SPINAL DEFORMITY IN PATIENTS WHO HAVE FIBRODYSPLASIA OSSIFICANS PROGRESSIVA

We reviewed roentgenograms and clinical records in order to characteri ze the spinal deformity in forty patients who had an established diagn osis of fibrodysplasia ossificans progressiva. Twenty-six (65 per cent ) of the patients had scoliosis, which, according to the clinical reco rds and the recollection of the patients, had been present during chil dhood. Twenty-three (88 per cent) of the twenty-six curves were unbala nced c-shaped curves, while the remaining three (12 per cent) were bal anced s-shaped curves. Twenty-one (91 per cent) of the twenty-three c- shaped curves involved the thoracolumbar or lumbar spine. The c-shaped curves ranged in magnitude from 15 to more than 80 degrees. Curves be came rigid by early adulthood and many resulted in severe pelvic obliq uity with impaired sitting or standing balance. An osseous bridge deve loped between the posterolateral aspect of the iliac crest and the pos terolateral aspect of the rib cage in twenty-two (55 per cent) of the forty patients. Nineteen (86 per cent) of these twenty-two patients ha d scoliosis; there was a significant association between the developme nt of scoliosis and the presence of the osseous bridge (p < 0.005). Os sification of the paravertebral muscles and fascia during the first de cade of life limited the development of a normal thoracic kyphosis in ten (42 per cent) of twenty-four patients for whom lateral roentgenogr ams of the spine were available. A spinal orthosis was used to treat t he scoliosis in two patients, but this method resulted in breakdown of the skin and failed to halt progression of the curve. Five patients h ad operative procedures to correct the scoliosis, in the hope of obtai ning a balanced fusion of the spine. Five of the procedures either fai led to halt progression of the curve or were associated with exacerbat ion of heterotopic ossification at sites remote from the operative fie ld. While our series is small, and while we cannot completely dismiss the option of operative treatment of scoliosis in patients who have fi brodysplasia ossificans progressiva, we believe that operative interve ntion is rarely indicated because of the numerous and severe complicat ions: most notably the exacerbation of heterotopic ossification at sit es remote from the operative field.