System and method for skin rejuvenation using impedance monitoring
In part, some embodiments described herein relate to methods of cosmetic treatment. An exemplary method may include disposing a treatment applicator comprising an electrode array comprising a plurality of needles on a portion of tissue such that a region of the electrode array contacts the portion of tissue. The method may also include applying a pulse of radio frequency (RF) energy to the portion of tissue through the electrode array; measuring impedance of electrode array over time; detecting a drop in the measured impedance while electrode array is in contact with the portion of tissue; and upon detection of the reduction in impedance by a threshold value, and terminating application of the pulse of RF energy after a treatment time period.
1 . A method of cosmetic tissue treatment, comprising:
disposing a treatment applicator comprising an electrode array comprising a plurality of needles on a portion of tissue such that a region of the electrode array contacts the portion of tissue, wherein each needle is an electrode in electrical communication with a control system;
applying a pulse of radio frequency (RF) energy to the portion of tissue through the electrode array contacting the portion of tissue;
monitoring an impedance of the electrode array contacting the portion of tissue over time;
detecting a first impedance value of the electrode array before or during monitoring the impedances of the electrode array contacting the portion of tissue over time, wherein the first impedance value is detected before or during monitoring the impedances of the electrode array over time;
following the detection of the first impedance value, continuing monitoring changes to the impedance of the electrode array contacting the portion of tissue over time detecting an initial increase in impedance;
determining, while continuing monitoring impedance changes, that an impedance drop has occurred that meets or exceeds an expected threshold impedance drop while the electrode array is in contact with the portion of tissue following the initial increase in impedance;
initiating a treatment time period in response to the determining that the impedance drop has occurred that meets or exceeds the expected threshold impedance drop following the initial increase in impedance,
wherein the monitored impedance changes of the electrode array over time correspond to impedance changes in the portion of the tissue in contact with the electrode array;
delivering treatment energy during the treatment time period using the plurality of needles, wherein delivery of the treatment energy is initiated by detecting that the impedance drop in the portion of tissue in contact with the electrode array has occurred that meets or exceeds the expected threshold impedance following the initial increase in impedance; and
terminating application of the treatment energy after the treatment time period.
2 . The method of claim 1 , wherein a duration of the pulse is between about 1 ms and about 12 ms.
3 . The method of claim 1 , wherein the impedance of the electrode array over time is monitored at a sampling rate that ranges from about 10 KHz to about 50 KHz.
4 . The method of claim 3 wherein the impedance of the electrode array over time is monitored at a sampling rate of about 30 KHz.
5 . The method of claim 1 further comprising avoiding initiating muscle twitches during treatment time period.
6 . The method of claim 5 wherein the electrode array has an output voltage with a ramp time ranging from about 100 microseconds to about 5 ms.
7 . The method of claim 1 wherein the plurality of needles are connected in parallel.
8 . The method of claim 1 further comprising transforming tissue such that tissue is removed in vicinity of contact with a subset of the plurality of needles.
9 . The method of claim 1 further comprising applying a topical on the portion of the tissue prior to disposing the treatment applicator.
10 . The method of claim 9 further comprising applying a topical on the portion of the tissue after the treatment time period.
11 . The method of claim 9 wherein the topical is a skin moisturizer.
12 . The method of claim 1 wherein the pulse of RF energy travels along surface of electrode and initiates a tissue effect when delivered to the portion of the tissue.
13 . The method of claim 1 wherein one or more annular injuries is generated in tissue in response to the pulse of radio frequency (RF) energy.
14 . The method of claim 1 , wherein the impedance drop corresponds to a break down of one or more outer tissue layers of the portion of the tissue.
15 . The method of claim 1 , wherein the expected threshold impedance is selected to set a duration of the treatment time period or a portion thereof.
16 . An apparatus for treating tissue, comprising:
a first treatment applicator head including a first plurality of needles;
an applicator body having a first end connected to the first treatment applicator head; and
a control system;
wherein the applicator body includes a second end in communication with a radio frequency (RF) power source and the control system;
wherein the first treatment applicator head, when connected to the applicator body, is electrically connected with the RF power source in communication with the second end;
wherein the control system is configured to:
detect an initial increase in impedance
determine, while monitoring impedance changes while the first plurality of needles contact a portion of the tissue, that an impedance drop has occurred that meets or exceeds an expected threshold impedance drop following the initial increase in impedance, and
initiate a treatment time period in response to the determining that the impedance drop has occurred that meets or exceeds the expected threshold impedance drop following the initial increase in impedance, wherein the monitored impedance changes correspond to impedance changes in the portion of the tissue, wherein a timer for the treatment with RF energy is set by the control system in response to the impedance drop being detected following the initial increase in impedance,
wherein the first plurality of needles is configured to deliver treatment energy during the treatment time period,
wherein the control system terminates tissue treatment at end of the treatment time period.
17 . The apparatus of claim 16 wherein each needle of the first plurality of needles has a blunt tip.
18 . The apparatus of claim 16 further comprising a second treatment applicator head including a second plurality of needles, the first end of the applicator body connected to the second treatment applicator head, wherein the second treatment applicator head, when connected to the applicator body, is electrically connected with the RF power source.
19 . A method of treating tissue comprising:
applying radio frequency (RF) power to tissue through a plurality of electrodes, the plurality of electrodes contacting a portion of the tissue, wherein each electrode is a needle in electrical communication with a control system;
during the application of the RF power, monitoring impedance changes of the plurality of electrodes over time;
detecting a first impedance value of the plurality of electrodes before or during monitoring impedances of the plurality of electrodes over time wherein the first impedance value is detected while monitoring the impedances of the electrode array over time;
following the detection of the first impedance value, continuing monitoring changes to the impedance of the electrode array contacting the portion of tissue over time detect an initial increase in impedance;
determining, while continuing monitoring impedance changes, that an impedance drop has occurred that meets or exceeds an expected threshold impedance drop while each needle is in contact with the portion of tissue, wherein the monitored impedance changes correspond to impedance changes in a portion of the tissue following the initial increase in impedance;
controlling the application of RF power based on the monitored impedance changes;
initiating a treatment time period in response to the determining that the impedance drop has occurred that meets or exceeds the expected threshold impedance drop following the initial increase in impedance, wherein the monitored impedance changes of the plurality of electrodes over time correspond to impedance changes in the portion of the tissue over time;
delivering treatment energy during the treatment time period using the plurality of electrodes, wherein delivery of the treatment energy is initiated by detecting that the impedance drop has occurred that meets or exceeds the expected threshold impedance following the initial increase in impedance; and
terminating application of the treatment energy at the end of the treatment time period.
20 . The method of claim 19 , wherein the impedance drop that meets or exceeds the expected threshold impedance is correlated with one or more of the plurality of electrodes contacting an untreated region of tissue.
21 . The method of claim 20 wherein a first conductive property of the untreated region of tissue differs from a second conductive property of a treated region of tissue.
22 . The method of claim 21 wherein the treated region of tissue is disposed above the untreated region of tissue.
23 . The method of claim 19 , wherein RF power is reduced based on a reduction of impedance.
24 . The method of claim 19 , wherein the RF power is applied for a treatment time that ranges from about 1 ms to about 12 ms.
25 . The method of claim 19 , wherein the impedance drop ranges from about 10% to about 90% of the first impedance value.
26 . The method of claim 19 , wherein the impedance drop ranges from about 20% to about 50% of the first impedance value.