The oblong parallelogram-shaped "Schwenklappen"-plasty.

An attempt is made to analyze the general criteria for the Schwenklappen-plasty and to make them accessible to practical application. The preferred basic form is the oblong parallelogram, which allows an exact assessment of the new tension situation that arises as a result of the defect closure and the amount of the skin reserve needed. Schwenklappen designed in the shape of oblong parallelograms generally distribute the arising tension equally to the farther surroundings of the defect. Therefore, they require a smaller skin supply in the area adjacent to the defect than do rhomboid Schwenklappen. The approaches necessary to make optimal use of the available skin reserves are described. They relate especially to the position of a defect in relation to the relaxed skin tension lines and to the adjustment of a Schwenklappen-plasty to the maximal skin available. Also discussed are the geometry and mechanics of planimetric Schwenklappen, stereometric local flaps, and the covering of circular defects by oblong Schwenklappen.