[The radiotherapy of hyperplastic heterotopic ossification in osteogenesis imperfecta. 2 case reports]

Osteogenesis imperfecta is a rare hereditary disease of connective tissue with a genetic defect in collagen synthesis. In osteogenesis imperfecta hyperplastic heterotopic ossification can be induced by hyperplastic callus formation caused by trauma or operation. Heterotopic ossifications can be found in numerous benign diseases. The successful use of low dose radiotherapy in the treatment of heterotopic ossifications is well-known from the literature.

We treated two children (a 13-year-old girl and a ten-year-old boy) with heterotopic ossifications of the lower extremities in osteogenesis imperfecta type IV (Lobstein) with a low dose irradiation (10 x 1 Gy, respectively 6 x 1 Gy) under megavoltage conditions.

After radiotherapy the children were painfree and the hyperplastic callus was considerably reduced. The previously immobilized patients could partly be mobilized. Thereby it could be contributed to the rehabilitation of the patients. New hyperplastic callus formation was not observed in the irradiated areas so far.

Analogous to the successful radiation of heterotopic ossifications in other benign diseases radiation therapy seems to be a successful treatment of hyperplastic callus formation in osteogenesis imperfecta. Despite the late risks of radiotherapy radiation treatment of benign diseases in children might be indicated.