Devices and methods for fractional treatment of tissue

1 . A tissue treatment device comprising:

a plurality of spaced-apart elongated electrodes configured to:

receive a radio frequency (RF) signal at a first polarity from an RF energy source; and

be inserted into the tissue at one or more depths;

a single flat electrode located distally to the elongated electrodes on an axis X, the single flat electrode being perforated and having a plurality of holes corresponding to a positioning of the plurality of spaced-apart elongated electrodes, wherein the plurality of spaced-apart elongated electrodes are configured to pass through the holes towards the tissue, wherein the single flat electrode is configured to contact a tissue surface of the tissue and receive the RF signal from the RF energy source, at a second polarity being opposite to the first polarity;

wherein a first plurality of the plurality of the spaced apart elongated electrodes is mounted as a first planar array on a first stage positioned proximally of the single flat electrode along the axis X, the first array of elongated electrodes being oriented distally of the first stage;

wherein a second plurality of the plurality of spaced apart elongated electrodes is mounted as a second planar array on a second stage positioned proximally of the first stage along the X axis, the second plurality of elongated electrodes being oriented distally of the second stage;

the first stage further comprising a second plurality of holes among the spaced apart elongated electrodes of the first stage corresponding to the plurality of spaced apart electrodes of the second stage along the axis X to enable passage therethrough of elongated electrodes of the second stage through the second plurality of holes in the first stage;

the elongated electrodes of the first stage and the elongated electrodes of the second stage being oriented along the X axis so as to pass through the plurality of holes in the single flat electrode;

an actuator connected to the first and second stages and configured to selectively and independently move the plurality of elongated electrodes in the first stage and in the second stage along the axis X, in two opposite directions through the plurality of holes in the single flat electrode into and out of the tissue; and

a controller connected to the plurality of elongated electrodes on the first stage and on the second stage, the flat electrode, the RF energy source, and the actuator configured to:

apply RF energy to the tissue; and actuate the actuator to selectively and independently insert and remove the first and second plurality of elongated electrodes into and out of the tissue, to different depths into the tissue, to provide fractional treatment to the tissue in multiple depths.

2 . The tissue treatment device according to claim 1 , wherein the controller is configured to operate the RF energy source in an insertion phase and a subsequent treatment phase, the insertion phase comprises applying the RF signal to the plurality of elongated electrodes on the first and second stages to cause ablation of the tissue in contact with the distal ends of the elongated electrodes, wherein the ablation caused by the RF signal in the insertion phase is sufficient to insert the elongated electrodes into tissue without mechanical insertion force.

3 . The tissue treatment device according to claim 1 , wherein the controller is further configured to vary spatial density of the fractional treatment over a treatment time period by operating the actuating mechanism to selectively and independently move the plurality of elongated electrodes in first and the second stages.

4 . The tissue treatment device according to claim 3 , where said spatial density is varied between a first distance between each two adjacent spaced-apart elongated electrodes and a second distance between each two adjacent spaced-apart elongated electrodes equaling 1/√{square root over (2)} of the first distance.

5 . The tissue treatment device according to claim 4 , wherein said first distance is equal to 2.2 mm.

6 . The tissue treatment device according to claim 4 , wherein said first and second distances are equal.

7 . The tissue treatment device according to claim 6 , wherein said first and second distances are equal to 2.2 mm.

8 . The tissue treatment device according to claim 1 , wherein, when each elongated electrode of the second array is inserted into the tissue, each elongated electrode is located equidistant to every four adjacent elongated electrodes of the first array.

9 . The tissue treatment device according to claim 1 , wherein said actuator comprises a first actuating motor connected to the first array and a second actuating motor connected to the second array, the first and second actuating motors being independently controllable by the controller.

10 . The tissue treatment device according to claim 1 , wherein the elongated electrodes of said first planar array have an equal first length and the elongated electrodes of said second planar array have an equal second length.

11 . The tissue treatment device according to claim 1 , wherein said plurality of elongated electrodes have different lengths.

12 . The tissue treatment device according to claim 1 , wherein said one or more depths comprise a maximal depth of between 7-10 mm.

13 . The tissue treatment device according to claim 1 , wherein at least some of the plurality of elongated electrodes have a flat body.

14 . The tissue treatment device according to claim 13 , wherein the flat body of each electrode of said first array has a length of 3 mm and width and thickness of 100-200 μm each.

15 . The tissue treatment device according to claim 13 , wherein the flat body of each electrode of said second array has a length of 7 mm and width and thickness of 200-300 μm each.

16 . The tissue treatment device according to claim 1 , wherein at least some of the plurality of elongated electrodes have at least one of:

a curved body;

a blunt distal end;

a pointed distal end;

different cross-sectional shapes;

different cross-sectional areas;

insulation along a proximal external surface thereof; or

insulation along whole external surface except of a bottom side thereof.

17 . The tissue treatment device according to claim 1 , wherein at least some of the plurality of elongated electrodes are arranged in a plurality of comb-like one dimensional arrays.

18 . The tissue treatment device according to claim 1 , comprising:

a main body configured to be held by a user, the main body housing the actuator and the controller; and

a disposable tip removably connectable to the main body and housing the plurality of elongated electrodes and the flat electrode.

19 . The tissue treatment device according to claim 18 , further comprising an RF energy source being housed within the main body.

20 . The tissue treatment device according to claim 19 , wherein the controller is further configured to vary spatial density by actuating the mechanism as follows:

a) during insertion phase, operate the RF energy source at a first RF signal profile that causes ablation of tissue contacting distal ends of the plurality of elongated electrodes, and operate the actuating mechanism to move the plurality of elongated electrodes into the tissue;

b) during treatment phase, operate the RF energy source at a second RF signal profile that causes treatment of tissue contacting the distal ends of the plurality of elongated electrodes, for a predetermined treatment period; and

c) during disengagement phase, operate the actuating mechanism to move the plurality of elongated electrodes out of the tissue.

21 . The tissue treatment device according to claim 20 , wherein said controller is further configured to sequentially repeat said (a) and (b) operations for two or more times corresponding to the at least two different sub-groups of the plurality of elongated electrodes, to thereby vary spatial density of the treatment.

22 . The tissue treatment device according to claim 20 , wherein said controller is configured to operate the RF energy source at a third RF signal profile during the disengagement phase.

23 . A method for fractional treatment of tissue, the method comprising:

providing a plurality of spaced-apart elongated electrodes configured to: receive a radio frequency (RF) signal at a first polarity from an RF energy source and be inserted into the tissue at one or more depths;

providing a single flat electrode located distally to the elongated electrodes on an axis X, the single flat electrode being perforated and having a plurality of holes corresponding to the positioning of the plurality of spaced-apart elongated electrodes, wherein the plurality of spaced-apart elongated electrodes are configured to pass through the holes towards the tissue, wherein the single flat electrode is configured to contact a tissue surface of the tissue and receive the RF signal from the RF energy source at a second polarity being opposite to the first polarity;

wherein a first plurality of the plurality of the spaced apart elongated electrodes is mounted as a first planar array on a first stage positioned proximally of the single flat electrode along the axis X, the first array of elongated electrodes being oriented distally of the first stage;

wherein a second plurality of the plurality of spaced apart elongated electrodes is mounted as a second planar array on a second stage positioned proximally of the first stage along the X axis, the second plurality of elongated electrodes being oriented distally of the second stage;

wherein the first stage further comprises a second plurality of holes among the spaced apart elongated electrodes of the first stage corresponding to the plurality of spaced apart electrodes of the second stage along the axis X to enable passage therethrough of the elongated electrodes of the second stage through the second plurality of holes in the first stage;

wherein the plurality of elongated electrodes of the first stage and the plurality of elongated electrodes of the second stage are oriented along the X axis so as to pass through the holes in the single flat electrode;

wherein an actuator is connected to the first and second stages and configured to selectively and independently move the plurality of elongated electrodes in the first stage and the second stage along the axis X, in two opposite directions through the plurality of holes in the single flat electrode into and out of the tissue; and,

wherein a controller is connected to the plurality of elongated electrodes on the first stage and the second stage, the flat electrode, the RF energy source, and the actuator;

the method further comprising, under control of the controller:

placing the single flat electrode in contact with a tissue surface and the tips of the plurality of elongated electrodes into contact with the tissue surface, through the plurality of holes of the single flat electrode;

applying RF energy to the tissue, wherein the applying comprises applying the RF signal to the elongated electrodes at the first polarity and to the single flat electrode at the second opposite polarity; and,

inserting and removing, by the actuator, while supplying the RF signal, the elongated electrodes on the first stage and on the second stage into and out of the tissue at different depths into the tissue selectively and independently to provide fractional treatment to the tissue in multiple depths.

24 . The method according to claim 23 , further comprising:

measuring impedance of the tissue; and

determining the RF signal based on the measured impedance.