With the central limb and two arms of the Z of equal length and each angle at 60 degrees, theoretically, the length of the
Z should increase 75%.4,6,7 Because of differences in skin elasticity and modification of the defect location, the actual increase in length is less
than predicted.4,8,9 Therefore, a Z-plasty with 60-degree arms will actually produce a total increase in length of 41% to 63%.9
Figure 4. Both arms of the Z have about the same length as the central limb.
Z-plasty is a convenient method of closing high-tension wounds (see the boxed text titled "The basics of the Z-plasty technique"); however, its use is limited to specific cases. The area of surgery must have some laxity perpendicular to the line of tension
to allow rotation of the Z flaps. Scarring or fibrosis that might limit the amount of skin elasticity in the region will make
flap transposition difficult.2 When performing a Z-plasty, careful planning of the placement of the Z incision is needed. The region around the original
defect must be manipulated to locate an area with an adequate amount of skin. Keep in mind that the principle of using a Z-plasty
as a relaxing incision is moving skin from one site where it is readily available into another where it is needed to relieve
tension.6 The health of the adjacent skin must be taken into account since the transposed flaps need to have an adequate blood supply.3 The base of a Z-plasty flap should not contain scar tissue, which could impair blood supply to the flap. Z-plasties can be
performed before wound closure to relieve skin tension during apposition or after wound closure if excessive tension at the
closure site is noted.
Figure 5. The flaps are elevated with subcutaneous dissection.
The technique and outcome
The most concise method of forming the Z is by using a precut, sterile template before incising. Radiographic film has proved
to be an acceptable material because of its ease of cutting to form and its ability to conform to surfaces yet retain its
shape. The radiographic film is gas-sterilized with ethylene oxide. Alternatively, the Z can be approximated by sight, marked
with a sterile pen, and then incised. A full-thickness skin incision should be made to facilitate better flap rotation.9
Figure 6. Once the subcutaneous tissues have been dissected, the elevated flap tips begin to transpose as the Z incision is
lengthened by tension from the original wound closure.
When using an adjacent Z-plasty to reduce tension on an existing traumatic wound or tumor excision site (Figure 1), place the central limb of the Z perpendicular to the long axis of the wound and thus parallel to the line of tension (Figure 2). Create the arms at a 60-degree angle from the central limb (Figure 3). The central limb and arms of the Z should be of equal length (Figure 4). When the flaps are transposed, the central limb will rotate 90 degrees to be parallel to the original wound, and the area
of the central limb will be lengthened while its width will be decreased. This allows more skin flexibility to close the original
Figure 7. The flaps are further transposed.