A Z-shaped incision can be created in an area of high skin tension to allow skin relaxation and lengthening. A Z-plasty involves
transposing the two interdigitating flaps of skin formed by the incision.1-4 In veterinary surgery, this procedure is indicated to realign tissues, lengthen contracted scars, change the direction of
a scar, aid relaxation to allow closure of a large wound, and increase the circumference of an orifice3.
The basics of the Z-plasty technique
As a relaxing incision to aid in wound closure, the Z-plasty is especially useful for small to medium-sized skin wounds on
the distal limbs and large wounds on the trunk that are under excessive tension after primary closure. Performing a Z-plasty
avoids complications associated with second intention healing such as scarring, contracture, and poor hair growth. It is also
simpler to perform than an axial pattern flap or mesh graft and avoids the mismatched texture, thickness, and hair type that
can result from those techniques.3
Aside from relieving scar tension and relaxing contractures, Z-plasty can also be used to relieve constriction from circular
scars and strictured orifices.1,2 Specifically, it has been used to correct stenotic nares in horses5 and anal stricture following perianal fistula cryosurgery in dogs.3
Figure 1. Wide excision (18 x 32 cm) of a hemangiopericytoma from the flank and hip of this bullmastiff resulted in extensive
tension along the closure. Towel clamps were used to appose the skin while a suction drain and subcutaneous sutures were placed.
How it works
A Z-plasty is composed of a central limb and two arms of a Z-shaped incision.1,2,6 The incisions that create the central limb and arms of the Z should be of equal length since the flaps will be sutured together
after transposition. The longer the central limb length, the larger the gain in skin relaxation. Using long lengths may be
restricted by the amount of skin in the area; for instance, less skin is available on the distal limbs than on the trunk.
In addition, the tension produced with flap transposition when creating a long central limb incision may be too great to allow
Figure 2. The central limb of the Z-plasty is incised parallel to the line of tension and perpendicular to the primary wound
closure. Note that the central limb is 90 degrees to the wound, but because of the camera angle and the hip arch, the angle
may appear less than 90 degrees in the photograph.
The angles of the Z can vary from 30 to 90 degrees, with larger angles creating longer final gain in length.2,5,6 Angles of 60 degrees are most commonly used since larger angles have a tendency to produce greater tension on the surrounding
tissues.1,4,7 Angles less than 45 degrees produce narrow flaps with an insufficient blood supply.7
Figure 3. The first arm of the Z is made at a 60-degree angle from the central limb of the Z.