Table 2.

Sagittal balance status classification

Status	Parameters of global sagittal spinal balance	Situation of compensatory mechanisms to regain sagittal balance
Sagittally balanced	SVA (sagittal vertical axis through center of C7 body) is within 5 cm from the posterior margin of the S1 endplate	Pelvic tilt is less than 1/3 of the pelvic incidence AND femoral shaft axis is vertical
Sagittally compensating	SVA (sagittal vertical axis through center of C7 body) is within 5 cm from the posterior margin of the S1 endplate	Increased pelvic tilt (pelvic tilt is less than 1/3 of pelvic incidence) OR femoral shaft axis IS NOT vertical (indicating compensatory knee flexion to increase pelvic tilt or translate center of mass)
Sagittally imbalanced	SVA (sagittal vertical axis through the center of the C7 body) is more than 5 cm from the posterior margin of the S1 endplate