Experimental heterotopic bone transplant.

We studied the reaction in rats to implants of heterotopic bone in the paravertebral region, using three types of material: bone preserved in alcohol, homologous bone preserved in alcohol associated with autogenous cancellous bone obtained from the iliac crest of the same animal, and isolated autogenous cancellous bone. Thirty rats were operated on, ten in each group. Some were sacrificed after 6, 14 and 21 days. The excised grafts were histologically studied. Animals in the third group showed new bone formation even in the first days, those in the second group presented less intense bone formation and those in the first group showed only traces of new bone tissue in the third week.