Measurement of Spinopelvic Parameters on Standing Lateral Lumbar Radiographs: Validity and Reliability.

Abstract

This was a radiographic validity and reliability study. We assessed the validity and reliability of measurements made on standing lateral lumbar radiographs, compared with lateral whole-spine radiographs, for evaluating spinopelvic parameters and lumbar lordosis (LL). A lateral whole-spine radiograph is the gold standard image for measurement of spinopelvic parameters. However, little evidence is available on the reliability of measurements made on such radiograph. A standing lateral lumbar radiograph is routinely obtained from patients with back pain and/or a disability. This image can include upper end plate of L1 vertebra, sacral dome and both femoral heads. Thus, this radiograph can be used for evaluation of spinopelvic parameters. We randomly selected 50 sets of digital radiographs (standing lateral lumbar and lateral whole-spine radiographs) from our database. Three experienced spinal surgeons independently measured LL, pelvic incidence, pelvic tilt, and sacral slope on all images. A paired t test and Pearson correlation was used to analyze the validity of the lateral lumbar radiograph. Interobserver and intraobserver reliabilities were assessed by intraclass correlation coefficient. Thee spinopelvic parameters and LL measured on lateral lumbar radiographs were similar to those measured on lateral whole-spine radiographs (All P-values >0.05, Pearson correlation coefficients, 0.807-0.969). The intraobserver and interobserver reproducibilities of both measurement types were good-to-excellent. Spinopelvic parameters and LL values measured on lateral lumbar radiographs were reproducibly similar to those measured on lateral whole-spine radiographs. Use of a standing lateral lumbar radiograph is reasonable when spinopelvic parameters and LL are to be measured.