Occipital bone thickness: Implications on occipital-cervical fusion. A cadaveric study

OBJECTIVE: The aim of this study was to create a map of the occipital bone using a cadaveric morphometric analysis. MATERIAL: Twelve heads, from seven male and five female cadavers, were studied. The thickness of the occipital bone was measured with a digital vernier caliper within a coordinate system. RESULTS: The maximum thickness of the occipital bone could be measured at the external occipital protuberance (mean 15.4 mm; range 9-29.3 mm). All male individuals had higher bone thickness around this point. Further lateral a steady decrease of bone thickness could be observed. Same could be observed in craniocaudal direction. However, values above the superior nuchal line were on average thicker than below. CONCLUSION: The measurements demonstrated a great individual variability of bone thickness of the occipital bone. The results emphasize the role of preoperative planning for the feasibility of placement of an occipital screw.