Z-plasty

Z-plasty is a surgical technique that is used in plastic surgery to change the direction of a preexisting scar in order for it to be hidden within the natural creases of the skin. Z-plasty is also used to relieve skin tension occurring as a result of contracture of a scar. The technique is especially useful for revising unsightly scars on the face and for releasing scarring across joints, such as on the fingers or in the armpits, that may restrict normal movement or cause deformity.

Z-plasty in detail - technical

It is also known as: Compound Z-plasty; Double transposition flaps; Double-opposing Z-plasty; Four-flap Z-plasty; Scar revision

Definition

Z-plasty is a simple yet powerful plastic surgery technique involving the creation and transposition of two identical triangular tissue flaps.

Purpose

Z-plasty is commonly used for scar revision, with the purposes of lengthening, reorienting, and/or camouflaging the scar. This allows the new scar to be more appropriately concealed within relaxed skin tension lines or between facial anatomical subunits (see also: Dynamic Facial Lines, Langer’s Line, Relaxed Skin Tension Lines). Furthermore, the creation of the Z-plasty segments allows countering of the existing scar contractile forces (see also: Hypertrophic Scar, Keloid). When used appropriately, Z-plasty can provide significant aesthetic improvement of the existing scar (Papel 2009).

Principle

History and Origin

The technique has undergone significant evolution and a number of modifications to come to exist in the form as we know today. Although the exact date of origin is uncertain, first mentioning of the technique is attributed to multiple authors including Denonvilliers, Seres, and Szymanowski in the 1800s. McCurdy’s description of a Z-shaped incision with flap elevation in the early 1900s brought awareness to the technique in the American literature. Other authors including Berger and Limberg provided further refinement to the technique through their published works in the mid-1900s (Rohrich and Zbar 1999).

The Classical Z-plasty Procedure

Though seemingly simple, a thorough understanding of the classical Z-plasty geometry is critical. The traditional standard Z-plasty is created with two transposing triangular skin flaps using an angle of 60, and is the cornerstone scar revision technique by which other scar revision procedures as well as Z-plasty variations are measured against (Thorne et al. 2007). The surgical site is first cleaned and degreased with an alcohol pad or other degreasing agents, and the planned incisions are drawn with a fine-tip surgical marker. This is done prior to infiltration of local anesthetics and vasoconstriction agents to avoid tissue distortion secondary to the injection.

The design of the classical Z-plasty consists of a central incision and two adjacent limbs that form equal 60 angles with the central incision. The lateral limbs can be designed such that they form in either a true Z or a reverse Z. Depending on the anatomical location of the scar and the anticipated final distortion of the nearby soft tissue, usually one design is more favorable than the other. The three incisions are of equal length to allow ease in transposing the flaps. The central incision generally lies within the existing scar, and often the scar can be excised via fusiform excision with the resulting defect forming the central limb. To simplify the design of a 60 angle flap, a 90 angle flap can be marked and visually divided into thirds, and a 60 angle flap hence would occupy two-thirds of the 90 angle flap.

After completion of the markings, the surgical site is infiltrated with a local anesthetic mixed with a vasoconstriction agent (e.g., 1% lidocaine with 1:100,000 epinephrine) for anesthesia and vasoconstriction. Care is taken to not smudge the ink by injecting adjacent to, but not through, the markings. Generally the procedure can be carried out with local anesthetics alone. However, conscious sedation or general anesthesia can be considered per patient request or if other more extensive adjunct procedures are planned concurrently (see also: ▶Anesthetic Techniques for Otolaryngologic Patient, Sedation). The surgical site is then lightly prepped with an antibacterial solution (e.g., betadine or chlorhexidine solution) and sterilely draped. The eye should be adequately protected if working in the periocular area.

If the central limb scar is to be excised via fusiform excision, this is completed first. Incisions are then made through the skin along the two adjacent limbs with either a No. 15 or No. 15C blade, depending on surgeon preference, until the subcutaneous fat layer is reached. The incisions are beveled outward just slightly to maximize wound eversion on closing. Full-thickness triangular skin flaps are then raised. The flaps need to at least contain full-thickness skin to maximize flap viability and counter wound contracture. However, increasing flap thickness will also hinder the ease by which the flaps can be transposed. The ideal plane for flap elevation hence lies between the subdermal plexus layer and the subcutaneous fat. As the dissection progresses the tissue flaps are gently retracted with single or narrow double-prong skin hooks to minimize trauma to the tissue, particularly the apex of the flaps. Wide undermining beneath the dermis and within the layer of subcutaneous fat of the adjacent soft tissue is critical to achieve adequate mobilization of the skin flaps and minimize tension on wound closure. For the classical Z-plasty the two flaps are of the same size and shape.

The two adjacent triangular flaps are then advanced and rotated in place (Fig. 1). Hemostasis is achieved with bipolar cautery and the flaps are then temporarily held in place with anchoring sutures. If undue tension is noted additional undermining may be necessary to gain additional mobility of the flaps. If a small standing cone deformity exists, this can usually be addressed by either equalizing wound edges with sutures during flap inset or limited tissue trimming. The incisions are then closed in layers with 4-0 or 5-0 Vicryl subcutaneous sutures and interrupted 5-0 or 6-0 Prolene cutaneous sutures. Avoiding suturing directly through the apex of the flaps will decrease the likelihood of dehiscence near the tip, particularly in narrow-angled flaps. Topical ointment such as Bacitracin is applied and incisions are then dressed with a nonadhesive dressing such as Telfa and secured with tape or Steri-Strips. Depending on the anatomical area the sutures can generally be removed in 4–7 days. Patients are instructed on appropriate wound care including keeping the incisions clean and moisturized. Prophylactic antibiotics postoperatively generally are not necessary in the face/neck region given the inherent rich vascularity of these areas. However, special consideration may be given to the immunocompromised population including patients with diabetes or a history of head and neck radiation (Baker 2007) (see also: ▶Preoperative Evaluation/Testing of Otolaryngologic Patient, Postoperative Management, Radiation Late Effects).

The classical 60 Z-plasty theoretically lengthens the scar by 75% and reorients the central limb (usually the scar to be revised) by 90. Z-plasty designs with angles between 30 and 90 are theoretically possible. The magnitude of scar lengthening is directly proportional to the angles by which the flaps are designed, and the lengthening is along the axis of the original central limb. Every 15 increase in angle roughly correlates with a 25% gain in length. Therefore, a 45 Z-plasty is expected to yield approximately a 50% increase in length while a 30 Z-plasty would be expected to yield approximately a 25% increase in length. The amount of reorientation similarly varies. While the central limb is expected to reorient by approximately 90 in a 60 Z-plasty, a 45 Z-plasty can be expected to reorient the scar by approximately 60 and a 30 Z-plasty reorient by approximately 45 (Fig. 2) (Papel 2009).

In practice, however, one can expect the extent of lengthening and reorientation to be less secondary to existing surrounding tissue tension and scar contracture. The actual amount of lengthening, for example, has been predicted to range from 16% to 45% less than predicted based on mathematical modeling. As the angles of the Z-plasty become more acute, the blood supply to the flaps, particularly near the apex, becomes more tenuous. One method to counter this in situations where acutely angled flaps are required is to curve the flap limbs hence broadening the apex of the flaps. In contrast, as the angles become more obtuse and the flaps become more broadly based, the amount of flap rotation necessary for proper inset is increased, resulting in increased tension on wound closure and higher risk for wound dehiscence. Furthermore, there is increased chance for cutaneous standing cone deformity near the base as the angles widen, which may require additional trimming or excision (Rohrich and Zbar 1999).

Design Considerations

Proper planning of Z-plasty, as with any surgical procedure, is of utmost importance. For the novice surgeon, taking the time before surgery to draw and mentally plan the procedure on paper can prevent unnecessary intraoperative blunders and improve the final surgical outcome. Of course, depending on the anatomical location and size of the flaps, the amount of adjacent skin tensionwill differ. Hence, the surrounding tissue quality will first need to be assessed. In order for adequatemobilization of the flaps to occur, sufficient undermining of the surrounding tissue is warranted.

Depending on the severity of surrounding soft tissue contraction, further undermining and resection of a severely contracted scar may be necessary to achieve sufficient tissue mobility for tissue transposition to take place. Secondly, the location of the scar in relation to the surrounding structures needs to be assessed. Its proximity to structures such as eyelids, nasal ala, lip, and other functionally important structures needs to be noted. In addition to reorienting the scar to within the relaxed skin tension lines as mentioned above, boundaries between facial aesthetic subunits also present as opportunities for scar reorientation and require understanding of the subunit principle. Depending on the goal and objective of what is to be accomplished, Z-plasty may not always be the appropriate scar revision procedure and the astute surgeon will recognize this prior to committing to the scalpel. For instance, as discussed previously the amount of reorientation decreases with a more acute angle design of the Z-plasty, with a 30 angle Z-plasty theoretically yielding a 45 reorientation. Although a more acutely angled Z-plasty is possible, the vascular supply to the flaps is likely to be more compromised and flap survival may be in jeopardy. Therefore, if the amount of desired reorientation is less than 30–45, Z-plasty may not be the appropriate procedure and alternative approaches such as simple fusiform excision to realign the scar may be more appropriate (Hove et al. 2001).

Variations

The design of the classical Z-plasty is such that the three limbs are equal in length. However, as the central limb or the scar in question increases in length, this translates into a Z-plasty with longer limbs and more apparent additional scars. In the head and neck region the limited surface area often precludes the possibility of designing a Z-plasty with limbs longer than 2–3 cm in length. Furthermore, a single Z-plasty with longer limbs, hence larger triangular flaps, can result in increased distortion of adjacent aesthetic subunits, particularly in the face. One solution to this challenge is the use of multiple Z-plasties in series with shorter limbs, also known as a compound Z-plasty, most commonly designed with 60 angles. The multiple Z-plasties in series provides less gain in length compared to a single Z-plasty with longer limbs, and this is secondary to the field of tension exerted by the multiple lateral limbs on each other. However, this allows camouflaging of the final scar by breaking up a straight line scar through the use of multiple short adjacent limbs.

It is also possible to significantly increase the amount of central limb lengthening without increasing the length of the adjacent limbs, although this does require the creation of more limbs and hence more flaps. Both four-flap and six-flap Z-plasties have been described in the literature as a means to achieve this. For the four-flap Z-plasty, a 90 or 120 Z-plasty can be designed and the angles bisected, creating four transposition flaps, each of 45 or 60 angles. Another variation of the four-flap Z-plasty is the double-opposing Z-plasties where two Z-plasties, usually at 45 or 60 angles, are designed as adjoining mirror images of each other. However, with the increased number of flaps there is increased risk for compromised vascularity to the flaps as well as more apparent scars. Nevertheless, the multiple-flap Z-plasty variation is a powerful tool in a plastic surgeon’s armamentarium to achieve significant tension release in severely contracted scars in areas with limited adjacent skin availability for tissue transfer (e.g., medial canthal area).

Finally, if tissue transposition is the primary goal but no significant lengthening is warranted, Z-plasty with unequal triangles can be considered. Rather than creating two triangular flaps of equal size, one flap is usually created with a limb perpendicular to the central limb resulting in a 90 flap. The other flap is usually a smaller flap ranging from 30 to 60. The resulting gain in length is directly proportional to the size of the smaller flap. Sometimes referred to as a “half Z-plasty,” this variation is particularly useful in blending the edges of a broad area of scar tissue (e.g., burn scar) with adjacent normal tissue (Hudson 2000).

Indications for Z-plasty

Indications for Z-plasty include unfavorable scars that cross anatomical subunits or lie counter to the direction of relaxed skin tension lines. Multiple Z-plasties can be performed to release undue tension in contracted scars. The technique can be performed in isolation or in conjunction with other scar revision techniques to achieve optimal aesthetic outcome (Thorne et al. 2007; Papel 2009) (see also: ▶Axial Flaps, ▶Fasciocutaneous Flaps, ▶Classification of Flaps, Flaps, ▶Local Flaps, ▶Pedicled Flaps, ▶Perforator Flaps, ▶Random Flaps, ▶Regional Flaps, ▶Rotational Flaps).

Contraindications

Patients on anticoagulants (e.g., aspirin, clopidogrel, certain herbal medications, and nutritional supplements) should be advised to stop taking themedication 5–7 days prior to the procedure if possible. Although not an absolute contraindication, patients unable to discontinue the anticoagulation regimen prior need to be counseled appropriately of increasing bleeding risk postoperatively and particularly attention needs to be paid to hemostasis intraoperatively. Pressure dressing can also be considered postoperatively in these patients (see also: ▶Preoperative Evaluation/Testing of Otolaryngologic Patient, Postoperative Management).

Considerations should be given to performing Z-plasties on facial areas where distortions secondary to tissue rearrangement may cause undesirable functional or aesthetic outcomes (e.g., upper/lower eyelids, nasal ala, and oral commissure). Achieving satisfactory outcomes in these areas may require variations of the technique and/or adjunctive procedures (Baker 2007).

Advantage/Disadvantages

Advantages

Z-plasty is relatively easy to perform and is a reliable scar revision procedure when the flaps are appropriately designed. It also does not require a significant amount of additional tissue to be excised to perform the procedure, which is particularly helpful in areas with a limited of amount of available adjacent tissue, such as the face.

Disadvantages

To achieve the reorientation and lengthening effects, additional scars are created via the limbs of Z-plasty. The scars become more conspicuous as the length of the limbs increase. Furthermore, on a truly flat surface, transposition of Z-plasty flaps can create visible surrounding soft tissue elevation, known as stereometric gain.

References

Baker SR (2007) Local flaps in facial reconstruction. Mosby Elsevier, Edinburgh

Hove CR, Williams EF 3rd et al (2001) Z-plasty: a concise review. Facial Plast Surg 17(4):289–294

Hudson DA (2000) Some thoughts on choosing a Z-plasty: the Z made simple. Plast Reconstr Surg 106(3):665–671

Papel ID (2009) Facial plastic and reconstructive surgery. Thieme, New York

Rohrich RJ, Zbar RI (1999) A simplified algorithm for the use of Z-plasty. Plast Reconstr Surg 103(5):1513–1517, quiz 1518

Thorne C, Grabb WC et al (2007) Grabb and Smith’s plastic surgery. Wolters Kluwer Health/Lippincott Williams & Wilkins, Philadelphia

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