A noninvasive anthropometric technique for measuring kyphosis and lordosis: an application for idiopathic scoliosis.

STUDY DESIGN: Cross-sectional measurement of the sagittal geometry of adolescent idiopathic scoliosis patients. OBJECTIVES: To evaluate the accuracy of a noninvasive anthropometric approach for the measurement of kyphosis and lordosis. SUMMARY OF BACKGROUND DATA: Noninvasive approaches were developed to estimate the sagittal curvatures of the spine. However, the magnitude of the estimation error could be high for an important proportion of patients, which leads to a difficult clinical application. METHODS: The group was composed of 124 female patients with a mean age of 13.5 years (SD 2. 7 years) with Cobb angles ranging from 4 degrees to 66 degrees. Kyphosis and lordosis were measured on the lateral radiograph. The spine sagittal curvature of the same patients was also estimated using the spatial localization of skin markers placed overlying the spinous processes. These coordinates served as input into a simple trigonometric model. Data were collected by means of a stereovideographic technique (Motion Analysis Corp., Santa Rosa, CA). RESULTS: The intraclass correlation coefficient between both approaches was 0.94 for kyphosis and 0.91 for lordosis; the mean absolute differences were 5 degrees (SD 4 degrees ) and 6 degrees (SD 6 degrees ), respectively. The difference was less than 10 degrees in 91% of the patients for kyphosis, and in 79% for lordosis. CONCLUSIONS: The proposed technique appears to give more representative results than those presented in the literature. It has the advantage of being part of a global noninvasive postural evaluation. Using this approach in a systematic manner could help reduce radiograph exposure while keeping track of the spine sagittal curvatures.

[Classification of left thoracolumbar scoliosis according to its radiologic morphology and its postural geometry]. / Classification des scolioses thoraco-lombaires gauches selon leur morphologie radiologique et leur géométrie posturale.

Idiopathic scoliosis is a tridimensional (3D) deformation of the spine associated with postural geometry (PG) disorganisation. Conventional classification of scoliosis is primarily based on the analysis of PA X-rays. This is a descriptive classification that forms heterogeneous groups. Diagnosis, prognosis and treatments are then developed around partial information. The goal of this project was to divide the left thoracolumbar (TLG) class in two subgroups using exhaustive analysis of the PA and lateral X-rays, and the evaluation of postural deformations. The quantification of the PG of 14 control subjects and 20 scoliotic patients (TLG) was realised using a stereovideographic approach. For each patient, PA and lateral X-rays were done using a digital X-ray apparatus. The TLG group shows common pathological characteristics but is forming a relatively heterogeneous group. When this class is divided in two subgroups, 9 postural parameters appeared to be different from the control group, each subgroup showing specific postural characteristics. The 3D quantification of pertinent radiological parameters and the PG evaluation should allow the classification of idiopathic scoliosis patients. Furthermore, these groups of patients could be characterised, in order to improve the diagnosis, the prognosis and the treatment, with a brace or surgically.

Relationship between gibbosity and Cobb angle during treatment of idiopathic scoliosis with the SpineCor brace.

The objective of this study was to quantify the relationship between gibbosity and spinal deformation expressed by the angle of Cobb before and during treatment with a brace for different classes of idiopathic scoliosis patients. As part of the standard treatment with the Dynamic Corrective Brace (SpineCor), 89 idiopathic scoliosis patients underwent an initial radiological examination and gibbosity measurement with a scoliometer wearing and not wearing the brace. The 89 patients were classified in relation to the apex of the scoliosis curves: thoracic (n = 29); thoracolumbar (n = 40); lumbar (n = 7) and double (n = 13). With the dynamic corrective brace, the patients showed a mean decrease of 8.3 degrees for the major Cobb angle, and a mean decrease of 2.3 degrees for their gibbosity. There was a significant positive relationship between gibbosity and Cobb angle with and without the brace for the thoracic and thoracolumbar curves. A linear regression analysis identified a small mean estimation error for the thoracic curves (7.4 degrees no-brace; 2.7 degrees with brace) and thoracolumbar curves (5.2 degrees no-brace; 5.3 degrees with brace), indicating a predictive potential of the scoliometer. The measure of gibbosity with the scoliometer provides a fairly reliable estimation of Cobb angle at the initial clinical examination of a scoliosis patient. However, when initial Cobb angle and gibbosity are considered, the measure of gibbosity when wearing a brace provides the clinician with a highly reliable estimation of the Cobb angle while in a brace. This relationship also exists for the follow-up with a brace, permitting a judgement of the patient's evolution under the treatment with SpineCor.