Induced healing of aneurysmal bone cysts by demineralized bone particles. A report of two cases.

Two cases of induced healing of aneurysmal bone cyst (ABC) following intralesional implantation of a bone paste made of autogeneic bone marrow and allogeneic bone powder are reported. The calcaneum in one case and the superior pubic ramus in the other were blown out by an ABC and would have required extensive surgery. Via a minimal exposure, the cyst was partially evacuated and filled with an admixture of a partially demineralized bone particles with bone marrow. Ossification of the peripheral shell was the first sign of healing and was observed within the first 3 postoperative months. Successful healing was observed in both cases. The rationale underlying this intralesional treatment was that the bone grafting material might reverse ABC expansion by promoting ossification through a bone induction mechanism. The concept of this treatment was to retain the ABC tissue, using its own intrinsic osteogenic potential to promote healing. By triggering intralesional new bone formation, the bone paste represented an effective means to reverse the expanding phase of ABC. The particulated bone allograft was easy to handle and to introduced in an irregular cavity. Moreover, as a complete cyst evacuation was not required, a minimal surgical approach could be used so that the risks and morbidity associated with an extensive approach were reduced. Its use is of particular interest in poorly accessible areas like the pelvis and spine.