Photographic sagittal plane analysis and its clinical correlation after surgery for adult spinal deformity: a preliminary study

Purpose The aim of this study is to determine the correlation between photographic sagittal parameters and patient-reported outcome measures (PROM) results in adult patients operated on spinal deformity. Methods Non-concurrent prospective study. Inclusion criteria: age at surgery older than 25, minimum 2-year follow-up after a 5 or more level fusion for adult spinal deformity (ASD). Full body lateral standing photographs were taken with adhesive markers placed on ten bony landmarks. SRS-22 and SF-36 questionnaires were completed for every patient. The following photographic parameters were measured: lumbar angle, lumbar curve, thoracic inclination (TI), trunk angle, pelvic tilt, head angle, neck angle, cervicothoracic angle, lumbar vector angle (LVA), dorsal vector angle (DVA), cervical vector angle (CVA), cranial pelvic angle (CrPA), cranial sacral angle (CrSA), fibular inclination angle (FIA) and cranial sagittal vertical axis measured to sacrum (Cr-S), greater trochanter (Cr-GT), knee (Cr-K) and ankle (Cr-A). Results 65 patients (58 female) operated on ASD in a single institution were included. Age at surgery was 61 years (26–67). Postoperative follow-up was 53 months (24–120). Spearman rank order test showed several significant ( p ≤ 0.01) correlations. After multivariate linear regression analysis age, LVA and TI remained as predictors for SRS image scores (corrected r 2 0.41), LVA for SRS satisfaction (corrected r 2 0.27), CrPA and age for SRS total scores (corrected r 2 0.33), FIA and age for SF36 physical functioning (corrected r 2 0.36) and CrSA for SF36 role physical (corrected r 2 0.14). Conclusions Some sagittal photographic parameters may predict mid-term clinical results after ASD surgery.