Prospective Evaluation of the Safety and Efficacy of a 1060-nm Large Spot Size, Vacuum-Assisted Hair Removal Diode Laser System in Asian/Pacific Fitzpatrick’s Skin Types IV-V Patients

November 2016 | Volume 15 | Issue 11 | Original Article | 1427 | Copyright © November 2016


Sushil T.Tahiliani MD and Harsh S.Tahiliani MD

Skin & Laser Centre, Mumbai, India

Abstract
Laser-based photoepilation of dark skin types demands a delicate combination of appropriate light wavelengths and spot size to achieve optimal epidermal-to-follicular energy absorption ratios. This prospective study assessed the axillary, arm, thigh, and back hair clearing ef cacy of the LightSheer In nity 1060 nm diode laser in 10 Fitzpatrick skin type IV-V patients. Each area was treated up to ve times, at 4-6-week intervals, after which immediate skin responses and adverse events were recorded. Hair count, color and coarseness were assessed before each treatment session, as well as 1, 3, and 6 months following the last session. Both patients and the treating physician rated the degree of improvement with time, and patients also ranked their satisfaction with the treatment outcome. Percent hair reduction from baseline gradually increased with treatment and peaked at 74.6%, 68.4%, and 65.7% for axillary, arm and thigh regions, respectively, 6 months following the last treatment session. Baseline hair growth patterns precluded effective selection of a representative area for hair counting. Patients satisfaction was consistently higher for axillary hair clearance rates, followed by thigh and arm responses. Throughout the follow-up period, the investigator rated 50-67% of the treated axillae as presenting “good” or “very good” hair clearance, and provided similar ratings for 67% of the treated thigh regions at both the 1 and 6 month follow-up sessions. Immediate responses to treatment were mild to moderate and short-lived and no incidents of brosis or scarring were reported. Taken together, the LightSheer In nity 1060 HS Handpiece provided for an ideal ef cacy-safety balance in treating dark-skinned patients, providing for long-term hair clearance with minimal downtime. J Drugs Dermatol. 2016;15(11):1427-1434.

INTRODUCTION

Photoepilation is one of the top five non-invasive medaesthetic procedures performed in the United States, with over 800,000 procedures performed in 2014 alone.1 The technique has become an attractive long-term solution for both hirsutism and hypertrichosis, as well as for normally distributed but unwanted hair growth. It is most widely exploited by Caucasian (73.2%) and female (87.1%) patients within the 35-50-year-old age group (44.9%).1 Photoepilation is founded upon pulsed delivery of light energy to hair follicles, where it is efficiently absorbed by melanin of the residing stem cells and dermal papilla. The inherent optical and thermal properties of the pigmented cells enable selective photothermolysis of the hair and its follicle, with permanent damage to the follicular epithelium and consequential disruption of hair growth.3 At the same time, overlying skin and proximal cells or tissues are spared, due to their lower optical absorption at the deployed wavelength with the appropriate pulse width.Maximal treatment selectivity is secured by laser hair removal devices combining wavelengths selectively absorbed by melanin (700-1200 nm), pulse durations equal to or shorter than the thermal relaxation time of the follicle and high peak power. However, darker skin phototypes with high epidermal melanin concentrations, compete with the targeted hairs and absorb laser energy, which can lead to thermal skin damage18 and reduced therapeutic efficacy. Devices using longer wavelengths of light provide for reduced scatter and deeper light penetration, most advantageous for skin types with high epidermal melanin concentrations,14,19 but require higher fluence to compensate for the reduced thermal effect within the follicle. Overall, these lasers have demonstrated particular clinical relevance in darker skin phototypes but generally require multiple treatment sessions to obtain satisfactory results.4,8,14,16In addition to the aforementioned tunable optical parameters, spot size inversely correlates with dermal scattering, where larger spot sizes are associated with deeper penetration and a consequential reduction in fluence demands.9 Thus, when designed in conjunction with a large spot size, long-wavelength lasers reduce the epidermal-to-follicular energy absorption ratios, rendering them particularly suitable for dark-skinned patients.The LightSheer Infinity with the HS handpiece (Lumenis Ltd.), designed for delivery of fluences of up to 14 J/cm2 over a 22x35 mm area, is equipped with a vacuum chamber, which
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