title: Revision surgery for cervical artificial disc: Surgical technique and clinical results.
abstract: OBJECTIVE
  Cervical artificial disc replacement (C-ADR) was developed with the goal of preserving mobility of the cervical segment in patients with degenerative disc disease. So far, little is known about experiences with revision surgery and explantation of C-ADRs. Here, we report our experience with revision the third generation, Galileo-type disc prosthesis from a retrospective study of two institutions.
  
  
  METHODS
  Between November 2008 and July 2016, 16 patients with prior implantation of C-ADR underwent removal of the Galileo-type disc prosthesis (Signus, Medizintechnik, Germany) due to a call back by industry. In 10 patients C-ADR was replaced with an alternative prosthesis, 6 patients received an ACDF. Duration of surgery, time to revision, surgical procedure, complication rate, neurological status, histological findings and outcome were examined in two institutions.
  
  
  RESULTS
  The C-ADR was successfully revised in all patients. Surgery was performed through the same anterior approach as the initial access. Duration of the procedure varied between 43 and 80min. Access-related complications included irritation of the recurrent nerve in one patient and mal-positioning of the C-ADR in another patient. Follow up revealed two patients with permanent mild/moderate neurologic deficits, NDI (neck disability index) ranged between 10 and 42%.
  
  
  CONCLUSIONS
  Anterior exposure of the cervical spine for explantation and revision of C-ADR performed through the initial approach has an overall complication rate of 18.75%. Replacements of the Galileo-type disc prosthesis with an alternative prosthesis or conversion to ACDF are both suitable surgical options without significant difference in outcome.
authors.affiliation: Department of Neurosurgery, Charité, Berlin, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Onken
authors.affiliation: Department of Neurosurgery, TMU, Munich, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Reinke
authors.affiliation: Department of Neuropathology, Charité, Berlin, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Radke
authors.affiliation: Department of Neurosurgery, Charité, Berlin, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Finger
authors.affiliation: Department of Neurosurgery, Charité, Berlin, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Bayerl
authors.affiliation: Department of Neurosurgery, Charité, Berlin, Germany. Electronic address: peter.vajkoczy@charite.de.
authors.forename: P
authors.initials: P
authors.lastname: Vajkoczy
authors.affiliation: Department of Neurosurgery, TMU, Munich, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Meyer
mesh_terms: D000328:Adult; D002574:Cervical Vertebrae / Q000601:surgery*; D005260:Female; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D019736:Prostheses and Implants / Q000009:adverse effects*; D012086:Reoperation / Q000379:methods*; D012189:Retrospective Studies; D059145:Total Disc Replacement / Q000009:adverse effects / Q000379:methods*
keywords: Cervical artificial disc replacement; Complication rate; Operative technique; Outcome; Retrospective study; Revision surgery