Relationship between Intervertebral Disc Compression Force and Sagittal Spinopelvic Lower Limb Alignment in Elderly Women in Standing Position with Patient-Specific Whole Body Musculoskeletal Model

The intervertebral disc loading based on compensated standing posture in patients with adult spinal deformity remains unclear. We analyzed the relationship between sagittal alignment and disc compression force ([Formula: see text]). In 14 elderly women, the alignment of the sagittal spinopelvic and lower extremities was measured. [Formula: see text] was calculated using the Anybody Modeling System. Patients were divided into low sagittal vertical axis (SVA) and high SVA groups. Comparisons between the two groups were performed and the relationship between the [Formula: see text] and each parameter was examined using Spearman’s correlation coefficient (r). The mean lumbar [Formula: see text] in the high SVA group was 67.6%; significantly higher than that in the low SVA group (p = 0.046). There was a negative correlation between cervical [Formula: see text] with T1 slope (r = −0.589, p = 0.034) and lumbar [Formula: see text] with lumbar lordosis (r = −0.566, p = 0.035). Lumbar [Formula: see text] was positively correlated with center of gravity-SVA (r = 0.615, p = 0.029), T1 slope (r = 0.613, p = 0.026), and SVA (r = 0.612, p = 0.020). The results suggested sagittal malalignment increased the load on the thoracolumbar and lower lumbar discs and was associated with cervical disc loading.