gms | German Medical Science

54. Jahrestagung der Norddeutschen Orthopädenvereinigung e. V.

Norddeutsche Orthopädenvereinigung

16.06. bis 18.06.2005, Hamburg

Posterior-impingement after lumbar total disc replacement: a relevant problem?

Meeting Abstract

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  • corresponding author B. Cakir - Orthop.Abteilung mit Querschnittgelähmtenzentrum, der Universität Ulm, Ulm
  • W. Puhl - Ulm
  • R. Schmidt - Ulm

Norddeutsche Orthopädenvereinigung. 54. Jahrestagung der Norddeutschen Orthopädenvereinigung e.V.. Hamburg, 16.-18.06.2005. Düsseldorf, Köln: German Medical Science; 2005. Doc05novEP116

The electronic version of this article is the complete one and can be found online at:

Published: June 13, 2005

© 2005 Cakir et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.




One of the main postulated basic principles of total disc replacement (TDR) is the preservation of flexion/extension ability. In neutral position the ideal disc prosthesis should not stay in maximal possible extension which would imply an impingement of the prosthesis. An impingement can cause shear strains on the prosthesis endplates which probably accelerate loosening. The purpose of study was to evaluate a possible impingement after TDR.


In 29 patients with a mean age of 42.4 ± 6.5 years the segmental lordosis and flexion/extension ability was measured after single-level disc replacement with the Prodisc II® . The follow up interval averaged 13.2 months.


Pre- and postoperative lateral X-rays in neutral position, in maximum flexion and extension were assesed. The angulation of prosthesis in neutral position and the extension ability on dynamic x-rays were measured with the Cobb-Method.


15 patients showed no extension ability on dynamic x-rays and 10 of these 15 patients had an impingement with maximum extension of the prosthesis on x-rays in neutral position. In the remaining 14 patients the extension ability averaged pre-/postoperatively 2.3°/1.3° (p=0.115). In 4 of the 14 patients the prosthesis showed an impingement in maximum extension and in 10 patients the prosthesis was not in maximum possible extension.


An impingement was recognized in nearly 30% of the cases after implantation of the ProDisc. It still remains unclear if an impingement will result in facet joint protection or will trigger a loosening of the implant.