Thesis (Ph.D.) - Cairo University - National Institute of Laser Enhanced Sciences- Department of Laser Applications in Medical

Striae distensae are common undesirable skin lesions of significant aesthetic concern. To compare the efficacy of two fluences (75 and 100 J/ cm²) of long pulsed Nd:YAG laser in the treatment of striae. Forty five patients (Fitzpatrick skin types III{u2013}V) aged between 16 and 36 years with striae (23 patients with rubra type and 22 with alba type) were enrolled in the study. Each stria was divided into three equal sections, whereby the outer sections were treated with longpulsed 1064 nm Nd:YAG laser, at a fluence of 75 or 100 J/ cm², and fixed laser settings of 5 mm spot size and 15 ms pulse duration. The middle section was an untreated control. All subjects received four treatments at 3 weeks interval. Three 2-mm punch biopsies were taken from six subjects, all of the same stria, one before treatment and the other two from the outer sections, 3 months after the last session. Paraffin-embedded skin sections were subjected to histological and quantitative morphometric studies for collagen and elastic fibres. Results were assessed clinically through photographic evaluation and were considered satisfactory for both doctors and patients. A significant improvement in appearance of striae alba using 100 J/cm² was found while striae rubra improved more with 75J/ cm². Histologically, collagen and elastin fibres increased in posttreatment samples. A satisfactory improvement in striae distensae lesions was seen through clinical and histological evaluation. Thus, long-pulsed Nd:YAG laser is a safe and effective module of laser treatment for these common skin lesion

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