[Aneurysmal bone cyst of the spine in children: a 9-year follow-up of 7 cases and review of the literature].

PURPOSE OF THE STUDY: Aneurysmal cyst is an uncommon benign primitive bone tumor generally observed in young subjects, in a spinal localization in 10% of the cases. We report the clinical, radiological, and therapeutic aspects of seven cases of aneurysmal cyst of the spine.

MATERIAL AND METHODS: This series included seven children, mean age 11.7 years (range 8-14) who were followed for 9 years on the average (range 2-24 years). Findings were compared with reports in the literature.

RESULTS: Four cysts were located in the cervical spine (C1, C3, C4, C7), two in the thoracic spine (T4, T7) and one in the sacrum. Biopsy-resection was performed in six patients. The sacral cyst was treated by selective arterial embolization. Two complications were observed after surgical treatment. Bony filling of the lesion, evaluated by CT scan six months after surgery, was achieved in five cases, incomplete in two without recurrence of cystic cavities.

DISCUSSION AND CONCLUSION: Aneurysmal bone cysts account for 15% of all primitive tumors of the spine. They are more frequent in the cervical and thoracic spine than in a lumbar or sacral localization. One vertebra is involved in most cases, generally the vertebral body and the posterior arch with an asymmetrical extension to one pedicle in some cases. Neurological complications of variable severity are frequent and can be improved by surgical removal of the tumor. CT scan and MRI are the best exams to analyze the spinal cyst, to show bony walls and liquid-liquid levels suggestive of aneurysmal bone cyst, to evaluate the tumor extension and to search for cord compression. When the CT scan and MRI show characteristic signs of aneurysmal bone cyst of the spine, we do not perform a biopsy systematically if complete removal of the tumor appears possible. Surgical removal with biopsy is the treatment of choice. Reconstruction and stabilization of the spine must be complete using bone graft with or without instrumentation. In case of medullary involvement, decompression must be performed rapidly with the most complete tumor removal as possible. Selective arterial embolization can be used in some localizations or as preparation to surgery. Radiotherapy is contraindicated in children because of the risk of radio-induced tumors.