title: Cervical expansive laminoplasty with 90° box-shape double door method.
abstract: OBJECTIVE
  The aim of this study is to introduce the surgical method with miniplate and compared the expansion rate of the spinal canal area with other kinds of lamina spacers.
  
  
  METHODS
  Between June. 2008 and May 2011, we performed expansive cervical laminoplasty on 61 patients. We analyzed the results of these operations, examining type of lamina spacer used, spinal canal areas between pre- and postoperative CT scans, and operative methods.
  
  
  RESULTS
  39 patients were analyzed retrospectively. Miniplates were used in 21 patients with 103 levels. Hydroxyapatite (HA) was used in 6 patients with 29 levels, and Centerpiece® was used in 12 patients with 54 levels. The expansion area was calculated using Photoshop CS3®. The expansion rate of the miniplates was 76.5%, that of HA was 49.8%, and that obtained with Centerpiece was 50.6%. The excellent 90° box-shaped widening of the laminae achieved through the surgery can be checked easily by AP X-ray. All miniplates are positioned horizontally and parallel, and the lamina is seen as a pedicle of thoracic or lumbar spine due to its 90° erect position. Neurologic improvement and clinical outcomes will be discussed. No complications were reported with miniplates.
  
  
  CONCLUSIONS
  Box-shaped laminoplasty with miniplates is the widest spinal canal expansion method among the three types of implants examined.
authors.affiliation: Department of Neurosurgery, Spine and Spinal Cord Institute, Gangnam Severance Spine Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Jung Hoon
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Neurosurgery, National Health Insurance Corporation Ilsan Hospital, Yonsei University College of Medicine, Goyang, Korea.
authors.forename: Ho Yeol
authors.initials: HY
authors.lastname: Zhang
authors.affiliation: Department of Neurosurgery, National Health Insurance Corporation Ilsan Hospital, Yonsei University College of Medicine, Goyang, Korea.
authors.forename: Young Mok
authors.initials: YM
authors.lastname: Park
keywords: Double-door laminoplasty; Open-door laminoplasty; Spinal canal area