Abstract: Reconstruction of cutaneous scalp defects from tumor ablation are currently managed with a wide array of coverage options. These include split- or full-thickness skin grafting, local or regional flaps, tissue expansion, and free tissue transfer with variations and combinations thereof. Many of these options require multiple procedures, significant donor site morbidity, complex surgical techniques, attendant blood loss, and other associated surgical risks. The use of a dermal regeneration template (DRT) (Integra®, Integra Life Sciences, Plainsboro, New Jersey) obviates many of these disadvantages and can safely be performed under local anesthesia or as an outpatient procedure. The following case report describes the successful use of Drt with an ultra-thin split-thickness skin graft to reconstruct an 11cm x 11cm scalp defect after margin free excision of a malignant fibrous histiocytoma.

Introduction

Malignant fibrous histiocytoma (MFH) is the most common soft tissue sarcoma of adults. It is an aggressive soft tissue malignancy that is most commonly found in skeletal muscles or retroperitoneum. Cutaneous cases of MFH have been reported and commonly originate in the dermis and invade surrounding tissues.[1] The principle treatment modality for MFH is surgical excision with wide tumor-free margins. Reconstruction of partial- or full-thickness scalp defects encompasses many different techniques including the use of split-thickness skin grafts (STSG), full-thickness skin grafts (FTSG), local or regional flaps, tissue expansion, and free tissue transfer.

Integra® dermal regeneration template (DRT) (Integra Life Sciences, Plainsboro, New Jersey) was initially approved for use in acute life-threatening burns.[2] It is a bilayered construct consisting of a dermal replacement layer comprised of a porous matrix of fibers derived from bovine tendon collagen and shark glycosaminoglycans covered by a substitute epidermal layer made of synthetic polysiloxane polymer.[3,4] As the dermal replacement layer transforms into neodermis, the silicone layer is removed and an ultra-thin split-thickness skin graft (ut-STSG) is applied onto the neodermis. With its successful adjunctive use in burn reconstruction, the use of Drt is evolving into other areas of reconstructive surgery.

The following case report describes the successful use of Drt to cover a large defect created by excision of a cutaneous scalp MFH in an 87-year-old man. Immediate wound coverage was performed with the DRT pending final pathology results. Ultra-thin split-thickness skin grafting (0.007 of an inch) was then performed at a second-stage procedure three weeks after surgical excision and after confirmation of tumor-free margins. Both the initial excision and application of DrT followed by grafting were performed under local anesthesia and mild sedation due to the patient’s advanced age and medical condition on an outpatient basis without complication or morbidity. This relatively simple reconstruction method has provided a stable, durable, and aesthetically acceptable result throughout the follow-up period.

Case Report

An 87-year-old Caucasian man with a past medical history significant for hypertension, coronary artery disease, myocardial infarction, congestive heart failure, chronic lymphocytic leukemia, and melanoma of the scalp (treated with excision and skin grafting) presented with an indurated lesion over the left temporoparietal scalp (Figure 1). An incisional biopsy of the mass definitively identified it as a MFH.

Figure 1

Scalp lesion diagnosed to be MFH. Two centimeter margins are outlines with the solid blue line. The dotted line marks the tumor. Note the healed STSG on the site of previous resection of melanoma medially.

Due to the patient’s advanced age and medical condition, he was taken to the outpatient procedure room for resection of the lesion under monitored anesthesia. The lesion was excised with 2cm margins peripherally and deep margins down to and including the periosteum. The outer table of the exposed skull was burred down until punctuate bleeding was obtained. Because of the poor cosmetic result from the patient’s previous STSG for melanoma and the uncertainty of margins, the decision was made to use Drt for coverage. After achieving hemostasis, a large sheet of DRT was tailored to fit the defect and stapled into place (Figure 2). The length of the procedure was one and a half hours. A bolster followed by a compression head dressing was placed followed by discharge home the same day after a four-hour recovery period.

Figure 2

This photo shows the dermal regeneration template in place after resection of tumor.

Permanent pathology report was received 10 days thereafter revealing pleomorphic spindle cells with hyperchromatic nuclei, irregular nuclear outline, and multinucleated giant cells. There were 16 mitoses per 10 HPF, and the tumor cells were noted to be infiltrating into the subcutaneous tissues. Immunocytochemical stains were positive for Vimentin and CD68, confirmatory for MFH. All margins of tissue were free of tumor cells.

Three weeks after the initial excision and DRT application a pale whitish-yellow hue was appreciated beneath the superficial silicone layer of the DRT indicative of adequate neodermis generation. The patient was taken back to the operating room where the silicone layer of the DRT was removed followed by the harvest of a left lateral thigh ut-STSG (0.007") meshed 1.5:1. The graft was applied to the scalp defect and stabilized with staples, semi-occlusive, antibiotic-impregnated dressing, and a compression head wrap. The patient was discharged from the hospital without complication and was followed on an outpatient basis.

A focal region of poor graft take was noted at the periphery of the wound (Figure 3), which went on to heal with an aesthetically acceptable result with local wound care. The left, lateral, thigh donor site wound was completely healed at the one-week clinic visit. The patient was followed for five months without further wound breakdown or tumor recurrence. He was pleased with the esthetic outcome of the reconstruction. Unfortunately, the patient succumbed to his lymphoma.

Figure 3.

Ten weeks postoperative view of healed wound after application of 0.007-inch thick STSG. Note the small region of breakdown superiorly.

Discussion

First described by O’Brien and Stout5 in 1964, MFH is an aggressive soft tissue tumor that commonly occurs in the skeletal muscles and retroperitoneum of adults 50 to 70 years of age. Controversy exists regarding the histologic origin of these tumors. It is possible that the origin is of a more primitive mesenchymal cell with potential to differentiate into both fibroblasts and histiocytes. The classic description of MFH is spindled (resembling fibroblasts) and rounded (resembling histiocyte) cells arranged in a storiform pattern. These are accompanied by pleomorphic giant cells and inflammatory cells.

Surgical resection is the principle method of treating MFH. Five factors have been shown to correlate poorly with recurrence after resection of the lesions from patients diagnosed with MFH including advanced age, deeply seated lesions, surgical grade, large size, and inadequate surgery.7 Because inadequate surgical resection has been linked to poor prognosis, it is essential to take a circumferential margin of approximately 2cm around the tumor.[1,8,9] Curative resection with free margins results in local recurrence rates of five percent.10 The deep margin usually is excised down to the periosteum. However, if there is involvement of periosteum and the outer table of the calvarium, some have advocated partial removal of the outer table.[11] MFH that originates in the subcutaneous tissue has a tendency to be infiltrative.[1] Therefore, it is important to ensure tumor-free margins. The resultant surgical defect often times does not allow for primary closure, necessitating some form of reconstructive procedure.

Many algorithms for scalp reconstruction have been described. The authors are adding another option to the armamentarium available to the reconstructive surgeon, namely the use of DRT. DRT consists of two layers. The main construct is an amalgamation of cross-linked bovine collagen and shark glycosaminoglycan (chondroitin-6-sulfate). This layer serves as a matrix for the migration of fibroblasts and other cells that are involved in the healing process. It is covered by a silicone pseudo-epidermal layer. This layer provides immediate closure of the wound, forms a barrier to the external environment, and prevents the loss of metabolites and cells from the wound bed.[3,4]

Histologic studies have shown that DRT placed on a wound site undergoes many changes in the process of forming the neodermis. Initially, there is adherence of the matrix to the wound followed by matrix edema over the ensuing week. Fibroblasts start to migrate into the matrix and are present by the first week post application when collagen production commences. Finally, neovascularization occurs during the second to fourth week, which leads to the replacement of the dermal construct with a neodermis to accept ultra-thin skin graft coverage.[12]

The use of DRT provides numerous advantages to the patient. The dermal template of DRT helps to minimize contracture and scarring.[13] The resulting healed wound is uniform in color and texture and not adherent to deeper structures. The second stage of the procedure replaces the silicone layer with an ultra-thin skin graft (as thin as 0.006 of an inch).[14] The thinness of the graft allows for rapid donor site healing and minimal accompanying discomfort.
Regular-thickness skin grafts, either split or full thickness, can result in excessive pain, infection, prolonged periods of healing, delayed mobility, hypertrophic scarring, undesirable pigmentation changes, fluid loss, and thin skin poorly resistant to everyday trauma.[15] These problems are particularly debilitating for elderly patients with other more pressing medical conditions. Local, regional, or distant flaps provide ideal tissue reconstruction for scalp defects but normally require a general anesthetic for transfer. The procedure can be quite complex and physiologically demanding. Furthermore, flap elevation and transfer is associated with multiple surgical risks, including blood loss, infection, flap necrosis, and donor site morbidity.[16] In healthy patients, the morbidity associated with flap reconstruction or tissue expansion may not be considerable. For many elderly patients with pre-existing, potentially life-threatening medical conditions, simpler alternatives that can be performed with minimal physiological stress and morbidity are favored. Microsurgical flaps involve a long operation and hospitalization and can be quite difficult to perform in the elderly and individuals with multiple medical problems. Quality-of-life issues are affected as well. Tissue expansion is time consuming and, in a cancer operation, not very conducive to the mode of therapy not to mention the multiple operations and office visits required and the great cost.

The use of DRT is not free of complications. Sheering, graft loss, hematoma formation, infection, silicone layer detachment, and incomplete take of epidermal graft have been reported.[17] Most of these are issues that can be avoided and minimized with meticulous wound care and good operative techniques.[18] The cost of DRT is also another factor that one must consider in its use. A 4x10-inch sheet of Integra costs approximately $1,000. This cost, however, is offset by the shorter operating room time and hospital stay.

In a cancer operation where tissue pathology is important, another advantage of the use of DRT is demonstrated. It provides a biological dressing and gives time for the definitive tissue diagnosis of the specimen sent to pathology. In addition, the margins of resection will be processed to ensure no tumor involvement. This is very important since inadequate resection has been shown to correlate with higher rates of local recurrence. If the initial resection is not adequate, one can take the patient for further resection, since no definitive procedure has been performed. It gives the surgeon and the pathologist the opportunity to ensure complete resection of the tumor.

In addition, people who have multiple medical problems get the benefit of a short procedure that may not even require general anesthesia. In this patient, the procedure was performed under sedation and local analgesia, avoiding the complications associated with general anesthesia. These complications include myocardial ischemia, ventricular tachyarrhythmia and other cardiac complications, pulmonary complications, hypothermia, and drug interactions, which might lead to significant morbidity and mortality.[19] The elderly population with multiple medical problems and use of multiple medications are more likely to suffer the adverse effects of general anesthesia.

Finally, a potential advantage of scalp reconstruction with DRT is that it is amenable to hair transplantation. In cases where the patient may desire to have hair in the area of reconstruction, one is able to transplant hair onto the fully healed skin on the scalp. The authors have performed a successful hair transplant in a patient after post-traumatic reconstruction of a scalp defect with DRT and ut-STSG.[20]

Conclusion

The use of DRT has now been expanded into reconstructive surgery. This product can be used in defects from wounds created by extensive resections. It is also ideal for use in older patients and in patients with poor healing capabilities secondary to multiple medical problems. These patients might further benefit from the use of DRT since its application does not involve long surgeries and hospitalization as do other methods of repair. The wound healed with the use of DRT in this case report was stable and acceptable cosmetically.