Laser Based Spatial Spine Curve Determination in Scoliosis

We present the development of a novel method for the automatic determination of a spatial spine curve based on the measured 3D shape of the human back (automatic curve) with the 3D laser profilometer. The measuring system is based on a line laser triangulation, its measuring range at the distance of 1 m is 300×700×500 mm, the measurement takes about 10 seconds and the single point measurement accuracy is 0.1 mm. The method allows us to compare an automatically determined spatial spine curve with a spatial curve, determined by the physician (reference curve) with the method of root mean square deviation (RMSD) in the frontal and sagittal plane. To validate the method both automatic and reference curve were compared on one subject in three different upright postures with arms in positions: 1. arms released beside the body, 2. upper arm in the horizontal position and forearm in vertical position upwards, 3. arms vertically at full stretch upwards. The results showed that the repeatability of the presented method for all three postures in the frontal and sagittal planes was 0.9 mm and 0.2 mm, respectively, thus allowing to assess a valid quantitative analysis of spine curve course on the surface of the human back regardless of the human upright posture.