Spinal posture and pelvic position during pregnancy: a prospective rasterstereographic pilot study.

PURPOSE: Despite the high prevalence of low back pain during pregnancy there is still a lack in the understanding of its aetiology. Changes of the spinal posture due to the anatomical changes of the pregnant body seem to be in part responsible for the back pain. In this pilot study we assessed the potential to accurately measure the spinal posture and pelvic position during pregnancy without any harmful radiation using a spine and surface topography system. METHODS: Thirteen pregnant women were examined during the second and third trimester of their pregnancy, and postpartum. Twenty female, non-pregnant volunteers comprised the control group. The spinal posture and pelvic position were measured with a radiation-free spine and surface topography system. RESULTS: We found a significant increase in thoracic kyphosis during the course of pregnancy, but no increased lumbar lordosis. The lateral deviation of the spine also decreased significantly. However, we did not measure significant changes of the pelvic position during or after pregnancy. CONCLUSIONS: The results of our study show that pregnancy has an effect on the spinal posture, and that spine and surface topography can be used to measure these changes three-dimensionally and without any harmful radiation. In future studies this technique could allow to further evaluate the relationship between posture and low back pain during pregnancy, helping to understand the aetiology of low back pain in pregnancy as well as to identify methods for its prevention and treatment.

Influence of foot positions on the spine and pelvis.

OBJECTIVE: The management of knee osteoarthritis includes the use of wedged shoe insoles to unload the affected knee compartment. Although the biomechanical effects of shoe insoles on the knee joint are known and described, only little is known about their influence on the pelvis and spine. Therefore, the purpose of this study was to evaluate the effects of different foot positions, such as how they could be achieved by shoe insoles, on pelvic position and spinal posture. METHODS: A total of 51 test subjects were measured for this study. The different foot positions (inner and outer margin increase, positive and negative heel height) were simulated with a specially designed stand platform. A rasterstereographic device was used to measure the immediate effects of the simulated foot positions on the pelvic position and spinal posture. RESULTS: Positive and negative heel heights as well as an increase of the outer margin of the platform led to significant changes of the pelvic tilt. The pelvic torsion also changed significantly during positive heel height changes of 10 and 15 mm and increases of the outer margin of the foot. No significant changes were found between foot position and spinal parameters. CONCLUSION: The results of our study support the existence of a kinematic chain, where changes of foot position also led to significant alterations of the pelvic position. Whether these changes could lead to long-term pathologic alterations still needs to be evaluated. However, in our setting, no correlation between foot position and spinal posture changes was found.