To analyze surgical outcomes of thoracolumbar and lumbar scoliosis treated with segmental pedicle screw fixation, and to determine the exact distal fusion level.

Seven idiopathic thoracolumbar and lumbar scoliosis patients (6 thoracolumar and 1 lumbar scoliosis, 7 females with mean age of 15.9 years) subjected to segmental pedicle screw fixation with a minimum follow-up of 2 years were retrospectively analyzed for deformity correction, stable vertebra, lower instrumeted vertebral tilt (LIVT) and coronal balance using pre and post-operative standing radiographs. The bending stable vertebra and the rotational correction of L3 were measured in preoperative bending radiographs. The L3 rotation in the bending radiographs was less than Nash-Moe grade II in all patients. The bending stable vertebra was L3 in 4 patients and L4 in 3. An unsatisfactory result was defined as an LIVT of more than 10° or a coronal imbalance of more than 10 mm.

Distal fusion went down to L3 in 6 patients and L4 in one patient whose bending stable vertebra had been L4 preoperatively. The preoperative average major curve of 52° was corrected to 10° (81% correction). The preoperative average thoracic curve of 27° and the average lumbosacral curve of 26° were corrected to 14° and 5°, respectively. Two patients with distal fusion to L3 showed unsatisfactory results; LIVT was more than 10° in both patients and coronal imbalance more than 10 mm in one. Both the patients had bending stable vertebra of L4 preoperatively.

In the correction of thoracolumbar and lumbar scoliosis with segmental pedicle screw fixation, the curve could be fused to L3 when the L3 rotation in the bending radiograph was less than Nash-Moe grade II and the bending stable vertebra was L3.