title: Risk Factors for Delayed Hinge Fracture after Plate-Augmented Cervical Open-Door Laminoplasty.
abstract: OBJECTIVE
  Delayed hinge fracture (HF) that develops after cervical open door laminoplasty can be a source of postoperative complications such as axial pain. However, risk factors related to this complication remain unclear. We performed a retrospective clinical series to determine risk factors for delayed HF following plate-only open-door cervical laminoplasty.
  
  
  METHODS
  Patients who underwent plate-only open-door laminoplasty and had available postoperative computed tomography (CT) scans (80 patients with 270 laminae) were enrolled. Hinge status, hinge gutter location, open location, hinge width, number of screws used, operation level, and open angle were observed in the CT to determine radiographic outcome. Demographic data were collected as well. Radiographic and clinical parameters were analyzed using univariate and multivariate logistic regression analysis to determine the risk factors for HF.
  
  
  RESULTS
  Univariate logistic regression analysis results indicated poor initial hinge status, medially placed hinge gutter, double screw fixation on the elevated lamina, upper surgical level, and wide open angle as predictors for HF (p<0.05). Initial hinge status seemed to be the most powerful risk factor for HF (p=0.000) and thus was collinear with other variables. Therefore, multivariate logistic regression analysis was performed excluding initial hinge status, and the results indicated that medially placed hinge gutter, double screw fixation on the elevated lamina, and upper surgical level were risk factors for HF after adjustment for other confounding factors.
  
  
  CONCLUSIONS
  To prevent HF and to draw a successful postoperative outcome after cervical laminoplasty, surgical and clinical precautions should be considered.
authors.affiliation: Department of Neurosurgery, Korea University Guro Hospital, Seoul, Korea.; Department of Neurosurgery, Korea University Anam Hospital, Seoul, Korea.
authors.forename: Junseok W
authors.initials: JW
authors.lastname: Hur
authors.affiliation: Department of Neurosurgery, Korea University Guro Hospital, Seoul, Korea.
authors.forename: Youn-Kwan
authors.initials: YK
authors.lastname: Park
authors.affiliation: Department of Neurosurgery, Korea University Guro Hospital, Seoul, Korea.; Department of Neurosurgery, Korea University Ansan Hospital, Ansan, Korea.
authors.forename: Bum-Joon
authors.initials: BJ
authors.lastname: Kim
authors.affiliation: Department of Neurosurgery, Korea University Guro Hospital, Seoul, Korea.
authors.forename: Hong-Joo
authors.initials: HJ
authors.lastname: Moon
authors.affiliation: Department of Neurosurgery, Korea University Guro Hospital, Seoul, Korea.
authors.forename: Joo-Han
authors.initials: JH
authors.lastname: Kim
keywords: Cervical; Fracture; Hinge; Lamina; Laminoplasty; Risk factors