Changes in Volume and Bone Density of Calvarial Grafts After Two Years of Orbital Reconstruction

Abstract

One of the greatest challenges in orbital reconstruction is to obtain adequate orbital volume and globe projection after traumatic injury. Autologous bone graft has been considered the gold standard for orbital floor reconstruction, but the harvesting yields many possible complications, such as donor site morbidity. Bone resorption is a frequent problem that can lead to insufficient volume after graft placement. There is a theoretically lower resorption rate of skull bone grafts, even though the exact amount is not known yet. This study is the first to evaluate bone volume and density changes of calvarial split bone grafts after orbital floor reconstruction with a 2-year follow-up. Bone volume and density of calvarial split grafts were determined using computed tomography scans and the software program RadiAnt Dicom Viewer in a total of 10 patients with orbital floor fracture reconstruction. Computed tomography scans taken immediately after surgery (T0) and after a postoperative period of 2 years (T1) were evaluated. The authors found a mean bone volume reduction of 34.25% after 2 years. Bone density was still high after 2 years (over 850 HU), with a mean reduction of 8%. Based on these findings, calvarial split bone grafts represent the ideal reconstruction material for orbital floor fractures.