SRS-Schwab classification

Adult spinal deformity

Coronal Curve Types

T: Thoracic only

with lumbar curve < 30°

L: Thoracolumbar (TL) / Lumbar only

with thoracic curve < 30°

D: Double Curve

with T and TL/L curves > 30°

N: No Major Coronal Deformity

all coronal curves < 30°

Sagittal Modifiers

PI-LL (Pelvic Incidence minus Lumbar Lordosis) 

  0: non pathologic (PI-LL < 10°)
  
  +: moderate deformity (PI-LL 10° - 20°)
  
  ++: marked deformity (PI-LL > 20°)

Global Alignment

(SVA = sagittal vertical axis) 

  0: non pathologic (SVA < 4cm)
  
  +: moderate deformity (SVA 4-9.5cm)
  
  ++: marked deformity (SVA > 9.5cm)

Pelvic Tilt (PT) 

  0: non pathologic (PT < 20°)
  
  +: moderate deformity (PT 20° - 30°)
  
  ++: marked deformity (PT > 30°)

1).

1)
Terran J, Schwab F, Shaffrey CI, Smith JS, Devos P, Ames CP, et al. The SRS-Schwab Adult Spinal Deformity Classification. Neurosurgery. 2013 Oct;73(4):559-68.