U.S. patent application number 16/856637 was filed with the patent office on 2020-10-08 for implantable biocompatible expander suitable for treatment of constrictions of body lumen.
The applicant listed for this patent is The Provost, Fellows, Foundation Scholars, & The Other Members of Board, of the College of the Holy. Invention is credited to Michael Burke, Conor Harkin, Bruce Murphy, Riona Ni Ghriallais, James Redmond, Garrett Ryan.
Application Number | 20200315823 16/856637 |
Document ID | / |
Family ID | 1000004914932 |
Filed Date | 2020-10-08 |
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United States Patent
Application |
20200315823 |
Kind Code |
A1 |
Harkin; Conor ; et
al. |
October 8, 2020 |
IMPLANTABLE BIOCOMPATIBLE EXPANDER SUITABLE FOR TREATMENT OF
CONSTRICTIONS OF BODY LUMEN
Abstract
An implantable biocompatible expander suitable for implantation
into a urinary duct, comprises an elongated sinusoidal ring
comprising at least two proximal prongs and at least two distal
prongs, wherein the expander is resiliently deformable from a
relaxed radially expanded orientation to a radially contracted
orientation suitable for transluminal delivery through the urinary
duct. The expander is configured to exert an outward radial force
against a wall of the urinary duct when in-situ within the urinary
duct. In particular, the expander is suitable for treatment of
benign prostatic hyperplasia and configured for implantation into
the prostatic urethra between, and substantially spanning the
prostatic urethra between, the bladder neck and external
sphincter.
Inventors: |
Harkin; Conor; (Dublin,
IE) ; Ryan; Garrett; (Dublin, IE) ; Murphy;
Bruce; (Dublin, IE) ; Redmond; James; (Dublin,
IE) ; Burke; Michael; (Dublin, IE) ; Ni
Ghriallais; Riona; (Dublin, IE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The Provost, Fellows, Foundation Scholars, & The Other Members
of Board, of the College of the Holy |
Dublin |
|
IE |
|
|
Family ID: |
1000004914932 |
Appl. No.: |
16/856637 |
Filed: |
April 23, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15351282 |
Nov 14, 2016 |
10682245 |
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16856637 |
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62321639 |
Apr 12, 2016 |
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62254480 |
Nov 12, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M 29/02 20130101;
A61F 2250/0067 20130101; A61B 1/307 20130101; A61F 2002/047
20130101; A61F 2230/0095 20130101; A61F 2002/825 20130101; A61F
2/86 20130101; A61F 2230/0054 20130101; A61F 2230/0023 20130101;
A61F 2/848 20130101; A61F 2002/8483 20130101; A61F 2210/0004
20130101; A61F 2230/0013 20130101; A61F 2230/0056 20130101; A61F
2230/0069 20130101; A61F 2002/9665 20130101; A61F 2/966 20130101;
A61F 2250/0039 20130101; A61F 2230/0067 20130101; A61F 2/04
20130101 |
International
Class: |
A61F 2/86 20060101
A61F002/86; A61F 2/04 20060101 A61F002/04; A61F 2/966 20060101
A61F002/966; A61B 1/307 20060101 A61B001/307; A61F 2/848 20060101
A61F002/848; A61M 29/02 20060101 A61M029/02 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 12, 2015 |
EP |
15194391.7 |
Claims
1. A method of treating benign prostatic hyperplasia in a patient,
the method comprising: by transluminal delivery through the
patient's urethra, positioning an expandable implant, in a
contracted configuration, at a target location within the patient's
prostatic urethra, the implant having at least three proximal
prongs; and at the target location, resiliently self-expanding the
implant from the contracted configuration to effect dilation of the
prostatic urethra while causing the at least three proximal prongs
of the implant to sit within respective ones of the most lateral
triangular recesses of the prostatic urethra.
2. The method as claimed in claim 1, wherein each proximal prong is
connected to longitudinal struts and said dilation of the prostatic
urethra is effected by pressing those longitudinal struts against a
wall of the prostatic urethra.
3. The method as claimed in claim 2, comprising flexing one or more
of the longitudinal struts to follow a wall shape of the prostatic
urethra.
4. The method as claimed in claim 3, comprising flexing one or more
of the longitudinal struts to follow changes in the wall shape of
the prostatic urethra.
5. The method as claimed in claim 2, comprising spanning at least
50% of the length of the prostatic urethra by the longitudinal
struts.
6. The method as claimed in claim 1, wherein positioning the
implant comprises locating the patient's verumontanum within an
open area defined between adjacent longitudinal struts of the
implant.
7. The method as claimed in claim 6, wherein positioning the
implant comprises positioning a distal prong of the implant
distally with respect to the patient's verumontanum, that distal
prong connecting said adjacent longitudinal struts.
8. The method as claimed in claim 7, wherein said distal prong
positioned distally with respect to the verumontanum also pushes
against a median lobe of the prostatic urethra.
9. The method as claimed in claim 1, wherein positioning the
implant comprises positioning distal prongs of the implant such
that when the implant is self-expanded, at least one of the distal
prongs pushes against the transition zone of the patient's prostate
gland to expand the lumen of the prostatic urethra at that
location.
10. The method as claimed in claim 9, wherein others of the distal
prongs push against lateral lobes of the prostatic urethra.
11. The method as claimed in claim 1, wherein the implant has a
triangular cross-sectional shape and the method comprises orienting
the implant to match that cross-sectional shape with a triangular
cross-sectional shape of the prostatic urethra.
12. The method as claimed in claim 11, wherein matching the
cross-sectional shape of the implant with the cross-sectional shape
of the prostatic urethra comprises aligning the at least three
proximal prongs with the most lateral triangular recesses of the
prostatic urethra.
13. The method as claimed in claim 11, wherein matching the
cross-sectional shape of the implant with the cross-sectional shape
of the prostatic urethra comprises aligning at least three distal
prongs of the implant with respective lobes of the prostatic
urethra.
14. The method as claimed in claim 1, wherein self-expanding the
implant presses at least three distal prongs of the implant against
walls of the prostatic urethra.
15. The method as claimed in claim 1, wherein self-expanding the
implant exerts an outward radial force against walls of the
prostatic urethra.
16. The method as claimed in claim 15, comprising exerting a
greater outward radial force against the walls of the prostatic
urethra at a proximal end and at a distal end of the implant than
between those ends of the implant.
17. The method as claimed in claim 1, wherein self-expanding the
implant invaginates the implant into a wall of the prostatic
urethra.
18. The method as claimed in claim 1, comprising expanding the
implant without a balloon.
19. The method as claimed in claim 1, wherein positioning the
implant at the target location comprises positioning a distal end
of the implant at least 5 mm proximally from a neck of the
patient's bladder.
20. The method as claimed in claim 1, wherein positioning the
implant at the target location comprises positioning a proximal end
of the implant at least 5 mm distally from the patient's external
urethral sphincter.
21. The method as claimed in claim 1, comprising differentially
flexing distal and proximal ends of the implant when at the target
location.
22. The method as claimed in claim 21, wherein differentially
flexing the distal and proximal ends of the implant causes
respective cross-sectional areas of the proximal and distal ends to
vary relative to each other.
23. The method as claimed in claim 1, wherein a radially-outwardly
facing surface of the implant constitutes less than 10% of a total
open area of the implant when the implant is self-expanded at the
target location.
24. A method of treating benign prostatic hyperplasia in a patient,
the method comprising: by transluminal delivery through the
patient's urethra, positioning an expandable implant, in a
contracted configuration, at a target location within the patient's
prostatic urethra by positioning a distal prong of the implant
distally with respect to the patient's verumontanum; and at the
target location, resiliently self-expanding the implant from the
contracted configuration to effect dilation of the prostatic
urethra, accommodating the verumontanum within an open area defined
between adjacent longitudinal struts of the implant that extend
proximally from the distal prong.
25. A method of treating benign prostatic hyperplasia in a patient,
the method comprising: by transluminal delivery through the
patient's urethra, positioning an expandable implant, in a
contracted configuration, at a target location within the patient's
prostatic urethra, the implant being a sinusoidal ring having at
least three proximal prongs, at least three distal prongs and
longitudinal struts that connect the proximal prongs to the distal
prongs; and at the target location, resiliently self-expanding the
implant from the contracted configuration to effect dilation of the
prostatic urethra by pressing the longitudinal struts against a
wall of the prostatic urethra, each of the longitudinal struts
spanning the wall of the prostatic urethra with inclination between
the proximal prongs and the distal prongs.
26. A method of positioning an expandable implant at a target
location within a patient's prostatic urethra for treating benign
prostatic hyperplasia in the patient, the method comprising: by
transluminal delivery through the patient's urethra, positioning
the expandable implant, in a contracted configuration, at the
target location within the patient's prostatic urethra; and, at the
target location, imaging the implant when positioning the implant;
orienting the implant, in dependence on said imaging, such that
proximal prongs of the implant are aligned with respective most
lateral triangular recesses of the prostatic urethra; and
resiliently self-expanding the implant from the contracted
configuration to effect dilation of the prostatic urethra while
causing the proximal prongs of the implant to sit within said
respective recesses of the prostatic urethra.
27. The method as claimed in claim 26, wherein imaging the implant
is performed from within a hollow delivery device that delivers the
implant to the target location.
28. The method as claimed in claim 27, comprising illuminating a
part of the prostatic urethra adjacent to a distal end of the
delivery device.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 15/351,282, filed on Nov. 14, 2016, which claims the benefit of
U.S. Provisional Application No. 62/321,639, filed on Apr. 12,
2016. U.S. application Ser. No. 15/351,282 claims priority under 35
U.S.C. .sctn. 119 or 365 to European Application No. EP 15194391.7,
filed on Nov. 12, 2015. U.S. application Ser. No. 15/351,282 claims
the benefit of U.S. Provisional Application No. 62/254,480, filed
on Nov. 12, 2015. The entire teachings of the above applications
are incorporated herein by reference.
BACKGROUND
[0002] Benign prostatic hyperplasia (BPH) involves hyperplasia of
prostatic stromal and epithelial cells, resulting in formation of
large discrete nodules in the transition zone of the prostate
gland. When sufficiently large, the nodules impinge on the
prostatic urethra and increase resistance to flow of urine from the
bladder, causing discomfort for the patient. Resistance to urine
flow requires the bladder to work harder during voiding, leading to
progressive hypertrophy, instability and weakness of the bladder
muscle. Various treatments are available for BPH, including
medication such as alpha blockers and 5-reductase inhibitors, clean
intermittent self-catheterisation, surgery and minimally invasive
therapies such as transurethral microwave thermotherapy and
transurethral needle ablation. A further treatment option is to
implant a stent within the prostatic urethra. One such stent is
described in U.S. Pat. No. 5,269,802 and comprises two rings
connected by three struts that maintain the two rings in a
co-planar relationship. In use, the larger of the two rings is
placed in the bladder and the smaller ring is placed in the
prostatic urethra. Prostatic stents can offer immediate relief for
symptoms of BPH but they have fallen out of favour due a high rate
of side effects. They are usually long cylindrical type stents that
resemble traditional stents used in in the heart blood vessels or
for peripheral vascular disease. They can migrate from their
deployment position and travel to the bladder or to the membranous
urethra (up to 12.5% of patients), encrust and block urethra (up to
27.5%), cause incontinence (up to 3%) and pain. Cases of a profound
inflammatory response to prostatic stents have been reported. In
total, these combined side effects have historically resulted in 8%
to 47% of prostatic stents to be removed. In addition, these
previous prostatic stents have not had designs which accommodate
the unique characteristics of the prostatic urethra.
[0003] WO2015/138763 describes urethral expanders configured for
implantation into the prostatic urethra and in-situ expansion and
comprising a number of spaced apart interconnected circular ring.
This device suffers from a number of drawbacks including: increased
encrustation due to the circumferential disposition of the rings
meaning that they will meet the urine at 90.degree., difficulty in
removal due to the rings being embedded at 90.degree. to the
longitudinal axis of the urethra; the rings impinging on the
verumontanum which may block some of the ejaculatory and prostatic
ducts; the rigidity and static nature of the ring solution impeding
the natural movements of the prostatic urethra during urination and
ejaculation and causing pain; and the spaced-apart nature of the
rings which effects non-continuous expansion along the length of
the prostatic urethra.
SUMMARY OF THE INVENTION
[0004] Broadly, the invention provides a resiliently deformable
expander that in one embodiment is suitable for the treatment of
benign prostatic hyperplasia (BPH). The expander generally takes
the form of a single elongated undulating ring that is configured
for implantation into a body lumen at a target locus that is
constricted due to adjacent diseased tissue. The undulating ring
has at least two distal prongs and at least two proximal prongs
that are typically configured for invagination into the wall of the
body lumen. The expander is typically resiliently deformable in a
radial direction between a contracted orientation suitable for
transluminal delivery to the target site through the body lumen and
an expanded (deployed) orientation configured to effect in-situ
dilation of the body lumen at the target site. The elongated
undulating ring configuration provides minimal contact area between
the stent and the wall of the body lumen, thereby reducing the
extent of potential encrustation. Further, the struts of the
undulating ring, due to the elongated undulating ring shape, extend
substantially longitudinally (as opposed to circumferentially)
thereby ensuring that flow of fluid is along the struts as opposed
to at right angles to the struts for the majority of the exposed
surface area. This further reduces the incidence of encrustation.
The substantially longitudinal nature of the struts will also
facilitate easier removal. Furthermore, the undulating ring
configuration of the expander allows for differential flexing of
the expander during use, thus allowing the shape of the mirror the
anatomical shape, and adhere to, and move with, the shape of the
wall of the body lumen. In particular, the expander of the
invention does not disrupt the Verumontanum and ejaculatory ducts
and its proximal three projections sit anatomically in the
triangularly shaped distal urethra making migration less likely (as
well as facilitating removal). The undulating ring configuration
also ensures that expansion occurs in the correct anatomical zone
of the urethra (in particular, pushing against the transition zone
of the prostate).
[0005] The expander of the invention provides a means of dilating a
body lumen that has been constricted due to, for example, a
pathological state or due to trauma. One example of a pathology is
benign prostatic hyperplasia, a proliferative disease of the
prostate gland that causes the prostate to constrict around, and
partially block, the prostatic urethra. Thus, in one embodiment,
the invention provides a resiliently deformable expander for the
treatment of benign prostatic hyperplasia (BPH), where the expander
takes the form of an undulating (and preferably sinusoidal) ring
that is configured for implantation into the prostatic urethra
between the bladder neck and external sphincter, that in one
embodiment substantially spans the prostatic urethra between the
bladder neck and external sphincter. In this embodiment, the
undulating ring preferably has at least three distal prongs and at
least three proximal prongs that are suitably configured for
invagination into the wall of the prostatic urethra, and is ideally
resiliently deformable from a relaxed radially expanded orientation
to a radially contracted orientation suitable for transurethral
delivery to a target locus, and when in-situ causes dilation of the
prostatic urethra allowing urine to pass freely through the
prostatic urethra thereby addressing a symptom of BPH. In addition,
the undulating ring configuration of the expander provides minimal
contact area between the expander and the wall of the prostatic
urethra, thereby minimising risk of the stent obstructing the
ejaculatory ducts, and also reducing the extent of encrustation.
The undulating ring configuration also allows for the proximal
stent to fit securely in the distal urethra with the expander's
triangular cross sectional shape matching the triangular cross
sectional shape of the urethra (with each prong sitting in the most
lateral triangular recesses of the urethra. Furthermore, the
undulating ring configuration of the expander allows for
differential flexing of the expander during use, thus allowing the
shape of the expander adhere to, and move with, the shape of the
wall of the wall of the prostatic urethra during exposure to the
different forces experienced during urination and ejaculation.
(i.e. expansion of the urethra during urination and
contraction/spasm of both the bladder neck and the distal
urethra/external sphincter during ejaculation). The location of the
prongs in the triangular recesses will also allow for normal
movement of the urethral wall during contraction.
[0006] Accordingly, in a first aspect, the invention provides an
implantable expander suitable for implantation into a body lumen
and dilation of a constricted section of the body lumen, the
expander comprising an undulating ring that is typically elongated
and comprising at least two proximal prongs and at least two distal
prongs, wherein the expander is typically resiliently deformable
and ideally self-expandable from a radially contracted orientation
suitable for transluminal delivery through the body lumen to a
radially expanded orientation, wherein the expander is configured
to span a substantial part of the constricted section of the body
lumen and cause in-situ expansion of the substantial part of the
constricted section of the body lumen.
[0007] The implantable biocompatible expander of the invention is
suitable for treatment of constrictions of various types of body
lumen, including urinary ducts (such as a urethra or ureter), the
oesophagus and the gastrointestinal tract. Constrictions may be
caused by various pathologies, including benign and malignant
proliferative disorders of the adjacent tissue. In a preferred
embodiment, the expander is configured for use with a urinary duct,
for example to dilate a urinary duct that has been constricted due
to growth in the urinary duct or an adjacent tissue.
[0008] In one embodiment, the invention provides an implantable
biocompatible expander suitable for implantation into a urinary
duct and dilation of a constricted section of the urinary duct, the
expander comprising an elongated undulating ring comprising at
least two proximal prongs and at least two distal prongs, wherein
the expander is resiliently deformable and self-expandable from a
radially contracted orientation suitable for transluminal delivery
through the urinary duct to a radially expanded orientation,
wherein the expander is configured to span a substantial part of
the constricted section of the urinary duct and cause in-situ
expansion of the substantial part of the constricted section of the
urinary duct.
[0009] The expander of the invention is particularly suitable for
treatment of benign prostatic hyperplasia (BPH). Thus, in one
embodiment, the invention provides a provides an implantable
biocompatible expander according to the invention that is suitable
for treatment of benign prostatic hyperplasia, wherein the expander
is configured for implantation into the prostatic urethra between,
and spanning a substantial section of, the prostatic urethra
between, the bladder neck and external sphincter, and wherein the
expander is resiliently deformable and self-expandable from a
radially contracted orientation suitable for transluminal delivery
through the urethra to a radially expanded orientation.
[0010] Preferably, the distal prongs and/or the proximal prongs are
configured for invagination into the wall of the prostatic
urethra,
[0011] In one embodiment, the elongated undulating ring comprises
at least three proximal prongs and at least three distal
prongs.
[0012] In one embodiment, the undulating ring comprises three or
five distal prongs and three or five proximal prongs.
[0013] In one embodiment, the undulating ring comprises three
distal prongs and three proximal prongs. When the indication to be
treated is BPH, the use of three distal and proximal prongs is
ideal as the expander will have a substantially triangular
cross-section which matches the cross section of the prostatic
urethra.
[0014] In one embodiment, the undulating ring comprises five distal
prongs and five proximal prongs.
[0015] In one embodiment, the undulating ring comprises seven
distal prongs and seven proximal prongs.
[0016] In one embodiment, the undulating ring is a sinusoidal
ring.
[0017] The undulating ring typically comprises elongated struts
connecting the distal and proximal prongs and open areas between
the struts and prongs. Suitably the radially outwardly facing
surface of the prongs and struts is less than 10% of the total open
areas. Suitably the radially outwardly facing surface of the prongs
and struts is less than 7% of the total open areas. Suitably the
radially outwardly facing surface of the prongs and struts is less
than 5% of the total open areas. Suitably the radially outwardly
facing surface of the prongs and struts is less than 3% of the
total open areas.
[0018] In one embodiment, the prongs are substantially V-shaped. In
another embodiment, the prongs are substantially U-shaped. In
another embodiment, the prongs are substantially rectangular
shaped.
[0019] In one embodiment, the elongated struts of each prong are
substantially straight. In another embodiment, the elongated struts
of each prong are substantially curved. In one embodiment, the
elongated struts of each prong are curved substantially outwardly.
In one embodiment, the elongated struts of each prong are curved
substantially outwardly. In one embodiment, at least one elongated
strut is curved substantially outwardly and at least one elongated
strut is curved substantially inwardly.
[0020] In one embodiment of the invention, an apex of one of more
of the prongs comprises a loop or lip. Typically, the loop or lip
projects radially into the expander (i.e. the ends of the prongs
flare inwardly). In another embodiment, the loop or lip projects
radially out of the expander (i.e. the ends of the prongs flare
inwardly).
[0021] In one embodiment, the apices of the distal prongs are
unconnected circumferentially. In one embodiment, the apices of the
proximal prongs are unconnected circumferentially.
[0022] In one embodiment, the prongs are longitudinally staggered
with respect to each other. In one embodiment, the prongs are
longitudinally staggered with respect to each other at a distal end
of the expander. In another embodiment, the prongs are
longitudinally staggered with respect to each other at a proximal
end of the expander. In another embodiment, the prongs are
longitudinally staggered with respect to each other at both ends of
the expander.
[0023] In one embodiment, an apex of the distal prongs comprises a
loop or lip that projects generally radially into the expander and
an apex of the proximal prongs comprises a loop or lip that
projects generally radially out of the expander. In another
embodiment, an apex of the distal prongs comprises a loop or lip
that projects generally radially out of the expander and an apex of
the proximal prongs comprises a loop or lip that projects generally
radially into the expander.
[0024] In one embodiment of the invention, an apex of one of more
of the prongs is substantially M-shaped.
[0025] In one embodiment, the expander is formed from a wire, for
example nitinol wire. The wire can have any profile, for example
circular, oval, rectangular, square, or otherwise. In a preferred
embodiment, the profile is circular. The expander may also be
formed by a ribbon. Also, it can be formed by any process, for
example cutting from a tubular structure. In a preferred
embodiment, the expander is formed by laser cutting. In one
embodiment, the expander comprises an anchoring element for
anchoring the expander in-situ within a body lumen. In one
embodiment, the expander comprises at least two anchoring elements.
In one embodiment, the at least two anchoring elements project in
different directions. In one embodiment, the expander comprises at
least one anchoring element disposed at a proximal end of the
expander and at least one anchoring element disposed at a distal
end of the expander. In one embodiment, the anchoring element
comprises a projection, for example a hook, barb, coil, or screw.
In one embodiment of the invention the undulating or sinusoidal
ring comprises a single wire, typically having ends that are joined
at or close to each end. In one embodiment of the invention, one of
the ends of the wire is shaped to form the anchoring element. In
one embodiment of the invention, the anchoring element comprises an
end of the wire that extends beyond a joining point. In one
embodiment of the invention, each end of the wire extends beyond a
joining point, typically co-extensive with the strut of the
expander. In one embodiment, the or each anchoring element, or at
least a part thereof, is biodegradable. This allows the anchoring
element (or a part thereof) biodegrade over time, allowing for ease
of removal after the anchoring element has degraded.
[0026] In one embodiment, the anchoring element comprises a collar
that is configured to embrace a strut and one or more projections
extending from the collar. In one embodiment, the projections are
disposed on each end of the collar. In one embodiment, projections
are disposed on opposite sides of the collar. In one embodiment,
the or each projection is a barb.
[0027] In one embodiment, the elongated sinusoidal ring is
cylindrical, conical, frusto-conical, tapers inwardly at each end
(i.e. barrel shaped), or tapers inwardly towards in mid-section
(i.e. has a waist).
[0028] In one embodiment, the expander is adapted to elute a
pharmaceutically active agent. Examples of pharmaceutically active
agents include tissue growth inhibitors such as alpha reductase
inhibitors or cell proliferation inhibitors such as paclitaxel.
Methods of incorporating drugs into the expander for in-vivo
elution will be apparent to a person skilled in the art and are
described in, for example, U.S. Pat. Nos. 5,591,277, 5,697,967,
5,599,325, US2007/0077266, WO0112779 and WO9013332.
[0029] In another aspect, the invention provides an implantable
biocompatible expander to treat BPH, wherein the expander:
[0030] is configured for resilient deformation and self-expansion
from a radially contracted orientation suitable for transluminal
delivery through a urinary duct (in particular through a urethra)
to a radially expanded orientation capable of effecting in-situ
dilation of the prostatic urethra;
[0031] is typically configured to fit within the prostatic urethra
between the bladder neck and the external sphincter without
blocking the verumontanum;
[0032] is typically configured to anatomically conform to the wall
of prostatic urethra; and
[0033] typically comprises a plurality of longitudinal struts and
is typically free of circumferential struts.
[0034] In another aspect, the invention provides an elongated,
indwelling, expander ring to treat BPH, the expander ring
configured to fit within the prostatic urethra between the bladder
neck and the external sphincter without blocking the verumontanum
and effect in-situ dilation of the prostatic urethra.
[0035] In another aspect, the invention provides an elongated,
indwelling, expander ring to treat BPH, the expander ring
comprising a plurality of longitudinal struts and typically no
circumferential struts configured to allow the expander conform to
the anatomy of the prostatic urethra when expanded without blocking
the verumontanum.
[0036] In one embodiment, the distal end of the expander is
configured to engage the wall of the distal prostatic urethra
without obstructing the verumontanum.
[0037] In one embodiment, the longitudinal struts on a distal end
of the expander are configured to engage the wall of the distal
prostatic urethra without obstructing the verumontanum.
[0038] In one embodiment, the proximal end of the expander is
configured to engage the wall of the proximal prostatic urethra
adjacent the transition zone of the prostate gland.
[0039] In one embodiment, the longitudinal struts on a proximal end
of the expander are configured to engage the wall of the proximal
prostatic urethra adjacent the transition zone of the prostate
gland.
[0040] In one embodiment, the longitudinal struts are configured
for differential flexing of the expander during use (differential
flexing of the distal and proximal ends of the expander), thus
allowing the shape of the expander adhere to, and move with, the
shape of the wall of the body lumen.
[0041] In one embodiment, the longitudinal struts are formed by an
undulating structural element, for example a sinusoidal structural
element. In one embodiment, the structural element is a wire or a
ribbon, for example a metal wire or ribbon.
[0042] In one embodiment, the expander comprises an elongated ring.
In one embodiment, the elongated ring is formed from an undulating
structural element, typically a single undulating structural
element. In one embodiment, the elongated ring is formed from
expansible mesh.
[0043] In another aspect, the invention provides a delivery device
for an expander of the invention comprising a handle operatively
connected to a delivery tube having a hollow distal end remote from
the handle configured to receive an expander of the invention in a
contracted orientation, and an ejection element operatively
connected to the handle and operable to eject the expander from the
open end of the delivery tube. In one embodiment, the delivery tube
is configured for insertion into the urethra through the penis and
for delivery of an expander of the invention into the prostatic
urethra. In another embodiment, the delivery tube is configured for
insertion into the oesophagus through the mouth and for delivery of
an expander of the invention into the oesophagus. In another
embodiment, the delivery tube is configured for insertion into the
colon through the anus and for delivery of an expander of the
invention into the colon. In one embodiment, the ejection element
comprises a head configured to engage a proximal end of the
expander. This allows the ejection element grip the expander and
effect movement of the expander proximally (towards the
handle--retraction) and distally (away from the handle--ejection).
In one embodiment, the head of ejection element comprises a jig
configured to engage the apex of at least one of the proximal
prongs. In one embodiment, the head of ejection element comprises a
jig configured to engage the apex of all of the proximal prongs,
for example two, three, five or seven proximal prongs. In one
embodiment, the head of the ejection element is configured to
extend into a lumen of the proximal end of the expander. In one
embodiment, the head of the ejection element has a cross-sectional
area that matches the cross-sectional area of the body lumen of the
lumen into which the expander is to be inserted. This, when the
expander is radially contracted and inserted into the open end of
the delivery tube, the head of the ejection element is inserted
into the lumen of the proximal end of the expander, forcing the
expander to assume the cross-sectional shape of the head. In the
case of the prostatic urethra, the head of the ejection element
typically has a substantially triangular cross section, and this
forces the expander to assume a generally triangular
cross-sectional shape, substantially matching the cross-sectional
shape of the prostatic urethra. In one embodiment, the head of the
ejection element has a substantially pentagonal cross section. In
one embodiment, the head of the ejection element has a
substantially heptagonal cross section.
[0044] In one embodiment, the delivery device comprises an imaging
device disposed within the hollow distal end of the delivery tube
and configured for imaging the placement of the expander. In one
embodiment the imaging device is disposed within a lumen of the
delivery tube. In one embodiment the imaging device is disposed
concentrically within the lumen of the delivery tube. In one
embodiment, the imaging device comprises a light source configured
to illuminate, in use, a part of the body lumen adjacent the end of
the delivery device. In one embodiment, the imaging device is a
cystoscope.
[0045] In another aspect, the invention relates to a method of
treating a disease or condition characterised by constriction of a
body lumen in a mammal, which method employs an implantable
expander (typically an implantable expander of the invention), the
method comprising the steps of implanting the expander into a
constricted section of the body lumen, whereby the expander in the
expanded orientation effects in-situ dilation of the constricted
section of the body lumen.
[0046] In one embodiment, the method comprises the steps of:
[0047] delivering the expander in a radially contracted orientation
through the body lumen to a target location within the body lumen
characterised by a constricted section of the body lumen;
[0048] and
[0049] allowing the expander expand at the target location to a
radially expanded orientation against the wall of the body lumen,
whereby the expander in the expanded orientation effects in-situ
dilation of the constricted section of the body lumen.
[0050] In one embodiment, the disease or condition characterised by
constriction of a body lumen in a mammal is a proliferative disease
of the urethra.
[0051] In one embodiment, the proliferative disease of the urethra
is benign prostatic hyperplasia.
[0052] In one embodiment, the expander is configured for resilient
deformation and self-expansion from a radially contracted
orientation suitable for transluminal delivery through a urinary
duct to a radially expanded orientation capable of effecting
in-situ dilation of the prostatic urethra
[0053] In one embodiment, the method of the invention employs a
delivery device configured to hold the expander in a radially
contracted orientation, deliver the expander through the body lumen
to the constricted section of the body lumen in the radially
contracted orientation, and release the expander at the constricted
section of the body lumen.
[0054] In one embodiment, the delivery device comprises a handle
including actuation means configured to remotely release the
expander, in which the method includes a step of actuating the
actuation means of the delivery device to remotely release the
expander at the target location within the prostatic urethra.
[0055] In one embodiment, the method of the invention additionally
employs an imaging device suitable for providing an image of the
constricted section of the body lumen, the method comprising the
using the imaging device to correctly position the expander at the
constricted section of the body lumen.
[0056] In one embodiment, the positioning step comprising
longitudinal adjustment of the position of the expander within the
body lumen.
[0057] In one embodiment, the positioning step comprising radial
adjustment of the position of the expander within the body
lumen.
[0058] In one embodiment, the delivery device comprises a light at
a distal end thereof, wherein the step of delivering the expander
to the target location includes a step of guiding the delivery
device and expander to the target location in the body lumen by
external monitoring of the position of the light.
[0059] In one embodiment, the expander is an expander according to
the invention.
[0060] In another aspect, the invention relates to a method of
treating benign prostatic hyperplasia in a mammal, which method
employs an implantable biocompatible expander configured for
resilient deformation and self-expansion from a radially contracted
orientation suitable for transluminal delivery through a urinary
duct to a radially expanded orientation capable of effecting
in-situ dilation of the prostatic urethra, wherein the expander is
configured to fit within the prostatic urethra between the bladder
neck and the external sphincter, the method comprising the steps of
implanting the expander into the prostatic urethra at a target
location between the bladder neck and the external sphincter,
whereby the expander in the radially expanded orientation effects
in-situ dilation of the prostatic urethra between the bladder neck
and the external sphincter.
[0061] In one embodiment, the method comprises the steps of:
[0062] delivering the expander in a radially contracted orientation
through the urethra to the target location within the prostatic
urethra between the bladder neck and the external sphincter;
and
[0063] allowing the expander expand at the target location to a
radially expanded orientation against the wall of the prostatic
urethra.
[0064] In one embodiment, the expander is configured to effect
in-situ dilation of the prostatic urethra at the target location
without blocking the verumontanum.
[0065] In one embodiment, the expander is configured to fit in the
prostatic urethra between the bladder neck and the external
sphincter without inhibiting the function of the bladder neck.
[0066] In one embodiment, the expander is configured to fit in the
prostatic urethra between the bladder neck and the external
sphincter without inhibiting the function of the bladder neck and
the external sphincter.
[0067] In one embodiment, the expander is configured to
anatomically conform to the wall of the prostatic urethra.
[0068] In one embodiment, the expander is resiliently deformable to
conform to the wall of the prostatic urethra as the shape and
topography of the wall changes during, for example, urination or
ejaculation.
[0069] In one embodiment, the method of the invention employs a
delivery device configured to hold the expander in a radially
contracted orientation, deliver the expander through the urethra to
the prostatic urethra in the radially contracted orientation, and
release the expander in the prostatic urethra whereby upon release
the expander self-expands to the radially expanded orientation.
[0070] In one embodiment, the delivery device comprises a handle
including actuation means configured to remotely release the
expander, in which the method includes a step of actuating the
actuation means of the delivery device to remotely release the
expander within the prostatic urethra.
[0071] In one embodiment, the expander is configured to span a
substantial section of the prostatic urethra between the bladder
neck and the external sphincter.
[0072] In one embodiment of a method of the invention, the expander
is configured to anatomically conform to the lumen of the prostatic
urethra.
[0073] In one embodiment, the expander is configured to dilate the
prostatic urethra without blocking the verumontanum. For example,
the expander may comprise a configuration of struts that provides
an opening dimensioned to overlap with the verumontanum.
[0074] In one embodiment, the expander has a longitudinal dimension
of 15 mm to 35 mm.
[0075] In one embodiment, the delivery device comprises a light at
a distal end thereof, wherein the step of delivering the expander
to the prostatic urethra includes a step of guiding the delivery
device by external monitoring of the position of the light. such
that the expander is located between the bladder neck and the
external sphincter.
[0076] In one embodiment, the implantable expander is an
implantable expander of the invention.
[0077] In one embodiment, the implantable expander employed in the
method of the invention comprises a hollow lumen and is configured
for resilient deformation and self-expansion from a radially
contracted orientation suitable for transluminal delivery through
the urinary duct to a radially expanded orientation, wherein the
expander is configured to fit within the prostatic urethra between
the bladder neck and the external sphincter and span a substantial
section of the prostatic urethra without blocking the verumontamum,
the method comprising the steps of:
[0078] delivering the expander in radially contracted orientation
through the urethra to a target location within the prostatic
urethra between the bladder neck and the external sphincter;
and
[0079] allowing the expander expand at the target location to a
radially expanded orientation against the wall of the prostatic
urethra, whereby the expander in the expanded orientation effects
in-situ dilation of the prostatic urethra at the target location
without blocking the verumontanum and preserves the function of the
bladder neck.
[0080] In one embodiment, in-situ expansion of the expander
includes a step of placing a radially expansible member in the
lumen of the expander and radially expanding the member to effect
expansion of the expander in the prostatic urethra. The radially
expansible member may be a balloon.
BRIEF DESCRIPTION OF THE DRAWINGS
[0081] The foregoing will be apparent from the following more
particular description of example embodiments of the invention, as
illustrated in the accompanying drawings in which like reference
characters refer to the same parts throughout the different views.
The drawings are not necessarily to scale, emphasis instead being
placed upon illustrating embodiments of the present invention.
[0082] FIG. 1 is an elevational view of a three-prong expander of
the invention in a relaxed, expanded, state;
[0083] FIG. 2 is an elevational view of a three-prong expander of
FIG. 1 in a contracted state;
[0084] FIG. 3 is a partly sectional view of the expander of FIG. 1
disposed within the prostatic urethra of a patient with benign
prostatic hyperplasia in which the expander is exerting an outward
radial pressure on the walls of the prostatic urethra causing
dilation;
[0085] FIG. 4 is a partly sectional view similar to FIG. 2 showing
the seminal vesicle and an ejaculatory duct entering the prostatic
urethra;
[0086] FIG. 5 is a photograph of an expander of the invention
in-situ within a prostatic urethra showing the three proximal
prongs and three distal prongs;
[0087] FIG. 6 is an elevational view of a five-prong expander
according to the invention;
[0088] FIG. 7 is an elevational view of a three prong expander
according to the invention comprising a tapered sinusoidal
ring;
[0089] FIG. 8 is an elevational view of a three prong expander
according to the invention comprising a barrel-shaped sinusoidal
ring;
[0090] FIG. 9 is an elevational view of a three prong expander
according to the invention comprising in which the apices of the
prongs are flared outwardly;
[0091] FIG. 10 is an elevational view of a three prong expander
according to the invention in which the apices of the distal prongs
are flared outwardly;
[0092] FIG. 11 is an elevational view of a three prong expander
according to the invention in which the apices of the distal prongs
comprise an inwardly flared loop and the apices of the proximal
prongs comprise an outwardly flared loop;
[0093] FIG. 12 is an elevational view of a three prong expander
according to the invention similar to the expander of FIG. 12 and
in which the distal prongs are offset in height and the proximal
prongs are offset in height to allow the distal and proximal loops
dovetail when the expander is in a contracted orientation;
[0094] FIG. 13 is an elevational view of the three-prong expander
of FIG. 12 shown in a contracted orientation;
[0095] FIG. 14 is an elevational view of a three-prong expander of
the invention having looped apices on the distal and proximal
prongs;
[0096] FIG. 15 is an elevational view of a three prong expander of
the invention in which the struts of the distal prongs have a
greater thickness that the struts of the proximal prongs;
[0097] FIG. 16 is an elevational view of a three prong expander of
the invention in which the apices of the distal prongs are formed
into an M-formation, and in which an end of the wire extends beyond
one of the apices to provide a fixation barb;
[0098] FIG. 17 is an elevational view of a three-prong expander of
the invention in which an end of the wire extends beyond one of the
apices to provide a coil having a barbed end;
[0099] FIG. 18 is an elevational view of a three-prong expander of
the invention in which each end of the wire extends longitudinally
beyond the ends of the expander to provide distal and proximal
barbs;
[0100] FIG. 19 is an elevational view of the three-prong expander
of FIG. 1 having an anchoring element disposed on one of the
longitudinal struts;
[0101] FIG. 20 is an elevational view of a three-prong expander of
the invention in which each end of the wire extends longitudinally
beyond the ends of the expander to provide distal and proximal
barbs that extend circumferentially partially around each end of
the expander;
[0102] FIG. 21 is an elevational view of a three-prong expander of
the invention in which four of the struts are substantially linear
and four of the struts are non-linear;
[0103] FIG. 22 is an elevational view of a two-prong expander of
the invention shown in a relaxed expanded state;
[0104] FIG. 23 is an elevational view of the two-prong expander of
FIG. 22 in which two of the longitudinal prongs comprise anchoring
elements;
[0105] FIG. 24 is an elevational view of an alternative embodiment
of two-prong expander of the invention shown in a relaxed expanded
state;
[0106] FIG. 25 is an elevational view of an anchoring element shown
disposed on a strut of an expander of the invention;
[0107] FIG. 26 is an elevational view of a further embodiment of
anchoring element shown disposed on a strut of an expander of the
invention;
[0108] FIG. 27 is an elevational view of a further embodiment of
anchoring element shown disposed on a strut of an expander of the
invention;
[0109] FIG. 28 is an elevational view of a further embodiment of
anchoring element shown disposed on a strut of an expander of the
invention;
[0110] FIG. 29 is an elevational view of a delivery device for an
expander of the invention prior to insertion of the expander;
[0111] FIG. 30 is an elevational view of the delivery device of
FIG. 20 showing the expander in-situ within the distal end of the
device in a contracted orientation;
[0112] FIG. 31 is an elevational view of the delivery device of
FIG. 20 showing the expander in-situ within the prostatic urethra
after ejection from the distal end of the device; and
[0113] FIG. 32 is an elevational view of a distal end of an
ejection element forming part of the delivery device of FIG.
29.
[0114] FIGS. 33A, 33B, 33C and 33D illustrate a delivery device of
the invention incorporating a cystoscope disposed concentrically
with a lumen of the delivery device in use delivering an expander
of the invention in the prostatic urethra.
[0115] FIG. 34 is a 3-D X-ray image showing an expander of the
invention in-situ in the prostatic urethra of a canine.
[0116] FIGS. 35 and 36 are photographs showing an expander of the
invention deployed in the prostatic urethra of a canine. The
verumontanum is the ridge at six o'clock in the photos.
[0117] FIG. 37 illustrates a method of treating benign prostatic
hyperplasia (BPH).
[0118] FIG. 38 illustrates an expander of the invention deployed in
the prostatic urethra of a patent with BPH, between the bladder
neck muscle and the external sphincter. This figure shows how the
device accommodates the verumontanum between two prongs of the
expander in the distal prostatic urethra, which the proximal end of
the device is configured such that one of the prongs pushes the
transition zone of the prostate gland away from the lumen of the
prostatic urethra.
DETAILED DESCRIPTION OF THE INVENTION
[0119] A description of example embodiments of the invention
follows.
[0120] The teachings of all patents, published applications and
references cited herein are incorporated by reference in their
entirety.
[0121] Where used herein and unless specifically indicated
otherwise, the following terms are intended to have the following
meanings in addition to any broader (or narrower) meanings the
terms might enjoy in the art:
[0122] Unless otherwise required by context, the use herein of the
singular is to be read to include the plural and vice versa. The
term "a" or "an" used in relation to an entity is to be read to
refer to one or more of that entity. As such, the terms "a" (or
"an"), "one or more," and "at least one" are used interchangeably
herein.
[0123] As used herein, the term "comprise," or variations thereof
such as "comprises" or "comprising," are to be read to indicate the
inclusion of any recited integer (e.g. a feature, element,
characteristic, property, method/process step or limitation) or
group of integers (e.g. features, element, characteristics,
properties, method/process steps or limitations) but not the
exclusion of any other integer or group of integers. Thus, as used
herein the term "comprising" is inclusive or open-ended and does
not exclude additional, unrecited integers or method/process
steps.
[0124] As used herein, the term "disease" is used to define any
abnormal condition that impairs physiological function and is
associated with specific symptoms. The term is used broadly to
encompass any disorder, illness, abnormality, pathology, sickness,
condition or syndrome in which physiological function is impaired
irrespective of the nature of the aetiology (or indeed whether the
aetiological basis for the disease is established). It therefore
encompasses conditions arising from infection, trauma, injury,
surgery, radiological ablation, poisoning or nutritional
deficiencies.
[0125] As used herein, the term "treatment" or "treating" refers to
an intervention (e.g. the administration of an agent to a subject)
which cures, ameliorates or lessens the symptoms of a disease or
removes (or lessens the impact of) its cause(s) (for example, the
reduction in accumulation of pathological levels of lysosomal
enzymes). In this case, the term is used synonymously with the term
"therapy".
[0126] Additionally, the terms "treatment" or "treating" refers to
an intervention (e.g. the administration of an agent to a subject)
which prevents or delays the onset or progression of a disease or
reduces (or eradicates) its incidence within a treated population.
In this case, the term treatment is used synonymously with the term
"prophylaxis".
[0127] As used herein, an effective amount or a therapeutically
effective amount of an agent defines an amount that can be
administered to a subject without excessive toxicity, irritation,
allergic response, or other problem or complication, commensurate
with a reasonable benefit/risk ratio, but one that is sufficient to
provide the desired effect, e.g. the treatment or prophylaxis
manifested by a permanent or temporary improvement in the subject's
condition. The amount will vary from subject to subject, depending
on the age and general condition of the individual, mode of
administration and other factors. Thus, while it is not possible to
specify an exact effective amount, those skilled in the art will be
able to determine an appropriate "effective" amount in any
individual case using routine experimentation and background
general knowledge. A therapeutic result in this context includes
eradication or lessening of symptoms, reduced pain or discomfort,
prolonged survival, improved mobility and other markers of clinical
improvement. A therapeutic result need not be a complete cure.
[0128] In the context of treatment and effective amounts as defined
above, the term subject (which is to be read to include
"individual", "animal", "patient" or "mammal" where context
permits) defines any subject, particularly a mammalian subject, for
whom treatment is indicated. Mammalian subjects include, but are
not limited to, humans, domestic animals, farm animals, zoo
animals, sport animals, pet animals such as dogs, cats, guinea
pigs, rabbits, rats, mice, horses, cattle, cows; primates such as
apes, monkeys, orangutans, and chimpanzees; canids such as dogs and
wolves; felids such as cats, lions, and tigers; equids such as
horses, donkeys, and zebras; food animals such as cows, pigs, and
sheep; ungulates such as deer and giraffes; and rodents such as
mice, rats, hamsters and guinea pigs. In preferred embodiments, the
subject is a human.
[0129] "Implantable" as applied to an expander of the invention
means a device that is formed of materials that are biocompatible,
i.e. do not normally promote an immune response in the host and/or
cause trauma, inflammation or scarring. Examples of such materials
include gold, titanium, cobalt-chromium alloy, tantalum alloy,
nitinol, and several polymers.
[0130] "Expander" means a biocompatible device having a lumen to
allow for flow of liquid past the expander and that is resiliently
deformable and self-expandable between a relaxed, expanded
orientation and a contracted orientation suitable for transluminal
delivery, and sometimes percutaneous delivery, whereby when in-situ
the expander exerts an outward radial force against the walls of
the body lumen. The expander usually take a generally cylindrical
form and may be configured to conform to the shape of a section of
a body lumen. Expanders for body lumen such as arteries, veins and
urethras are known in the literature, for example WO2015138763,
CN202822454, and U.S. Pat. No. 5,269,802. The expander may be made
from any suitable material for example stainless steel, a shape
memory polymer (for example a linear block copolymer or other
thermoplastic polymers having shape memory effect), and a shape
memory alloy (i.e. nitinol).
[0131] "Body lumen" means an elongated tubular organ within the
body, including urinary ducts, gastrointestinal tract, oesophagus,
and vasculature. "Urinary duct" means a urethra or ureter.
[0132] "Undulating ring" means a ring shaped device formed from a
structural element such as a wire shaped in a wave-like form and
having at least two distal prongs and at least two proximal prongs
(see FIGS. 1 to 24). The undulating structural element may take a
substantially sinusoidal wave form (a sinusoidal ring), a
substantially square wave form (a square wave ring), a wave form
that is intermediate a sinusoidal wave form and square wave form,
and any combination of these wave forms. In one embodiment, the
undulating ring has a substantially periodic wave form. In one
embodiment, the undulating ring has a non-periodic wave form. In
one embodiment, the prongs are substantially V-shaped. In one
embodiment, the prongs are substantially rectangular shaped. In a
preferred embodiment, the undulating ring is a sinusoidal ring. In
a preferred embodiment, the undulating ring has three distal prongs
and three proximal prongs. An undulating ring having three distal
and proximal prongs is particularly suitable for treatment of
benign prostatic hyperplasia. In one embodiment, at least one of
the prongs forms two or more sub-prongs, for example a prong may be
W-shaped to form two sub-prongs. In one embodiment, the undulating
ring has a width (in a relaxed state) that is greater than the
width of the diseased prostatic urethra. In one embodiment, the
undulating ring has a width (in a relaxed state) that is 5-40%
greater than the width of the diseased prostatic urethra. In one
embodiment, the undulating ring has a width (in a relaxed state)
that is 10-30% greater than the width of the diseased prostatic
urethra.
[0133] "Elongated undulating ring" means an undulating ring that
has a longitudinal dimension that is equal to or greater than its
maximal transverse dimension when in a relaxed, expanded, state.
Typically, the maximal longitudinal dimension is greater than its
maximal transverse dimension when in a relaxed, expanded, state.
Generally, the undulating ring has a length of 10-45 mm. Typically,
the undulating ring has a width (in a relaxed state) of 6-30 mm. In
one embodiment, the undulating ring has a length of 15-25 mm. In
one embodiment, the undulating ring has a width (in a relaxed
state) of 10-20 mm. In one embodiment, the length of the undulating
ring is at least 10% greater than the width of the undulating ring
(in a relaxed state). In one embodiment, the length of the
undulating ring is at least 20% greater than the width of the
undulating ring (in a relaxed state). In one embodiment, the length
of the undulating ring is at least 30% greater than the width of
the undulating ring (in a relaxed state). In one embodiment, the
length of the undulating ring is at least 40% greater than the
width of the undulating ring (in a relaxed state). In one
embodiment, the length of the undulating ring is 1-40% greater than
the width of the undulating ring (in a relaxed state). In one
embodiment, the length of the undulating ring is 5-40% greater than
the width of the undulating ring (in a relaxed state). In one
embodiment, the length of the undulating ring is 5-30% greater than
the width of the undulating ring (in a relaxed state). In one
embodiment, the length of the undulating ring is 5-20% greater than
the width of the undulating ring (in a relaxed state).
[0134] "Proximal prongs" refers to the prongs that are disposed at
the delivery side of the body lumen when the expander is in-situ
within the body lumen. "Distal prongs" refers to the prongs that
are disposed opposite to the delivery side of the body lumen when
the expander is in-situ within the body lumen. In the case of an
extender of the invention for that is configured for treatment of
BPH, the proximal prongs will typically lie adjacent to the
external sphincter, and the distal prongs will typically lie
adjacent to the bladder neck.
[0135] "Resiliently deformable and self-expandable" means that the
expander can be radially compressed into a contracted orientation
(suitable for transluminal delivery) and upon release of the
compression forces will assume a relaxed expanded orientation. In
this manner, the expander is delivered using a suitable delivery
vehicle in a contracted orientation and the compression forces are
released in-situ at a target site allowing the expander exert
outward radial forces against the wall of the body lumen.
Generally, the width of the expander in the relaxed state is
greater than the width of the target body lumen. Various delivery
means are suitable, for example a delivery tube having a hollow tip
dimensioned to receive and hold the expander in a contracted
orientation, whereby upon ejection from the delivery tube the
expander expands. Other delivery means include a catheter having an
outer sheath that during delivery embraces the expander and when
in-situ is withdrawn allowing the expander expand. In one
embodiment, the expander can be contracted to a cross-sectional
area of less than 50% of the cross-sectional area of the expander
in its relaxed state. In one embodiment, the expander can be
contracted to a cross-sectional area of less than 40% of the
cross-sectional area of the expander in its relaxed state. In one
embodiment, the expander can be contracted to a cross-sectional
area of less than 30% of the cross-sectional area of the expander
in its relaxed state. In this regard, "cross-sectional area" means
a cross-section area taken through a mid-point of the expander and
defined by the longitudinal struts.
[0136] "Radially contracted orientation suitable for transluminal
delivery" means that the expander is radially contracted to bring
the prongs close together thereby significantly reducing the
transverse profile of the ring such that it can be delivered
through the body lumen.
[0137] "Relaxed radially expanded orientation" means that the
profile of the expander when it is in a relaxed state.
[0138] "Substantial section of the prostatic urethra" means at
least 30% of the length of the prostatic urethra between the
bladder neck and external sphincter. In one embodiment, the
undulating ring is configured to span at least 40% of the length of
the prostatic urethra between the bladder neck and external
sphincter. In one embodiment, the undulating ring is configured to
span at least 50% of the length of the prostatic urethra between
the bladder neck and external sphincter. In one embodiment, the
undulating ring is configured to span at least 60% of the length of
the prostatic urethra between the bladder neck and external
sphincter. In one embodiment, the undulating ring is configured to
span at least 70% of the length of the prostatic urethra between
the bladder neck and external sphincter.
[0139] "Self-expansion" as applied to the resiliently deformable
expander means that the expander is adjustable between a radially
expanded and a radially contracted configuration and biased into
the radially expanded configuration.
[0140] "Disease or condition characterised by constriction of a
body lumen in a mammal" means for example proliferative conditions
such as benign prostatic hyperplasia, or other proliferative or
non-proliferative conditions such as inflammation, associated with
a body lumen and which cause constriction or mis-shaping, and
partial or complete blockage of the body lumen. In one embodiment
the body lumen is a body lumen of the renal system, for example a
urethra or ureter. In one embodiment, the mammal is a human for
example a male human or a female human. In one embodiment, the
condition is inflammation of the body lumen. In one embodiment, the
condition is inflammation of the ureter or urethra (for example
caused by trauma or a renal stone). In one embodiment, the
condition is incontinence, for example stress urinary incontinence.
In this embodiment, the expander is generally placed in the urethra
between the bladder neck and the external sphincter (typically for
the purpose of re-shaping the prostatic urethra).
[0141] "Target location" as applied to a method of treating benign
prostatic hyperplasia means a section of the prostatic urethra
between the bladder neck and the external sphincter that spans a
substantial section of the prostatic urethra including a
constricted section. Typically, the target location is spaced at
least 5 mm from both the external sphincter and the bladder neck.
Typically, the target location is spaced at least 10 mm from both
the external sphincter and the bladder neck.
[0142] "Without inhibiting the function of the bladder neck" as
applied to the expander means that the expander when correctly
positioned in the prostatic urethra between the bladder neck and
the external sphincter does not affect the functioning of the
bladder neck allowing the neck open and close in a normal manner
during urination and tonically contract during ejaculation.
[0143] "Without inhibiting the function of the external sphincter"
as applied to the expander means that the expander when correctly
positioned in the prostatic urethra between the bladder neck and
the external sphincter does not affect the functioning of the
external sphincter allowing the sphincter to rhythmically
contract/spasm during ejaculation. This is the muscle that propels
the ejaculate in the normal antegrade fashion (the spasm of the
external sphincter in conjunction with the tight closing of the
bladder neck means the ejaculate is propelled forward to the
penis).
[0144] "Verumontanum" (or seminal colliculus) is a distinctive
median elevation on the posterior wall of the prostatic urethra. It
is an important landmark as it contains the slit-like openings of
the ejaculatory ducts (containing semen) and the openings of the
prostatic ducts (containing prostatic fluid).
[0145] "Without blocking the nerumontanum" as applied to the
expander means that the expander is configured such that when it is
deployed in an expanded orientation within the prostatic urethra
between the bladder neck and external sphincter it does not block
the verumontanum and lessens or completely avoids disruption,
compression or damage of the Verumontanum that can cause
dysfunction in emission of semen into the prostatic urethra.
[0146] "Imaging device" means a device that can remotely image the
urethra from outside the body. Examples include ultrasound and CT
scanners.
[0147] "Anatomically conform" as applied to the expander means that
the expander is configured to confirm to the wall of the prostatic
urethra. In one embodiment, it means that the expander is
deformable to conform to the wall of the prostatic urethra as the
shape and topography of the wall changes during, for example,
urination or ejaculation.
[0148] Examplification:
[0149] The invention will now be described with reference to
specific Examples. These are merely exemplary and for illustrative
purposes only: they are not intended to be limiting in any way to
the scope of the monopoly claimed or to the invention described.
These examples constitute the best mode currently contemplated for
practicing the invention.
[0150] Referring to the drawings, and initially to FIG. 1, there is
illustrated an expander according to the invention indicated
generally by the reference numeral 1. The expander 1 comprises a
single nitinol wire configured as an elongated sinusoidal ring
having a distal end 3 comprising three distal prongs 4 with apices
5 and a proximal end 6 having three proximal prongs 7 with apices
8. The prongs are connected by longitudinal struts 9. The expander
1 is shown in an expanded, relaxed, state and has a length of
approximately 22 mm and a width of approximately 15 mm. In the
expanded state shown, the distance between the apices 5 of adjacent
distal prongs 4 at the distal end 3 of the expander is
approximately 14 mm. Likewise, the distance between the apices 8 of
adjacent proximal prongs 7 at the proximal end 6 of the expander is
approximately 14 mm. The nitinol wire has a cross-sectional
diameter of approximately 0.4 mm.
[0151] Referring to FIG. 2, the expander 1 is shown in a radially
contracted state in which the distal and proximal prongs are
brought together. In this contracted state, the cross-sectional
area of the expander is reduced by more than 70% compared with the
relaxed expanded state shown in FIG. 1, and the distance between
adjacent distal and proximal prongs has reduced from 14 mm to 4-5
mm. In this contracted configuration, the resilient deformability
of the sinusoidal ring configuration causes the ring to exert an
outward radial force.
[0152] Referring to FIGS. 3 and 4 there is illustrated an expander
of FIG. 1 shown in use in the treatment of benign prostatic
hyperplasia. The expander 1 is disposed within the prostatic
urethra 10 within the prostate gland 11 in between the bladder neck
12 and the external sphincter 13. In this position, the expander 1
exerts an outward radial force against the walls of the prostatic
urethra 10 expanding the urethra to allow flow of urine. Due to the
sinusoidal ring design, the outward radial force is greatest at
each end of the expander, adjacent the transition zones of the
prostatic urethra, where the greatest amount of diseased tissue is
located. In addition, due to the design of the expander, the
contact area between the struts and prongs of the expander and the
wall of the prostatic urethra is minimised so that the seminal
ducts 15 are not obstructed by the walls of the expander. In
addition, as the expander does not have any circumferential struts,
removal of the expander is facilitated.
[0153] FIG. 5 is a picture of the expander of the invention
inserted into the prostatic urethra of a cadaver, showing the
proximal end of the expander in the foreground and the distal end
of the expander in the background abutting the bladder neck. The
picture illustrates how the struts of the expander are invaginated
into the wall of the prostatic urethra.
[0154] Referring to FIG. 6, there is illustrated an elevational
view of an expander according to an alternative embodiment of the
invention in which parts described with reference to the previous
embodiments are assigned the same reference numerals. In this
embodiment, the expander 20 has five distal prongs 4 and five
proximal prongs 7, and the use of this embodiment is the same as
that described with reference to the previous embodiment.
[0155] Referring to FIG. 7, there is illustrated an elevational
view of an expander according to an alternative embodiment of the
invention in which parts described with reference to the previous
embodiments are assigned the same reference numerals. In this
embodiment, the expander 30 has three distal prongs 4 and three
proximal prongs 7, and is longitudinally inwardly tapered towards
the distal end 3 with the struts having an angle of between
5.degree. and 15.degree. with the longitudinal axis of the expander
when in a relaxed state. The use of this embodiment is the same as
that described with reference to the previous embodiment.
[0156] Referring to FIG. 8, there is illustrated an elevational
view of an expander according to an alternative embodiment of the
invention in which parts described with reference to the previous
embodiments are assigned the same reference numerals. In this
embodiment, the expander 40 has three distal prongs 4 and three
proximal prongs 7, and the struts are curved outwardly along their
length so that the expander has a substantially barrel shape along
its length. The use of this embodiment is the same as that
described with reference to the previous embodiment.
[0157] Referring to FIG. 9, there is illustrated an elevational
view of an expander according to an alternative embodiment of the
invention in which parts described with reference to the previous
embodiments are assigned the same reference numerals. In this
embodiment, the expander 50 has three distal prongs 4 and three
proximal prongs 7, and the struts are curved inwardly along their
length so that the expander has a substantially waisted shape along
its length, with a narrowed central portion 51 and slightly widened
ends 3, 6. In addition, the apices 5, 8 at each end are flared
outwardly. The use of this embodiment is the same as that described
with reference to the previous embodiment.
[0158] Referring to FIG. 10, there is illustrated an elevational
view of an expander according to an alternative embodiment of the
invention in which parts described with reference to the previous
embodiments are assigned the same reference numerals. In this
embodiment, the expander 60 has five distal prongs 4 and five
proximal prongs 7, and the apices 5 at the distal end 3 are flared
outwardly. The use of this embodiment is the same as that described
with reference to the previous embodiment.
[0159] Referring to FIG. 11, there is illustrated an elevational
view of an expander according to an alternative embodiment of the
invention in which parts described with reference to the previous
embodiments are assigned the same reference numerals. In this
embodiment, the expander 70 has three distal prongs 4 and three
proximal prongs 7. The apices 5 at the distal end 3 are formed into
loops 71 that project radially inwardly, and the apices 8 at the
proximal end 6 are formed into loops 72 that project radially
outwardly. The use of this embodiment is the same as that described
with reference to the previous embodiment.
[0160] Referring to FIGS. 12 and 13, there is illustrated an
elevational view of an expander according to an alternative
embodiment of the invention in which parts described with reference
to the previous embodiments are assigned the same reference
numerals. In this embodiment, the expander 80 has three distal
prongs 4 and three proximal prongs 7. The apices 5 at the distal
end 3 are formed into loops 81 that project radially inwardly, and
the apices 8 at the proximal end 6 are formed into loops 82 that
project radially outwardly. In addition, the longitudinal position
of the distal and proximal prongs is offset enabling the loops 81
to dovetail when the expander is in a contracted orientation (shown
in FIG. 13). The use of this embodiment is the same as that
described with reference to the previous embodiment.
[0161] Referring to FIG. 14, there is illustrated an elevational
view of an expander according to an alternative embodiment of the
invention in which parts described with reference to the previous
embodiments are assigned the same reference numerals. In this
embodiment, the expander 90 has three distal prongs 4 and three
proximal prongs 7. The apices 5 at the distal end 3 are formed into
loops 91 that project along a longitudinal axis of the expander,
and the apices 8 at the proximal end 6 are formed into loops 92
that project along a longitudinal axis of the expander. In
addition, the struts are curved outwardly. The use of this
embodiment is the same as that described with reference to the
previous embodiment.
[0162] Referring to FIG. 15, there is illustrated an expander
according to an alternative embodiment of the invention in which
parts described with reference to the previous embodiments are
assigned the same reference numerals. In this embodiment, the
expander 100 is formed of a nitinol wire that has a varying thick
ness along its length, with the portions of the wire forming the
distal prongs 4 being thicker that the portion of the wire that
forms the proximal prongs 7. The use of this embodiment is the same
as that described with reference to the previous embodiment.
[0163] Referring to FIG. 16, there is illustrated an elevational
view of an expander according to an alternative embodiment of the
invention in which parts described with reference to the previous
embodiments are assigned the same reference numerals. In this
embodiment, the expander 110 has three distal prongs 4 and three
proximal prongs 7. The apices 5 at the distal end 3 comprise
M-shaped loops 111 that project along a longitudinal axis of the
expander. In addition, the nitinol wire has an end 112 that extends
beyond the distal end 3 of the expander and comprises a terminal
barb 113 for fixing the expander in place (anchoring element). The
use of this embodiment is the same as that described with reference
to the previous embodiment.
[0164] Referring to FIG. 17, there is illustrated an elevational
view of an expander according to an alternative embodiment of the
invention in which parts described with reference to the previous
embodiments are assigned the same reference numerals. This
embodiment is similar to that of FIG. 16 with the exception that
the end of the nitinol wire forms two helical loops 114 and
terminates in a barb 113 for fixing the expander in place
(anchoring element). The use of this embodiment is the same as that
described with reference to the previous embodiment.
[0165] Referring to FIG. 18, there is illustrated an elevational
view of an expander according to an alternative embodiment of the
invention in which parts described with reference to the previous
embodiments are assigned the same reference numerals. In this
embodiment, the expander 120 has three distal prongs 4 and three
proximal prongs 7 and is formed from a nitinol wire that overlaps
at a joining point 121 and has ends 122 and 123 that extend
longitudinally beyond the ends of the expander and comprise
terminal barbs 124 for fixing the expander in place (anchoring
element). The use of this embodiment is the same as that described
with reference to the previous embodiment.
[0166] Referring to FIG. 19, there is illustrated an elevational
view of an expander according to an alternative embodiment of the
invention in which parts described with reference to the previous
embodiments are assigned the same reference numerals. In this
embodiment, the expander comprises an anchoring element 126
disposed on a longitudinal strut 9, the anchoring element
comprising a strut-embracing sleeve 127 and upwardly projecting
barbs 128.
[0167] Referring to FIG. 20, there is illustrated an elevational
view of an expander according to an alternative embodiment of the
invention in which parts described with reference to the previous
embodiments are assigned the same reference numerals. This
embodiment is similar to that of FIG. 18 with the exception that
the ends 122 and 123 extend substantially circumferentially around
each end of the expander and comprise terminal barbs 124 for fixing
the expander in place. The use of this embodiment is the same as
that described with reference to the previous embodiment.
[0168] Referring to FIG. 21, there is illustrated an elevational
view of an expander according to an alternative embodiment of the
invention in which parts described with reference to the previous
embodiments are assigned the same reference numerals. In this
embodiment, the expander 130 has three distal prongs 4 and three
proximal prongs 7, and is longitudinally inwardly tapered towards
the distal end 3 with the struts having an angle of between 5 and
15 degrees with the longitudinal axis of the expander when in a
relaxed state. In addition, two adjacent struts 131 are cranked
inwardly intermediate their ends providing a different angular
spacing between the struts. The use of this embodiment is the same
as that described with reference to the previous embodiment.
[0169] Referring to FIG. 22, there is illustrated an elevational
view of an expander according to an alternative embodiment of the
invention in which parts described with reference to the previous
embodiments are assigned the same reference numerals. In this
embodiment, the expander 150 is substantially the same as the
expander illustrated in FIG. 1 with the exception that the expander
comprises two distal and proximal prongs 4, 7 instead of three. The
operation of this embodiment is the same as the embodiment of FIG.
1.
[0170] Referring to FIG. 23, there is illustrated the expander of
FIG. 22 having anchoring elements 126 disposed on longitudinal
struts 9. Each anchoring element 126 comprises a sleeve 127 that
embraces a strut 9 and a pair of barbs 128 that project away from
the strut at right angles to each other.
[0171] Referring to FIG. 24, there is illustrated an elevational
view of an expander according to an alternative embodiment of the
invention in which parts described with reference to the previous
embodiments are assigned the same reference numerals. In this
embodiment, the expander 150 is substantially the same as the
expander illustrated in FIG. 22 with the exception that the apices
of the distal prongs 4 are rounded.
[0172] Referring to FIGS. 25 to 28, there is illustrated a number
of embodiments of anchoring elements 126, each comprising a sleeve
127 configured to embrace a strut 9 of an expander of the
invention, and having barbs 128 that project away from the strut
and when in-situ engage a wall of a body lumen. In the embodiment
of FIG. 25, the barbs 128 are mounted at each end of a top of the
sleeve 127 and project upwardly away from the strut at an angle of
roughly 45 to the strut. In the embodiment of FIG. 26, one of the
barbs 128 projects from a top of one end of the sleeve 127 and the
other barb 128 projects from a bottom of an opposite end of the
expander. In the embodiment of FIG. 27, the barbs 128 are cut-out
from the top of the sleeve 127. In the embodiment of FIG. 28, a
wire 129 is mounted to an inside of the sleeve 127 with each end of
the wire 129 projecting proud of the sleeve forming the barbs
128.
[0173] Referring to FIGS. 29 to 31, there is illustrated a delivery
device for delivering an expander of the invention to a target site
within a body lumen, in this case delivery to the prostatic
urethra. The device 200 comprises a handle 201, a delivery tube 202
having a having a hollow distal end 203 remote from the handle 201
configured to receive an expander of the invention in a contracted
orientation, and an ejection element 205 operatively connected to
the handle 201 and operable to eject a stent from the open end of
the delivery tube. In more detail, the ejection means 205 comprises
a shunt mechanism having a distal end 206 operatively connected to
actuation means 207 on the handle and a proximal end disposed
adjacent the distal end 203 of the tube 202. In use, the shunt
mechanism is retracted and the expander 1 is compressed manually
into a contracted shape and inserted into the hollow distal end of
the delivery tube (FIG. 30). The delivery tube is then inserted
into the urethra through the penis and advanced along the urethra
until the distal end of the delivery tube is located within the
prostatic urethra 10. The actuation means 207 on the handle is then
actuated to extend the shunt mechanism and eject the expander 1
from the delivery tube into the prostatic urethra, where it expands
to exert a radially outward pressure against the wall of the
prostatic urethra (FIG. 31). The delivery tube is then retracted
from the urethra.
[0174] Referring to FIG. 32, there is provided a detailed
elevational view of part of the delivery device 200 of FIG. 29. In
this embodiment, the ejection element 205 includes a distal head
210 having a triangular cross-section and configured to fit within
a lumen of the expander when it is mounted within the delivery tube
202. Each of the three faces of the head 210 include a projection
211 together forming a jig for positioning and engaging the
expander within the delivery tube, each projection 211 being
configured to engage an apex of a proximal prong of the expander.
The manner of operation is the same as that described with
reference to the embodiment of FIGS. 29 to 31, with the exception
that the jig engages the expander enabling the ejection element
both push and pull the expander along the delivery tube. This
enables a surgeon partially eject the expander into the body lumen
and then retract the expander if they feel that it is not in the
correct position.
[0175] Referring to FIGS. 33A to 33D, there is illustrated a
delivery device of the invention 300 in use delivering an expander
of the invention 1 into the prostatic urethra 10 which is
surrounded by the prostate gland 11 and disposed distally of the
bladder 301. The delivery device 300 includes a cystoscope 302
disposed concentrically within a lumen of the delivery device 300
and having a distal end substantially flush with a distal end of
the delivery tube 202. As shown in FIG. 33A, the expander is
mounted within the delivery tube 202 with the cystoscope 302
projecting through a lumen of the expander. The cystoscope
comprises a light that illuminates the urethra distally of the end
of the delivery device, thereby assisting a surgeon remotely image
the urethra prior to deployment of the expander (FIG. 33B), and
image the urethra and expander during deployment (FIG. 33C), and
after deployment (FIG. 33D), of the expander.
[0176] Referring to FIG. 37, a method of treating benign prostatic
hyperplasia (BPH) is illustrated, in which an expander 300 is
implanted into the prostatic urethra 310 between the bladder neck
312 and the external sphincter 313. The expander is capable of
self-expansion between a radially contracted configuration (not
shown, but employed during deployment) and a radially expanded
configuration (shown) in which the expander dilates the prostatic
urethra thereby relieving the patient of some of the symptoms of
benign prostatic hyperplasia, in particular it widens the narrowed
urethra, providing less resistance to urine during urination and
allows the urine to pass through the diseased prostatic urethra
(whereas before it would have encountered a narrowed, high pressure
lumen). The expander is configured to fit in the prostatic urethra
between the bladder neck 312 and external sphincter 313, so that it
does not inhibit the function of either. As ejaculation requires
the bladder neck to tonically contract and the external sphincter
to spasm, the expander when properly positioned between the bladder
neck and external sphincter allows for both of these functions, and
thereby addresses one of the drawbacks of known implants for
treating BPH, impaired ejaculation and sexual dysfunction.
Moreover, as the function of the bladder neck is not compromised
when the expander is in-situ, urine does not gather for long
periods in the prostatic urethra thereby preventing encrustation of
the expander. In addition, the expender is configured such that
when deployed in-situ within the prostatic urethra and correctly
positioned, blocking of the verumontanum 315 (and subsequent sexual
dysfunction) is avoided. To this end, a proximal end of the
expander 300 includes a suitably shaped cut-out 316 which prevents
the sidewall of the expander 300 coming into contact with the
verumontanum 315. In this embodiment, the expander 300 is not
restricted to the undulating ring structure of previous
embodiments, but may comprise any form of body such as for example
the mesh-type bodies commonly employed in stents, or indeed any
other type of body that is capable of adjustment between a radially
contracted orientation suitable for delivery and a radially
expanded orientation capable of dilating the prostatic urethra
while allowing flow of urine.
[0177] Referring to FIG. 38, an expander of the invention is shown
deployed in the prostatic urethra of a patent with BPH, between the
bladder neck muscle and the external sphincter. This figure shows
how the device accommodates the verumontanum between two prongs of
the expander in the distal prostatic urethra, while the proximal
end of the device is configured such that one of the prongs pushes
the transition zone of the prostate gland away from the lumen of
the prostatic urethra.
EQUIVALENTS
[0178] The foregoing description details presently preferred
embodiments of the present invention. Numerous modifications and
variations in practice thereof are expected to occur to those
skilled in the art upon consideration of these descriptions. Those
modifications and variations are intended to be encompassed within
the claims appended hereto.
* * * * *