Patent Publication Number: US-2021161591-A1

Title: Rf fractional device for treatment at different tissue depths

Description:
CROSS-REFERENCE TO OTHER APPLICATIONS 
     This application claims priority from, and is a continuation-in-part of, U.S. patent application Ser. No. 17/004,312, filed 27 Aug. 2020, which claims priority from, and is a continuation-in-part of, U.S. patent application Ser. No. 15/427,332, filed 8 Feb. 2017, which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to a device in the field of fractional treatment, such as but not limited to, for restoring shape and enhancing functionality of body related to the natural opening structure, and particularly to such treatments at different depths in the tissue. 
     BACKGROUND OF THE INVENTION 
     Fractional devices are known for skin treatment. Fractional injuries to the skin and dermis can be delivered by laser systems such as FRAXEL, which sends small beams of erbium glass laser wavelengths into the dermis or alternatively fractional devices as micro-needling, surface ablation or invasive needling. The advantage of these segmental, fractional injury, is the dermis is stimulated with an aggressive fractional trauma providing fractional skin resurfacing, skin tightening, acne scar and wrinkle treatment as well as treatment of hyperhydrosis, acne and trans dermal drug delivery. 
     U.S. Pat. No. 6,210,402 describes a method for dermatological treatment of an external body surface at applying high frequency electrical energy to the electrode terminal comprising multiple conductive elements. 
     U.S. Pat. Nos. 6,148,232 and 6,615,079 describe methods and devices for fractional ablation of stratum corneum for transdermal drug delivery. 
     U.S. Pat. Nos. 8,496,654 and 8,357,157 describe devices for cosmetic fractional epidermis ablation where multiple electrodes are applied to the skin surface and have a grounded return electrode. 
     U.S. Pat. No. 8,579,896 describes fractional coagulation of skin with electrodes configured not to penetrate into the skin. 
     U.S. Pat. No. 9,108,036 describes a skin treatment device including an applicator tip with a plurality of electrodes configured for contacting a stratum corneum layer for delivering RF energy. 
     U.S. Pat. No. 9,480,836 describes a needle array penetrating into the skin and powered by motor connecting to the array. 
     U.S. Pat. No. 9,233,241 describes an array of insertable needles and RF energy delivered to the needles. 
     The fractional RF treatment which was broadly used for skin treatment was totally ignored for medical applications required tissue remodeling inside the natural openings as vagina, anus, nose, ears, mouth and other assessable epithelial tissue. 
     SUMMARY OF THE INVENTION 
     The present invention is a procedure and method for delivery RF energy in fractional manner at different depths in tissues, such as but not limited to, natural openings and adjacent epithelial tissues. Wet environment inside the natural openings does not allow effective RF energy delivery by means of non-insertable electrodes because of significant RF leakage through the liquids. One example of the invention is an applicator configured to be inserted into the natural opening, which includes a mechanism for pushing an array of sharp electrodes through the surface of the epithelial tissue after the applicator is inserted into natural opening. An RF generator is configured for delivering RF energy to the array of electrode. 
     In some embodiments, such as for vaginal treatment, the applicator insertable part has a length of 3-15 cm and smooth surfaces for non-traumatic insertion. The array of electrodes can be designed as needles and the needle surfaces can be partially coated with non-conductive material for delivering more RF energy inside the tissue and less energy to the surface of the vagina and minimize leakage to the liquid presenting around the applicator. 
     The array of electrodes may include two or more conductive elements. The preferable design comprises a minimum of four elements for faster and effective treatment and not more than 25 needles to minimize force of needle insertion into the tissue. Conductive elements can be designed in the shape of needles, cones or pyramids. The length of conductive elements can vary from 0.1 mm up to 10 mm, depending on treatment requirements. The thickness or diameter of the conductive elements ranges from 0.1 mm up to 1 mm. 
     The distance between the conductive element and return electrodes may be at least 3 mm to be able to work in wet environments, such as in the presence of gel or natural liquids. Ideally the distance between electrodes with different polarity should be above 5 mm. 
     The applicator may have a disposable part for inserting into the opening and a non-disposable part that has more expensive mechanical and electronics elements. Alternatively, the entire applicator can be disposable if it is designed in an affordable way. 
     The non-disposable part may be a motor, solenoid or other electro-mechanical component that pushes or otherwise moves the array of electrodes (either directly or indirectly through linkage or intermediary components) toward the treated surface. The actuator may comprise one or more elements and may be electro-mechanical or mechanical, automatic, semi-automatic or manual. The mechanism may push the array of electrodes to the fixed distance or distances controlled by the user or a processor located inside the device. The distance that conductive elements protrude out of applicator is in the range of 0.1 mm up to 10 mm. The conductive elements can be pushed in radial, axial or any other direction required for the treatment. The direction of pushing can be fixed for specific application and alternatively it can be adjustable. 
     The mechanism may hide sharp parts of the conductive elements inside the applicator during moving the applicator inside the opening. 
     The applicator can be used for the treatment of outer body parts adjacent and distal from natural opening. 
     The RF generator generates alternating electrical voltage with frequency of 100 kHz to 40 MHz. The amount of RF energy should be high enough to coagulate and/or ablate the small amount of tissue around the conductive elements but not too high to prevent connection coagulation zones between the conductive elements Minimizing the coagulated zones provides faster healing process. For more aggressive treatment the higher RF energy is applied. 
     The RF pulse power can be varied from 1 W to 500 W depending on the number of conductive elements. RF energy can be delivered with a train of short RF pulses having higher power. RF energy may be applied in a pulsed manner to minimize thermal zone. The pulse duration can be varied from 100 microseconds up to 500 milliseconds. With high RF power shorter pulses are required, whereas with low RF power a longer pulse width is needed to achieve the required thermal effect. 
     The RF energy can be applied between conductive elements in the array. Alternatively, RF voltage can be applied between conductive elements pushed into the tissue and side electrode or electrodes located on the applicator and having a larger area than the total area of conductive elements. 
     Alternatively, a mono-polar scheme can be used when a large area return electrode is placed on the skin surface. 
     The device powering the applicator may include a microprocessor for controlling the electronics and user interface. The microprocessor may monitor one or more from the following RF parameters including, but not limiting to, RF voltage, RF current, RF power, RF impedance, phase shift between RF voltage and RF current. In addition, the controller may control and monitor pushing and retraction of conductive elements. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the accompanying drawings: 
         FIG. 1 a    is a schematic depiction of one example of an applicator with radial direction of conductive elements pushed out. 
         FIG. 1 b    is a schematic depiction of one example of the applicator with radial direction of conductive elements retracted in. 
         FIG. 2  is a schematic depiction of one example of an applicator with axial direction of conductive elements pushed out. 
         FIG. 3  is a schematic depiction of one example of RF current flowing between conductive elements and return electrode. 
         FIG. 4  is a schematic depiction of one example of an applicator attached to the handle. 
     
    
    
     DETAILED DESCRIPTION 
     Referring first to  FIGS. 1 a  and 1 b   , an applicator assembly includes a housing  2 . An array of conductive elements  1  is directed radially and is coupled to a movable part  3  with a connector  4 . By moving the movable part  3 , the array of conductive elements may be retracted and hidden inside the applicator or deployed to protrude out of the applicator to penetrate the tissue surface. 
       FIG. 1 a    shows the applicator with conductive elements pushed outside of the applicator housing toward the treated tissue.  FIG. 1 b    shows the applicator with conductive elements retracted into the applicator. RF current is delivered to the conductive elements through the connector  4  connecting to the RF generator. 
     Referring to  FIG. 2 , an alternative applicator assembly has the array of conductive elements  1  directed axially. Array of conductive elements  1  is coupled to the movable part  3  with connector  4 . By moving the movable part  3 , the array of conductive elements may be retracted and hidden inside the applicator housing  2  or deployed to protrude out of the applicator to penetrate the tissue surface. 
       FIG. 3  shows schematically a cross-section of the assembly attached to the tissue  13 . Array of conductive elements  1  shaped as needles penetrates the tissue and RF current  14  flows from conductive elements  1  to the return electrode  12  having a much larger area than the total area of the array of conductive elements  1 . RF current  14  is concentrated on the sharp conductive elements  1  and creates a strong thermal effect in the vicinity of the needles while heating of tissue near the return electrode  12  is much less. RF energy is high enough to create desired thermal effects, such as coagulation or ablation of the tissue. 
       FIG. 4  shows a disposable applicator  20  designed to contact the tissue of a patient and attached to a handle  24 , which may be connected through a harness  22  to a controller (not shown). The handle  24  includes an electro-mechanical linear actuator  21  that causes movement of the movable part  3  in the disposable applicator to push the array of conductive elements  1  toward the tissue surface. When the linear actuator  21  is pulled back the spring  25  retracts conductive elements out of the tissue. 
     The preferred parameters for device are following: 
     1. Applicator length is from 10 mm to 200 mm 
     2. Applicator diameter (transverse dimension) is from 5 mm up to 40 mm. 
     3. Number of conductive elements can be up to 200 but preferably from 4 up to 25 for easier penetration into the tissue. 
     4. Time of pushing the array of conductive elements toward the tissue should be below 1 second. 
     5. The penetration depth of conductive elements is from 0.1 mm up to 10 mm. For some applications it can be predetermined while for others it should be adjustable. 
     6. RF voltage applied to the skin should be in the range of 10 V up to 1000 V. 
     7. Pulse repetition rate from 0.2 pps up 2 pps 
     The tissue treated by the invention may be, without limitation, skin, fat, muscle or mucosal tissue or any combination thereof. 
     Any of the embodiments of the invention can be used to apply RF energy to tissue. The method includes using the RF energy applicator assembly to apply RF energy to a tissue. For example, in  FIG. 3 , the RF energy applicator assembly includes a housing  30 , RF electrodes  1  coupled to an RF energy source  31  and movably mounted in the housing  30 . The RF electrodes  1  have a retracted position (indicated by broken line  32 ), in which the RF electrodes  1  are retracted inside the housing  30 , and deployed positions in which the RF electrodes  1  protrude out of the housing  30  at different protrusion lengths (indicated by broken lines  33 ,  34  and  35 ; the invention is not limited to this number of lengths). Actuator  36  is coupled to the RF electrodes  1  and configured to move the RF electrodes  1  from the retracted position to any one of the deployed positions. 
     In the method, the actuator  36  is used to move the RF electrodes  1  to one of the deployed positions so that the RF electrodes  1  penetrate into the tissue at a first depth, and the actuator  36  is used to move the RE electrodes  1  to a different one of the deployed positions so that the RF electrodes  1  penetrate into the tissue at a different depth. The RF energy is delivered to the tissue at some time while the RE electrodes  1  are located M the tissue. The RE electrodes  1  are retracted out of the tissue after application of a desired amount of RF energy to the tissue. 
     The RF energy may be delivered while the RE electrodes are or are not moving. The RF energy may be delivered at multiple depths. The RE energy may be delivered during insertion of the RE electrodes into the tissue or during retraction of the RF electrodes from the tissue. 
     The housing  30  includes a flat surface  37  that has left and right sides, and a curved outer shell  38  that extends from the left and the right sides. Return electrode  12  is in the curved outer shell  38 . Return electrode  12  includes a left flat portion  12 L that extends beyond the curved outer shell  38  through the left side into a portion of the flat surface  37 , and a right flat portion  12 R that extends beyond the curved outer shell  38  through the right side into another portion of the flat surface  37 . The return electrode  12  is spaced from the RF electrodes  1 . 
     The RF electrodes  1  may be mounted on a movable arm (like arm  3 ) disposed in the housing. The movable arm has a first position in which the RF electrodes are retracted inside the housing and multiple positions in which the RF electrodes protrude out of the flat surface of the housing at the deployed positions. 
     Accordingly, the RF energy may be delivered between movable electrodes or may be delivered between movable electrodes and a return electrode applied to a tissue surface. 
     One particularly useful application of the invention is for a method for treatment of vaginal tissue. The method includes inserting the applicator (such as that of  FIG. 3  or any other embodiment) inside a natural opening into a vaginal canal, and moving the array of conductive elements to touch or penetrate a vaginal wall or a mucosal tissue. Then at least one pulse of RF energy is applied to the array of conductive elements. The method then includes retracting the array of conductive elements away from the vaginal wall or the mucosal tissue after applying the at least one pulse of RF energy and creating fractional thermal damage in the vaginal wall or the mucosal tissue. 
     As described above, in one aspect of the invention, the conductive elements are needles. Each of the needles may have a length from 0.1 mm to 5 mm RF voltage may be applied between two or more groups of the conductive elements in the array. RF voltage may be applied between the conductive elements that have one polarity and a return electrode that has a larger area than a total area of the conductive elements. 
     In one aspect of the invention, the return electrode includes one or more separate elements. In one aspect of the invention, the return electrode is located on the applicator. Alternatively, the return electrode may be separate from the applicator and placed on a skin surface. 
     The RF energy may have a frequency of 100 kHz to 40 MHz. The RF energy may have power of 1 W to 500 W. 
     In one aspect of the invention, the fractional thermal damage includes micro-scarring of the vaginal wall or the mucosal tissue. 
     In one aspect of the invention, the fractional thermal damage includes ablation of the vaginal wall or the mucosal tissue. 
     In one aspect of the invention, the fractional thermal damage includes collagen contraction of the vaginal wall or the mucosal tissue. 
     In one aspect of the invention, the fractional thermal damage is created around each of the conductive elements, e.g., within a radius of no more than 2 mm. 
     The needles may be at least partially coated by an electrically non-conductive material. 
     In one aspect of the invention, the fractional thermal damage is used to treat urge incontinence, stress urinary incontinence or mixed urinary incontinence. 
     In one aspect of the invention, the fractional thermal damage is used to treat genitourinary syndrome of menopause.