A proposal of lumbosacral load wearable sensor and lumbosacral alignment estimation based on X-ray image

Abstract

Anteflexion of the spine is essential for many physical activities of daily living. However, this motion places the lumbar disks because it generats heavy load due to changes in the shape of the lumbar spine and can lead to low back pain. In older to reduce low back pain, here we proposed a wearable sensor system configuration that can estimate lumbosacral alignment and lumbar load by measuring the shape of the lumbar skin when the lumbosacral alignment changes. The shape of the lumbar skin and posture angle are measured by using curvature sensors and accelerometers. In addition, the system must be constructed in consideration of the physique, in order to absorb in a variety of human. We proposed this system by measuring the body parameters of anteflexion and studied the change in dimensions of the lumbar spine from changes in posture. By extracting the dimensions of the lumbosacral spine in X-ray images, the attitude angle, body surface area and the dimensions of the lumbosacral spine have relevance. The lumbosacral dimensions calibration method was developed by using that relation. Lumbosacral alignment estimation considering the difference in physiques is developed, and lumbosacral spine alignment was to improve the estimation accuracy. The proposed method could improve accuracy lumbosacral alignment estimation.

Relationship between Upper Body Posture Angle and Vertebral Body Posture Angle in Lateral Flexion and Rotation Posture

“…Although a small layer of fat is present between the spinous processes of the spinal column and the dorsal epidermis, changes in the spinous processes can still be observed from the epidermis. We also previously found a relationship between the epidermis and vertebral bodies from X-ray images during muscular pretensioning [13,19]. Thus, we estimated the lumbar spine alignment assuming that the shape of the epidermis (skin line) is equivalent to the smoothed curve connecting the vertebral centroids of the lumbar spine (spine line).…”

“…The system comprising 4 sets of curvature sensors and 2 inertial measurement units was developed based on X-ray image analysis. Details of the wearable sensor system have been presented elsewhere [19,20]. The spine line is a curve connecting point b 0 to point b 6 .…”