title: Hinge Fracture during Cervical Open-door Laminoplasty: Does it Affect Clinical and Radiographic Outcomes?
abstract: OBJECTIVE
  The purpose of this study was to determine whether the status of the hinge gutter affected clinical and radiographic outcomes of cervical open door laminoplasty.
  
  
  METHODS
  We retrospectively analyzed 43 patients who had undergone cervical open door laminoplasty. 23 CT scans were performed at 2 days post-operation. The number of CT scans at 3, 6, 12 and 24 months were 16, 12, 21 and 11, respectively. We collected perioperative and follow-up data, including clinical and radiographic results.
  
  
  RESULTS
  There were 7 patients without a hinge fracture and 16 patients with one or more hinge fractures at 2 days postoperation. There were 90 hinges, and the rate of ideal greenstick deformation of the hinge was 63% on 2-day-postoperative CT scans. Postoperative VAS scores of neck pain (p=0.012) in patients without a hinge fracture were higher than in patients with hinge fractures. The hinge healing rates were 37% at 3 months, 57.4% at 6 months, 86.4% at 12 months, and 85.4% at 24 months. Among the patients, 14 patients had healed hinges, and 7 patients had one or more hinge(s) that was/were not healed at 12 months post-operation. However, in clinical and radiographic outcomes, there was no difference between these patients.
  
  
  CONCLUSIONS
  Cervical open door laminoplasty was safe and provided stable reconstruction of laminar expansion. In radiographs, the difference between hinges that had healed and hinges that had not healed was statistically negligible. Hinge fractures might not influence the clinical and radiographic outcomes of cervical open door laminoplasty.
authors.affiliation: Catholic Neuroscience Center, Department of Neurosurgery, Yeouido St. Mary's Hospital, The Catholic University College of Medicine, Seoul, Korea.
authors.forename: Sung Hoon
authors.initials: SH
authors.lastname: Cho
authors.affiliation: Catholic Neuroscience Center, Department of Neurosurgery, Yeouido St. Mary's Hospital, The Catholic University College of Medicine, Seoul, Korea.
authors.forename: Jung Hwan
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Catholic Neuroscience Center, Department of Neurosurgery, Yeouido St. Mary's Hospital, The Catholic University College of Medicine, Seoul, Korea.
authors.forename: Chung Kee
authors.initials: CK
authors.lastname: Chough
authors.affiliation: Catholic Neuroscience Center, Department of Neurosurgery, Yeouido St. Mary's Hospital, The Catholic University College of Medicine, Seoul, Korea.
authors.forename: Won Il
authors.initials: WI
authors.lastname: Joo
authors.affiliation: Catholic Neuroscience Center, Department of Neurosurgery, Yeouido St. Mary's Hospital, The Catholic University College of Medicine, Seoul, Korea.
authors.forename: Hae Kwan
authors.initials: HK
authors.lastname: Park
authors.affiliation: Catholic Neuroscience Center, Department of Neurosurgery, Yeouido St. Mary's Hospital, The Catholic University College of Medicine, Seoul, Korea.
authors.forename: Kyung Jin
authors.initials: KJ
authors.lastname: Lee
authors.affiliation: Catholic Neuroscience Center, Department of Neurosurgery, Yeouido St. Mary's Hospital, The Catholic University College of Medicine, Seoul, Korea.
authors.forename: Hyoung Kyun
authors.initials: HK
authors.lastname: Rha
keywords: Cervical vertebrae; Fracture; Laminoplasty; Treatment outcome
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