Review of Alster TS et. al. Effect of a novel low-energy pulsed-light device for home-use hair removal

June 2, 2009

Dermatol Surg. 2009 Mar;35(3):483-9.

Effect of a novel low-energy pulsed-light device for home-use hair removal

Alster TS, Tanzi EL.

Review copyright 2009

This appears to be the first clinical study of the Silk’n home use intense pulsed light for hair removal.  The authors call this “the beginning of a major trend in laser dermatology.”  Given the nicely performed study, and promising results presented, they may be right.

In this study, hair removal was evaluated in one or more treatment areas of twenty women, while matched control areas were left untreated.  The subjects generally had lighter skin and darker hair, and treated areas included underarms, forearms, legs, and bikini lines.  Hair counts were performed in treatment areas and control areas, using a reliable method of manual hair counts (average of 3 manual counts in a 2cm2 or 3cm2 template).  Follow-up measurements were performed at 3 and 6 months, which is generally accepted as the appropriate time frame to assess permanent hair reduction.

The results were quite impressive – virtually no change in hair counts of the control sites at any time, but significant reductions in hair counts (36% to 53% depending on body location) at six months.

While small, this study was appropriately powered and appropriately controlled, and used objective, quantitative outcome measures.  While it would have been nice if the study included multiple sites to eliminate the potential for site bias, a single site study is reasonable for the early stage of clinical work and small size of the study.  (According to a company press release in March 2008, more than 150 patients were treated at 4 total centers, where the results of this first study were successfully replicated.  AestheticDeviceReview hopes these results are published soon.)

A curious point of this study is the 2-week intervals in the series of 3 treatments in the study.  Typically, laser hair removal is performed with at least 4-week intervals between treatments, to maximize the amount of hair follicles in the anagen phase, which is thought to provide the best results.  Perhaps, in addition to their novel device, this novel application of bi-weekly treatments contributes to the results.  Further study is needed here.

The study’s author, Dr. Alster, purchased stock options in the company subsequent to the study.  Given these results, and the reported results from the expanded data set, we can expect these options to become quite valuable.


Review of Bousquet-Rouaud, High-frequency ultrasound evaluation of cellulite treated with the 1064 nm Nd:YAG laser

March 8, 2009

J Cosmet Laser Ther. 2009 Mar;11(1):34-44

High-frequency ultrasound evaluation of cellulite treated with the 1064 nm Nd:YAG laser.

Bousquet-Rouaud R, Bazan M, Chaintreuil J, Echague AV.

Dermatological Laser Unit, Millenium Clinic, Montpellier, France.


This article presents the first evaluation of the use of a high-power pulsed Nd:YAG laser for the treatment of cellulite.  Three of the four authors are employees of Candela Corporation, the maker of the laser.

The study at first appears to be well-designed.  Quantitative endpoints of dermis thickness and ultrasound density were chosen, and preliminary studies were performed to show that measurement methods were not subject to intra-observer or inter-observer error.  Twelve patients were treated, with one thigh randomized to treatment and the other randomized to control.  In addition to pre-treatment ultrasound measurements, follow-up measurements were performed at 1 month and 3 months after the final treatment of the series of three treatments.  Adjunctive photographs were taken before each treatment, and presumably at the follow-up visits.  The example photograph appears to be of high quality.  The treatments were appropriately standardized to minimize the impact of dosage variation on outcome.  Likewise, the patient population appears to be reasonably homogenous in terms of age, body mass index, and pre-treatment evaluation of cellulite severity, to minimize the impact of patient variation on outcome variation.

Given the apparent care taken in the study design, the analysis was extremely disappointing.  The analysis presents only the variation in ultrasound measurements of the treated thigh, and completely ignores the control thigh.  The authors claim that the mean dermal thickness of treated thighs decreases from the beginning to the end of the study, but this is a flawed claim.  Because they do not present data on the control thigh, we cannot know if this result stems from a treatment effect, or from a natural variation in the patient population over time.  For all we know, the dermal thickness of the control thigh improved more than the treated leg.  This is the whole point of having a control thigh.  No other control variables, such as BMI or weight, were presented.

Further, the authors include the raw data for the dermal thickness measurements in all 12 patients, but offer no explanation why some patients have increased thickness at 1 month follow-up which then decreases at 3 months, while other patients show decreased thickness at 1 month with subsequent increases at 3 months.  Presumably, the treatment effect would go in generally the same direction in this homogeneous group that recieved the same treatment regime.  This variation adds to the concern that something else was going on with these patients during the study that might effect dermal thickness.  The same comments apply to the raw data on dermal echogenicity.

The exclusion of measurements of the control thigh from the analysis renders any conclusions moot.  The authors further present patient satisfaction data.  This type of data is notoriously challenging to interpret, as patients often feel satisfied that they are taking steps towards treating a condition. In this case, on average the patients reported being somewhat satisfied, and no patients reported being very satisfied.  Readers of the article should not be satisfied at all.

Review of Khatri KA et. al. Efficacy and safety of a 0.65 millisecond pulsed portable ND:YAG laser for hair removal.

March 1, 2009


J Cosmet Laser Ther. 2009 Feb 6:1-6

Efficacy and safety of a 0.65 millisecond pulsed portable ND:YAG laser for hair removal.

Khatri KA, Lee RA, Goldberg LJ, Khatri B, Garcia V.

Skin & Laser Surgery Center of New England, MA and Nashua, NH, USA.

In this 6 patient study, Khatri et. al. evaluate the AeroLase portable Nd:YAG laser for laser hair removal (LHR).  While the results appear promising, the conclusion that this device is “as effective and safe as other devices for LHR” is simply not supported.  The main study flaws include a very small number of patients treated, poorly performed hair counts, and a complete lack of statistical analysis.  The authors even neglected to report the variances around mean hair count reductions.
A strength of the study is the use of an internal control site, as half the axilla was treated and half was untreated.  The treated half (either upper or lower) was alternated among consecutive patients.  Two treatment regimes (high and low fluence) were studied, one on the left side and one on the right, again alternated among patients. In both cases, randomization would normally be preferred to alternation; however, randomization in such a small number of patients might have resulted in unequal groups. The treatment protocol consisted of a series of four monthly treatments, followed by a one-month and four-month follow up visits.   A single, presumably unblinded, individual counted hairs in treated and control sites, pre-treatment and at both follow-up visits.


At the four month follow up, which is a meaningful period for evaluation of permanent hair reduction, the study showed mean reductions in hair counts at both the treated sites (76%) and the control sites (36%).  The authors attribute the reduction at the control sites to “diffusion of energy from the treatment side to the control side.”  In most other studies, a standard (e.g. 1cm2) area within each of the control and treatment sites is chosen for the hair count, with sufficient spacing to eliminate any potential energy diffusion.  In this study, unfortunately, the authors do not disclose how the hair counts were performed, or how the same areas were counted at each of the time points in the study.  Therefore, it is difficult to compare these results to other studies.  Further, the authors do not describe the variance around the mean hair reductions, or the number of patients who achieved greater hair reduction at the treated site than at the control site.  Consequently, it cannot be determined whether the different results in the treated and control sites are statistically significant.


The six patients self-reported satisfaction, resulting in 1 patient dissatisfied, 2 patients satisfied and 3 very satisfied. Patient satisfaction is often unrelated to clinical outcomes, as patients may be satisfied that they particpated in a treatment, even if no objective improvement was measured.  So, satisfaction data must be taken with a grain of salt.  The patients were not asked to evaluate improvement of treated sites versus control sites, which might have provided more meaningful data. 


Unsurprisingly, histology from treatment site biopsies showed qualitiative changes similar to those described in other articles about light-based hair removal devices.  No conclusions of effectiveness could be drawn however, as quantitative histological analysis was precluded by the limited sample size (two patients) and lack of biopsies of control sites.


Contrary to the authors’ conclusions, for a given number of treatments, the Aerolase device is not likely to achieve comparable results to a higher fluence, larger spot laser with integrated skin cooling.  Skin cooling clearly increases the margin between an effective treatment fluence and over-treatment, higher fluences clearly increase the effectiveness of hair reduction, and larger spot sizes (10mm or greater radius) increase the depth of optical penetration, further enhancing results.


Nevertheless, to provide effective results, the Aerolase may simply require more treatment sessions than the higher-fluence, integrated cooling devices.  A significantly larger study, with improved hair-count measurement methods, is required to fully elucidate the capabilities of this device.


Review of Faurschou A, Pulsed dye laser vs. intense pulsed light for port-wine stains

February 22, 2009

Br J Dermatol. 2008 Dec 11.


Pulsed dye laser vs. intense pulsed light for port-wine stains: a randomized side-by-side trial with blinded response evaluation.


Faurschou A, Togsverd-Bo K, Zachariae C, Hædersdal M.


Department of Dermatology, Bispebjerg Hospital, University of Copenhagen, DK-2400 Copenhagen NV, Denmark.


This study is from the same Denmark group that recently compared the pulse dye laser (LPDL) to the intense pulsed light (IPL) for the treatment of photoaging.  In this study, Annesofie Faurschou reports another head-to-head study comparing these two device types, this time for the treatment of portwine stains.  The study was supported by the laser manufacturer and the local sales agent for the IPL, but neither sponsor participated in the conduct or analysis of the study.  In particular, this study compared the Candela VBeam Perfecta (long pulse 595nm dye laser) with the Palomar StarLux IPL with a Lux G handpiece.

The study was adequately, though not optimally, designed to demonstrate the differences with each type of treatment.  First, each study participant received one split-lesion treatment, with the one half of the lesion randomized to each device type, which properly controls for non-study effects (e.g. additional sun exposure).  The use of a split-face design also appropriately controls for patient variability.  However, the use of a series of multiple treatments would have magnified any possible outcome differences, and would better reflect clinical practice.   Second, one evaluation was performed photographically by a blinded assessor.  Blinding appropriately prevents bias, but the introduction of photographic artifact may obscure outcome differences.  Third, a second evaluation was performed with a skin reflectance meter, also performed by a assessor blinded to device-types used on each half.  Blinding appropriately prevents bias, but this meter has been validated for the use of evaluating erythema and pigmentation rather than portwine stains.

In this study, while both devices achieved measurable PWS lightening and no adverse events were found, the pulsed dye laser showed superior efficacy, both by blinded photographic evaluation and by blinded skin photometer.  The difference in lightening was both statistically and clinically significant (i.e. the difference in lightening was visually apparent to the blinded reviewer and the patient), even though only one treatment was performed.  As far as patient preference, 18 of 20 patients preferred to have subsequent treatments with the LPDL, while 2 preferred the IPL.

The superior results of the pulse dye laser may not be considered definitive based solely on this study, as there was no-pre-defined study hypothesis to be proven.  However, the authors refer to several other studies to underline their proposal that the LPDL be considered the first choice modality for PWS treatment, with the IPL reserved for poor-LPDL-responders.  This is an appropriate guideline.

Review of Lach E, Reduction of subcutaneous fat and improvement in cellulite appearance by dual-wavelength, low-level laser energy combined with vacuum and massage

February 15, 2009


J Cosmet Laser Ther. 2008 Dec;10(4):202-9.


Reduction of subcutaneous fat and improvement in cellulite appearance by dual-wavelength, low-level laser energy combined with vacuum and massage.


Lach E.


Boston Surgical Group, Southborough, MA 01772, USA.



In this article, Elliot Lach MD presents the first publication of the clinical results achieved with the new SmoothShapes cellulite treatment device.  Note that Lach is the inventor of the technology and a shareholder in Eleme, the company which makes the device.


In this study of 102 female patients, one thigh was randomized to treatment with the SmoothShapes device and one thigh to massage-alone.  Patients received an average of 14.3 treatments over 4 to 6 weeks.  MRI measurements, thigh circumference measurements and photographs were taken of each patient.  A patient satisfaction questionnaire was completed at the end of the study.  In SmoothShapes treated legs, MRI showed an average decrease in fat thickness of 1.19cm2 from a baseline average of 136.57cm2, which is less than 1% change.  In the control legs, MRI showed an average increase in fat thickness of 3.82cm2 from a baseline average of 133.98 cm2, about a 2% change.  The thigh circumference measurements showed no significant difference between the two SmoothShapes treatment and the control.  While photographs were taken, no grading of the photographs for severity of cellulite was presented.


While the MRI results are statistically significant, a <1% decrease in fat thickness cannot be considered clinically significant.  The increased fat thickness in the massage-only group remains unexplained.  No covariance analysis of weight gain or reduction was provided.  While the title of the article refers to “improvement in cellulite,” no evidence of any improvement in the appearance of cellulite was presented.  While patient satisfaction was reported at 72.6%, a placebo effect cannot be ruled out.  Alternatively, a quantifiable evaluation of cellulite appearance should have been easy to perform, by asking the blinded patient and/or a blinded observer to identify the leg that was treated versus the leg receiving massage only (50% correct responses would result from chance, while 100% correct responses would indicate meaningful improvement in all cases).


In summary, this study failed to show clinically significant reductions in subcutaneous fat or body circumference, nor was improvement in cellulite appearance shown.  One is left to wonder whether the device has any effect at all.


Review of Jørgensen GF, Long-pulsed dye laser versus intense pulsed light for photodamaged skin

January 30, 2009

Lasers Surg Med. 2008 Jul;40(5):293-9.

Long-pulsed dye laser versus intense pulsed light for photodamaged skin: a randomized split-face trial with blinded response evaluation.

Jørgensen GF, Hedelund L, Haedersdal M.

Department of Dermatology, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark.



In this paper, Gitte Jørgensen reports a rarely seen type of study in the aesthetic space – a randomied comparison of two competing device technologies.  The study was co-sponsored by both device manufacturers, but neither manufacturer participated in the conduct or analysis of the study.  Most aesthetic device studies compare a device treatment to an untreated control, to show that the treatment causes some effect.  In contrast, this study compared the Candela VBeam Perfecta (long pulse 595nm dye laser) with the Ellipse Flex (Intense Pulsed Light) for the treatment of photodamaged skin, to see if the treatments caused different outcomes

The study was well-designed to demonstrate the differences with each type of treatment.  First, the patient population was homogenous (light skin females).  Reduction of patient variability reduces confounding of outcomes and enables smaller sample sizes.  Second, each study participant received a series of 3 split-face treatments with the one side randomized to each device type, which properly controls for non-study effects (e.g. additional sun exposure).  The use of the series of 3 treatments would magnify outcome differences, if there were any.  Third, the evaluation was performed on-site by a blinded, independent physician, to prevent bias and to prevent the introduction of photographic artifact.  Although blinding adequately prevents bias, agreement from multiple blinded observers would be useful to reduce individual subjectivity in the assessment of improvement.

While both devices demonstrated improved outcomes in this study, the long pulse 595nm dye laser achieved overall superior results, due to superior performance on vascular lesions.  Fourteen of 20 patients obtained better clearing of telangiectasias with the pulsed dye laser and the remainder saw no difference.  The difference in lightening was both statistically and clinically significant (i.e. the difference in lightening was visually apparent to the blinded reviewer and the patient). Both devices achieved similar improvements for irregular pigmentation and skin texture.  Neither device showed any improvement in wrinkles/rhytids.  Eighteen of 20 patients preferred the pulsed dye laser, both because of improved vascular clearance and because there was less treatment-related pain.

Despite an excellent study design, there are some limitations to the study conclusions.  The superior results of the pulse dye laser should not be considered definitive, as there was no-pre-defined study hypothesis to be proven.  The study was too small to determine whether there was a significant difference in the rates of adverse effects between the two devices.  Because both devices demonstrated improvement in outcomes, practitioners may be able to achieve pulsed-dye-laser results by simply performing additional IPL treatments.  Possibly, other IPL systems may perform better than the Ellipse product used in this study.


January 29, 2009

Welcome to Aesthetic Device Review, an occasional review of notable articles on aesthetic devices from peer-reviewed publications.