U.S. patent application number 13/335581 was filed with the patent office on 2012-04-19 for method of fabricating a stiff anvil for a surgical instrument.
This patent application is currently assigned to CARDICA, INC.. Invention is credited to Bernard A. Hausen, Bryan D. Knodel, Philipe R. Manoux.
Application Number | 20120091183 13/335581 |
Document ID | / |
Family ID | 45374519 |
Filed Date | 2012-04-19 |
United States Patent
Application |
20120091183 |
Kind Code |
A1 |
Manoux; Philipe R. ; et
al. |
April 19, 2012 |
Method of Fabricating a Stiff Anvil for a Surgical Instrument
Abstract
A method of manufacturing a surgical apparatus may include
fabricating an anvil that includes an insert composed of a first
material, the insert located within a cavity in a body composed of
a second material, where the first material and the second material
have different properties.
Inventors: |
Manoux; Philipe R.; (San
Francisco, CA) ; Knodel; Bryan D.; (Flagstaff,
AZ) ; Hausen; Bernard A.; (Redwood City, CA) |
Assignee: |
CARDICA, INC.
Redwood City
CA
|
Family ID: |
45374519 |
Appl. No.: |
13/335581 |
Filed: |
December 22, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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12489355 |
Jun 22, 2009 |
8087562 |
|
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13335581 |
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Current U.S.
Class: |
227/175.1 ;
29/428; 29/527.5; 29/592 |
Current CPC
Class: |
A61B 2017/00526
20130101; Y10T 29/49 20150115; A61B 2017/07257 20130101; Y10T
29/49826 20150115; Y10T 29/49988 20150115; A61B 2017/00964
20130101; A61B 17/07207 20130101 |
Class at
Publication: |
227/175.1 ;
29/592; 29/428; 29/527.5 |
International
Class: |
A61B 17/04 20060101
A61B017/04; B23P 11/00 20060101 B23P011/00; B23P 17/00 20060101
B23P017/00; B23P 15/00 20060101 B23P015/00 |
Claims
1. A method of manufacturing a surgical apparatus, comprising:
fabricating an anvil comprising an insert composed of a first
material, said insert located within a cavity in a body composed of
a second material, wherein said first material and said second
material have different properties.
2. The method of claim 1, wherein said first material is
high-modulus and said second material is high-strength.
3. The method of claim 1, wherein said fabricating comprises
fabricating said insert; and then metal injection molding said body
about at least part of said insert.
4. The method of claim 1, wherein said fabricating comprises
fabricating said body; and then metal injection molding said into
said cavity in said body.
5. The method of claim 1, wherein said fabricating comprises
fabricating said insert; and then insert molding said body about at
least part of said insert.
6. The method of claim 1, wherein said fabricating comprises
fabricating said insert; separately fabricating said body;
inserting said insert into said cavity; and fixing said insert to
said body.
7. The method of claim 1, wherein said first material is tungsten
carbide and wherein said second material is 17-4 PH stainless
steel.
8. A surgical apparatus, comprising: an anvil, comprising van upper
layer composed of a first material; and a lower layer composed of a
second material different from said first material, said lower
layer fixed to said upper layer.
9. The surgical apparatus of claim 8, wherein said first material
is high-modulus and said second material is high-strength.
10. The surgical apparatus of claim 8, wherein said first material
is high-strength and said second material is high-modulus.
11. The surgical apparatus of claim 8, wherein each said layer
extends along substantially all of the entire length and width of
said anvil.
Description
[0001] This application is a divisional of U.S. patent application
Ser. No. 12/489,355, filed on Jun. 22, 2009, which is hereby
incorporated by reference in its entirety.
FIELD OF THE INVENTION
[0002] The invention generally relates to surgical staplers and
stapling.
BACKGROUND
[0003] Referring to FIG. 1, a surgical stapler 2 typically includes
a staple holder 4 and an anvil 6. The staple holder 4 and anvil 6
are configured to close together and clamp tissue therebetween.
After clamping, the staple holder 4 deploys a plurality of staples
into that tissue. A challenge faced by most surgical staplers 2 is
beam deflection. When the surgical stapler 2 clamps tissue that is
sufficiently thick and/or tough, the distal end of the anvil 6 may
not close completely relative to the staple holder 4. Instead, the
distal end of the anvil 6 may bend away from the staple holder 4,
because more force is required to compress the tissue than to cause
the distal end of the anvil 6 to bend. Many attempts have been made
to solve this problem. Some surgical staplers 2 utilize an "I-beam"
mechanism, where the upper and lower portions of the I-beam each
slide in a corresponding channel in the staple holder 4 and anvil
6. However, the I-beam takes up space in the surgical stapler 2,
limits cutting and stapling operations to being performed by motion
in the distal direction, and adds to the part count. Other surgical
staplers 2 have been proposed that utilize exotic, highly-stiff
materials to reduce or eliminate beam deflection. Stiffness is the
force required to produce a unit deflection of a structure, and is
related to the elastic modulus of the material from which the
structure is fabricated. Strength is the ability of a structure to
resist loads. However, it is a truism of material science that
stiff, high-modulus materials are not high-strength materials, with
the result that such materials are not practical for fabrication of
an anvil 6.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 is a side view of a surgical stapler.
[0005] FIG. 2 is a cross-section side view of an exemplary
anvil.
[0006] FIG. 3 is a cross-section end view of the anvil of FIG.
2.
[0007] FIG. 4 is a cross-section end view of another exemplary
anvil.
[0008] FIG. 5 is a cross-section end view of another exemplary
anvil.
[0009] The use of the same reference symbols in different figures
indicates similar or identical items.
DETAILED DESCRIPTION
[0010] U.S. Patent Application Publication No. 2009/0065552,
published on Mar. 12, 2009 (the "Endocutter Document"), is hereby
incorporated by reference herein in its entirety. The Endocutter
Document describes a surgical stapler 2 having a staple holder 4
and an anvil 6. The anvil 6 described in this document may be used
in place of the anvil 6 described in the Endocutter Document, or in
place of a convention anvil in any suitable surgical stapler 2.
[0011] Referring to FIGS. 2-3, an insert 8 is held within the body
10 of the anvil 6. That is, the body 10 is the part of the anvil 6
that receives the insert 8. The insert 8 may have any
cross-sectional shape, such as circular, oval, rectangular, square,
or any other suitable shape. The cross-sectional shape of the
insert 8 may be constant, or may vary, along the length of that
insert 8. The insert 8 may extend along part, or all, of the body
10 of the anvil 6. If the insert 8 extends along only part of the
body 10 of the anvil 6, the insert 8 may be located at any suitable
longitudinal position within the body 10 of the anvil 6.
Advantageously, the insert 8 is stiffer than the body 10, and the
body 10 is stronger than the insert 8. The insert 8 may be any
high-modulus material, such as, for example, tungsten carbide.
However, the insert 8 may be a different ceramic, metal, or any
other suitable high-modulus material. The body 10 may be any
high-strength material, such as, for example, 17-4 PH stainless
steel. However, the body 10 may be ceramic, a different metal, or
any other suitable high-strength material. Numerical analysis
indicates that the use of a tungsten carbide insert 8 in
conjunction with a 17-4 PH stainless steel body 10 results in an
anvil 6 approximately three times stiffer than an anvil 6 composed
of 17-4 PH stainless steel alone. The combination of a high-modulus
insert 8 and a high-strength body 10 results in an anvil 6 that is
stronger than the insert 8 alone could be, and stiffer than the
body 10 alone could be. Alternately, the insert 8 may be a
high-strength material, and the body 10 may be a high-modulus
material. For the purposes of this document, "high-modulus" of the
insert 8 or body 10 refers to a material having a higher modulus
than the material from which the other is fabricated. Similarly,
"high-strength" of the insert 8 or body 10 refers to a material
having a higher strength than the material from which the other is
fabricated.
[0012] The insert 8 and body 10 may be fabricated in any suitable
manner. As one example, the insert 8 and the body 10 may be
fabricated separately, and then the insert 8 may be placed into a
corresponding cavity 12 within the body 10. The insert 8 may be
held in place by a pressure or interference fit, by adhesive, by
welding, by pinning, or by any other method, mechanism and/or
structure. As another example, the body 10 may be insert-molded
about the insert 8, or vice versa. Metal injection molding may be
used to fabricate the body 10 about the insert 8, or to fabricate
the insert 8 within the cavity 12 defined in the body 10. As
another example, the body 10 may be cast about the insert 8. As
another example, the insert 8 may be cast in place within the
cavity 12.
[0013] Referring also to FIG. 4, a different exemplary anvil 6 may
include two or more inserts 8a, 8b held within the cavity in the
body 10. The inserts 8a, 8b may have any suitable cross-sectional
shape. For example, each insert 8a, 8b may have a generally
rectangular cross-sectional shape, where the rectangle is wider
than it is tall. The inserts 8a, 8b may have substantially the same
cross-sectional area and shape as one another, or may be shaped
and/or sized differently from one another. For example, one of the
inserts 8a, 8b may be thicker than the other. The inserts 8a, 8b
each may extend substantially the same length longitudinally,
and/or may be located in substantially the same longitudinal
position in the anvil 6. Alternately, at least one insert 8a, 8b
may be shorter than another, and/or may be located in a different
longitudinal position in the anvil 6. One insert 8a may be
fabricated from a high-strength material, and another insert 8b may
be fabricated from a high-modulus material; such inserts 8a, 8b may
be stacked relative to each other in any suitable order. If so, the
body 10 may be fabricated from plastic or other material, where the
anvil 6 relies on the inserts 8a, 8b for both strength or
stiffness, or may be fabricated from any other material, where the
anvil 6 does not rely entirely on the inserts 8a, 8b to provide
both strength and stiffness. Alternately, each insert 8a, 8b may be
fabricated from a high-strength material and the body 10 may be
fabricated from a high-modulus material, or vice versa.
[0014] Optionally, an upper insert 8a may be fabricated from a
material that is stronger in compression than in tension, and a
lower insert 8b may be fabricated from a material that is stronger
in tension than compression. The upper insert 8a is further from
the staple holder 4 than the lower insert 8b. The use of terms such
as "upper", "lower" and "upwards" merely refers to the orientation
of figures on the page for clarity and brevity, and does not limit
the arrangement of the staple holder 4 and anvil 6, nor the
orientation of the anvil 6 in use. In this way, as the anvil 6 and
staple holder 4, the tendency of the distal end of the anvil 6 to
bend upward away from the staple holder 4 is resisted both by the
tensile strength of the lower insert 8b and the ability of the
upper insert 8a to withstand compression. Typically, high modulus
materials are stronger in compression than in tension, so in such a
configuration the upper insert 8a may be fabricated from a
high-modulus material and the lower insert 8b may be fabricated
from a high-strength material.
[0015] Referring to FIG. 5, a different exemplary anvil 6 may be
fabricated from two separate, stacked layers 14a, 14b. In such a
configuration, an insert 8 may not be utilized. However, an insert
8 may be provided in conjunction with the two layers 14a, 14b if
desired; in such a configuration, the layers 14a, 14b may form the
body 10 of the anvil 6, and the insert 8 is received into the
cavity 12 of the body 10. The layers 14a, 14b may be fabricated
from different materials and stacked in any order. As one example,
an upper layer 14a may be fabricated from a high modulus material
such as tungsten carbide, and a lower layer 14b may be fabricated
from a high-strength material such as 17-4 PH stainless steel. As
another example, the upper layer 14a may be fabricated from a
high-strength material and the lower layer 14b may be fabricated
from a high modulus material. The layers 14a, 14b may be fixed to
one another to form a rigid anvil 6, and such fixation may be
accomplished in any suitable manner, such as by adhesive, by
welding, by pinning, by insert molding, or by metal injection
molding. Optionally, one layer 14 may include one or more apertures
(not shown) defined therein, and the other layer 14 may include one
or more projections (not shown) configured to be received in those
apertures. Such a configuration may facilitate the connection of
the layers 14 to one another. The layers 14a, 14b each may extend
along the entire length and width of the anvil 6. Alternately, at
least one layer 14 may extend along less than the entire length
and/or width of the anvil 6. If so, the other layer 14 may extend
upward or downward to fill the remaining space. Alternately, one
layer 14 may be composed of two or more separate pieces, each
extending along less than all of the entire length and/or width of
the anvil 6. In this way, the material properties of a particular
layer 14 may be fine-tuned. The layers 14a, 14b may each be
substantially the same height. Alternately, one layer 14 may be
thicker than the other, depending on the desired stiffness and/or
strength of the anvil 6 as a whole. As another example, the anvil 6
may be fabricated from three or more layers 14.
[0016] While the invention has been described in detail, it will be
apparent to one skilled in the art that various changes and
modifications can be made and equivalents employed, without
departing from the present invention. It is to be understood that
the invention is not limited to the details of construction, the
arrangements of components, and/or the method set forth in the
above description or illustrated in the drawings. Statements in the
abstract of this document, and any summary statements in this
document, are merely exemplary; they are not, and cannot be
interpreted as, limiting the scope of the claims. Further, the
figures are merely exemplary and not limiting. Topical headings and
subheadings are for the convenience of the reader only. They should
not and cannot be construed to have any substantive significance,
meaning or interpretation, and should not and cannot be deemed to
indicate that all of the information relating to any particular
topic is to be found under or limited to any particular heading or
subheading. Therefore, the invention is not to be restricted or
limited except in accordance with the following claims and their
legal equivalents.
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