U.S. patent application number 11/030019 was filed with the patent office on 2005-10-20 for method and instrumentation for performing minimally invasive hip arthroplasty.
Invention is credited to Hershberger, Troy W..
Application Number | 20050234462 11/030019 |
Document ID | / |
Family ID | 35097252 |
Filed Date | 2005-10-20 |
United States Patent
Application |
20050234462 |
Kind Code |
A1 |
Hershberger, Troy W. |
October 20, 2005 |
Method and instrumentation for performing minimally invasive hip
arthroplasty
Abstract
A broaching instrument and method using a segmented broach head.
First and second broach segments are laterally engageable with each
other in vivo, and are aligned with each other on a common
longitudinal axis when so engaged. The method involves making a
small anterior incision adjacent a patient's femur, inserting the
broach segments sequentially through the anterior incision,
interconnecting the plurality of broach segments in vivo,
connecting the broach handle to the broach segments, and broaching
the proximal medullary canal with the assembled multi-part broach
instrument.
Inventors: |
Hershberger, Troy W.;
(Winona Lake, IN) |
Correspondence
Address: |
William F. Bahret
BAHRET & ASSOCIATES
Suite 512
320 North Meridan Street
Indianapolis
IN
46204
US
|
Family ID: |
35097252 |
Appl. No.: |
11/030019 |
Filed: |
January 5, 2005 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11030019 |
Jan 5, 2005 |
|
|
|
10912644 |
Aug 5, 2004 |
|
|
|
60534270 |
Jan 5, 2004 |
|
|
|
Current U.S.
Class: |
606/85 |
Current CPC
Class: |
A61F 2002/30332
20130101; A61F 2002/30405 20130101; A61F 2220/0033 20130101; A61F
2220/0025 20130101; A61F 2002/30507 20130101; A61F 2002/4627
20130101; A61F 2/4603 20130101; A61F 2002/4638 20130101; A61B
17/1668 20130101; A61F 2/3676 20130101; A61B 17/1659 20130101; A61F
2002/3674 20130101; A61F 2002/4629 20130101; A61F 2002/4681
20130101; A61F 2/4637 20130101; A61F 2002/30337 20130101; A61F
2/3662 20130101; A61F 2/367 20130101; A61F 2/36 20130101; A61F
2002/30797 20130101; A61F 2/4607 20130101; A61F 2002/3625 20130101;
A61F 2/30744 20130101 |
Class at
Publication: |
606/085 |
International
Class: |
A61B 017/24 |
Claims
What is claimed is:
1. A broach instrument for preparing the proximal medullary canal
of a femur for receiving a hip stem implant, comprising: a first
broach segment defining a longitudinal axis; and a second broach
segment laterally engageable with said first broach segment in
vivo, said second broach segment being aligned with said first
broach segment on said longitudinal axis when engaged
therewith.
2. The instrument of claim 1, further comprising auxiliary means
for applying an axial force to said broach segments.
3. The instrument of claim 2, wherein said broach segments each
have a longitudinal bore therein, and wherein said means for
applying an axial force includes a core shaft extending through
said longitudinal bores.
4. The instrument of claim 3, further comprising a broach handle
having a bore therein for said core shaft, said core shaft being
rotatably mounted in said broach handle.
5. The instrument of claim 4, wherein said core shaft is axially
restrained by said broach handle and has a threaded fastener
portion on its distal end, and wherein the distalmost one of said
broach segments includes a mating threaded fastener portion for
engaging said core shaft and cooperating therewith to create a
compression force on said broach segments when said core shaft is
rotated in one direction.
6. The instrument of claim 4, wherein said core shaft threadedly
engages said broach handle and has an unthreaded distal end for
engaging the distalmost one of said broach segments to create a
tension force on said broach segments when said core shaft is
rotated in one direction.
7. The instrument of claim 4, wherein said broach handle has an
offset portion with a bore extending therethrough for said core
shaft, and wherein said core shaft is a flexible shaft.
8. The instrument of claim 1, wherein said first and second broach
segments include laterally engageable mating dovetail
connectors.
9. A method of preparing the proximal medullary canal of a
patient's femur for receiving a hip stem implant, comprising:
providing a multi-part broach instrument including a broach handle
and a segmented broach head having a plurality of broach segments;
making an anterior incision adjacent a patient's femur; inserting
said broach segments sequentially through said anterior incision;
interconnecting said plurality of broach segments in vivo;
connecting said broach handle to said broach segments; and
broaching said proximal medullary canal with the assembled
multi-part broach instrument.
10. The method of claim 9, wherein a compression force is applied
to said interconnected broach segments with an auxiliary
mechanism.
11. The method of claim 10, wherein said auxiliary mechanism is a
core shaft extending through a bore in said broach handle and a
bore in each of said broach segments.
12. The instrument of claim 11, wherein said core shaft is axially
restrained by said broach handle and has a threaded fastener
portion on its distal end, and wherein the distalmost one of said
broach segments includes a mating threaded fastener portion for
engaging said core shaft and cooperating therewith to create a
compression force on said broach segments when said core shaft is
rotated in one direction.
13. The method of claim 9, wherein a tension force is applied to
said interconnected broach segments with an auxiliary
mechanism.
14. The method of claim 13, wherein said auxiliary mechanism is a
core shaft extending through a bore in said broach handle and a
bore in each of said broach segments.
15. The instrument of claim 14, wherein said core shaft threadedly
engages said broach handle and has an unthreaded distal end for
engaging the distalmost one of said broach segments to create a
tension force on said broach segments when said core shaft is
rotated in one direction.
16. The instrument of claim 9, wherein said broach segments are
laterally engageable segments.
17. The instrument of claim 16, wherein said broach segments
include mating dovetail connectors.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application No. 60/534,270, filed Jan. 5, 2004, and U.S.
patent application Ser. No. 10/912,644, filed Aug. 5, 2004, both of
which applications are hereby incorporated by reference along with
the following applications filed on Jan. 5, 2005: Attorney Docket
No. 13007-24B entitled Method And Instrumentation For Performing
Minimally Invasive Hip Arthroplasty and filed in the name of Troy
W. Hershberger and Kimberly S. Parcher, and Attorney Docket No.
13007-24C entitled Method And Instrumentation For Performing
Minimally Invasive Hip Arthroplasty and filed in the name of Troy
W. Hershberger.
BACKGROUND OF THE INVENTION
[0002] This invention relates to methods and instruments for
performing hip arthroplasty, and more particularly to broach
instruments and methods for preparing the proximal femur to receive
a femoral implant as part of an implantable hip prosthesis.
[0003] In one popular method of performing a total hip arthroplasty
through two incisions, the femur is prepared by passing
instrumentation through a small posterior lateral incision. This
posterior incision is similar to the incision made when performing
a conventional femoral intramedullary nailing procedure except that
the incision is located somewhat more superior. A second, anterior
incision is made to facilitate the introduction of instrumentation
for preparation of the acetabulum as well as to expose the femur
from the anterior side. The surgeon is able to view the femur and
resect the femoral head from this anterior side. Access along the
femoral axis for reamers and broaches is most readily accomplished,
however, through the posterior lateral incision. The surgeon
bluntly divides the fibers of the gluteus maximus through the
posterior incision to develop a small tunnel through which he may
pass the femoral broaches, reamers and, eventually, the femoral
implant. The femur is broached through the posterior lateral
incision while the femur is viewed through the anterior
incision.
[0004] There are disadvantages associated with the prior method and
instrumentation described above. These include the necessity of
making the posterior lateral incision large enough to accommodate
passage of the femoral broach and other instrumentation. Also,
damage may be caused to the muscle fibers as well as the skin
margins by excessive stretching of tissue and by repeatedly passing
the broach and other instrumentation into and out of the posterior
lateral incision.
SUMMARY OF THE INVENTION
[0005] According to one aspect of the present invention, a broach
instrument for preparing the proximal medullary canal of a femur
for receiving a hip stem implant comprises a segmented broach head
which includes a first broach segment defining a longitudinal axis,
and a second broach segment laterally engageable with the first
broach segment in vivo, the second broach segment being aligned
with the first broach segment on the longitudinal axis when engaged
therewith.
[0006] Another aspect of the present invention is a novel method of
preparing the proximal medullary canal of a patient's femur using a
multi-part broaching instrument which includes a broach handle and
a segmented broach head having a plurality of broach segments. The
method comprises making a small anterior incision adjacent a
patient's femur, inserting the broach segments sequentially through
the anterior incision, interconnecting the plurality of broach
segments in vivo, connecting the broach handle to the broach
segments, and broaching the proximal medullary canal with the
assembled multi-part broach instrument.
[0007] The objects and advantages of the present invention will be
more apparent upon reading the following detailed description in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a side view of an assembled instrument according
to one embodiment of the present invention.
[0009] FIG. 2 is an exploded side view of the instrument of FIG.
1
[0010] FIG. 3 illustrates placement and insertion of the parts of
the instrument of FIG. 1 within a patient.
[0011] FIG. 4 is an exploded side view of another embodiment of the
present invention.
[0012] FIG. 5 is a detail view, partially in cross section, of the
embodiment of FIG. 4.
[0013] FIG. 6 is a side view of a further embodiment of the
instrument of the present invention.
[0014] FIG. 7 is an exploded side view of the embodiment shown in
FIG. 6.
[0015] FIG. 8 illustrates insertion and assembly of the parts of
the instrument of FIG. 7 within a patient.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] For the purpose of promoting an understanding of the
principles of the invention, 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 invention is thereby
intended, such alterations and further modifications in the
illustrated device and such further applications of the principles
of the invention as illustrated therein being contemplated as would
normally occur to one skilled in the art to which the invention
relates.
[0017] It is desired to reduce the size of incisions necessary to
perform a total hip arthroplasty in order to minimize trauma to the
gluteus muscles and other underlying tissue adjacent the hip joint.
According to the present invention, one approach to reducing the
size of the incisions is to divide the broaching instrument used to
broach the proximal medullary canal of the patient's femur into
separate pieces, allowing the size of the incisions necessary to
accommodate passage of the broach pieces to be reduced. The
multi-piece broach instrument may include a laterally segmented
broach head that may be inserted through the incisions and
assembled within the patient, further reducing the size of the
incisions necessary to accommodate passage of the broach segments
into the patient.
[0018] In a first embodiment of the present invention, shown in
FIG. 1, a multi-part broaching instrument 10 generally comprises a
core shaft 12, a laterally divided or segmented broach head 14, and
a broach handle 16. Core shaft 12, shown in FIG. 2, has a rigid
shaft 18 terminating in a threaded distal end portion 20 and a
proximal grip or knob 22. Broach handle 16 has an impact surface
24, an axial bore 26 for receiving the core shaft 12, a recess 28
for receiving the grip 22 and an anti-rotation key 30 for
preventing the broach head 14 from rotating about the core shaft 12
during use.
[0019] The broach head 14 may be laterally divided or segmented
into a plurality of broach segments as shown in FIG. 2. A distal
broach segment 32 has a tip 34 sized and shaped to guide the
instrument 10 into the femoral canal, a threaded aperture 36 for
receiving the threaded end portion 20 of the core shaft 12, and a
receiver slot 38 about the threaded aperture 36, shown as a
dovetail type design. An intermediate broach segment 40 has an
axial bore 42 therethrough positioned to align with the axial bore
26 of the broach handle 16 when assembled, a second receiver slot
44 about the axial bore 42 and a connector portion 46, shown as a
dovetail type design, for insertion into the receiver slot 38 of
the distal broach segment 32. A proximal broach segment 48 has an
axial bore 50 therethrough positioned to align with the axial bores
42, 26 of the intermediate broach segment 40 and the broach handle
16 when assembled, and a second connector portion 52, also shown as
a dovetail type design, for insertion into the second receiver slot
of the intermediate broach segment. The broach segments and the
handle may have a rectangular or curved cross-section, and the
broach segments may be serrated partially or completely around the
circumference thereof.
[0020] The instrument 10 is assembled during a total hip
arthroplasty procedure as shown in FIG. 3. First, the broach
segments 32, 40 and 48 are preferably inserted one at a time
through the anterior incision 54 in the body of the patient 56.
Segment 32 may be inserted first and positioned in the proximal
medullary canal, then segment 40 may be inserted and laterally
connected to segment 32, and then segment 48 may be inserted and
laterally connected to segment 40. Alternatively, intermediate
segment 40 may be inserted after segments 32 and 48 and connected
therebetween. Next, the broach handle 16 is preferably inserted
through the posterior incision 58 in the body of the patient 56.
Next, the core shaft 12 is preferably advanced through the axial
bores 26, 42 and 50 of the broach handle 16 and broach segments 40,
48. Finally, the core shaft 12 is rotated so that the threaded end
portion 20 engages the threaded aperture 36 of the distal broach
segment 32 so that the broach segments 32, 40 and 48 are drawn
together against the broach handle 16. The core shaft restrains
lateral movement of the broach segments to a degree by simple
insertion therein, but its threaded tip is preferably screwed into
broach segment 32 sufficiently to create a compression force which
tightly secures the broach segments. Once assembled, the instrument
10 is manipulated through the posterior incision 58 of the patient
56 to broach the femoral canal 60 in preparation for receiving the
hip stem implant.
[0021] When the broaching procedure is completed, the instrument 10
is preferably removed and disassembled in reverse order. First, the
core shaft 12 is preferably rotated so that the threaded end
portion 20 disengages the threaded aperture 36 of the distal broach
segment 32 and is then removed from the broach segments 32, 40, 48
and broach handle 16. Next, the broach handle 16 is preferably
removed from the posterior incision 58 of the patient 56. Finally,
the broach segments 32, 40, 48 are then preferably removed from the
patient 56 through the anterior incision 54 one at a time.
[0022] In another embodiment of the present invention, shown in
FIGS. 4 and 5, a multi-part broaching instrument 110 employs a
push-type design in which a core shaft 112 pushes against the
distal broach segment 132 of a laterally segmented broach head 114,
cooperating with the broach handle 116 to put the broach segments
132, 140 and 148 in tension. In this embodiment, the core shaft 112
may have an unthreaded distal tip 120 and the distal broach segment
132 may have an unthreaded mating aperture 136. Alternatively, the
distal broach segment 132 may have no aperture other than the
receiver slot in its dovetail joint. The broach segments 132, 140,
148 and the broach handle 116 are restrained longitudinally by
their interconnected dovetail joints, and the core shaft 112, which
is threaded into the broach handle 116, is used to create a tension
force in the broach segments 132, 140, 148 by turning the knob 122
clockwise (for a right-handed thread as illustrated) to advance it
toward the adjacent surface of the broach handle 116. The advancing
distal tip 120 of the core shaft 112 engages the closed distal end
of aperture 136 in the distal broach segment 132 and thus applies a
distally directed force against that broach segment, thereby
putting all the broach segments and the handle in tension.
[0023] A push-type design may alternatively be implemented with
oppositely threaded portions on the two opposite ends of the core
shaft. For example, instead of having an unthreaded distal tip,
core shaft 112 may have left-hand threads on its distal end which
act in opposition to the right-hand threads on its proximal end in
the handle. That is, when rotated clockwise, the core shaft tends
to back out of the distalmost broach segment and thereby further
pushes on that segment as the threaded proximal end of the core
shaft moves distally in the broach handle. The same core shaft may
alternatively be used to put the broach segments in compression, by
rotating the core shaft sufficiently in the counter-clockwise
direction and thereby tending to draw the broach segments tightly
together. In another alternative embodiment, the core shaft may
have a hook-type end which engages the distalmost broach segment
and pulls it toward the other broach segments as the core shaft is
retracted in the broach handle. The broaching instrument is
otherwise assembled and used in the same way as broaching
instrument 10 previously described and illustrated.
[0024] In a further embodiment of the invention, shown in FIGS.
6-8, a multi-part broaching instrument 210 generally comprises a
flexible core shaft 212, an offset broach handle 216 and, a
laterally segmented broach head 214 as previously described and
shown. Flexible core shaft 212 may be made of nitinol (NiTi) or
wound cable terminating in a threaded end 220 and a tightening grip
or knob 222. Offset broach handle 216 has an internal bore 226 for
receiving core shaft 212, a recess 228 for receiving the tightening
grip 222 and an anti-rotation key 230 for preventing the broach
head 214 from rotating about core shaft 212 during use.
[0025] The instrument 210 is assembled during a total hip
arthroplasty procedure as shown in FIG. 8. First, the broach
segments 232, 240, 248 are preferably inserted one at a time
through an anterior incision 254 made in the body of the patient
256 as previously described. Next, the offset broach handle 216 is
then preferably inserted through the anterior incision 254 and
positioned adjacent the broach head segments 232, 240, 248. Next,
the flexible core shaft 212 is then preferably advanced through the
internal bore 226 of the offset broach handle 216 and the axial
bores 242, 250 of the broach head segments 240, 248. Finally, the
core shaft 212 is rotated so that the threaded end 220 of the core
shaft 212 is threadedly engaged with the threaded aperture 236 of
the distal broach segment 232, creating a compression force that
draws the broach segments 232, 240, 248 tightly against the offset
broach handle 216. Once assembled, the instrument 210 is
manipulated through the anterior incision 254 in the body of the
patient 256 to broach the femoral canal 260 in preparation for
receiving the hip stem implant.
[0026] When the broaching procedure is completed, the instrument
210 is preferably removed and disassembled in reverse order. First,
the flexible core shaft 212 is preferably rotated so that the
threaded end 220 disengages the threaded aperture 236 of the distal
broach segment 232 and is then removed from the broach segments
232, 240, 248 and offset broach handle 216. Next, the offset broach
handle 216 is preferably removed from the anterior incision 254 in
the body of the patient 256.
[0027] While the invention has been illustrated and described in
detail in the drawings and foregoing description, the same is to be
considered as illustrative and not restrictive in character, it
being understood that only the preferred embodiment has been shown
and described and that all changes and modifications that come
within the spirit of the invention are desired to be protected. For
example, while a core shaft is described above as a preferred means
for applying an axial force to the parts of the segmented broach
head, alternative means are contemplated, such as a peripheral
strap, a pair of peripheral straps, or other device extending
alongside the broach segments, e.g., in a longitudinal groove
therein, for creating a compression force. Rigid and semi-rigid
rods and other peripheral devices are also contemplated in certain
embodiments for creating tension in the broach segments.
* * * * *