title: Bony fusion through an empty cervical disc interspace implant.
abstract: OBJECTIVE
  Today most cervical intervertebral implants (cages) have at least one cranio-caudal hole which can be filled to facilitate bony fusion. Whether this should be done or not remains a matter of debate. The assessment of bony fusion remains difficult, especially in titanium implants. Evaluation is therefore reserved for problem cases and revisions.
  
  
  METHODS
  We report one case with recurrent problems years after anterior cervical discectomy followed by the implantation of a titanium cage without an additional bone grafting procedure. The patient was revised and the contents of the cage examined histologically.
  
  
  RESULTS
  The case was considered fused on plain radiograph investigation. Histological examination showed solid bone formation through the hollow interspace.
  
  
  CONCLUSIONS
  Solid bone formation through an empty implant is possible. In the discussion about bone substitutes or bone graft alternatives this fact should be taken into account.
authors.affiliation: Department of Neurosurgery, University Clinics Münster, Münster, Germany. j.schroder@web.de
authors.forename: J
authors.initials: J
authors.lastname: Schröder
authors.forename: C
authors.initials: C
authors.lastname: Schul
authors.forename: M
authors.initials: M
authors.lastname: Hasselblatt
authors.forename: H
authors.initials: H
authors.lastname: Wassmann
mesh_terms: D000368:Aged; D001846:Bone Development / Q000502:physiology; D016025:Bone Transplantation; D001842:Bone and Bones / Q000473:pathology*; D002574:Cervical Vertebrae / Q000601:surgery*; D017586:Diskectomy; D006801:Humans; D007403:Intervertebral Disc / Q000601:surgery*; D008297:Male; D019736:Prostheses and Implants / Q000009:adverse effects*; D012008:Recurrence; D013123:Spinal Fusion / Q000009:adverse effects*; D014025:Titanium
chemical_list: D014025:Titanium