Study on spinal sagittal alignment at standing and sitting position in patients with non-specific low back pain

English Keywords:Non-specific low back pain  Sitting-standing position  Spinal sagittal alignment

English Abstract:

  【Abstract】 Objectives: To study the spinal sagittal alignment at standing and sitting positions in patients with non-specific low back pain (NLBP). Methods: 50 NLBP patients (15 males and 35 females; mean age 48.0±10.7 years) were included and 50 healthy volunteers (17 males, 33 females; mean age 45.2±10.6 years) were recruited as control group. Spinalmouse was used to measure the angles of thoracic kyphosis (TK), lumbar lordosis (LL), sacral inclination (SacHipJ) and inclination (Incl) of the two groups at sitting and standing positions respectively. Wilcoxon test was used to compare the differences of spinal parameters between sitting and standing positions in each group, and Mann-Whitney U test was used to compare the differences of the spinal parameters of the standing position, sitting position and the difference value(D) from standing to sitting positions between the two groups. Spearman test was used to analyze the correlation among visual analogue scale(VAS) of the low back pain and LL at sitting and standing position and D-LL in the NLBP group. NLBP group was divided into four age groups: 30-39 years old, 40-49 years old, 50-59 years old, and 60-69 years old, and Kruskal-Wallis H test was used to compare the differences of LL at sitting and standing position and D-LL at different ages in the NLBP group. Results: When the position was changed from standing to sitting, TK, LL and SacHipJ decreased(P<0.05) and Incl increased(P<0.05) in both groups. In standing position, there was no difference in angles between the two groups(P<0.05). In the sitting position, the LL was greater and the Incl was smaller(P<0.05) in NLBP group than those in the control group. When the position was changed from standing to sitting, the angle variation of TK, LL and Incl in NLBP group were smaller than those in control group(P<0.05). VAS had no correlation with LL at standing or sitting position(P>0.05), but there was a weak negative correlation with the D-LL(rs=-0.293, P<0.05) in the NLBP group. There was no statistically significant difference among LL at sitting and standing position or D-LL at different ages in the NLBP group(P>0.05). Conclusions: Spinal sagittal alignment at standing and sitting position in patients with NLBP was different from that of healthy people: the LL was greater than that of healthy subjects in the sitting position, and the variation of thoracic spine and lumbar spine flattening and trunk forward movement were smaller than those of healthy subjects in the shift from the standing position to the sitting position, except for the posterior rotation of pelvis.