SURVIVAL OF SPLIT CALVARIAL BONE-GRAFTS IN A DOG-MODEL

To gain a better understanding of the strength and long term viability of split calvarial bone graft, nine mongrel dogs each received four t rephine craniotomies (1.5 mm diameter). The harvested bone plugs were split through the diploe and a partial-thickness plug was returned to each craniotomy site. The unused partial-thickness plugs underwent str ength testing. After 90-150 days the dogs were sacrificed, bone scans and X-rays of the graft recipient sites performed, and the grafted plu gs harvested for strength testing and histologic examination. Bone sca nning showed increased osteoblastic activity within the grafts, streng th testing showed a progressive loss in strength over the 150 days, an d histologic examination demonstrated a creeping substitution. These r esults imply a similar evolution in strength and remodeling to that se en in long-bone grafts, whose remodeling typically spans 1 year.