A new instrumentation for posterior spinal surgery consists of metallic rods carved with diamond-shaped asperities on which vertebral hooks or screws can be screwed in any position, level, or degree of rotation. The rods are interlocked by means of devices for transverse traction (DTTs), rectangular constructs with multiple vertebral grips, the stability of which allows suppression of any postoperative external support. Initially designed to treat scoliosis, this instrumentation design allows mobilization of the vertebrae located at the apex of the curve and obtains a three-dimensional correction. Correction of the areas of the most important structural deformation can also be obtained at the level of the end vertebrae, without any need to resort to an important distraction force. The technique varies according to the various types of curvatures. Approximately 250 patients were operated upon from 1983 to 1985. In idiopathic scoliotic curvatures, the mean percentage of correction was 66%. An important improvement of the associated sagittal deformations and of the apical derotation was observed in flexible curves. In paralytic curves, particularly with a pelvic obliquity, the percentage of correction of the frontal deformation is 77%. All of the spine patients were ambulatory in the first postoperative week, without any external support, and returned to their school or family activities. In 43 patients with follow-up periods longer than two years, there were no technical errors in 38. The final angular loss of correction was less than 2[degrees] in the error-free group.
(C) Lippincott-Raven Publishers.