[Long-term follow-up after posterior corrective operation for degenerative scoliosis]

To evaluate the clinical outcome of posterior corrective operation for degenerative scoliosis and analyze the possible reasons for its late complications and their proper management.

Thirty-five patients with degenerative scoliosis, who were treated by posterior pedicle screw fixation and interbody fusion with cage implantation from September 1997 to September 2002, were reviewed. Their clinical outcomes were determined according to Oswestry Disability Index (ODI). The fusion area and its adjacent segments were evaluated through radiographic measurements of coronal Cobb angle, lumbar lordosis and coronal balance of the spine. The association of late complications, spinal alignment, and range of fusion was analyzed.

At final follow-up, ODI was 17.8 - 62.2 (average 34.7). Late complications occurred in 13 patients, accounting for 37.1%. Among the 13 cases, 10 were symptomatic and 6 received revision surgery. The late complications were proximal junctional scoliosis in 4 patients, proximal junctional kyphosis in 4 patients, proximal compressed vertebral fracture in 1 patient, pseudarthrosis in 1 patient, pedicle screw loosening in 1 patient, and distal segment degeneration in 1 patient. Junctional kyphosis had no obvious relationship with abnormality of spinal alignment. Adjacent segment degeneration occurred more commonly in the cases with the proximal ultimate vertebra below L1 (9/ 18) than above T12 (4/17).

The rate of late complications is relatively high after posterior corrective operation for degenerative scoliosis. Spinal alignment should be evaluated carefully in preoperative planning. The proximal ultimate vertebra should be extended to the level above T12 to avoid late complications.