Patent Publication Number: US-2021169563-A1

Title: Fractional treatment of urinary incontinence

Description:
FIELD OF THE INVENTION 
     The invention relates to a method for fractional treatment of urinary incontinence using radio-frequency (RF) energy delivered through an array of needles. 
     BACKGROUND OF THE INVENTION 
     There are many surgical and non-surgical methods for treatment of severe urinary incontinence ( SUI ) using RF energy. The methods include remodeling of collagenous tissue applying RF energy through a device inserted into the vagina and creating heat to contract the collagenous support tissue. 
     Some prior art methods create shrinkage of tissue around the bladder neck or urethra. The inventions describe delivering RF energy through the vaginal, urethral or bladder wall. 
     SUMMARY OF THE INVENTION 
     The present invention provides a method for fractional treatment of vaginal tissue around the urethra to contract the collagen and/or scar the tissue for better support of the urethral channel. The method includes positioning the device to create fractional lesions at a safe distance from the urethra and vagina. The invention describes a method of treatment of peri-urethral tissue using multiple needles inserted at the introitus into the urethra; the needles are fixed with a member inserted into the urethra. 
     The device is based on a minimally invasive procedure where at least two needle electrodes are inserted in soft tissue close to the urethra. The size of the electrode is designed to create a higher energy density in the vicinity of the electrode. The RF energy density is high enough to create a contractive tissue change around the electrode. The device has a rigid position fixator designed to be inserted into the urethra and a mechanism for aligning the needle electrodes to be substantially parallel to the urethra so the needles enter the tissue at a predetermined distance from the urethra canal. The purpose of the aligning mechanism is to position the needle electrodes around the urethra to avoid mechanical or thermal damage to the urethra, vagina or bladder wall. 
     In one embodiment the distance between the urethral position fixator and needle electrodes is fixed. The needle electrode may fill the volume around the urethra to create a stronger thermal effect. 
     Alternatively, the distance between the needle electrodes and the urethral position fixator can be selected according to the individual anatomy of the patient. 
     The position fixator may have a smooth surface and a blunt end to avoid mechanical damage of the urethra. Lubrication can be used for easy insertion. 
     The needle electrodes may be inserted into the tissue to a depth from 3 mm up to 20 mm to provide enough collagen contraction to support the urethra. The active electrode may be rigid enough to avoid undesired bending in the tissue. 
     The needle electrodes may have an insulated area and a conductive area at the distal end of the electrode. The needle electrodes may have multiple conductive and insulated areas to provide an optimal treatment thermal profile in the tissue. An insulating coating can be used to minimize damage of tissue surface and reduce healing time. Alternatively, the needle electrode may not have an insulating coating. 
     The needle electrodes may have an embedded temperature sensor to control tissue heating up to the temperature providing collagen contraction. Typically, heating temperature is varied from 45° C. up to 100° C. Temperature can be above 100° C. causing evaporation or carbonization of tissue at high peak RF power. The tissue heating may result in tissue coagulation, tissue ablation, tissue contraction, tissue scarring. 
     The needle electrode may be inserted manually or by using an electro-mechanical system. Insertion depth can be controlled by the device according to a predetermined setting. 
     Alternatively, insertion depth can be controlled manually by the user according to depth marks on the device. 
     The RF energy can be applied to all needles simultaneously or controlled individually for each needle. Energy delivery to the needles can be controlled according to treatment feedback, which can be one or more feedbacks from tissue temperature measurements, tissue impedance or needle position. 
     The RF energy can be applied between pairs of needles, between groups of needles or between one needle and other needle electrodes acting as a return electrode. 
     Alternatively, a return electrode can be applied to the tissue surface in the vicinity of the treatment area or to another body part. 
     The large area fixator inserted into the urethra can serve as a return electrode. 
     The return electrode should have a substantially larger conductive area than the active electrode to avoid tissue thermal damage in the area coupled to the external electrode. The return electrode can be structured from one or more conductive elements. The return electrode may have an embedded thermal sensor to avoid tissue overheating. 
     The part of the electrodes coming in contact with the tissue may be made from biocompatible materials. For example, the internal electrode tip may be made from stainless steel or titanium. RF electrodes may have a thin dielectric coating providing capacitive electrical coupling for delivering RF energy. 
     A motor or solenoid can be used for insertion of the needles into the tissue. Step or DC motor can be used to push the needle electrodes to the predetermined depth. Operation of the motor can be controlled by the controller. 
     The parameters of the RF energy may be adjusted for tissue contraction. RF energy can be delivered in pulsed or continuous mode. Frequency of RF current may be varied from 200 KHz up to 40 MHz. The most optimal range of RF frequencies used for fractional tissue coagulation is from 400 kHz up to 6 MHz. In order to improve electrical coupling, a conductive solution can be applied to the return electrode. Conductive liquid or gel can be used to hydrate tissue under the return electrode and improve electrical contact. RF energy can be controlled by the controlling of RF power or RF pulse duration. Another option to control average RF power is by delivering constant RF power with a train of shorter pulses and controlling the duty cycle of the RF pulses. 
     In order to reduce pain and improve tissue conductivity, anesthesia can be applied to the treated tissue prior to the procedure. 
     Controlling the distance between the active electrode, urethral fixator and return electrode placed in the vagina enables optimizing the safe position of the RF electrode between the urethra and vagina. The distance can be controlled by selection of a treatment tip with a predetermined distance from the fixator to the needles. Alternatively, the fixator position can be adjustable in the same tip to change the distance between the needles and fixator. 
     In some embodiments the device may have a circuit that measures tissue impedance. Any change in the measured impedance between the electrodes may provide information about the distance between the electrodes. Measuring the tissue impedance also provides information about tissue heating and quality of electrical contact between the return electrode and tissue surface. An electronic circuit may measure RF current, voltage, impedance or other RF parameters. 
     Cooling of the return electrode and or urethral fixator may reduce risks of side effects. 
     The system for powering and controlling RF energy delivery may include a power supply that converts AC voltage from the wall plug to stabilized DC voltage. An RF generator may be connected to the power supply and generate high frequency voltage. The RF generator may be designed to maintain constant power in the working range of parameters. The system may have a controller that controls the RF parameters and a user interface includes an LCD screen and touch panel. The controller may have a microprocessor and dedicated software. The monitoring system measures RF parameters including tissue impedance and/or RF current and/or RF voltage or other electronic parameters. The system has one or more connectors to connect one or more electrodes to the system unit. 
     Thus, in one aspect, the invention provides a method for contracting supporting tissue between urethra and vagina by:
         Inserting a position fixator into the urethra to fix the urethra position.   Aligning multiple needle electrodes into the tissue around the urethra.   Applying RF energy between the needle electrodes to heat tissue in the vicinity of the conductive area of the needle electrodes.   Stopping RF energy delivery when a predetermined amount of energy is reached.   Extracting the needle electrodes out of the tissue.   Optionally, rotating the hand piece around the urethra fixator to insert the needle electrodes to the adjacent area.       

     In another aspect, the invention provides a method for contracting supporting tissue around urethra by:
         Inserting position fixator into the urethra to fix the urethra position.   Aligning multiple needle electrodes into the tissue around the urethra.   Applying RF energy between the needle electrodes and the return electrode placed on the tissue surface.   Stopping RF energy delivery when a predetermined amount of energy is reached.   Extracting the needle electrodes out of the tissue.   Optionally, rotating the hand piece around the urethra fixator to insert the needle electrodes to the adjacent area.       

     Other types of energy include focused ultrasound or laser radiation; they can be used to create fractional lesion around the urethra for treatment of urinary incontinence. Laser energy can be delivered to the tissue surface non-invasively or through the optical fibers inserted into the tissue in the vicinity of the urethra. Focused ultrasound can be used for creating lesions inside the tissue at variable depths. Mechanical multiple small lesions can be created to initiate tissue micro-scarring for better urethral support. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to understand the invention and to see how it may be carried out in practice, a preferred embodiment will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: 
         FIG. 1  shows a hand piece design; 
         FIG. 2  shows hand piece tips with needle electrodes, return electrode and urethra fixator; 
         FIG. 3  shows hand piece tips without return electrode; 
         FIG. 4  shows the hand piece tip applied to the urethral tissue; 
         FIG. 5 a    shows the needle electrode. 
         FIG. 5 b    shows a partially isolated needle electrode. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a hand piece  11  having a handle  13  and a disposable tip  12  used for applying RF energy to the patient. 
       FIG. 2  shows the disposable tip  12  wherein a urethra fixator  21  has a diameter of 3-6 mm. Needle electrodes  22  surround fixator  21  at a distance. This enables creating a thermal lesion around the needles without risk of urethra damage. RF energy is applied between the needle electrodes  22  and return electrode  23  is applied to the tissue surface. The needle electrodes  22  are pushed out of the tip when the user activates the pulse. When the needle electrodes  22  are moved out to a predetermined depth, the pulse of RF energy is applied between the needle electrodes  22  and return electrode  23 . Because the conductive area of needle electrodes  22  is smaller than the area of return electrode  23 , the thermal effect is stronger around the needles  22 . 
       FIG. 3  shows alternative tips  33  design without an external electrode. The RF energy is applied between one of the needle electrodes  22  acting as an active electrode and other needle electrodes acting as a return electrode. Then RF energy can be switched to connect another needle as the active electrode. Energy is switched between needle electrodes to create a thermal lesion in the vicinity of each lesion. 
     Alternatively, urethra fixator  31  can be made from a conductive material and act as an return electrode. RF energy is applied between needle electrodes  22  and urethral fixator  31 . 
       FIG. 4  demonstrates schematically a disposable tip  40  applied to the tissue. The urethral fixator  41  is inserted into the urethra  44 . Needle electrodes  42  are inserted into the tissue around the urethra  44 . Depth of needle electrode insertion is limited to avoid damage of the bladder  45 . Typically, insertion depth should not exceed 25 mm. RF energy is applied to the needle electrodes  42  to create thermal lesions  43  in vicinity of the needle electrodes. The size of lesions  43  should be small enough to avoid damage of urethra  44 . Size of the thermal lesions  43  is controlled by an amount of RF energy applied to the needle electrodes  42  and by duration of RF pulses. 
     The needle electrodes can be made from conductive materials as shown in  FIG. 5 a    to apply RF energy along the entire length of the needle electrode  52  and the sharp end of needle electrode  51 . 
     In order to minimize damage near the tissue surface, the electrode can be partially coated by an insulating material as shown in  FIG. 5 b   . Sharp end  51  and uncoated shaft  52  at the distal end of the needle electrode are uncoated to deliver RF energy. The proximal part  53  of the needle electrode is coated with a thin layer of insulating material to prevent RF energy delivery and minimize damage near the tissue surface. 
     The method of treatment includes the following steps:
         Inserting the fixator  41  into the urethra  43 .   Pushing needle electrodes  42  out of the tip into the tissue to predetermined depth.   Applying predetermined amount of RF energy to the needle electrodes  42  to create thermal lesions  43  in vicinity of needle electrodes  42 .   Retracting the needle electrodes  42  out of the tissue.       

     Using the method of the invention to treat urethra supporting tissue, the following exemplary parameter values of RF energy may be used:
         RF frequency: 0.2-40 MHz.   Average output RF power: from about 0.5 to about 500 W.   RF energy delivered during a time of 1 millisecond to 3 seconds.