title: Delayed hyper-reactivity to metal ions after cervical disc arthroplasty: a case report and literature review.
abstract: METHODS
  Anecdotal case report.
  
  
  OBJECTIVE
  To report a very interesting and perplexing complication of cervical total disc arthroplasty that has not been previously reported in literature.
  
  
  BACKGROUND
  Although there has been increasing interest in the field of artificial disc replacement to treat cervical degenerative disc disease, not much has been mentioned in the literature about the potential complications of the disc itself. We encountered a delayed complication in 1 patient that has not been reported in the literature.
  
  
  METHODS
  Thirty-nine-year-old white woman received total disc arthroplasty for herniated intervertebral disc at C5-C6 level uneventfully. She had recurrence of symptoms 9 months after the procedure and failed to respond to conservative measurements. Imaging revealed soft tissue mass posterior to the implanted disc encroaching the spinal cord.
  
  
  RESULTS
  Surgical explantation and exploration of the disc space revealed thick layer of abnormal hyaline cartilaginous tissue with chronic inflammatory debris. The patient had complete resolution of symptoms after the revision surgery.
  
  
  CONCLUSIONS
  Although there is increased enthusiasm about motion preservation technology and disc replacement surgery for intervertebral disc herniation, unexpected complications like the present case need to be shared within the scientific community to better understand the risks associated with these new and promising devices.
authors.affiliation: Spine Institute of Louisiana, 1500 Line Avenue, Shreveport, LA 71101, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Cavanaugh
authors.forename: Pierce D
authors.initials: PD
authors.lastname: Nunley
authors.forename: Eubulus J
authors.initials: EJ
authors.lastname: Kerr
authors.forename: David J
authors.initials: DJ
authors.lastname: Werner
authors.forename: Ajay
authors.initials: A
authors.lastname: Jawahar