title: Prospective study on serum metal levels in patients with metal-on-metal lumbar disc arthroplasty.
abstract: OBJECTIVE
  Metal-on-metal total disc replacement is a recent alternative treatment for degenerative disc disease. Wear and corrosion of these implants can lead to local and systemic transport of metal debris. This prospective longitudinal study examined the serum chromium and cobalt levels in 24 patients with cobalt-chromium alloy metal-on-metal lumbar disc replacements.
  
  
  METHODS
  Serum was assayed for chromium (Cr) and cobalt (Co) using high-resolution inductively-coupled plasma-mass spectrometry. Detection limits were 0.015 ng/mL for Cr and 0.04 ng/mL for Co.
  
  
  RESULTS
  Median serum Co levels at pre-op, 3, 6, 12, 24, and 36-months post-op were 0.10, 1.03, 0.96, 0.98, 0.67, and 0.52 ng/mL, respectively. Median serum Cr levels were 0.06, 0.49, 0.65, 0.43, 0.52, and 0.50 ng/mL, respectively.
  
  
  CONCLUSIONS
  In general, these results indicated that serum Co and Cr levels are elevated at all postoperative time points and are of the same order of magnitude as those observed in well-functioning metal-on-metal surface replacements of the hip and in metal-on-metal total hip replacements at similar postoperative time points.
authors.affiliation: Spine Research Center, The Orthopedic Center of St. Louis, 14825 North Outer Forty Road, Suite 320, St. Louis, MO 63017, USA. mfgspine@gmail.com
authors.forename: Matthew F
authors.initials: MF
authors.lastname: Gornet
authors.forename: J K
authors.initials: JK
authors.lastname: Burkus
authors.forename: M L
authors.initials: ML
authors.lastname: Harper
authors.forename: F W
authors.initials: FW
authors.lastname: Chan
authors.forename: A K
authors.initials: AK
authors.lastname: Skipor
authors.forename: J J
authors.initials: JJ
authors.lastname: Jacobs
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D002857:Chromium / Q000097:blood*; D002858:Chromium Alloys; D003035:Cobalt / Q000097:blood*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000601:surgery*; D008137:Longitudinal Studies; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D011446:Prospective Studies; D011474:Prosthesis Design; D013997:Time Factors; D059145:Total Disc Replacement / Q000295:instrumentation* / Q000379:methods
chemical_list: D015415:Biomarkers; D002858:Chromium Alloys; D002857:Chromium; D003035:Cobalt