U.S. patent application number 10/249266 was filed with the patent office on 2003-07-24 for bioabsorbable sealant.
Invention is credited to Ahari , Frederick, Fisher , John S., Hronowski , Lucjan J.J..
Application Number | 20030139772 10/249266 |
Document ID | / |
Family ID | 24743342 |
Filed Date | 2003-07-24 |
United States Patent
Application |
20030139772 |
Kind Code |
A1 |
Fisher , John S. ; et
al. |
July 24, 2003 |
Bioabsorbable Sealant
Abstract
Openings in a mammalian body made by any medical procedure or
non-medical event are sealed with a bioabsorbable plug or sewn with
a bioabsorbable suture. In one exemplary embodiment, the plug in
dehydrated, unexpanded condition is pushed by a pushing device
through the lumen of a needle until a first part of the plug is
external to the opening and a second part is internal to the
opening. The needle is then withdrawn while the position of the
pushing device is maintained. The pushing device is then withdrawn,
leaving the plug in sealing relation to the opening. The body's
moisture causes the plug to expand to complete the sealing of the
opening, or the expansion may be caused by exposure to air, light,
or other stimulant. The opening may be formed in soft tissue,
internal organs, or hard tissue. The plug seals the flow of liquid
or gaseous biological fluids.
Inventors: |
Fisher , John S.; (
Belleair, FL) ; Ahari , Frederick; ( Tucson, AZ)
; Hronowski , Lucjan J.J.; ( Bedford, MA) |
Family ID: |
24743342 |
Appl. No.: |
10/249266 |
Filed: |
March 27, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10249266 |
Mar 27, 2003 |
|
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|
09/683,282 |
Nov 20, 200 |
|
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Current U.S.
Class: |
606/213 |
Current CPC
Class: |
A61B 2017/00575
20130101; A61B 17/064 20130101; A61P 9/00 20180101; A61B 2017/00004
20130101; A61B 2017/00601 20130101; A61B 17/0057 20130101; A61B
17/0644 20130101 |
Class at
Publication: |
606/213 |
International
Class: |
A61B 017/08 |
Claims
Claims
1. A method for plugging a hole in a mammalian heart, comprising
the steps of:inserting a guide wire through a preselected vein
until a distal free end of said guide wire extends through said
hole;introducing a delivery catheter over said guide wire until a
distal free end of said delivery catheter extends through said
hole;removing said guide wire from said delivery catheter;partially
deploying a dehydrated plug from a lumen of the delivery catheter
by employing a plunger and slightly withdrawing the delivery
catheter;applying a predetermined stimulus to said dehydrated
plug;waiting until said dehydrated plug has at least partially
expanded;completing deployment of the dehydrated plug by continuing
to withdraw the delivery catheter;whereby said hole is sealed when
said delivery catheter is fully withdrawn and said dehydrated plug
is fully expanded.
2. The method of claim 1, wherein said predetermined stimulus is
applied by natural moisture within said mammalian heart.
3. The method of claim 1, further comprising the step of
pre-hydrating said dehydrated plug before inserting said dehydrated
plug into said lumen.
4. The method of claim 1, wherein said dehydrated plug is formed of
a bioabsorbable polymer.
5. The method of claim 4, wherein said bioabsorbable polymer is a
bioabsorbable hydrogel material.
6. The method of claim 5, wherein said bioabsorbable hydrogel
material is selected from the group consisting of polypeptides
cross-linked with a compound selected from the group consisting of
formaldehyde, glutaraldehyde, and dialdehydes.
7. The method of claim 4, further comprising the step of
impregnating said bioabsorbable polymer with a therapeutic
substance to provide therapy as said bioabsorbable polymer is
bioabsorbed.
8. The method of claim 4, further comprising the step of
impregnating said bioabsorbable polymer with a growth factor to
promote healing of said hole as said bioabsorbable polymer is
bioabsorbed.
9. The method of claim 1, further comprising the step of forming
said dehydrated plug so that it has a solid, cylindrical
configuration prior to application of said predetermined stimulus
thereto so that said dehydrated plug is adapted to fit into said
lumen of said delivery catheter.
10. The method of claim 1, further comprising the steps of
impregnating said dehydrated plug with a contrasting agent to
facilitate detection of said dehydrated plug by imaging means
selected from the group of imaging means consisting of magnetic
resonance imaging, ultrasound, Doppler, and roentgenological means
including x-ray, CT scan, mammography, and fluoroscopy.
11. The method of claim 1, further comprising the step of
pre-hydrating said dehydrated plug with a suitable liquid fluid
while said dehydrated plug is positioned within said lumen of said
delivery catheter so that the time required for said dehydrated
plug to expand upon being deployed from said delivery catheter is
reduced or eliminated.
Description
Background of Invention
[0001] CROSS-REFERENCE TO RELATED DISCLOSURES
[0002] This disclosure is a divisional application claiming the
benefit of the filing date of pending U.S. patent application
entitled: "Bioabsorbable Sealant," by the same inventor, filed on
December 7, 2001, bearing Serial No. 09/683,282.
[0003] BACKGROUND OF THE INVENTION
[0004] Field of the invention
[0005] This invention relates, generally, to the medical arts. More
particularly, it relates to means for sealing openings in a
mammalian body created by any means.
[0006] Description of the prior art
[0007] Openings may be formed in a human or other mammalian body by
numerous means. Needles or other medical instruments may create
puncture or other types of openings, for example. Moreover,
electrical, ultrasound, optical instruments and the like may create
openings. Gunshot and knife wounds and numerous other events may
also cause openings to be formed.
[0008] An opening in a lung is undesirable because air leaks
therefrom and causes the lung to collapse. However, openings in
soft tissue, as well as openings in internal organs, such as the
heart, kidney, liver, etc., also require closure. Openings in
bones, cartilage, ligaments, and other hard tissue must also be
closed.
[0009] Many techniques have been developed for the surgical closing
of openings. Sutures were invented long ago, for example. One
important drawback to using sutures in some applications arises
from the fact that the needle used to sew the suture in place
typically has a diameter that is larger than the suture. Thus, if a
suture is used to close an opening in a lung, for example, air can
escape from the lung in the space that surrounds the suture, i.e.,
the space has the diameter of the needle and is not fully occupied
by the suture. This problem is addressed by applying an adhesive
over the suture; when the adhesive cures, the openings around the
suture are sealed. However, adhesives are difficult to apply and
control and require time to cure.
[0010] Another more recently developed technique for closing
openings includes the use of staples. The force required to apply
staples may result in torn tissue. One solution to this problem is
to apply an adhesive over the staples to seal the torn areas, just
as is done in connection with sutures.
[0011] Adhesive have been used to close other openings in the body
as well. Laparoscopic and endoscopic procedures, for example, may
require sophisticated instrumentation. In situ curing of adhesives
may be problematic depending upon the application, and may require
the use of curing agents and other means for cross-linking free
radicals to form the required bond. The curing agent may be air,
visible light, ultraviolet light, heat, laser beams, chemical
compounds that require mixing with one another, and so forth.
[0012] It would be advantageous therefore, if means for closing an
opening could be found that did not rely upon adhesives and curing
agents.
[0013] Numerous medical procedures and even non-medical events can
result in openings in the body that need to be sealed, as mentioned
earlier. Openings must be closed not just to stop the escape of air
from the lungs, but to also stop the escape of body fluids from
other body parts. Sealing means for closing openings are needed to
stop the flow of blood, cerebral spinal fluid, and other
fluids.
[0014] For exemplary purposes, an opening made by a biopsy needle
will be considered. In a biopsy procedure, a needle adapted to
collect tissue is inserted into a suspected lesion, usually
multiple times. When a sufficient quantity of the lesion has been
collected, it is taken to a lab for analysis.
[0015] To perform the procedure, a coaxial needle is first inserted
so that its leading end is positioned near the suspected lesion. A
biopsy needle is then inserted through the coaxial needle.
[0016] The puncture opening made by the coaxial needle may close
and heal naturally if the lesion is in soft tissue such as a
breast. However, if a lesion is in the lung, the puncture opening
made by the coaxial needle may need to be closed quickly. The use
of sutures or adhesives, or sutures and adhesives, are well-known
as already mentioned, but such techniques have limitations.
[0017] What is needed, then, is an apparatus for closing an opening
in a lung or other vascular organ as well as in soft or hard
tissue. The needed apparatus should close an opening quickly but
should not cause problems of the type associated with
adhesives.
[0018] Physicians often have a need to re-visit a surgical
procedure site to monitor a patient's recovery. However, the
sutures and adhesives now in use include no means for helping a
physician find the surgical site when a follow-up look is
desired.
[0019] Thus there is also a need for a means that would enable a
surgeon to locate a surgical site in the days, weeks, or months
following a surgical procedure.
[0020] However, in view of the prior art considered as a whole at
the time the present invention was made, it was not obvious to
those of ordinary skill in the pertinent art how the identified
needs could be fulfilled.
Summary of Invention
[0021] The long-standing but heretofore unfulfilled need for a
method and apparatus for sealing openings made by medical or
non-medical procedures in a mammalian body is now met by a new,
useful, and nonobvious invention.
[0022] A first embodiment of the invention includes a plug formed
of a preselected bioabsorbable material that expands in response to
a predetermined stimulus. The plug is sized to fit within the
opening prior to application of the predetermined stimulus to the
dehydrated plug. The plug expands upon application of the
predetermined stimulus thereto until the plug seals the opening. In
this way, the plug, when expanded, prevents flow of liquid or
gaseous fluid through the opening. The plug is gradually
bioabsorbed as natural processes heal the opening. The preselected
bioabsorbable material is a dehydrated hydrogel and the
predetermined stimulus is moisture that is naturally present in the
mammalian body.
[0023] The plug may have a solid, cylindrical configuration prior
to application of the predetermined stimulus thereto so that the
plug is adapted to fit into a lumen of a needle to facilitate
introduction of the plug into the opening.
[0024] If the plug is to be employed as a scaffold for tissue
regeneration, it may be provided in forms more suitable for that
purpose. For example, it may have a corkscrew configuration at one
end. It may also be designed to provide a mechanical anchor as
well, having a leading end that expands radially outwardly after
placement to prevent unintended outward migration of the plug.
[0025] The plug is impregnated with a contrasting agent to
facilitate detection of the plug by imaging means selected from the
group of imaging means consisting of magnetic resonance imaging,
ultrasound, Doppler, and roentgenological means including x-ray, CT
scan, mammography, and fluoroscopy.
[0026] Alternatively, the plug includes a radioactive substance
detectable by a radiation detecting means including a gamma counter
and a scintillation counter. In another alternative, the plug
includes a transmitting means adapted to transmit signals in the
electromagnetic spectrum that are detectable by receivers adapted
to receive signals in the electromagnetic spectrum.
[0027] The plug is adapted to be slideably disposed in a lumen of a
needle. A plug displacement means is adapted to abuttingly engage
and slidingly displace the plug within the lumen to a preselected
location near a distal end of the lumen. Withdrawal of the needle
coupled with maintaining the plug displacement means at said
preselected location during the withdrawal results in placement of
the plug at the preselected location. Withdrawal of the plug
displacement means does not cause displacement of the plug.
[0028] The novel material also has utility in promoting
angiogenesis in a mammalian heart. A cavity or bore is formed in a
heart and growth factor means is introduced into the bore. A
bioabsorbable plug that expands in response to a predetermined
stimulus then plugs the bore. The predetermined stimulus is applied
to the bioabsorbable plug so that the bioabsorbable plug expands
and seals the growth factor means within the bore.
[0029] The novel plug has further utility as a means for preventing
loss of spinal fluid from the thecal sac. An opening is formed at a
preselected site in the thecal sac by a biopsy needle introduced to
the preselected site through a coaxial needle. The biopsy needle is
withdrawn from the preselected site after the opening has been
formed. A delivery catheter having a dehydrated, bioabsorbable plug
formed of a preselected material that expands in response to a
predetermined stimulus positioned in its lumen is then introduced
through the coaxial needle to the preselected site. The dehydrated,
bioabsorbable plug is pushed from the lumen of the catheter into
the opening and said catheter is withdrawn from the preselected
site. The bioabsorbable plug expands upon being hydrated by natural
fluids present at the preselected site. The expansion holds the
plug in place and further serves to prevent leakage of spinal fluid
from the opening.
[0030] The novel material is not limited to plugs. For example, it
may also be formed into a cylindrical member that slideably
receives a plug. Such a cylindrical member and a plug may be used
with one another to provide a means for sealing an incision in an
artery. More particularly, a guide wire is inserted through the
incision and a lumen of an introducer sheath is placed in receiving
relation to the guide wire so that a leading end of the introducer
sheath is guided to the incision by the guide wire. The leading end
of the introducer sheath is positioned into abutting and
surrounding relation to the incision. A dehydrated, bioabsorbable
tube formed of a preselected material that expands in response to a
predetermined stimulus is pushed from a lumen of the introducer
sheath so that a leading end of the dehydrated, bioabsorbable tube
is disposed in abutting and surrounding relation to the incision.
The guide wire and the introducer sheath are then withdrawn from
the artery. The leading end of a delivery catheter having an
external diameter less than an internal diameter of the dehydrated,
bioabsorbable tube is then introduced into the lumen of the
dehydrated, bioabsorbable tube. A dehydrated, bioabsorbable plug
formed of a preselected material that expands in response to a
predetermined stimulus is positioned in a lumen of the delivery
catheter and is pushed from said lumen into the lumen of the
dehydrated, bioabsorbable tube. The delivery catheter is withdrawn
and the dehydrated, bioabsorbable plug expands within the lumen of
the dehydrated, bioabsorbable tube when contacted by natural
moisture within the blood flowing through the artery. The
dehydrated, bioabsorbable tube expands when contacted by the
natural moisture within the blood and by natural moisture within
tissue that surrounds the artery.
[0031] In another embodiment, an elongate suture is formed of a
preselected bioabsorbable material that expands in response to a
predetermined stimulus. The elongate suture is adapted to be pulled
by a needle so that the elongate suture is used to sew closed the
opening. The elongate suture has a diameter slightly less than a
diameter of the needle, there being a clearance space about the
elongate suture equal in diameter to the diameter of the needle
less the diameter of the elongate suture. The elongate suture
expands upon application of the predetermined stimulus thereto
until the elongate suture seals the clearance space. The elongate
suture, when expanded, prevents flow of liquid or gaseous fluid
through the clearance space and is gradually bioabsorbed as the
opening is healed by natural processes. The preselected
bioabsorbable material is a hydrogel and the predetermined stimulus
is moisture that is naturally present in a mammalian body. The
elongate suture may be impregnated with a contrasting agent to
facilitate its detection by imaging means selected from the group
of imaging means consisting of magnetic resonance imaging,
ultrasound, Doppler, and roentgenological means including x-ray, CT
scan, mammography, and fluoroscopy. The elongate suture may include
a radioactive substance detectable by a radiation detecting means
including a gamma counter and a scintillation counter.
Alternatively, it may include a transmitting means adapted to
transmit signals in the electromagnetic spectrum that are
detectable by receivers adapted to receive signals in the
electromagnetic spectrum. Moreover, the elongate suture may be
hollow and filled with a gaseous fluid.
[0032] A conventional suture, both bioabsorbable and
nonbioabsorbable, may be coated with a material that expands in
response to a predetermined stimulus and used in the same way as
the suture made entirely of the novel material. This type of
coating also provides a lubricious surface having a low coefficient
of friction to minimize trauma during the suturing process.
[0033] A rigid medical staple of the type used in anastomosis of
organs may also be coated with a preselected bioabsorbable material
that expands in response to a predetermined stimulus to fill the
openings made by the stapling procedure.
[0034] An important object of this invention is to provide a means
for sealing openings in a mammalian body quickly and in the absence
of conventional sutures, staples, and adhesives.
[0035] Another object is to provide a bioabsorbable means for
sealing such openings.
[0036] Another major object is to provide a marking means that
enables a physician to easily find a surgical site for follow-up
purposes.
[0037] These and other important objects, advantages, and features
of the invention will become clear as this description
proceeds.
[0038] The invention accordingly comprises the features of
construction, combination of elements, and arrangement of parts
that will be exemplified in the description set forth hereinafter
and the scope of the invention will be indicated in the claims.
Brief Description of Drawings
[0039] For a fuller understanding of the nature and objects of the
invention, reference should be made to the following detailed
description, taken in connection with the accompanying diagrammatic
drawings, in which:
[0040] Fig. 1 is a side elevational view of a biopsy needle taking
a sample from a lesion in a lung or any other soft tissue;
[0041] Fig. 2 is a view depicting the positioning of a
bioabsorbable plug in the coaxial needle of Fig. 1;
[0042] Fig. 3 is a view like that of Fig. 2, but after the coaxial
needle has been withdrawn, leaving the bioabsorbable plug in
sealing relation to a puncture wound;
[0043] Fig. 4 is a view like that of Fig. 3, but depicting the plug
in its enlarged configuration;
[0044] Fig. 5 is a view of an alternative embodiment where the
bioabsorbable seal is positioned on an inside surface of a
lung;
[0045] Fig. 6 is a view of an alternative embodiment where the
bioabsorbable seal is positioned on an outside surface of a
lung;
[0046] Fig. 7A is a longitudinal sectional view of a tubular
plug;
[0047] Fig. 7B is a longitudinal sectional view of a plug having an
enlarged leading end;
[0048] Fig. 7C is a longitudinal sectional view of a plug that may
be used as a "scaffold"for therapeutic drugs or the like;F
[0049] Fig. 7D is a longitudinal sectional view of another plug
configuration having utility as a scaffold;
[0050] Fig. 7E is a longitudinal sectional view of another plug
configuration having utility as a scaffold;
[0051] Fig. 7F is a longitudinal sectional view of another plug
configuration having utility as a scaffold;
[0052] Fig. 7G is a longitudinal sectional view of another plug
configuration having utility as a scaffold;
[0053] Fig. 7H is a view of an alternative, hollow bioabsorbable
plug;
[0054] Fig. 8A is a view of a bioabsorbable suture in
isolation;
[0055] Fig. 8B is a view of a bioabsorbable suture in use to close
an incision;
[0056] Fig. 9A is a view depicting the formation of a blind bore or
core in the myocardium of a mammalian heart;
[0057] Fig. 9B is a view depicting the injection of growth factors
into the blind bore;
[0058] Fig. 9C is a view depicting the delivery of a bioabsorbable
seal to the biopsy site;
[0059] Fig. 9D depicts the bioabsorbable seal in sealing relation
to the growth factor;
[0060] Fig. 9E depicts a plurality of blind bores filled with
growth factor and sealed with the bioabsorbable plugs of this
invention;
[0061] Fig. 9F depicts the formation of a cavity in the interior
surface of the myocardium;
[0062] Fig. 9G depicts the plugging of the cavity of Fig. 9F with
the novel bioabsorbable seal so that growth factor is sealed
therein;
[0063] Fig. 10A is a diagrammatic view depicting puncturing of the
thecal sac to withdraw cerebral spinal fluid;
[0064] Fig. 10B is a similar view depicting the delivery of a
dehydrated plug to the puncture site;
[0065] Fig. 10C depicts the hydrated plug in closing relation to
the puncture formed in the thecal sac;
[0066] Fig. 11A is the first view in a series of animations
depicting the first step of a method where an embodiment of the
novel plug is used to seal an incision formed in an artery;
[0067] Fig. 11B is the second view in said series of
animations;
[0068] Fig. 11C is the third view in said series of animations;
[0069] Fig. 11D is the fourth view in said series of
animations;
[0070] Fig. 11E is the fifth and final view in said series of
animations;
[0071] Fig. 12A is a front elevational view of a staple coated with
the novel expandable and bioabsorbable material;
[0072] Fig. 12B is a front elevational view of the staple of Fig.
12A after activation;
[0073] Fig. 12C is a sectional view depicting tissue on opposite
sides of an incision joined to one another by the novel staple;
[0074] Fig. 13A is a diagrammatic view of a cavity formed in tissue
being filled with the novel dehydrated bioabsorbable polymers of
this invention;
[0075] Fig. 13B is a diagrammatic view depicting the cavity filled
by the expanded polymers;
[0076] Fig. 14A is a diagrammatic view of an aneurysm being filled
with the novel dehydrated bioabsorbable polymers of this
invention;
[0077] Fig. 14B is a diagrammatic view depicting the aneurysm
filled by the expanded polymers;F
[0078] Fig. 15A diagrammatically depicts a hole in a septum of a
mammalian heart;
[0079] Fig. 15B is the first diagram in a four series animation
depicting the novel steps for sealing said hole;
[0080] Fig. 15C is the second diagram in said series of
animations;
[0081] Fig. 15D is the third diagram of said series; and
[0082] Fig. 15E is the fourth diagram of said series.
Detailed Description
[0083] Referring to Fig. 1, it will there be seen that the
reference numeral 10 denotes a biopsy site as a whole. Openings in
a mammalian body may be formed by numerous other medical procedures
and non-medical events as mentioned earlier. A biopsy procedure is
explained just for exemplary purposes.
[0084] A biopsy needle 12 is ensleeved within lumen 13 of coaxial
needle 14 when taking biopsy samples from lesion 16 because
multiple entries and withdrawals of biopsy needle 12 are normally
required. In the absence of coaxial needle 14, biopsy needle 12
would have to make multiple punctures of the patient's skin and
lung during a biopsy procedure. Although coaxial needle 14 has a
slightly larger diameter than biopsy needle 12, the trauma caused
by one insertion of said coaxial needle is less than that of
multiple biopsy needle insertions.
[0085] In the example if Fig. 1, the patient's skin is denoted 18
and the surface of the patient's lung is denoted 20. It should be
understood, however, that the utility of this invention is not
restricted to sealing openings formed in lungs by biopsy procedures
but includes the sealing of openings formed by any means in the
heart, brain, liver, kidneys, and even in hard tissue such as bone,
cartilage, and the like.
[0086] When a sufficient amount of biopsy samples have been taken,
biopsy needle 12 is withdrawn from coaxial needle 14.
[0087] As depicted in Fig. 2, a pusher assembly that includes a
circular disc 24 and a rod 26 then slidingly introduces dehydrated
plug 22 into lumen 13 of coaxial needle 14. In this first-described
embodiment, plug 22 is of solid cylindrical construction, is about
2.5 cm in length, and is positioned approximately as shown in Fig.
2, i.e., a small extent of the plug is external to surface 20 of
the lung and a larger extent thereof is inside the lung. This
particular positioning is not critical and is depicted just to
indicate that plug 22 is preferably a relatively long cylindrical
plug, in this particular application, so that it is relatively easy
to position in sealing relation to the puncture opening. The
elongate extent of plug 22 provides a generous margin of error.
[0088] Fig. 3 depicts biopsy site 10 after withdrawal of coaxial
needle 14. Pusher disc 24 and rod 26 (Fig. 2) are held in place
when coaxial tube 14 is withdrawn to ensure that plug 22 does not
move. After coaxial tube 14 is fully withdrawn, pusher disc 24 and
rod 26 are withdrawn to produce the view of Fig. 3.
[0089] Plug 22 is formed of a material that expands upon contact
with a stimulant such as water, blood, air, visible light or other
electromagnetic radiation such as a laser beam, a preselected
chemical, and so on. In a preferred embodiment, the stimulant is
moisture which is naturally present on the surface of a patient's
lungs or other soft tissue, internal organs, or the like.
[0090] Fig. 4 depicts plug 22 shortly after its installation. It
has been in contact with moisture, or other predetermined
stimulant, for a few moments and the expandable material has
expanded. The expansion effectively seals the peripheral edge of
the puncture opening and prevents air from escaping the lungs. In
other applications, the plug is used to stop bleeding or other
liquid fluid flow from the liver, heart, thecal sac, etc.
[0091] An alternative embodiment is depicted in Fig. 5. In this
embodiment, bioabsorbable element 22a is releasably secured to the
distal end of rod 28. Element 22a is disk-shaped, having less
longitudinal extent than bioabsorbable plug 22 of the first
embodiment. Plug 22a has an unexpanded diameter that is preferably
slightly greater than that of plug 22 so that it deploys to a
diameter that is at least slightly greater than the diameter of the
puncture wound when coaxial rod 14, not shown in Fig. 5, is
retracted. Rod 28 is then retracted and separated from plug 22a
when said plug 22a is firmly positioned in sealing relation to the
inner wall of lung 20.
[0092] There are numerous means for interconnecting rod 28 and plug
22a such that said rod may be separated from plug 22a when said
plug is firmly positioned in sealing relation to the puncture
opening. An adhesive having a predetermined strength may be used,
for example, and separation would occur upon applying a torque to
rod 28 about its longitudinal axis.
[0093] Another alternative embodiment is depicted in Fig. 6. This
embodiment is much like the embodiment of Fig. 5 except that plug
22a is positioned in firmly sealing relation to the puncture
opening on the exterior surface of the lung prior to separation of
plug 22a and rod 28.
[0094] Figs. 7A-H depict a few of the possible variations of plug
22. All of these plugs are in a dehydrated condition when
positioned within lumen 13 of coaxial needle 14 and are expanded by
contact with the body's natural moisture or by other means as
mentioned earlier upon being pushed from said lumen by the
earlier-mentioned pusher assembly.
[0095] In Fig. 7A, plug 22 is of tubular construction. This plug
would not have utility in sealing an opening in a lung,
obviously.
[0096] Plug 22 of Fig. 7B has an enlarged anchor member 22b at its
leading end. Anchor member 22b is compressed when plug is within
lumen 13 and expands at least to some extent under its own bias
upon emergence from said coaxial needle.
[0097] Plug 22 of Fig. 7C is generally "U"-shaped when seen in
longitudinal cross-section as in said Fig. 7C.
[0098] Plug 22 of Fig. 7D has a structure similar to that of Fig.
7C but further includes an outwardly turned flange 22c at its
leading end. Flange 22c performs the same function as anchor member
22b of Fig. 7B, i.e. it prevents longitudinal travel of the plug in
a direction toward the surface of the body, it being understood
that the flange or anchor member is positioned in abutting relation
to an interior side of an opening formed in an organ or other
tissue.
[0099] Plug 22 of Fig. 7E has an irregular or corkscrew leading
end. Fig. 7F depicts a plug having a leading end in the
configuration of a tapered corkscrew. Plug 22 of Fig. 7G includes a
medal part of irregular configuration flanked by a leading and a
trailing end of solid cylindrical configuration.
[0100] Significantly, the embodiments of Figs. 7C-G enable plug 22
to serve as a "scaffold" upon which may be deposited growth
hormone, stem cells, therapeutic drugs or any type, and so on. The
increased surface area provides means for holding such therapeutic
elements. Plug 22 or 22a may have a solid or hollow construction.
The embodiment 22b of Fig. 7H is hollow and is filled with a
gaseous fluid either just before or just after it is positioned in
sealing relation to a puncture opening. The gaseous fluid is
introduced into the hollow interior of plug 22b through rod 30,
said rod being in fluid communication with balloon-like neck 22c of
plug 22b. Plug 22b is expanded by gas introduction until it firmly
seals the opening. Neck 22c is then sealed by any suitable
means.
[0101] Alternatively, plug 22b is filled with a gaseous fluid prior
to its use and neck 22c is sealed prior to introduction of the
plug.
[0102] It should be understood that the lung is not the only
internal organ of the body that may be punctured by a needle or
other medical or non-medical device and require sealing. Openings
formed in any vascular organs such as the kidneys, the liver, the
heart, the brain, and the stomach, for example, may be sealed with
the novel apparatus. Nor is the invention limited to the sealing of
vascular organs. For example, it may be used to seal an opening
formed in the thecal sac. The novel apparatus has utility in
sealing openings formed by any means in any mammalian soft or hard
tissue.
[0103] It may also be used to seal surgical sites of the type
created during arthroscopic, endoscopic, or laporoscopic procedures
conducted on the knee, back, and neck, for example. The diameter of
the expandable, bioabsorbable plug would be increased as required
to fill the trocar or other device that performs the role of a
coaxial needle.
[0104] As an additional example, the novel plug may be employed to
seal an incision of a femoral artery.
[0105] Plug 22 is formed of a bioabsorbable material so that it is
bioabsorbed by the body as the opening heals. Since people heal at
different rates, a bioabsorbable material should be selected so
that it is fully bioabsorbed in a period of time such as a few
weeks to a few months.
[0106] Examples of suitable bioabsorbable materials that expand
when contacted by water include hydrogels, collagen, polysalactic
acid, and any other suitable hydrophilic agents.
[0107] Examples of polymers that swell in the presence of aqueous
fluids such as biological fluids will now be disclosed. Virtually
all of the following polymers are hydrogels. Synthetic hydrogels
can be prepared from the following classes of polymers and these
are generally considered to be non-biodegradable:poly(hydroxyalkyl
methylacrylates) such as poly(glyceryl
methacrylate)poly(acrylamide) and poly(methacrylamide) and
derivativespoly(N-vinyl-2-pyrrolidone)anionic and cationic
hydrogelspoly(vinyl alcohol)poly(ethylene glycol) diacrylate and
derivatives from block copolymers composed of poly(ethylene
oxide)-poly(propylene oxide)-poly(ethylene oxide) and
poly(propylene oxide)-poly(ethylene oxide)-poly(propylene oxide)
blocks, respectively; All of the above can be cross-linked with
agents such as ethylene glycol dimethacrylate or
methylene-bis-acrylamide.
[0108] Biodegradable synthetic hydrogels can be prepared from
polymers such as those listed above by incorporating one or more of
the following monomers:Glycolide, Lactide, e-Caprolactone,
p-Dioxanone and Trimethylene CarbonateIn addition, biodegradable
hydrogels can be based on natural products such as the
following:Polypeptides such gelatin which may be cross-linked with
formaldehyde or glutaraldehyde and various other dialdehydes.
[0109] Modified chitin hydrogels, which may be prepared from
partially N-deacetylated chitin which, may then be cross-linked
with agents such as glutaraldehyde.
[0110] Dextran, a polysaccharide, can be derivatized with groups
such as 3-acryloyl-2-hydroxypropyl esters and subsequently
cross-linked by free radical copolymerization with N',N'
-ethylenebisacrylamide.
[0111] Starch may be similarly derivatized or using glycidyl
acrylate followed by free radical cross-linking as described
above.
[0112] The novel plug is also treated so that it is visible under
fluoroscopy, ultrasound, X-ray, magnetic resonance imaging,
computed axial tomography (CAT) scanning, and other imaging
techniques. Accordingly, it may contain or be impregnated with a
contrast solution containing radium, iodine, beryllium, or other
contrasting agent.
[0113] The bioabsorbable material of this invention could also be
fabricated in a thread-like form and used as a suture material.
Alternatively, after a suture has been made using conventional
suture material, the bioabsorbable material could be topically
applied to the sutured area to help seal the punctures made by the
suture.
[0114] Fig. 8A depicts an elongate thread of suture material 32
formed of the novel dehydrated hydrogel material of this invention
and Fig. 8B depicts said suture material 32 in use to close an
incision formed in tissue 33.
[0115] In a first suture embodiment, suture material 32 is formed
entirely of the dehydrated hydrogels of this invention. When suture
material 32 comes into contact with tissue, the natural moisture
within the tissue causes material 32 to expand and seal the hole
created by the needle, it being understood that the needle has a
diameter greater than that of the suture material 32. The body
heals as the bioabsorbable suture is absorbed and no suture
material remains after the holes have completely closed as a result
of natural healing.
[0116] In a second embodiment, regular PGA/PLA sutures or even
non-bioabsorbable sutures are coated with the novel suture
material, i.e., extensible type polymers such as hydrogel that have
been dehydrated. Figs. 8A and 8B should also be interpreted as
depicting this second embodiment. The coating expands upon contact
with the moisture in the tissue. The non-bioabsorbable suture
underlying the bioabsorbable suture material will remain, of
course, after the bioabsorbable material has been absorbed but the
body's natural healing process will have sealed the holes around
the suture. Where a regular PGA/PLA suture is coated, it too will
bioabsorb as the coating is bioabsorbed.
[0117] Advantageously, the body's natural moisture, in most
applications, will cause the suture or the suture coating to expand
to fill the space around it created by the larger diameter of the
needle. This eliminates the need to apply an adhesive over the
sutures and thus eliminates the step of curing the adhesive.
[0118] Figs. 9A 9G disclose how the novel plugs can be used to fill
cavities formed in heart tissue to promote angiogenesis in heart
patients. Growth factor, stem cells, or the like are placed in the
cavities or blind bores and sealed therein by means of the novel
plugs disclosed herein. In Fig. 9A, coaxial needle 40 is depicted
in penetrating relation to epicardium 42 and myocardium 44.
Endocardium 46 is not penetrated to avoid puncturing left ventricle
48 of heart 50 in this particular example. Biopsy needle 52 is
inserted through the lumen of coaxial needle 40 to remove a core of
tissue from myocardium 44. This creates a blind bore in myocardium
44.
[0119] Biopsy needle 52 is then removed from the lumen of coaxial
needle 40 and a delivery sheath 54 is inserted into the lumen of
said coaxial needle as depicted in Fig. 9B. Growth factor 55 such
as vascular endothelial growth factor, stem cells, or the like are
pushed into the blind bore from the lumen of delivery sheath 54 by
plunger 56.
[0120] Plunger 56 is then momentarily withdrawn from the lumen of
delivery sheath 54 and a dehydrated bioabsorbable plug 22d is
inserted into said lumen. Plunger 56 is then retrieved to push plug
22d into sealing relation to the blind bore as indicated in Fig.
9C.
[0121] Fig. 9D depicts plug 22d in said sealing relation. Growth
factor 55 deposited into the bottom of the blind bore is sealed
therein by bioabsorbable plug 22d. Plug 22d is hydrated by the
natural moisture or body fluids of the myocardium and in Fig. 9D
has expanded to tightly seal the blind bore so that growth factor
55 cannot leak therefrom.
[0122] Fig. 9E depicts multiple blind bore sites filled with growth
factor 55 and sealed by plugs 22d. Growth factor 55 promotes
angiogenesis so that newly formed blood vessels can perform the
function of dead or damaged blood vessels throughout the damaged
region of the heart. Exterior surface 23 of each plug 22d is
hydrophillic so that pericardium tissue does not attach to the
biopsied site.
[0123] The blind bores or cavities can also be formed in the
interior surface of the myocardium as depicted in Figs. 9F and 9G.
Cavity 53 in Fig. 9F is formed in endocardium 46 by a biopsy gun or
other suitable instrument and filled with growth factor. Epicardium
42 is not punctured in this embodiment. Dehydrated bioabsorbable
plug 22d is then slid into sealing relation to cavity 53 by a
suitable plunger means to create the structure seen in Fig. 9G.
Damaged heart tissue in the vicinity of cavity 53 is then
regenerated by neovascularization. Multiple cavities 53 can be
formed in the interior side of myocardium 44 as needed.
[0124] Fig. 10A depicts coaxial needle 40 that receives the needle
of syringe 58 used to withdraw spinal fluid 59 from spinal cord 60.
Neck muscle is denoted 61.
[0125] Syringe 58 is then withdrawn and as indicated in Fig. 10B,
dehydrated bioabsorbable plug 22d is pushed from the lumen of
delivery catheter 54 by plunger 56 into sealing relation with the
opening made by the needle of syringe 58.
[0126] Fig. 10C depicts bioabsorbable plug 22d in sealing relation
to the opening made by said needle. Said plug 22d is in its
expanded configuration due to the natural moisture provided by
spinal fluid 59, spinal cord 60, and neck muscles 61.
[0127] Figs. 11A 11E depict how a plug of this invention may be
employed to seal an incision made in an artery.
[0128] In Fig. 11A, guide wire 70 is depicted inserted into femoral
or other artery 72 through incision 71, which may be made for
diagnostic or intervention purposes. After the primary diagnostic
or intervention procedures have been performed, the instruments
used are removed but guide wire 70 is left in position so that it
may be used as follows. Leading end 74a of introducer sheath 74 is
positioned in abutting relation to artery 72 and in surrounding
relation to incision 71. Reference numeral 73 denotes fat and 75 is
the skin surface.
[0129] A dehydrated bioabsorbable material 22e in the form of a
tube is then introduced through lumen 76 of introducer sheath 74 so
that its leading end also abuts artery 72 in surrounding relation
to incision 71, as depicted in Fig. 11B.
[0130] Introducer sheath 74 is then withdrawn, leaving tube 22e in
encircling relation to incision 71 as depicted in Fig. 11C.
[0131] Guide wire 70 is then removed. As indicated in Fig. 11D, an
introducer sheath 80 having a smaller external diameter than
introducer sheath 74 of Fig. 11B, is employed to position
dehydrated plug 22f in plugging relation to tube 22e. Specifically,
plug 22f is disposed in lumen 81of introducer sheath 80 and the
leading end of said introducer sheath 80 is slideably inserted into
the trailing end of tube 22e as depicted. Plunger 82 is then
employed to push plug 22f into tube 22e. Note that plug 22f need
not abut incision 71 to accomplish its sealing function.
[0132] Fig. 11E depicts tube 22e and plug 22f after withdrawal of
introducer sheath 80 and plunger 82. Both tube 22e and plug 22f are
now hydrated by the natural moisture of the body. Accordingly, both
have expanded and are held in place by fat 23 and by each other.
Moreover, the moisture content of the blood flowing through the
artery also serves to cause the expansion of tube 22e and plug 22f.
Incision 71 will heal gradually and tube 22e and plug 22f will be
bioabsorbed over time. The trailing end of tube 22e that projects
upwardly from the surface of skin 75 may be trimmed so that it is
flush with said skin or slightly countersunk with relation
thereto.
[0133] Figs. 12A-C depict the use of the novel material in the
context of staples. Conventional, nonbioabsorbable staples are
often used to close incisions. The staples of this embodiment are
used in end-end and end-side anastomosis of organs such as the
lung, the bowel, and the like. Fig. 12A depicts a staple 90 before
it has been used and Fig. 12B depicts said staple 90 after
activation. Fig. 12C depicts said staple when holding together two
pieces of tissue 91 and 92 separated by incision 93. This
embodiment requires the use of the novel material as a coating over
a conventional staple because the conventional staple provides the
required stiffness to enable the staple to punch through tissue
layers 91, 92. The coating then expands to seal the holes created
by the staple and the holes heal gradually as the bioabsorbable
coating is bioabsorbed.
[0134] From the foregoing, it is apparent that the novel method
includes the steps of sealing an opening of the type made by a
needle or other medical or non-medical instrument by providing a
plug formed of a bioabsorbable material that expands in response to
a predetermined stimulus. The plug may be positioned within the
lumen of a needle, a delivery sheath, or the like, and pushed
therefrom by a suitable pushing means or it may installed by any
other suitable method. The particular method of installation
depends upon the type of opening being plugged and the particular
method of application is not critical to this invention. In an
exemplary embodiment involving a needle, the plug is slidingly
displaced by a plunger means to a preselected location near a
distal end of the lumen of the needle. Withdrawal of the needle
coupled with maintaining the plug at the preselected location
results in placement of the plug at the preselected location. The
predetermined stimulus is then applied to cause expansion of the
plug and sealing of the opening made by the needle.
[0135] Where the novel material is formed into a thread-like form
for use as a suture material, or as a coating for conventional
suture material which or may not be bioabsorbable, the novel method
includes the steps of sewing an opening in accordance with
acceptable medical procedure. In most applications, the natural
moisture of the body will then cause the suture or the coating to
expand radially and to thereby fill the space around it created by
the larger diameter of the needle. Where insufficient moisture is
present, it can simply be brushed or sprayed on in the form of a
saline solution, for example. As mentioned earlier, other
activating agents other than moisture are also within the scope of
this invention.
[0136] Where the novel material is used as a coating for
conventional staples, the novel method includes the step of using
the coated staples in accordance with acceptable medical practice.
The coating expands to fill openings or holes created by the
staples and said coating is bioabsorbed as the opening heals.
[0137] The novel expandable polymers also have utility in filling
cavities in tissue. For example, as depicted in Fig. 13A, a cavity
100 may be formed in tissue 102 such as a liver or other organ when
a tumor or lesion is removed. Catheter 104 is introduced to the
site and a plurality of dehydrated plugs 22 of the novel material
are pushed into cavity 100. As depicted in Fig. 13B, plugs 22
expand upon contact with naturally present moisture and fill the
cavity. This prevents infections or other complications that may
arise if the cavity is left unfilled.
[0138] As another example, novels plugs 22 may also be used to fill
a space created by an aneurysm. In Fig. 14A, aneurysm 106 has
formed a pocket adjacent artery 108. Catheter 110 is introduced
into aneurysm 106 through artery 108 and a plurality of the novel
plugs 22 in dehydrated condition are pushed into the aneurysm. As
indicated in Fig. 14B, available natural moisture causes expansion
of plugs 22 and the cavity left behind by the aneurysm is
filled.
[0139] It is therefore understood that the novel plugs have utility
not just in applications where an opening has been formed in the
surface of tissue, but in filling cavities or other pockets within
tissue as well, without regard to the cause of the cavity or
pocket.
[0140] It should also be understood that there are applications
where waiting for natural body fluids to activate the dehydrated
plug or plugs may be contraindicated. In those applications, saline
or other suitable source of moisture is injected into the lumen of
the needle or catheter of other plug-delivery device before the
plug is pushed therefrom and deposited into an opening or cavity.
In this way, hydration of the plug begins while the plug is still
undeployed so that the time required for full expansion after the
plug has left the delivery device is reduced or even
eliminated.
[0141] Yet another application for the novel expandable,
bioabsorbable materials is in the patching of a hole or holes in a
mammalian heart. In the example of Fig. 15A, a hole 120 in septum
122 unacceptably provides fluid communication between right atrium
124 and left atrium 126. As indicated in Fig. 15B, guide wire 70 is
fed through femoral vein 128 so that the distal free end of guide
wire 70 passes though hole 120 in septum 122 and enters into left
atrium 126. A delivery catheter or sheath 130 is then fed over the
guide wire until the distal free end of the sheath is also
positioned within left atrium 126.
[0142] Guide wire 70 is then removed as indicated in Fig. 15C. Plug
22 is then pushed from the lumen of sheath 130, by holding it in
place with a plunger while slightly withdrawing sheath 130, until
the distal free end of the plug is positioned within the left
atrium. Plug 22 is allowed to expand upon contact with natural
moisture in the heart. It may also be pre-hydrated by injecting
saline or other suitable solution into the lumen of sheath 130
prior to deployment of plug 22 so that the expansion time is
reduced or eliminated. The expansion of plug 22 in left atrium 126
provides an anchoring means so that sheath 130 can be slowly
withdrawn, leaving plug 22 deployed in opening 120.
[0143] Sheath 130 is then withdrawn further as depicted in Fig. 15D
so that plug 22 begins expanding in right atrium 124. Sheath 130 is
then fully withdrawn as depicted in Fig. 15E. Plug 22 is now fully
expanded and hole 120 is closed so that the left and right atriums
are no longer in fluid communication with one another.
[0144] Plug 22 is coated or impregnated with a contrasting agent to
facilitate its viewing and hence accurate placement when employing
various imaging techniques, as in the embodiments described
above.
[0145] A plug used to seal an opening in a heart is preferably
formed of a material that is bioabsorbed very slowly over a long
period of time. Plug 22 may also be impregnated with a growth
factor or other therapeutic agents to promote healing.
[0146] It will thus be seen that the objects set forth above, and
those made apparent from the foregoing description, are efficiently
attained. Since certain changes may be made in the above
construction without departing from the scope of the invention, it
is intended that all matters contained in the foregoing description
or shown in the accompanying drawings shall be interpreted as
illustrative and not in a limiting sense.
[0147] It is also to be understood that the following claims are
intended to cover all of the generic and specific features of the
invention herein described, and all statements of the scope of the
invention that, as a matter of language, might be said to fall
therebetween.
[0148] Now that the invention has been described,
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