Stress urinary incontinence (SUI) afflicts large numbers of women. One cause of SUI is believed to be the weakening of pelvic support structures, such as the fascia of the urethral wall, due to changes resulting from childbirth, pregnancy, menopause, etc.
A wide range of treatments of SUI are available depending on the severity of the condition and on the likely causes. However each of these approaches has limitations. Behavioral approaches (e.g., controlling diet and weight, muscular exercises, etc.) are often recommended only for mild cases and medication alone is generally ineffective while invasive surgical procedures entail significant patient discomfort and risk of complications.
The present invention is directed to an energy delivery device comprising an elongated body sized and shaped for insertion into a body lumen via a naturally occurring body orifice and an acoustic energy element emitting energy around a circumference of a portion of the elongated body in combination with an electrical connection between the acoustic energy element and a power source to drive the acoustic energy element.
The present invention is further directed to a device for treating urinary incontinence, comprising an elongated body including a core portion having a diameter adapted to fit in the urethra and a hollow, substantially cylindrical crystal disposed on the core portion for generating acoustic energy in combination with a power source coupled to the crystal for activating the crystal.
The present invention may be further understood with reference to the following description and the appended drawings, wherein like elements are referred to with the same reference numerals. The present invention is related to medical devices used to access and treat tissue within a body lumen or cavity. In particular, the present invention relates to a system and method of treating tissue with acoustic energy to heat and shrink target tissue. Although the present invention is described in detail in regard to the treatment of Stress Urinary Incontinence, those skilled in the art will recognize that the device and method may be used in any number of procedures for heating and shrinking tissue and that the device and method are especially suited for use in endolumenal applications.
Less invasive endoscopic procedures have proven more effective in many cases than behavioral and medication based treatments. During these procedures, an endoscopic device is advanced to the tissues to be treated (e.g., muscles and ligaments supporting the bladder) through, for example, a body lumen accessed via a naturally occurring body orifice. The treatments are selected to enhance the ability of the target tissues to maintain the bladder in a desired position. For example, an endoscopic device may be inserted into the urethra to a desired position to treat a target portion of the urethral wall fascia.
In an exemplary embodiment of the invention, the target tissue is heated to denature collagen and shrink the tissue so that it draws the bladder to a desired position within the pelvis. Another possible response to this therapeutic heating is initiation of a fibroplastic response to stiffen the tissue structures, which may stabilize the area around the urethra. By properly selecting the location and amount of shrinking, it is possible to minimally invasively relieve the symptoms of even more advanced SUI.
According to exemplary embodiments of the present invention, a therapeutic device delivers acoustic energy inside a body cavity or lumen to heat target tissue below the surface tissues to a desired temperature. In one embodiment of the invention, a crystal generates acoustic energy and directs it radially outward toward the target tissue. The size and location of the region of tissue to be treated may be defined by selecting a length of the crystal, as well as by appropriately designing the crystal, as will be described in more detail below.
An acoustic energy or piezo-electric element 104 receives an electrical energy and generates the acoustic energy used by the device 100 to provide thermal therapy to the target tissue. The acoustic energy element, also often called crystal, 104 is preferably a ceramic, which is electro statically poled to acquire piezo-electric properties. The common ceramic composition, which is used for the high intensity ultrasound applications, is Lead Zirconate Titanate, PZT. Other, not as common ceramics are Lithium Niobate, Potassium Niobate and Lead Nickel Niobate. The element, or crystal, is shaped to direct energy substantially symmetrically radially outward from the surface of the device 100 so that tissue surrounding the acoustic energy element 104 in all directions receives a substantially equal amount of energy. In the embodiment shown in
According to the exemplary embodiment of the invention, the acoustic energy element 104 is connected to a power source 112 via, for example, an electrical connection 110. The power source 112 provides electric energy to the acoustic energy element 104, to generate acoustic energy to heat the target tissue to the target temperature to denature the collagen of this tissue in order to shrink and/or stiffen the target tissue to the desired level.
In a different embodiment according to the invention, the transfer of acoustic energy from the acoustic energy element 104 to the surrounding tissue is enhanced via an acoustic coupler 106 surrounding the acoustic energy element 104. The acoustic coupler 106 preferably includes a reservoir of fluid having properties enabling it to carry acoustic energy more efficiently than the air which would otherwise surround the acoustic energy element 104 within the core 102. In one embodiment, water is the fluid used as it carries sound energy more efficiently than air. In this embodiment, a substantially rigid outer shell 108 is disposed around the acoustic energy element 104, forming an annular gap between the core 102 and the outer shell 108. The gap may be filled with the acoustic coupler 106, as shown in
In a different embodiment according to the invention, the outer shell 108 is formed of a compliant material which conforms to a shape of an inner surface of the lumen within which it is inserted. For example, an inflatable element such as a balloon may be used to form the outer shell 108 to accommodate variations in shape and size of the lumens from patient to patient. When this inflatable element is deflated it results in a overall lower cross-sectional area of the tip to facilitate insertion into, and passage through a lumen. Those skilled in the art will understand that the more completely a space between the acoustic energy element 104 and the target tissue is filled with the acoustic coupler 106, the more efficient the acoustic coupling between the device 100 and the target tissue will be.
In some cases, an area of tissue that is not continuous is to be treated with the acoustic energy. It is preferred to avoid exposing non-targeted tissue to energy as energy applied to this non-targeted tissue is damaging to tissue while producing no therapeutic benefit and as this diverts energy from the targeted tissue. Accordingly, a device 200 according to a further embodiment of the invention employs a segmented acoustic energy element 203 with the segment s thereof being arranged with gaps therebetween. The gaps are located so that, when the device 200 is in a desired position adjacent to the target tissue, the gaps are adjacent to corresponding non-targeted portions of tissue while the segments of the acoustic energy element are located adjacent to targeted portions of tissue. As shown in
To carry out certain procedures, it may be beneficial to direct the energy of the acoustic energy element in a more controlled manner. For example, the acoustic energy element may be shaped to focus or to diffuse the acoustic energy generated therein, to achieve a particular therapeutic goal.
An outer surface 306 of the acoustic energy element 304 which according to this embodiment is a piezo-electric element is shaped to aim acoustic energy generated thereby. For example, the outer surface 306 may be convex, so that the sound energy from the acoustic energy element 304 is diffused outward from the energy delivery device 300. This design may be useful, for example, in applications where direct contact with the tissue to be treated is desired (possibly for treatment of BPH) and/or situations where a large portion of target tissue is to be heated, without accentuating the energy delivery to any one particular point. This allows a shorter length crystal to treat a larger area of tissue below the surface.
The exemplary embodiments of the present invention described above are directed primarily to an energy delivery device insertable in a patient's urethra to treat stress urinary incontinence. However, the same device may be used for other purposes as well, to carry out procedures that require the heating of selected regions of tissue near a body lumen or cavity. For example, the invention may be used to treat medical conditions such as fecal incontinence, prostate cancer, BPH and gastro-esophageal reflux disease (GERD). The ability of the devices according to the invention to heat targeted tissue may be advantageously used to shrink and otherwise cause a therapeutic effect to the targeted tissue.
The present invention was described with reference to specific exemplary embodiments. Those skilled in the art will understand that changes may be made in details, particularly in matters of shape, size, material and arrangement of parts. Accordingly, various modifications and changes may be made to the embodiments described herein. The specifications and drawings are, therefore, to be regarded in an illustrative rather than a restrictive sense.