Application and effect of new hair removal laser

Laser hair removal has attracted much attention because of its convenient operation, relatively non-invasive to other surrounding skin tissues and less adverse reactions. Since it has been widely used in clinic, a large number of research data show that the lasting hair removal effect is closely related to the color of hair and the number of treatments. However, the ideal parameters, methods, safety and effectiveness of laser therapy need to be further studied. Let’s take a look at the application and effect of the following new hair removal lasers.

1、 Long pulse ruby laser (LP ruby, 694 nm)

It is suitable for light skinned individuals (firzpatrick I and type I). It has specificity in destroying hair follicles, but the ruby laser transmits pulses slowly, which is not practical in the treatment of large areas. Gault et al. A conducted an 18 month long pulse ruby laser treatment study on 116 patients with poor previous efficacy. The average follow-up time was 23.25 weeks. After an average of 1.92 treatments, the hair density decreased by 56.400. There was statistically significant difference before and after treatment (paired t-test PG 0.00001) O somcner et al. 9 reported the efficacy of long pulse ruby laser in 43 patients with firzpatrick type I ~ n. Pulse width 950 l}s, spot size 4 mm, average flow 48 J / CTRI. The first point of each patient was treated only once, and the second point was treated 4 times a month. After one treatment, the hair count decreased to 4600 in one month, but increased to 8000 in the third month and 66000 in the sixth month. After three treatments, the hair count decreased to 2900 in one month. At the same point, the hair count increased to 4400 3 months after 4 treatments. This therapy is well tolerated by patients, and large flow continuous treatment is easy to tolerate. After the first treatment, 60% of the patients had mild temporary erythema and papules, 14% had water scars and 33% had small infatuation. Based on the above evidence, long pulse ruby laser is easy to tolerate. In order to obtain continuous therapeutic effect, multiple treatments can increase the clinical efficacy for at least 6 months.

2、 Long pulse alexandrite laser (LP Alexandrite, 755nm)

Compared with ruby laser, it penetrates deeper into the dermis and is less likely to be absorbed by epidermal melanin. In theory, it is safer to use it for darker skin color. Bou second class IO studied the treatment of 58 areas of 23 patients with fir}patrick ill ~ n with long pulse alexandrite laser. Wavelength 755nm, flow 17 ~ 25) i}, spot size 10mm. The patients were divided into 4 groups according to the number of treatment: group I = 4, group II = 5, group III = 6, and group n: the treatment was successful if the hair count of wife 70 was reduced by 50% and there were no side effects. The results showed that the decrease of hair count was positively correlated with the number of treatment (r = 0.402, pg0.005). Side effects: pigmentation (2 cases in group n), hypopigmentation (1 case in group n), water scar (1 case in group n), folliculitis (1 case in group III and 1 case in group n). The treatment success rate of the total area was 48.300 (28; 58). The treatment success rates of each group were 2500 in group I, 760 in group ll, 5800 in group III and 150O in group n (P = 0.002). Conclusion: multiple treatments can obtain higher hair reduction rate with higher incidence of side effects. Clinical application should seek a balance between the two. Xi Dan and others treated 424 patients with hairy face, trunk and limbs with alexandrite long pulse laser. The wavelength was 755 nm, the pulse width was 20 ms, the spot diameter was 7 ~ 10, the treatment energy was 15 ~ 25 J icm{and the treatment interval was 3 months. Results: the one-time depilation rate of axillary and limbs was about 300 o, and the two-time depilation rate was about 5500, which was energy dependent. It was found that all cases had delayed hair growth, of which 55.4% had hair thinning without any side effects.

3、 Pulsed diode (800 nm)

This wavelength is not absorbed as much as the first two, so it is safe and effective for people with darker skin color and beard pseudofolliculitis, but there may be pigmentation or hypopigmentation. Li Xueli observed the efficacy of Lightsheer semiconductor laser hair removal treatment. Methods: 90 patients with hirsutism were treated with semiconductor laser. Wavelength 800 NTN, pulse width 5-100 MS, energy density 10-60) / CTRI, routine skin preparation in the hair removal treatment area before operation. The pulse width of 100 ms and energy of 28 ~ 35 J / cm {are suitable for treatment. Generally, the treatment starts from low energy, and the treatment interval is about 1 ~ 3 months according to the body arrest time of different parts of hair. Results: 90 patients were followed up for 12 months, and no adverse reactions such as addiction mark and chromatin deposition occurred.

4、 Aluminum doped garnet laser (Nd: yac31064nm)

Battle et al. “Pointed out that this wavelength is a safe and effective method for the treatment of patients with darker complexion. The expected results can be achieved through conservative flow, long pulse width and multiple treatments.

5、 Pulsed high intensity light source system (LPL sources, 590-1200)

During treatment, the emitted light is filtered through a series of “filters”, and the selected wavelength can be suitable for the skin type and color of a specific individual. Dierickx reported}z that 12 weeks after one treatment, hair loss was about 5000 -‘6000; After repeated treatment (3-4 times) and follow-up for at least 6 months, the number of hair was reduced by 750002.4. Adverse reactions of laser hair removal (1) there may be slight pain during treatment, and local anesthesia is generally not required. (2) Erythema and follicular edema may occur immediately in the treatment area and usually subside spontaneously within a few hours. (3) Purple pain may appear in the treatment area of individual patients 1 ~ 3 days after treatment. (4) after treatment, water scars and superficial skin erosion may appear in the treatment area. (5) slight temporary hypopigmentation or deepening of pigment may occur, and most of them subside spontaneously within one month. The longer the wavelength of ~zpatrick laser, the lower the incidence of adverse reactions.