Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
2002-05-01
2004-09-28
Casler, Brian L. (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S265000, C606S027000, C607S113000
Reexamination Certificate
active
06796960
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to medical devices and, more particularly, to medical devices configured for insertion into a lumen or cavity of a subject.
RESERVATION OF COPYRIGHT
A portion of the disclosure of this patent document contains material to which a claim of copyright protection is made. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but reserves all other rights whatsoever.
BACKGROUND OF THE INVENTION
Several types of thermal treatment systems are known for treating certain pathologic conditions of the body by heating or thermally ablating targeted tissue. These thermal treatment systems have used various heating sources to generate the heat necessary to treat or ablate the targeted tissue. For example, laser, microwave, and radio-frequency (RF) energy sources have been proposed to produce heat, which is then directed to the targeted tissue in or around a selected body cavity. Thermal treatment systems have been used to thermally ablate prostatic tissue, as well as tissue of different organs. The term “thermal ablation” refers to exposing targeted tissue to a temperature that is sufficient to kill the tissue.
One particularly successful thermal ablation system is designed to thermally ablate prostatic tissue by a thermocoagulation process. In males, the prostate gland can enlarge and the prostatic tissue can increase in density resulting, unfortunately, in the closing off of the urinary drainage path. This condition typically occurs in men as they age due to the physiological changes of the prostatic tissue (and bladder muscles) over time.
To enlarge the opening in the prostatic urethra (without requiring surgical incision and removal of tissue), a conventional thermal ablation system employs a closed loop liquid or water-induced thermotherapy (WIT) system which heats liquid, typically water, external to the body and then directs the circulating heated water into a treatment catheter, which is inserted through the penile meatus and held in position in the subject undergoing treatment to expose localized tissue to ablation temperatures. The treatment catheter typically includes an upper end portion, which, in operation, is anchored against the bladder neck, and an inflatable treatment segment that is held, relative to the anchored upper end portion, such that it resides along the desired treatment region of the prostate.
In operation, the treatment segment expands, in response to the captured circulating fluid traveling therethrough, to press against the targeted tissue in the prostate and to expose the tissue to increased temperatures associated with the circulating liquid, thereby thermally ablating the localized tissue at the treatment site. The circulating water is typically heated to a temperature of about 60-62° C. and the targeted tissue is thermally treated for a period of about 45 minutes to locally kill the tissue proximate the urinary drainage passage in the prostate and thereby enlarge the urinary passage through the prostate.
Referring to
FIG. 1
, the anatomy of the male urethra
5
, showing a thermal ablation treatment region
10
in the prostate
11
, is illustrated. The thermal ablation treatment region
10
is indicated by the lined region in the prostate
11
. For thermal ablation therapy, the treatment can be targeted to be carried out in a localized treatment region called the prostatic urethra
6
, the treatment region
10
being generally described as the upper portion of the urethra from the prostate, which extends generally below the bladder neck
12
a
and above the verumontanum
11
b
of the subject. Alternatively, the treatment region
10
may include the bladder neck
12
a
or a portion of the bladder neck
12
a
itself.
FIG. 2A
illustrates a treatment catheter
20
used in a WIT prostate treatment system identified as the Thermoflex® System available from ArgoMed Inc. of Cary, N.C. As shown, the treatment catheter
20
includes a bladder-anchoring balloon
22
, a treatment balloon
23
, and an elongated shaft
25
. The catheter
20
is flexibly configured so as to be able to bend and flex to follow the shape of the lumen (even those with curvatures as shown in
FIG. 2A
) as it is introduced into the lumen until the distal portion of the catheter
20
reaches the desired treatment site. The catheter
20
is sized as an elongated tubular body with a relatively small cross-sectional area having a thin outer wall so as to be able to be inserted into and extend along a length of the desired lumen to reach the desired treatment site.
As shown in
FIGS. 2B and 2C
, the catheter
20
includes inlet and outlet fluid circulating paths
26
i
,
26
o
, respectively, as well as a urinary drainage channel
28
(which can also be used to deliver medicaments therethrough while the catheter
20
is in position in the subject). In operation, heated fluid or liquid, such as water or a water-based liquid, is heated external of the subject, directed into the catheter
20
, and circulated in the enclosed fluid paths
26
i
,
26
o
in the catheter
20
. The fluid is directed such that it travels through the catheter via the inlet path
26
i
to the treatment balloon
23
located proximate the desired treatment site and then back out of the treatment balloon
23
to the outlet path
26
o
, and then out of the subject. As shown in
FIG. 2C
, the circulating fluid is directed into the treatment balloon
23
which then expands in response to the quantity of fluid residing or traveling therein.
In operation, in order to anchor the catheter
20
in a desired position or location within the prostate
11
(after the catheter
20
is inserted into the prostate
11
) through the urethra
5
, the anchoring balloon
22
is inflated via a fluid (or other inflation media) introduced through the shaft
25
to the distal portion of the catheter
20
to cause the anchoring balloon
22
to take on an expanded configuration and reside against the bladder neck
12
a
of the subject (FIG.
1
). Thus, when expanded, the anchoring balloon
22
is adapted to position the treatment balloon
23
in the prostate relative to the bladder
12
. When deflated, the catheter
20
, including the anchoring and treatment balloons
22
,
23
, can be removed from the urethra
5
of the subject.
For ease of insertion within and removal from a subject, it is desirable that catheters used for thermal ablation, particularly the anchoring and treatment balloons of such catheters, have a low, smooth, substantially constant profile during insertion and removal. Unfortunately, conventional anchoring and treatment balloons, when deflated, may not have a low profile and may have an irregular, non-smooth profile configuration. This may be particularly problematic in those balloons that are formed to take on a predetermined radial inflated shape, which they can retain even when asymmetrically compressed or pinched, in a manner that exposes a portion of the balloon to increased pressures. Exemplary anchoring and treatment balloons
22
,
23
of a catheter
20
used for thermal ablation of prostatic tissue are illustrated in
FIG. 3
in respective deflated configurations. The illustrated anchoring balloon
22
has plurality of “wings”
30
when deflated so as to provide sufficient material that creates an effective anchoring structure when the anchoring balloon
22
is inflated.
Unfortunately, the wings
30
of the anchoring balloon
22
may cause discomfort and/or irritation to a subject when inserted through a lumen or other body cavity, such as the male urethra. In addition, the treatment balloon
23
, when deflated, has a diameter that is larger than the catheter shaft
25
. The size of the treatment balloon
23
may also cause discomfort and/or irritation to a subject when inserted through a lumen or other body cavity, such as the male urethra.
SUMMARY OF THE INVENTION
In view of the above discussion, catheters and stents
Cioanta Iulian
Lazarovitz Jacob
Casler Brian L.
Ganz Bradley M.
Ganz Law PC
Han Mark K.
WIT IP Corporation
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