Natural history of scoliosis in Friedreich's ataxia
Labelle, H.; Tohmé, S.; Duhaime, M.; Allard, P.
Journal of Bone and Joint Surgery. American Volume 68(4): 564-572
1986
ISSN/ISBN: 0021-9355 PMID: 3957980 Document Number: 283144
Does scoliosis associated with Friedreich's ataxia behave like an idiopathic or a typical neuromuscular scoliosis? Should it be treated like an idiopathic or a neuromuscular curve? Since no precise information to answer these questions could be found in the orthopaedic literature, a retrospective study was undertaken of seventy-eight patients with Friedreich's ataxia who had been followed at our neuromuscular clinic. Fifty-six of these patients were found to have typical Friedreich's ataxia in accordance with the criteria of Geoffroy et al., and their cases were retained for analysis. Their mean age was twenty years (range, eight to thirty-three years). The average length of clinical follow-up was nine years and the average duration of radiographic follow-up of the scoliosis was 3.5 years. A scoliosis of more than 10 degrees was found in all patients and was associated with a hyperkyphosis in 66 per cent. Both sexes were equally affected. Fifty-seven per cent of the curves were double thoracic and lumbar; 14 per cent were thoracolumbar; 7 per cent, double thoracic and thoracolumbar; 7 per cent, thoracic; 4 per cent, lumbar; and 11 per cent, multiple small curves. Of the fifty-six patients whose cases were studied, thirty-six had been followed for at least ten years. Among these thirty-six, there were twenty whose curves were more than 60 degrees and progressed (Group I) and sixteen whose curves were 40 degrees of less and did not progress (Group II). Comparison of Groups I and II showed a statistically significant relationship (p < 0.005) between curve progression, young age at onset of the disease, and recognition of the scoliosis before puberty. However, there was no significant correlation between curve progression, degree of muscle weakness, level of ambulatory function, and duration of disease. Although scoliosis in Freidreich's ataxia is classified as neuromuscular, it appears to behave like an idiopathic scoliosis in many respects. The curve patterns are similar, and in both conditions many curves are not progressive, there is no relationship between muscle weakness and the curvature, and onset of the scoliosis before puberty is a major factor in progression. Based on these observations, we recommended the following protocol of treatment: curves of less than 40 degrees should be observed, curves of more than 60 degrees should be treated surgically, and curves between 40 and 60 degrees should be observed or treated surgically, the decision as to treatment being based primarily on the patient's age at onset of the disease, the age when the scoliosis was first recognized, and evidence of progression of the curve.