Lumbar spinal changes over 20 years after posterior fusion for idiopathic scoliosis

Lumbar X-ray findings and clinical manifestations were investigated in 10 patients who underwent posterior fusion with or without Harrington instrumentation for idiopathic scoliosis between 1965 and 1975. The subjects were 4 men and 6 women, who ranged from 10 to 17 years of age at the time of surgery (mean, 12 years and 9 months). The postoperative follow-up period ranged from 20 to 30 years (mean, 24 years and 7 months). All patients were followed-up at our institution. Three patients received posterior fusion without instrumentation, and Harrington instrumentation was used in 7 from 1967 onwards. The distal end of the fusion was L2 in 4, L3 in 4, and L4 in 2 patients. Pain, evaluated by Moskowitz's criteria, was stage 1 in 5 and stage II in 5 patients (none of them had stage III or IV). In X-ray evaluation, graded according to Lawrence's classification, grade III changes were noted in 2 patients; one with thoracolumbar fusion with Harrington instrumentation to the L4 vertebra and the other patient was assessed at 30 years post-surgery. According to White-Panjabi's criteria, instability was noted in 1 patient with Harrington fixation including the L4 vertebra. Clinical manifestations and X-ray abnormalities were less severe than anticipated at 20 years plus post-surgery, although a tendency for deterioration was observed in patients with fusion including the L4 or patients followed up for more than 30 years post-surgery.