gms | German Medical Science

56. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e. V. (DGNC)
3èmes journées françaises de Neurochirurgie (SFNC)

Deutsche Gesellschaft für Neurochirurgie e. V.
Société Française de Neurochirurgie

07. bis 11.05.2005, Strasbourg

Objective evaluation of lumbar spondylolisthesis in functional x-rays using RGB-Transformation

Objektive Evaluation der lumbalen Spondylolisthese in Funktionsaufnahmen mit der RGB-Transformation

Meeting Abstract

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  • corresponding author A. Dötterl - Neurochirurgische Klinik und Poliklinik, Klinikum rechts der Isar der Technischen Universität München
  • A. E. Trappe - Neurochirurgische Klinik und Poliklinik, Klinikum rechts der Isar der Technischen Universität München

Deutsche Gesellschaft für Neurochirurgie. Société Française de Neurochirurgie. 56. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e.V. (DGNC), 3èmes journées françaises de Neurochirurgie (SFNC). Strasbourg, 07.-11.05.2005. Düsseldorf, Köln: German Medical Science; 2005. DocP006

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Veröffentlicht: 4. Mai 2005

© 2005 Dötterl et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen ( Er darf vervielfältigt, verbreitet und öffentlich zugänglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.




The technique of choice for evaluating the amount of lumbar instability is the comparison of two sequentially performed x-ray-pictures in either kyphosis or lordosis. The measurement of the total mobility is performed by measuring the difference between the dorsal laminae of two adjacent vertebrae. Another method is to overlay two films in front of the light box aligning the vertebra beneath the spondylolisthesis with a subsequent measurement of the movement of the upper vertebrae.


We present a sophisticated method to objectively present the amount of dislocation between two vertebrae. The digital x-ray films with kyphosis and lordosis are attached to the three colour channels of a commercially available photo design software where the kyphosis is assigned to the red channel,for example, the lordosis to the green and blue channels, respectively. One of the two pictures is now electronically shifted and turned until both vertebrae beneath the spondylolysthesis are aligned. After that the channels are combined and result in a single colour- coded picture. This procedure is described as RGB-Transformation (corresponding to the red-green-blue channels).


In this picture the kyphotic spine is presented in red, the lordotic spine is presented in cyan. Using this colour coding procedure, each vertebra is easily seen to belong to the kyphosis or to the lordosis picture even if the movement is only slight. The amount of movement can now easily be measured by the distance of the corresponding dorsal laminae. Thus the evaluation of the mobility is reduced to a single measurement in only one picture which contains information of both x-ray films.


The amount of lumbar spondylolisthesis is objectively displayed resulting in an easier evaluation process. Moreover, as the picture can be stored, the need for a new evaluation at another time or by another neurosurgeon is eliminated.