Systems and methods for intradermal collagen stimulation

Abstract

The present invention provides systems, apparatus and methods for selective applying energy to a patient's dermis tissue to generate the growth of new collagen in this tissue, while minimizing the effect on the outer epidermis layer, thereby minimizing or suppressing the wound healing phase of the procedure. In one aspect of the invention, a method includes positioning a first electrode adjacent to, or in contact with, a region on or within a patient's skin, and applying a sufficient high frequency voltage between the first electrode and a second electrode to create a heat injury to a target tissue within the patient's dermis layer without ablating the epidermis layer overlying the target tissue. Typically, the voltage applied to the first and second electrodes is sufficient to induce heating of the dermis layer to about 60°-80° C., preferably about 65°-75° C. This induced heating causes the patient's body to undergo a wound healing response in the slightly inflamed tissue of the dermis. The wound healing process involves the generation of neo-collagen in the dermis layer, which fills in the wrinkle in the patient's skin.

What is claimed is:  
     
         1 . A method for treating wrinkles in a patient's skin comprising: 
 positioning a first electrode adjacent to, or in contact with, a region on or within the patient's skin; and    applying a sufficient high frequency voltage difference between the first electrode and a second electrode to create a heat injury to a target tissue within the patient's dermis layer without ablating the epidermis layer overlying the target tissue.    
     
     
         2 . The method of  claim 1  further comprising positioning the first and second electrodes adjacent to, or in contact with, an outer surface of the patient's skin and applying high frequency voltage therebetween such that an electric current passes from the first electrode through the epidermis layer to the target tissue in the dermis layer, and to the second electrode.  
     
     
         3 . The method of  claim 1  further comprising advancing the first electrode through the patient's epidermis layer to the dermis layer before the applying step.  
     
     
         4 . The method of  claim 3  further comprising positioning the second electrode adjacent to, or in contact with, an outer surface of the patient's skin such that the electric current passes from the first electrode, through the dermis layer and the epidermis layer, to the second electrode.  
     
     
         5 . The method of  claim 3  further comprising advancing the second electrode through the patient's epidermis layer to the dermis layer such that the electric current passes from the first electrode through the target tissue in the dermis layer and to the second electrode without passing through the epidermis layer.  
     
     
         6 . The method of  claim 1  wherein the high frequency voltage difference is sufficient to generate a thermally induced controlled inflammation in the target tissue within the dermis to generate neo-collagen.  
     
     
         7 . The method of  claim 1  wherein the high frequency voltage difference is sufficient to induce heating of the target tissue in the dermis to about 60° C. to about 80° C.  
     
     
         8 . A system for treating wrinkles in a patient's skin comprising: 
 an electrosurgical instrument having a shaft with a proximal end portion, a distal end portion and a first electrode on the distal end portion;    a second electrode;    a power supply coupled to the first and second electrodes for applying a high frequency voltage difference therebetween; and    wherein the first and second electrodes are configured, when a sufficient high frequency voltage difference is applied therebetween, to create a heat injury to a target tissue within the patient's dermis layer without ablating the epidermis layer overlying the target tissue    
     
     
         9 . The system of  claim 7  wherein the first and second electrodes are sized and shaped to minimize the current density at the surface of the first and second electrodes.  
     
     
         10 . The system of  claim 7  wherein the first electrode has a sharpened distal end for piercing the patient's skin and advancing through the epidermis layer to the dermis layer.  
     
     
         11 . The system of  claim 9  wherein the second electrode is a dispersive return pad configured for placement on the patient's outer skin surface.  
     
     
         12 . The system of  claim 9  wherein the second electrode has a sharpened distal end for piercing the patient's skin and advancing through the epidermis layer to the dermis layer.  
     
     
         13 . A method for treating wrinkles in a patient's skin comprising: 
 positioning first and second electrodes within a target region in the dermis layer; and    applying a sufficient high frequency voltage difference between the first and second electrodes to create a thermally induced injury to the tissue in the target region.    
     
     
         14 . The method of  claim 12  further comprising advancing the first and second electrodes through the epidermis layer to the dermis layer.  
     
     
         15 . The method of  claim 12  wherein the first and second electrodes comprise needle-shaped electrodes having a distal exposed portion, and a proximal insulated portion.  
     
     
         16 . The method of  claim 12  further comprising positioning a third electrode within the target region of the dermis layer and applying a high frequency voltage difference between the third and first electrodes and between the first and second electrodes.  
     
     
         17 . The method of  claim 12  further comprising positioning an array of electrodes within the target region of the dermis layer and applying a high frequency voltage difference between the array of electrodes and the first electrode.  
     
     
         18 . The method of  claim 1  wherein the high frequency voltage difference is sufficient to generate a thermally induced controlled inflammation in the target tissue within the dermis to generate neo-collagen.  
     
     
         19 . The method of  claim 1  wherein the high frequency voltage difference is sufficient to induce heating of the target tissue in the dermis to about 60° C. to about 80° C.  
     
     
         20 . A device for treating tissue comprising: 
 an electrosurgical instrument having a proximal end portion, a distal end portion and an electrode assembly on the distal end portion; and    wherein the electrode assembly comprises at least first and second elongate electrodes extending from the instrument, each electrode having pointed distal ends for piercing tissue, insulated proximal portions and exposed distal portions, wherein the exposed distal portions are axially spaced a substantially equivalent distance from the instrument.    
     
     
         21 . The device of  claim 18  further comprising a third elongate electrode extending from the instrument, wherein the first, second and third electrodes are aligned with, and spaced from, each other and the exposed distal portions are axially spaced a substantially equivalent distance from the instrument.  
     
     
         22 . The device of  claim 18  further comprising an array of elongate electrodes extending from the instrument, wherein each electrode has an exposed distal portion that is spaced from the other exposed distal portions and spaced a substantially equivalent distance from the instrument.  
     
     
         23 . The device of  claim 18  wherein the electrodes each have a guard portion proximal to the insulated proximal portion, the guard portion having a diameter larger than the insulated proximal portion and configured to function as a stop to prevent the guard portion of the electrodes from being advanced into the tissue.  
     
     
         24 . A method for treating wrinkles in a patient's skin comprising: 
 positioning first and second electrodes adjacent to, or in contact with, an outer surface of the patient's skin; and    applying a sufficient high frequency voltage difference between the first and second electrodes such that electric current flows from the first electrode through target tissue in the patient's dermis layer to the second electrode without ablating the epidermis layer overlying the target tissue.    
     
     
         25 . The method of  claim 24  further comprising wherein the positioning step is carried out by positioning the first and second electrodes on either side of a wrinkle, the method further comprising translating the electrodes along the length of the wrinkle during the applying step.  
     
     
         26 . The method of  claim 24  further comprising spacing the first and second electrodes a distance sufficient to cause the electric current to pass through the epidermis into the target tissue in the dermis layer.  
     
     
         27 . The method of  claim 24  further comprising spacing the first and second electrodes about 5 to 20 cm from each other.  
     
     
         28 . The method of  claim 24  further comprising minimizing current density in the epidermis during the applying step.  
     
     
         29 . The method of  claim 28  wherein the minimizing step is carried out by selecting electrode shapes that provide a homogenous current distribution around the electrodes.  
     
     
         30 . The method of  claim 24  wherein the first and second electrodes comprise rounded shapes with substantially no edges.  
     
     
         31 . The method of  claim 24  further comprising providing an electrically conductive fluid between the first and second electrodes and the outer surface of the patient's skin.  
     
     
         32 . The method of  claim 31  wherein the providing step is carried out by coating the surfaces of the electrodes with an electrically conductive fluid.  
     
     
         33 . The method of  claim 24  further comprising coating the electrode surfaces with an electrically conductive hydrogel and soaking the hydrogel with an electrically conductive liquid.  
     
     
         34 . A system for treating wrinkles in a patient's skin comprising: 
 an electrosurgical instrument having a shaft with a proximal end portion, a distal end portion and a first electrode on the distal end portion;    a second electrode;    a power supply for applying a high frequency voltage difference between the first and second electrodes; and    wherein the electrodes are configured such that, when the first and second electrodes are spaced from each other adjacent to, or in contact with, an outer surface of a patient's skin and a sufficient high frequency voltage difference is applied therebetween, electric current passes from the first electrode through target tissue in the patient's dermis to the second electrode without ablating the epidermis layer overlying the target tissue.    
     
     
         35 . The system of  claim 34  wherein the second electrode is coupled to the electrosurgical instrument such that the first and second electrodes are spaced from each other by a distance of about 5 to 20 cm.  
     
     
         36 . The system of  claim 34  wherein the second electrode is coupled to the electrosurgical instrument such that the first and second electrodes are axially spaced a substantially equivalent distance from the instrument shaft.  
     
     
         37 . The system of  claim 34  further comprising a second electrosurgical instrument having a proximal end portion and a distal end portion, wherein the second electrode is coupled to the distal end portion of the second instrument.  
     
     
         38 . The system of  claim 34  wherein the first and second electrodes comprise rounded shapes with substantially no edges.  
     
     
         39 . The system of  claim 34  wherein the first and second electrodes comprise a spherical or hemispherical shape.  
     
     
         40 . The system of  claim 34  further comprising an electrically conductive fluid located at the surfaces of the first and second electrodes.  
     
     
         41 . The system of claim  40  wherein the electrically conductive fluid comprises an electrically conductive hydrogel coated on the surfaces of the electrodes.  
     
     
         42 . The system of claim  41  wherein the hydrogel is soaked with an electrically conductive liquid.