Sagittal alignment of spine and pelvis regulated by pelvic incidence: standard values and prediction of lordosis

Pelvis and spinal curves were studied with an angular parameter typical of pelvis morphology: pelvic incidence. A significant chain of correlations between positional pelvic and spinal parameters and incidence is known. This study investigated standards of incidence and a predictive equation of lordosis from selective pelvic and spinal individual parameters. One hundred and forty nine (78 men and 71 women) healthy adults, aged 19-50 years, with no spinal disorders, were included and had a full-spine lateral X-ray in a standardised upright position. Computerised technology was used for the measurement of angular parameters. Mean-deviation section of each parameter and Pearson correlation test were calculated. A multivariate selection algorithm was running with the lordosis (predicted variable) and the other spinal and pelvic parameters (predictor variables), to determine the best sets of predictors to include in the model. A low incidence (<44 degrees ) decreased sacral-slope and the lordosis is flattened. A high incidence (>62 degrees ) increased sacral-slope and the lordosis is more pronounced. Lordosis predictive equation is based on incidence, kyphosis, sacral-slope and +/-T9 tilt. The confidence limits and the residuals (the difference between measured and predicted lordosis) assessed the predicted lordosis accuracy of the model: respectively, +/-1.65 and 2.41 degrees with the 4-item model; +/-1.73 and 3.62 degrees with the 3-item model. The ability of the functional spine-pelvis unit to search for a sagittal balance depended both on the incidence and on the variation section of the other positional parameters. Incidence gave an adaptation potential at two levels of positional compensation: overlying state (kyphosis, T9 tilt), underlying state (sacral slope, pelvic tilt). The biomechanical and clinical conditions of the standing posture (as in scoliosis, low back pain, spondylisthesis, spine surgery, obesity and postural impairments) can be studied by comparing the measured lordosis with the predicted lordosis.

Geometric and postural analysis of mild idiopathic scoliotic patients

Understanding the aggravation process of mild idiopathic scoliosis is still a challenge. The aim of this study is to investigate the spine and pelvis configuration with regard to gravity line using 3D reconstruction coupled with foot pressure measurements. The distance between each vertebral center and the gravity line is calculated in order to observe the global equilibrium of spine. A protocol has been set and used for 10 mild idiopathic scoliotic patients. 34 asymptomatic volunteers who were previously observed with the same protocol were used as reference for biomechanical comparisons. The first results showed differences between scoliotic and asymptomatic subjects and also among scoliotic patients. The proposed protocol should allow clinicians to follow up scoliotic patients with an innovative and efficient tool.

Bone mineral density at the femur and lumbar spine in a population of young women treated for scoliosis in adolescence

OBJECTIVES

To evaluate associations between scoliosis and bone mineral density. Many of the factors involved in the etiopathogenesis of idiopathic scoliosis also affect peak bone mass acquisition, which occurs primarily during puberty, a period of progression for scoliosis.

METHOD

We compared 33 patients treated for scoliosis with 33 controls and looked for correlations between bone mineral density and a number of retrospectively collected parameters (e.g., duration of bracing, outcome in adulthood).

RESULTS

Bone mineral density values were lower in the patients than in the controls. Among the patients, those with osteopenia wore a brace significantly longer and had more severe scoliosis in adulthood than those without osteopenia.

CONCLUSIONS

These findings suggest a need for osteopenia screening and prevention in children with scoliosis, for monitoring physical activity and calcium intake during bracing, for preferring braces that allow greater mobility, and for closely monitoring the scoliosis during adulthood if osteopenia is present.

[The use of an original brace in the treatment of kyphosis (author's transl)]

The authors have designed an original brace which can be used in the treatment of severe and evolutive hyphosis, when kinesitherapy alone is not sufficient. The brace can be removed during the night and for the practice of sports. It is based on the increase of corrective reflexes. A review of 100 cases showed satisfactory results.