Early surgical consultation is imperative for pigmented lesions that cannot be closed in a primary fashion. In ideal circumstances, the family is educated about the surgical risks, potential benefits, and the available procedures for their child soon after birth. The complexity of the surgical options, potential morbidity, and possible need for multiple procedures can make these discussions difficult for the family, and their expectations whenever they opt for an intervention must be managed appropriately.
As previously stated, early consultation and operative intervention is ideal when managing larger lesions for several reasons. First, the risk of malignant transformation to melanoma for giant CMN is greatest during the first decade of life with over 50% occurring before 3 years of age. Secondly, the elasticity of the skin in younger children, especially infants can allow for fewer procedures and more aggressive single-stage excisions (Fig. 96-5). Finally, the psychological benefits of operating prior to entering school, coupled with the ability to tolerate multiple operations or tissue expansion, further strengthen the argument for early intervention. The current armamentarium in the treatment of large pigmented lesions includes serial excisions, skin grafting, and tissue expansion. Autologous free tissue transfer and other flap reconstruction techniques are also available in select cases yet their description is outside the scope of this chapter.
A. Large congenital melanocytic nevus involving the dorsal thorax in a 6-week-old infant. B. Postoperative view after a single stage excision in an outpatient setting.
Serial excision is a relatively straightforward, reliable technique that is best reserved for lesions that can be addressed 2 stages or less. The recommended interval between stages is generally between 3 and 12 months to allow for adequate healing and relaxation of the adjacent tissues to permit another operation. The simplicity of this technique is its primary advantage and it is particularly useful for patients and families who cannot tolerate the psychosocial stress of undergoing tissue expansion. The potential for scar spread and hypertrophy is certainly a risk given that incisions are closed under some tension; however, it does obviate the need for multiple visits and the potential complications associated with tissue expansion.
The utilization of skin grafts is another reliable technique for reconstructing the deficit left after the excision of large lesions. The primary advantage of skin grafting is the ability to resurface large areas in a single stage. The aesthetic results are further enhanced with the use of nonmeshed split-thickness grafts and full-thickness grafts taken from strategic donor sites to obtain an acceptable color match. Unfortunately, the morbidity associated with skin graft based reconstructions limits its utility. With the exception of full thickness grafts, the donor site can be extensive, leaving another wound not exempt from potential healing and scarring problems. In addition, skin grafts applied to fascial excisions are significantly disfiguring unless the lesion is merely resurfaced. As previously mentioned, resurfacing techniques leave behind residual nevus cells with the potential for malignant degeneration. For these reasons and the availability of other techniques, the widespread use of skin grafts is limited.
Tissue expansion provides versatility that techniques based upon serial excision or skin grafting fail to offer. Its application should be advocated if 3 or more stages are anticipated to complete a reconstruction. The primary advantage of this technique is its ability to increase the availability of soft tissue with properties that are identical to the normal adjacent tissue. Thus, the skin color, texture, and in the scalp, hair can be incorporated into the reconstruction. For these reasons, tissue expansion is an ideal technique for large pigmented lesions in the scalp (Fig. 96-6) and trunk (Fig. 96-4). For particularly large lesions, multiple expansions can be performed including the previously expanded flap. In most circumstances, the expansion process is undertaken in an outpatient setting over the course of 3 months with weekly office visits. It is our practice to overinflate the expander beyond the manufacturer's guidelines and to proceed with expansion until the time of removal. Despite these advantages, tissue expansion is not without its drawbacks and potential complications. The complication rates reported in the literature range from 13% to 20% that include reports of pain with expansion, seroma formation, hematoma, infection, and flap loss.
A. Initial result after a planned staged excision of a moderately sized congenital melanocytic nevus. B. Postoperative view after placement and subsequent expansion of a scalp expander. C. Following removal of scalp expander, excision of nevus and flap advancement.
The most critical practical consideration is the ability of the family and the patient to cooperate throughout the expansion process. This includes multiple office visits and the psychosocial stress for the patient and the family associated with having an implanted expander. Additionally, tissue expansion has not been universally successful in all anatomic locations. Corcoran, Kryger, and Bauer have reported the successful use of tissue expansion of the extremities in association with transposition flaps, free flaps and full thickness skin grafts. It has been our experience that the use of tissue expanders in the extremities is limited. The ability to recruit adjacent tissue, the potential for compartment syndrome and high complication rates has changed our approach in the extremity to subcutaneous excision and skin grafting (Fig. 96-4B,C).
The scalp is another anatomic site that warrants special consideration before undergoing expansion. Approximately 50% of the scalp can be reconstructed with tissue expansion without significantly thinning the hair. This technique should be used with caution; however, in younger children given the thinning of the calvarium that can occur with expansion. In a clinical series by Bauer, and in our experience, there has been no evidence of permanent calvarial deformity, nor any detrimental effects to open cranial sutures after expansion. Remodeling of thinned calvarium and areas of deformation at the site of the inflated expander generally occurs within 3 to 4 months.