Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
1997-02-10
2001-05-29
Seidel, Richard K. (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S265000, C604S048000, C604S104000, C604S517000, C606S192000
Reexamination Certificate
active
06238368
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to the treatment of a natural lumen or passage located in a filled area, in particular in a solid organ of the human or animal body, which lumen provides for the transit or circulation of a fluid, in particular a body fluid, which is either liquid or gaseous, this natural lumen or passage being obstructed by the effect of a local cell proliferation.
The urinary passages, and in particular the urethra, constitute examples of natural lumina within the meaning of the present invention.
The expression “local cell proliferation” is understood to mean any biological process, for example of the benign or malignant tumor type, leading locally to a tissue excess, either organized or unorganized, and provoking an obstruction, or obstructing the natural lumen or passage in question, at the site where said proliferation develops. Benign prostatic hypertrophy, or prostatic adenoma, constitutes one example of an obstructive cell proliferation of this nature.
The present invention will be introduced, defined and described, by way of non-limiting example, with reference to the treatment of acute or chronic prostate obstructions in man.
DESCRIPTION OF THE PRIOR ART
It is presently known to treat prostate obstruction by mechanical means, that is to say without curative action vis-à-vis the cause of the obstruction, and for this purpose various intraurethral prostheses have been described or are available on the market. Reference will be made, by way of example, to the prosthesis which is described in document WO-A-94/18907.
Such prostheses, which are implanted permanently or temporarily, provide for only a palliative treatment of the prostate obstructions.
These prostheses may be poorly tolerated by the patient on account of their purely mechanical action, these prostheses being foreign bodies which are left in place permanently, or else temporarily but repeatedly. In some cases there may be a risk of infection and of not inconsiderable migration. These prostheses, when they are permanent, present a risk of obstruction, either by incrustation (deposition of crystals contained in the urine) or by hyperplasia inside the prosthesis, as a reaction to the foreign body which the prosthesis represents; this hyperplasia can go so far as to obstruct certain permanent prostheses.
SUMMARY OF THE INVENTION
The object of the present invention is to remedy these disadvantages.
More specifically, the invention relates to a treatment, of an obstruction in a natural lumen, which is limited in time, is of the curative type, and has a local and selective action.
In accordance with the present invention, a novel therapeutic treatment device is proposed which can be implanted in the natural lumen or passage to be treated and which comprises:
in a manner known per se, a non-biodegradable tubular element which is designed to be placed and retained, in a substantially self-stabilizing manner, in the natural lumen being treated; this element, which is preferably of cylindrical shape, is at one and the same time sufficiently flexible to conform to the natural lumen lying against its wall, and sufficiently rigid to maintain an artificial channel, and hence a circulation, in the natural lumen;
in a novel manner, a medicinal sleeve which is supported by the tubular element and which is positioned along the length of, and around, the latter, so as to come into line with, and into direct contact with, the obstruction once the natural lumen has been intubated with said tubular element; this sleeve comprises or incorporates a therapeutic agent which is cytoreductive, in particular cytotoxic, specifically vis-à-vis the cells of said local cell proliferation, essentially through simple, superficial and solid tissue contact with said cells; this sleeve is moreover designed to deliver this therapeutic agent at least in its outer portion.
According to the present invention, the expression “supported by” is understood to mean that the medicinal sleeve is present on the tubular element, either visibly and/or distinct from the latter, or such that it cannot be seen, being held or incorporated in said tubular element, in its material or its constituent elements, over a length and/or at a position which are predetermined by said tubular element.
According to the present invention, the term “therapeutic” is understood to mean any treatment of a medicinal and in particular chemical type, in isolation, or complementing another treatment, and permitting local and selective reduction of the obstruction of the natural lumen or passage in question, whether it be the cells lining the wall of said lumen, or the cells situated deep behind these cells. According to the present invention, this treatment of the medicinal type is facilitated or supplemented by a treatment of the mechanical type, the aim being to maintain during treatment, and then to reestablish, the flow in the natural lumen which is disrupted or prevented as a result of the obstruction of this same lumen.
By virtue of the invention, once the therapeutic device has been arranged in the obstructed natural lumen, the medicinal sleeve selectively delivers the cytoreductive agent to the obstructed part of the wall of the natural lumen, and then to the subjacent cell proliferation. As a consequence of this delivery, there is a gradual erosion of the obstructed part of the wall of the natural lumen being treated, then of the subjacent tissue responsible for the compression or obstruction of this same lumen, along a front which has the shape of a cylindrical envelope, progressing radially outward, in a manner substantially concentric with the medicinal sleeve. This thus leads to the formation of a channel through the lumen being treated, which channel has a transverse dimension at least greater than the normal transverse dimension of the same lumen. As soon as the contact between the outer surface portion of the medicinal sleeve and the surrounding tissues or cells ceases, the cytoreductive action ceases, it being understood that the latter action can also cease by means of the therapeutic device according to the invention simply being withdrawn from the natural lumen in which it has been positioned.
All in all, this leads to a pharmaceutically induced modeling of the natural lumen being treated, leaving behind a channel which has as it were been “molded” on the tubular element of the therapeutic device according to the invention.
Consequently, as a result of a dual action—both medicinal and mechanical—of the device according to the invention, it is thus possible to construct a new channel in the obstructed part of any natural lumen, this channel having substantially the same axis and the same shape as the tubular element which has been used to shape it. Once this new channel has been created, the device according to the invention is withdrawn, and the new duct thus obtained acquires an epithelium from the upstream and downstream parts of the natural lumen not being treated with the medicinal sleeve.
Although the following is one embodiment of the invention among others, it is preferable, on the one hand, for the tubular element to comprise an internal core, which is cylindrical for example, and made of a biocompatible material, in particular a relatively smooth and soft material, for example silicone rubber, and, on the other hand, for the medicinal sleeve, distinct from the tubular element and covering the latter, to be arranged outside the core, and to comprise a biologically compatible substrate or support which incorporates the cytoreductive therapeutic agent.
A therapeutic device according to the invention also affords the following important advantages.
The cytoreductive therapeutic agent is delivered in situ, and specifically to the cell proliferation generating or having generated the obstruction in the natural lumen. Such a local administration of a cytoreductive active principle considerably reduces the side effects or morbidity compared to administration of the same active principle systemically, for example by the oral
Oliff & Berridg,e PLC
Rodriguez Cris
Seidel Richard K.
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