Treatment of aneurysmal bone cysts by introduction of demineralized bone and autogenous bone marrow

BACKGROUND: On the assumption that an aneurysmal bone cyst has an intrinsic potential to heal by ossification, a new, minimally invasive protocol was developed. Demineralized bone powder mixed with bone-marrow aspirate was introduced into the cyst to halt the expansion phase and to allow the cyst to ossify. We hypothesized that, in order to induce bone-healing, cells from the cyst are needed to respond to the inductive material but that curettage or extensive surgery is not necessary. The goals of the present study were to assess cyst-healing and to determine the prevalence of recurrence associated with this new procedure. METHODS: Thirteen biopsy-proven primary aneurysmal bone cysts were entered through a small incision, and a paste of demineralized bone and autologous bone marrow was introduced with an applicator. The study group included three male and ten female patients with a mean age of 16.6 years. The cyst was located in a long bone in six patients, the pelvis in five patients, and the scapular glenoid and the calcaneus in one patient each. Five patients had not received treatment previously, whereas one had had a preoperative embolization and seven had recurrent lesions that had been treated previously. RESULTS: After a mean duration of follow-up of 3.9 years, healing was achieved in eleven patients. CONCLUSIONS: This minimally invasive method is able to promote the self-healing of a primary aneurysmal bone cyst. As no curettage is required, the proposed treatment avoids extensive surgery and blood loss and is convenient for the treatment of poorly accessible lesions such as those occurring in the pelvis. LEVEL OF EVIDENCE: Therapeutic Level IV.