Z-plasty

Introduction

A Z-plasty is used to accomplish one or more of three changes in the nature of a scar:

• change of scar direction,
• interruption of scar linearity,
• and release of scar contracture (lengthening of scar).

Z-plasty should be considered when it is optimal to change the direction of a scar so that a portion of it is more easily concealed either within relaxed skin tension lines (RSTLs) or in a border between facial aesthetic regions. Similarly, with Z-plasty, a long straight scar may be divided into smaller irregular segments to allow better scar camouflage. Scars that cause distortion of facial features secondary to contracture may be lengthened with Z-plasty techniques, correcting or improving the distortion. As with other methods of scar revision that interrupt a straight scar, the scar resulting from Z-plasty will counter forces of scar contracture. This is because of the very nature of the Z-shaped scar that occurs from Z-plasty. Each segment of the Z contracts in a different direction. Z-plasty is particularly useful in treating contracted or webbed scars and scars that distort anatomic facial landmarks. A main advantage of Z-plasty over other techniques, such as W-plasty, is that it does not require skin excision for the procedure to be performed.

For optimal results, many situations require a combination of scar revision techniques, such as W-plasty or geometric broken-line closure, in addition to Z-plasty.

Geometry and design

The classic description of Z-plasty consists of a design in which the central limb and two peripheral limbs are in the shape of a Z such that two triangle-shaped flaps of equal size are created. All three limbs are of identical length, and the central limb consists of the scar that is to be lengthened or realigned.

Transposition of the triangular flaps of standard 60° Z-plasty results in the following changes:

• the axis of the central limb is rotated 90° (in the example, a vertical scar is changed to a horizontal orientation);
• the distance between the points labeled B and C of the original central limb is increased;
• and the final scar is changed from a straight line to a nonlinear Z configuration.

Although a 60° Z-plasty is perhaps the most common design, angles between 30° and 90° are possible. Changing the angle of the flaps will cause a change in the length gained in the axis of the original central limb.

Z-plasty皮瓣侧臂和中心臂之间的角度和瘢痕松解程度之间的关系
Changing the angle of the flaps will cause a change in the length gained in the axis of the original central limb. Theoretically, the percentage gain in length increases with larger angles. However, the amount of lengthening noted in actual practice is usually less than caculated.

Z-plasty皮瓣角度和center limb瘢痕旋转角度之间的关系
The degree of directional change of the central limb of the Z-plasty is also variable. In the 60° Z-plasty, the orientation of the central limb is changed 90° from its original orientation. In the 45° Z-plasty, the orientation of the central limb is changed approximately 60° from its original position. In the 30° Z-plasty, the change is approximately 45°. This relationship between the angle of the Z-plasty and the change in orientation of the central limb of the Z-plasty is an extremely important consideration in planning of Z-plasty.

Z-plasty皮瓣limb长度和松解程度之间的关系
The initial length of the central limb affects the final outcome of Z-plasty. As the central limb of the Z is increased in length, so too is the gain in linear length between the points marking the ends of the central limb. Unfortunately, as the three limbs of the Z-plasty become longer, there is also a greater likelihood of a more apparent scar. Multiple Z-plasties with shorter limbs to replace a single large Z-plasty with long limbs can circumvent this problem. A single large 60° Z-plasty provides more gain in length than multiple small 60° Z-plasties along the same central limb. However, the aesthetic consequences and tissue availability for construction of the Z-plasty flaps often preclude the use of a single, large Z-plasty. On the face, limb length is usually limited to 1 cm or less. On the neck, limb length should not exceed 2 cm.

除了长度和角度之外的变化

• Four-flap Z-plasty

This technique increases the gain in length of the central limb by using four triangular flaps that are interposed between each other. A 90° Z-plasty is first designed, and then the 90° angle is bisected to design two 45° triangular flaps that are transposed (Fig. 14-5). Even greater gain in length of the central limb of a Z-plasty can be obtained by using 120° angles, which subsequently are bisected into four 60° flaps (Fig. 14-6). There are a number of variations on this theme, including a six-flap Z-plasty. However, the greater the number of flaps created, the greater is the total number of limbs and thus scars and the greater is the number of standing cutaneous deformities that develop when the flaps are transposed.

• Z-plasty having unequal angles

In such situations, the flap with the more acute angle is pivoted in a greater arc than that of the larger angled flap. Minimal gain in length of the central limb will occur with unequal-angled Z-plasties. The main purpose of such designs is to transpose skin of the smaller angled flap to a more desirable location.

Surgical application and technique

The discussion to this point has involved theoretical concerns about the classic geometry of Z-plasty. An understanding of the classic design is critical, but practical clinical considerations are even more important. A number of studies have shown that the increase is considerably less in the clinical situation compared with the calculated gain. Similarly, there is a limit to the angles of the Z-plasty flaps that may be useful. Z-plasties less than 30° generally should not be used because of concern for vascularity of the narrow triangular flaps created by these acute angles. In the design of acutely angulated flaps, the width of the flap may be broadened by curving the limbs of the flap. Conversely, triangular flaps with angles greater than 75° will commonly produce standing cutaneous deformities that require excision. Thus, such large angled Z-plasties should be avoided whenever possible.

In designing a Z-plasty, evaluation of the surrounding skin and facial structures is necessary.

• Skin laxity at the base of each triangular flap of the Z-plasty must be adequate to allow proper pivotal movement of the flaps.
• If a facial structure such as the eyelid, oral commissure, lip, or nasal ala is in proximity of the Z-plasty, distortion of these structures may occur.
• It is also important to assess the degree of scar tissue in the central limb of the Z. The scar must be adequately resected or released to reduce resistance to transposition of the Z-plasty flaps. Accordingly, it is essential to release and commonly to remove subcutaneous scar tissue.

A 60° Z-plasty will reposition the central limb 90°; more acutely angled Z-plasties will position the central limb less than this. An understanding of this concept will assist in proper positioning of Z-plasty limbs in relation to RSTLs. To reposition the central limb of a Z-plasty in RSTLs, the angles of the Z should be calculated accordingly. With scars located approximately 90° to RSTLs, a 60° Z-plasty is required to reposition the central limb parallel to RSTLs. As the axis of a scar in relationship to RSTLs becomes more acute, Z-plasty angles should become more acute to position the central limb and the two peripheral limb scars as parallel as possible to RSTLs. For scars less than 30° to RSTLs, Z-plasty may not be necessary for scar realignment.

侧臂位置的选择
central limb和peripheral limb形成的瘢痕与RSTLs或美容区分界线的关系是选择的主要依据。

• To perform a Z-plasty, the design is marked on the skin before injection of local anesthetic to avoid distortion of
• In cases in which the scar is wide, it is occasionally useful to temporarily suture the wound together to facilitate the design of the peripheral limbs of the Z-plasty.
• Because of skin retraction after release of the central limb scar, there is a tendency to incise the tips of the Z-plasty flaps such that they become overly narrowed. This tendency can be countered by slightly rounding and widening the incision where the peripheral limb joins the central limb of the Z-plasty.
• Conversely, the peripheral limbs may be incised before the central limb is.
• The flaps are sutured in place beginning with placement of several subcutaneous sutures made of an absorbable material. However, the number of sutures should be limited so as not to compromise the vascularity of the flaps.
• Skin incisions are closed with fine (5-0 or 6-0) suture material by meticulous, atraumatic, woundeverting techniques. Cutaneous sutures are removed 3 to 5 days postoperatively.

Summary

Z-plasty is one of the oldest concepts in plastic surgery and remains a prevalent and important technique. An understanding of its geometric principles is critical to its successful application. Z-plasty is a double transposition flap technique that is used to lengthen contracted scars, to change the orientation of scars for better alignment with RSTLs, or to interrupt straight scars for better camouflage. Z-plasty is also helpful in the repair of some cutaneous defects and for realignment of malpositioned Z-plasty is one of the oldest concepts in plastic surgeryand remains a prevalent and important technique. An understanding of its geometric principles is critical to its successful application. Z-plasty is a double transposition flap technique that is used to lengthen contracted scars, to change the orientation of scars for better alignment with RSTLs, or to interrupt straight scars for better camouflage. Z-plasty is also helpful in the repair of some cutaneous defects and for realignment of malpositioned. Z-plasty is also helpful in the repair of a primary cleft palate. It is impossible to list all of the reported uses of Z-plasty described in the literature. Suffice to say that with a thorough understanding of its principles, Z-plasty is an extremely powerful tool in the reconstructive surgeon’s armamentarium.