U.S. patent application number 16/382944 was filed with the patent office on 2021-11-11 for apparatus for fastening tissue and occluding tubular body structures.
The applicant listed for this patent is Amsel Medical Corporation. Invention is credited to Nir Lilach, Raanan Miller.
Application Number | 20210346027 16/382944 |
Document ID | / |
Family ID | 1000005925972 |
Filed Date | 2021-11-11 |
United States Patent
Application |
20210346027 |
Kind Code |
A9 |
Miller; Raanan ; et
al. |
November 11, 2021 |
APPARATUS FOR FASTENING TISSUE AND OCCLUDING TUBULAR BODY
STRUCTURES
Abstract
Apparatus and methods for occluding hollow body structures, such
as blood vessels, and for attaching tissue layers together by
providing implantable elements on opposite sides of the structure
or tissue layers and drawing the implants together to occlude the
body structure and/or bring the tissue layers together. The
implants are deliverable in a low-profile configuration and
self-expand to an enlarged configuration. The implantable elements
are delivered by transfixing the body structure, then releasing the
implants on opposite sides of the body structure and drawing the
implants together to effect an occlusion or attachment. The
implants are configured to apply oppositely directed forces to
opposite surfaces of the tissue layers at alternate,
circumferentially spaced locations and may constrain the tissue in
a serpentine pattern or in a direct clamping pattern. The implants
grip the tissue in a manner that defines a pressure zone about the
transfixion aperture that prevents leakage from the aperture. The
implants have a low profile in that they have a relatively short
axial dimension relative to their deployed diameter.
Inventors: |
Miller; Raanan; (Cambridge,
MA) ; Lilach; Nir; (Kfar Yehoshua, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Amsel Medical Corporation |
Cambridge |
MA |
US |
|
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20190231354 A1 |
August 1, 2019 |
|
|
Family ID: |
1000005925972 |
Appl. No.: |
16/382944 |
Filed: |
April 12, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15699975 |
Sep 8, 2017 |
10398445 |
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16382944 |
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15438924 |
Feb 22, 2017 |
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15699975 |
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13348416 |
Jan 11, 2012 |
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15438924 |
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14639814 |
Mar 5, 2015 |
9936955 |
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13348416 |
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14272304 |
May 7, 2014 |
10076339 |
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14639814 |
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13857424 |
Apr 5, 2013 |
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14272304 |
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16049422 |
Jul 30, 2018 |
10918391 |
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13857424 |
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61431609 |
Jan 11, 2011 |
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62408426 |
Oct 14, 2016 |
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62084989 |
Nov 26, 2014 |
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61948241 |
Mar 5, 2014 |
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61820589 |
May 7, 2013 |
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61620787 |
Apr 5, 2012 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 2017/00407
20130101; A61B 17/1285 20130101; A61B 17/122 20130101; A61B
17/12031 20130101 |
International
Class: |
A61B 17/122 20060101
A61B017/122; A61B 17/128 20060101 A61B017/128; A61B 17/12 20060101
A61B017/12 |
Claims
1. An apparatus for securing a layer of tissue to another layer of
tissue or non-tissue comprising: a distal implant comprising a
distal body and a plurality of legs which may assume (i) a
diametrically-reduced delivery configuration in which it can be
passed through the layers and (ii) a diametrically-expanded
deployed configuration in which the legs are extended radially of
the distal body; and a proximal implant, separate from the distal
implant, the proximal implant comprising a proximal body and a
plurality of legs configured to assume (i) a diametrically-reduced
delivery configuration and (ii) a diametrically-expanded deployed
configuration in which the legs are extended radially of the
proximal body; an elongate retention member attached at one end to
the distal body, the retention member having a plurality of
longitudinally spaced protrusions formed along its length, the
retention member extending through the proximal body; the proximal
implant having at least one detent formed in its body, the detent
being engageable with the protrusions on the member and being
configured to allow the proximal implant to move along the
retention member toward the distal implant but to prevent movement
along the member in a proximal direction whereby the relative
positions of the implants can be adjustably fixed; the distal
implant being deployable distally of one of the layers and the
proximal implant being deployable proximally of another layer with
the retention member transfixing the layers; whereby, with layers
disposed between the deployed implants, the proximal implant can be
advanced along the retention member to clamp and secure the layers
between the legs of the implants.
2. The apparatus as defined in claim 1 wherein when the implants
are drawn fully together in the absence of the layers, the deployed
legs of the proximal and distal implants are interdigitated.
3. The apparatus as defined in claim 2 further comprising: each of
the implants having an axis and wherein the legs of at least one of
the implants being configured so that when deployed they assume an
acute angle with respect to the axis.
4. The apparatus as defined in claim 3 wherein the legs of each of
the implants assumes an acute angle when deployed, each set of legs
defining a concavity, the concavities of the implants facing each
other.
5. The apparatus as defined in claim 1 further comprising: the
deployed legs of the implants being configured to constrain the
layers disposed between the legs in a serpentine configuration that
circumscribes the bodies of the implants.
6. The apparatus as defined in claim 1 wherein each of the implants
has an axis, the apparatus further comprising: the combined axial
length of the deployed implants, when brought into engagement with
each other along the retention member and in the absence of tissue
between the implants, being no greater than about the diameter of
the deployed legs.
7. The apparatus as defined in claim 1 further comprising: a
delivery needle having a lumen and a distal outlet; the proximal
and distal implants being slidably contained in the lumen of the
needle, in tandem and in their delivery configurations, with the
distal implant located distally of the proximal implant and with
the with the legs of the implants facing each other; a pusher tube
slidably disposed in the needle proximally of the proximal implant
and adapted to engage the proximal end of the proximal implant to
push the proximal and distal implants toward the distal outlet of
the delivery needle; the retention member extending through and
beyond the proximal implant and pusher tube to a proximal location;
whereby the loaded delivery needle can be advanced through the
layers to locate the outlet distally of the layers, the pusher tube
then can be advanced to cause the distal implant to be ejected from
the outlet and deploy, then the needle can be retracted to position
the outlet proximally of the layers and the pusher tuber can then
be advanced distally to eject the proximal implant from the outlet,
whereupon the pusher tube can be advanced distally along the
retention member to urge the proximal implant toward the distal
implant to cause the implants to clamp the layers together.
8. The apparatus as defined in claim 1 wherein the at least one
detent comprises: a tab formed in a part of the tubular body of the
proximal implant, the tab having a free end that protrudes into the
lumen of the proximal body and extends in a proximal direction, the
free end of the tab defining a gap with an opposing portion of the
tubular body, the gap presenting a slight interference fit with the
protrusions of the retention member, at least one of the tab or the
protrusions being yieldable to permit movement of the proximal
implant along the retention member only in a distal direction.
9. An apparatus for securing a layer of tissue to another layer of
tissue or non-tissue comprising: a distal implant formed from a
unitary sheet of shape memory material and comprising a central
portion and a plurality of legs extending radially of and unitary
with the central portion, the legs being configured to assume (i) a
diametrically-reduced delivery configuration in which it can be
passed through the layers and (ii) a diametrically-expanded
deployed configuration in which the legs are extended radially of
the distal body; and a proximal implant formed from a unitary sheet
of shape memory material and comprising a central portion having an
aperture formed therein and a plurality of legs extending radially
of and unitary with the central portion, the legs being configured
to assume (i) a diametrically-reduced delivery configuration in
which it can be passed through the layers and (ii) a
diametrically-expanded deployed configuration in which the legs are
extended radially of the distal body; an elongate retention member
attached at one end to the central portion of the distal body, the
retention member having a plurality of longitudinally spaced
protrusions formed along its length, the retention member extending
through an aperture in the central portion of the proximal body;
the central portion of the proximal implant having a plurality of
radial slits extending radially outward of the aperture, the slits
defining a plurality of tabs having, the free ends of which define
the aperture, the aperture presenting slight interference fit to
the protrusions, the degree of interference being such as to enable
the protrusions and aperture to enable the proximal implant to be
advanced along the retention member but to resist reverse movement
when the implants are in clamping engagement with the layers; the
distal implant being deployable distally of one of the layers and
the proximal implant being deployable proximally of another layer
with the retention member transfixing the layers; whereby, with
layers disposed between the deployed implants, the proximal implant
can be advanced along the retention member to clamp and secure the
layers between the legs of the implants.
10. The apparatus as defined in claim 9 wherein when the implants
are drawn fully together in the absence of the layers, the deployed
legs of the proximal and distal implants are interdigitated.
11. The apparatus as defined in claim 10 further comprising: each
of the implants having an axis and wherein the legs of at least one
of the implants being configured so that when deployed they assume
an acute angle with respect to the axis.
12. The apparatus as defined in claim 11 wherein the legs of each
of the implants assumes an acute angle when deployed, each set of
legs defining a concavity, the concavities of the implants facing
each other.
13. The apparatus as defined in claim 9 further comprising: the
deployed legs of the implants being configured to constrain the
layers disposed between the legs in a serpentine configuration that
circumscribes the bodies of the implants.
14. The apparatus as defined in claim 9 wherein each of the
implants has an axis, the apparatus further comprising: the
combined axial length of the deployed implants, when brought into
engagement with each other along the retention member and in the
absence of tissue between the implants, being no greater than about
the diameter of the deployed legs.
15. An apparatus for securing a layer of tissue to another layer of
tissue or non-tissue comprising: a distal implant comprising a
distal body and a plurality of legs extending from the proximal end
of the distal body, the legs being adapted to assume (i) a
diametrically-reduced delivery configuration in which the distal
implant can be passed through the layers and (ii) a
diametrically-expanded deployed configuration in which the legs are
extended radially of the distal body; and a proximal implant,
separate from the distal implant, the proximal implant comprising a
tubular proximal body and a plurality of legs extending from the
distal end of the tubular body, the legs being adapted to assume
(i) a diametrically-reduced delivery configuration and (ii) a
diametrically-expanded deployed configuration in which the legs are
extended radially of the proximal body; an elongate retention
member attached at one end to the distal body, the retention member
having a plurality of longitudinally spaced protrusions formed
along its length, the retention member extending through the
proximal body; a plurality of fingers formed integrally with and
extending proximally from the proximal end of the proximal body,
the fingers having free proximal ends that converge and define an
aperture having dimensions to present slight interference fit to
passage of the protrusions of the retention member, the fingers
being sufficiently flexible to allow the proximal implant to move
along the retention member toward the distal implant but to prevent
movement along the member in a proximal direction whereby the
relative positions of the implants can be adjustably fixed; the
distal implant being deployable distally of one of the layers and
the proximal implant being deployable proximally of another layer
with the retention member transfixing the layers; whereby, with
layers disposed between the deployed implants, the proximal implant
can be advanced along the retention member to clamp and secure the
layers between the legs of the implants.
16. The device as defined in claim 1 wherein the retention member
is elastic whereby the implants may be biased toward each other
when deployed to fasten tissue.
Description
REFERENCE TO PRIOR PATENT APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent
application Ser. No. 15/699,975 filed Sep. 8, 2018 which [0002] (i)
is a continuation of U.S. patent application Ser. No. 15/438,924
filed Feb. 22, 2017 which
[0003] (a) claims benefit of U.S. patent application Ser. No.
62/408,426, filed Oct. 14, 2016 filed Sep. 8, 2018 [0004] (ii) and
is a continuation-in-part of U.S. patent application Ser. No.
14/639,814, filed Mar. 5, 2015 which
[0005] (a) claims benefit of U.S. patent application Ser. No.
62/084,989, filed Nov. 26, 2014 [0006] (iii) and is a
continuation-in-part of pending prior U.S. patent application Ser.
No. 14/272,304, filed May 7, 2014, which
[0007] (a) claims benefit of U.S. patent application Ser. No.
61/948,241, Mar. 5, 2014 and
[0008] (b) claims benefit of U.S. patent application Ser. No.
61/820,589, filed May 7, 2013 [0009] (iv) and is a
continuation-in-part of prior U.S. patent application Ser. No.
13/857,424, filed Apr. 5, 2013 [0010] (v) and is a continuation of
U.S. patent application Ser. No. 13/348,416, filed Jan. 11,
2012
[0011] (a) which claims benefit of U.S. patent application Ser. No.
61/431,609, filed Jan. 11, 2011.
[0012] The disclosures of the ten (10) above-identified patent
applications are hereby incorporated by reference in their
entireties as if fully set forth herein.
FIELD OF INVENTION
[0013] The invention relates to methods and devices for the
occlusion of blood vessels and other tubular body structures and
for clamping tissue layers together as well as to fasten tissue to
non-tissue.
BACKGROUND
[0014] There are numerous medical conditions and procedures in
which it is desirable or necessary to occlude hollow or tubular
body organs such as, for example, blood vessels or to clamp
together layers of tissue. One such example is in the treatment of
venous complications, such as varicose veins, in which treatment
involves selective occlusion of the veins. Other ducts, vessels or
hollow body organs also may have to be obstructed or tissue layers
clamped together for a variety of reasons. It would be desirable to
provide devices and methods to effect occlusions of hollow body
organs and to secure tissue layers to each other in a manner that
that is easy and quick to apply and that has a low profile.
SUMMARY
[0015] The present invention provides a minimally invasive approach
for occluding tubular body structures such as, for example, for
treating varicose veins and other blood vessels where occlusion of
the vessel or organ is an appropriate remedy.
[0016] More particularly, the inventions comprise the provision and
use of a tissue clamp or fastener that may be used to occlude a
vessel so as to restrict blood flow through the vessel or to secure
tissue to other tissue or non-tissue structures. The device is
configured to be deployed using visualization as may be provided by
ultrasound and/or other visualization apparatus (e.g., CT, MRI,
X-ray etc.). As a result, some procedures utilizing the invention
may be provided in a physician's office with minimal local
anesthetic and effectively no post-operative care. The invention
also may be utilized in other procedures under direct visualization
(e.g., during "open" surgery) or under indirect visualization such
as during laparoscopic surgery where visualization is provided
through the use of a scope, or during percutaneous surgery where
visualization is provided through the use of imaging apparatus such
as an ultrasound imager, an X-ray imager, etc.
[0017] In one form of the invention, there is provided a tissue
fastener having two cooperative parts, including a distal component
and a proximal components (referred to herein as "implants") each
of which includes a plurality of legs configured to assume (i) a
diametrically reduced configuration for disposition within the
lumen of a deployment tube (e.g., a needle), and (ii) a
diametrically expanded configuration in which the legs are extended
radially to engage the target tissue (e.g., a blood vessel) such
that when the deployed proximal and distal implants of the expanded
fastener are brought together they can clamp tissue layers such as
the walls of a vessel to occlude it. In one aspect of the invention
the legs of the two are interdigitated when they brought together
in the absence of tissue and, in another aspect, the opposing
tissue layers are bought together by constraining them in a
serpentine pattern characterized by a series of reversing bends
that extend circumferentially about the fastener axis. In a further
aspect of the invention a clamping or occlusion device is provided
in which the tissue is transfixed but in which leakage of fluids
(e.g., blood) from the transfixion puncture is minimized.
[0018] In yet another aspect of the invention, the two parts of the
fastener, when secured together have a low profile and may be
constructed to have an axial length that is less than the diameter
defined by the expanded legs of the fastener The proximal and
distal components of the fastener are deployed separately through a
needle that is passed through tissue or other layers, first by
deploying the distal fastener on the distal side of the tissue
layers, then withdrawing the needle to the proximal side of the
layers where the proximal implant is deployed. The implants are
connected by a flexible, elongate filament-like retention member,
the distal end of which end of which is secured too the distal
implant with the proximal end extending proximally through the
proximal implant, the needle and, if used, a delivery cathetger or
the like through which the apparatus is advanced to the target
site. The filament has a plurality of protrusions formed along its
length that cooperate with a detent on the proximal implant so that
the proximal implant can be advanced along the filament in one
direction, toward the distal implant. When the implants have been
urged toward each other to clamp the tissue layers, the detent
locks in engagement with one of the protusions of the retention
member to securely lock the implants together.
DESCRIPTION OF THE DRAWINGS
[0019] The various objects and advantages of the invention will be
appreciated from the following description with reference to the
accompanying drawings in which:
[0020] FIG. 1 is an isometric illustration of the proximal and
distal implants of a two-part fastener of the invention with the
legs of the implants being in their relaxed, expanded
configuration;
[0021] FIG. 2 is sectional illustration of the proximal and distal
implants locked together and with the legs of the implants
interdigitated;
[0022] FIG. 3 is an enlarged cross section of a delivery needle
with the proximal and distal implants arranged in tandem within the
lumen of the needle and in readiness to be deployed;
[0023] FIGS. 4, 5 and 6 are sequential, diagrammatic illustrations
of the deployment of the fastener;
[0024] FIG. 7 is a side view illustrating another embodiment of the
invention;
[0025] FIG. 8 is an end view of the embodiment of FIG. 8 as seen
from the top of FIG. 8;
[0026] FIGS. 9A through 9D are diagrammatic, sequential
illustrations of another embodiment of the invention;
[0027] FIG. 10 A is a diagrammatic plan view of a fastener as seen
from the proximal side in which the legs of the proximal and distal
implants are out of registry with each other and are
interdigitated;
[0028] FIG. 10B is a sectional illustration as seen along the
circumferential line 10B of FIG. 10A showing the manner in which
the interdigitated legs of the implants are oriented and the manner
in which they constrain the tissue layers in a series of sequential
alternating and reversing serpentine bends;
[0029] FIG. 11 is a series of three photographs illustrating a
clamped, simulated blood vessel constrained in a serpentine
pattern; and
[0030] FIG. 12 is a histological photograph of a blood vessel
occluded with an interdigitated fastener and illustrating the
serpentine pattern in which the walls of the vessel were
constrained.
ILLUSTRATIVE EMBODIMENTS
[0031] FIG. 1 illustrates an embodiment of a two-part tissue
fastener 10 formed in accordance with the present invention.
Two-part fastener 10 generally comprises a distal implant 12 and a
proximal implant 14. The fastener functions by pressing and
securing tissue layers, such as the opposed walls of a blood vessel
or other hollow anatomical structure together. In one illustrative
embodiment, distal implant 12 may comprise a tubular body 16 having
a distal end 18, a proximal end, and a lumen. The tubular body 16
is formed to have a plurality of longitudinally extending slits 20D
(FIG. 3) that extend from a midportion of the body to the proximal
end of the body and that define a plurality of segments that, when
the body is in its expanded configuration will assume a plurality
of radially extending legs 22. Distal implant body 16 preferably is
formed out of an elastic material (e.g., a shape memory material
having superelastic properties such as Nitinol or superelastic
polymers, including superelastic plastics) and constructed so that
the legs 22 normally are bent and project laterally away from the
longitudinal axis of tube. They may be formed, for example, by
laser cutting a Nitinol tube and shaping it under heat treatment as
is well known in the art. Due to the elastic nature of the material
used to form distal implant body 16, legs 22 can be deformed to a
tubular, substantially linear, low profile shape (FIG. 3) so that
they can be constrained within the lumen of a delivery tube or
needle 24. However, when the constraint is removed, the elasticity
of the material of the body 16 causes legs 22 to return to their
relaxed, expanded position shown in FIG. 1.
[0032] FIGS. 1 and 2 also illustrate the proximal implant 14 that
may comprise a tubular proximal body 26 having a distal end 28, a
proximal end 30, and a lumen. Tube 26 is formed to have a plurality
of slits 20P (FIG. 3) at its distal end to define a plurality of
legs 32. One or more inwardly projecting detents 42 are formed in
tube 26 adjacent its proximal end 30. Proximal implant 14 is
preferably formed out of the same or similar material as the distal
implant and is constructed so that its legs 32 normally project
radially away from the longitudinal axis of tube 26 as shown. Legs
32 can be constrained inwardly to a low-profile configuration so
that proximal implant 14 can assume a substantially tubular
configuration along its length to be contained within the lumen of
a delivery tube such as needle 24. However, when the constraint is
removed, the elastic nature of the material causes legs 32 to
return to their expanded positions.
[0033] The distal and proximal implants 12, 14 can be arranged so
that the legs of one are interdigitated with the legs of the other
which imposes a serpentine, clamping configuration on the tissue.
Interdigitation refers to an arrangement that, when the proximal
and distal implants are brought together the legs 32 of the
proximal implant will overlie the spaces between the legs 22 of the
distal implant (or vice versa), as discussed in further detail
below. In order to bring the proximal and distal implants together
and secure them with respect to each other, an elongate retention
member 34 is provided and is secured to the distal implant. The
retention member 34, may be flexible and may be filament-like, such
as a suture or may be formed from a molded polymeric material. The
distal end of the retention member 34 may be attached to the distal
implant 12 in any of a number of ways, for example, if in the form
of a suture it may be attached by passing the distal end of the
suture through an opening in the distal end of the distal implant
and a knot (suggested at 28 in FIG. 9B) may be tied to prevent the
retention member 34 from being drawn through the opening. In a
retention member formed from a molded polymer, the distal end of
the member 34 may be formed to have a plug 36 that fits into or
against the distal end 18 of the distal implant. This retention
member 34 may be molded in the form of an elongate cord 38 integral
with the plug 36 and having a plurality of longitudinally spaced
protrusions 40 formed along its length. The retention member 34
extends proximally from the distal implant 12 through the proximal
implant 14 and through the delivery tube 24 and delivery apparatus
to a location where it can be accessed and controlled by a
clinician. The retention member 34 cooperates with one or more
detents 42 formed in the proximal implant 14 in a manner that
allows the proximal implant to be advanced distally along the
retention member 34 but precludes reverse movement. In other
embodiments, the retention member may be fabricated so as to have
some elasticity so that when the fastener 20 is deployed the
retention member 34 may be stretched slightly so that its
elasticity will bias the implants toward each other to enhance
compression of the layers.
[0034] When the tissue layers are disposed between the proximal and
distal implants and the implants are drawn together to fasten the
layers, the cooperation between the detents and one of the
protrusions locks the implants in that position. The detents 42 may
take any number of configurations, for example, by forming one or
more inwardly oriented tabs in the tubular body 26 of the proximal
implant. The detents 42 and protrusions 40 should be formed so that
the detents define a gap with respect to the dimensions and shape
of the protrusions to permit the one-way movement of the proximal
implant along the retention member described above. The protrusions
may be formed in a variety of configuration, for example only, as
conical shapes (FIGS. 1 and 2) or spheres (FIG. 3), each of which
creates a wedging action as the protrusions pass through the
detents, causing the protrusions or detents, or both, to deform
enough to allow the protusions to pass. In the form of detents
shown (FIG. 2) the free ends of the tabs 42 extend radially inward
sufficiently to prevent reverse movement of the protrusions thus
locking the implants in position.
[0035] Among the advantages of the invention is that the fastener,
when deployed has a relatively short axial dimension and a
resulting low profile. The tubular bodies of the implants only need
be long enough to provide support for the legs and contain one or
more detents. When secured together no portion of either implant
extends beyond the opposite end of the other implant. For example,
with the present invention, the axial length of the connected
implants measured from the distal end of the distal implant to the
proximal end of the proximal implant may be no greater, and
preferably less, than n the diameter defined by the radially
expanded legs of the fastener 20.
[0036] Two-part fastener 20 may be deployed using associated
installation apparatus shown, diagrammatically, in FIG. 3. The
installation apparatus includes a needle 24 loaded with the
proximal implant and distal implant 12, 14 in tandem and in
readiness to be ejected from the needle 24. The retention member 34
extends through the proximal implant, the needle 24 and is long
enough to enable the clinician to access and control the retention
member from its proximal end. Additionally, the apparatus also
includes a push tube 44 slidable within the needle and located
proximally of the proximal implant 14. The implants 12, 14 and push
tube 44 have the same outer diameter so as to fit slidably within
the lumen of the needle 24 and to enable the push tube 44 to push
the implants sequentially out of the distal end of the needle.
[0037] Two-part fastener 20 and its associated installation
apparatus are used as follows. First, hollow needle 24 carrying the
implants and push tube is passed through the skin of the patient,
through intervening tissue, and across the blood vessel layers L1,
L2 (FIGS. 4 and 5) that is to be occluded or through tissue layers
to be fastened to position the distal outlet of the needle distally
of the layers. Then the pusher tube 44 is advanced distally to push
both implants distally enough to eject the distal implant 12 on the
distal side of the tissue (FIG. 4), Upon ejection from the needle
the legs 22 of the distal implant self-deploy to their expanded
configuration. The needle containing the proximal implant and push
tube then is retracted through the tissue to locate the distal end
of the needle on the proximal side of the tissue (FIG. 5). Then,
the pusher tube 44 is advanced distally to eject the proximal
implant causing its legs 32 to self-deploy to their expanded
configuration (FIG. 5). Next, while applying tension to the
retention member 34, the pusher tube 44 is advanced distally
against the proximal end of the proximal implant to cause the
implants to be drawn together to clamp the tissue layers together
(FIG. 6). As the proximal implant is advanced over the retention
member the detent(s) 42 of the proximal implant can slip past the
protrusions 40 on the retention member 34 but are precluded from
reverse movement. It will be appreciated that the arrangement of
the retention member with its protrusions that cooperate,
ratchet-like, with the detent(s) provide an ability to draw the
implants together to engage the tissues with a variable, desired
degree of clamping force, the needle and pusher tube then can be
retracted and the tail of the retention member proximal of the
proximal implant can be severed. Thus, in the placement of the
device the vessel or tissue is pierced (transfixed).
Notwithstanding the transfixion, the interdigitated legs close the
vessel or tissue to prevent flow and, therefore, there is no or
minimal leakage of blood from the transfixion aperture. This may be
contrasted with use of staples or sutures to occlude vessels or
clamp tissue in which loss of blood through the puncture holes is a
common problem.
[0038] In practicing the invention the legs of one or both of the
implants may be arranged to extend at an acute angle to the
longitudinal axis of the implant such that the legs on one or both
of the implants collectively define a cone-like concave regions
that face each other, as is apparent from FIGS. 1 and 2 and in
which the legs are interdigitated. When tissue layers are clamped
in this manner the layers are constrained in a serpentine
configuration extending circumferentially about the longitudinal
axis of the fastener. In an interdigitated arrangement, the legs of
one of the implants are out of registry with those of the other
implant so that when viewed in plan, the legs of one implant lie
between the legs of the other. In particular, arranging the legs in
an interdigitated array is considered to allow a tubular structure
to be safely occluded in a way that avoids leakage problems
associated with staples or conventional clips (e.g., hemoclips,
Ligaclips, etc.). In an interdigitated configuration the opposing
walls of the vessel are together partially wrapped about the legs
22, 32 in alternating directions to constrain the tissue in a
serpentine configuration as seen diagrammatically in FIGS. 10A and
10B. Additionally, interdigitation provides an additional means by
which the clamping forces can be adjustably controlled. By
selecting a particular cone angle defined by the expanded legs,
coupled with the dimensions of the legs, the characteristics of the
serpentine pattern can be adjusted.
[0039] FIG. 11 shows three photographs of a two-part fastener 20
with interdigitated legs effectively clamping a simulated blood
vessel. The interdigitated legs cause serpentine ripples, or folds,
in the tissue that act to extend the effective closure, and causes
closure of the vessel well beyond the region directly contacted by
the fastener legs 22, 32. This is believed to result because the
serpentine pattern extends radially somewhat beyond the periphery
defined by the outer tips of the expanded implant legs. By way of
example but not limitation, a two-part fastener 20 having a
physical deployed diameter of 5.5 mm is able to close vessels that
are over 7 mm (and even equal or greater than 1 cm) in
diameter.
[0040] It should be understood that when an interdigitated device
is locked into engagement with tissue, the thickness or nature of
the tissue may cause the legs to flex to an extent that the degree
of overlap is reduced or the legs may no longer overlap at all.
Even when this occurs the legs of the proximal and distal implants
still apply forces to the tissue that alternate in proximal and
distal directions with the legs of the proximal implant applying
distally directed forces and the legs of the distal implant
applying proximally directed forces. With legs having sufficient
stiffness these opposed forces of the implant legs, applied
alternately at circumferentially spaced locations about the center
of the fastener, are effective to secure tissue layers together or
to occlude a lumen.
[0041] The legs 32, 22 of the proximal and distal implants 14, 12
may be beveled (or rounded) so that they do not present sharp
edges, and legs 32, 22 may be designed to separate slightly from
the tissue at the free end of each leg. This is in order to
minimize any catching or damage that may be imparted on the tissue
by legs 22, 32, whereby to minimize tearing or ripping of the
tissue. Legs 22, 32 may be provided with smooth surfaces or may be
roughened, as by chemical etching or mechanical means, so as to
enhance the imaging reflectivity of the implants, or to provide
increase tissue capture and gripping.
[0042] The two-part fastener as described may be configured to
occlude blood vessels under fluid pressures of at least 100 mm Hg
and up to 300 mm Hg. Fasteners also may be made that are capable of
resisting pressure of over 700 mm Hg.
[0043] When the two-part fastener is arranged with its legs
interdigitated, the wall thickness of the vessel to be occluded or
the tissue layers to be joined does not necessarily determine
whether an effective occlusion or attachment can be achieved. As
long as the interdigitation of the legs constrains the vessel walls
in a serpentine pattern or the forces are alternately applied in
proximal and distal directions circumferentially about the center
of the fastener, the walls of the vessel may be brought into
contact with each other sufficiently to occlude the vessel, even
when the legs 22 and legs 32 may not cross each other's plane
("overlap") regardless of the summed wall thickness of the vessel.
Thus, vessels and tissue layers of varying dimensions can be
effectively occluded or fastened. Whether and to what extent the
legs of the proximal and distal implants may overlap will depend on
the characteristics and dimensions of the anatomy to be occluded
and the configuration for the implants necessary to constrain the
tissue in a serpentine configuration.
[0044] Where legs 32, 22 of the proximal and distal implants 14, 12
are interdigitated, the serpentine constraint of the tissue layers
reduces the force needed to occlude the vessel and is considered to
be much less than the force needed to close the same vessel with a
conventional ligation clip. FIG. 12 is a photograph of a
histological section of tissue from a vessel occluded with an
interdigitated fastener and showing the serpentine pattern of the
tissue layers of the vessel walls after healing of up to 30 days.
The vessel is completely occluded and the vessel wall tissue is
compressed and adhered to itself in the serpentine configuration.
The "pie crust" or serpentine closure may be observed more clearly
as well. The arrow indicates the collapsed undulating artery. AVO
indicates the location of the interdigitating legs of two-part
fastener 20.
[0045] The two-part fastener 20 of the present invention may be
used to occlude vessels, ducts and/or to compress tissue so it is
occluded/compressed at forces less than 700 grams, while the force
required to seal off vessels or clamp tissue with a commercially
available Ligaclip are about ten times greater. The two-part
fastener 20 of the present invention can maintain operation within
the range of elasticity of the material and does not need to be
plastically deformed to realize occlusion.
[0046] FIGS. 7 and 8 illustrate, diagrammatically, an individual
proximal implant that may be made in another embodiment of the
invention. In this embodiment, the implant may be formed from a
flat sheet of heat treatable, shape memory, elastic material (e.g.,
Nitinol) and may be laser cut from the sheet in what may be in a
spider-like configuration having a central portion 50 and a
plurality of legs 52 extending radially outward from the central
portion. The central portion 50 may have a central aperture 54 and
a plurality of slits 56 that extend radially outward from the
aperture 54 to define a plurality of tabs 58, the inner ends of
which are free and define the aperture 54. The device then is heat
treated while maintaining it in a desired shape, for example, as
the concave, conical shape described above in connection with the
embodiment of FIG. 1. FIG. 7 shows this embodiment with the legs 52
constrained in parallel so that the implant can be contained in a
delivery tube, such as a needle. The distal implant (not shown) in
this embodiment may be formed in the same manner. In this
embodiment, a retention member also is employed and secured to the
distal implant in a manner similar to that described above. The
retention member, with protrusions, extends from the distal implant
proximally through the central aperture 54 to a proximal location
where the clinician can access it. The tabs 58 are flexible so that
they can flex to allow the protrusions on the retention member to
pass through as the proximal implant is advanced distally.
[0047] FIGS. 9A-9D illustrate, diagrammatically, a modified
embodiment of the invention and the sequence of its operation. In
this embodiment, a distal implant 60 and a proximal implant 62, are
provided and may be formed in the same manner as described above.
The distal implant 60 has a tubular body 64 with a plurality of
proximally extending legs 66 arranged as described above and which
can be constrained to fit in a delivery tube or needle. As with the
previously described embodiments, a retention member 67 having
longitudinally spaced protrusions 69 is secured to the distal
implant and extends in a proximal direction. The proximal implant
62 has a tubular body 68 and a plurality of distally extending legs
70 arranged in a manner as described above such that when deployed
and brought together the legs of the proximal and distal implants
may interdigitate. The proximal implant 62 also is provided with a
plurality of fingers or tabs 72 that extend from the proximal end
of the tubular body 68. The fingers 72 are arranged so that their
free ends converge as suggested in FIGS. 9B and 9C to cooperate to
define a narrow opening 74 through which the retention member may
pass (FIG. 9D). The free ends of the fingers are configured so that
the narrow opening is smaller than the protrusions on the retention
member. The fingers 72, however, are flexible and can flex as a
proximal implant is advanced distally over the protrusions in a
distal direction (FIG. 9D), allowing the protrusions to pass
through the opening. Once a protrusion has passed through the
opening, backward movement is prevented because the protrusion
abuts the distal tips of fingers (FIG. 9C).
[0048] It will be appreciated that the fasteners of the present
invention can also be used to occlude tubular and hollow structures
other than blood vessels. By way of example but not limitation, the
temporary fastener of the present invention can be used to occlude
fallopian tubes, vas deferens, ducts, as the bile duct and cystic
ducts for cholecystectomy, lymphatic vessels, including the
thoracic duct, fistula tracts, etc. The present invention can also
be used to bring, attach and/or connect at least two folds (e.g.,
two sides of the stomach, or other parts of the legs, etc.)
together so that they are connected.
[0049] In addition to occluding blood vessels the fasteners can be
used for clamping and compressing regions of resected organs so as
to reduce or stop blood flow or blood loss after surgery. For
example, the fastener may be used in solid organ resection of the
kidney or liver or other organs. Blood loss and secretion leakage
(e.g., bile, urine, etc.) can be problematic in existing solid
organ resection procedures. Average blood loss for a liver
resection is 700-120 ml. By clamping desired regions of the solid
organ with one or more fasteners, it is possible to significantly
reduce the amount of undesirable fluid loss (blood loss, secretion
leakage, etc.). The fastener can be used to apply pressure
selectively to broad areas of the organ and, additionally, may also
be used to close off selective tubular structures and vessels
connecting the organ with other regions of the body. Multiple
discrete fastener elements may be deployed across regions of the
organ. Where multiple, single, separate puncture placements of the
fastener are used, different regions of the solid organ may be
compressed to different and controllable degrees.
[0050] Although described in the context of occluding blood
vessels, the present invention may be practiced under direct
visualization (e.g., during "open" surgery) or under indirect
visualization (e.g., during laparoscopic surgery where
visualization is provided through the use of a scope, or during
percutaneous surgery where visualization is provided through the
use of imaging apparatus such as an ultrasound imager, an X-ray
imager, etc.).
[0051] The present invention can also be used to connect tissue
with other non-tissue materials, e.g., graft materials, hernia
meshes, drug delivery materials, etc.
[0052] In each of the foregoing embodiments the transfixion
aperture that is formed by the delivery needle does not tend to
leak blood (or other fluid) because the zone about the point of
transfixion where the legs cooperate to prevent fluid flow
substantially prevents fluid from reaching the aperture. Thus, the
invention may be advantageous in many situations over other
techniques in which blood loss may be problematic (e.g., staples,
sutures, etc.)
[0053] Thus, it will be appreciated that the foregoing description
provides devices and methods for occluding vessels and for clamping
tissue layers that provide advantages over prior art techniques.
Fasteners and clamps are provided that employ a pair of components
that are brought together on opposite sides of a vessel or tissue
layers to compress the vessel walls or tissue layers. The clamping
may be directly on the tissue or may be such as to constrain the
tissue layers in a serpentine pattern that is considered to occlude
or clamp with less direct compressive force on the tissue. Applying
oppositely directed forces at alternating locations on the tissue
circumferentially about the center of the fastener also may effect
occlusion or clamping. The fasteners may include pluralities of
radially extending legs or spirally oriented elements that
cooperate to effect occlusion or clamping. In each instance a
pressure zone of occlusion is formed about the point of transfixion
to prevent leakage through the transfixion aperture. Moreover,
these advantages are achieved in devices that have a low
profile.
[0054] It should be understood, however, that the foregoing
description of the invention is intended merely to be illustrative
and that other embodiments, modification and equivalents may be
apparent to those skilled in the art without departing from the
principles of the invention.
* * * * *