Fibrous dysplasia in the spine: prevalence of lesions and association with scoliosis.

BACKGROUND Lesions of fibrous dysplasia involving the spine and scoliosis are thought to be uncommon entities in patients with polyostotic fibrous dysplasia and McCune-Albright syndrome. By examining bone scans of a relatively large cohort of patients with these disorders, we sought to determine the prevalence of spinal involvement and any association with scoliosis. METHODS Sixty-two patients with polyostotic fibrous dysplasia were studied. There were twenty-three male and thirty-nine female patients, and they had a mean age of twenty-five years (range, four to eighty years). Technetium-99m-methylene diphosphonate (MDP) bone scans of the patients were evaluated for evidence of increased uptake in the spine. The presence or absence of scoliosis or a level pelvis and the distribution of other lesions in the skeleton were noted. RESULTS Thirty-nine (63%) of sixty-two patients were found to have seventy-six lesions of fibrous dysplasia in the spine. Fifty-four lesions (71%) demonstrated increased uptake in the posterior aspects of the spine. Most lesions were located in the lumbar spine (thirty-two lesions) and the thoracic spine (twenty-seven), with less frequent involvement in the sacrum (ten) and cervical spine (six). Twenty-five (40%) of the sixty-two patients had scoliosis; seventeen had a thoracolumbar curve; six, a lumbar curve; and two, a thoracic curve. Seven patients had curves that could not be accurately measured by bone scanning and, therefore, could not be classified. Thirty patients (48%) had no evidence of scoliosis. Thus, the prevalence of scoliosis in patients with polyostotic fibrous dysplasia was between 40% and 52%. There was a strong correlation between spinal lesions and scoliosis (p < 0.001) and pelvic asymmetry (p < 0.05). Back pain was an uncommon symptom. Two patients had a neurologic abnormality; neither abnormality was related to the location of the lesions or the curve. CONCLUSIONS Spinal lesions and scoliosis may be more common in patients with polyostotic fibrous dysplasia than has been previously reported. Since there is a strong correlation between a spinal lesion and scoliosis, these patients should be screened clinically for scoliosis. LEVEL OF EVIDENCE Prognostic study, Level II-1 (retrospective study). See Instructions to Authors for a complete description of levels of evidence.