Surgery: light – thermal – and electrical application – Light – thermal – and electrical application – Thermal applicators
Reexamination Certificate
2000-08-25
2003-03-18
Gibson, Roy D. (Department: 3739)
Surgery: light, thermal, and electrical application
Light, thermal, and electrical application
Thermal applicators
C606S033000
Reexamination Certificate
active
06535768
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to unique therapeutic instruments and techniques for delivering thermal energy to a target tissue volume or site in an interior of a patient's body in a “non-invasive” manner for medical purposes, such as selective cell damage, cell necrosis, molecular contraction or tissue stimulation. An exemplary embodiment of the invention is a catheter-like device with a working portion that can be introduced in a patient's urethra in a treatment for urinary incontinence. A treatment for gastro-esophageal reflux disease also may be fashioned to increase the rigidity or the length of the lower esophageal sphincter (LES) by laying down a fiber matrix around the LES. The device delivers thermal energy to “subsurface” or extraluminal tissues at a precise pre-selected “target” site, at the same time minimizing trauma to the wall around the lumen as well as tissues outward from the “target” site. The principal use of the exemplary embodiment is to selectively damage cells around a patient's sphincter which thereafter causes population of the extracellular compartment of the injury site with a collage fiber matrix. The collagen matrix serves as a means of altering cellular architecture and thus the bio-mechanical characteristics of the sphincter. The instrument of the invention also may be used to hydrothermally shrink such collagen fiber matrices in a periodic treatment cycle to further “model” target tissue flexibility to further alter the bio-mechanics of the sphincter.
SUMMARY OF THE INVENTION
The subjects and objects of this disclosure relate to novel techniques and instruments for the controlled modeling or remodeling of cellular architectures in the interior of a patient's body to alter the structural support of tissue layers, the support within anatomic structures such as organs or body conduits, or to alter the biomechanical characteristics of tissue masses or volumes in the interior of the body, including but not limited to soft tissues, organs and lumened structures (e.g., esophagus, urethra), such tissues hereafter referred to as a “target” tissue volume or mass.
In the prior art, site-specific thermal treatment of cellular tissues in the interior of a patient's body generally require direct contact of the targeted cellular tissues with a medical device such as an thermal electrode, usually by a surgical procedure that exposes both the targeted cellular tissue and intervening tissue to trauma. For example, various microwave, radiofrequency and light energy (laser) devices have been developed for intraluminal use to thermally treat intraluminal tissues as well as extraluminal tissue volumes to destroy malignant, benign and other types of cells and tissues in a wide variety of anatomic sites. Tissues treated include isolated carcinoma masses, and more specifically, organs such as the prostate. Such prior art devices typically include a catheter or cannula which is used to carry a radiofrequency electrode or microwave antenna through an anatomic duct or conduit to the region of treatment to apply energy directly through the conduit wall into the surrounding tissue in all directions. Severe trauma often is sustained by the duct wall during the thermal energy delivery to extraluminal target tissues. Some prior art devices combine cooling systems to reduce trauma to the conduit wall. Such cooling mechanisms complicate the device and require that the device be sufficiently large to accommodate this cooling system. Other prior art devices use catheters with penetrating elements that are extendable through the duct wall to access the target tissue mass, such as a device for treating benign prostatic hyperplasia.
More in particular, the present invention discloses “non-invasive” techniques and instruments that utilize thermal energy to selectively damage or injure certain cells in a site-specific volume in the interior of a body. By the term non-invasive, it is meant that the working end of the device does not penetrate the interior of the body through any incision in tissue. The non-invasive working end of the device still may be disposed in the interior of the body by passing through an orifice into a lumen or duct in a body-however, the device will not penetrate a wall of the orifice.
The non-invasive selective damage to cells in target tissues induces a biological response to the injury. Such a biological response includes cell reproduction or repopulation along with the proliferation of a fiber matrix of collagen in the extracellular space. Thus, the controlled modeling of the structural or mechanical characteristics of targeted tissue volume is possible by creation of such a collagen fiber matrix therein. Such selective injury to particular cell volume is accomplished by modifying the extracellular fluid content (ECF) so as to increase its resistance (R) to RF energy when compared to the surrounding tissue volume, thus causing site-specific thermal energy delivery to selectively injure a certain cell population.
Various terms may be suitable for describing either elements of the process of thermal modeling of tissue by altering the bio-mechanical characteristics of the targeted tissue volume with the creation of a collagen matrix in the extracellular space. Terms such as inducing connective tissue formation, aggregating fibrous tissue, inducing the formation of scar tissue, tissue massing or tissue bulking, fibrosis, fibrogenesis, fibrillogenesis, etc. have been used. Various other terms have been used to describe the thermal effects on collagen molecules or fibers in the interior of the body and deal with dimensional changes-such as tissue shrinkage, molecular (both intra- and intermolecular) shrinkage, cellular (both intra- and extracellular) shrinkage or contraction, contracture, etc. For clarity of presentation, this disclosure will use the terms “modeling” to describe an object of a treatment. Other various terms relating to the formation of a extracellular “collage matrix” or “matrices” having “fiber” characteristics will be used for the purpose of describing more specific objects of the invention. When referring to reducing dimensional changes in a tissue volume, whether at the cellular or intracellular level, the terms “shrinkage” or “contraction” will be used. These terms are thus inclusive of the aforementioned words, and all other phrases and similar terms that relate to biophysical phenomena of collagen matrix formation and tissue modeling described in more detail below. The above-described objects or the invention are accomplished by controlled manipulation of bio-physical actions or phenomena relating to (i) induction of the injury healing response within a tissue volume in the interior of a body to populate the volume with a collagen fiber matrix of in the extracellular space. The objects of the invention further include (ii) the selective hydrothermal shrinkage of collagen fibers in the target tissue volume of surrounding tissue volumes subsequent to, or during, the injury healing response.
As background, the injury healing response in a human body is complex and first involves an inflammatory response. A very mild injury will produce only the inflammatory reaction. More extensive tissue trauma—no matter whether mechanical, chemical or thermal—will induce the injury healing response and cause the release of intracellular compounds into the extracellular compartment at the injury site. This disclosure relates principally to induction of the injury healing process by thermal energy delivery; the temperature required to induce the process ranging from about 45° to 65° C. depending on the target tissue and the duration of exposure. Such a temperature herein is referred to as T
cd
(temperature level that causes “cell damage” to induce the injury healing response). It is important to note that the temperature necessary to cause cell damage may be substantially lower than the temperature (T
SC
) necessary to shrink collagen fibers described below.
In order to selectively damage cells to induce the populatio
Baker James A.
Shadduck John H.
Gibson Roy D.
Ryan Kromholz & Manion
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