Selective thoracic fusion provides similar health-related quality of life but can cause more lumbar disc and facet joint degeneration: A comparison of adolescent idiopathic scoliosis patients with normal population 10 years after surgery

Abstract

Objectives To evaluate the long-term behavior of the lumbar curve in patients with adolescent idiopathic scoliosis treated with selective thoracic fusion and to assess the clinical and radiologic outcomes in this fusion group compared with an age- and gender-matched group. Summary of Background Data Selective thoracic fusion for the treatment of adolescent idiopathic scoliosis (AIS) preserves lumbar motion segments but leaves a residual deformity. By avoiding fusion of the lumbar spine, a greater mobility may be preserved, which may be an advantage in long-term follow-up in terms of degenerative changes in unfused segments. Methods Group A included 25 AIS patients with mean a age of 23.8 years and a mean 11.4 years of follow-up. Group B included 30 age- and gender-matched subjects without any deformity. Preoperative, postoperative, and follow-up radiographs were reviewed. All patients had MRIs taken at the final follow-up in order to evaluate disc degeneration (DD) and facet joint degeneration (FJD) at the unfused lumbar spine. Clinical evaluation was done by using Scoliosis Research Society-22R, Oswestry Disability Index, and numerical rating scale. Results Sagittal and coronal balance and lowest instrumented vertebra disc angulation were stable over time. Mean grading of lumbar DD was 2.16 (2-4) in Group A and 1.86 (1-3) in Group B. Lumbar FJDs were 2.05 (1-4) in Group A and 1.60 (1-3) in Group B. There was significant difference between the two groups for DD except for the L4-L5 level (p =.26). FJD was significantly higher in the L1-L2 and L2-L3 levels (L1-L2, p =.002, L2-L3, p =.002) but not for the other levels. Outcome scores were similar without significant differences between the two groups (p >.05). Conclusion Selective thoracic fusion provides satisfactory outcomes at more than 10 years of follow-up. Our study demonstrated a moderate increase in the rate of disc degeneration in the unfused segments. Facet joint degeneration was significant at the upper two levels adjacent to the lowest instrumented vertebra. © 2015 Scoliosis Research Society.