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Dynamic SST for monitoring position and changes in kyphosis/lordosis angles


Spine & Surface Topography (SST) has been used to perform spine diagnostics for more than 20 years. Until recently, static scans were primarily used, as dynamic scans were not properly scientifically and clinically evaluated. Also, the hardware required to perform the dynamic scan was expensive and too slow for a proper clinical use. Due to the emergence of new technology, it is now possible to record and analyze surfaces with a frequency of up to 50 Hertz. The formetric 4D (DIERS International GmbH, Schlangenbad, Germany) static and dynamic SST system records and reconstructs the spinal position of a normally standing patient, with an additional measurement, performs the same tasks while the patient isduring walking in at a sequence of 50 fps.[1] The reconstruction of the spine is done according to follows the methods of Hierholzer / Drerup.[2]


To use static and dynamic surface topography in monitoring changes in kyphosis and lordosis angles during the normal walking stride of a patient (treadmill, 5-10 sec, 50 fps) in comparison to a patient in a normal standing position.


Using the formetric 4D, 100 static and dynamic measurements of both pathologic and healthy patients were taken. For this study, the output parameters for the angles ICT-ITL (kyphosis) and ITL-ILS (lordosis) were analyzed.[3] For dynamic measurements the median values for kyphosis and lordosis were used and compared with the values from static measurements using linear regressions.


The results of linear regressions between the static and dynamic measurements of kyphosis and lordosis angles show a high significance. This validates the usability of dynamic SST compared to static SST. A second result shows that in most of the observed patients the median of kyphosis and lordosis angles from dynamic SST is smaller than in a static SST.

Conclusions and discussion

Dynamic SST can be used for further studies of kyphosis and lordosis angles. Dynamic SST gives additional information for lordosis and kyphosis angles that cannot be seen in static SST nor in other static measurement technologies.


  1. Betsch M, Wild M, Jungbluth P, Hakimi M, Windolf J, Haex B, Horstmann T, Rapp W: Reliability and validity of 4D rasterstereography under dynamic conditions. Comput Biol Med. 2011, 41 (6): 308-312. 10.1016/j.compbiomed.2011.03.008. []

    Article  PubMed  Google Scholar 

  2. Drerup B, Hierholzer E, Ellger B: Shape analysis of the lateral and frontal projection of spine curves assessed from rasterstereographs. The international research society of spinal deformities. 1st meeting. June 16-19, Stockholm. 1996

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  3. Mohokum M, Mendoza S, Udo W, Sitter H, Paletta JR, Skwara A: Reproducibility of rasterstereography for kyphotic and lordotic angles, trunk length, and trunk inclination: a reliability study. Spine(Phila Pa 1976). 2010, 35 (14): 1353-1358. []

    Google Scholar 

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Correspondence to Helmut Diers.

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This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Diers, H., Diers, C., Firle, E. et al. Dynamic SST for monitoring position and changes in kyphosis/lordosis angles. Scoliosis 8 (Suppl 2), O32 (2013).

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