A new design of internal fixation for scoliosis and its preliminary clinical application

A new scoliotone composed of screw, socket, distraction rod, lateral mass and compression rod can produce free movement in three different planes and fix the vertebral column in three-dimensions. The instrument has a strong force of fixation, distraction, compression and anti-rotation and it can be locked in any degree angle. Preliminary clinical application in 10 cases showed that when the spinal curvature (Cobb's angle) was less than 50, the average correction rate of scoliosis was 78.2% and that of the hump was 90%; when Cobb's angle was within 50-100 degrees, the average curve correction was 68.2%, and the hump correction 87.7%; when Cobb's angle was 100 degrees, the average curve correction was 63.3%, and the hump correction 82%. The vertebral column needed no external fixation after the operation. Biomechanical characteristics of the vertebral pedicle, and the technical features are discussed.