We have seen prior studies highlight the significant association between sagittal alignment and patient reported outcome measures (PROMS) among adult spinal deformity patients, particularly the C7 SVA and PI-LL mismatch and their influence on patient related outcome measures. Recently, however, there has been an increased focus on incorporating measures that account for the cranium and lower extremities to assess total body sagittal alignment. Thus, the cranial sagittal vertical axis (CrSVA) has been used as a novel parameter to measure the horizontal distance to the vertical plumb line from the nasion-inion midpoint to reference points at the sacrum, hip, knee, and ankle. Preliminary analyses have shown its significance its association with preoperative PRO MS, but there’s a scarcity of data on how this parameter correlates with other measures of global alignment,
especially at the 2yr postoperative time point.

In our newly published study, we validated the CrSVA to be a significant driver of PROMS with the CrSVA to the hip a stronger predictor than the C7 SVA at 2yrs postop. Thus, we recommend the CrSVA, particularly the position of the cranium relative to the hips, as one of the standard postoperative standard sagittal alignment goals for ASD patients.