[Tissue expansion. Part 1: Technical and physiologic principles].

The technique of tissue expansion can now be used to prepare skin for reconstructive operations. This method has been propagated during the last 15 years, but its use has varied from great enthusiasm with exaggerated expectations to disillusion due to high complication rates. For an efficient and successful application of skin expansion an understanding of skin reactions and their control is mandatory. In this review, the biological principles of expansion, various expansion protocols and their objectives, control during the filling phase and preventive measures to avoid complications are described. For clinical use it is important that there is not one but three distinct types of expansion: an intraoperative, intermittent expansion for gentle subcutaneous skin mobilization, a short time period for expansion (between 1-2 weeks) to increase the dermal microcirculation and the "classic" prolonged period of expansion to create new skin for the reconstruction required.