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Sagittal Balance Parameters

Spinal Deformity

A 62-year-old woman presents with progressive lower back pain and difficulty standing upright. She leans forward when walking and uses her hands on her thighs for support. Standing full-spine radiographs show: pelvic incidence (PI) 55°, lumbar lordosis (LL) 25°, pelvic tilt (PT) 32°, and sagittal vertical axis (SVA) +12cm. She has no neurological deficits. Regarding sagittal balance assessment:

Mark each as TRUE or FALSE

A

Pelvic incidence (PI) is a fixed anatomical parameter measured as the angle between a line perpendic...

B

The PI-LL mismatch in this patient is 30° (PI 55° minus LL 25°); ideal alignment requires PI minus L...

C

Pelvic incidence changes with posture and can be modified by exercise; SVA of +12cm is within normal...

D

SVA (C7 plumb line to posterosuperior corner of S1) greater than 5cm correlates with increased disab...

E

The equation PI = PT + SS is a geometric relationship where sacral slope (SS) measures sacral inclin...

Answer the questions to see explanations

Click T (True) or F (False) for each option