Pathomechanics and management of scoliosis in Friedreich ataxia patients: preliminary report.

The preliminary results based on a one year study on the evolution and management of scoliosis are presented. Twenty-one patients were followed in the Neuro-Muscular Disease Clinic at Ste-Justine Hospital where standardized spinal radiographs were taken periodically with the Scoliosis Chariot and the Throne. The short period of observation as well as the relatively small number of Friedreich ataxia patients followed requires that these results and the following remarks be interpreted with caution. Pathomechanics -- Between the age groups I (5 - 10 years) and II (10 - 15 years), a substantial increase in the Cobb values occurs. Associated with it, an increase was observed in the thoracic and thoracolumbar projected surface area indices. The relative rotation between the thoracic and lumbar segments was presumed to be the cause of the sudden increase in the Cobb measurements. For the non-ambulatory patients, a decrease in the lumbar lordosis towards a thoraco-lumbar kyphosis as well as a sudden increase in the sacral angle and a drop in the lumbo-sacral angle were associated with the seated posture assumed by the patient. Management -- Prevention of the progression of established curves was our main objective. Careful examination of the spine, depending on the age of the child, in our preliminary study, stimulated early orthopaedic treatment in any curve of 20 degrees or more. There was always concern for curves of 30 degrees or more. In the growing child, bracing was recommended. In the older child, the curve was usually stable after sixteen years of age. Surgery was usually attempted in curves over 40 degrees in the growing child. The same curve was usually stable after the growth period. For the non-ambulatory patients, the present study suggested the prescription of a molded seat with the following characteristics: i) a posterior lumbar support, ii) low thoracic lateral supports and iii) a slight inclination of the seating system. This was presumed to be beneficial in maintaining stability of the spine. Presently, an evaluation of such a device is under investigation.