title: Delayed Migration of Fractured K-wire Causing Vertebral Artery Invagination After Anterior Atlantoaxial Fixation: A Case Report.
abstract: BACKGROUND
  Most of the physician's attention during spinal surgery, when using wires and screws, is toward the avoidance of injuries of critical structures (nerves and vessels). When such wires are broken during surgery, the most important point is to take them out safely or, if it is impossible, to leaf them in secure place and follow the patient closely. Migrations of broken Kirschner wire (K-wire) are well known in literature; however, to the best of our knowledge, migration of a fractured K-wire during anterior atlantoaxial fixation of cervical spine has not been reported in the literature.
  
  
  METHODS
  We report a case in which a fractured K-wire was imbedded in the lateral mass of C1 for 3 years and then migrated to endanger the dominant right vertebral artery. By using posterior approach and drilling right part of posterior arch of C1, we manage to secure the vertebral artery. The broken K-wire was extracted successfully. In our case, with optimal follow-up, the burred wire inside hard bone was moved in delayed fashion to come out of the bone, grooving the dominant vertebral artery.
  
  
  CONCLUSIONS
  Our recommendation is to inspect the K-wire before using it and to try retrieve as much as possible when removing it.
authors.affiliation: Department of Neurosurgery, Helsinki University Central Hospital, Helsinki, Finland. Electronic address: ext-ahmad.hafez@hus.fi.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Hafez
authors.affiliation: Department of Neurosurgery, Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: Tarik F
authors.initials: TF
authors.lastname: Ibrahim
authors.affiliation: Department of Neurosurgery, Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: Rahul
authors.initials: R
authors.lastname: Raj
authors.affiliation: Department of Neurosurgery, Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: Jussi
authors.initials: J
authors.lastname: Antinheimo
authors.affiliation: Department of Neurosurgery, Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: Jari
authors.initials: J
authors.lastname: Siironen
authors.affiliation: Department of Neurosurgery, Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: Juha
authors.initials: J
authors.lastname: Hernesniemi
mesh_terms: D000293:Adolescent; D001268:Atlanto-Axial Joint / Q000601:surgery; D001864:Bone Wires / Q000009:adverse effects*; D020878:Device Removal / Q000379:methods; D005548:Foreign-Body Migration / Q000209:etiology* / Q000601:surgery*; D005593:Fracture Fixation, Internal / Q000009:adverse effects* / Q000295:instrumentation; D006801:Humans; D008297:Male; D016896:Treatment Outcome; D014656:Vascular Surgical Procedures / Q000379:methods; D014715:Vertebrobasilar Insufficiency / Q000209:etiology* / Q000601:surgery*
keywords: Atlantoaxial fixation; K-wire migration; Vertebral artery