Trends of the Oswestry Disability Index in Adult Spinal Deformity Patients: A 3-Year Study.

BACKGROUND: and Importance: Patients with adult spinal deformity (ASD) undergoing operative treatment may have varying degrees of improvement in patient-reported outcomes. The Oswestry Disability Index (ODI) assesses improvement in quality of life. We aim to measure longitudinal outcomes of ODI scores over three years to determine if early ODI scores predict late ODI scores and to analyze longitudinal changes in ODI scores.

METHODS: 235 patients above the age of 18 who underwent surgical correction of ASD at a single institution from 2016 to 2021 and completed ODI questionnaires at follow-up appointments met inclusion criteria. ODI scores were included from follow-up visits at 0 months (immediately postoperative) and within ±1 month of 3, 6, 12, 18, 24, 30, and 36 months. Percent change in ODI from 0 months was calculated, and unpaired t-tests were conducted.

RESULTS: ODI scores increased by 8.8% immediately postoperatively, and the percent change from preoperative ODI scores at each subsequent visit were as follows: -11.1% at 3 months, -21.4% at 6 months, -25.4% at 12 months, -28% at 18 months, -31.3% at 24 months, -25.7% at 30 months, and -36.5% at 36 months. ODI scores at each follow-up visit showed significant improvement from baseline (p<0.001). There was an improvement in scores from 3 to 6 months (p=0.04), but no significant difference in 6-month interval visits following 6 months.

CONCLUSION: Our results demonstrate a significant and sustained improvement in ODI scores over 3 years following surgical correction of ASD. ODI scores were stable after 6 months, indicating that ODI scores at 6 months may be predictive of scores out to 3 years postoperatively. Examining individual components of ODI sub-scores and comparing ODI results to other PROMs are critical to better assess long-term outcomes in ASD.