Scalp Tissue Expansion Above a Custom-Made Hydroxyapatite Cranial Implant to Correct Sequelar Alopecia on a Transposition Flap

International audienceBackground:Resection of cranial tumors involving both bone and scalp tissue may require the recruitment of soft tissue using a flap above the bone reconstruction. When a transposition flap has been chosen, the alopecia zone on the donor site may be difficult to treat afterward. Scalp expansion is the gold standard in these situations, but this has never been described above cranial implants. We report the first case of a patient who underwent a scalp tissue expansion above a custom-made hydroxyapatite cranial implant to correct sequelar alopecia.Case Description: A 30-year-old man presented with a dermatofibrosarcoma of the scalp with bone invasion. A cranioplasty with a custom-made hydroxyapatite implant and a transposition flap were performed. Although healing was achieved, the donor site of the transposition flap left a 9 × 13 cm sequelar alopecia area on the vertex. To correct it, a rectangular 340-cm3 expander was partially placed above the cranial implant and under the transposition flap. A second 120-cm3 expander was put on the contralateral temporal region. The expansion was successful. No expander infection, cranial implant displacement, or fracture on imaging performed during the follow-up period was detected. The alopecia zone was entirely excised. The patient was very satisfied with the cosmetic result.Conclusions: Tissue expansion above hydroxyapatite implants may be of concern to the physician because of the risk of infection and rupture of the cranial implant. With this clinical case, we emphasize some precautions to prevent these issues