Cranioplasty (Autogenous, Cadaveric, and Alloplastic)

Indications

• In general, we prefer to use autologous calvarial bone grafts as the primary material for cranioplasty and skull reconstruction. Autogenous graft material typically has a low incidence of infection, grows with a child, and has highest rate of functional integration. It is usually obtainable in proximity to the defect site, and resorption tends to be minimal. However, the defect size cannot be larger than the amount of remaining diploic bone available for harvest.

• We tend to use split rib or iliac crest grafts in patients with large defects who are opposed to alloplastic reconstruction or in whom a prior infection has occurred. Autogenous bone is our first choice in patients with a history of scalp irradiation, provided that the scalp blood supply is intact. In patients with compromised soft tissue coverage, free tissue transfer may be necessary for coverage of autogenous or alloplastic calvarial reconstruction.

• When the defect is larger than the amount of remaining diploic bone available for harvest, we typically utilize prefabricated implants made of various synthetic materials, such as methyl methacrylate and porous, linear, high-density polyethylene (MEDPOR, Porex Surgical, Inc., Newnan, GA). These implants are constructed using three-dimensional reconstructed images derived from “fine-cut” computed tomography (CT) scans.

• Calcium phosphate bone void filler is an option when smaller gaps in bone are present (< 2 to 3 cm) or when contour irregularities require augmentation. Cadaveric bone and demineralized bone paste are viable options for filling in small bony gaps. In children younger than 5 years old, in whom the diploic space is not fully formed, demineralized bone grafts are also useful to fill moderately large defects. In using calcium phosphate bone cements or similar products, dural pulsations may be disruptive to the material before it hardens. In this instance, either resorbable or titanium mesh may be used to cover the dura prior to bone cement being overlaid on the mesh to fill the defect.