The changes in sagittal alignment of spine from standing to sitting position in elderly people

English Keywords:Sagittal alignment  Position change  Elder persons

English Abstract:

  【Abstract】 Objectives: To explore how the sagittal alignment of spine change in elderly people from standing position to sitting position and compare these changes with that of normal young Chinese adults. Methods: The data of 53 elder persons(17 males, 36 females; mean age, 60.7±9.3 years) and 145 young adults (51 males, 94 females; mean age, 23.1±2.3 years) that underwent physical examination in Peking University Third Hospital were retrospective reviewed. All of them underwent the full-spine X-ray scan in standing and sitting position. Pelvic and spinal parameters were measured by Picture Archiving and Communication System, including pelvic incidence(PI), pelvic tilt(PT), sacral slope(SS), lumbar lordosis(LL), thoracic kyphosis(TK), spinosacral angle(SSA), lordosis tilt(LT), sagittal vertical axis(SVA) and T1-pelvic angle(T1PA). The parameters in different positions were compared using paired t test, and the changes from standing to sitting between elder persons and young adults were compared using independent t test. Results: For elder persons, SVA was 3.9±27.7mm in standing position. TPA, PT, SSA, LL, LT, TK and SS was 8.5°±6.9°, 12.7°±7.2°, 124.3°±9.0°, 47.2°±12.1°, -6.0°±6.9°, 33.2°±8.7° and 32.8°±8.2°, respectively. While in sitting position, SVA was 25.9±26.0mm, TPA, PT, SSA, LL, LT, TK and SS was 18.1°±8.5°, 21.1°±9.5°, 113.6°±10.3°, 33.8°±12.9°, -4.4°±5.7°, 28.5°±9.7° and 25.1°±9.2°, respectively. There were statistical differences(P<0.05) except LT. Changing from standing position to sitting position, SVA increased 22.0±32.6mm, TPA, PT and LT increased 9.6°±6.2°, 8.4°±7.3° and 1.5°±6.2°, respectively; LL, TK, SS and SSA decreased 13.4°±8.8°, 4.6°±5.0°, 7.6°±7.2° and 10.7°±8.1°, respectively. Compared with the young adults, elder persons showed smaller increase in SVA, TPA, PT, LT and smaller decrease in LL, TK, SS when moving from standing to sitting position. Conclusions: When changing from standing position to sitting position, the spine of elder persons went forwards, accompanied with straighter sagittal curve, pelvic retroversion and kyphosis, yet their spine-pelvic sagittal alignment was significantly less affected by body position than young adults.