The use of a photogrammetric method for the three-dimensional evaluation of spinal correction in scoliosis.

Purpose: Clinical parameters, characterizing the spinal deformations due to scoliosis, are still directly measured on the spinal curve plane projections.

Methods: A 3D spinal curve has been reconstructed from its two projections, using photogrammetric techniques. Each spinal curve is a compound of several plane regions, where it is purely flexed, and short zones of connection, where abduction and axial rotation components are concentrated.

Accessing 3D Location of Standing Pelvis: Relative Position of Sacral Plateau and Acetabular Cavities versus Pelvis.

The goal of this paper is to access to pelvis position and morphology in standing posture and to determine the relative locations of their articular surfaces. This is obtained from coupling biplanar radiography and bone modeling. The technique involves different successive steps.

Geometric Structure of 3D Spinal Curves: Plane Regions and Connecting Zones.

This paper presents a new study of the geometric structure of 3D spinal curves. The spine is considered as an heterogeneous beam, compound of vertebrae and intervertebral discs. The spine is modeled as a deformable wire along which vertebrae are beads rotating about the wire.

Spino-pelvic postural changes between the standing and sitting human position: proposal of a method for its systematic analysis.

This study presents numerical tools, based on biplanar radiography, allowing to analyze the 3D changes in position and length of the various spinal segments with respect to the pelvis which occur between the standing and sitting positions. Three asymptomatic adult subjects and twelve adult patients with low back pain or scoliosis had biplanar calibrated radiographs in the erect posture and sitting position. The 3D points of the spinal curve were then reconstructed from their plane projections using a standard photogrammetric technique.

Classification of pelvic and spinal postural patterns in upright position. Specific cases of scoliotic patients.

The 3D analyses of spinal shapes and postural features give a great number of data. The global patient posture includes his pelvic morphology and tilting, and his pelvic and spinal balance. In some scoliotic spines, the spinal curve belongs to a unique plane.