Kinematics of the Lumbo–Pelvic Complex under Different Loading Conditions

Abstract

The lumbo-pelvic complex is a highly complex structural system. The current investigation aims to identify the kinematics between interacting bone segments under different loading conditions. A specimen of the lumbo-pelvic complex was obtained from a human body donor and tested in a self-developed test rig. The experimental setup was designed to imitate extension, flexion, right and left lateral bending and axial rotation to the left and to the right, respectively. The vertebra L3 was firmly embedded and load was introduced via hip joints. Using a digital image correlation (DIC) system, the 3D motions of 15 markers at different landmarks were measured for each loadcase under cyclic loading. For each loadcase, the kinematics were analyzed in terms of three-dimensional relative movements between L3 and the sacrum. The usefulness of the experimental technique was demonstrated. It may serve for further biomechanical investigations of relative motion of sacroiliac and vertebral joints and deformation of bony structures.

Restricted cement augmentation in unstable geriatric midthoracic fractures treated by long-segmental posterior stabilization leads to a comparable construct stability

“…The rotation of the swivel arm was measured with an angle sensor (Incremental encoder 5821, Fritz Kübler GmbH, Germany). Furthermore, the positions of the markers were recorded with a digital image correlation system with a three-camera setup (Q400, LIMESS Messtechnik und Software GmbH, Krefeld, Germany) 9 . These measurements were taken at the beginning (10 cycles), every 500 cycles and at the end (24,990 cycles) for continuous monitoring.…”

“…As the markers are anchored into vertebral bodies, it is assumed that they represent the movement of the vertebral bodies during loading 9 . The marker positions measured with the digital image correlation system were correlated and exported into a coordinate system corresponding to a person standing upright.…”

Approach to standardized material characterization of the human lumbopelvic system—Specification, preparation and storage

“…In addition, if the development of a numerical model based on the preparation is envisaged, a prior non-destructive investigation of the entire preparation is recommended. The combination of the geometry, the obtained material data, as well as a deformation analysis, such as Range of Motion [ 14 ], enables to train, calibrate, or validate the model. However, since it is difficult to carry out such complex investigations, the structuring and logistics represent a crucial hurdle to reproducibility.…”