title: Time-dependent release of cobalt and chromium ions into the serum following implantation of the metal-on-metal Maverick type artificial lumbar disc (Medtronic Sofamor Danek).
abstract: BACKGROUND
  In total hip endoprosthetics and consequently for TDA, metal-on-metal combinations are used with the aim of reducing wear debris. In metal-on-metal TDA the release of metal ions has until now been secondary to the main discussion.
  
  
  METHODS
  In order to investigate the ion release following the implantation of the metal-on-metal Maverick type artificial lumbar disc we measured the serum cobalt and chromium concentration following implantation of 15 Maverick TDAs (monosegmental L5/S1, n = 5; bisegmental L4/5 and L5/S1, n = 5; average age 36.5 years). Five healthy subjects (no metal implants) acted as a control group. The two measurements of the metals were carried out using the absorption spectrometry after an average of 14.8 and 36.7 months.
  
  
  RESULTS
  In summary, the concentrations of cobalt and chromium ions in the serum at both follow-ups amounted on average to 3.3 microg/l (SD 2.6) for cobalt and 2.2 microg/l (SD 1.5) for chromium. These figures are similar to the figures shown in the literature following the implantation of metal-on-metal THA. After a comparison to the control group, both the chromium and cobalt levels in the serum showed visible increases regarding the first and the second follow-up.
  
  
  CONCLUSIONS
  As there is still a significant release of cobalt and chromium into the serum after an average follow-up of 36.7 months a persistent release of these ions must be taken into consideration. Despite the evaluation of the systemic and local effects of the release of Cr/Co from orthopaedic implants has not yet been concluded, one should take into consideration an explanation given to patients scheduled for the implantation of a metal-on-metal TDA about these results and the benefits/risks of alternative combinations of gliding contact surfaces.
authors.affiliation: Department of Orthopedics and Traumatology, Martin-Luther-University of Halle-Wittenberg, Faculty of Medicine, Halle/Saale, Germany. alexander.zeh@medizin.uni-halle.de
authors.forename: Alexander
authors.initials: A
authors.lastname: Zeh
authors.forename: Claudia
authors.initials: C
authors.lastname: Becker
authors.forename: Michael
authors.initials: M
authors.lastname: Planert
authors.forename: Peter
authors.initials: P
authors.lastname: Lattke
authors.forename: David
authors.initials: D
authors.lastname: Wohlrab
mesh_terms: D000293:Adolescent; D000328:Adult; D002857:Chromium / Q000493:pharmacokinetics*; D002858:Chromium Alloys; D003035:Cobalt / Q000493:pharmacokinetics*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007403:Intervertebral Disc / Q000601:surgery*; D007477:Ions / Q000493:pharmacokinetics*; D017116:Low Back Pain / Q000601:surgery; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000097:blood; D019736:Prostheses and Implants; D011474:Prosthesis Design; D013054:Spectrophotometry, Atomic; D055815:Young Adult
chemical_list: D002858:Chromium Alloys; D007477:Ions; D002857:Chromium; D003035:Cobalt