Deutschland – Regensburg – Klinische Studie > Langfristige Wirksamkeit des Diodenlasers für Epilation
Long-term efficacy of a high power diode laser for hair removal
Introduction
- Many patients complain of problems regarding excess hair growth such as hirsutism and hypertrichosis
- In the last few years the technology of laser assisted hair removal is advancing rapidly using ruby laser (694 nm), alexandrite laser (755 nm) or diode laser (810 nm)
Aim of the Study
To investigate the longterm efficacy of a high power diode laser forhair removal:
- Volunteers (study I) and patients using a spotsize of 8 mm
- Volunteers (study II) using an enlarged spotsize of 12 mm
Figure 1: Absorption of melanin at three differentwavelengths normalized to 694 nm (ruby laser)
Methods
- Laser therapy was performed using a high power diode laser (810 nm)
- The number of re-growing hair was counted four weeks and three months after the last laser treatment
- The ratio of hairs in the treated area to an untreated area nearby, which served as control, was referred toas re-growth
- Punch biopsies for histological evaluation of hair follicles were taken 24 h after laser treatment
Study I
- Pulse duration up to 50 ms,spotsize 8 mm
- Fluence up to 44 J/cm2
- Forty consenting volunteerswere treated three times onthe lower or upper legs atregular time intervals of two tothree weeks
- Skin types I–III
Other treatment sites
- Pulse duration up to 50 ms,spotsize 8 mm
- Fluence up to 44 J/cm2
- Patients were treated atdifferent sites
- Regular treatment intervals oftwo to three weeks
- Skin types I–III
Study II
- Pulse duration up to 60 ms,spotsize 12 mm
- Fluence up to 40 J/cm2
- Twenty consentingvolunteers were treated threetimes on the lower or upperlegs at regular time intervalsof two to three weeks
- Skin types I–III
To avoid side-effects the skin was cooled directlybefore laser treatment using a cooling device
Wolfgang Bäumler, Ph.D., Sabine Neff M.D.,Michael Landthaler,
M.D. & Rolf-Markus Szeimies, M.D.
Department of Dermatology, University of Regensburg, D-93042 Regensburg, Germany
Results study I
Figure 2: Upper leg of a volunteer before laser treatment (A) and 4 weeks (B)after the third treatment (8 mm spotsize, 44 J/cm2)
Figure 3: Efficacy of laser-assisted hair removal using thediode laser 4 weeks and 3 month after the third lasertreatment
Results at other treatment sites
Figure 4: The chin of a female patient before laser treatment (A) and 8 weeks (B)after the third laser treatment (8mm spotsize, 36 J/cm2)
Figure 5: Bikini site of a female patient before laser treatment (A) and 8 weeks (B)after the third laser treatment (8mm spotsize, 36 J/cm≈)
Results study II
Figure 6: Upper leg of a volunteer 4 weeks after the third treatment (12 mm spotsize, 40 J/cm2)
Figure 8: Efficacy of laser-assisted hair removal using thediode laser 4 weeks and 3 month after the third lasertreatment
Figure 7: Histologyshowed that thestructure of hairs wassignificantly altered.Thehair shafts showedfragmentation. Thefollicular epithelium wasruptured (arrow),homogenized and thesurrounding areashowed a denseinflammatory infiltrateconsisting of neutrophilgranulocytes. Theepidermis remainedunaltered (HE-staining)
Conclusion
- The results provide evidence for an effective and long-lasting growth delay of hairs using a high power diodelaser
- As immediate response to laser treatment perifollicular erythema and edema were seen but no severe side-effects such as scar formation or permanent pigmentary changes
- The use of 12 mm spotsize significantly improved the growth delay of hair measured 4 weeks after treatment
- Studies now should be performed to determine the treatment interval for maximal efficacy of laser assistedhair removal using a high power diode laser
