gms | German Medical Science

63rd Annual Meeting of the German Society of Neurosurgery (DGNC)
Joint Meeting with the Japanese Neurosurgical Society (JNS)

German Society of Neurosurgery (DGNC)

13 - 16 June 2012, Leipzig

Does C-TDR have a lower risk of device subsidence compared to ACDF? Two-year-results of a prospective multi-center study

Meeting Abstract

  • H.J. Meisel - Klinik für Neurochirurgie, BG Kliniken Bergmannstrost, Halle
  • P. Suchomel - Department of Neurosurgery, Liberec Hospital
  • J. Stulik - Spine Surgery Department, Teaching Hospital Prague Motol
  • J. Antinheimo - Department of Neurosurgery, Helsinki University Central Hospital
  • J. Pohjola - Department of Neurosurgery, Helsinki University Central Hospital
  • S. Sola - Klinik für Chirurgie, Universitätsklinikum Rostock
  • S. Kroppenstedt - Klinik für Neurochirurgie, Charité, Campus Virchow-Klinikum
  • C. Woiciechowsky - Neurochirurg, Berlin
  • B. Bruchmann - Wirbelsäulenchirurgie, Katholisches Klinikum Koblenz
  • M. O’Malley - Spinal surgery, Spire Cheshire Hospital
  • I. Shackleford - Spinal surgery, Spire Cheshire Hospital
  • R. Arregui - Neurosurgery, Hospital Maz, Zaragoza
  • F. Caroli - Neurochirurgia, Istituti Fisioterapici Ospitalieri, Roma, Italy
  • N. Borm - frictionless GmbH, Kiel

Deutsche Gesellschaft für Neurochirurgie. Japanische Gesellschaft für Neurochirurgie. 63. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), Joint Meeting mit der Japanischen Gesellschaft für Neurochirurgie (JNS). Leipzig, 13.-16.06.2012. Düsseldorf: German Medical Science GMS Publishing House; 2012. DocDO.13.04

doi: 10.3205/12dgnc117, urn:nbn:de:0183-12dgnc1176

Published: June 4, 2012

© 2012 Meisel 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.



Objective: Although ACDF is an effective procedure for the treatment of DDD, loss of segmental disc height and cage subsidence, possibly resulting in kyphotic deformity, pseudarthrosis and worsening of clinical outcome, are common concerns. Various factors may influence subsidence, but certainly the biomechanical situation at the bone-implant interface is an important one, influenced by the devices' operative technique, primary stability, geometry and contact area. While the preservation of segmental motion and a lower risk for adjacent segment degeneration are the main pros for C-TDR, this technology may also contribute to a reduced risk of subsidence.

Methods: Therefore we investigated the two year interim results (n = 99) of a prospective, multicenter study, performed at 11 European sites. All patients (mean age 42,6 years; male = 41, female = 58) underwent single-level total disc replacement (activ™ C disc prosthesis) between C3/4 and C6/7 (C3/4 = 2, C4/5 = 5, C5/6 = 49, C6/7 = 43) and were followed-up 6 wk, 6 mo, 1 y and 2 y postoperatively. Radiographic measures were performed independently by using computer-aided image processing. Disc height is calculated as the average anterior and posterior disc height (distance between anterior (posterior) edge of the inferior endplate of the superior vertebra, and the corresponding edge of the inferior vertebra).

Results: Mean disc heights were as follows: preop 3,7 mm, postop 6,5 mm, 6 wk 5,8 mm, 6 mo 5,7 mm, 1 y 5,7 mm, 2 y 5,6. Statistically significant differences were detected between preop/postop, postop/6 wk, 6 wk/6 mo and 1 y/2 y (p < 0,001 Linear Contrasts, ANOVA). Mean loss of disc height by level was 1,4 mm for C3/4 and C4/5, 0,8 mm for C5/6 and 0,9 mm for C6/7 (overall loss of disc height 0,9 mm). The subsidence rate (loss of height > 3 mm) in our study is 0% (0/99) or, based on a subsidence definition of > 2 mm, 6,1% (6/99).

Conclusions: Compared to literature, where cage subsidence rates of 9%– 55,6% (> 3 mm) or 45% (> 2 mm) are described, our results show a lower risk for subsidence, which is probably contributed to different design concepts of disc arthroplasties and cages in general and the anatomically adopted shape and geometry of the study device in particular.