External fixation for dynamic correction of severe scoliosis. 
The ideal treatment for scoliosis may be the correction of the factors that cause the disease.  An external fixation device was used in 12 patients to achieve a correction by dynamic distraction, compression and derotation of the curve.  Follow-up was done over a 7-year period.  To describe the treatment of inflexible and severe scoliosis by special correction with external fixation.  This was a prospective, longitudinal and descriptive study, with a follow-up period of 7 years.  Twelve patients (9 female, 3 male) from the National Orthopaedic Institute Spine Service in external consultation.  Radiographic measurements with the scoliosis angulation of Cobb's method were used before surgery, after surgery and in the final follow-up period.  The surgical procedure consisted of two stages, anterior and posterior approach, dissectomies, vertebrectomy at the apex, spinal column shortening and the placement of an external stabilization device.  Progressive correction of the curve was done by a daily increase in distraction (3 mm/day).  When the correction was finished, a different internal fixation device was used to maintain the correction.  The time between initial treatment and final correction was 50 days.  Ten thoracic curves, one thoracolumbar curve and one lumbar curve were treated, with an average of 93 degrees.  All patients had kyphosis with an average of 89 degrees.  Vertebral rotation was not found in two patients.  Average correction of scoliosis was 52.9% and of kyphosis, 29%.  Vertebral rotation in eight cases was corrected.  There were no neurological irreversible lesions in any patient.  There was one infection.  Using an evaluation result scale, there were 2 excellent, 6 good and 4 fair outcomes.  The average loss of correction was 5 degrees.  The results suggest that the use of an external stabilization device with controlled compression on the convexity and distraction on the concavity of the curve can achieve a correction of up to 50% in scoliosis, 30% in kyphosis and 1 degree in the rotation of the spine.