Evaluation with three-dimensional computed tomography after anterior skull base reconstruction using two musculopericranial flaps and a grafted bone.

Postoperative evaluation by three-dimensional (3D) computed tomography (CT) was performed in 15 patients who underwent anterior skull base reconstruction using two musculopericranial flaps and a grafted bone sandwiched between the two flaps. Especially in the case of large bone grafts (4 x 4 cm or more), the graft was positioned with the convex side facing upward into the cranial cavity to avoid creating an intracranial dead space. The extent of the absorption and changes in the contour of the grafted bone were evaluated. Imaging was done at a CT level of 150 using a Proceed 3-D CT scanner (Yokogawa Medical Co., Tokyo, Japan). Donor bone for grafting to the skull base was harvested the cranium in 10 patients and the ilium in 5 others. Patients ranged in age from 7 to 76 years (mean, 47); there were 10 men and 5 women. The grafted bone ranged in size from 1 x 2 cm to 5 x 8 cm (1 x 2 cm to about 4 x 3 cm: 10 patients; 4 x 4 to about 5 x 8 cm: 5 patients).No marked absorption of grafted bone was seen in these 15 patients, and no brain hernia occurred. In patients with large bone grafts (4 x 4 cm to about 5 x 8 cm), a graft that had been positioned with the convex side facing upward into cranial cavity at the time of transplant was subsequently observed to be transformed into a downward convex contour of normal skull base. Fostoperative infection did not occur because of the dead space nor were there any symptom of pressure on the brain because of the upward convexity of the grafted bone.The present reconstructive method is not only a minimum invasive but also a safe and reliable method for anterior skull base surgery.