Do 1-year outcomes predict 2-year outcomes for adult deformity surgery?

Background Context: Health-related quality-of-life (HRQOL) measures are being used more frequently in the evaluation of the adult deformity patient. This is due in part to the validation of the deformity-specific Scolios Research Society-22 (SRS-22). Hence, relationships between HRQOL outcomes and traditional measures of success such as deformity correction, fusion healing, and complications are being established. Purpose: To examine the pattern of HRQOL outcome responses after adult deformity surgery. Study design: Analysis of prospective multicenter cohort. Patient sample: Two hundred and eighty-three adult deformity patients with preoperative, 1-, and 2-year postoperative outcome measures. Outcome measures: SRS-22, Short Form-12 (SF-12), Oswestry Disability Index (ODI), and back and leg pain numeric rating scale scores. Methods: Preoperative versus postoperative health status measures were evaluated by matched-pairs sample t test statistics and post hoc analysis of variance (ANOVA) findings. Results: SRS-22 improved from a mean 3.03 points at baseline to 3.21 points at 6 months, 3.71 points at 1 year, and 3.70 points at 2 years post-op. Mean ODI score was 37.0 points pre-op and improved to 27.0 points at 6 months, and 22.8 points at 1 and 2 years post-op. Mean SF-12 physical component score was 33.7 points at baseline, improving to 36.9 points at 6 months, 40.6 points at 1 year, and 40.5 points at 2 years post-op. Paired samples analysis comparing 6-month and 1-year post-op scores showed deterioration for numeric rating scale leg pain (p=0.05). There was a trend for improvement in SF-12 physical component score (p=0.06). Significant improvement between 6 months and 1 year post-op was noted for ODI (p=0.02) and SRS total score (p<0.0001). Comparison of 1- versus 2-year postoperative scores revealed no statistically significant differences for any of the HRQOL parameters. Conclusions: This study supports the application of HRQOL measures, including the deformity-specific SRS-22, as a valuable tool in the assessment of adult deformity patients. Change in outcome score stabilized after the 1-year postoperative interval, for most patients.