This inter- and intra-rater reliability study validates the SRS-Schwab adult spinal deformity (ASD) classification. The system grades patients by coronal curve type (T, L, D, N) plus three sagittal modifiers (PI-LL, PT, SVA), with modifier thresholds derived from HRQOL outcome data. Nine spine surgeons graded 21 premarked radiographic cases twice to confirm consistency of the classification.
Management of adult spinal deformity is driven by pain and disability, not radiographic deformity magnitude alone — yet prior classification systems lacked validated sagittal and pelvic parameters tied to patient-reported outcomes.
When you evaluate an adult deformity patient, the SRS-Schwab system gives you a reproducible language: assign a curve type (T/L/D/N), then grade each of the three sagittal modifiers. A PI-LL mismatch above 11°, PT above 22°, or SVA above 46 mm each signals clinically significant disability (ODI ≥40) and changes your surgical planning.
High PT deserves particular attention. It is a compensatory mechanism that can make sagittal malalignment look better than it is on a standing film. A patient with a "normal" SVA but a PT of 30° is compensating hard, and you need to account for that when planning osteotomy magnitude.
The system's reliability was confirmed across 9 surgeons and improves with familiarity, making it practical for daily use and multicenter outcome comparisons.
This inter- and intra-rater reliability study validates the SRS-Schwab adult spinal deformity (ASD) classification. The system grades patients by coronal curve type (T, L, D, N) plus three sagittal modifiers (PI-LL, PT, SVA), with modifier thresholds derived from HRQOL outcome data. Nine spine surgeons graded 21 premarked radiographic cases twice to confirm consistency of the classification.
Management of adult spinal deformity is driven by pain and disability, not radiographic deformity magnitude alone — yet prior classification systems lacked validated sagittal and pelvic parameters tied to patient-reported outcomes.
When you evaluate an adult deformity patient, the SRS-Schwab system gives you a reproducible language: assign a curve type (T/L/D/N), then grade each of the three sagittal modifiers. A PI-LL mismatch above 11°, PT above 22°, or SVA above 46 mm each signals clinically significant disability (ODI ≥40) and changes your surgical planning.
High PT deserves particular attention. It is a compensatory mechanism that can make sagittal malalignment look better than it is on a standing film. A patient with a "normal" SVA but a PT of 30° is compensating hard, and you need to account for that when planning osteotomy magnitude.
The system's reliability was confirmed across 9 surgeons and improves with familiarity, making it practical for daily use and multicenter outcome comparisons.