Intervertebral Disc Degeneration During Postoperative Follow-up More Than 10 Years After Corrective Surgery in Idiopathic Scoliosis: Comparison Between Patients With and Without Surgery.

STUDY DESIGN: A retrospective comparative study.

OBJECTIVE: The aim of this study was to evaluate the difference in trends of disc degeneration (DD) at lower unfused segments (LUS) for postoperative patients who have gone through spinal instrumentation at 10-year follow-up with the natural progression of idiopathic scoliosis.

SUMMARY OF BACKGROUND DATA: Studies that used magnetic resonance imaging (MRI) state that DD rates at LUS are higher than in the normal population. However, current studies do not prove that surgery is the most effective clinical method to treat idiopathic scoliosis, as no existing report compares the rates of DD with the natural history of idiopathic scoliosis.

METHODS: Female patients diagnosed of scoliosis were divided into three groups: 1) surgical group: postoperative 10-year patients with severe scoliosis before operation; 2) mild scoliosis group: with comparatively equal scoliosis to postoperative patients of the same age at 10 years follow-up; 3) severe scoliosis group: without any record of corrective surgery under the assumption that the scoliosis of the surgical group have progressed according to natural history.

RESULTS: MRI findings of the surgical group show DD in 32 patients (62.7%) where the highest rate of DD occurred at L5/S. In the mild scoliosis group, 21 patients (47.7%) had DD, with higher rates at L4/5 and L5/S. DD was most common in L3/4 and L4/5 in the severe scoliosis group where 27 patients (81.8%) had DD. As such, DD rates were significantly higher in the severe scoliosis group than the surgical group at the same spinal level. The same was true for the existence of low back pain, where the severe scoliosis group had greater incidence of low back pain than the surgical group.

CONCLUSION: Corrective surgeries were able to reduce the incidence of DD. Radiological analysis also suggests that surgical intervention is a clinically feasible treatment for idiopathic scoliosis patients.

LEVEL OF EVIDENCE: 3.