Criteria to restore the sagittal balance in deformity Eur Spine J (2012) 21 (Suppl 1):S27–S31

Purpose To present in a single source the relevant
information needed to assess spinopelvic balance and
alignment, and to estimate the amount of correction needed
in a patient during surgical treatment.
Methods Narrative literature review
Results Sagittal balance can be evaluated by global balance
estimates (sagittal vertical axis and T1 tilt). Other
important parameters are the relationship between pelvic
incidence and lumbar lordosis (spinopelvic harmony),
between pelvic incidence and difference of thoracic
kyphosis and lumbar lordosis (spinopelvic balance), excess
of pelvic tilt, knee flexion and thoracic compensatory
hypokyphosis. Different methods to calculate the amount
of surgical correction needed in patients with sagittal
imbalance have been based on combinations of these
parameters.
Conclusions Relevant parameters of sagittal imbalance
have been identified and correlated with clinical outcomes.
Methods for calculation of surgical correction of imbalance
have been proposed, but not validated in patients with midterm
follow-up.