title: [Dislocation of double-threaded screws after stabilization of the odontoid process with the Knöringer technique].
abstract: A type III fracture of the odontoid process according to Anderson-D'Alonzo in a 92-year-old patient was stabilized anteriorly with two double-threaded screws using the technique of Knöringer. Postoperatively, cranial dislocation of the screws was evident and attempts to correct the screw position failed resulting in screw proximity to the brain stem. In a second revision the screws could be removed by an anterior approach and fusion was achieved by a posterior approach. Type III fractures of the odontoid process are usually stable and should be treated conservatively. In case of instability posterior stabilization techniques should be selected. Anterior osteosynthesis of the odontoid process with double-threaded screws in osteoporotic bone carries the risk of screw dislocation.
authors.affiliation: Zentrum für Wirbelsäulenchirurgie und Neurotraumatologie, Berufsgenosssenschaftliche Unfallklinik Frankfurt a.M., Friedberger Landstraße 430, 60389, Frankfurt am Main, Deutschland, dielres@me.com.
authors.forename: P
authors.initials: P
authors.lastname: Diel
authors.forename: K J
authors.initials: KJ
authors.lastname: Schnake
authors.forename: A
authors.initials: A
authors.lastname: Langheinrich
authors.forename: F
authors.initials: F
authors.lastname: Kandziora
mesh_terms: D000369:Aged, 80 and over; D001863:Bone Screws / Q000009:adverse effects*; D020878:Device Removal / Q000379:methods; D005260:Female; D005547:Foreign Bodies / Q000209:etiology* / Q000601:surgery*; D006801:Humans; D009809:Odontoid Process / Q000293:injuries* / Q000601:surgery*; D011475:Prosthesis Failure; D016103:Spinal Fractures / Q000150:complications / Q000601:surgery*; D016896:Treatment Outcome