Split-calvaria osteoplastic rotational flap for anterior fossa floor repair after tumor excision. Technical note.

Abstract

A split-calvaria osteoplastic rotational flap to repair the anterior fossa floor after tumor excision was devised and tested clinically. At surgery, the flap is outlined between the glabella and the vertex. After the pericranium between the glabella and the flap's anterior pole is elevated to form its pedicle, a full-thickness craniotomy is performed to expose the diploic aspect of the bone graft donor site (when the graft is relatively wide, bifrontal craniotomies may be advantageous). The diploic space is split in situ, taking care to protect the pedicle and its attachments to the osseous segment. Linear osteotomies in the outer table are created to mobilize the flap. With the flap rotated frontally, the craniotomy is completed. After tumor extirpation, the margins of the osseous segment of the flap are shaped to conform to the defect of the anterior fossa floor. Transverse osteotomies are performed so that the graft's convex curve conforms to that of the anterior fossa floor. The flap is then rotated into position. Follow-up evaluation in two patients at 22 and 30 months demonstrated bone integrity of the anterior fossa floor with graft preservation. Transient postoperative cerebrospinal fluid (CSF) rhinorrhea, which occurred in Case 1, was avoided in Case 2 by placing the osseous segment of the graft coplanar with the bone floor of the fossa. Neither patient had late meningitis or CSF rhinorrhea. The split-calvaria osteoplastic rotational flap may represent an advance toward the ideal reconstruction of the anterior cranial fossa floor.