U.S. patent application number 11/040996 was filed with the patent office on 2005-07-21 for implantable graft to close a fistula.
This patent application is currently assigned to Cook Incorporated. Invention is credited to Armstrong, David N..
Application Number | 20050159776 11/040996 |
Document ID | / |
Family ID | 34807182 |
Filed Date | 2005-07-21 |
United States Patent
Application |
20050159776 |
Kind Code |
A1 |
Armstrong, David N. |
July 21, 2005 |
Implantable graft to close a fistula
Abstract
An implantable graft, which may be inserted into a fistula tract
to occlude the primary opening of the fistula, is provided. The
graft may have a curved, generally conical shape with a
trumpet-like head end that continuously tapers to a smaller tail
end. The graft may be an integral unit made of a single material,
such as a heterograft material. Methods of closing single and
multiple fistulae are also provided.
Inventors: |
Armstrong, David N.;
(Atlanta, GA) |
Correspondence
Address: |
BRINKS HOFER GILSON & LIONE
P.O. BOX 10395
CHICAGO
IL
60610
US
|
Assignee: |
Cook Incorporated
|
Family ID: |
34807182 |
Appl. No.: |
11/040996 |
Filed: |
January 21, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60538365 |
Jan 21, 2004 |
|
|
|
Current U.S.
Class: |
606/213 ;
128/887 |
Current CPC
Class: |
A61B 17/12131 20130101;
A61B 2017/00641 20130101; A61B 2017/00004 20130101; A61B 2017/00654
20130101; A61B 17/12022 20130101; A61B 17/0057 20130101 |
Class at
Publication: |
606/213 ;
128/887 |
International
Class: |
A61B 017/32; A61D
001/00 |
Claims
1. An implantable graft for closing a fistula, comprising a curved,
generally conical body having a first end with a first diameter and
a second end with a second diameter that is smaller than the first
diameter, where the body comprises a continuous taper between the
first end and the second end.
2. The graft of claim 1 where the body has a length of about 5 to
about 10 centimeters.
3. The graft of claim 2 where the first diameter is about 2 to
about 15 millimeters and the second diameter is about 0.5 to about
3.5 millimeters.
4. The graft of claim 1 where the graft is made of a single
material.
5. The graft of claim 1 where the graft is an integral unit.
6. The graft of claim 1 where the graft comprises a biological
material selected from the group consisting of a cadaveric material
from a human donor and a heterograft material from animal
tissue.
7. The graft of claim 1 where the graft comprises an extracellular
matrix material.
8. The graft of claim 7 where the graft comprises small intestinal
submucosa.
9. The graft of claim 4 where the graft comprises small intestinal
submucosa.
10. The graft of claim 1 where the graft comprises an injectable
heterograft material.
11. The graft of claim 1 further comprising protrusions on an
external surface of the body.
12. The graft of claim 1 where the graft comprises a material
having a portion that remains intact to allow for ingrowth of host
cells.
13. The graft of claim 1 where the graft comprises a material that
promotes angiogenesis.
14. The graft of claim 1 where the graft comprises a material that
promotes site-specific tissue remodeling.
15. The graft of claim 1 where the graft comprises a material that
resists infection.
16. The graft of claim 1 where the graft further comprises a
drug.
17. An implantable plug for closing a fistula, comprising a
generally conical body having a continuous taper between a head end
with a first diameter and a tail end with a smaller second
diameter, where the graft has a length of about 5 to about 10
centimeters.
18. The plug of claim 17 where the plug is made of a single
heterograft material.
19. The plug of claim 18 where the heterograft material is small
intestinal submucosa.
20. The plug of claim 17 where the body is curved.
21. A method for closing a fistula, comprising: a. providing a plug
comprising a generally conical body that continuously tapers from a
head end to a smaller tail end, where the body comprises a single
material; and b. pulling the tail end of the plug into the fistula
through a first end of the fistula until the head end of the plug
contacts the first end of the fistula.
22. The method of claim 21 further comprising securing the first
end of the plug, the second end of the plug, or both ends of the
plug with suture.
23. The method of claim 21 further comprising providing a securing
device having a central lumen, placing the securing device over the
tail end of the plug, and securing the securing device into
position at skin level.
24. The method of claim 21 where the material comprises small
intestinal submucosa.
25. The method of claim 21, where the plug is pulled into the
fistula with a probe or scope.
26. The method of claim 25, where the tail end of the plug is
attached to the probe or scope.
27. The method of claim 25, further comprising introducing an
adhesive into the fistula.
Description
RELATED APPLICATIONS
[0001] The present patent document claims the benefit of the filing
date under 35 U.S.C. .sctn.119(e) of Provisional U.S. Patent
Application Ser. No. 60/538,365, filed Jan. 21, 2004, which is
hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] A graft for occluding a fistula is provided. The graft may
be pulled, tail first, into the fistula to completely occlude the
fistula, thereby avoiding a surgical fistulotomy and its attendant
complications.
BACKGROUND OF THE INVENTION
[0003] Fistulae occur commonly in man. Such fistulae may be
congenital or may be caused by infection, inflammatory bowel
disease (Crohn's disease), irradiation, trauma, childbirth, or
surgery, for example.
[0004] Some fistulae occur between the vagina and the bladder
(vesico-vaginal fistulae) or between the vagina and the urethra
(urethro-vaginal fistulae). These fistulae may be caused by trauma
during childbirth. Traditional surgery for these types of fistulae
is complex and not very successful.
[0005] Other fistulae include, but are not limited to,
tracheo-esophageal fistulae, gastro-cutaneous fistulae, and
anorectal fistulae. For example, anorectal fistulae may occur
between the anorectum and vagina (recto-vaginal fistulae), between
the anorectum and bladder (recto-vesical fistulae), between the
anorectum and urethra (recto-urethral fistulae), or between the
anorectum and prostate (recto-prostatic fistulae). Anorectal
fistulae may result from infection in the anal glands, which are
located around the circumference of the distal anal canal forming
an anatomic landmark known as the dentate line 1, shown in FIGS. 1
and 2. Approximately 20-39 such glands are found in man. Infection
in an anal gland may result in an abscess, which then tracks
through or around the sphincter muscles into the perianal region,
where it drains either spontaneously or surgically. The resulting
tract is known as a fistula. The inner opening of the fistula,
usually located at the dentate line, is known as the primary
opening 2. The outer (external) opening, located in the perianal
skin, is known as the secondary opening 3.
[0006] FIGS. 1 and 2 show examples of the various paths that an
anorectal fistula may take. These paths vary in complexity.
Fistulae that take a straight line path from the primary opening 2
to the secondary opening 3 are known as simple fistulae 4. Fistula
that contain multiple tracts ramifying from the primary opening 2
and have multiple secondary openings 3 are known as complex
fistulae 5.
[0007] The anatomic path that an anorectal fistula takes is
classified according to its relationship to the anal sphincter
muscles 6, 7. The anal sphincter includes two concentric bands of
muscle--the inner, or internal, sphincter 6 and the outer, or
external, anal sphincter 7. Fistulae which pass between the two
concentric anal sphincters are known as inter-sphincteric fistulae
8. Those which pass through both internal 6 and external 7
sphincters are known as trans-sphincteric fistulae 9, and those
which pass above both sphincters are called supra-sphincteric
fistulae 10. Fistulae resulting from Crohn's disease usually ignore
these anatomic paths, and are known as extra-anatomic fistulae.
[0008] Many complex fistulae contain multiple tracts, some
blind-ending 11 and others leading to multiple secondary openings
3. One of the most common and complex types of fistulae are known
as horseshoe fistulae 12, as illustrated in FIG. 2. In this
instance, the infection starts in the anal gland (the primary
opening 2) and two fistulae pass circumferentially around the anal
canal, forming a characteristic horseshoe configuration 12.
[0009] Surgical treatment of fistulae traditionally involves
passing a fistula probe through the tract, in a blind manner, using
only tactile sensation and experience to guide the probe. Having
passed the probe through the fistula tract, the overlying tissue is
surgically divided. This is known as a surgical fistulotomy.
Because a variable amount of sphincter muscle is divided during the
procedure, fistulotomy may result in impaired sphincter control or
even incontinence.
[0010] Alternatively, the fistula tract may be surgically drained
by inserting a narrow diameter rubber drain, known as a seton,
through the tract. After the seton is passed through the fistula
tract, it may be tied as a loop around the contained tissue and
left for several weeks or months. This procedure is usually
performed to drain infection from the area and to mature the
fistula tract prior to a definitive closure or sealing
procedure.
[0011] More recently, methods have evolved to inject sclerosant or
sealant (collagen or fibrin glue) into the tract of the fistula.
Such sealants are described in Rhee, U.S. Pat. No. 5,752,974, for
example. The main drawback with these methods is that the glues
have a liquid consistency and tend to run out of the fistula tract
once the patient becomes ambulatory. In addition, failure rates of
these methods are high (up to 86% failure). See Buchanan et al.,
Efficacy of Fibrin Sealant in the Management of Complex Anal
Fistula, DIS COLON AND RECTUM Vol. 46, No. 9, 46: 1167-1174
(September 2003). Usually, multiple injections of glue are required
to close the fistula. In some instances, closure of a fistula using
a sealant may be performed as a two-stage procedure, comprising a
first-stage seton placement, followed by injection of the fibrin
glue several weeks later. This procedure reduces residual infection
and allows the fistula tract to "mature" prior to injecting a
sealant. Injecting sealant or sclerosant into an unprepared or
infected fistula as a one-stage procedure may cause a flare-up of
the infection and even further abscess formation. Alternative
methods and instruments, such as coring-out instruments (See, e.g.,
U.S. Pat. Nos. 5,628,762 and 5,643,305), simply make the fistula
wider and more difficult to close.
[0012] An additional means of closing the primary opening is by
surgically creating a flap of skin, which is drawn across the
opening and sutured in place. This procedure (the endo-anal flap
procedure) closes the primary opening, but is technically difficult
to perform, is painful for the patient, and is associated with a
high fistula recurrence rate.
[0013] An important step in successful closure of a fistula is
accurate identification and closure of the primary opening. An
accurate means of identifying the primary opening involves
endoscopic visualization of the fistula tract (fistuloscopy), as
disclosed in co-pending application Ser. No. 10/945,634
(Armstrong). Once the primary opening has been accurately
identified, effective closure is necessary to prevent recurrence.
The current invention comprises a graft that may be used to
effectively plug or occlude the primary opening of the fistula
tract.
SUMMARY OF THE INVENTION
[0014] One object of the present invention is to provide a new
technique of minimally invasive fistula closure. Another object is
to provide a technique that obviates the need for surgical
fistulotomy and avoids surgical pain and the attendant
complications of the procedure. Still another object of the
invention is to provide an accurate and complete closure of a
fistula, thereby preventing a recurrent or persistent fistula. Yet
another object of the present invention is to provide a technique
that involves no cutting of tissue, sphincter damage, or
incontinence.
[0015] The present invention may be used in any type of fistula.
For example, the claimed devices and methods may be used to plug or
occlude tracheo-esophageal fistulae, gastro-cutaneous fistulae,
anorectal fistulae, fistulae occurring between the vagina and the
urethra or bladder, or fistulae occurring between any other two
portions of the body.
[0016] In one embodiment of the present invention, a biocompatible
graft having a curved, generally conical shape is provided. The
graft may be used to plug, or occlude the primary opening of the
fistula. Desirably, the graft is approximately 5 to 10 centimeters
(2 to 4 inches) long and tapers continuously from a thicker,
"trumpet-like" head to a thin filamentous tail. Desirably, the
diameter of the head is approximately 5 to 10 millimeters and
tapers to a diameter of 1 to 2 millimeters at its tail.
[0017] The graft of the present invention may be made of any
suitable biological or synthetic materials. Desirably, the head and
the tail are one continuous piece made of the same material.
Suitable biological materials include, but are not limited to,
cadaveric allografts from human donors or heterografts from animal
tissues. Suitable synthetic materials include, but are not limited
to, polygalactin, polydioxanone and polyglycolic acid. Desirably,
the biological and/or synthetic material used in the graft of the
present invention elicits little immunological reaction, has some
inherent resistance to infection, and promotes tissue
reconstruction (rather than complete absorption of the graft into
the surrounding tissue), thereby occluding the fistula.
[0018] The graft of the present invention may be pulled into the
fistula, tail first, through the primary opening, toward the
secondary opening. In one embodiment, the graft is drawn into the
fistula and the trumpet-like head end of the graft is gradually
"wedged" into the primary opening in a manner similar to that of
inserting a plug in a hole. The head and/or tail may be further
secured by sutures or other suitable means, which may be formed as
an integral part of the graft. A trumpet-like head allows the graft
to be used for any diameter of primary opening. By applying
adequate force to the graft during its insertion, the head of the
graft fits snugly into the primary opening and conforms to the size
of the primary opening. Multiple or composite grafts may be used
for multiple or complex fistulae.
[0019] Additional features and advantages of the present invention
will be apparent to one of ordinary skill in the art from the
drawings and detailed description of the preferred embodiments
below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 shows several possible anatomic courses taken by
various forms of anorectal fistula (longitudinal plane);
[0021] FIG. 2 shows a perineal view of a simple anorectal fistula
and a horseshoe fistula; and
[0022] FIG. 3 shows one embodiment of the graft of the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0023] The graft of the present invention may be used to plug or
occlude any type of fistula, such as the types of fistula
illustrated in FIGS. 1 and 2. Other types of fistula that may be
occluded by the present invention include, but are not limited to,
tracheo-esophageal fistulae, gastro-cutaneous fistulae, or fistulae
occuring between the vagina and bladder (vesico-vaginal fistulae),
between the vagina and urethra (urethro-vaginal fistulae), between
the anorectum and vagina (recto-vaginal fistulae), between the
anorectum and bladder (recto-vesical fistulae), between the
anorectum and urethra (recto-urethral fistulae), between the
anorectum and prostate (recto-prostatic fistulae) or between any
other two portions of the body.
[0024] The graft 13 of the present invention may have any suitable
configuration. For example, the graft may have a convex
configuration, a concave configuration, an S-shaped configuration,
a generally straight configuration, or any other configuration
capable of being inserted into and secured within a fistula. The
graft may be curved to conform to the shape of the fistula, thereby
facilitating introduction of the graft, a secure fit of the graft
within the fistula, and less discomfort for the patient. A curved
configuration makes it easier for the graft to be introduced into
the primary opening and directed toward the secondary opening of a
curved fistula. Desirably, the graft 13 is an integral unit with a
curved, generally conical configuration that tapers from one end
having a first diameter D1 to an opposite end having a second
diameter D2, where the first diameter D1 is greater than the second
diameter D2, as shown in FIG. 3.
[0025] The graft 13 may have one end with a thicker trumpet-like
head 14 and a body 16 that continuously tapers to a thin
filamentous tail 15, as shown in FIG. 3. The degree of taper may
vary depending on a number of factors, including but not limited
to, the diameter of each of the ends (D1 and D2) and the length L
of the graft 13.
[0026] Although the graft may have any suitable length L, diameter
D1, and diameter D2, desirably, the graft 13 has a length L of
about 1 to about 15 centimeters, a first diameter D1 of about 1 to
about 20 millimeters, and a second diameter D2 of about 0.1 to
about 5 millimeters. More desirably, the graft 13 has a length L of
about 3 to about 12 centimeters, a first diameter D1 of about 2 to
about 15 millimeters, and a second diameter D2 of about 0.5 to
about 3.5 millimeters. Even more desirably, the graft has a length
L of about 5 to about 10 centimeters, a first diameter D1 of about
5 to about 10 millimeters, and a second diameter D2 of about 1 to
about 2 millimeters. The graft of the present invention may be used
to close any diameter of primary opening up to the limits of the
head diameter D1. By applying adequate force to the graft during
insertion, the head 14 of the graft 13 conforms exactly to the size
of the primary opening.
[0027] The graft 13 of the present invention may be made of any
biocompatible material suitable for implantation into a mammalian
body. Desirably, the graft 13 is made of a single, non-allergenic
biological or synthetic material.
[0028] Suitable biological materials that may be used in the
present invention include, but are not limited to, tissue from the
patient themselves (an autograft), tissue from a human cadaveric
donor (an allograft), or tissue from an unrelated animal donor (a
heterograft). Desirably, the material promotes angiogenesis and/or
site-specific tissue remodeling.
[0029] Autograft tissue is grown from a skin biopsy of the patient.
Once the fibroblasts have regenerated and formed enough new tissue,
the new tissue may be injected back into the surgical site of the
same patient. This process takes several weeks to complete, but
avoids tissue rejection and disease transmission. One such product
is Isolagen (Isolagen Inc.--Houston, Tex.).
[0030] Suitable cadaveric materials include, but are not limited
to, cadaveric fascia and cadaveric dura matar. Specific suitable
cadaveric allografts include, but are not limited to, AlloDerm,
(LifeCell Corp.--Branchburg, N.J.), Cymetra, (LifeCell
Corp.--Branchburg, N.J.), Dermaloga, Fascion (Fascia Biosystems,
LLC--Beverly Hills, Calif.), and Suspend (Mentor--Irving, Tex.).
These products are freeze-dried, or lyophilized, acellular dermal
tissue from cadaveric donors. Some require reconstitution before
implantation. Although disease transmission or antigenic reaction
is possible, the risk may be minimized by an extensive screening
and processing of the material.
[0031] Heterograft materials are taken from a donor of one species
and grafted into a recipient of another species. Examples of such
materials include, but are not limited to, Surgisis (Cook
Surgical--Bloomington, Ind.), Permacol (TSL--Covington, Ga.),
Pelvicol (Bard Inc.--Murray Hill, N.J.) and Peri-Guard,
(Bio-Vascular Inc.--St Paul, Minn.). In one embodiment of the
present invention, an injectable heterograft, such as a heterograft
of small intestinal submucosa or other material having a viscosity
sufficient to prevent the material from running out or being
squeezed out of the fistula, is used.
[0032] Such biological materials may be rendered non-cellular
during processing to avoid immunological rejection. Suitable
biological tissues may be implanted in potentially infected
surgical fields and resist infection, unlike some synthetic
preparations that may elicit a foreign body reaction or act as a
nidus for infection.
[0033] Desirably, a bioremodelable material is used in the devices
and methods of the present invention. More desirably, a
bioremodelable collagenous material is used. Bioremodelable
collagenous materials can be provided, for example, by collagenous
materials isolated from a suitable tissue source from a
warm-blooded vertebrate, and especially a mammal. Such isolated
collagenous material can be processed so as to have bioremodelable
properties and promote cellular invasion and ingrowth and eventual
reconstruction of the host tissue itself. Bioremodelable materials
may be used in this context to promote cellular growth within the
site in which a medical device of the invention is implanted.
[0034] Suitable bioremodelable materials can be provided by
collagenous extracellular matrix materials (ECMs) possessing
biotropic properties. Illustrative suitable extracellular matrix
materials for use in the invention include, for instance, submucosa
(including for example small intestinal submucosa, stomach
submucosa, urinary bladder submucosa, or uterine submucosa, each of
these isolated from juvenile or adult animals), renal capsule
membrane, dermal collagen, amnion, dura mater, pericardium, serosa,
peritoneum or basement membrane materials, including liver basement
membrane or epithelial basement membrane materials. These materials
may be isolated and used as intact natural forms (e.g. as sheets),
or reconstituted collagen layers including collagen derived from
these materials and/or other collagenous materials may be used. For
additional information as to submucosa materials useful in the
present invention, and their isolation and treatment, reference can
be made to U.S. Pat. Nos. 4,902,508, 5,554,389, 5,733,337,
5,993,844, 6,206,931, 6,099,567, and 6,331,319. Renal capsule
membrane can also be obtained from warm-blooded vertebrates, as
described more particularly in International Patent Application
serial No. PCT/US02/20499 filed Jun. 28, 2002, published Jan. 9,
2003 as WO03002165.
[0035] As prepared and used, the ECM and any other collagenous
material used, may optionally retain growth factors or other
bioactive components native to the source tissue. For example,
submucosa or other ECMs may include one or more growth factors such
as basic fibroblast growth factor (FGF-2), transforming growth
factor beta (TGF-beta), epidermal growth factor (EGF), and/or
platelet derived growth factor (PDGF). As well, submucosa or other
ECM when used in the invention may include other biological
materials such as heparin, heparin sulfate, hyaluronic acid,
fibronectin and the like. Thus, generally speaking, the submucosa
or other ECM material may include a bioactive component that
induces, directly or indirectly, a cellular response such as a
change in cell morphology, proliferation, growth, protein or gene
expression.
[0036] Further, in addition or as an alternative to the inclusion
of such native bioactive components, non-native bioactive
components such as those synthetically produced by recombinant
technology or other methods, may be incorporated into the material
used for the covering. These non-native bioactive components may be
naturally-derived or recombinantly produced proteins that
correspond to those natively occurring in an ECM tissue, but
perhaps of a different species (e.g. human proteins applied to
collagenous ECMs from other animals, such as pigs). The non-native
bioactive components may also be drug substances. For example, one
drug substance that may be incorporated into and/or onto the
covering materials is an antibiotic.
[0037] Submucosa or other ECM tissue used in the invention is
preferably highly purified, for example, as described in U.S. Pat.
No. 6,206,931 to Cook et al. Thus, preferred ECM material will
exhibit an endotoxin level of less than about 12 endotoxin units
(EU) per gram, more preferably less than about 5 EU per gram, and
most preferably less than about 1 EU per gram. As additional
preferences, the submucosa or other ECM material may have a
bioburden of less than about 1 colony forming units (CFU) per gram,
more preferably less than about 0.5 CFU per gram. Fungus levels are
desirably similarly low, for example less than about 1 CFU per
gram, more preferably less than about 0.5 CFU per gram. Nucleic
acid levels are preferably less than about 5 .mu.g/mg, more
preferably less than about 2 .mu.g/mg, and virus levels are
preferably less than about 50 plaque forming units (PFU) per gram,
more preferably less than about 5 PFU per gram. These and
additional properties of submucosa or other ECM tissue taught in
U.S. Pat. No. 6,206,931 may be characteristic of any ECM tissue
used in the present invention.
[0038] Suitable synthetic materials that may be used in the present
invention include, but are not limited to, polygalactin,
polydioxanone, hyaluronic acid, polyglycolic acid, and polyethylene
terephthalate. These materials avoid foreign body rejection and may
be eventually incorporated into the host tissue.
[0039] Desirably, the biological or synthetic material used in the
present invention assists in reconstruction of the host tissues,
elicits little immunological reaction, and has some inherent
resistance to infection. Such material allows incorporation of the
graft into the fistula (rather than complete absorption of the
graft into the surrounding tissue), thereby occluding the
fistula.
[0040] In one embodiment of the present invention, a drug, such as
an antibiotic, is incorporated into the graft of the present
invention, as an extra precaution or means of treating any residual
infection within the fistula. The graft may also be used in
conjunction with a sealant or sclerosing solution which may be
injected into the main fistula tract and any side branches. Several
possible sealants are described in the prior art. One of the more
commonly used sealants is fibrin glue, known as Tisseal (Baxter
Inc.). The glue is prepared by mixing coagulation activation
factors with fibrinogen, which react to form fibrin. The fibrin
forms a matrix, which acts as a scaffold for tissue ingrowth and
results in the sealing of the fistula tract.
[0041] The graft 13 of the present invention may be inserted into
the fistula by pulling the tail 15 of the graft 13 through the
primary opening 2 of the fistula and towards the secondary opening
3. This may be accomplished by using, for example, a pair of
surgical hemostats or a fistula probe or scope, which is passed
through the secondary opening 3 and out through the primary opening
2. The tail 15 of the graft 13 may then be grasped by the
hemostats, or secured to the probe or scope, and withdrawn
retrograde into the fistula. As the graft 13 is being withdrawn
through the fistula, the head 14 of the graft 13 may be gradually
"wedged" into the primary opening 2 causing the graft 13 to become
lodged in place so that it does not fall out or exude, as with the
fibrin glue technique.
[0042] To assist in anchoring the graft within the fistula, the
outer surface of the graft may contain protrusions 18 that interact
with the fistula. Anorectal fistulae pass through the cylindrical,
well-defined internal sphincter muscle 6 containing an almost rigid
hole, which is the narrowest point along the fistula tract.
Desirably, the protrusions on the graft are adapted to be pulled
through the hole and wedged against the distal portion of the hole
to further anchor the graft.
[0043] In an alternative embodiment of the present invention,
either end of the graft or both ends of the graft are secured by
sutures and trimmed to avoid either end from protruding excessively
from the fistula tract after the procedure. The suture may be
formed as an integral part of the graft or as a separate
component.
[0044] In another embodiment, the graft is anchored within the
fistula by threading a securing device having a central lumen, over
the tail of the graft and securing it into position at skin level
(e.g., by crimping it). In yet another embodiment, further
anchoring of the graft is achieved by using a material such as a
small intestinal submucosa heterograft (a freeze-dried material
that requires rehydration before use) for the graft and inserting
the graft into the tract before the graft material has been fully
expanded by hydration. Any other suitable means of securement, such
as introducing adhesive into the fistula tract, may also be used to
anchor the graft within the fistula.
[0045] In one embodiment, antologous fibrin glue is used in
conjunction with the fistula graft to supplement the adhesive and
occlusive properties of the disclosed invention. This involves the
use of an autologous composite of platelets and growth factors
derived from the patient's own blood. (Symphony PCS, DePuy AcroMed
Inc.). The composite may be derived from a fresh sample of blood
drawn from the patient at the time of surgery. The blood may then
be centrifuged, and the platelets, which contain growth factors
such as epidermal growth factor (EGF) and transforming growth
factor-beta (TGF.beta.), harvested. Having centrifuged the blood,
retrieved the platelet "pellet" and prepared the composite, the
sealant may then be injected into the fistula tract(s) to help
maintain the graft in place.
[0046] Closure of a fistula tract may be performed as a one-stage
or two-stage procedure. As a one-stage procedure, the fistula tract
is closed or sealed at the same time as the initial surgery. The
advantage of this method is that it avoids a second operation and
minimizes expense and inconvenience. The main disadvantage is that
immediate implantation of the graft into an "unprepared" and
possibly infected fistula tract may result in secondary infection
of the graft. As a two-stage procedure, a seton is first placed
through the fistula tract to allow mechanical drainage of the
fistula tract. Several weeks later, the seton is removed and the
graft is inserted into the fistula.
[0047] An alternative methodology involves preliminary endoscopic
visualization (fistuloscopy) and "cleaning" of the fistula tract,
as disclosed in co-pending application Ser. No. 10/945,634
(Armstrong). This procedure may be performed by a very thin
flexible endoscope, which is inserted into the secondary opening of
the fistula tract, and advanced under direct vision through the
fistula tract and out the primary opening. By performing
preliminary fistuloscopy of the fistula tracts, the primary opening
is accurately identified and the tracts are "cleaned out" by means
of an irrigating fluid. Any inflammatory or necrotic tissue within
the tract is therefore removed, prior to inserting the graft. The
tail of the graft may be attached to the fistuloscope, which may
then be withdrawn through the fistula tract so that the graft gets
wedged in place, as described above.
[0048] For multiple fistula, multiple grafts may be inserted until
all fistula tracts have been closed. In the case of a complex
fistula, for instance the horseshoe fistula, there may be one
primary opening and two or more tracts leading from that opening.
In this instance, a graft may be configured with one "head"
component (larger diameter end), and two "tails" (smaller diameter
ends). Desirably, accurate identification of all fistula tracts and
the primary opening is facilitated by first performing
fistuloscopy. Once the entire tract has been identified and cleaned
out, each tail may be pulled through the primary opening into each
fistula in turn, desirably using a fistuloscope or an instrument
passed through the instrument channel of a scope. Adequate force
may be applied to the tail to ensure that the head of the graft is
firmly secured in the primary opening. The head of the graft and/or
each of the tails may be further secured by any of the methods
described above.
[0049] The success of the present invention was demonstrated in a
clinical trial evaluating the efficacy of a biodegradable
lyophilized porcine submucosa plug, as compared to the fibrin glue
technique, in closing anorectal fistulae. Thirteen of fifteen
patents (87%) treated with the plug had complete closure of all
fistula tracts, whereas only four of ten (40%) patents treated with
the fibrin glue technique had complete closure.
[0050] It is intended that the foregoing detailed description be
regarded as illustrative rather than limiting, and that it be
understood that it is the following claims, including all
equivalents, that are intended to define the spirit and scope of
this invention.
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