TOPICS

Efficacy of a Low Fluence, High Repetition Rate 810nm Diode Laser for Permanent Hair Reduction in Indian Patients with Skin Types IV–VI

aMadhuri Agarwal, MBBS, MD (SKIN & VD), DDV; bSangeeta Velaskar, MBBS, MD (SKIN & VD), DVD; cMichael H. Gold, MD

aDepartment of Dermatology, Yavana Aesthetics Clinic, Mumbai,India

bMedical Services and R & D, Kaya Ltd., Mumbai, India

cGold Skin Care Center, Nashville, Tennessee

Disclosure: The authors report no relevant conflicts of interest.


Abstract

Background: The study’s aim is to evaluate the novel “in motion” technique for permanent hair removal using a low level fluence/high repetition rate on patients with a dark skin type over different areas of the body. Objectives: To assess fluence, accumulative energy, and number of treatments needed to achieve a significant hair reduction and patient satisfaction with minimal side effects, low discomfort levels, and high safety profile in a skin type IV–VI Indian patients. Methods: Seventy-one Indian female patients with skin type IV–VI were enrolled in the study. All patients were treated with a low fluence, high repetition rate 810nm diode laser using a predetermined set of parameters for 5 to 6 treatments in 1- to 3-month intervals. Hair reduction was measured by patients’ satisfaction and all adverse effects were documented. Results: Results obtained a high degree of patient satisfaction and a very low record of adverse events. Treatments were complication-free for dark skins and a reasonable schedule or sessions and intervals .The discomfort during the sessions was negligible. J Clin Aesthet Dermatol. 2016;9(11):29–33


Hair removal using laser technologies has improved significantly over the past few years and is one of the most common dermatologic procedures today.[1] Based on the selective photothermolysis mechanism, modern technologies inspire to increase hair removal efficacy, which is partially related to skin color, mostly dark skinned or tanned patients.[2],[3] Optimal candidates for laser treatments as of today are still light-skinned patients with dark, thick hair.

Routinely, a variety of lasers and pulsed light sources are available for hair removal with efficacy and safety varying from different wavelengths and technology.[2] Initial results have demonstrated using the 1064nm Q-switched neodymium-doped yttrium aluminium garnet (Nd: YAG) laser combined with topical carbon mineral oil suspension for long-term hair removal was unsatisfactory and only temporary.[4] Later, more promising results were achieved by targeting melanin as the target chromophore using a 694nm long pulsed ruby laser,[5] a 755nm long-pulsed alexandrite laser,[6] an 800nm diode laser,[7] and a range of flashlamp pulsed-dye lasers.[8]

To overcome the limitation of dark skin types, an 810nm diode laser has been proposed as a solution by using low fluence that decreases side effects related to dark skin color while maintaining efficacy.[9] It does this by using a high repetition rate yielding appropriate amounts of cumulative energy in the hair bulb and bulge.

Seventy-one female patients with dark skin (type IV–VI) were enrolled in this clinical study and underwent 5 to 6 treatments in areas of interest using the novel “in motion” method for hair removal. The same operator, to eliminate any potential discrepancies, performed all of the treatments in the same clinic.

METHODS

Patients. This trial enrolled 71 patients, all female, between 18 and 41 years of age (mean age 29), with Fitzpatrick skin types IV–VI. They were all treated with the Soprano XLi 810nm diode, SHR mode (Alma™ Lasers, Israel).

Out of the total number of patients, 51 were treated at the smaller body areas (bikini area, face, or axilla) and 20 patients were treated in the larger body areas (chest, back, abdomen, and hands). Patients were informed regarding all aspects of the clinical trial and signed the approved informed consent form. Photographs of the treated area were taken with a digital camera keeping lighting conditions and position constant. Each treated body part was photographed at the first session, before each following session, and at six months after the last session.

The exclusion criteria included patients less than 18 years of age, pregnancy, lactation, scars or infection in the treatment area, and/or a history of scarring and repeated herpes infections. Criteria for admission permitted the enrollment of patients with skin type IV.

Laser system and treatment. The system used in the clinical trial has two main modes—the hair removal (HR) mode and the super hair removal (SHR) mode.

In this study, all patients were treated using the SHR mode. This mode incorporates low fluence (maximal fluence is 20J/cm2), high repetition rate (up to 10Hz), and high average power in order to create a photothermal effect, which damages the hair follicle’s ability to regenerate the hair. When using this mode, the delivered energy is accumulated in low doses (below adverse event threshold) in a pre-defined grid area while the hand piece, with its cooled tip, is kept in a constant motion (in motion technique). With this technique, uniform area coverage is achieved with minimal discomfort and with high safety and efficacy profiles for all skin types.

Prior to all of the treatments, the area was photographed, shaved, and divided to 150cm² grids at the larger body areas and to 50cm² grids at the smaller ones. A fine layer of treatment gel was placed in order to enable smoother movement of the handpiece and to allow for better cooling of the area. The fluence parameters were at the range of 3 to 10J/cm², the accumulated energy parameters were at the range of 1.5 to 10kJ, and the number of treatment and treatment intervals were determined according to specific laser-treated areas. The laser repetition rate was constant at 10Hz throughout the course of the study.

The handpiece was placed inside the grid’s boundaries and moved according to the in motion technique—lateral movement in a constant sweeping mode at a speed of approximately 10cm per second. After accumulating the needed energy at the specific grid, the handpiece was moved to the adjacent one, covering all the grids that were marked during the treatment assessments.

Hair reduction was evaluated objectively by the investigator comparing the photos taken before the first treatment and six months after the last session using the GAIS scale. The patients assessed the satisfaction rate subjectively six months after the last session using the same GAIS scale. The GAIS scores evaluated both by investigator and patient were as follows: no results, poor=0–25 percent, average=25–50 percent, good=50–75 percent, and excellent=75–100 percent.

The patients also had to assess the amount of discomfort experienced during the laser sessions based on the international scale .The degree of pain was classified from 0 to 10 in accordance with the Numeric Pain Rating Scale: very high (10–8), high (7–5), average (4–2), and low (1–0).10 The investigator noted all adverse events during the course of the study.

The GAIS scores and extended treatment scores are shown in Table 1 .

RESULTS

A total of 71 female patients aged 18 to 41 with a Fitzpatrick IV–VI skin type were included in the study. Of the total number of participants, 51 (71.83%) patients were treated at the smaller body area (bikini, face, axilla) and 20 (28.17%) patients were treated at the larger ones (chest, back, abdomen, and hands). All patients had a moderate to high hair density and 1 to 3 hair type (data to be examined by physician). Subjects underwent an average of 5.2 (range 3–9) treatments with an average of 2.13-month intervals.

The subjective evaluation of improvement by patients was as follows: excellent in 58 patients, good in five, average in five, and poor in three. The objective assessment by physicians carrying out the treatment scored as follows: excellent in 60 patients, good in five, average in four, and poor in two. No patient was observed to have no results.

The results were average to poor in the bikini area. In this area, both the physician (7/9 cases of bikini) and the patient (8/9 cases of bikini) reported poor to average results. In eight cases, the patients had to undergo 5 to 6 additional sessions in the bikini area to achieve good results. The results are shown in Figure 1.

Pain was also assessed. Sixty-nine patients (95.8%) had very low to no discomfort during their sessions, two (1.44%) had average discomfort, and one (0.72%) had high discomfort in the upper lip area. None of the patients experienced very high pain or discomfort. No immediate or long-term adverse effects were reported in any of the patients. There was no incidence of burns, hyperpigmentation, or hypopigmentation reported in any of the patients. This is of utmost importance in patients with skin type IV–VI as burns and pigment changes are frequently observed adverse effects and discourage both physicians and patients from opting for laser hair reduction in a darker skin type.

DISCUSSION

Multiple lasers and light-based technologies are available for hair removal. Diode lasers have become the gold standard in the last few years in most parts of the world. Nevertheless, most studies conducted using lasers present decreased efficacy and an increase in side effects in darker skinned patients. Using the novel “in-motion” technique that is known to decrease discomfort and side effects, this current study showed that even for patients with skin type IV–VI, removal of unwanted hair could be performed with no side effects or significant pain. The basis behind the presented technology is applying low average energy with a high repetition rate on a defined area of the treatment. This enables the hair bulb to heat stack gradually to the point of destruction, and in the same time protect the epidermis with the handpiece’s cooled tip. These features are even more important when treating darker skin of color due to the higher melanin concentration found in the epidermis of those with darker skin. By applying a high repetition rate and by constantly moving the handpiece, no part of the skin is stacked with more than 10J/cm2 and it is safe from skin burns and pain.

In the authors’ study, 71 patients were treated in various areas of the body with no incidence of hyperpigmentation, hypopigmentation, or burns. Moreover, 95.8 percent of participants reported low to no discomfort throughout all of the treatment sessions. Only one patient (0.72%) complained of a high level of discomfort. Furthermore, the “in-motion” technique combined with low fluence, high repetition rate, demonstrated a statistically significant hair reduction seen both by patients’ subjective evaluation and physicians’ objective evaluation. Comparing these results demonstrates a high correlation between subjective and objective evaluations.

The results indicate a 75- to 100-percent improvement, objectively and subjectively (84.5 percent and 81.7 percent, respectively). Satisfactory results (50- to 75-percent improvement) were reported in seven percent (both objectively and subjectively), and an additional 5.6 percent (objectively) and seven percent (subjectively) were scored as an average improvement of a 25- to 50-percent reduction in hair density. For the additional 2.8 percent and 4.2 percent, respectively, the reduction was assessed as poor improvement (0–25%), but these results were noted in a single treatment area only.

The efficacy examined according to the treatment area points out that there is a discrepancy in performance. Both the patients’ satisfaction and the physicians’ assessment were extremely high in all areas of the body except the bikini line. This area was scored as average to poor in 7 of 9 cases in the objective assessment and 8 of 9 in the patients’ subjective assessment. These results were reported for an average of 5.1 treatments, but an additional 5 to 6 treatments improved all of these cases to the level of 50- to 75-percent reduction assessment. All of the other areas, big and small, had outstanding results to the treatment and yielded an excellent GAIS scored by patients and the physician.

CONCLUSION

The authors conclude that the study laser’s low fluence, high repetition rate produces high performance in hair removal results with virtually no adverse effects. The treatment is very well accepted and patients and practitioners are highly satisfied with the results. Overall, this unique technology has proven effective and safe for patients with dark skin types.

There are few studies documenting the safety and efficacy of low fluence, high repetition rate 810nm diode lasers in Fitzpatrick skin types IV–VI. This is a first of its kind Indian study of the “in motion” low fluence, high repetition 810nm diode laser system in a large number of patients (71 patients) demonstrating a high degree of safety and efficacy. A limitation of this study is that this laser system was not compared to other laser systems.

References

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0. Acute Pain Management (1992) Operative or medical procedures and trauma. Clinical practice guideline. N-1. AHCPR. Publication No. 92-0032. Agency for HealthCare Research and Quality, Rockville, MD; pp. 116–117.

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