Purpose: To review early radiographs of patients with de novo degenerative lumbar scoliosis to determine factors predicting early scoliosis progression.
Methods: Standing anteroposterior and lateral radiographs of 7 men and 20 women aged 48 to 83 (mean, 63) years with Cobb angles between >5º and <20º were reviewed. They were followed up for a mean of 12 (range, 10-18) years. Radiographic variables measured included (1) the Cobb angle, (2) the grade of rotation of the apical lumbar vertebra, (3) the presence of a lateral vertebral translation of ≥3 mm, (4) the degree of osteoporosis, and (5) the Harrington factor (the degree of scoliosis divided by the number of vertebrae involved).
Results: During the follow-up period, the mean Cobb angle increased 5.3º from 10.1º to 15.4º, representing an increase of 0.4º per year. In initial radiographs, the apical vertebral rotation was rated as grade 0 in 3 patients, grade 1 in 19, grade 2 in 4, and grade 3 in one. A lateral vertebral translation of ≥3 mm was noted in 9 patients. The degree of osteoporosis was rated as grade 0 in 9 patients, grade 1 in 11, grade 2 in 5, and grade 3 in 2. The mean Harrington factor was 2.4. In the multiple regression analysis, only the grade of apical vertebral rotation was significantly correlated with scoliosis progression (regression coefficient=0.502, p=0.009).
Conclusion: Apical vertebral rotation may help predict the scoliosis progression and determine the timing of surgical intervention in patients with early degenerative lumbar scoliosis.