Method to geometrically personalize a detailed finite-element model of the spine.

To date, developing geometrically personalized and detailed solid finite-element models (FEMs) of the spine remains a challenge, notably due to multiple articulations and complex geometries. To answer this problem, a methodology based on a free-form deformation technique (kriging) was developed to deform a detailed reference finite-element mesh of the spine (including discs and ligaments) to the patient-specific geometry of 10- and 82-year-old asymptomatic spines. Different kriging configurations were tested: with or without smoothing, and control points on or surrounding the entire mesh.

Biomechanics of the intra-operative lateral decubitus position for the scoliotic spine: effect of the pelvic obliquity.

The intra-operative prone position used for the posterior instrumentation of scoliotic patients has been shown to reduce the spinal deformities prior to instrumentation by 37% on average. However, the effects of the lateral decubitus position used for anterior approaches and minimally invasive techniques have not been investigated. The objectives were to characterize, model and study the biomechanics of this intra-operative posture.

Accessing the influence of repositioning on the pelvis' 3-D orientation in wheelchair users.

This study aimed at evaluating the effects of mechanical repositioning, obtained by the increase in seat-to-back (STB) and system tilt angles, on the position of the pelvis with spinal-cord injured subjects seated in a wheelchair. The noninvasive method used combined magnetic resonance imaging (MRI) images of the whole pelvis obtained in a supine posture and ultrasound images of the pelvic iliac crests obtained in four seating positions. The matching of the two image data sets enabled the location of fourteen pelvic landmarks in the seated positions.