title: Bilateral open-door cervical expansive laminoplasty with hydroxyapatite spacers and titanium screws.
abstract: OBJECTIVE
  The authors report a simple method for bilateral open-door cervical expansive laminoplasty in which hydroxyapatite (HA) spacers are secured by titanium screws. A biomechanical study was also conducted to confirm the strength of the screw fixation.
  
  
  METHODS
  A unilateral posterior approach was used to allow preservation of the posterior supporting elements (the posterior tension band) until the laminae were cut at the base. A bilateral open-door expansive laminotomy was then performed in standard fashion. Appropriate-sized HA spacers were selected, held with a specially designed holder, and placed between the split laminae. The screw holes were made in the laminae along the direction of the screw holes in the spacer, and two screws were inserted ventrolaterally to the laminae, resulting in instantaneous fixation. This procedure was performed in 15 patients; clinical results were successful, and there were no significant intraoperative complications. Follow-up radiological studies revealed no evidence of displacement of the spacers or screw backout. The screw artifacts observed on magnetic resonance imaging were minimal, allowing evaluation of the cervical spinal cord. The sagittal alignment of the cervical spine was well preserved. In the biomechanical studies the authors found that the screw fixation was of satisfactory strength, compared with other methods of fixation.
  
  
  CONCLUSIONS
  Bilateral open-door cervical expansive laminoplasty in which HA spacers are secured by titanium screws is a simple and quick method that yields sufficient fixation strength.
authors.affiliation: Department of Neurosurgery, Nagoya University School of Medicine, Japan. mtakayas@med.nagoya-u.ac.jp
authors.forename: Masakazu
authors.initials: M
authors.lastname: Takayasu
authors.forename: Teruhide
authors.initials: T
authors.lastname: Takagi
authors.forename: Toshihisa
authors.initials: T
authors.lastname: Nishizawa
authors.forename: Koji
authors.initials: K
authors.lastname: Osuka
authors.forename: Takehiko
authors.initials: T
authors.lastname: Nakajima
authors.forename: Jun
authors.initials: J
authors.lastname: Yoshida
mesh_terms: D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D001863:Bone Screws; D002574:Cervical Vertebrae / Q000473:pathology / Q000601:surgery*; D017886:Durapatite; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007796:Laminectomy / Q000295:instrumentation*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000175:diagnosis / Q000209:etiology; D019919:Prosthesis Implantation; D013117:Spinal Cord Compression / Q000175:diagnosis / Q000601:surgery; D013123:Spinal Fusion / Q000295:instrumentation*; D013128:Spinal Osteophytosis / Q000175:diagnosis / Q000601:surgery*; D013130:Spinal Stenosis / Q000175:diagnosis / Q000601:surgery*; D013525:Surgical Instruments; D014025:Titanium; D014057:Tomography, X-Ray Computed
chemical_list: D017886:Durapatite; D014025:Titanium