U.S. patent application number 11/931823 was filed with the patent office on 2008-06-12 for method and apparatus for securing tissue.
Invention is credited to Peter M. Bonutti.
Application Number | 20080140116 11/931823 |
Document ID | / |
Family ID | 30119315 |
Filed Date | 2008-06-12 |
United States Patent
Application |
20080140116 |
Kind Code |
A1 |
Bonutti; Peter M. |
June 12, 2008 |
METHOD AND APPARATUS FOR SECURING TISSUE
Abstract
An anchor has a pointed end portion may be utilized to form an
opening in a bone in a patient's body. The anchor is moved into the
opening formed in the bone in the patient's body with a suture
connected to the anchor. The suture may then be utilized to retain
body tissue in a desired position relative to the bone. The body
tissue may be either hard or soft body tissue. If desired, the
anchor may be utilized in conjunction with layers of soft body
tissue. When a suture is used it may be secured by connecting a
retainer with the suture. Alternatively, sections of the suture may
be interconnected. It is believed that it may be preferred to
secure the suture in place after at least a predetermined tension
has been established in the suture and/or a predetermined force has
been transmitted to the body tissue. The suture may be secured in
place by exposing a retainer to ultrasonic vibratory energy or by
applying the ultrasonic vibratory energy directly to sections of
the suture.
Inventors: |
Bonutti; Peter M.;
(Effingham, IL) |
Correspondence
Address: |
PAUL D. BIANCO: FLEIT, KAIN, GIBBONS,;GUTMAN, BONGINI, & BIANCO P.L.
21355 EAST DIXIE HIGHWAY, SUITE 115
MIAMI
FL
33180
US
|
Family ID: |
30119315 |
Appl. No.: |
11/931823 |
Filed: |
October 31, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10614352 |
Jul 7, 2003 |
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11931823 |
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09556458 |
May 3, 2000 |
6592609 |
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10614352 |
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09524397 |
Mar 13, 2000 |
6368343 |
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09556458 |
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09523442 |
Mar 10, 2000 |
6475230 |
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09524397 |
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09370865 |
Aug 9, 1999 |
6447516 |
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09523442 |
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Current U.S.
Class: |
606/232 |
Current CPC
Class: |
A61B 2017/0458 20130101;
A61B 17/0487 20130101; A61B 2017/0409 20130101; A61B 2017/0619
20130101; A61B 17/68 20130101; A61B 2017/0488 20130101; A61B
2017/0414 20130101; A61B 2017/0496 20130101; A61F 2/0811 20130101;
A61B 2017/0454 20130101; A61F 2/0805 20130101; A61B 17/0401
20130101; A61B 2017/0464 20130101 |
Class at
Publication: |
606/232 |
International
Class: |
A61B 17/04 20060101
A61B017/04 |
Claims
1. A method of connecting body tissue to a bone in a body,
comprising the steps of: piercing an aperture in the cortical layer
of the bone; connecting a suture to a fastener having a leading
end, a trailing end, an aperture near the leading end operative to
receive the suture, and a length longer than the width of the
pierced aperture; pushing the fastener, with suture attached,
through the pierced bone, in a forward direction defined as leading
end first, until the entire fastener lies within the cancellous
matter inside the bone; pulling on the suture to position the
fastener inside the bone, wherein the fastener moves in a rearward
direction and rotates about an axis having a location substantially
determined by resistance to movement in a rearwards direction by
engagement of the trailing end with cancellous matter, the location
near the leading end where force is applied, the length of the
fastener, and the width of the fastener; and attaching the suture
to the body tissue to be connected to the bone; wherein the
fastener rotates to lie beneath and substantially parallel to the
inner surface of cortical bone, whereby the suture is fastened
within the bone.
2. The method of claim 1, wherein the fastener has a tapered
leading end, and wherein said piercing step includes piercing an
aperture in the cortical layer of the bone by pushing said tapered
leading end against the bone.
3. The method of claim 2, wherein in said pulling step, the
location of the axis of rotation is further determined by a reduced
resistance of the tapered leading end to movement through
cancellous matter.
4. The method of claim 1, wherein said fastener has a second
aperture, and wherein a first portion of the suture passes through
the aperture near the leading end and a second portion of the
suture passes through the second aperture, and wherein said step of
pulling further includes pulling the first portion of the suture a
greater distance than the second portion of the suture is
pulled.
5. The method of claim 4, further including, after the step of
attaching, the step of connecting the first and second suture
portions together using the application of ultrasonic vibratory
energy.
6. The method of claim 4, further including, after the step of
attaching, the step of bonding the first and second suture portions
together by generating heat through the application of ultrasonic
vibratory energy.
7. The method of claim 4, further including, after the step of
attaching, the steps of: passing the first and second suture
portions through a retainer operative to grip the suture
portions.
8. The method of claim 7, further including, after the step of
passing, the steps of: tensioning the first and second suture
portions in a direction away from the bone; sliding the retainer
towards the bone; squeezing the retainer to grip the first and
second suture portions; applying ultrasonic vibratory energy to the
retainer; releasing the compressive force about one second after
applying ultrasonic vibratory energy; whereby the first and second
suture portions are connected at least to the retainer, and are
thereby fixed relative to each other, whereby the body tissue is
connected to the bone.
9. The method of claim 1, wherein the cancellous matter serves as a
fulcrum, and leverage is created by positioning the aperture near
the leading end.
10. The method of claim 1, wherein the fastener is fabricated from
a material selected from the group consisting of: bone, autogenic
bone, lyophilized bone, cortical bone, polymer, bioerodible
polymer, biodegradable polymer, allograft, xenograft, metal,
titanium, stainless steel.
11. The method of claim 1, wherein the sutures are polymeric.
12. The method of claim 1, wherein the body tissue to be connected
is a ligament or tendon.
13. The method of claim 1, wherein the body tissue to be connected
comprises multiple layers.
14. A method of connecting body tissue to a bone in a body,
comprising the steps of: piercing an aperture in the cortical layer
of the bone; connecting a suture to a fastener having a leading
end, a trailing end, a first aperture near the leading end, a
second aperture, and a length longer than the width of the pierced
aperture, a first suture portion passing through the first
aperture, and a second suture portion passing through the second
aperture; pushing the fastener, with suture attached, through the
pierced bone, in a forward direction defined as leading end first,
until the entire fastener lies within the cancellous matter inside
the bone; pulling the first suture portion a greater distance than
the second suture portion is pulled, thereby positioning the
fastener inside the bone, wherein the fastener moves in a rearward
direction and rotates about an axis having a location substantially
determined by resistance to movement in a rearwards direction by
engagement of the trailing end with cancellous matter, the location
near the leading end where force is applied, the length of the
fastener, and the width of the fastener; and attaching the suture
to the body tissue to be connected to the bone; wherein the
fastener rotates to lie beneath and substantially parallel to the
inner surface of cortical bone, whereby the suture is fastened
within the bone.
15. A device for installing a suture in body tissue, comprising: at
least one body tissue engaging surface operative to apply pressure
to body tissue to be sutured; a first suture engaging surface
disposed proximate said body tissue engaging surface and operative
to transmit ultrasonic vibratory energy to suture sections and
generate heat within the suture sections thereby bonding the suture
sections together; a second suture engaging surface disposed in
opposed mating and moveable relation to said first suture engaging
surface, operative to hold suture sections against said first
suture engaging surface during the transmission of ultrasonic
vibratory energy, at least one sensor connect in spaced apart
relation to said body tissue engaging surface, operative to measure
a tensioning force applied to at least one suture section; at least
one clamp connected in spaced apart relation to said body tissue
engaging surface, operative to maintain a tension upon a suture;
wherein body tissue is pressed by said at least one body tissue
engaging surface, and at least two suture sections extend away from
body tissue to be sutured, are pulled to a desired tension as
measured by said first and second sensors, are maintained in
tension by said at least one clamp, and are bonded together by
being pressed between said first and second suture engaging
surfaces.
16. The device of claim 15, further including a cutter disposed
between said first and second suture engaging surfaces and said at
least one clamp, operative to cut suture sections after the suture
sections are bonded.
17. The device of claim 15, further including at least one pulley
operative to: rotatably engage suture sections; impart a force to
said at least one sensor, proportionate to the force with which the
sutures are tensioned.
18. The device of claim 15, wherein a suture retainer is connected
to the at least two suture sections, and wherein the retainer is
pressed between said first and second suture engaging surfaces,
whereby the suture sections are bonded together in association with
the retainer.
19. The device of claim 15, wherein said at least one sensor
measures tension in each of two suture sections.
20. The device of claim 15, further including: a processing unit
connected to said at least one sensor; means cooperative with said
processor for moving said first and second suture engaging surfaces
into mating relationship, and for controlling the transmission of
ultrasonic energy from said first suture engaging surface; whereby
when a desired tension is measured by said at least one sensor,
said processing unit causes said first and second suture engaging
surfaces to move into mating relationship, and said first suture
engaging surface to transmit ultrasonic vibratory energy, thereby
bonding the suture sections.
21. The device of claim 20, further including: a cutter disposed
between said first and second suture engaging surfaces and said at
least one clamp, operative to cut suture sections after the suture
sections are bonded; means cooperative with said processor for
controlling said cutter; whereby said processor causes the suture
sections to be cut after the suture sections are bonded.
22. The device of claim 15, wherein said second suture engaging
surface is further operative to transmit ultrasonic vibratory
energy.
23. The device of claim 15, wherein the suture sections are formed
from a material selected from the group consisting of: polymer,
amorphous polymer.
24. The device of claim 15, wherein a single suture passes through
a first of said at least one clamp, past said first suture engaging
surface, into the body tissue, out of the body tissue, past said
second suture engaging surface, and through a second of said at
least one clamp.
25. The device of claim 15, wherein said at least one body tissue
engaging surface applies a predetermined pressure to the body
tissue.
26. The device of claim 15, wherein at least one of said at least
one body tissue engaging surface is threaded onto a suture and
remains in the body after the suture is installed.
27. A device for installing a suture in body tissue, comprising: a
suture tensioning member including a suture holder; a suture
tensioning coupling having first and second ends, said first end
attached to said suture tensioning member; a handle attached to the
second end of said suture tensioning coupling, operative to urge
the suture tensioning member in a direction away from the body when
said handle is moved; a suture tension indicator cooperative with
said suture tensioning coupling operative to indicate when suture
tension has reached a predetermined tension force; a body tissue
pressing member; a body tissue pressing coupling having first and
second ends, said first end attached to said body tissue pressing
member; a body tissue pressure indicator cooperative with said body
tissue pressing coupling operative to indicate when body tissue
pressure has reached a predetermined pressure force; a frame
attached to the second end of said body tissue pressing coupling,
operative to press the body tissue pressing member against the body
when said frame is moved towards the body; an ultrasonic bonding
member comprising an ultrasonic vibratory energy transmitter and a
suture support member, movable together to apply a compressive
force and ultrasonic vibratory energy to at least two suture
sections, and operative thereby to bond at least two suture
sections together, said ultrasonic bonding member disposed adjacent
to the body tissue pressing member in use; wherein in use, (a) at
least two suture sections connected to body tissue extend away from
the body and pass between said ultrasonic vibratory energy
transmitter and said suture support member and are then connected
to said suture holder, (b) said frame is pushed towards the body
with increasing force, until said body tissue pressure indicator
indicates body tissue pressure has reached a predetermined pressure
force, (c) said handle is moved with increasing force, until said
suture tension indicator indicates suture tension has reached a
predetermined tension force, and (d) said ultrasonic bonding member
is then operated to bond the at least two suture sections together,
whereby a suture is installed in the body in a reliable and
reproducible manner.
28. The device of claim 27, wherein said suture tensioning coupling
includes at least one tension resilient member, and said suture
tension indicator includes an electrical contact associated with
said at least one tension resilient member, and said body tissue
pressing coupling includes at least one pressure resilient member,
and said body tissue pressure indicator includes an electrical
contact associated with said at least one pressure resilient
member.
29. The device of claim 28, wherein said tension and pressure
resilient members are springs.
30. The device of claim 27, further including: an electronic
processor; and display means associated with said electronic
processor; wherein said suture tensioning coupling includes at
least one tension force transducer connected to said processor, and
said body tissue pressing coupling includes at least one pressure
force transducer connected to said processor, whereby force levels
of said suture tensioning coupling and said body tissue pressing
coupling are indicated, respectively, upon said display means.
31. The device of claim 30, wherein said tension and pressure force
transducers are piezoelectric force transducers.
32. The device of claim 27, further including: a cutter connected
to said frame, operative to cut at least two suture sections.
33. The device of claim 27, wherein said suture holder is selected
from the group consisting of: a pin, a clamp.
34. The device of claim 27, wherein said ultrasonic vibratory
energy is between 20 and about 70 kilohertz.
35. The device of claim 27, wherein said ultrasonic vibratory
energy transmitter and said suture support member are moved
together to apply a compressive force to the sutures for a period
longer than the period during which ultrasonic vibratory energy is
applied to the sutures.
36. The device of claim 35, wherein the compressive force is
applied to the sutures for a period of about 1 second after
ultrasonic vibratory energy is stopped.
37. The device of claim 35, wherein the at least two suture
sections are flattened from a cylindrical configuration to a
flattened configuration, and are expanded in a direction transverse
to the central axes of the suture sections.
38. The device of claim 27, wherein a suture retainer is connected
to at least two suture sections, and wherein said ultrasonic
bonding member bonds the at least two sutures together in
association with said suture retainer.
39. The device of claim 27, wherein said frame is a generally
cylindrical tube, and said handle is operative to engage fingers of
a user.
40. A method of fastening an object in an animal using ultrasonic
vibratory energy, comprising the steps of: connecting an elongated
object to body tissue; inserting a portion of the elongated object
into a passage formed of a heat moldable material in a fastener
body, the fastener body having first and second opposing sides and
formed of a heat moldable material; implanting a therapeutic object
having a surface with openings within the body; contacting the
therapeutic object surface with the first side of the fastener
body; pressing an ultrasonic vibratory energy transmitter against
the second side of the fastener body; applying ultrasonic vibratory
energy using the transmitter, generating heat in the fastener body
whereby the heat moldable material of the passage deforms to
closely conform to at least a portion of the object inserted in the
passage, and whereby the first side of the fastener body attaches
to the therapeutic object; wherein body tissue is connected to the
therapeutic object.
41. The method of claim 40, wherein the therapeutic object is an
arthroplasty component.
42. The method of claim 40, wherein the therapeutic object surface
is metal.
43. The method of claim 40, wherein the therapeutic object is a
joint implant component.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. patent
application Ser. No. 09/556,458 filed May 3, 2000 (now U.S. Pat.
No. 6,592,609), which is a continuation-in-part of: U.S. patent
application Ser. No. 09/524,397 filed Mar. 13, 2000 (now U.S. Pat.
No. 6,368,343); U.S. patent application Ser. No. 09/523,442 filed
Mar. 10, 2000 (now U.S. Pat. No. 6,475,230); and U.S. patent
application Ser. No. 09/370,865 filed Aug. 9, 1999 (now U.S. Pat.
No. 6,447,516). The benefit of the earlier filing dates of the
aforementioned applications is hereby claimed for all subject
matter common to this application and any one of the aforementioned
applications. The disclosures in the aforementioned applications
are hereby incorporated herein in their entirety by this reference
thereto.
FIELD OF THE INVENTION
[0002] The present invention relates to a new and improved method
and apparatus for securing tissue in a patient's body. The method
and apparatus may be utilized to secure hard tissue and/or soft
tissue in a patient's body.
BACKGROUND OF THE INVENTION
[0003] Anchors have previously been utilized to retain sutures in a
patient's body. The anchors have previously been formed of metal,
such as stainless steel or titanium. In addition, anchors have been
formed of biodegradable materials. Anchors have also been formed of
bone. It has previously been suggested to construct anchors in the
manner disclosed in U.S. Pat. Nos. 5,527,343; 5,534,012; 5,928,267;
and 5,989,282. The disclosures in the aforementioned patents are
hereby incorporated herein in their entirety by this reference
thereto.
[0004] It has previously been suggested that ultrasonic vibratory
energy be utilized to interconnect sections of a suture in the
manner disclosed in U.S. Pat. No. 3,513,848. This patent suggests
that the suture is initially tensioned by a surgeon or his
assistant by gripping free ends of the suture and applying the
requisite force. While the requisite force is maintained,
ultrasonic energy is applied to the segments of the suture. The
high frequency mechanical vibrations applied to the suture result
in bonding of overlapping areas on segments of the suture. It has
also been suggested that ultrasonic energy could be utilized in
connecting an elongated element with a fusible receptacle in the
manner disclosed in U.S. Pat. No. 5,964,765.
[0005] When tissue is to be secured against movement relative to a
portion of a bone, it is necessary to interconnect the bone and the
tissue. In this situation, it has been a common practice to drill a
hole which extends into or through the bone. A retaining member,
such as a pin, screw or suture anchor is positioned in the hole
after it has been drilled in the bone. The concept of utilizing a
retainer member formed of bone to anchor a suture is disclosed in
U.S. Pat. No. 5,626,612. It has also been suggested that screws,
pins, anchors and plates could be fabricated from bone in the
manner disclosed in U.S. Pat. No. 5,968,047.
SUMMARY OF THE INVENTION
[0006] The present invention relates to a method and apparatus for
use in securing soft tissue, hard tissue, or hard and soft tissue
in a patient's body. The hard tissue may be any one of the many
bones in a patient's body. The soft tissue may be any one of the
tissues in a patient's body other than the hard tissue.
[0007] The tissue may be secured by using a suture. The suture may
be connected with an anchor. When an anchor is utilized in
association with a suture, the anchor may be formed of any one of
many different materials including bone or other body tissue,
biodegradable materials, or non-biodegradable materials. The anchor
may be formed of two or more different materials.
[0008] When a suture is utilized to secure body tissue, a retainer
may be connected with the suture. Alternatively, sections of the
suture may be connected with each other.
[0009] If a suture is utilized to secure body tissue, an apparatus
may advantageously be provided to tension the suture with a
predetermined force. If a retainer is utilized in association with
the suture, the apparatus may urge the retainer toward the body
tissue with a predetermined force. The retainer may be connected
with the suture in response to detection of at least a
predetermined tension in the suture and/or the transmission of a
predetermined force to the body tissue. When the retainer is to be
eliminated, sections of the suture may be interconnected in
response to detection of a predetermined tension in the suture
and/or detection of the transmission of a predetermined force to
the body tissue.
[0010] The anchor, for some uses at least, may be formed of a
single piece of bone. A pointed end portion of the anchor may have
a surface which forms an opening in a bone or other tissue in a
patient's body. The anchor may be moved into the opening formed in
the tissue by the pointed leading end portion of the anchor.
[0011] It should be understood that in certain situations, it may
be desired to use just a suture, without an anchor, to secure the
body tissue. In these situations, a retainer may be connected with
the suture. Alternatively, sections of the suture may be directly
connected with each other. In other situations, it may be desired
to use an anchor, without a suture, to secure body tissue.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] A more complete understanding of the present invention, and
the attendant advantages and features thereof, will be more readily
understood by reference to the following detailed description when
considered in conjunction with the accompanying drawings
wherein:
[0013] FIG. 1 is an enlarged plan view of an anchor which may be
utilized in securing body tissue;
[0014] FIG. 2 is a side elevational view, taken generally along the
line 2-2 of FIG. 1, further illustrating the construction of the
anchor;
[0015] FIG. 3 is a fragmentary schematic illustration depicting, on
a reduced scale, one of the ways in which the anchor of FIGS. 1 and
2 may be positioned relative to hard and soft body tissue;
[0016] FIG. 4 is a schematic fragmentary illustration depicting one
way in which the anchor of FIG. 3 may connected with body tissue
utilizing a retainer connected with a suture;
[0017] FIG. 5 is a fragmentary schematic sectional view, generally
similar to FIG. 4, illustrating how one section of a suture is
connected with an anchor embedded in cancellous bone and extends
through soft tissue while another section of the suture is
positioned to extend around the soft tissue;
[0018] FIG. 6 is a fragmentary schematic illustration depicting the
manner in which the suture of FIG. 5 is tensioned with a
predetermined force and a connector assembly is utilized to press
soft tissue against the bone prior to utilization of the assembly
to interconnect sections of the suture;
[0019] FIG. 7 is a schematic illustration depicting the manner in
which the anchor of FIGS. 1 and 2 is positioned relative to layers
of soft body tissue prior to securing of the layers of soft body
tissue with a suture connected to the anchor;
[0020] FIG. 8 is a schematic sectional view, generally similar to
FIG. 7, illustrating the manner in which the anchor and suture
cooperate with a retainer to secure the layers of soft body
tissue;
[0021] FIG. 9 is a schematic sectional view illustrating the manner
in which the anchor and suture of FIG. 7 are utilized to
interconnect layers of soft body tissue and the manner in which
sections of the suture connected with the anchor are interconnected
utilizing ultrasonic vibratory energy;
[0022] FIG. 10 is a schematic pictorial illustration of an
apparatus for use in tensioning a suture with a predetermined
tension, applying a predetermined force against a retainer, and
connecting the retainer with the suture;
[0023] FIG. 11 is a highly schematicized illustration depicting the
manner in which the apparatus of FIG. 10 is utilized to tension a
suture with a predetermined force, apply a predetermined force
against a retainer, and connect the retainer with the suture;
and
[0024] FIG. 12 is a highly schematicized illustration of a second
embodiment of the apparatus of FIG. 11.
DETAILED DESCRIPTION OF THE INVENTION
Anchor
[0025] One specific anchor 20 constructed in accordance with the
present invention is illustrated in FIGS. 1 and 2. The anchor 20
may be utilized to secure a suture relative to body tissue in a
patient's body. However, it is contemplated that, in some
situations at least, the anchor 20 may be utilized without a
suture.
[0026] The anchor 20 is formed of a single piece of bone,
specifically, hard compact bone (cortical bone). The bone from
which the anchor 20 is formed may be autogenic bone or allogenic
bone. Alternatively, the anchor 20 may be formed of xenogenic
bone.
[0027] Although the anchor 20 may be formed of bone obtained from
many different sources, it is believed that it may be preferred to
form the anchor 20 of freeze dried bone which has been obtained
from a human cadaver. The bone may be harvested under clean
conditions and treated to achieve sterility. Of course, the bone
forming the anchor 20 could be obtained in any one of many
different manners under any one of many different conditions.
[0028] Although it is preferred to form the anchor 20 of bone, the
anchor may be formed of other materials if desired. The anchor 20
may be formed of biodegradable or non-biodegradable materials. For
example, the anchor 20 may be formed of polycaperlactone. The
anchor 20 may be formed of metal, such as titanium or stainless
steel. Alternatively, the anchor 20 may be formed of biodegradable
or bioerodible copolymers.
[0029] The anchor 20 is formed of a single piece of bone and
includes a cylindrical body portion 22 and a pointed end portion
24. The pointed end portion 24 has a conical configuration. The
cylindrical body portion 22 and pointed end portion 24 have a
common longitudinal central axis 28 which extends axially through
the anchor 20.
[0030] Although the pointed end portion 24 has a conical
configuration, the pointed end portion could have a different
configuration if desired. For example, the pointed end portion
could be wedge-shaped. Alternatively, the pointed end portion 24
could have a pyramidal configuration and be formed by the
intersection of three, four, or more surfaces. The surfaces could
be flat or concave in configuration.
[0031] It is contemplated that the anchor 20 may be used in
association with a suture. If and when the anchor 20 is to be used
with a suture, the anchor is provided with a pair of passages 30
and 32. The passages 30 and 32 have a cylindrical configuration and
extend diametrically through the cylindrical body portion 22.
Central axes of the passages 30 and 32 extend parallel to each
other and intersect the central axis 28 of the anchor 20.
[0032] The passage 30 is formed entirely in the body section 22.
However, the passage 32 is formed partially in the body section 22
and partially in the pointed end portion 34. Thus, the major
portion of the passage 32 is formed in the body portion 22.
However, a minor portion of the passage 32 extends into the pointed
end portion 24.
[0033] In the illustrated embodiment of the anchor 20, two passages
30 and 32 extend diametrically through the cylindrical body portion
22 of the anchor. However, it is contemplated that only a single
passage may be provided through the anchor. This single passage
could be skewed at an acute angle relative to the central axis 28
of the anchor 20. Alternatively, the passage could extend axially
through the anchor.
[0034] Although it is preferred to provide the anchor 20 with the
pointed leading end portion 24, it is contemplated that the anchor
20 could have a different configuration. For example, the anchor 20
could have the configuration of any one of the anchors illustrated
in U.S. Pat. No. 5,527,343 or U.S. Pat. No. 5,534,012. The
disclosures in the aforementioned U.S. Pat. Nos. 5,534,012 and
5,527,343 have been and hereby are incorporated herein in their
entirety.
[0035] In one specific embodiment of the anchor 20, intended for
use with a suture, the anchor had an overall length of
approximately 0.236 inches and a body portion 22 with a diameter of
approximately 0.072 inches. The passages 30 and 32 had diameters of
approximately 0.035 inches. Another embodiment of the anchor 20 had
an overall length of approximately 0.354 inches and a body portion
22 with a diameter of approximately 0.119 inches. The passages 30
and 32 in the specific anchor had a diameter of approximately 0.046
inches.
[0036] It should be understood that the foregoing dimensions of
specific embodiments of the anchor 20 have been set forth herein
for purposes of clarity of description. It is contemplated that the
anchor 20 will be formed with dimensions which are different than
these specific dimensions. For example, an anchor 20 intended for
use without a suture may have a length which is different than the
specific lengths previously set forth herein. Similarly, anchors
intended for use with soft body tissue may have dimensions which
are different than dimensions of anchors intended for use with hard
body tissue.
[0037] The specific embodiment of the anchor 20 described herein is
formed of bone. Specifically, the anchor 20 is formed of a single
piece of human bone. However, the anchor 20 may be formed of other
materials if desired. For example, the anchor 20 may be formed of
titanium or titanium alloys. Alternatively, the anchor 20 may be
formed of stainless steel. The anchor 20 may be formed of any one
of many known biodegradable materials. The anchor 20 may be formed
of either biodegradable or nonbiodegradable polymeric
materials.
Positioning of Anchor Relative to Body Tissue
[0038] The anchor 20 of FIGS. 1 and 2 may be utilized to secure a
suture 36 (FIG. 3) relative to body tissue. The suture 36 may be
formed of a plastic material which is a biopolymer. In one specific
embodiment of the invention, the suture 36 is formed of
polyglycolide which is commercially available under the trademark
DEXON. Polyglycolide is a crystalline material that melts at about
225.degree. Celsius. Although the suture 36 is a monofilament
suture having a continuous cylindrical outer side surface, it is
contemplated that the suture could be formed in a different manner.
For example, the suture 36 could be a cable having an interlaced
structure formed by a plurality of filaments or strands which have
been twisted, braided, twined, and/or threaded together.
[0039] It is also contemplated that the suture 36 may be formed of
a polyglycolide-based copolymer, specifically, 10/90 P-LL/G (10%
poly l-lactide and 90% glycolide) which is commercially available
under the trademark VICRYL, VICRYL is a crystalline material that
melts at about 205.degree. Celsius. VICRYL can be used for either a
monofilament or a braided suture. The suture 36 may have a
construction which is similar to the construction of the sutures
disclosed in U.S. Pat. No. 5,928,267. The aforementioned U.S. Pat.
No. 5,928,267 has been and hereby is incorporated herein in its
entirety.
[0040] The strength of the suture 36 will vary as a function of the
size of the suture. It is contemplated that the specific strength
of a particular suture size will vary depending upon the material
from which the suture is constructed and the manufacturer of the
suture. By consulting a chart, a surgeon can select a suture of a
size and strength suitable for a particular use. Thus, a relatively
large suture having substantial strength may be selected when body
tissue is to be connected with a bone or when portions of a bone
are to be interconnected by the suture. On the other hand, a
relatively small suture size having a relatively small strength may
be selected when delicate body tissue, such as stomach or
intestinal tissue is to be interconnected with the suture.
[0041] The manner in which the suture size and strength varies is
explained in the aforementioned U.S. patent application Ser. No.
09/523,442, filed Mar. 10, 2000 and entitled "Method and Apparatus
for Securing a Suture". The disclosure in the aforementioned U.S.
patent application Ser. No. 09/523,442 has been and hereby is
incorporated herein in its entirety.
[0042] In the embodiment of the invention illustrated in FIG. 3,
the anchor 20 is utilized with a suture 36. The specific anchor 20
illustrated in FIG. 3 is integrally formed as one piece of freeze
dried human bone. The anchor 20 and suture 30 are utilized to hold
soft body tissue 40 against movement relative to a portion of a
bone 44 in a human patient's body. The tissue 40 is connective
tissue, such as a ligament or tendon. However, the tissue 40 could
be other types of tissue if desired.
[0043] When the tissue 40 is to be connected with the bone 44, the
anchor 20 is utilized to initiate the formation of an opening in
the bone at a location which is free of naturally occurring
openings. Prior to formation of an opening in the bone 44 with the
anchor 20, a hard outer surface 48 is removed from a compact outer
layer 50 of bone by a decortation process. The decortation process
is performed by abrading the hard outer surface 48 on the compact
outer layer 50 of hard cortical bone to expose an imperforate inner
area 52 at a location where the anchor 20 and suture 36 are to be
utilized to connect the body tissue 40 with the bone 44. Once the
decortation process has been completed, the soft body tissue 40 is
positioned in engagement with the inner area 52 in the manner
illustrated schematically in FIG. 3. The decortation process is
optional and may be omitted if desired.
[0044] The anchor 20 is then moved through the body tissue 40 into
the bone 44. It is believed that it will be preferred to move the
anchor 20 into the bone 44 under the influence of an axial force
applied against a trailing end portion of the anchor. Since the
bone forming the anchor 20 has a relatively high compressive
strength, the anchor can be utilized to transmit relatively large
forces along the longitudinal central axis 28 (FIG. 1) of the
anchor to force the anchor into the bone 44. However, bone has a
relatively low tensile strength and can not transmit large
transverse loads. Therefore, when the anchor 20 is moved into the
bone 44 under the influence of axial force applied against a
trailing end of the anchor, there may be a tendency for the anchor
to shear or fail by a lateral buckling or fracture of the anchor
rather than by direct compression of the anchor.
[0045] In order to support the anchor 20 during movement of the
anchor into the bone 44, the anchor is advantageously inserted into
a tubular cylindrical metal sleeve or member 58 (FIG. 3). A
cylindrical pusher member 60 is received in the cylindrical sleeve
58 and is utilized to apply an axial force to a circular trailing
end surface 62 on the anchor 20. Although the sleeve and pusher
member 58 and 60 could have many different configurations and
cooperate with each other in many different manners, it may be
preferred to utilize a sleeve 58 and pusher member 60 having a
construction similar to the construction illustrated in U.S. Pat.
No. 5,948,002. The disclosure in the aforementioned U.S. Pat. No.
5,948,002 is hereby incorporated herein in its entirety by this
reference thereto. Of course, different types of devices could be
utilized to move the anchor 20 into the body tissue 40 and bone 44
if desired.
[0046] When the anchor is to be moved through the body tissue 40
into the bone 44, the pointed end portion 24 of the anchor is
aligned with the body tissue 40 at a location where the anchor is
to be moved into the body tissue. The sleeve 58 is then pressed
firmly against the body tissue 40. Although a substantial space has
been shown between the inner surface of the sleeve 58 and the
cylindrical outer side surface of the anchor 20 in FIG. 3 for
purposes of clarity of illustration, it is contemplated that there
will be a relatively snug fit of the anchor 20 and pusher member 60
with the inner side surface of the sleeve 58. However, the anchor
20 and pusher member 60 will be freely movable in an axial
direction along the sleeve 58.
[0047] The pusher member 60 is then pressed firmly against the
trailing surface 62 on the anchor 20. This force easily moves the
pointed leading end portion 24 of the anchor 20 through the soft
body tissue 40 into engagement with an imperforate surface area on
the compact outer layer 50 of the bone 44.
[0048] The anchor 20 is moved out of the tubular sleeve 58 into the
compact outer layer 50 of the bone 44 at a location which is free
of naturally occurring openings (FIG. 3). To move the anchor 20 out
of the sleeve 58 into the bone 44, the pusher member applies an
axial force against the trailing end surface 62 on the anchor 20.
The axial force applied by the pusher member 60 moves the pointed
leading end portion 24 of the anchor into the compact outer layer
50 of bone. The tubular sleeve 58 engages the cylindrical outer
side surface of the anchor 20 to support the anchor against
sidewise loading. This results in the anchor being subjected
primarily to compressive force as the anchor is moved into the bone
44.
[0049] As the anchor 20 moves into the bone 44, the material of the
compact outer layer 50 of the bone is displaced sideways by the
leading end portion 24 of the anchor 20. As the anchor 20 continues
to move into the compact outer layer 50 of the bone 44, the
material of the compact outer layer supports the anchor against
transverse loading in much the same manner in which the tubular
sleeve 58 supports the anchor. Therefore, the pusher member 60 can
apply relatively large axial force to the anchor 20 without
failure, that is, without fracture or buckling of the anchor.
[0050] The anchor 20 is utilized to initiate formation of an
opening in the compact outer layer 50 of the bone 44 at a location
which is free of openings. However, if desired, a relatively small
pilot opening could be drilled through the compact outer layer 50
of the bone 44. The anchor 20 would then be utilized to form the
small pilot opening into a larger opening through which the anchor
can pass.
[0051] The anchor 20 is moved through a desired distance into the
bone 44. In order to facilitate determination of when the anchor 20
is moved through the desired distance into the bone 44, indicia may
be provided on the pusher member 20. The indicia on the pusher
member 60 cooperates with the sleeve 58 to indicate when the anchor
20 has moved through a desired distance into the bone 44. The
application of force against the anchor 20 by the pusher member 36
is then interrupted. The manner in which the sleeve 58 and pusher
member 60 cooperate with the anchor 20 is the same as disclosed in
U.S. patent application Ser. No. 09/370,865 filed Aug. 9, 1999 by
Peter M. Bonutti and entitled "Method of Securing Tissue". The
disclosure in the aforementioned U.S. patent application Ser. No.
09/370,865 has been and hereby is incorporated herein in its
entirety.
[0052] It is contemplated that the anchor 20 may be utilized,
without the suture 36, to connect the body tissue 40 with the bone
44. When the anchor 20 is to be used in this manner, the anchor 20
will engage both the body tissue 40 and the bone 44. However, the
illustrated embodiment of the anchor 20 is intended for use with
the suture 36.
[0053] The pusher member 60 is effective to push the anchor 20
through the compact outer layer 50 of hard cortical bone into
relatively soft cancellous bone 66 which is enclosed by the hard
compact outer layer 50. As the pointed leading end portion 24 of
the anchor 20 enters the cancellous bone 66, the pointed end
portion pushes the cancellous bone 66 aside to form an opening in
the cancellous bone. The anchor moves into the cancellous bone 66
along a straight path having a longitudinal axis which is
coincident with a longitudinal central axis of the sleeve 58.
Therefore, the pointed end portion 24 of the anchor is effective to
push aside tissue forming the compact outer layer 50 and the
cancellous bone 66 as the anchor moves into the bone 44.
[0054] When the anchor has moved through a predetermined distance
into the cancellous bone 66, the anchor is pivoted from the
orientation illustrated in FIG. 3 to the orientation illustrated in
FIG. 4. Thus, after the end surface 62 on the anchor 20 has moved
past the inner side surface of the compact outer layer 50 and into
the cancellous bone 66, the orientation of the anchor 20 relative
to the bone 44 is changed by rotating the anchor through ninety
degrees (90.degree.) with a toggling action.
[0055] To initiate the toggling action, a section 70 of the suture
36 extending through the anchor passage 32 to a location outside of
the bone is tensioned. At this time, a second section 72, which
extends through the anchor passage 30, is relaxed. There is enough
friction between the section 70 of the suture and the freeze-dried
bone forming the anchor 20 to initiate a pivoting action of the
anchor.
[0056] Once this pivoting action has been initiated, the pusher
member 60 (FIG. 3) is pressed against a circular rim on the end
surface 62 and the tension in the section 70 of the suture is
increased. As the tension in the section 70 of the suture is
increased, the suture tends to slide relative to the material
forming the anchor 20. Therefore, the tension in the section 72 of
the suture 36 is increased. However, the tension in the section 70
of the suture will tend to be larger than the tension in the
section 72 of the suture.
[0057] Once the anchor 20 begins to rotate with a toggling action,
the pusher member 60 is pressed against the rim of the end surface
62 to maintain the anchor at the desired depth in the cancellous
bone 66. At the same time, the tension in the sections 70 and 72 of
the suture 36 applies torque to the anchor to rotate the anchor
about the location where the anchor engages the pusher member 60.
The anchor 20 rotates with a toggling action in the manner
disclosed in the aforementioned U.S. Pat. Nos. 5,527,343;
5,534,012; and 5,948,002. The aforementioned patents have been and
hereby are incorporated herein in their entirety.
[0058] Once the anchor 20 has pivoted to the orientation
illustrated in FIG. 4, the sections 70 and 72 of the suture 36 can
be freely moved in the passages 32 and 30 extending through the
anchor. This enables the sections 70 and 72 of the suture 36 to be
moved relative to each other so that they have the desired
length.
[0059] The anchor 20 is supported in the cancellous bone 66 in a
spaced-apart relationship with the compact outer layer 50 of bone.
The anchor 20 is entirely surrounded by a matrix of the cancellous
bone 66. The anchor 20 does not touch the compact outer layer 50 of
bone. Tension forces applied to the anchor 20 by the suture 36 are
transmitted from the outer side surface of the anchor to the
cancellous bone to hold the anchor against movement relative to the
bone 44.
[0060] The suture 36 extends through an opening 78 in the compact
outer layer 50 of bone into the soft body tissue 40. The suture
extends through the soft body tissue to a location disposed on a
side of the soft body tissue opposite from the bone 44. The suture
36 extends through the body tissue 40 along the same path which the
anchor was moved through the body tissue 40 from the position shown
in FIG. 3 to the position shown in FIG. 4. The viscoelastic nature
of the soft body tissue 40 results in closing of the opening formed
in the body tissue 40 by passage of the anchor 20 through the body
tissue. However, the sections 70 and 72 of the suture remain in the
closed passage through the body tissue 40 along which the anchor 20
previously moved.
[0061] The suture 36 may be connected with the soft body tissue in
any one of many different ways. In the embodiment of the invention
illustrated in FIG. 4, a retainer 82 is connected with the sections
70 and 72 of the suture 36. Although the sections 70 and 72 of the
suture 36 could extend straight through the retainer 82, it is
preferred to form a plurality of bends in the suture by wrapping
the suture around a portion of the retainer.
[0062] The illustrated retainer 82 has a spherical configuration
with a cylindrical passage which extends diametrically through the
center of the retainer. The sections 70 and 72 of the suture 36 may
be wrapped around the retainer 82 and passed through the passage
through the retainer a plurality of times. Thus, the section 70 of
the suture 36 extends through the passage in the retainer 82,
around the outer side surface of the retainer and back through the
passage again. The section 72 of the suture 36 also extends through
the passage in the retainer 82, around the outside of the retainer
and back through the passage in the retainer. If desired, the
retainer 82 could have a different configuration and the suture 36
could be connected with the retainer in a different manner if
desired.
[0063] After the suture 36 has been inserted through the retainer
82, the retainer 82 is moved along the sections 70 and 72 of the
suture toward the body tissue 40. As the retainer 82 is moved along
the sections 70 and 72 of the suture 36 toward the body tissue 40,
the retainer moves into engagement with the body tissue. The
sections 70 and 72 of the suture 36 are then tensioned with a
predetermined force. This predetermined tension force is
transmitted through the retainer 82 to the anchor 20. At the same
time, the retainer 82 is pressed downward against the body tissue
40 with a predetermined force.
[0064] This results in the soft body tissue 40 being compressed
against the inner area 52 on the compact outer layer 50 of bone
with a predetermined force while a predetermined tension force is
transmitted through the suture 36 to the anchor 20. In this manner,
a desired force, which has been preselected as a function of the
size of the suture 36 and the characteristics of the soft body
tissue 40 and bone 44 is applied against the body tissue and the
bone by the anchor 20 and retainer 82. Although the retainer 82
applies force against a far greater surface area on the soft body
tissue 40 than would be engaged by a knot in the suture 36, a force
distribution member or button may be placed between the retainer 82
and the upper surface of the soft body tissue.
[0065] Once the retainer 82 has been moved along the suture 36 and
is being pressed against the soft body tissue 40 with a
predetermined force while a predetermined tension is maintained in
the sections 70 and 72 of the suture 36, the suture retainer 82 is
connected with the suture 36. The suture retainer 82 may be
connected with the suture 36 in any one of many different ways.
However, the retainer 82 is connected with the suture 36 by
plastically deforming the retainer to effect a cold flowing of
material of the retainer.
[0066] Force is applied against opposite sides of the retainer 82
by a pair of force application members with a clamping action. This
force is effective to cause flowing of the material of the retainer
82 at a temperature below a transition temperature range for the
material of the retainer. The cold flowing of the material of the
retainer 82 results in a collapsing of the passage through the
retainer and a flowing of the material of the retainer around the
sections 70 and 72 of the suture. This enables the material of the
retainer 82 to bond to and obtain a firm grip on the suture 36. The
cold flowing of the material of the retainer 82 occurs at a
temperature which is below the transition temperature of the
material forming the retainer.
[0067] As the material of the retainer 82 is deformed, the material
of the retainer bonds to the suture 36. When the suture 36 is of
the cable type and formed by a plurality of interconnected
filaments or strands, the material of the retainer 82 flows around
and between the strands. The material of the retainer 82 flows
completely around portions of each individual strand and bonds to
each individual strand. In addition, the material of the retainer
82 flows around the intertwined suture strands and bonds to them as
a group. Of course, if the suture 36 is a monofilament, the
material of the retainer bonds to only the single strand or
filament.
[0068] The retainer 82 may be formed of many different materials.
However, it is believed that it will be preferred to form the
retainer 82 of a biodegradable polymer. Once biodegradable polymer
which may be utilized is polycaperlactone. Alternatively, the
retainer 82 could be formed of polyethylene oxide terephthalate or
polybutylene terephthalate. It is contemplated that other
biodegradable or bioerodible copolymers could be utilized. It is
believed that it will be preferred to form the suture 36 of the
same material as the retainer 82. Thus, the suture 36 could be
formed of any one of the materials previously suggested for forming
the retainer 82.
[0069] It is preferred to effect the cold flowing of the material
of the suture retainer 82 without the addition of heat. However, it
is contemplated that the suture retainer 82 could be heated to a
temperature which is somewhat above the temperature of the body
tissue 40. If desired, heat could be transmitted to the retainer 82
through force application members which effect plastic deformation
of the material of the retainer. When the suture 36 has a plurality
of twisted strands, flowing of the material of the retainer 82
around the strands of the suture is promoted by heating of the
retainer.
[0070] The construction of the retainer 82 and the manner in which
it cooperates with the suture 36 is the same as is disclosed in the
aforementioned U.S. patent application Ser. No. 09/523,442 filed
Mar. 10, 2000 by Peter M. Bonutti et al. and entitled "Method and
Apparatus for Securing a Suture". The disclosure in the
aforementioned application Ser. No. 09/523,442 has been and hereby
is incorporated herein in its entirety.
[0071] Although one specific retainer 82 has been described in
connection with the embodiment of the invention illustrated in FIG.
4, it is contemplated that the retainer 82 could have a different
construction if desired. For example, the retainer 82 could have
any one of the constructions disclosed in the aforementioned
application Ser. No. 09/523,442. Alternatively, the retainer 82
could have a different known construction.
Embodiment of FIGS. 5 and 6
[0072] In the embodiment of the invention illustrated in FIGS. 1-4,
the sections 70 and 72 of the suture 36 extend through the body
tissue 40 and are connected with a retainer 82. In the embodiment
of the invention illustrated in FIGS. 5 and 6, one of the sections
of the suture extends through the body tissue while the other
section of the suture extends around the outside of the body
tissue. In the embodiment of the invention illustrated in FIGS. 5
and 6, the retainer is eliminated and the sections of the suture
are connected directly to each other. Since the embodiment of the
invention illustrated in FIGS. 5 and 6 is similar to the embodiment
of the invention illustrated in FIGS. 1-4, similar terminology will
be utilized to identify similar components. It should be understood
that one or more of the features of the embodiment of the invention
illustrated in FIGS. 1-4 may be used with the embodiment of the
invention illustrated in FIGS. 5 and 6.
[0073] An anchor 100 has the same construction as the anchor 20 of
FIGS. 1 and 2. The specific anchor 100 of FIGS. 5 and 6 is
integrally formed as one piece of freeze dried human bone. The
anchor 100 is inserted through soft body tissue in the same manner
as was previously described in conjunction with the embodiment of
the invention illustrated in FIGS. 3 and 4. In addition, the anchor
100 was moved through a compact outer layer 104 of a bone 106 into
cancellous bone 108 in the same manner as was previously described
in connection with FIGS. 3 and 4. The anchor 100 is supported in
the cancellous bone 108 in a spaced-apart relationship with the
compact outer layer 104 of the bone 106.
[0074] A suture 110 extends through passages in the anchor 100. The
suture 110 may have either a cable-like or a monofilament
construction. The suture 110 may be a cable having strands formed
of any of the materials mentioned in conjunction with the suture 36
of FIGS. 3 and 4. However, the illustrated suture 110 is a
monofilament having a continuous cylindrical outer side
surface.
[0075] Sections 112 and 114 of the suture 110 are pulled through
the soft body tissue 102 and into the bone 106 as the anchor 100 is
inserted into the bone in the manner previously explained in
conjunction with the embodiment of the invention illustrated in
FIG. 3. However, in the embodiment of the invention illustrated in
FIGS. 5 and 6, it is desired to have one of the sections of the
suture extend around the outside of the soft body tissue 102 while
the other section of the suture extends through the body tissue.
Thus, a gripper, illustrated schematically at 118 in FIG. 5, grips
the section 114 of the suture 110 and pulls the section 114 of the
suture out of the soft body tissue 102 after the anchor 100 has
been positioned in the cancellous bone 108. Although the section
114 of the suture 110 is withdrawn from the soft body tissue 102,
the section 112 of the suture remains extending through the soft
body tissue in the manner illustrated schematically in FIG. 5. The
section 114 of the suture 110 is wrapped around the outside of the
body tissue and pulled into engagement with the section 112 of the
suture.
[0076] Once the sections 112 and 114 of the suture 110 have been
positioned relative to the body tissue 102, the sections 112 and
114 of the suture are tensioned with a predetermined force. At the
same time, the soft body tissue 102 is pressed against the hard
compact outer layer 104 of the bone 106 with a predetermined force.
The two sections 112 and 114 of the suture 110 are then connected
with each other to hold the soft body tissue 102 in a desired
relationship with the bone 106. If desired, a force distribution
member, such as a button, may be provided between the suture 110
and the soft body tissue 102.
[0077] An apparatus 120 for tensioning the two sections 112 and 114
of the suture 110 has been illustrated schematically in FIG. 6. The
apparatus 120 includes a pair of rotatable wheels or pulleys 122
and 124. The rotatable wheels or pulleys 122 and 124 are connected
to force measurement transducers which have an output which is
proportional to the sideward force applied to the wheels. Thus,
when the suture section 112 is tensioned, a leftward force (as
viewed in FIG. 6) is applied to the rotatable wheel 122. A
transducer connected with the wheel 122 is effective to provide an
output signal which varies as a function of the leftward force
applied to the wheel 122 by the suture 112. Of course, as the
tension in the suture increases, the sideward force applied against
the wheel 122 increases.
[0078] Although many different types of known force measuring
transducers may be utilized, a solid state force measuring
transducer may be preferred. The solid state force measuring device
may be a piezoelectric transducer using a piezoelectric crystal as
a sensitive unit. The output from the transducer is transmitted to
a controller 128.
[0079] Similarly, the wheel 124 is connected with a force measuring
transducer. The force measuring transducer connected with the wheel
124 has an output which varies as a function of the force applied
against the wheel 124 by the section 114 of the suture as the
suture is tensioned. The output from the transducer connected with
the wheel 124 is also transmitted to the controller 128.
[0080] When the output from the transducers indicates that the
desired tension is present in the sections 112 and 114 of the
suture 110, clamps 132 and 134 are activated to hold the wheels 122
and 124 against rotation and to hold the sections 112 and 114 of
the suture 110 against movement relative to the wheels. For
example, the suture section 112 is manually pulled and the wheel
122 rotated until the output from the transducer connected with the
wheel indicates that a desired tension is present in the section of
the suture. The controller 128 then activates the clamp 132 to hold
both the wheel 122 and the section 112 of the suture against
movement. This results in the desired tension being maintained in
the section 112 of the suture. Similarly, when the output from the
transducer connected with the wheel 124 indicates to the controller
128 that the desire tension is present in the section 114 of the
suture, the clamp 134 is activated to clamp the wheel 124 and
suture section 114 against movement.
[0081] In response to detecting that the desired tension is present
in both sections 112 and 114 of the suture 110, the controller 128
activates a connector assembly 140 (FIG. 6) to press the soft body
tissue 102 against the bone 106 with a predetermined force. In
response to detecting that the desired tension is present in the
sections 112 and 114 of the suture and that the soft body tissue
102 is being pressed against the bone 106 with a desired force, the
controller 128 affects operation of the connector assembly 140 to
connect the sections 112 and 114 of the suture 110 together.
[0082] When the controller detects that the desired tension is
present in the sections 112 and 114 of the suture 110, the
controller activates an actuator (not shown) to press members 142
and 144 in the connector assembly 140 downward against the body
tissue 102 with a predetermined force. While the body tissue 102 is
being urged downward with a predetermined force and while a desired
tension is being maintained in the sections 112 and 114 of the
suture 110, the connector assembly 140 is operated to interconnect
the sections 112 and 114 of the suture. The sections 112 and 114 of
the suture may be interconnected with a retainer having the same
construction as the retainer 82 of FIG. 4. Alternatively, the
sections 112 and 114 of the suture may be bonded together.
Regardless of how the suture sections are interconnected, a force
distribution member may be provided.
[0083] To effect a bonding of the sections 112 and 114 of the
suture together, the member 142 functions as an anvil and the
member 144 functions as a horn to press the two sections 112 and
114 of the suture against each other and at the same time to
transmit ultrasonic vibratory energy to at least one of the two
sections of the suture. To press the sections 112 and 114 of the
suture against each and to apply ultrasonic vibratory energy to the
sections of the suture, the anvil 142 is pressed against one side
of the suture sections 112 and 114. The horn 144 is pressed against
the opposite side of the suture sections 112 and 114.
[0084] The specific force with which the horn and anvil 144 and 142
are pressed against opposite sides of the suture sections 112 and
114 will depend upon the composition of the suture sections and the
desired extent of deformation of the suture sections. When at least
one, and probably both of the suture sections 112 and 114 have been
heat softened by ultrasonic vibratory energy, the material of the
suture sections 112 and 114 is pliable. The material of the suture
sections 112 and 114 then is plastically deformed by the force
applied against the suture sections by the anvil 142 and horn
144.
[0085] In addition to the anvil 142 and horn 144, the apparatus for
transmitting ultrasonic vibratory energy to the suture sections 112
and 114 includes a generator (not shown) which changes standard
electrical power into electrical energy at the desired ultrasonic
frequency. A transducer (not shown) changes the electrical energy
into low amplitude mechanical motion or vibration. These vibrations
are transmitted to a booster which is used to increase or decrease
the amplitude of the vibrations. The vibrations are then
transmitted to the horn 144.
[0086] The ultrasonic vibratory energy transmitted to the suture
sections 112 and 114 from the horn 144 is converted into heat
energy. When this occurs, the temperature of the material forming
the portions of the suture sections 112 and 114 adjacent to the
horn 144 increases. As the temperature of the suture sections 112
and 114 increases, the material of the suture sections is heated
into the lower end portion of a transition temperature range. As
the material of the suture sections 112 and 114 is heated into the
transition temperature range, the material softens and becomes
pliable. However, the material of the suture sections 112 and 114
does not melt and retains sufficient strength to enable the desired
tension to be transmitted through the suture sections.
[0087] The somewhat softened material of the heated portions of the
suture sections 112 and 114 are pressed together and bond to each
other. The materials of the suture sections 112 and 114 are
chemically compatible so that a molecular bond can be established
between the suture sections. Like materials, that is materials
having chemical properties which are the same or very similar will
usually bond together. However, dissimilar materials may bond if
their melt temperatures are reasonably close and they are of like
molecular structure. Generally speaking, amorphous polymers are
readily bonded to each other.
[0088] One known source of devices for effecting an ultrasonic bond
is Dukane Corporation, Ultrasonics Division, 2900 Dukane Drive, St.
Charles, Ill. 60174. The connector assembly 140 may have a
construction similar to constructions of connector assemblies
disclosed in U.S. patent application Ser. No. 09/524,397 filed Mar.
13, 2000 by Peter M. Bonutti et al. and entitled "Method of Using
Ultrasonic Vibration to Secure Body Tissue". The disclosure in the
aforementioned application Ser. No. 09/524,397 has been and hereby
is incorporated herein in its entirety.
Embodiment of FIGS. 7 and 8
[0089] In the embodiments of the invention illustrated in FIGS.
1-6, the anchor has been utilized to secure a suture relative to a
bone in a human patient's body. In the embodiment of the invention
illustrated in FIGS. 7 and 8, an anchor is utilized to secure a
suture relative to soft body tissue in a human patient's body.
Since the embodiment of the invention illustrated in FIGS. 7 and 8
is similar to the embodiment of the invention illustrated in FIGS.
1-6, similar terminology will be utilized to identify similar
components.
[0090] In the embodiment of the invention illustrated in FIGS. 7
and 8, a relatively thick layer of soft body tissue, designated by
numeral 150, and a thin layer of soft body tissue, designated by
numeral 152, are to be interconnected by a tissue securing system
154. The tissue securing system 154 (FIG. 8) includes an anchor 158
which is connected with a retainer 160 by a suture 162. Although
only a single tissue securing system has been disclosed in
association with the layers 150 and 152 of soft human body tissue,
it is contemplated that a plurality of tissue securing systems
could be associated with the layers of human body tissue. The
tissue securing systems may be positioned a precise distance from
an edge portion of the layers of human body tissue in the manner
disclosed in the aforementioned U.S. patent application Ser. No.
09/524,397 filed Mar. 13, 2000 by Peter M. Bonutti et al. and
entitled "Method of Using Ultrasonic Vibration to Secure Body
Tissue".
[0091] The anchor 158 has the same construction as the anchor 20 of
FIGS. 1 and 2. The anchor 158 is integrally formed as one piece of
freeze dried human bone. The suture 162 has the same construction
as the suture 36 of FIGS. 3 and 4. The suture 162 has a cable-like
construction with a plurality of interconnected strands formed of
the materials previously mentioned in conjunction with the suture
36. The suture 162 has a section 166 which extends from a passage
168 (FIG. 7) in the anchor 158. In addition, the suture 162 has a
section 170 which extends from a passage 172 in the anchor 158.
[0092] When the anchor 158 is to be positioned relative to the
layers 150 and 152 of soft body tissue, a pointed leading end
portion 176 is positioned in engagement with one of the layers of
body tissue. At this time, a central axis of the anchor 158 extends
perpendicular to the layer 152 of body tissue. In the embodiment of
the invention illustrated in FIG. 7, the anchor 158 is positioned
in engagement with an imperforate surface area on the thin layer
152 of body tissue. However, it is contemplated that the anchor
could be inserted from the other side of the two layers of body
tissue if desired. If this was done, the anchor 158 would initially
be positioned in engagement with an imperforate surface area on the
thick layer 150 of body tissue.
[0093] Once the anchor 158 has been positioned relative to the
layer 152 of body tissue, a force, indicated schematically at 180
in FIG. 7, is applied against a trailing end of the anchor. The
force 180 is effective to push the hard cortical bone of the anchor
158 through the two layers 152 and 150 of body tissue. Thus, the
force 180 initially presses the pointed leading end portion 176 of
the anchor 158 against the thin layer 152 of body tissue. As the
anchor 158 moves into the body tissue under the influence of the
force 180, the anchor initiates the formation of an opening in the
layer 152 of body tissue at a location which is free of openings.
The pointed leading end portion 176 of the anchor deflects body
tissue sideways to initiate formation of an opening in the layer
152.
[0094] Continued movement of the anchor 158 into the layer 152 of
body tissue moves the leading end portion 176 of the anchor into
engagement with an imperforate surface on the second or lower (as
viewed in FIG. 7) layer 150 of body tissue. The leading end portion
176 of the anchor 158 penetrates the layer 150 of body tissue and
initiates the formation of an opening under the influence of the
continuing force 180. As the anchor moves through the body tissue,
the trailing end portion of the anchor moves out of the lower (as
viewed in FIG. 7) layer 150 of body tissue. The viscoelastic
material of the body tissue resiliently closes behind the anchor
158 as it passes through the body tissue. This results in the
layers 150 and 152 of body tissue engaging the two sections 166 and
170 of the suture.
[0095] The pointed leading end portion 176 of the anchor 158 is
effective to form openings in the layers 150 and 152 of body tissue
at locations which were previously free of openings. Thus, the
leading end portion 176 of the anchor 158 moves into engagement
with an imperforate surface area on an upper or outer side of the
thin layer 152 of body tissue and initiates the formation of an
opening in the body tissue. Similarly, as the anchor 158 engages
the upper side surface of the lower layer 150 of body tissue, the
pointed leading end portion 176 initiates the formation of an
opening at an imperforate surface area on the lower layer of body
tissue. The openings formed by the anchor 158 as it moves through
the layers 150 and 152 of body tissue is closed behind the anchor
due to the viscoelastic nature of the body tissue.
[0096] The anchor 158 can be moved through the layers 150 and 152
of body tissue under the influence of force applied against the
trailing end of the anchor by an inserter assembly which may
include a sleeve and pusher member, corresponding to the sleeve 58
and pusher member 60 of FIG. 3. The inserter assembly for moving
the anchor 158 may have a construction similar to any one of the
constructions disclosed in the previously mentioned U.S. Pat. No.
5,948,002 which has been and hereby is incorporated herein.
[0097] Once the anchor 158 has been moved through the layers 150
and 152 of body tissue, the section 166 of the suture 162 is
tensioned. The anchor 158 and the layers 150 and 152 of body tissue
apply sufficient friction against the section 170 of the suture 162
that tensioning the section 166 of the suture is effective to apply
a torque to the anchor which rotates it from the orientation
illustrated in FIG. 7 to the orientation illustrated in FIG. 8.
When the anchor 158 is in the orientation illustrated in FIG. 8,
the central axis of the anchor extends generally parallel to the
major side surfaces of the layers 150 and 152 of body tissue. At
this time, the two sections 166 and 170 of the suture can be
tensioned and freely moved relative to the anchor to adjust the
relative lengths of the sections 166 and 170 of the suture.
[0098] The sections 166 and 170 of the suture are connected with
the retainer 160 in the same manner as previously explained in
conjunction with the retainer 82 in FIG. 4. In the illustrated
embodiment of the retainer 160, the retainer has a spherical
configuration with a cylindrical central passage. However, it is
contemplated that the retainer 160 could have a configuration of
any one of the retainers disclosed in the aforementioned U.S.
patent application Ser. No. 09/523,442 filed Mar. 10, 2000 by Peter
M. Bonutti et al. and entitled "Method and Apparatus for Securing a
Suture". Alternatively, the retainer 160 could have a configuration
corresponding to the configuration of any other known retainer.
[0099] When the suture 162 has been positioned relative to the
retainer, the suture is tensioned with a predetermined tension
force. The retainer 160 is then moved along the sections 166 and
170 of the suture and pressed against the layers 152 and 150 of
body tissue with a predetermined force. If desired, a force
distribution member such as a button, could be provided between the
retainer 160 and the layer 152 of body tissue. Another force
distribution member could be provided between the anchor 158 and
the layer 150 of body tissue.
[0100] While the predetermined tension is maintained in the suture
162 and while the retainer 160 is urged toward the body tissue with
a predetermined force, the retainer 160 is fixedly connected with
the suture 162. The retainer 160 may be fixedly connected with the
suture by plastically deforming material of the suture retainer
with a cold flowing action or by heating the material of the
retainer and plastically deforming the material of the retainer
while it is heated into a transition temperature range for the
material of the retainer. Heating of the material of the retainer
may be accomplished by applying ultrasonic vibratory energy against
the suture retainer in the manner disclosed in the aforementioned
application Ser. No. 09/524,397, filed Mar. 13, 2000 by Peter M.
Bonutti et al. and entitled "Method of Using Ultrasonic Vibration
to Secure Body Tissue". Alternatively, the retainer 160 may be
connected with the suture 162 in any one of the ways disclosed in
the aforementioned U.S. patent application Ser. No. 09/523,442
filed Mar. 10, 2000 by Peter M. Bonutti et al. and entitled "Method
and Apparatus for Securing a Suture".
Embodiment of FIG. 9
[0101] In the embodiment of the invention illustrated in FIGS. 7
and 8, a tissue securing system 154 is utilized to interconnect
layers 150 and 152 of body tissue. A retainer 160 is associated
with a suture to apply a predetermined force against the layers 150
and 152 of body tissue and to maintain a predetermined tension in
the sections 166 and 170 of the suture. In the embodiment of the
invention illustrated in FIG. 9, the suture retainer is omitted and
the sections of the suture are connected directly to each other.
Since the embodiment of the invention illustrated in FIG. 9 is
similar to the embodiments of the invention illustrated in FIGS.
1-8, similar terminology will be utilized to identify similar
components. It should be understood that one or more of the
features of the embodiments of the invention illustrated in FIGS.
1-8 could be utilized in association with the embodiment of the
invention illustrated in FIG. 9.
[0102] In the embodiment of the invention illustrated in FIG. 9,
soft tissue layers 180 and 182 are disposed in linear apposition
with each other. A tissue securing system 184 is utilized to
interconnect the layers 180 and 182 of soft human body tissue. The
tissue securing system 184 includes an anchor 188 and a suture 190.
The anchor 188 has the same construction as the anchor 20 of FIGS.
1 and 2. The specific anchor 188 illustrated in FIG. 9 is formed as
one piece of freeze dried human bone. The suture 190 has the same
construction as the suture 36 of FIGS. 3 and 4.
[0103] The suture 190 is connected with the anchor in the same
manner as previously described in conjunction with the embodiment
of the invention illustrated in FIGS. 7 and 8. The suture 190 has
sections 192 and 194 which extend from passages 196 and 198 through
the layers 180 and 182 of body tissue. In the embodiment of the
invention illustrated in FIG. 9, a force distribution member or
button 196 is provided adjacent to the upper (as viewed in FIG. 9)
major side surface of the layer 180 of tissue. The force
distribution member 198 distributes force transmitted from the
suture 190 over a relatively large area on the layer 180 of
tissue.
[0104] The two sections 192 and 194 of the suture are tensioned
with a predetermined tension force. The force distribution member
196 is pressed against the layer 180 of body tissue with a
predetermined force. While the predetermined tension is maintained
in the suture 190 and while the force distribution member 196 is
pressed against the layer 180 of tissue with a predetermined force,
the two sections 192 and 194 of the suture 190 are bonded to each
other by a connector assembly 200.
[0105] The connector assembly 200 may have the same construction as
previously described in conjunction with the embodiment of the
invention illustrated in FIG. 6. Of course, the connector assembly
200 may have a construction which is different than the
construction of the connector assembly 140 of FIG. 6. If desired,
the two sections 192 and 194 of the suture 190 may be tensioned
with a predetermined force by an apparatus having the same
construction as the apparatus 120 of FIG. 6. It should be
understood that the two sections 192 and 194 of the suture 190 may
be tensioned in a different manner if desired. For example, the
suture sections 192 and 194 could be manually tightened without
using the apparatus 120 of FIG. 6.
[0106] The connector assembly 200 includes an anvil 202 which is
pressed against one side of the sections 192 and 194 of the suture
190. A horn 204 is pressed against the opposite sides of the
sections 192 and 194 of the suture 190. While the horn and anvil
202 and 204 are being pressed against opposite sides of the
sections 192 and 194 of the suture 190, ultrasonic vibratory energy
is transmitted from the horn 204 to at least one of the sections of
the suture. The ultrasonic vibratory energy transmitted from the
horn 204 to the sections 192 and 194 of the suture 190 is effective
to heat the material of the sections of the suture into their
transition temperature range as the sections of the suture are
pressed against each other.
[0107] When the sections of the suture have been heated into their
transition temperature range, they are bonded to each other. The
extent to which the sections 192 and 194 of the suture 190 are
heated is sufficient to soften the material of the suture. However,
the sections 192 and 194 of the suture are not heated to a
temperature which is so great as to impair the strength of the
suture 190. This enables the desired tension force to continue to
be transmitted through the sections 192 and 194 of the suture 190
as they are bonded to each other by the anvil 202 and horn 204 of
the connector assembly 200. The manner in which the connector
assembly 200 interconnects the sections 192 and 194 of the suture
190 is the same as is disclosed in the aforementioned U.S. patent
application Ser. No. 09/524,397 filed Mar. 13, 2000 by Peter M.
Bonutti et al. and entitled "Method of Using Ultrasonic Vibration
to Secure Body Tissue".
Embodiment of FIGS. 10 and 11
[0108] In the embodiments of the invention illustrated in FIGS.
1-9, a suture is tensioned with a desired force and a desired force
is transmitted to body tissue before a retainer is connected with
the suture (FIGS. 4 and 8) or sections of the suture are connected
together (FIGS. 6 and 9). An apparatus for use in tensioning the
suture and effecting the transmittal of force to body tissue is
illustrated in FIGS. 10 and 11. Although the apparatus of FIGS. 10
and 11 is advantageously used with a retainer, the apparatus may be
used without a retainer if desired. Since the embodiment of the
invention illustrated in FIGS. 10 and 11 is similar to the
embodiments of the invention illustrated in FIGS. 1-9, similar
terminology will be utilized to identify similar components. It
should be understood that one or more features of the embodiments
of the invention illustrated in FIGS. 1-9 may be used with the
embodiment of the invention illustrated in FIGS. 10 and 11.
[0109] An apparatus 220 (FIGS. 10 and 11) is utilized to secure a
suture 222 (FIG. 11) relative to body tissue. The suture 222 may
have the same construction as the suture 36 if FIGS. 3 and 4. The
specific suture 222 is a cable with a plurality of interconnected
strands or filaments. However, the suture 222 could be formed of a
single strand if desired.
[0110] In the embodiment of the invention illustrated in FIG. 11,
the body tissue includes soft body tissue 224 and bone 226. The
bone 226 includes a compact outer layer 228 which encloses
cancellous bone 230. Although the apparatus 220 has been
illustrated in FIG. 11 in association with soft body tissue 224 and
bone 226, it is contemplated that the apparatus 220 could be
utilized in association with just soft tissue in the manner
illustrated in FIG. 8. Alternatively, the apparatus 220 could be
utilized with just hard tissue. Thus, the apparatus 220 could be
utilized with fragments of a bone or with separate bones if
desired.
[0111] The apparatus 220 includes a housing 234 (FIG. 10). In FIG.
11, the housing has been omitted and the apparatus enclosed by the
housing has been illustrated schematically. The apparatus 220 (FIG.
11) includes a suture tensioning assembly 238. The suture
tensioning assembly 238 is operable to tension the suture 222 with
a predetermined tension force.
[0112] The apparatus 220 also includes a force application assembly
242 (FIG. 11). The force application assembly 242 is operable to
apply a predetermined force to a retainer 244 to urge the retainer
toward the soft body tissue 224 and bone 226. The suture tensioning
assembly 238 is disposed in the upper end portion of the housing
234 (FIG. 10) and the force application assembly 242 is disposed in
the lower end portion of the housing.
[0113] A connector assembly 248 (FIG. 11) is provided in the lower
end portion of the housing 234 adjacent to the force application
assembly 242. The connector assembly 248 is operable to connect the
retainer 244 with the suture 242. A predetermined tension force is
applied to the suture 242 by the suture tensioning assembly 238 and
a predetermined force is transmitted from the force application
assembly 242 through the retainer 244 to the soft body tissue 224
and bone 226 when the connector assembly 248 is operated to connect
the retainer with the suture.
[0114] A trimmer assembly 252 (FIG. 11) is provided in the housing
234 (FIG. 10). The trimmer assembly 252 is disposed between the
suture tensioning assembly 238 and force application assembly 242.
The trimmer assembly 252 is operable to sever the suture 222 after
the connector assembly 248 has connected the retainer 244 with the
suture and while the predetermined tension is present in the suture
and a predetermined force is being transmitted from the retainer
through the body tissue 224.
[0115] Operation of the connector assembly 248 and trimmer assembly
252 is controlled by a microprocessor or controller 256. The
controller 256 detects when the predetermined tension is present in
the suture 222 and when the predetermined force is transmitted
through the retainer 244 to the soft body tissue 224 and bone 226.
In response to detection of the predetermined tension in the suture
222 and the transmission of the predetermined force to the retainer
244, the controller 256 initiates operation of the connector
assembly 248 to connect the retainer 244 with the suture 222.
Immediately thereafter, the controller 256 effects operation of the
trimmer assembly 252 to sever the suture 222.
[0116] In the embodiment of the invention illustrated in FIGS. 10
and 11, the controller 256 (FIG. 11) effects operation of the
connector assembly 248 when both a predetermined tension is present
in the suture 222 and a predetermined force is being transmitted
through the retainer to the body tissue 224 and bone 226. However,
it is contemplated that the apparatus 220 could be constructed in
such a manner as to have the controller 256 effect operation of the
connector assembly 248 in response to only detection of a
predetermined tension in the suture 222. Alternatively, the
controller 256 could effect operation of the connector assembly 248
in response to only detection of transmission of a predetermined
force to the retainer 244 and body tissue 224.
[0117] In the embodiment of the invention illustrated in FIGS. 10
and 11, the controller 256 (FIG. 11) is spaced from the housing 234
(FIG. 10). The controller 256 is connected with the apparatus
disposed in the housing through a cable 258. However, it is
contemplated that the controller 256 could, if desired, be mounted
on or in the housing 234.
[0118] In the embodiment of the invention illustrated in FIG. 11,
the suture 222 is connected with an anchor 260 which is embedded in
the cancellous bone 230 in a spaced apart relationship with the
compact outer layer 228 of the bone 226. The anchor 260 has the
same construction as the anchor 20 of FIGS. 1 and 2. Sections 262
and 264 of the suture 222 extend from passages in the anchor
through the compact outer layer 228 of the bone 226 and the soft
body tissue 224 to the retainer 244. The sections 262 and 264 of
the suture 222 extend through the force transmission assembly 242
and trimmer assembly 252 to the suture tensioning assembly 238.
[0119] Although the suture 222 is connected with the anchor 260 in
the embodiment of the invention illustrated in FIG. 11, it is
contemplated that the suture 222 could be connected with body
tissue in a manner other than through the use of the anchor 260.
For example, suture 222 could be connected with body tissue in any
one of the ways disclosed in the aforementioned U.S. patent
application Ser. No. 09/523,442 filed Mar. 10, 2000 by Peter M.
Bonutti et al. and entitled "Method and Apparatus for Securing a
Suture".
[0120] Of course, the suture 222 could be connected with either
hard or soft body tissue in other known ways if desired. For
example, the suture could be connected with body tissue in any one
of the ways disclosed in the aforementioned U.S. Pat. No.
5,928,267. It is contemplated that the apparatus 220 will be
utilized in association with sutures which are connected with many
different types of body tissue in many different ways.
[0121] The suture tensioning assembly 238 is operable to tension
the suture 222 with at least a predetermined tension force. The
suture tensioning assembly 238 includes a circular upper member 270
having an opening through which the sections 262 and 264 of the
suture 222 extend. The upper member 270 is movable downward
relative to the housing 234 from the uppermost position illustrated
in FIG. 10. Although the upper member 270 can move downward from
the position shown in FIGS. 10 and 11, the upper member can not
move upward from the position shown in FIGS. 10 and 11.
[0122] The sections 262 and 264 of the suture 222 are fixedly
secured to the upper member 270. In the embodiment of the invention
illustrated in FIG. 11, a pin 272 extends upward from the upper
member 270. The sections 262 and 264 of the suture 222 are tied to
the pin 272.
[0123] It should be understood that the sections 262 and 264 of the
suture 222 could be connected with the upper member 270 in a
different manner if desired. For example, the sections 262 and 264
of the suture could be locked in a V-shaped slot formed in the
upper member 270. Alternatively, a gripper assembly could be
provided on the upper member 270 to grip the sections 262 and 264
of the suture.
[0124] A circular lower member 276 in the suture tensioning
assembly 238 (FIG. 11) is connected with the upper member 270 by a
plurality of springs which have been illustrated schematically at
278 in FIG. 11. The lower member 276 is movable relative to the
housing 234. The lower member 276 can only move upward from the
position shown in FIGS. 10 and 11. When the lower member 276 moves
upward, the springs 278 are compressed.
[0125] A pair of manually engageable handles 282 and 284 (FIG. 10)
are fixedly connected with diametrically opposite sides of the
cylindrical lower member 276. The handles 282 and 284 extend
through slots in the housing 234 and are readily engaged by fingers
on the hand of a surgeon during use of the apparatus 220. The
handles 282 and 284 can be manually moved upward (as viewed in FIG.
10) to move the lower member 276 upward relative to the housing
234. The handles 282 and 284 are engagable with lower ends of the
slots in the housing to block downward movement of the lower member
276 from the position shown in FIG. 11.
[0126] In order to tension the suture 222, the sections 262 and 264
of the suture are first tied off at the pin 272. As the sections
262 and 264 of the suture 222 are tied off at the pin 272, an
initial tension force is transmitted from the suture to the upper
member 270. This initial tension force moves the upper member 270
downward and slightly compress the springs 278. The handles 282 and
284 are pressed against lower ends of the slots in the housing 234
to resist the initial tension force.
[0127] Fingers on one hand of the surgeon then apply an upwardly
directed force against the handles 282 and 284. This upwardly
directed force is applied against the springs 278 (FIG. 10) by the
lower member 276. The upwardly directed force is transmitted
through the springs 278 to the upper member 270 and the sections
262 and 264 of the suture 222. As the force applied against the
handles 282 and 284 (FIG. 10) is increased, the springs 278 are
compressed and the tension in the sections 262 and 264 of the
suture 222 is increased.
[0128] As the springs 278 are compressed, a movable contact 282
(FIG. 11) moves upward toward a second contact 284. The movable
contact 282 is fixedly connected to the lower member 276. The
second contact 284 is fixedly connected to the upper member 270.
The movable contact 282 moves upward into engagement with the
second or upper contact 284 when the springs 278 have been
compressed to a predetermined extent by movement of the lower
member 276 toward the upper member 270. When the springs 278 have
been compressed to the predetermined extent, a predetermined force
is transmitted from the lower member 276 to the upper member 270.
This predetermined force is transmitted to the sections 262 and 264
of the suture through the pin 272 connected with the upper member
270.
[0129] When the movable contact 282 engages the second contact 284
and the predetermined tension force is present in the suture 222, a
circuit is completed between conductors 286 and 288 connected with
the movable contact 282 and second contact 284. The conductors 286
and 288 are connected with the controller 256. This enables the
controller 256 to detect when the movable contact 282 engages the
second or upper contact 284 and when the predetermined tension is
present in the suture 222. The controller 256 provides a visual
and/or an audible signal to indicate to the surgeon that the
predetermined tension force is being applied to the sections 262
and 264 of the suture 222.
[0130] The force application assembly 242 is operable to apply at
least a predetermined force to the retainer 244. This predetermined
force urges the retainer toward the soft body tissue 224 and bone
226. The force transmitted from the retainer 244 to the soft body
tissue 224 is effective to compress the soft body tissue against
the bone 226.
[0131] The force application assembly 242 includes a circular lower
member 294 which is located at the lower end of the housing 234
(FIG. 10). The lower member 294 is movable upward from its
lowermost position shown in FIG. 11. The lower member 294 is
engageable with the retainer 244. The lower member 294 may have a
lower (as viewed FIG. 11) side surface which is shaped to provide a
recess in which the upper portion of the retainer 244 is received.
Thus, although the lower member 294 is illustrated in FIG. 11 as
having a flat circular lower side surface, the lower member 294
could have a concave surface with an arc of curvature which
corresponds to the arc of curvature of the spherical retainer
244.
[0132] An upper member 298 in the force application assembly 242
has a generally cylindrical configuration and is disposed in a
coaxial relationship with the lower member 294. The upper member
298 is fixedly connected with the housing 234 (FIG. 10). The lower
member 294 is axially movable relative to the housing 234. The
lower member 294 is connected with the upper member 298 by a
plurality of springs which have been illustrated schematically at
302 in FIG. 11.
[0133] An upper contact 304 is fixedly connected with the upper
member 298. A lower or movable contact 306 is connected with the
lower member 294. The upper contact 304 is connected with the
controller 256 by a conductor 310. The movable contact 306 is
connected with the controller 256 by a conductor 312.
[0134] A guide rod 313 extends between the lower member 294 in the
force application assembly 242 and the upper member 270 in the
suture tensioning assembly 238. The guide rod interconnects the
suture tensioning assembly 238 and the force application assembly
242. In addition, the guide rod guides relative movement between
the upper member 270 and lower member 276 in the suture tensioning
assembly 238 and relative movement between the upper member 298 and
lower member 294 in the force application assembly 242. Although
only a single guide rod 313 has been illustrated in FIG. 11, it
should be understood that a plurality of guide rods are provided in
the apparatus 220.
[0135] When a predetermined force is to be transmitted through the
retainer 244 to the body tissue 224 and bone 226, a knurled handle
portion 314 (FIG. 10) of the housing 234 is manually grasped. A
collar 315 may be provided adjacent to the lower end of the handle
portion 315. Force is manually applied to the housing 234 urging
the housing downward (as viewed in FIG. 11) toward the retainer
244. At the same time, an upward force is being manually applied
against the handles 282 and 284.
[0136] The downward force which is manually applied to the housing
234 is transmitted to the upper member 298 (FIG. 11) which is
fixedly connected with the housing. This downward force is
transmitted from the upper member 298 through the springs 302 to
the lower member 294. The lower member 294 transmits the force to
the retainer 244 which is pressed against the soft body tissue
224.
[0137] As the housing 234 and upper member 298 are manually urged
downward toward the retainer 244, the springs 302 (FIG. 11) are
compressed. As the springs 302 are compressed, the upper contact
304 approaches the lower contact 306. When the springs 302 have
been compressed to a predetermined extent, a predetermined force is
transmitted from the upper member 298 through the springs 302 and
lower member 294 to the retainer 244 and body tissue 224. As this
occurs, upper contact 304 engages the lower contact 306.
[0138] Engagement of the contacts 304 and 306 completes a circuit
which enables the controller 256 to detect that at least a
predetermined force has been transmitted from the force application
assembly 242 to the retainer 244 and the body tissue 224 and bone
226.
[0139] When the controller 256 detects both the presence of the
predetermined tension in the suture 222 and the application of the
predetermined force against the retainer 244, the controller
initiates operation of the connector assembly 248 to connect the
retainer with the suture. The connector assembly 248 includes a
pair of movable members 316 and 318 which are disposed adjacent to
diametrically opposite sides of the retainer 244. An actuator 320
is connected with the movable member 316. An actuator 322 is
connected with the movable member 318. The actuators 320 and 322
are connected with the controller 256 by conductors 324 and
326.
[0140] In the embodiment of the invention illustrated in FIG. 11,
the actuators 320 and 322 are operable to press the movable members
316 and 318 against opposite sides of the retainer 244 and to
effect plastic deformation of the material of the retainer 244.
Force applied against opposite sides of the retainer 244 by the
members 316 and 318 is effective to cause cold flowing of the
material of the retainer at a temperature below a transition
temperature range for the material of the retainer. The cold
flowing of the material of the retainer 244 results in a collapsing
of a passage in the retainer through which the sections 262 and 264
of the suture extend. As the passage through the retainer 244
collapses and the material of the retainer cold flows, the material
flows around the sections 262 and 264 of the suture 222. This
enables the material of the retainer 244 to bond to and obtain a
firm grip on the suture 222.
[0141] In the embodiment of the invention illustrated in FIG. 11,
the sections 262 and 264 of the suture 222 extends straight through
the passage in the retainer 244. However, if desired, the sections
262 and 264 of the suture 222 could be wrapped around the retainer.
If this was done, the force applied against the sections of the
suture and the retainer 244 would embed the suture turns around the
outside of the retainer 244 in the material of the retainer and
enhance the grip between the suture 222 and the retainer 244.
[0142] During the time in which the force application members 316
and 318 are applying clamping forces against opposite sides of the
retainer 244, the retainer is pressed against the upper side
surface of the body tissue 224 with a predetermined force. In
addition, a predetermined tension is maintained in the sections 262
and 264 of the suture 222.
[0143] In the embodiment of the invention illustrated in FIG. 11,
clamping forces have been applied against opposite sides of the
retainer 244 to cause cold flowing of the material of the retainer.
However, if desired, the connector assembly 248 could be
constructed so as to effect heating of the material of the retainer
244 by the application of ultrasonic vibratory energy to the
retainer. The frictional heat created by the ultrasonic vibratory
energy transmitted to the suture retainer 244 is effective to heat
the material of the suture retainer into a transition temperature
range to facilitate collapsing of the passage in the retainer and
to facilitate bonding of the material of the retainer with the
sections 262 and 264 of the suture 222. If the connector assembly
248 is to be constructed so as to apply ultrasonic vibratory energy
to the retainer 244, the movable member 316 could be an anvil which
engages one side of the retainer and the movable member 318 could
be a horn which applies ultrasonic vibratory energy to the
retainer.
[0144] Once the retainer 244 has been securely connected with the
sections 262 and 264 of the suture 222, the trimmer assembly 252 is
operated to sever the sections 262 and 264 of the suture. The
trimmer assembly 252 is operable to sever the sections 262 and 264
of the suture 222 at a location disposed between the suture
tensioning assembly 238 and the force application assembly 242.
Since the retainer 244 has been securely connected to the suture
before the trimmer assembly 252 is operated, the retainer is
effective to maintain the predetermined tension in the sections 262
and 264 of the suture which extend between the retainer and the
anchor 260. In addition, the retainer 244 is effective to apply the
predetermined force against the body tissue 224.
[0145] The trimmer assembly 252 includes a pair of cutter
assemblies 340 and 342. The cutter assemblies 340 and 342 are
connected with the controller 256 by conductors 344 and 346. After
completion of operation of the connector assembly 248 to connect
the retainer 244 with the sections 262 and 264 of the suture 222,
the controller 256 initiates operation of the cutter assemblies 340
and 342 in the trimmer assembly 252 to sever the sections 262 and
264 of the suture 222.
[0146] When the suture 222 (FIG. 11), anchor 260 and retainer 244
are to be utilized to secure the soft body tissue 224 with the bone
226, the suture 222 is inserted through the passages in the anchor
260 in the manner previously explained in conjunction with the
embodiment of the invention illustrated in FIGS. 1-4. When this has
been done, a pointed end portion 352 of the anchor 260 is
positioned relative to the soft body tissue 224 while the soft body
tissue is in a desired location relative to the bone 226 in the
manner illustrated schematically in FIG. 3. An inserter assembly is
then utilized to move the anchor 20 through the body tissue 224 and
into the bone 226. When the anchor has been moved to a
predetermined depth in the cancellous bone 230, the anchor is
toggled from an orientation similar to the orientation illustrated
in FIG. 3 to the orientation illustrated in FIG. 11.
[0147] Once the anchor 260 and suture 222 have been positioned
relative to the body tissue 224 and bone 226, the retainer 244 is
slid along the sections 262 and 264 of the suture into engagement
with the body tissue 224. The suture sections 262 and 264 are then
positioned in the apparatus 220 (FIG. 10). A slot 356 is formed in
the apparatus 220 to facilitate positioning of the sections 262 and
264 of the suture in the apparatus. The slot 256 extends through
the housing to central portions of the suture tensioning assembly
238 (FIG. 11), force application assembly 242, connector assembly
248, and trimmer assembly 252. Although it is believed that it will
be preferred to utilize the slot 356 to facilitate positioning of
the suture 222 relative to the apparatus 220, a passage could be
provided through the apparatus and the sections 262 and 264 of the
suture inserted through the passage.
[0148] Once the sections 262 and 264 of the suture 222 have been
positioned in the apparatus 220, the apparatus is moved along the
suture 222 into engagement with the retainer 244. While the
apparatus 220 is pressed firmly against the retainer 244, the
sections 262 and 264 of the suture are tied to the pin 272. At this
time, there will be some tension in the sections 262 and 264 of the
suture 222 and there will be some force transmitted from the force
application assembly 242 to the retainer 244. However, the tension
in the suture and the force transmitted to the retainer will be
less than a minimum desired tension and force.
[0149] In order to effect the transmission of the desired force
from the apparatus 220 through the retainer 244 to the soft body
tissue 224 and bone 226, a surgeon manually grasps the handle
portion 314 (FIG. 10) of the housing 234 with one hand and pushes
the housing toward the retainer 244 (FIG. 11). As this occurs, the
springs 302 in the force application assembly are compressed and
the contact 304 moves into engagement with the contact 306 to
indicate to the controller that the predetermined force is being
transmitted from the apparatus 220 to the retainer 244. At this
time, the controller 256 may provide a visual and/or audible
indication to the surgeon that a predetermined force has been
transmitted through the retainer 244 to the body tissue 224.
[0150] The surgeon then grasps the handles 282 and 284 (FIG. 10)
with the other hand and pulls the handles upward. As this occurs,
the springs 278 in the suture tensioning assembly 238 are
compressed and force is applied against the upper member 270 to
increase the tension in the suture sections 262 and 264. When a
predetermined tension is present in the suture sections 262 and
264, the lower contact 282 in the suture tensioning assembly 238 is
in engagement with the upper contact 284 to provide an indication
to the controller that the predetermined tension is present in the
suture. At this time, the controller 256 may provide a second
visual or audible signal to the surgeon.
[0151] When the predetermined tension is present in the sections
262 and 264 of the suture 222 and the predetermined force is being
transmitted from the retainer 244 to the soft body tissue 224 and
bone 226, the controller 256 effects operation of the connector
assembly 248 to securely connect the retainer 244 with the sections
262 and 264 of suture. After the retainer 244 has been connected
with the sections 262 and 264 of the suture, the controller 256
effects operation of the trimmer assembly 252 to sever the sections
262 and 264 of the suture. This enables the apparatus 220 to be
moved away from the body tissue 224.
Embodiment of FIG. 12
[0152] In the embodiment of the invention illustrated in FIG. 11, a
suture retainer 244 is connected with the sections 262 and 264 of
the suture 222. In the embodiment of the invention illustrated in
FIG. 12, the sections of the suture are connected to each other.
Since the embodiment of the invention illustrated in FIG. 12 is
similar to the embodiments of the invention illustrated in FIGS.
1-11, similar terminology will be utilized to identify similar
components. It should be understood that one or more features of
the embodiments of the invention illustrated in FIGS. 1-11 may be
used with the embodiment of the invention illustrated in FIG.
12.
[0153] The apparatus 420 is utilized to secure a suture 422
relative to soft body tissue 424 and a bone 426. The suture 422 may
have the same construction as the suture 36 of FIGS. 3 and 4. The
specific suture 422 is a monofilament having a continuous
cylindrical outer side surface. However, the suture 422 may be
formed a plurality of intertwined strands or filaments.
[0154] The bone 426 includes a compact outer layer 428 which
encloses cancellous bone 430. Although the suture 422 has been
illustrated schematically in FIG. 12 as being associated with soft
body tissue 424 and a bone 426, it is contemplated that the suture
could be associated with just soft body tissue or with two portions
of a bone or two bones. It should be understood that the suture 422
could be associated with body tissue in any desired way.
[0155] The apparatus 420 includes a suture tensioning assembly 438
which is operable to tension the suture 422 with a predetermined
tension force. The apparatus 420 also includes a force application
assembly 442 which is operable to transmit a predetermined force to
the soft tissue 424 and bone 426. The apparatus 420 also includes a
connector assembly 448.
[0156] The connector assembly 448 is operable to connect sections
462 and 464 of the suture with each other while a predetermined
tension force is being transmitted through the sections of the
suture and while a predetermined force is being transmitted to the
soft tissue 424 and bone 426. Thus, the connector assembly 448 is
operable to connect the two sections 462 and 464 of the suture 422
with each other while the suture tensioning assembly 438 tensions
the suture to provide a tension force of at least a predetermined
magnitude in the sections 462 and 464 of the suture. In addition,
the connector assembly 448 is operable to connect the sections 462
and 464 of the suture 422 together while the force application
assembly 442 is operable to transmit at least a predetermined force
to the soft tissue 424 and bone 426.
[0157] A trimmer assembly 452 is operable to sever the sections 462
and 464 of the suture 422 while the predetermined tension force is
present in the sections of the suture and while the predetermined
force is transmitted to the soft tissue 424.
[0158] A controller 456 effects operation of the connector assembly
448 to connect the suture sections 462 and 464 together in response
to both detection that at least a predetermined tension force is
present in the sections 462 and 462 of the suture and detection
that at least a predetermined force is being transmitted to the
soft tissue 424 and bone 426. The suture tensioning assembly 438,
force application assembly 442, connector assembly 448, and trimmer
assembly 452 are at least partially enclosed by a housing which
corresponds to the housing 234 of FIG. 10. The controller 456 is
connected with the housing by a suitable cable, corresponding to
the cable 258 of FIG. 10. However, the controller could be mounted
in or on the housing for the apparatus 420 if desired.
[0159] It should be understood that the suture tensioning assembly
438 of FIG. 12 corresponds to the suture tensioning assembly 238 of
FIG. 11. Similarly, the force application assembly 442 of FIG. 12
corresponds to the force application assembly 242 of FIG. 11. The
connector assembly 448 of FIG. 12 corresponds to the connector
assembly 248 of FIG. 11. The trimmer assembly 452 of FIG. 12
corresponds to the trimmer assembly 252 of FIG. 11.
[0160] The suture tensioning assembly 438 (FIG. 12) includes a
circular upper member 470 and a circular lower member 472. In
accordance with a feature of the embodiment of the invention
illustrated in FIG. 12, force transducers 478 interconnect the
upper and lower members 472. The force transducers 478 are
connected with the controller 456 by leads 486 and 488.
[0161] Although the force transducers 478 could have many different
constructions, it is contemplated that they may be piezoelectric
transducers having a piezoelectric crystal as a sensitive element.
The piezoelectric crystals in the force transducers 478 have
outputs which correspond to the magnitude of the force being
transmitted from the lower member 422 through the force transducers
478 to the upper member 470.
[0162] The sections 462 and 464 of the suture 422 are secured to a
pin 472 extending upward from the upper member 470. Therefore,
force transmitted from the lower member 472 to the upper member 470
is transmitted from the upper member through the pin 472 to the
suture sections 462 and 464. The output from the force transducers
478 indicates to the controller 456 when a predetermined tension
force has been transmitted from the lower member 472 through the
force transducers 478 and upper member 470 to the sections 462 and
464 of the suture 422.
[0163] A pair of handles (not shown), corresponding to the handles
282 and 284 of FIG. 10, are connected with the lower member 472.
The handles connected with the lower member 472 are manually
engageable. Force which is manually applied to the handles is
transmitted from the lower member 472 through the force transducers
478 to the upper member 470.
[0164] The force application assembly 442 is operable to transmit a
predetermined force to the soft tissue 424 and bone 426. The force
application assembly 442 includes a cylindrical lower member 494
which extends downward into engagement with a force distribution
member 496 which is disposed on the soft tissue 424. The force
distribution member or button 496 has a generally circular
configuration with a pair of passages through which the sections
462 and 464 of the suture 422 extend. If desired, the force
distribution member 496 could be eliminated.
[0165] The force application assembly 494 also includes a
cylindrical upper member 498. The upper member 498 is connected
with the housing (not shown) which encloses the apparatus 420 and
corresponds to the housing 234 of FIG. 10.
[0166] The upper member 498 is connected with the lower member 494
by a plurality of force transducers 502. The force transducers 502
are connected with the controller 456 through conductors 510 and
512. The output from the force transducers 502 corresponds to the
magnitude of the force transmitted from the upper member 498 to the
lower member 494.
[0167] Although the force transducers 502 may have many different
constructions, in one specific embodiment of the invention, the
force transducers 502 were piezoelectric transducers having a
piezoelectric crystal as the sensitive unit. However, it should be
understood that the force transducers could have any desired
construction as long as they were capable of providing an output to
the controller which would indicate when at least a predetermined
force is being transmitted from the upper member 498 to the lower
member 494 and the soft tissue 424 and bone 426.
[0168] The connector assembly 448 includes movable members 516 and
518. The movable members 516 and 518 are connected with actuators
520 and 522. The actuators 520 and 522 are connected with the
controller 456 by conductors 524 and 526.
[0169] The movable member 516 and movable member 518 extend through
slots formed in the lower member 494. Thus, the lower member 494
has a cylindrical configuration and includes radially extending
slots in which the movable members 516 and 518 are received. The
lower (as viewed in FIG. 12) end portion of the lower member 494 is
disposed in abutting engagement with the force distribution member
496 and is effective to transmit force to the force distribution
member. Although the movable members 516 and 518 have been
illustrated schematically in FIG. 12 as being spaced from the force
distribution member 496, it should be understood that the movable
members engage and slide along the force distribution member.
[0170] When the controller 456 receives an output from the
transducers 478 indicating that at least a predetermined tension is
present in the sections 462 and 464 of the suture 422 and receives
an output from the force transducers 502 indicating that at least a
predetermined force is being transmitted to the soft tissue 424 and
bone 426, the controller 456 effects operation of the connector
assembly 448 to interconnect the sections 462 and 464 of the suture
422. Thus, the controller 456 effects operation of the actuators
520 and 522 to press the members 516 and 518 against opposite sides
of the sections 462 and 464 of the suture 422. While a
predetermined clamping force is being applied against the suture
sections 462 and 464 to press them against each other, the
controller 456 effects operation of the connector assembly 448 to
connect the sections 462 and 464 of the suture 422 to each
other.
[0171] In the embodiment of the invention illustrated in FIG. 12,
the sections 462 and 464 of the suture 422 are connected to each
other by the application of pressure and ultrasonic vibratory
energy to the sections of the suture. To enable ultrasonic
vibratory energy to be transmitted to the sections of the suture,
the movable member 516 functions as an anvil and the movable member
518 functions as a horn.
[0172] The movable member or horn is 518 vibrated at a rate in
excess of 20 kilohertz. Although the horn 518 may be vibrated at
any desired frequency within a range of 20 kilohertz to 70
kilohertz, it is believed that it may be desirable to vibrate the
horn or movable member 518 at a rate which is close to or greater
than 70 kilohertz. The horn 518 is vibrated for a dwell time which
is sufficient to transmit enough ultrasonic vibratory energy to the
sections 462 and 464 of the suture to heat a portion of the
material of the sections of the suture into a transition
temperature range of the material.
[0173] To effect a heating of the material of the suture sections
462 and 464, mechanical vibrations are transmitted from the horn or
movable member 518 to an interface where the suture sections 462
and 464 are pressed against each other by the anvil 516 and horn
518. As the material of the suture sections 462 and 464 are heated
into a transition temperature range, the material loses its
rigidity and softens. However, the material of the sections 462 and
464 of the suture 422 do not melt and lose substantial tensile
strength as the material is heated.
[0174] The heated and softened material of the sections 462 and 464
of the suture 422 are flattened from a cylindrical configuration to
form thin layers which are disposed in a side-by-side relationship
and have a generally plate-like configuration. As the sections 462
and 464 of the suture are pressed together and flattened, they
expand in opposite directions transverse to the central axes of the
suture sections.
[0175] After the suture sections have been interconnected by the
connector assembly 448, a trimmer assembly 452 is operated to sever
the suture sections 462 and 464 at a location between the suture
tensioning assembly 438 and force application assembly 442. The
trimmer assembly 452 includes cutter assemblies 540 and 542 which
are connected with the controller 456 by conductors 544 and 546. A
predetermined time period after the connector assembly 448 has
interconnected the suture sections 462 and 464, the controller 456
effects operation of actuators in the cutter assemblies 540 and 542
to sever the suture sections.
CONCLUSION
[0176] In view of the foregoing description, it is apparent that
the present invention relates to a method and apparatus for use in
securing soft tissue 40, hard tissue 44, and/or hard and soft
tissue in a patient's body. The hard tissue may be any one of the
many bones in a patient's body. The soft tissue may be any one of
the tissues in a patient's body other than the hard tissue.
[0177] The tissue may be secured by using a suture 36. The suture
may be connected with an anchor 20. When the anchor 20 is utilized
in association with the suture, the anchor may be formed of any one
of many different materials including bone or other body tissue,
biodegradable materials, or non-biodegradable materials. The anchor
20 may be formed of two or more different materials.
[0178] When a suture 36 is utilized to secure body tissue 40 and
44, a retainer 82 may be connected with the suture. Alternatively,
sections 112 and 114 of the suture 110 may be connected with each
other.
[0179] If a suture 110 is utilized to secure the body tissue, an
apparatus 120, 220 or 420 may advantageously be provided to tension
the suture with a predetermined force. If a retainer 244 is
utilized in association with the suture, the apparatus 220 may urge
the retainer toward the body tissue with a predetermined force. The
retainer 244 may be connected with the suture 222 in response to
detection of at least a predetermined tension in the suture and/or
the transmission of a predetermined force to the body tissue 224.
When the retainer 244 is to be eliminated, the sections 462, 464 of
the suture 422 may be interconnected in response to detection of a
predetermined tension in the suture and/or detection of the
transmission of a predetermined force to the body tissue.
[0180] The anchor 22, for some uses at least, may be formed of a
single piece of bone. A pointed end portion 24 of the anchor may
have a surface which forms an opening in a bone or other tissue in
a patient's body. The anchor 22 may be moved into the opening
formed in the tissue by the pointed leading end portion of the
anchor.
[0181] It should be understood that in certain situations, it may
be desired to use just a suture, without an anchor, to secure the
body tissue. In these situations, a retainer 82 may be connected
with the suture. Alternatively, sections of the suture may be
directly connected with each other. In other situations, it may be
desired to use an anchor, without a suture, to secure body
tissue.
[0182] All references cited herein are expressly incorporated by
reference in their entirety.
[0183] It will be appreciated by persons skilled in the art that
the present invention is not limited to what has been particularly
shown and described herein above. In addition, unless mention was
made above to the contrary, it should be noted that all of the
accompanying drawings are not to scale. A variety of modifications
and variations are possible in light of the above teachings without
departing from the scope and spirit of the invention, which is
limited only by the following claims.
* * * * *