Surgery: light – thermal – and electrical application – Light – thermal – and electrical application – Thermal applicators
Reexamination Certificate
2001-11-13
2004-07-06
Casler, Brian L. (Department: 3763)
Surgery: light, thermal, and electrical application
Light, thermal, and electrical application
Thermal applicators
C607S113000, C607S099000, C606S027000, C606S192000, C604S113000, C604S043000, C604S919000, C604S101010, C604S523000, C604S544000
Reexamination Certificate
active
06758857
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to catheters configured for insertion into a lumen or body cavity of a subject and is particularly suitable for insertion into the male urethra.
BACKGROUND OF THE INVENTION
Conventionally, several types of thermal treatment systems have been proposed to treat 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 the heat which is then directed to the targeted tissue in or around the selected body cavity. Thermal treatment systems have been used to thermally ablate prostatic tissue as well as to thermally treat or ablate the tissue of other organs, body cavities, and/or natural lumens.
One particularly successful thermal ablation system ablates the prostate by a thermocoagulation process. This 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. The treatment catheter is inserted through the penile meatus and held in position in the subject prior to initiation of the treatment to expose localized tissue in the prostate to ablation temperatures. The treatment catheter includes an upper end portion which, in operation, is anchored against the bladder neck and an inflatable treatment segment which 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. In addition, the pressurized contact can reduce the heat sink effect attributed to blood circulation in the body, thus enhancing the depth penetration of the heat transmitted by the inflatable treatment segment into the prostatic tissue.
As an acceptable alternative to surgery (transurethral resection of the prostate (TURP)), the use of WIT (water-induced thermotherapy) has been shown to be a successful and generally minimally invasive treatment of BPH (benign prostatic hyperplasia). Generally stated, the term “BPH” refers to a condition wherein the prostate gland enlarges and the prostatic tissue increases in density which can, unfortunately, tend to close off 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 prostate urethra (without requiring surgical incision and removal of tissue), the circulating hot water is directed through the treatment catheter which is inserted into the penile meatus up through the penile urethra and into the prostate as described above. The treatment segment expands with the hot water held therein to press the inflated treatment segment against the prostate, which then conductively heats and thermally ablates the prostatic tissue. 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.
Subsequent to the delivery of the thermal ablation (or other) treatment, the treated tissue in the prostate undergoes a healing process. Initially, the ablated tissue can expand or swell due to inflammation or edema which can undesirably block or obstruct the prostatic urethra. Further, during the healing period, portions of the treated tissue can slough off and create an undesirable and unduly limited opening size. This post-ablation or post-therapy treatment opening size can be positively influenced by “molding” the treated or ablated tissue during the healing cycle to contour the tissue about a catheter or stent held thereat. Therefore, to facilitate proper healing and to enhance the efficacy of the therapy and particularly, ablation therapy, either the treatment catheter is left in the subject for a period of time and/or a post treatment catheter, such as a conventional Foley catheter, is positioned in the subject. Conventionally, the treatment catheter can be left in the subject for about 24-72 hours after delivering the thermal treatment to the targeted tissue to reduce the likelihood that the treatment site will be injured by premature removal of the treatment catheter.
The treatment catheter typically includes insulated regions on the proximal shaft portion of the catheter to protect non-targeted tissue from undue exposure to heat as the heated fluid travels in the catheter fluid circulation passages to the desired treatment region. The insulated regions have, in the past, been provided by configuring the catheter with an extra layer or thickness of a material along the proximal or lower shaft portion. Other treatment catheters include a series of circumferentially arranged elongated air channels or conduits which encircle the heated circulating fluid passages and provide thermal insulation along the elongated shaft portion of the catheter as described in U.S. Pat. Nos. 5,257,977 and 5,549,559 to Eshel, the contents of which are hereby incorporated by reference as if recited in full herein. As the heated fluid travels through the fluid circulating passages, the insulation reduces the heat transferred to non-targeted treatment sites, such as along the penile meatus, urethral mucosa, or urethral sphincter for the BPH application. There remains a need, nonetheless, to provide improved thermal insulation for the heated circulating fluid.
In addition, the treatment catheter is typically a relatively small, thin-walled conformable or flexible catheter that is sized to be inserted into the body lumen and which usually includes a urine drainage lumen extending through the catheter. However, the catheter can deform due to exposure to the treatment temperatures over the treatment period. This deformation can, unfortunately, partially collapse the drainage lumen and, thus, reduce the urine drainage volume capacity of the treatment catheter.
Objects and Summary of the Invention
It is therefore an object of the present invention to provide economical treatment catheters with improved thermal insulation regions.
It is another object of the present invention to provide catheters with enhanced thermal transfer or thermal transmissivity configurations in the treatment balloon region.
It is another object of the present invention to provide a device which can inhibit obstruction in a fluid path (such as to keep a urinary drainage path open), during and/or post-treatment with improved fluid flow volumes such that the subject is able to receive and/or discharge fluid at desired flow rates.
It is another object of the present invention to provide treatment catheters with increased drainage volume after exposure to elevated treatment temperatures.
It is an additional object of the present invention to provide methods for producing improved catheters with insulation and/or improved urinary drainage volumes.
It is yet another object of the present invention to provide methods for thermally treating a body lumen in a manner which inhibits the exposure of non-targeted tissue to excessive heat while allowing sufficient flow volume therethrough.
These and other objects are satisfied by the present invention, which provides, inter alia, flexible catheters with improved thermal insulation and/or improved drainage lumen configurations and related methods of forming same. The present invention can also provide methods of thermally treating a body lumen and methods of fabricat
Cioanta Iulian
Klein Richard Barry
Lazarovitz Jacob
Acmi Corporation
Casler Brian L.
Ganz Law P.C.
Ganz, Esq. Bradley M.
Rodriguez Cris
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