Surgery – Instruments – Light application
Reexamination Certificate
1999-07-14
2002-07-23
Dvorak, Linda C. M. (Department: 3739)
Surgery
Instruments
Light application
C606S003000, C606S007000, C607S088000, C607S089000, C128S898000
Reexamination Certificate
active
06423055
ABSTRACT:
FIELD OF THE INVENTION
The technical field of this invention is phototherapy and, in particular, methods and devices which employ optical fibers and flexible light-waveguides to deliver radiation to a targeted site.
BACKGROUND OF THE INVENTION
Destruction of cellular tissues in situ has been used in the treatment of diseases and medical conditions alone or as an adjunct to surgical removal procedures. These methods are often less traumatic than surgical procedures and may be the only alternative where surgical procedures are unfeasible. Phototherapeutic treatment devices, e.g., lasers, have the advantage of using intense light energy which is rapidly attenuated to a non-destructive level outside of the target region. However, blood and/or other body fluids greatly diminish the effectiveness of several of these light energy sources as the radiation passes from an energy source, e.g., a laser source, through the body fluid to a treatment site. For example, the energy can be scattered or be absorbed by blood and other body fluids between the energy source and the tissue treatment site.
A common medical application of lasers is in the irradiation of tissue, both internal and external. For external treatment, the laser energy can be applied directly. However, where a procedure requires irradiation of internal tissues that are not readily accessible to external energy sources, the use of catheter-type devices to deliver coherent radiation to the treatment site is common. Typical applications requiring use of laser catheters are found in the treatment of various anatomical structures and conditions within the cardiovascular system.
Microwave, radio frequency, and acoustical (ultrasound) devices as well tissue destructive substances have also been used to destroy malignant, benign and other types of aberrant cells in tissues from a wide variety of anatomical sites and organs. Tissues sought to be treated include isolated carcinoma masses and, more specifically, organs such as the prostate, bronchial passage ways, passage ways to the bladder, passage ways to the urethra, and various passage ways into the thoracic area, e.g., the heart.
Devices useful for the treatment of such disease states or conditions typically include a catheter or an cannula which can be used to carry an energy source or waveguide through a lumen to the zone of treatment. The energy is then emitted from the catheter into the surrounding tissue thereby destroying the diseased tissue, and sometimes surrounding tissue.
Catheters have been utilized in the medical industry for many years. One of the greatest challenges in using a catheter is controlling the position and placement of the distal portion of the catheter from a remote location outside of the subject's body. Some catheters have features designed to aid in steering the catheter and overcoming this challenge. However, several significant problems are still encountered with catheters.
Careful and precise control over the catheter is required during critical procedures which ablate tissue within the heart. Such procedures are termed “electrophysiological” therapy and are becoming widespread for treatment of cardiac rhythm disturbances. During these procedures, an operator guides a catheter through a main artery or vein into the interior of the heart which is to be treated. The operator manipulates a mechanism to cause an electrode which is carried on the distal tip of the catheter into direct contact with the tissue area to be treated. Energy is applied from the electrode into the tissue and through an indifferent electrode (in a uni-polar electrode system) or to an adjacent electrode (in a bi-polar electrode system) to ablate the tissue and form a lesion. The irradiation of tissue must be accomplished with great precision as the danger of also damaging other adjacent tissue is always present, especially when the process occurs remotely at the distal end of a relatively long catheter.
One partial solution to this problem has been to “map” the area to be treated prior to a procedure. Cardiac mapping can be used prior to ablation to locate aberrant conductive pathways within the heart. The aberrant conductive pathways are called arrhythmias. Mapping of the heart identifies regions along these pathways, termed “foci”, which are then ablated to treat the arrhythmias.
During laser ablation procedures, a catheter serves to deliver a fiber optic wave guide to the target region. Radiation transmitted through the optical fiber essentially vaporizes the targeted tissue to achieve the desired therapeutic goals of the procedure. Complete destruction of target tissue, with the exception of certain narrow and specific cardiac treatments, is generally limited to cardiological applications, e.g., removal of a blockage. In electrophysiological treatments, total destruction of target tissue (ablation) is not necessary, but controlled denaturation of tissue to affect its electrophysiological properties is required.
Within the heart, variations in cardiac tissue characteristics, perhaps as the result of scarring from previous cardiac trauma, can present vastly different tissue that react differently to the laser energy source. For example, absorption characteristics of normal tissue can be much different from tissue that is heavily scarred. In addition, the trabecular nature of the endocardium increases the difficulty because the laser radiation must reach a highly contoured or folded target tissue surface. As a result, temperatures of the tissue surface where the laser energy is incident can be much higher for some tissue than for others. In the treatment of cardiac tissue, the dynamic state of the heart tissue further complicates the situation in that the heart is constantly moving during treatment. Thus, incorporation of fixation means to maintain the position of the distal end of the laser catheter with respect to the target tissue site is often required.
There are drawbacks with many of the currently available catheters and treatments. Oftentimes it is difficult, if not impossible, to maneuver the instrument into small passage ways, such as a ventricle, without damaging the surrounding tissue. Most therapeutic treatments require that the apparatus is in contact with the tissue and with blood and/or other body fluids. Additionally, focusing the ablative energy onto the tissue site to be treated can be problematic, especially when vital organs surround the diseased tissue. Therefore, it would be desirable to focus ablative energy onto a specific treatment area wherein surrounding tissue is not degraded, the energy source is not in direct contact with the tissue and blood and body fluids are not coagulated or destroyed.
SUMMARY OF THE INVENTION
The present invention circumvents the problems described above by delivering energy, e.g., laser light or other ablative energy, in an annular pattern without requiring direct contact with an energy source, e.g. a laser (via fiber), with the targeted tissue. This indirect contact with the targeted tissue provides an advantage that damage to surrounding tissues is minimized or eliminated. More specifically, in cardiac therapy, another advantage is that an annular conduction block is created about the pulmonary vein orifice, thereby eliminating aberrant wave conduction.
In one embodiment, the present invention includes an apparatus for inducing phototherapeutic processes in tissue which can include ablation and/or coagulation of the tissue. Typically the optical apparatus is contained within a catheter including a flexible elongate member having a proximal end, a distal end and a longitudinal first lumen extending therebetween. The distal end of the flexible elongate member is open or includes a transparent cap, a centering balloon, or a centering coil. The optical apparatus of the invention can be slidably extended within the first lumen for projecting light through or from the distal end of the flexible member. Alternatively, the optical fiber and other light projecting elements can be fixed in place with the catheter.
The optical a
Farr Norman E.
Wieler William E.
CardioFocus, Inc.
Dvorak Linda C. M.
Engellenner Thomas J.
Farah Ahmed
Nguyen Tram Anh T.
LandOfFree
Phototherapeutic wave guide apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Phototherapeutic wave guide apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Phototherapeutic wave guide apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2862435