Evaluation of Fractional Bipolar Radiofrequency for the Treatment of Striae

This is an interventional open prospective randomized study, done in two sites.

The main purpose of this study is to evaluate the efficacy of the combination of bipolar radiofrequency potentiated by an infrared light followed by fractional bipolar radiofrequency for the treatment of striae on the abdomen.

In order to have a more complete and accurate study, each technology will also be evaluated separately. This will allow the comparison of the effect of each treatment, in monotherapy or combined.

Stria is a very common condition that affects psychologically and aesthetically a lot of patients. It is a linear atrophic scar. So, to be treated, it needs to have both a superficial and a deep impact.

Several technologies have already been tested for this indication, but none of them have been proved at the same time effective and without a high risk of side effects for all skin types. As radiofrequency is an electrical current, it is not absorbed and does not see melanin. So it can be used on all skin types.

When using fractional bipolar radiofrequency, the current goes from small electrodes to return electrodes. Around the small electrodes appear some epidermal ablation, coagulation and deeper thermal damage. This means it has a superficial and a deep effect.

Using infrared combined with bipolar radiofrequency allows the infrared to pre-heat the skin so as to help the radiofrequency to go deeper in the skin more easily. This has a deep effect in the dermis.

In this study, both technologies will be used. At least 20 patients will be treated in two different sites.

The abdomen of each patient will be divided in four quadrants around the navel. Each quadrant will receive a total of three treatments one month apart:

* One quadrant will be the control (no treatment will be done)
* One quadrant will receive each time only bipolar radiofrequency potentiated by infrared
* One quadrant will receive each time only fractional bipolar radiofrequency
* One quadrant will receive each time first bipolar radiofrequency potentiated by infrared, followed in the same session by fractional bipolar radiofrequency.

The choice of the treatment for each area will be randomized at the enrollment of the patient in the study.

There will be two follow-up sessions 3 and 6 months after the last treatment.

The evaluation will be done mainly by 3D acquisitions. This will allow measuring the length, width and depth of the striae and evaluating their evolution after the treatment.

Some patients, if they agree, will also have in vivo confocal microscopy before the first treatment and 6 months after the last one. This will give more information on the collagen and elastin changes.

Four patients, who accept it, will have biopsies performed before the first treatment and 6 months after the last one to also show the evolution of the skin structure.

Eligibility Criteria:
Inclusion Criteria:

* Male and female subject over 18 years old, with striae on all the abdomen (white or red)
* Consent form signed by subjects
* Affiliation to social security

Exclusion Criteria:

* Electrical implants (pace maker, defibrillator) or superficial metallic implants (gold thread...)
* Pregnant woman
* Woman who can procreate without using an effective birth control
* Deficient immune system due to immunosuppressive diseases such as AIDS or HIV, or use of immunosuppressive drugs,
* Stretch marks resulting from treatment with steroids,
* Treatment with oral retinoids ongoing or stopped less than a year ago, or photosensitizing ongoing or stopped less than 3 months ago
* History of diseases stimulated by heat (recurrent herpes) on the treatment area
* Procedure less than 6 months ago performed on the treatment area,
* History of keloid scarring or difficulty in healing,
* History of allergy to xylocaine (for subjects who will have biopsy)
* Dermatological disorder requiring systemic therapy or local therapy in the area under study,
* Systemic disease in evolution (cancer or history of cancer, heart disease, uncontrolled diabetes, pain syndrome, history of neuropathy)
* Problem of coagulation and / or anticoagulant therapy,
* Vascular lesions or tattoos on the treatment area,
* Vulnerable Person: minor, under protection, deprived of liberty.