U.S. patent application number 10/837039 was filed with the patent office on 2005-07-07 for method of implanting an acetabular shell.
This patent application is currently assigned to Paramount Medical Instruments, L.L.C.. Invention is credited to Parry, Douglas S., Parry, Scott R..
Application Number | 20050149043 10/837039 |
Document ID | / |
Family ID | 34714391 |
Filed Date | 2005-07-07 |
United States Patent
Application |
20050149043 |
Kind Code |
A1 |
Parry, Douglas S. ; et
al. |
July 7, 2005 |
Method of implanting an acetabular shell
Abstract
A method and apparatus for implanting acetabular components into
an acetabulum utilizing a minimally invasive incision. The method
and apparatus utilize a subatmospheric pressure formed in a hollow
passage of an elongate body to secure an acetabular shell to a
shell-engaging head removably attached to a coupler end of the
elongate body. Liner-engaging heads may also be removably attached
to the coupler end to install socket liners into an implanted
acetabular shell. The elongate body may comprise a bent portion to
allow access to the acetabulum through a minimally invasive
incision.
Inventors: |
Parry, Douglas S.; (Sandy,
UT) ; Parry, Scott R.; (Sandy, UT) |
Correspondence
Address: |
KARL R CANNON
PO BOX 1909
SANDY
UT
84091
US
|
Assignee: |
Paramount Medical Instruments,
L.L.C.
|
Family ID: |
34714391 |
Appl. No.: |
10/837039 |
Filed: |
April 30, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60534431 |
Jan 5, 2004 |
|
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|
60541344 |
Feb 2, 2004 |
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Current U.S.
Class: |
606/91 |
Current CPC
Class: |
A61F 2002/4685 20130101;
A61F 2/34 20130101; A61F 2/4609 20130101; A61F 2/4603 20130101;
A61F 2002/30616 20130101; A61B 17/00234 20130101; A61B 17/8872
20130101; A61F 2002/4681 20130101; A61B 17/92 20130101; A61F
2002/4635 20130101 |
Class at
Publication: |
606/091 |
International
Class: |
A61B 017/58 |
Claims
What is claimed is:
1. A method for implanting an acetabular shell into an acetabulum,
the method comprising the steps of: incising a hip to expose the
acetabulum; preparing the acetabulum to receive the acetabular
shell; providing an acetabular shell impactor having an elongate
body and a distal end on which an engaging head may be selectively
disposed, the elongate body comprising a hollow passage; disposing
the engaging head on the distal end of the impactor, the engaging
head being configured to receive the acetabular shell; placing the
acetabular shell onto the engaging head; closing off the hollow
passage, such that movement of the acetabular shell relative to the
distal end of the impactor causes a subatmospheric pressure to be
produced within the hollow passage to thereby temporarily secure
the acetabular shell onto the engaging head; and positioning the
acetabular shell into the acetabulum with the impactor.
2. The method of claim 1, further comprising the step of applying
an impaction force to the impactor to implant the acetabular
shell.
3. The method of claim 1, wherein the step of incising a hip
creates a minimally invasive incision.
4. The method of claim 1, wherein the step of disposing the
engaging head comprises the step of rotatably engaging the engaging
head with a coupler end.
5. The method of claim 1, wherein the step of disposing the
engaging head comprises the step of slidably engaging the engaging
head with a coupler end.
6. The method of claim 1, wherein the step of disposing the
engaging head comprises the step of engaging the engaging head with
the coupler end by a snap fit.
7. The method of claim 1, further comprising forming a
pressure-maintaining seal between the engaging head and the
acetabular shell.
8. The method of claim 1, wherein the step of incising a hip
creates an incision between about two and one-half inches and about
five inches.
9. The method of claim 1, wherein the step of incising a hip
creates an incision less than five and one-half inches.
10. A method for implanting an acetabular shell into an acetabulum,
the method comprising the steps of: incising a hip to expose the
acetabulum; preparing the acetabulum to receive the acetabular
shell; providing an acetabular shell impactor having an elongate
body comprising a hollow passage, the impactor further comprising a
port in fluid communication with the hollow passage; placing the
acetabular shell onto the impactor; sealing the port with a part of
the human body, such that movement of the acetabular shell relative
to the distal end of the impactor causes a subatmospheric pressure
to be produced within the hollow passage to thereby temporarily
secure the acetabular shell onto the impactor; and positioning the
acetabular shell into the acetabulum.
11. The method of claim 10, further comprising the step of applying
an impaction force to the impactor to thereby implant the
acetabular shell.
12. The method of claim 10, further comprising the step of
providing the impactor with a head disposed at a proximal end of
the elongate body, the head having a top surface being configured
to receive an impaction force, the port being positioned in the top
surface.
13. The method of claim 10, wherein the step of sealing the port
further comprises the step of sealing the port with a thumb from a
hand of a surgeon that is grasping the elongate body.
14. The method of claim 10, wherein the step of incising a hip
creates a minimally invasive incision.
15. The method of claim 10, wherein the step of incising a hip
creates an incision between about two and one-half inches and about
five inches.
16. The method of claim 10, wherein the step of incising a hip
creates an incision less than five and one-half inches.
17. The method of claim 10, further comprising the step of
providing the elongate body with a bent portion, the bent portion
configured to at least partially fit in a minimally invasive
incision.
18. The method of claim 17, further comprising the step of
providing the elongate body with a straight portion.
19. The method of claim 10, further comprising the step of
installing a removeable engaging head on said elongate body.
20. A method for implanting an acetabular shell into an acetabulum,
the method comprising the steps of: incising a hip with a minimally
invasive incision to provide access to the acetabulum; providing an
acetabular shell impactor having an elongate body, a port, a head
and a coupler end, the elongate body extending from the coupler end
to the head and comprising a hollow passage, the elongate body
further comprising a bent portion adapted to fit at least partially
in the minimally invasive incision, the port in fluid communication
with the hollow passage; placing the acetabular shell onto the
impactor; and applying an impaction force to the impactor to
implant the acetabular shell.
21. The method of claim 20, installing an engaging head onto the
coupler end with a pressure-maintaining seal, the engaging head
configured to receive the acetabular shell.
22. The method of claim 20, further comprising sealing the port
with a part of the human body.
23. The method of claim 21, further comprising forming a partial
vacuum in the hollow passage to temporarily secure the acetabular
shell onto the engaging head.
24. The method of claim 20, further comprising positioning the
acetabular shell into the acetabulum with the impactor.
25. The method of claim 20, wherein the step of incising a hip
creates an incision between about two and one-half inches and about
five and one-half inches.
26. The method of claim 20, wherein the step of incising a hip
creates an incision less than about five and one-half inches.
27. The method of claim 20, further comprising the step of
providing the elongate body with a straight portion interposed
between the bent portion and the head.
28. The method of claim 23, wherein the step of forming a
subatmospheric pressure further comprises the step of moving the
acetabular shell with respect to the engaging head.
29. The method of claim 22, wherein the step of sealing the port
further comprises the step of sealing the port with a thumb from a
hand of a surgeon that is grasping the elongate body.
30. A method for implanting an acetabular shell and a socket liner
into an acetabulum, the method comprising the steps of: incising a
hip to provide access to the acetabulum; providing an impactor
having an elongate body and a coupler end for selectively engaging
an engaging head and a liner-engaging head, the engaging head being
configured to receive the acetabular shell and the liner-engaging
head being configured to receive the socket liner; installing the
engaging head onto the coupler end; securing the acetabular shell
onto the engaging head; positioning the acetabular shell into the
acetabulum with the impactor; removing the engaging head from the
coupler end and installing the liner-engaging head in its place;
and positioning the socket liner on the implanted acetabular shell
with the impactor.
31. The method of claim 30, further comprising applying an
impaction force to the impactor to implant the acetabular
shell.
32. The method of claim 30, further comprising coupling the socket
liner to the implanted shell by applying an impaction force.
33. The method of claim 30, wherein the step of incising a hip
creates a minimally invasive incision.
34. The method of claim 30, wherein the step of installing the
engaging head comprises the step of rotatably engaging the engaging
head with the coupler end.
35. The method of claim 30, wherein the step of installing the
engaging head comprises the step of slidably engaging the engaging
head with the coupler end.
36. The method of claim 30, further comprising the step of forming
a pressure-maintaining seal between the engaging head and the
acetabular shell.
37. The method of claim 30, wherein the step of incising a hip
creates an incision between about two and one-half inches and about
five and one-half inches.
38. The method of claim 30, wherein the step of incising a hip
creates an incision less than about five and one-half inches.
39. A method for installing an implant in a patient, the method
comprising the steps of: (a) joining said implant with an impactor;
(b) forming a pressure-maintaining region between said implant and
said impactor; (c) holding said implant on said impactor at least
in part by a sub-atmospheric pressure in said region created when
said impactor is moved in a direction away from said implant; and
(d) positioning said implant in said patient with said
impactor.
40. A method for implanting an acetabular shell into an acetabulum
of a patient, the method comprising the steps of: incising a hip to
provide access to the acetabulum; providing an acetabular shell
impactor having a body extending from a proximal end to a distal
end, the body having a bend connected to the distal end and a
straight portion connected to the proximal end, the bend comprising
a first segment, a second segment, and a third segment such that
the first segment extends from a longitudinal axis of the impactor
at an angle, the second segment extends substantially parallel to
the longitudinal axis of the impactor, and the third segment
extends back toward the longitudinal axis of the impactor, wherein
the second segment extends substantially parallel to the
longitudinal axis a distance that is at least 10 percent of a
distance between said proximal end and said distal end along said
longitudinal axis; disposing the acetabular shell on the distal end
of the impactor; positioning the acetabular shell into the
acetabulum with the impactor until at least a portion of the bend
is positioned into the patient; impacting the proximal end of the
impactor to drive the acetabular shell into the acetabulum;
disengaging the acetabular shell from the impactor while the
acetabular shell is embedded in the acetabulum; removing the
impactor from the patient; and closing the incision.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 60/534,431, filed Jan. 5, 2004, and U.S.
Provisional Application No. 60/541,344, filed Feb. 2, 2004, which
applications are hereby incorporated by reference herein in their
entireties, including but not limited to those portions that
specifically appear hereinafter, the incorporation by reference
being made with the following exception: In the event that any
portion of the above-referenced provisional applications is
inconsistent with this application, this application supercedes
said above-referenced provisional applications.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable.
BACKGROUND
[0003] 1. The Field of the Invention
[0004] The present disclosure relates generally to surgical
instruments, and more particularly, but not necessarily entirely,
to an apparatus and method for implanting surgical prostheses
during surgery.
[0005] 2. Description of Related Art
[0006] The number of total hip replacement surgeries has increased
dramatically in recent years. Hip replacement surgery involves
implanting a prosthesis to replace an ailing hip joint. The
prosthesis is typically made up of two parts: an acetabulum
component, or socket portion, which replaces the acetabulum and a
femoral component, which replaces the femoral head. The acetabulum
component may in turn comprise a metal shell, hereinafter referred
to as an acetabular shell, with a plastic or ceramic inner socket
liner, hereinafter referred to as a socket liner.
[0007] The steps for replacing the hip begin with the surgeon
making an incision over the hip joint. There are several different
approaches used to make the incision, usually based on the
surgeon's training and preferences. After the incision is made, the
ligaments and muscles may be separated to allow the surgeon access
to the bones of the hip joint. Once the hip joint is entered, the
femoral head may be dislocated from the acetabulum. Then the
femoral head may be removed by cutting through the femoral neck
with a saw. After the femoral head is removed, the cartilage may be
removed from the acetabulum using a power drill and a special
reamer. The reamer may be used to form the bone in a hemispherical
shape to exactly fit the acetabular shell of the acetabular
component. Once the right size and shape is determined for the
acetabulum, the acetabular shell may be inserted into place. In the
uncemented variety of artificial hip replacement, the acetabular
shell may be simply held in place by the tightness of the fit or
with screws to hold the metal shell in place. Insertion of the
acetabular shell may be done by hand or by use of a hand tool that
grips the shell. Often, the surgeon may set the acetabular shell
into the acetabulum by impacting it through the use of a mallet and
an impaction device. The surgeon may then insert a socket liner
into the acetabular shell. Once the acetabular shell and socket
liner are in place, the surgeon may then replace the femoral head
with a femoral component and the surgeon may reassemble the hip
joint. The surgeon may also test the movement of the hip joint
before closing the incision.
[0008] One of the major difficulties confronting the surgeon during
hip replacement surgery is the relatively inaccessible location of
the acetabulum making it difficult for the surgeon to correctly
position the acetabular components. In the past, the solution has
been to make a relatively large incision to allow the surgeon
complete and unfettered access to the hip joint. However, from the
patient's perspective, a large incision is undesirable as it
increases the trauma to the patient and the recovery time.
[0009] Attempts have been made in the previously available devices
to provide a hand tool to assist in holding and positioning an
acetabular shell. U.S. Pat. No. 5,116,339 (granted May 26, 1992 to
Glock) discloses an installation tool having an expanding head for
engaging the acetabular shell. The acetabular shell is released by
contracting the head when the shell is in position. The head is
expanded and contracted by means of a threaded shaft with a knob
such that rotation of the knob correspondingly expands or contracts
the head. U.S. Pat. No. 4,305,394 (granted on Dec. 15, 1981 to
Bertuch) discloses an acetabular shell positioning device
comprising an interchangeable ball and flange for engaging the
inner cavity of the acetabular shell by a mechanical engagement. A
coupling rod with a handle is manipulated in order to engage and
release the acetabular shell.
[0010] U.S. Pat. No. 3,859,992 (granted on Jan. 14, 1975 to
Amstutz) discloses a suction-operated holding and positioning
instrument for use in inserting an acetabular shell during hip
surgery. The Amstutz device includes a permanently affixed
shell-engaging head and an external suction source for forming a
suction force between the shell-engaging head and the shell. The
Amstutz device further provides a port controlled by a mechanical
valve for selectively breaking the suction force formed between the
shell-engaging head and the shell. The Amstutz device does not
appear to be able to be used with cementless acetabular shells that
require impaction.
[0011] The above devices are characterized by several disadvantages
including complicated designs involving several moving parts that
both increase manufacturing costs as well as making the device more
difficult to use during an operation. In particular, the Amstutz
device disadvantageously requires a connection to an external
suction source. The Amstutz device further does not allow for
interchangeable shell-engaging heads to allow the device to be used
with different sized acetabular shells. Finally, it appears that
none of the above devices can be used to both implant an acetabular
shell and a socket liner.
[0012] In addition, the shape of the devices dictate the use of
relatively large incisions during surgery. One attempted
improvement over the previously available devices to reduce the
size of the required incision is disclosed in U.S. Patent
Publication Application 2003/0229356 (published Dec. 11, 2003 to
Dye). The Dye apparatus includes a curved impaction instrument for
aligning and impacting the acetabular component into the
acetabulum. The curved shape of the apparatus allows for a
minimally invasive incision in the patient.
[0013] Similarly, U.S. Patent Publication Application 2003/0050645
(published Mar. 13, 2003 to Parker et al.) discloses a curved
impactor having a hollow outer shaft and a flexible drive shaft
disposed in the outer shaft. The flexible drive shaft is connected
at one end to a coupler, and at the opposite end is a thumb wheel,
such that rotation of the thumb wheel rotates the drive shaft and
engages the coupler to an acetabular shell.
[0014] Unfortunately, despite their advantages, both the Dye and
Parker et al. apparatuses still has several shortcomings. In
particular, the attachment of the acetabular shell to the device
requires a mechanical engagement of the shell to the device. Dye is
particularly disadvantageous due to the fact that it does not teach
a remote release of the acetabular shell once it is installed in
the acetabulum. Parker et al., on the other hand, is
disadvantageous due to its overly complicated remote release
mechanism.
[0015] The prior art is thus characterized by several disadvantages
that are addressed by the present disclosure. The present
disclosure minimizes, and in some aspects eliminates, the
above-mentioned failures, and other problems, by utilizing the
methods and structural features described herein. The features and
advantages of the disclosure will be set forth in the description
which follows, and in part will be apparent from the description,
or may be learned by the practice of the disclosure without undue
experimentation. The features and advantages of the disclosure may
be realized and obtained by means of the instruments and
combinations particularly pointed out in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The features and advantages of the disclosure will become
apparent from a consideration of the subsequent detailed
description presented in connection with the accompanying drawings
in which:
[0017] FIG. 1 is an exploded perspective view of one exemplary
embodiment made in accordance with the present disclosure.
[0018] FIG. 2 is a cross-sectional view of one exemplary embodiment
of an impactor.
[0019] FIG. 2A is a cross-sectional, break-away view of an
alternative embodiment of the impactor of FIG. 2.
[0020] FIG. 3 is an end view of the impactor illustrated in FIG. 2
made in accordance with the present disclosure.
[0021] FIG. 4A is a top view of an exemplary engaging head made in
accordance with the present disclosure.
[0022] FIG. 4B is a side view of an exemplary engaging head made in
accordance with the present disclosure.
[0023] FIG. 4C is a bottom view of an exemplary engaging head made
in accordance with the present disclosure.
[0024] FIG. 5 is a cross-sectional side view of the impactor,
shell-engaging head and an acetabular shell made in accordance with
the present disclosure.
[0025] FIG. 6 is a cross-sectional side view of another embodiment
of an engaging head made in accordance with the present
disclosure.
[0026] FIG. 7 is a cross-sectional side view of still another
embodiment of an engaging head made in accordance with the present
disclosure.
[0027] FIG. 8A is a side view of an exemplary embodiment of a
liner-engaging head made in accordance with the present disclosure
made in accordance with the present disclosure.
[0028] FIG. 8B is a top view of the liner-engaging head made in
accordance with the present disclosure.
[0029] FIG. 8C is a bottom view of the liner-engaging head made in
accordance with the present disclosure.
[0030] FIG. 9 is a cross-sectional side view of the liner-engaging
head mounted on the impactor made in accordance with the present
disclosure.
[0031] FIG. 10 is a perspective view of an exemplary embodiment of
an impactor having a positioning handle made in accordance with the
present disclosure.
DETAILED DESCRIPTION
[0032] For the purposes of promoting an understanding of the
principles in accordance with the disclosure, reference will now be
made to the embodiments illustrated in the drawings and specific
language will be used to describe the same. It will nevertheless be
understood that no limitation of the scope of the disclosure is
thereby intended. Any alterations and further modifications of the
inventive features illustrated herein, and any additional
applications of the principles of the disclosure as illustrated
herein, which would normally occur to one skilled in the relevant
art and having possession of this disclosure, are to be considered
within the scope of the disclosure claimed.
[0033] It is also to be understood that the terminology employed
herein is used for the purpose of describing particular embodiments
only and is not intended to be limiting since the scope of the
present disclosure will be limited only by the appended claims and
equivalents thereof.
[0034] It must be noted that, as used in this specification and the
appended claims, the singular forms "a," "an," and "the" include
plural referents unless the context clearly dictates otherwise. In
describing and claiming the present disclosure, the following
terminology will be used in accordance with the definitions set out
below. As used herein, the terms "comprising," "including,"
"containing," "characterized by," and grammatical equivalents
thereof are inclusive or open-ended terms that do not exclude
additional, unrecited elements or method steps.
[0035] Applicant has discovered a simple and easy to use apparatus
for positioning and implanting an acetabular shell into the a
patient's acetabulum during hip replacement surgery using minimally
invasive surgical techniques. Applicant's disclosure may also be
utilized to implant a socket liner in an implanted acetabular
shell. Importantly, Applicant's disclosure does not require a
mechanical engagement means to engage and hold the acetabular shell
during implantation. Instead, Applicant's disclosure teaches the
use of subatmospheric pressure to hold the acetabular shell on an
engaging head. One aspect of the disclosure is unique in that an
external suction source may not be required in order to create the
subatmospheric pressure. Applicant's disclosure may also comprise a
valveless and open port sealable by a finger for allowing the
subatmospheric pressure to be created and to be broken, to thereby
selectably release the acetabular shell from an engaging head. In
addition, another aspect of the Applicant's disclosure may permit
the use of interchangeable engaging heads thereby permitting the
implantation of acetabular shells and socket liners of different
sizes with the same apparatus.
[0036] As used herein, the term "minimally invasive incision" means
an incision as is known in the art to reduce trauma in the patient,
for example an incision ranging between about two and one-half
inches and about five and one-half inches. As used herein, the term
"pressure-maintaining seal" means a seal that inhibits airflow to a
degree sufficient to enable a non-atmospheric pressure to be
established and maintained at a non-atmospheric level, whether the
non-atmospheric pressure is constant or varies within a
non-atmospheric range.
[0037] Referring now to FIG. 1, reference numeral 8 generally
refers to an acetabular shell impactor assembly pursuant to one
embodiment of the Applicant's disclosure. The assembly 8 may
comprise an impactor 10 and a tool or engaging head, such as a
shell-engaging head 18, disposed on the impactor 10. The impactor
10 may comprise an elongate body 12 extending from a distal end 11
to a proximal end 13. A coupler end 14 and a head 16 may be
disposed on the distal end 11 and the proximal end 13,
respectively. The elongate body 12 may have a hollow passage 54 in
its interior extending between the coupler end 14 and the head 16
as can best be seen in FIG. 2, and said hollow passage 54 may be
closeable.
[0038] Referring back to FIG. 1, the elongate body 12 may further
comprise a first portion 20 extending from the proximal end 13
along a longitudinal axis 40 towards the coupler end 14. The first
portion 20 may be substantially straight and may be used as a
handle by a surgeon during surgery to assist in positioning the
impactor 10. In particular, a surgeon grasping the handle near the
proximal end 13 may be able to place the thumb of the hand grasping
the handle over the port 42 located on the top surface 17 of the
head 16, in order to seal the port 42 with a pressure-maintaining
seal and thereby close the hollow passage 54 when an implant such
as shell 62 is disposed on the engaging head 18.
[0039] A second portion 22 of the elongate body 12 may extend
between the first portion 20 and the coupler end 14. The second
portion 22 may form a bend in the elongate body 12 such that the
second portion 22 may, if desired, deviate from and return to the
longitudinal axis 40. The second portion 22 may comprise a first
segment 23A, a second segment 23B, and a third segment 23C as shown
in FIG. 1. The first segment 23A may be connected to the first
portion 20 at an angle such that the first segment 23A departs from
the longitudinal axis 40. The second segment 23B may be connected
to the first segment 23A. The second segment 23B may be
substantially parallel to the longitudinal axis 40. The third
segment 23C may be connected to the second segment 23B at an angle
such that the third segment 23C is directed back towards the
longitudinal axis 40 in the direction of the coupler end 14. In one
embodiment of the present disclosure, the second segment 23B may
extend substantially parallel to the longitudinal axis 40 a
distance d, that may be at least 10 percent of a distance d2
extending between the proximal end 13 and the distal end 11 of the
impactor 10 along the longitudinal axis 40, as shown in FIG. 1.
[0040] The bend in the second portion 22 may be sized and shaped
such that the coupler end 14 can be positioned inside of the
patient while the head 16 is positioned outside of the patient. It
will be appreciated by those skilled in the art that the bend in
the second portion 22 may allow an acetabular shell to be
positioned and impacted into a reamed acetabulum through a
minimally invasive incision. Further, the bend in the second
portion allows the impactor 10 to be positioned so as not to
interfere with other anatomical structures around the acetabulum
while the acetabular shell is brought into and implanted into the
acetabulum. Further, the bend may allow an almost linear transfer
of an impaction force from the head 16 to an acetabular shell along
the longitudinal axis 40 without disturbing the surrounding
anatomical structures.
[0041] In will be appreciated that the bend may be located on the
impactor 10 at different locations along the elongate body 12 to
facilitate varying surgical techniques. Further, the bend may be
curved, elliptical, piecewise linear, or circular in shape with a
constant or varying curvature. In this regard, it will be
appreciated that the second portion 22 may have alternative
embodiments other than then bend as described above. For example,
the second portion 22 may be curved, arced or circular. In some
embodiments, the second portion 22 may even be straight. It should
also be noted that the elongate body 12 may be of modular or one
piece construction. The modular construction may include a
combination of linear or non-linear segments. It will be understood
that the bend and the elongate body 12 may constitute a means for
positioning an acetabular shell into an acetabulum through a
minimally invasive incision.
[0042] As mentioned, the head 16 may be disposed on the proximal
end 13 of the elongate body 12. As can best be seen in FIG. 3, the
head 16 may comprise a top surface 17 that may be planar, and an
annular rim 24. The top surface 17 may be of sufficient size to
receive an impaction force from a surgical mallet or the like. The
annular rim 24 may protect the hand of the surgeon holding the
impactor 10 from missed or glancing blows from the surgical
mallet.
[0043] In addition, in the center of the top surface 17 may be a
port 42 as viewed in FIG. 3. The port 42 may be in fluid
communication with the hollow passage 54 in the elongate body 12 as
is best shown in FIG. 2. The port 42 may be sized and positioned in
the top surface 17 such that a thumb can placed over the port 42 to
thereby create a pressure-maintaining seal. The port 42 may be
situated along the longitudinal axis 40. It should be noted, that
it is within the scope of this disclosure that the position of the
port 42 may be located anywhere on the head 16 or the elongate body
12. For example, in reference to FIG. 2A, it will be appreciated
that a port 42a may be formed to extend through the elongate body
12 in a radial direction, in lieu of port 42 in FIG. 2.
[0044] The port 42 may be valveless and open. As used herein, the
term "open" means in fluid communication with the atmosphere such
that the atmosphere may enter the hollow passage 54 through the
port 42 when the port 42 is not sealed. Moreover, while it is less
desirable, a mechanical valve as is known in the art may be used to
operate and seal the port 42, but typically the port 42 may be
sealed with the thumb of a surgeon as described above. It will be
understood that the port 42 may constitute a means for selectively
breaking a subatmospheric pressure in the hollow passage 54.
[0045] The coupler end 14 of the impactor 10 as shown in FIG. 1 may
be utilized to removably and interchangeably attach the engaging
head capable of engaging a surgical implant, such as a
shell-engaging head 18 or a socket-liner-engaging head 58 (see
FIGS. 7 and 8). The coupler end 14 may comprise an annular flange
26 extending radially from the longitudinal axis 40. The side of
the annular flange 26 facing away from the distal end 11 may form a
seat 27 against which an engaging head may be oriented.
[0046] Extending from the middle of the seat 27 along the
longitudinal axis 40 and in a direction away from the distal end 11
may be an extension member 28. The extension member 28 may extend
in a substantially perpendicularly direction from the seat 27 and
may be substantially cylindrical in shape but it will be
appreciated by those skilled in the art that other shapes may be
permissible that are consistent with the present disclosure.
[0047] The extension member 28 may comprise an outer surface having
a forward-most annular groove and a rear-most annular groove each
of which are adapted to receive a resilient member 30, such as an
o-ring. An exposed end 31 of the extension member 28 may have a
port 32 located thereon in fluid communication with hollow passage
54 in the elongate body 12 as may be observed best in FIG. 2. The
port 32 may be centered on or off of the longitudinal axis 40.
[0048] As will be discussed in more detail below, the extension
member 28 may be sized and shaped to slidably and removably engage
an engaging head, such as a shell-engaging head 18 or a
socket-liner-engaging head 58 (see FIGS. 7 and 8), by a
pressure-maintaining seal. It should be noted, however, that other
methods of attaching an engaging head to the coupler end 14 are
known to those skilled in the art that fall within the scope of
this disclosure. For example, an engaging head may rotatably engage
the coupler end 14. Also, an engaging head may be permanently
mounted onto the coupler end 14. Alternatively, the engaging head
and the impactor 10 may be constructed as a one-piece unitary
member. Moreover, with respect to the resilient members 30, a
pressure-maintaining seal may be formed by using either a single
resilient member 30, or a pair of resilient members 30 as shown
most clearly in FIG. 2, or some other plurality of resilient
members 30, may be positioned in a variety of locations either on
the engaging head or the coupler end 14 as is known in the art to
facilitate the formation of a pressure-maintaining seal between the
coupler end 14 and the engaging head. Further, it will be
appreciated that the resilient members 30 may not be required at
all for achieving the pressure-maintaining seal. It will be
understood that the coupler end 14 may constitute a means for
selectively engaging any one of a plurality of engaging heads by a
pressure-maintaining seal.
[0049] A cross-sectional view of the impactor 10 is shown in FIG.
2. As previously mentioned, the hollow passage 54 extends from the
distal end 11 to the proximal end 13 of the elongate body 12
through both the first portion 20 and the second portion 22. Port
42 may be positioned in the top surface 17 of the head 16 and may
be interconnected with the hollow passage 54 by a fluid
communication path 43. Likewise, port 32 may be positioned in the
exposed end 31 and may be interconnected with the hollow passage 54
by a fluid communication path 33. In addition, port 42 and port 32
may constitute the only egresses from the hollow passage 54. It
will be observed, that both port 42 and port 32, as well as fluid
communication paths 33 and 43 may lie on the longitudinal axis
40.
[0050] The size of the ports 42 and 32 may be smaller than that of
the hollow passage 54. As explained above, port 42 may be
configured and sized such that it may be sealed by a thumb of a
surgeon. As will be explained in greater detail below, port 32 may
be configured and sized to align with a fluid communication path in
an engaging head. Typically, fluid communication path 43 is through
the head 16 while fluid communication path 33 is through the
coupler end 14. It will be appreciated, however, that it is a
feature of this disclosure that the ports 42 and 32 may be
positioned anywhere along the impactor 10. It will be understood
that the hollow passage 54 may constitute a means for forming a
subatmospheric pressure.
[0051] Annular flange 26 may extend radially from the longitudinal
axis 40 while extended member 28 may extend parallel and along the
axis 40 away from the distal end 11. Seat 27 and exposed end 31 may
be perpendicular to the longitudinal axis 40. Resilient members 30
on the extended member 28 may be radially positioned from the axis
40.
[0052] FIGS. 1, 4A, 4B, and 4C show an isometric view, a top view,
side view and a bottom view, respectively, of one embodiment of the
shell-engaging head 18 which, as mentioned above, may be removably
attachable to the coupler end 14 of the impactor 10. The
shell-engaging head 18 may comprise a base portion 48 and a tip
portion 34 extending from a surface 50 of the base portion 48. The
tip portion 34 may be substantially partially spherical, such as a
substantially hemispherical. The tip portion 34 may extend such
that is substantially centered on the surface 50 of the base
portion 48.
[0053] The tip portion 34 may further comprise an annular groove 35
on its outer surface 37 that may be adapted to receive a resilient
member 36 (not shown in FIG. 4A, 4B or 4C), such as an o-ring. A
port 38 may be positioned in the outer surface 37. Located in a
rearmost portion 52 of the base portion 48 may be a recessed
portion 46 having a port 39 in fluid communication with port 38 on
the outer surface 37.
[0054] Looking now to a cross-sectional view of the engagement of
the engaging member 18 and the coupler end 14, the recessed portion
46 may slidably engage the extended member 28 as shown in FIG. 5.
The rearmost of the resilient members 30 on the extension member 28
may engage an annular locking grove 44 formed in a side wall 47 of
the recessed portion 46 in order to form a friction fit to hold the
engaging member 18 on the coupler end 14. The frontmost resilient
member 30 on the extension member 28 may also engage the side wall
47 of the recessed portion 46 which may provide an additional seal
as well as a friction fit to hold the engaging head onto the
coupler end 14. It will be appreciated that the engagement between
the rearmost of the resilient members 30 and the locking groove 44
may also form a pressure-maintaining seal.
[0055] The rearmost portion 52 of the base portion 48 may abut
directly against the seat 27 of the annular flange 26 when the
shell-engaging head 18 is installed on the coupler end 14. This
interaction may serve to properly orient the shell-engaging head
18. Likewise, the exposed end 31 of the extension member 28 may
abut against a bottom portion 56 of the recessed portion 48.
[0056] It will be observed that when the shell-engaging head 18 is
properly installed onto the coupler end 14, that port 32 is in
alignment and adjacent with port 39 such that port 38 is in direct
fluid communication with the hollow passage 54. In this regard, the
fluid communication path 33 may be interconnected with a fluid
communication path 60 extending from port 38 to port 39.
[0057] In the above described arrangement, the shell-engaging-head
18 may be removed from the impactor 10 by using sufficient force to
pull it off. It will be appreciated that the force to pull off the
shell-engaging head 18 should be such that it can be done by an
average strength human being as it may be necessary during surgery
to replace the shell-engaging head 18.
[0058] It will also be noted that an engaging head may be disposed
on the elongate body in a modular or integral manner. It will be
appreciated that if the engaging head is disposed on the elongate
body in an integral manner, that a coupler end 14 is not needed and
the engaging head may be disposed directly on the distal end 11.
Alternatively, modular embodiments of the engaging head may have an
intervening structure, such as the coupler end 14, between the
engaging head and the distal end 11. It is to understood that the
phrase "disposed on," when used in reference to the engaging head
being disposed on an object (such as the distal end of the elongate
body 12), means that the engaging head is held in relation to said
object either in a modular or integral manner, either directly or
indirectly. Referring now specially to FIG. 5, the forgoing
definition of the engaging head being "disposed on" an object,
includes the concept that the engaging head 18 is disposed on the
distal end 11 of the elongate member 12, because said engaging head
18 is held in relation to said distal end 11, even though engaging
head 18 and distal end 11 are not in any contact, but are
intercoupled by the coupler end 14.
[0059] FIG. 5 also illustrates the engagement of an acetabular
shell 62 having an outer surface 64 and an inner surface 66 with
the shell-engaging head 18. A rearmost portion 68 of the shell 62
may abut against the surface 50 of the shell-engaging head 18 when
the tip portion 34 is inserted into shell 62. Resilient member 36
disposed in groove 35 on the outer surface 37 may form a
pressure-maintaining seal with the inner surface 66 of the shell
62. An enclosed region 70 may be defined by the inner surface 66
and the outer surface 37. The enclosed region 70 may be in fluid
communication with the hollow passage 54 and may be substantially
airtight.
[0060] FIGS. 6 and 7 illustrate alternative embodiments of engaging
heads indicated by reference numerals 100 and 120, respectively. In
FIG. 6, the engaging head 100 may comprise a base portion 102
having a surface 106 and a rearmost portion 104. A tip portion 110
may extend from the surface 106. The tip portion 110 may comprise
at least one frustoconical portion 113 having two resilient members
111 disposed in annular grooves 116 for forming a substantially
airtight enclosed region with an inner portion of an acetabular
shell. It will be appreciated that the enclosed region may be
between the two resilient members 111. Ports 114 may be positioned
between the two resilient members 111 and be fluidly connected by a
fluid communication path 118 to a port 112 located within a
recessed portion 108. As before, the recessed portion 108 may have
a locking groove 109 to engage the extension member 28 of the
coupler end 14 as was described above and is incorporated here by
reference.
[0061] FIG. 7, illustrates an engaging head 120 that may be similar
to that in FIG. 6, except that there may be only a single resilient
member 126 in an annular groove 127 formed in the tip portion 121.
Ports 128 may be fluidly connected to port 130 in the recessed
portion 122 by a fluid communication path 132.
[0062] In will be appreciated that embodiments of engaging heads
may include various configurations all of which fall within the
scope of the present disclosure. Some of these various
configurations may include, without limitation, some of the
following features in any combination: a tip portion having one,
two or three resilient members in its outer surface, one, two or
three ports in the recessed portion in fluid communication, either
individually or in combination, with one, two or three ports in the
outer surface, one, two or three ports located in the outer surface
disposed at any location on the tip portion, and a tip portion
having a partially spherical shape, substantially hemispherical
shape, a shape having one or more frustoconical portions, or any
random shape fitting with a inner portion of an acetabular shell or
implant.
[0063] It will be appreciated that the various embodiments of the
engaging head enable the Applicant's disclosure to be utilized with
the numerous variations in the structure of acetabular shells on
the market today or may be on the market in the future. For
example, some acetabular shells may comprise screw holes for
anchoring the shell into the acetabulum. An appropriate embodiment
of the engaging head consistent with Applicant's disclosure may be
able to engage that shell as described herein.
[0064] Once the shell-engaging head 18 has been installed on the
impactor 10 by an engagement with the coupler end 14, it may then
be used to position and impact the acetabular shell 62 into the
acetabulum of a patient at the appropriate time. The acetabular
shell 62 may be held onto the shell-engaging head 18 by a
subatmospheric pressure formed in the hollow passage 54. In one
embodiment, the subatmospheric pressure may be formed by placing
the acetabular shell over the tip portion 34 of the shell-engaging
head 18. The resilient member 36 on the outer surface 37 may
airtightly seal an enclosed region defined by the outer surface 37
and an inner surface of the acetabular shell. It will be
appreciated that at this point, the hollow passage 54 may have only
one other egress, the port 42. The surgeon then may place his or
her thumb over the port 42 located on the head 16.
[0065] When the port 42 is initially sealed by the surgeon, the
hollow passage 54 is substantially airtight and it will be observed
that the air pressure inside of the hollow passage 54 may be
equalized with the atmospheric pressure for a brief period of time.
Due to the configuration of the shell-engaging head 18, a
subatmospheric pressure may be formed when the acetabular shell
attempts to move away from the shell-engaging head 18, or vice
versa. This may be due to that fact that no outside air can enter
the hollow passage 54 while the volume of the airtight region is
being increased. It will be understood that as used herein,
reference to movement of a portion of the impactor assembly 8 with
respect to the shell or implant includes situations in which the
implant remains stationary and the impactor assembly 8 moves, or
situations in which the implant moves and the impactor assembly 8
remains stationary, or situations in which both the implant and the
impactor assembly 8 move with respect to each other.
[0066] It will be appreciated that the movement of the shell away
from the shell-engaging head 18 may be unobservable to the human
eye. Once the subatmospheric pressure has been formed, the surgeon
can then properly position the acetabular shell in the acetabulum
using principles and techniques that are well known in the art and
will not be recited here. Once the acetabular shell is in the
correct position, the thumb may be removed from the port 42 and the
pressure inside of the hollow passage 54 may again equalized with
atmospheric pressure thereby releasing the acetabular shell. A
surgical mallet may then be used to implant the shell into the
acetabulum by striking the head 16 of the impactor 10.
[0067] It will be observed that the prior art is devoid of
acetabular shell impactors utilizing a subatmospheric pressure to
hold an implant without moving parts. Moreover, the prior art only
teaches the use of an external suction source having a permanently
fixed engaging head. In particular, it is observed that the Amstutz
patent does not teach or suggest that a subatmospheric pressure may
be formed by the interaction of the engaging head and the implant,
i.e., the movement of the engaging head away from the implant.
[0068] A side view, top view, a rear view of a liner-engaging head
150 are shown in FIGS. 8A, 8B, and 8C respectively. The
liner-engaging head 150 may be used to install a socket liner 157
(see FIG. 9) into an implanted acetabular shell using the impactor
10 by engaging the socket portion of the socket liner 157. It will
be appreciated that the socket liner 157 may be formed in various
different sizes and configurations known in the art, and the
liner-engaging head 150 may be configured to be compatible with the
socket liner 157. The liner-engaging head 150 may comprise a tip
portion 151 that may be partially spherical in shape. As mentioned,
the tip portion 151 may be configured and sized to fit within the
socket of the socket liner 157. The tip portion 151 may be
resilient in nature to form a friction fit with the socket liner
157.
[0069] A base portion 152 of the liner-engaging head 150 may have a
rearmost portion 155. Relief grooves 158 may extend from the
forward most portion 153 towards the rearmost portion 155. In one
embodiment, four relief grooves 158 may be used. However, it will
be understood that any number of relief grooves 158 may be used
within the scope of the present disclosure. A port 160 may be
positioned in the forward most portion 153. A recessed portion 156
configured to engage the extension member 28 of the coupler end 14
may extend from the rearmost portion 155 towards the forward most
portion 153. A port 162 may be located in the recessed portion
156.
[0070] Looking now to a cross-sectional view of the engagement of
the insert-engaging head 150 and the coupler end 14, the recessed
portion 156 may slidably engage the extended member 28 as shown in
FIG. 9. The forward most of the resilient members 30 on the
extension member 28 may engage an annular locking grove 164 formed
in a side wall 166 of the recessed portion 156 in order to form a
friction fit to hold the insert-engaging member on the coupler end
14. The rearmost resilient member 30 on the extension member 28 may
also engage the side wall 166 of the recessed portion 156 which a
friction fit to hold the insert-engaging head 150 onto the coupler
end 14.
[0071] The rearmost portion 155 of the base portion 152 may abut
directly against the seat 27 of the annular flange 26 when the
insert-engaging head 150 is installed on the coupler end 14. This
interaction may serve to properly orient the insert-engaging head
150. Likewise, the exposed end 31 of the extension member 28 may
abut against a bottom portion 166 of the recessed portion 156.
[0072] It will be observed that when the insert-engaging head 150
is properly installed onto the coupler end 14, that port 32 is in
alignment and adjacent with port 162 such that port 160 is in
direct fluid communication with the hollow passage 54. In this
regard, the fluid communication path 33 may be interconnected with
a fluid communication path 168 extending from port 160 to port
162.
[0073] Like the shell-engaging head 18, in the above described
arrangement, the insert-engaging head 150 may be removed from the
impactor 10 by using sufficient force to pull it off. It will be
appreciated that the force to pull off the insert-engaging head 150
should be such that it can be done by an average strength human
being as it may be necessary during surgery to replace the
insert-engaging head 150.
[0074] After an acetabular shell has been implanted as described
above, the surgeon may then remove the shell-engaging head 18 from
the impactor 10 and install an appropriately sized liner-engaging
head 150. The surgeon can then attach the socket liner 157 to the
liner-engaging head 150 by inserting the tip portion 151 into the
socket. The tip portion 151 may engage the socket by a friction
fit. The socket liner 157 can then be positioned and implanted into
the previously implanted acetabular shell. This may require an
impaction force delivered to the head 16 by a surgical mallet. It
will be appreciated that the head 16 may constitute a means for
receiving an impaction force.
[0075] Once the socket liner 157 has been implanted into the shell,
the socket liner 157 may then be disengaged from the liner-engaging
head 150 so that the impactor 10 may be removed. The relief grooves
158 prevent and port 160 reduce the hydraulic suction that is
sometimes generated between the liner-engaging head 150 and the
socket liner when synorial fluid or another fluid is present. It
will be appreciated that other embodiments of insert-engaging heads
may be possible that fall within the scope of the present
disclosure. Moreover, it will also be understood that another
embodiment of the impactor 10 may be formed without the hollow
passage 54 for use with the liner-engaging head 150.
[0076] It will also be appreciated that the base portions of the
different engaging heads described above in their various
embodiments, i.e. engaging heads and liner-engaging heads and their
respective varying embodiments, may have a common configuration
such that they may engage the same impactor. The common
configuration allows engaging heads of different sizes and types to
be used interchangeably on the same impactor. For example,
different patients and circumstances may require different sized
acetabular shells that may not be determined until during surgery.
The common configuration of the engaging heads facilitates the
process by providing a single impactor with a plurality of engaging
heads and liner-engaging heads.
[0077] FIG. 10 illustrates another embodiment of an impactor 170.
An optional arm 172 may be coupled to an elongated body 174. The
arm 172 may comprise an extended portion 176 and a handle 178. The
arm 172 may be removably coupled by means of a threaded portion
(not shown) on the end of the extended portion 176 that may
rotatably engage a threaded bore 180 on the elongated body 174. The
arm 172 may assist the surgeon in positioning the impactor 174
during surgery as is known in the art.
[0078] In accordance with the features and combinations described
above, a useful method of implanting an acetabular shell may
include the steps of:
[0079] (a) incising a hip with a minimally invasive incision to
expose the acetabulum;
[0080] (b) preparing the acetabulum;
[0081] (c) providing an impactor having an elongate body, a head
and a coupler end, the elongate body further comprising a bent
portion and a hollow passage;
[0082] (d) installing an engaging head onto the coupler end;
[0083] (e) securing an acetabular shell to the engaging head by a
subatmospheric pressure;
[0084] (f) positioning the shell into the acetabulum; and
[0085] (g) applying an impaction force to the head in order to
implant the shell into the acetabulum.
[0086] It will be understood that the structure disclosed herein
may form one embodiment of a means for removably attaching an
engaging head to an elongate body in a pressure-maintaining manner,
such that any one of a plurality of engaging heads can be attached
to the elongate body for installing surgical implants of different
sizes. It should be appreciated that any structure, apparatus or
system for removably attaching an engaging head which performs
functions the same as, or equivalent to, those disclosed herein are
intended to fall within the scope of a means for removably
attaching an engaging head in a pressure-maintaining manner,
including those structures, apparatus or systems for removably
attaching an engaging head which are presently known, or which may
become available in the future. Anything which functions the same
as, or equivalently to, a means for removably attaching an engaging
head in a pressure-maintaining manner falls within the scope of
this element.
[0087] It will be appreciated that the elongate body 12 having a
bent portion as disclosed herein is merely one example of a means
for positioning an acetabular shell through a minimally invasive
incision, and it should be appreciated that any structure,
apparatus or system for positioning an acetabular shell through a
minimally invasive incision which performs functions the same as,
or equivalent to, those disclosed herein are intended to fall
within the scope of a means for positioning an acetabular shell
through a minimally invasive incision, including those structures,
apparatus or systems for positioning an acetabular shell through a
minimally invasive incision which are presently known, or which may
become available in the future. Anything which functions the same
as, or equivalently to, a means for positioning an acetabular shell
through a minimally invasive incision falls within the scope of
this element.
[0088] It will be appreciated that the head 16 disclosed herein is
merely one example of a means for receiving an impaction force, and
it should be appreciated that any structure, apparatus or system
for receiving an impaction force which performs functions the same
as, or equivalent to, those disclosed herein are intended to fall
within the scope of a means for receiving an impaction force,
including those structures, apparatus or systems for receiving an
impaction force which are presently known, or which may become
available in the future. Anything which functions the same as, or
equivalently to, a means for receiving an impaction force falls
within the scope of this element.
[0089] It will be appreciated that the coupler end 14 as disclosed
herein is merely one example of a means for selectively engaging an
engaging head by a pressure-maintaining seal, and it should be
appreciated that any structure, apparatus or system for selectively
engaging an engaging head by a pressure-maintaining seal which
performs functions the same as, or equivalent to, those disclosed
herein are intended to fall within the scope of a means for
selectively engaging an engaging head by a pressure-maintaining
seal, including those structures, apparatus or systems for
selectively engaging an engaging head by a pressure-maintaining
seal which are presently known, or which may become available in
the future. Anything which functions the same as, or equivalently
to, a means for selectively engaging an engaging head by a
pressure-maintaining seal falls within the scope of this
element.
[0090] It will be appreciated that the hollow passage 54 disclosed
herein is merely one example of a means for forming a
subatmospheric pressure, and it should be appreciated that any
structure, apparatus or system for forming a subatmospheric
pressure which performs functions the same as, or equivalent to,
those disclosed herein are intended to fall within the scope of a
means for forming a subatmospheric pressure, including those
structures, apparatus or systems for forming a subatmospheric
pressure which are presently known, or which may become available
in the future. Anything which functions the same as, or
equivalently to, a means for forming a subatmospheric pressure
falls within the scope of this element.
[0091] It will be appreciated that the port 42 herein is merely one
example of a means for breaking a subatmospheric pressure, and it
should be appreciated that any structure, apparatus or system for
breaking a subatmospheric pressure which performs functions the
same as, or equivalent to, those disclosed herein are intended to
fall within the scope of a means for breaking a subatmospheric
pressure, including those structures, apparatus or systems for
breaking a subatmospheric pressure which are presently known, or
which may become available in the future. Anything which functions
the same as, or equivalently to, a means for breaking a
subatmospheric pressure falls within the scope of this element.
[0092] Those having ordinary skill in the relevant art will
appreciate the advantages provide by the features of the present
disclosure. For example, it is a feature of the present disclosure
to provide an acetabular shell impactor with no moving parts.
Another feature of the present disclosure to provide an acetabular
shell impactor that utilizes a production of subatmospheric
pressure to hold the acetabular shell on an engaging head of the
impactor, without the need for an external subatmospheric pressure
producing source. It is a further feature of the present
disclosure, in accordance with one aspect thereof, to provide an
acetabular shell impactor having interchangeable engaging heads to
facilitate a hip replacement surgery. It is still another feature
of the present disclosure to provide an acetabular shell impactor
having interchangeable engaging heads and interchangeable
liner-engaging heads.
[0093] In the foregoing Detailed Description, various features of
the present disclosure are grouped together in a single embodiment
for the purpose of streamlining the disclosure. This method of
disclosure is not to be interpreted as reflecting an intention that
the claimed disclosure requires more features than are expressly
recited in each claim. Rather, as the following claims reflect,
inventive aspects lie in less than all features of a single
foregoing disclosed embodiment. Thus, the following claims are
hereby incorporated into this Detailed Description by this
reference, with each claim standing on its own as a separate
embodiment of the present disclosure.
[0094] It is to be understood that the above-described arrangements
are only illustrative of the application of the principles of the
present disclosure. Numerous modifications and alternative
arrangements may be devised by those skilled in the art without
departing from the spirit and scope of the present disclosure and
the appended claims are intended to cover such modifications and
arrangements. Thus, while the present disclosure has been shown in
the drawings and described above with particularity and detail, it
will be apparent to those of ordinary skill in the art that
numerous modifications, including, but not limited to, variations
in size, materials, shape, form, function and manner of operation,
assembly and use may be made without departing from the principles
and concepts set forth herein.
* * * * *