Dissecting the Effects of Spinal Fusion and Deformity Magnitude on Quality of Life in Patients With Adolescent Idiopathic Scoliosis

STUDY DESIGN: A retrospective review of scores from the Scoliosis Research Society outcomes instrument (SRS-24 questionnaire). OBJECTIVE: To quantify the isolated effects of spinal fusion and deformity magnitude on quality of life in patients with adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: Significant improvements in 2-year postoperative SRS-24 questionnaire scores have been reported despite the loss of spinal motion due to instrumentation and arthrodesis. As deformity reduction may influence patient perception, it has been difficult to isolate the effect of spinal fusion on quality of life after scoliosis surgery. METHODS: SRS-24 scores were compared between 3 cohorts of AIS patients (preoperative, postoperative, and nonoperative) using an ANOVA (P < 0.05) to determine the isolated effects of spinal fusion and deformity magnitude. Preoperative SRS-24 scores were collected from a group of patients with preoperative major Cobb angles greater than 40 degrees (n = 194). Postoperative SRS-24 scores were collected from patients with preoperative major Cobb angles greater than 40 degrees and 2-year postoperative major Cobb angles between 20 degrees and 40 degrees (n = 196). Finally, SRS-24 scores were collected from a nonoperative group of patients with major Cobb angles between 20 degrees and 40 degrees (n = 112). RESULTS: Spinal fusion was found to have a negative isolated effect on the Activity domain (-0.3) and on the Total score (-0.2) (P = 0.001) of the SRS-24 questionnaire (score range: 1-5). A smaller deformity magnitude, on the other hand, was found to have a significantly positive isolated effect on all 4 preoperative domains (P < 0.001) and on the Total score (P < 0.001). The combined effect of surgery (spinal fusion and deformity correction) was found to be significantly positive for the Total score (P < 0.001) and for the domains of Pain, Self-Image, and Function (P < 0.001). CONCLUSION: Spinal fusion has an isolated negative effect on AIS patients' quality of life (Total score) mostly due to a decrease in scores of the Activity domain. The overall positive effect of surgery depends on the individual effects of spinal fusion (slight reduction in quality of life) and deformity reduction (modest improvement in quality of life).