Z-plasty

E. J. Mayeaux, Jr, MD, DABFP, FAAFP
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Introduction

Historically, Z-plasty has been a commonly taught and used technique in plastic surgery. It is a type of transposition flap that incorporates principles of both advancement and rotation flaps in its design and execution. Many variations of Z-plasty have been developed, but this chapter focuses on the more common, basic 60-degree Z-plasty technique. The procedure uses the transposition of two triangular flaps to produce a Z-shaped wound. The main indication for performing Z-plasty is to change the direction of a wound so that it aligns more closely with the resting skin tension lines, or so that a scar runs through (instead of across) a joint line. Because the technique increases the length of skin available in a desired direction, Z-plasty also is used to correct contracted scars across flexor creases. The 60-degree Z-plasty lengthens the total scar by 75%. 
The key to a well-designed Z-plasty is symmetry. The length of each lateral limb and the central limb must all be equal. Also the two lateral limb–central limb angles must always be mirror images. This allows the subsequently developed flaps to be easily interchanged. A 60-degree angle between the central limb and the lateral limbs produces the best outcome. This creates two 30–60–90-degree right triangles, which rotates the central line 90 degrees when the flaps are transposed. The two-dimensional geometry dictates that the point-to-point length of the final scar is equal to the square root of three times the length of the original scar or incision. 
When considering the use of a Z-plasty, some physicians theoretically object to the creation of a wound that is three times as long as the original wound in the final maximal length (i.e., the two diagonal arms are as long as the central wound). Although the creation of long wounds is generally discouraged, a well-designed Z-plasty can significantly improve the cosmetic and functional outcome. Z-plasty can be performed on a fresh wound that is counter to the resting skin tension lines, although some experts recommend simple closure of the wound and then Z-plasty at a later date to revise scars that are problematic. Physicians with the opportunity to frequently perform Z-plasty observe generally favorable functional and cosmetic outcomes. 
When performing a Z-plasty, the skin surgeon must practice meticulous attention to technique. When possible, advise the patient to stop taking anticoagulants or aspirin before the surgery. Prophylactic antibiotics may be considered for use in patients with diabetes and in other immunocompromised patients, but data supporting the efficacy of this approach are lacking. The “trapdoor effect,” elevation of central tissue resulting from a downward contraction of a surrounding scar, may be avoided by employing sufficient undermining of tissues surrounding the flap site. Multiple contiguous Z-plasties may be used to break up a long scar line. 

Equipment

  • Surgery tray instruments are listed in Appendix G. Consider adding skin hooks to gently handle the skin flaps. Have at least three fine (mosquito) hemostats to assist with hemostasis while developing large skin flaps.

  • Suggested suture removal times are listed in Appendix J, and a suggested anesthesia tray that can be used for this procedure is listed in Appendix F. All instruments can be ordered through local surgical supply houses.

Indications

  • Revision of contractures or scars that cross flexor creases and result in bowstring-type scars (e.g., vertical scars over the flexor creases of the proximal interphalangeal joints of the hands)

  • Revision of scars that traverse concavities (e.g., across a deep nasolabial fold, a vertical scar that traverses between the lower lip and the chin)

  • Redirection of wounds that are perpendicular to joint lines or the lines of least skin tension (i.e., reorient to a direction that will produce a cosmetically superior result)

  • Creation of wound irregularity (i.e., improved cosmetic results with a line that is broken up or zigzag versus a long, straight line that is less appealing)

  • Repositioning of poorly positioned tissues that produce a trapdoor effect (i.e., rearranging a circular scar that is causing the central tissue to raise upward)

Contraindications

  • Poor skin vascular supply

  • Diseases causing poor vascular supply to the skin (e.g., atherosclerotic heart disease, diabetes, smoking, collagen vascular disease, prior irradiation, severe anemia, anticoagulation)

  • History of poor wound healing, hypertrophic scarring, or keloid formation

  • Uncooperative patient

  • Presence of cellulitis, bacteremia, or active infection

The Procedure

Step 1

The original wound or scar is perpendicular to the line of the nasolabial fold. Contraction of the scar will produce an obvious scar. Prep and drape the area (see Appendix E, Skin Preparation Recommendations). Administer a field block (see Field Block Anesthesia). 

Step 2

The diagonal lines of the Z-plasty are designed to be the same length as the original cut, and they are 60 degrees away from the center line. 
  • PITFALL: Novice providers occasionally make the error of performing their first Z-plasty with the arms on the same side of the central wound. Drawing the proposed Z-plasty helps prevent this problem.

  • PITFALL: Many providers unintentionally incise the diagonal lines at 45-degree angles, rather than 60-degree angles. Flaps in a 45-degree Z-plasty are easier to transpose but only rotate the direction of the original defect by 60 to 70 degrees (rather than 90 degrees with a 60-degree Z-plasty).

Step 3

Incise the diagonal lines, with one arm on each side of the original wound. Undermine the flaps and the surrounding skin in the level of the upper fat (i.e., just below the dermis). Incisions are made vertically through the skin using a no. 15 scalpel blade, or the tissue is dissected using iris scissors. 
  • PITFALL: Failure to undermine extensively makes the transposition very difficult. Liberal undermining is beneficial.

  • PITFALL: Undermine the flaps just below the dermal-fat junction. If too much subcutaneous tissue is attached to the flap, a poorer cosmetic result may result.

Step 4

Transpose the flaps. The upper right flap from above is pulled down and rotated 90-degrees to become the bottom (left-pointing) flap, and the lower left flap from above is pulled up and rotated ninety-degrees to become the upper (right-pointing flap. Note that the ventral line is now in line with the nasolabial fold. 
  • PITFALL: Handle the flaps gently, grasping the skin with skin hooks or Adson forceps without teeth. Many physicians transpose the flaps with toothed forceps, causing tears or damage to the flaps and adding unnecessary scarring.

Step 5

Place corner stitches in the corners of each flap. 
  • Pearl: Consider half-buried, horizontal mattress sutures in place of the simple interrupted sutures (see Corner Suture).

  • PITFALL: Almost all 60-degree Z-plasties performed on human skin result in some pouching upward, or dog-ear formation, at the base of the flap after transposition. They will usually flatten with time, resulting in a good cosmetic outcome.

Step 6

Place simple interrupted sutures to finish closing the suture lines. Keep the stitches on the diagonals to a minimum, and do not place the diagonal stitches near the corners. 

Step 7

A contracted scar commonly results from wounds that traverse the flexor creases on the fingers (bowstring scar). To realign the scar into a more functional alignment, excise the scar, and then draw and excise the lateral arms as described previously. The center of the final wound now runs parallel to the resting skin tension lines. 

Complications

  • Pain, infection, and bleeding

  • Nonunion of skin edges

  • Scar formation

  • Sensory changes, which often subside with time

  • Flap necrosis

  • Hematoma formation

  • Sloughing of the flap caused by high wound tension

  • Trapdoor effect

  • Increased scar length and two additional required incisions

Pediatric Considerations

Generally, pediatric skin has excellent blood flow and heals very well. However, pediatric patients often find it difficult to sit or lie still during lengthy procedures. The patient’s maturity and ability to cooperate should be considered before deciding to attempt any outpatient procedure. 

Postprocedure Instructions

Apply topical antibiotics and a pressure dressing after the procedure. Have the patient keep the bandage on and the wound dry for the first 24 hours. After that, it can be cleaned with hydrogen peroxide or gently washed with soap and water as needed. An antibiotic ointment and bandage should be reapplied until the patient returns or for 2 weeks. Have the patient report signs of infection. Schedule a return appointment for suture removal (see Appendix J, Recommended Suture Removal Times). 

Coding Information

These codes encompass excision or repair, or both, by adjacent transfer or rearrangement, including Z-plasty, W-plasty, V-to-Y-plasty, rotation flaps, advancement flaps, and double-pedicle flaps. When applied to traumatic wounds, the defect must be developed by the surgeon because the closure requires it, and these codes should not be used for direct closure of a defect that incidentally results in the configuration of one of the flaps or plasties. If the configurations result incidentally from the laceration shape, closure should be reported using simple repair codes. 

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