Comparison of spinal sagittal parameters by time of day in a healthy working population: Do we bend during the day?

BACKGROUND: Prospective study. OBJECTIVE: To determine the change in spinal sagittal parameters which may occur throughout the day in healthy population. METHODS: Thirty-five healthy hospital employees were enrolled in the study. Two standing left lateral orthoroentgenograms were obtained at 8.00 a.m and at 6.00 p.m. Six spinopelvic parameters were measured on the X-rays. Thereafter, the subjects were divided into two cohorts according to their BMI as low BMI and high BMI. RESULTS: Thirty-five subjects with a mean age of 25.97 ± 8.21 were evaluated. No significant change was found between morning and evening measurements for any of the parameters. Direct relationship was shown between thoracic kyphosis (TK) and lumbar lordosis (LL), lumbar lordosis and sacral slope (SS), pelvic tilt (PT) and pelvic incidence (PI) minus lumbar lordosis, sagittal vertebral axis (SVA) and pelvic incidence minus lumbar lordosis. In addition an inverse relationship was found between sacral slope and pelvic tilt, sacral slope and pelvic incidence minus lumbar lordosis, thoracic kyphosis and pelvic incidence minus lumbar lordosis, sacral slope and pelvic tilt, sagittal vertebral axis and lumbar lordosis (p< 0.05). Sagittal vertebral axis were found to be higher in the high BMI group, and daily change was lower but the differences were not statistically significant. Only the change in pelvic tilt value was found to be statistically significant in low BMI group. CONCLUSION: Routine workload in a hospital environment does not cause significant change in the spinopelvic parameters throughout the day.