The dangers of intraosseous fibrosing agent injection in the treatment of bone cysts. The origin of major complications shown in a rabbit model.

Direct intraosseous injection of fibrosing agent is widely used in the treatment of aneurysmal bone cysts. The purpose of this study was to evaluate the consequences of fibrosing agent penetrating the medulla of bones. This may be the case when, by mistake, the fibrosing agent is administered into the medulla or when the wall of the cyst ruptures and fibrosing agent is able to drift into the medulla. Twelve rabbits were injected transcutaneously with a fibrosing agent directly into the proximal metaphysis of the tibia. Prior to injection 0.5 ml of liquid-like, bloody, intraosseal tissue was aspirated, then 0.5 ml of fibrosing agent was administered. Fibrosing agent was introduced slowly (20 s) to avoid overpressure. Nine rabbits (75%) died within minutes after the introduction of fibrosing agent. A full body roentgenogram was taken of each rabbit and the animals that died underwent autopsy to find the exact cause of death. Roentgenograms of the chest showed massive multiple pulmonary emboli confirmed in all lethal cases by the autopsy. This animal model was created to draw attention to the dangers of any leakage of the fibrosing agent into the medulla of bones.