▸ Trunk. On the anterior trunk, abdominoplasty techniques (with or without tissue expansion) are most effective. "We try to have the challenging part of the reconstruction done while the child is still small and the tissue is more flexible," Dr. Bauer said. But when the nevus encroaches on the breast area, particularly in girls, delay surgery until the breasts have begun to develop in order to avoid an injury to the developing breast bud, he said.
On the posterior trunk, tissue expansion has provided a way to excise many giant nevi with excellent aesthetic and function outcomes, Dr. Bauer said. Transposition flaps from the lower abdomen and the back can be moved longer distances than can the traditional advancement flaps. Flaps can be transposed from the back to the buttocks and reexpanded and brought to the perineal area. And flaps from the lower abdomen can be transposed into the upper-thigh region.
"In some cases, as tissue is moved into the buttock and perineal area, the extra tissue that is gained can be used for genital reconstruction in young girls," Dr. Bauer added. But aside from rare cases, he leaves genital nevi in place in both boys and girls to avoid potential tissue scarring.
Excision of a nevus and coverage of the defect with a split-thickness skin graft are reserved for cases in which there is little, if any, uninvolved tissue available to expand. "The excision is concentrated on the back where the risk of degeneration is thought to be greater and the aesthetic and functional outcome can still be quite acceptable," Dr. Bauer said.
When there is so little uninvolved tissue that there are no acceptable skin graft donor sites, the patient should be followed by a pediatric dermatologist and areas of concern should be selectively biopsied, he said.
In some cases of patients who underwent early excision and skin graft with poor aesthetic outcomes and dense scarring, tissue expansion may be able to provide the normal tissue necessary to excise or revise the scars and provide a more acceptable outcome.
▸ Extremities. The treatment of large and giant nevi on the extremities is especially challenging because the contour from skin grafts is often poor, said Dr. Bauer. Although skin grafts can be used for large nevi on the hands, concerns about mobility and functional problems are significant, he said. "Looking for a better way, we went back to the old plastic surgery techniques and drew from the ideas of pedicle flaps, but we used tissue expansion to advantage," he explained.
For example, tissue expansion from the abdomen and flank can be used to reconstruct large nevi from the wrist to the arm proximal to the elbow. The use of staged, expanded pedicle flaps can yield excellent contour without distortion of the limb. When such flaps are combined with expansion of the scapular region, the extremity can be resurfaced with tissue of similar quality, thickness, and sensibility from the shoulder to the wrist, with the donor scars placed in acceptable positions, noted Dr. Bauer.
Microvascular transfer of expanded skin flapsand some unique application of pedicle-flap principlesmay be used for reconstruction of large and giant nevi of the lower extremity where expansion of that region is less effective. The lower extremity region remains one of the greater challenges in the treatment of large and giant nevi, Dr. Bauer said.
The search for newer approaches, or the application of older techniques in new ways, can lead to improved aesthetic and functional outcomes. But cooperation and understanding from patients and families are the true essentials for successful treatment of large and giant nevi, Dr. Bauer said.
This infant had a circumferential giant nevusfrom above the wrist to the mid upper armthat could have undergone a malignant change.
Skin of the child's abdomen and flank is expanded to create a flap through which the arm will be tunneled after the majority of the nevus is excised.
The baby's arm is shown attached to the created flap. After 3 weeks, the area of attachment can be divided.
The arm after surgery shows excellent contour and color match. Scars are positioned to avoid any late functional disturbance. PHOTOS COURTESY DR. BRUCE BAUER