Introduction: ASD has traditionally been described using pediatric classifications that neglect sagittal spinopelvic parameters. Our hypothesis was that the Schwab–SRS classification, a validated system to classify ASD, will be responsive to and predict changes in HRQOL measures from baseline to 1 yr follow-up for operatively (OP) and nonoperatively (NONOP) treated ASD patients.
Methods: Multicenter, prospective, consecutive case series. Inclusion criteria: ASD, age>18, baseline and min 1 yr x-rays and HRQOL measures (Oswestry Disability Index [ODI], SRS-22 and SF-36). The Schwab-SRS classification includes 3 sagittal modifiers, each with 3 grades (normal, moderately poor and poor). These modifiers are sagittal vertical axis (SVA: <4, 4-9 or >9cm), pelvic tilt (PT: <20, 20-30 or >30°), and pelvic incidence/lumbar lordosis mismatch (PI-LL: <10, 10-20 or >20°). Changes in modifiers at 1 yr were assessed for impact on HRQOL from pre-treatment values.
Results: 391 patients met criteria (mean age=54 yrs; 85% women; OP, n=189; NONOP, n=202). Change in SVA modifier at 1 yr was associated with changes in ODI, SF36 physical component score (PCS) and SRS-22 total and all subscores (p<0.03), but not the SF-36 mental component score (MCS). Change in PI-LL modifier at 1 yr was associated with changes in SF-36PCS, SRS-22 total score and 4 of the SRS-22 subscores (p<0.03). Changes in SVA and PI-LL modifiers were associated with likelihood of achieving minimal clinical important difference for ODI and SRS subscores (p<0.03). Changes in PT modifier were not significantly associated with changes in HRQOL measures.
Conclusions: The Schwab-SRS classification of ASD provides a validated language and has significant association with HRQOL measures. The current study demonstrates that the classification modifiers are responsive to changes in disease state and reflect significant changes in patient reported outcomes.
Patient Care: This research improves patient care by demonstrating that the recently proposed Schwab-SRS classification system for adult spinal deformity is responsive to changes in disease state and reflects significant changes in patient reported outcomes.
Learning Objectives: By the conclusion of this presentation, participants should: 1) appreciate that The Schwab-SRS classification of adult spinal deformity (ASD) provides a validated method to describe ASD and correlates with baseline health-related quality of life (HRQOL) measures and 2) appreciate that the Schwab-SRS classification is responsive to changes in disease state and can be used to predict treatment outcomes based on ASD patients changes in classification modifiers following operative or nonoperative treatment.