Hyperrotatory Paradoxic Kyphosis

Abstract

A retrospective radiographic evaluation of 32 patients with hyperrotatory scoliosis accompanied by paradoxic hyperkyphosis, who were treated with posterior multilevel hook instrumentation. To give a three-dimensional analysis of this particular deformity and to evaluate the coronal, sagittal, and horizontal plane corrections in these specific curves. Lordoscoliosis with a severe rotational component produces paradoxic kyphosis in the sagittal plane. A vertebral derotational maneuver is essential to restore the normal sagittal alignment. Thirty-two patients were treated with posterior multilevel hook instrumentation. Nine patients had previously undergone anterior release and fusion. The derotational maneuver could be accomplished in 21 cases. The coronal Cobb angle and the extents of apical vertebral rotation, sagittal hyperkyphosis, upper and lower compensatory lordosis, and sagittal trunk balance were measured after an average follow-up period of 5 years and 9 months. The mean coronal deformity decreased from 89.9 degrees before surgery to 40.7 degrees. The mean preoperative hyperkyphosis was 70.9 degrees in the thoracic spine, 45.9 degrees in the thoracolumbar spine, and 55 degrees in the lumbar region. These values were reduced to 39.7 degrees, 6.8 degrees, and -15 degrees, respectively. The lateral spinal balance changed from -21.3 mm to -8.5 mm. The average rotational correction measured by the method of Jackson was 51% before surgery and 39% after surgery (correction: 23.5%). There was a positive correlation between the preoperative kyphosis angle and the apical rotation (r = 0.58) and between the decrease of kyphosis and the correction of the rotation (r = 0.67) in cases when the derotational maneuver could be accomplished. If the apex of the scoliosis and the kyphosis are on the same level, the vertebral hyperrotation is responsible for the sagittal malalignment. Satisfactory results can be achieved with posterior multilevel hook instrumentation.