gms | German Medical Science

54. Jahrestagung der Norddeutschen Orthopädenvereinigung e. V.

Norddeutsche Orthopädenvereinigung

16.06. bis 18.06.2005, Hamburg

Total nucleus replacement (TNR), with an injectable, in-situ curable arthroplasty system : one year clinical experience

Meeting Abstract

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  • corresponding author M. Ahrens - Klinikum Neustadt, Klinik für Wirbelsäulenchirurgie mit Skoliosezentrum, Neustadt
  • J. Sherman - Edina
  • H. Yuan - Syracuse
  • H. Halm - Neustadt

Norddeutsche Orthopädenvereinigung. 54. Jahrestagung der Norddeutschen Orthopädenvereinigung e.V.. Hamburg, 16.-18.06.2005. Düsseldorf, Köln: German Medical Science; 2005. Doc05novW1.04

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

Published: June 13, 2005

© 2005 Ahrens 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.




An injectable, in-situ curable arthroplasty system for total nucleus replacement (TNR), is currently being studied for the treatment of degenerative disc disease (DDD). The system is consisting of a two-part polyurethane, which serves as a disc nucleus replacement. The polyurethane is injected under pressure into a containment balloon after complete evacuation of the disc nucleus.

Material and methods

VAS pain scores, Oswestry scores, and radiographic assessments are collected preoperatively and at multiple follow-up intervals: 6 weeks, 3 months, 6 months, 1 and 2 years. Disc height of the affected level disc is measured pre-operatively and at each follow-up interval.


A total of 11 patients have been enrolled at this site to date. We experienced two complications with one conversion to a fusion and one improper injection process. Data for the one year follow up (6 patients), males (71 %) with a mean age of 39.1, are presented. The disc levels include L4-5 (29%) and L5-S1 (71%). Mean duration of surgery was 78,1 minutes. Mean pre-operative back pain VAS score was 6,9 and improved to 3,7 at 12 months. Mean preoperative Oswestry score was 46,2 and improved to 23,5 at 12 months.


The clinical results are encouraging and early technical challenges could be solved. The used technique is able to control volume, size and location of the nucleus prior to the final volume and pressure controlled polymer injection. The technique is minimal invasive and safe, but requires an adequate complete nucleus removal as a prerequisite.