Selective photothermolysis in skin by using subcutaneous optical fibers

Vascular selective photothermolysis has been shown to be effective in treating hypertrophic scars. Performing selective photothermolysis on the vasculature deep within thick scars requires new methods for delivering laser energy. It is the objective of this study to model the use of subcutaneous fiber optics to perform selective photothermolysis in skin as a possible aid in the treatment of thick scars.

A Monte Carlo simulation was performed to study the expected region of vascular necrosis in a two layer skin model when 585-nm radiation is delivered into the dermis by means of subcutaneous optical fibers.

The extent of vascular necrosis is independent of fiber diameter for a fixed total energy. A fiber penetrating barely below the epidermis decreases the maximum epidermal fluence by more than an order of magnitude relative to a superficial beam. Using four fibers simultaneously can significantly increase the depth of vascular necrosis.

Small diameter fibers are optimum if the maximum fluence tolerable in the dermis is not a limiting factor. Shallowly inserted fibers can significantly decrease epidermal damage to dark-skinned patients undergoing laser therapy.