Michael Drosner’s research while affiliated with Technical University of Munich and other places

To evaluate the efficacy and safety of a thermal mode Erbium:YAG laser several in-vivo morphological as well as clinical changes were monitored in a multi-center investigation. An Erbium:YAG laser was used at a thermal mode with sub-ablative fluences of 2.1 and 3.1 J/cm(2) with parallel air cooling to treat either periorbital, perioral rhytides or patients with post-traumatic or acne scars. Two treatments were applied 2 months apart, with follow-up at 1, 3, 6, and 12 months post-treatment. Photographs were taken before and at each follow-up visit and evaluated by three blinded independent reviewers. Histology and immunohistochemistry for pro-collagen expression were investigated. Optical coherence tomography (OCT) was performed before, and at 4, 14, and 28 days after single pass treatment with Erbium:YAG thermal pulses. The improvement of rhytides at 1-3 months follow-up was graded as excellent in 19%, good in 19%, fair in 31%, and no improvement in 31%. At the 6- to 12-month follow-up, the improvement was excellent in 40%, good in 40%, fair in 20%, and no improvement in 0%. The improvement of scars at 3-6 months follow-up was graded as excellent in 50%, good in 25%, fair in 25%, and no improvement in 0%. Intra- and post-operative discomfort was described as mild by the patients. OCT, histological sections and immunohistochemistry demonstrated production of new collagen bundles. Thermal Erbium:YAG pulses can induce collagen neogenesis, as proved by temperature elevation and morphological changes in the upper dermis. This leads clinically to visible and long lasting reduction of wrinkles and scars after applying multiple passes with minimal side-effects.

Objective The degree of reproducibility and precision of the mechanical direct profilometry and the intra- and interindividual fluctuations of 7 surface parameters were investigated. Material and methods Negative replicas were sampled from defined areas of the skin of 31 volunteers an evaluated with the profile-tracking device TKC 300 Hommeltester in order to derive data about the inter- and intraindividual fluctuations. To determine the precision of this method 6 roughness parameters and J of waviness of each replica were repetitively evaluated. The practicability was tested introducing minimal changes in the experimental set-up. Further, the effect of urea-containing creme on the skins topography was investigated in a double-blind clinical setting on a collective of 11 patients. Results The precision of this method is shown by nearly unchanged topographic parameters. Moreover, our data show smaller intra- than interindividual fluctuations of roughness (Ra) and waviness (Wt), being an important demand for clinical investigations. Conclusion In this paper we demonstrate that the parameters of both roughness as well as the recently introduced waviness can be conveniently evaluated with a high degree of precision with the direct profilometry.