Results of interspinous segmental instrumentation in the sagittal plane

There is concern that distraction instrumentation with segmental interspinous wiring (ISSI) might flatten the sagittal curves. We studied 110 cases of idiopathic scoliosis treated with ISSI with an average follow-up of > 2 years. The coronal deformity averaged 53 degrees preoperatively with a 58% average correction. For the entire group, the average preoperative thoracic kyphosis was 34 degrees and 32 degrees at follow-up. Children, however, gained an average of 4 degrees of thoracic kyphosis. Children wired to both rods gained 10 degrees in thoracic kyphosis. Preoperative lumbar lordosis was 45 degrees and 42.5 degrees at follow-up. There were five wire breakages in four patients, without loss of correction. There was one deep and one superficial infection and one dysesthesia that resolved. There were no cases of rod failure or pseudarthrosis. ISSI with careful rod contouring can maintain sagittal curves. In children, small improvements in the hypokyphotic spinal deformity can be achieved.