title: Modified Open-door Laminoplasty Using Hydroxyapatite Spacers and Miniplates.
abstract: OBJECTIVE
  Cervical laminoplasty has been widely accepted as one of the major treatments for cervical myelopathy and various modifications and supplementary procedures have been devised to achieve both proper decompression and stability of the cervical spine. We present the retrospectively analyzed results of a modified unilateral open-door laminoplasty using hydroxyapatite (HA) spacers and malleable titanium miniplates.
  
  
  METHODS
  From June 2008 to May 2012, among patients diagnosed with cervical spondylotic myelopathy and ossification of posterior longitudinal ligament, the patients who received laminoplasty were reviewed. Clinical outcome was assessed using Frankel grade and Japanese Orthopaedic Association score. The radiologic parameters were obtained from plain films, 3-dimensional computed tomography and magnetic resonance images.
  
  
  RESULTS
  A total of 125 cervical laminae were operated in 38 patients. 11 patients received 4-level laminoplasty and 27 patients received 3-level laminoplasty. Postoperatively, the mean Frankel grade and JOA score were significantly improved from 3.97 to 4.55 and from 12.76 to 14.63, respectively (p<0.001). Radiologically, cervical curvature was worsened from 19.09 to 15.60 (p=0.025). The percentage of range of motion preservation was 73.32±22.39%. The axial dimension of the operated spinal canal was increased from 1.75 to 2.70 cm(2) (p<0.001).
  
  
  CONCLUSIONS
  In the presenting study, unilateral open-door laminoplasty using HA spacers and miniplates appears to be a safe, rapid and easy procedure to obtain an immediate and rigid stabilization of the posterior elements of the cervical spine. This modified laminoplasty method showed effective expansion of the spinal canal and favorable clinical outcomes.
authors.affiliation: Department of Neurosurgery, Ansan Hospital, Korea University College of Medicine, Ansan, Korea.
authors.forename: Sung-Won
authors.initials: SW
authors.lastname: Jin
authors.affiliation: Department of Neurosurgery, Ansan Hospital, Korea University College of Medicine, Ansan, Korea.
authors.forename: Se-Hoon
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Neurosurgery, Ansan Hospital, Korea University College of Medicine, Ansan, Korea.
authors.forename: Bum-Joon
authors.initials: BJ
authors.lastname: Kim
authors.affiliation: Department of Neurosurgery, Ansan Hospital, Korea University College of Medicine, Ansan, Korea.
authors.forename: Jong-Il
authors.initials: JI
authors.lastname: Choi
authors.affiliation: Department of Neurosurgery, Ansan Hospital, Korea University College of Medicine, Ansan, Korea.
authors.forename: Sung-Kon
authors.initials: SK
authors.lastname: Ha
authors.affiliation: Department of Neurosurgery, Ansan Hospital, Korea University College of Medicine, Ansan, Korea.
authors.forename: Sang-Dae
authors.initials: SD
authors.lastname: Kim
authors.affiliation: Department of Neurosurgery, Ansan Hospital, Korea University College of Medicine, Ansan, Korea.
authors.forename: Dong-Jun
authors.initials: DJ
authors.lastname: Lim
keywords: Bone plates; Cervical vertebrae; Hydroxyapatites; Ossification of posterior longitudinal ligament; Spinal cord compression