Spinopelvic changes based on the simplified SRS-Schwab adult spinal deformity classification: relationships with disability and health-related quality of life in adult patients with prolonged degenerative spinal disorders

Study Design. Cross-sectional, observational study. Objective. To study the occurrence of sagittal malalignment, the adaptability of a simplified sagittal modifiers grading of the Scoliosis Research Society (SRS)-Schwab adult spinal deformity (ASD) classification, and the deformity-specific SRS questionnaire version 30 (SRS-30) in an unselected adult cohort with symptomatic degenerative spinal disorders. Summary of Background Data. The sagittal modifiers of the SRS-Schwab ASD classification correlate with health-related quality of life (HRQoL) measures in patients with ASD. The deformities and disabilities caused by sagittal malalignment in patients with common degenerative spinal disorders of multiple etiologies are rarely studied. A simplified and categorizing version of the SRS-Schwab ASD classification in relation to the Oswestry Disability Index (ODI) and the SRS-30 outcomes has not yet been developed. Methods. We recruited 874 consecutive patients with degenerative spinal disorders between March 2013 and February 2014. Full spine radiographs were taken and the patients divided into sagittal deformity severity groups: mild or none, moderate, and marked deformity. Participants completed the ODI, SRS-30, and a general health questionnaire. Results. We included 637 patients in the analysis. The severity of sagittal deformity was mild or none in 407 (63.9%) patients, moderate in 159 (25.0%), and marked in 71 (11.1%). Linearity across the modifier grades and deformity classes was found for ODI total score (P ¼ 0.033), and the function/activity (P ¼ 0.004) and self-image/appearance (P¼ 0.030) domains of the SRS-30. Age, body mass index, duration of symptoms, and the use of painkillers increased while physical activity, working, and educational status decreased significantly with deformity severity. Conclusion. Sagittal spinopelvic malalignment is significantly related to deterioration of the ODI and the SRS-30 in symptomatic adults with degenerative spinal disorders. The SRS-Schwab classification sagittal modifiers categorized into three groups is a practical tool to detect various clinically significant grades of deformity in a cohort with no recognized ASD.