A New Modification of Z-Plasty

Abstract

Sir: It is well known that a scar perpendicular to the relaxed skin tension line tends to become hypertrophic. Z-plasty is an effective technique to prevent this hypertrophic change. By performing Z-plasty, a scar perpendicular to the relaxed skin tension line is realigned parallel to it, becoming less likely to develop hypertrophic change. However, the whole part of the scar produced by the Z-plasty is not parallel to the relaxed skin tension line. The lateral limb remains, forming a steep angle against the line even after Z-plasty is performed. For example, in the most conventional Z-plasty, where a pair of equilateral triangular flaps is used, lateral limbs form a 60-degree angle against the relaxed skin tension line at the completion of the procedure. Since 60 degrees is a steep angle, although not as steep as the right angle, the lateral limbs tend to become hypertrophic postoperatively (Fig. 1, above).Fig. 1.: (Above) Conventional Z-plasty and postoperative change of the scar (above, left and center). In conventional Z-plasty, a scar perpendicular to the relaxed skin tension line (thin parallel lines) is realigned parallel to the line. (Above, right) Thus, we can expect the central limb to become inconspicuous. However, since the lateral limbs form a steep angle against the relaxed skin tension line, they tend to become hypertrophic over time. (Below) In our technique, each limb of the flap forms a lazy S shape, so the lateral limbs are less likely to become hypertrophic postoperatively.To prevent this unfavorable outcome, we developed a new technique by modifying conventional Z-plasty. We design each limb of the Z-flap as a curved line (lazy S) instead of the straight line used in conventional Z-plasty. The shape of the each lazy S curve must be identical for all the limbs produced in one Z-plasty. We adjust the degree of the curvature of the lazy S on a case-by-case basis. After the design is completed, two flaps are raised, rotated, and recombined. The lateral limbs, as well as the central limb, form a lazy S shape. Since a curved scar tends to become less hypertrophic than a straight scar if they form the same inclination against the relaxed skin tension line, we can expect the lateral limbs produced with our new technique to become less hypertrophic than those produced with conventional Z-plasty. Thus, we can prevent the above-mentioned problem of the lateral limbs’ hypertrophy. Figure 2 demonstrates a case of scar revision where we used our modified Z-plasty for a forehead scar on a 15-year-old boy. The lateral limbs are inconspicuous at 1 year after the operation, proving the effectiveness of our technique.Fig. 2.: (Left) Our modified technique was applied to the scar on the forehead of a 15-year-old boy. (Right) At 1 year after the operation, the lateral limbs, as well as the central limb, have become inconspicuous.Generally speaking, straight scars are not favored by plastic surgeons. Few plastic surgeons adopt straight scar incisions for rhytidectomy, cranioplasty, removal of tumors–-almost all operations in the field of plastic surgery–-because it is commonsense for plastic surgeons that straight scars tend to become conspicuous compared with curved scars. However, strangely enough, little attention has been paid to the straight line in the conventional Z-plasty, though various modifications of it have been reported in the literature.1–5 At the recognition of this paradox, we modified the conventional Z-plasty. Lateral limbs, after being transformed from a straight line to a curved line with our technique, are expected to become inconspicuous postoperatively. Although our technique requires some effort to perform because of its elaborate design and flap-trimming processes, it contributes to patients’ satisfaction. We recommend our technique as a useful option for scar revision operations. Tomohisa Nagasao, M.D., Ph.D. Junpei Miyamoto, M.D. Kaichiro Yoshikawa, M.D. Tatsuo Nakajima, M.D., Ph.D. Department of Plastic and Reconstructive Surgery Keio University Hospital Tokyo, Japan Maki Nagasao, M.D. Department of Otonasolaryngology Itabashi Ear, Nose, and Throat Hospital Tokyo, Japan