Changes in scoliotic curvature and lordotic angle during the early phase of degenerative lumbar scoliosis.

STUDY
DESIGN: Longitudinal radiographic measurements of the lumbar alignment in clinical cases were performed.
OBJECTIVE: To clarify the progressive process of degenerative lumbar scoliosis during its early phase by conducting a longitudinal study. SUMMARY OF BACKGROUND DATA: Previous studies on the alignment changes of degenerative lumbar scoliosis have been conducted only on patients with seriously symptomatic lumber scoliosis, such as those who have undergone surgical treatment. With these patients, who manifest wedging at several levels, it is difficult to determine where the curving initially begins, and to understand the wedging process. Thus, there is much to clarify regarding the process of this symptom's early phase. Furthermore, such data may be useful in anticipating future symptoms.
METHODS: The subjects selected for this study were 243 patients who had low back pain without lumbar scoliosis at the initial examination, which took place between 1985 and 1989. Anteroposterior and lateral radiographic examinations of the lumber spine were performed with the subject in a standing position. All of these patients went through at least three sets of examinations. The Cobb method was used to measure the scoliotic angle, defined as the largest angle between any two lines of the lumbar vertebrae. The 47 subjects who manifested a scoliotic angle increase exceeding 10 degrees were reselected for further prospective analyses. The scoliotic and lordotic wedging of these remaining 47 subjects were studied prospectively.
RESULTS: The degree of change in scoliotic and lordotic wedging was studied in the 47 patients who manifested a scoliotic angle increase of 10 degrees or more. Of the 47 subjects, 8 showed initial wedging at L1-L2, 9 at L2-L3, 7 at L3-L4, 10 at L4-L5, and 16 at L5-S. During later examinations, 69 discs of 34 patients showed initial wedging exceeding 3 degrees, both in progression and retrogression. On the other hand, changes in the segmental lordotic wedging also were observed during these examinations. Of the 79 discs that showed more than a 5 degrees decrease in segmental lordotic wedging, progression of scoliotic wedging at the same level was observed in 56 cases, either simultaneously or at previous examinations.
CONCLUSIONS: Degenerative lumbar scoliosis was triggered by any disc degeneration at the lumbar level. Loss of segmental lordosis usually occurs at the same disc level as segmental wedging. In the early phase of degenerative lumbar scoliosis, the scoliotic curvature not only progresses, but also may retrogress.