work together to form a piston to eject cement 13
from the delivery chamber 28. The piston assembly 32 moves in
unison to force the cement 13 from the delivery chamber 28 to
dispense the cement 13 through the fitting 30. When cement 13 is
dispensed, the pressure on the delivery side closes a valve formed
by the ball end 26 in the opening 40 of the sleeve 24, restricting
the high-pressure region of the system 10 to the delivery chamber
28. When the piston is again retracted in the direction of arrow
"A", the ball end 26 and sleeve 24 decouple for a short time,
opening the valve to the main reservoir 12. As the piston rod 22
continues to retract, cement is again displaced from the main
reservoir 12 into the delivery chamber 28. This positive
displacement minimizes lag-time between actuations and allows for
partial strokes.
[0031] The delivery system 10 permits partial strokes and therefore
less than a full volume of the dispensing chamber 28 may be
dispensed. For example, when the piston rod 22 is advanced less
than a full stroke, the delivery chamber 28 delivers fluid
occupying less than its full volume. A dispensing pressure for the
fluid is achieved only in the delivery chamber 28, and does not
affect the main reservoir 12. Therefore, the high pressure
associated with dispensing cement is limited to a small area of the
dispensing system 10, namely the dispensing chamber 28.
[0032] Referring to FIGS. 3 and 4, an illustrative piston assembly
32 is shown in its two modes of operation. FIG. 3 shows the piston
rod 22 being retracted. The ball end 26 engages the sleeve 24 by
contacting engagement portions 42. The ball end 26 includes a
dimension larger than the piston rod 22. The portions 42 are
supported by supports 46. Since the supports 46 and portions 42 do
not completely occupy space around the ball end 26, when the ball
end 26 is in the position shown in FIG. 3, cement can bypass the
ball end 26 and enter the opening 40 into the delivery chamber (28)
below. The engagement portions 42 occupy only a fraction of a
surface area of the ball end 26 of the piston rod 22. This provides
area for the flow of fluid (cement) passed the ball end 26 when the
piston rod 22 is retracted.
[0033] FIG. 4 shows the piston rod 22 advanced so that the ball end
26 engages the opening 40 and forms a seal to prevent the passage
of cement through the opening 40. Here, the sleeve and the ball end
26 form a piston to enable a volume of the delivery chamber (28) to
be decreased with the advancing of the sleeve 24 and ball end
26.
[0034] While FIGS. 1-4 illustratively show a mechanism that
provides for the formation of a valve and a piston in accordance
with a direction that the mechanism is moved. It is contemplated
that additional or other structures may be employed to provide the
desired functionality in accordance with the present principles. It
is envisioned that the ball end 26 and its corresponding mating
surface on the opening 40 may have various configurations or
shapes, such as, for example, oval, oblong, triangular,
rectangular, square, polygonal, irregular, uniform, non-uniform,
variable and/or tapered. The ball end 26 may include a hemisphere,
a tear shape, a U-shape, etc.
[0035] It is further contemplated that the sleeve 24 may include
other features instead of or in addition to the supports 46 and
portions 42, such as for example, brackets, u-shaped frames,
multiple column supports, structural pegs and the like. These
features may have various dimensions, according to the requirements
of a particular application.
[0036] In assembly, operation and use, delivery system 10, similar
to the system described above, is employed with a surgical
procedure, such as, for treatment or repair of bones. For example,
as shown in FIGS. 1-4, delivery system 10, described herein, can be
employed with a surgical treatment of an applicable condition or
injury of an affected portion of a spinal column and adjacent areas
within a body, such as, for example, vertebrae.
[0037] In use, to treat vertebrae, a medical practitioner obtains
access to a surgical site including vertebrae in any appropriate
manner, such as through incision and retraction of tissues. It is
envisioned that delivery system 10 can be used in any existing
surgical method or technique including open surgery, mini-open
surgery, minimally invasive surgery and percutaneous surgical
implantation, whereby vertebrae is accessed through a
mini-incision, or sleeve that provides a protected passageway to
the area. Once access to the surgical site is obtained, the
particular surgical procedure can be performed for treating the
disorder. An incision is made in the body of a patient and a
cutting instrument (not shown) creates a surgical pathway for
implantation of components of delivery system 10. A preparation
instrument (not shown) can be employed to prepare tissue surfaces,
as well as for aspiration and irrigation of a surgical region
according to the requirements of a particular surgical application.
Prosthetics and necessary hardware, screws, posts, pins, etc. may
be installed.
[0038] The delivery system 10 accesses the surgical site along the
surgical pathway(s). The delivery system 10 is employed to inject
or deliver cement or other materials into or onto a bone or bones.
In one embodiment, delivery system 10 provides an agent, which may
be injected into the surgical site. The agent can be designed to
leach out of the cement once it is cured either in a burst or over
time so as to facilitate bone growth or treat the condition being
addressed. For example, it is envisioned that the agent included in
the cement may include bone growth promoting material. It is
contemplated that the agent may include therapeutic polynucleotides
or polypeptides. It is further contemplated that the agent may
include biocompatible materials, such as, for example,
biocompatible metals and/or rigid polymers, such as, titanium
elements, metal powders of titanium or titanium compositions,
sterile bone materials, such as allograft or xenograft materials,
synthetic bone materials such as coral and calcium compositions,
such as HA, calcium phosphate and calcium sulfite, biologically
active agents, for example, gradual release compositions such as by
blending in a bioresorbable polymer that releases the biologically
active agent or agents in an appropriate time dependent fashion as
the polymer degrades within the patient. Suitable biologically
active agents include, for example, BMP, Growth and Differentiation
Factors proteins (GDF) and cytokines. The components of delivery
system 10 can be made of radiolucent materials such as polymers.
Radiomarkers may be included for identification under x-ray,
fluoroscopy, CT or other imaging techniques. It is envisioned that
the agent may include one or a plurality of therapeutic agents
and/or pharmacological agents for release, including sustained
release, to treat, for example, pain, inflammation and
degeneration.
[0039] It is envisioned that the use of microsurgical and image
guided technologies may be employed to access, view and repair
spinal deterioration or damage, view and repair fractures or damage
to bones in the extremities of a patient, with the aid of delivery
system 10. Upon completion of the procedure, the surgical
instruments and assemblies are removed and the incision is
closed.
[0040] It will be understood that various modifications may be made
to the embodiments disclosed herein. Therefore, the above
description should not be construed as limiting, but merely as
exemplification of the various embodiments. Those skilled in the
art will envision other modifications within the scope and spirit
of the claims appended hereto.
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