title: Hydroxyapatite laminar spacers and titanium miniplates in cervical laminoplasty.
abstract: OBJECTIVE
  The authors describe a new surgical technique for cervical laminoplasty that was performed in 25 patients. The posterior elements along with the various ligaments are removed en bloc and are stabilized in a lift-up position by placing hydroxyapatite (HA) laminar spacers and titanium miniplates and screws. The procedure and clinical results are discussed.
  
  
  METHODS
  The posterior spinal elements, including the lamina(e), spinous process(es), and various attached ligaments, are removed en bloc by incising the lamina in its lateral aspect. Trapezoid-shaped HA spacers are placed between the cut ends of the laminae or between the laminae and lateral masses bilaterally at each level. Malleable titanium miniplates and screws are used for fixation of the spacers. The fixation of transected laminae was judged to be successful. Postoperative care included application of a soft neck collar for 1 week but no further restriction of activity. Surgery-related outcome was assessed in the 21 patients who attended more than 6 months of follow up after laminoplasty. There were 18 men and three women who ranged in age from 27 to 81 years. Cervical stenotic myelopathy was demonstrated in 15 patients who underwent decompressive and expansive laminoplasty, and spinal tumors were documented in six patients who underwent a nonexpansive laminoplasty. Postoperative and follow-up computerized tomography scans demonstrated no hardware failure. Bone formation around the spacers was observed either at 6- or at 9-month follow-up examination in all 21 patients. Fusion of the reconstructed laminae was found to be completed at 12 months in all 18 patients able to attend follow up for this duration. Spinal alignment and the range of motion of the cervical spine were well preserved. In patients with stenotic cervical myelopathy, neurological and anatomical outcome of canal expansion were satisfactory.
  
  
  CONCLUSIONS
  This technique enables rigid laminoplasty while maintaining anatomical and biomechanical integrity of posterior elements of cervical spine. Expansive and nonexpansive laminoplasty procedures are possible.
authors.affiliation: Department of Neurosurgery, Osaka City University Graduate School of Medicine, Medical School, Osaka, Japan.
authors.forename: Takeo
authors.initials: T
authors.lastname: Goto
authors.forename: Kenji
authors.initials: K
authors.lastname: Ohata
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Takami
authors.forename: Misao
authors.initials: M
authors.lastname: Nishikawa
authors.forename: Naohiro
authors.initials: N
authors.lastname: Tsuyuguchi
authors.forename: Michiharu
authors.initials: M
authors.lastname: Morino
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Matusaka
authors.forename: Akimasa
authors.initials: A
authors.lastname: Nishio
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Inoue
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Hara
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001672:Biocompatible Materials; D001860:Bone Plates; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D017886:Durapatite; D004867:Equipment Design; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures; D019736:Prostheses and Implants; D013125:Spinal Neoplasms / Q000601:surgery*; D013130:Spinal Stenosis / Q000601:surgery*; D014025:Titanium; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D001672:Biocompatible Materials; D017886:Durapatite; D014025:Titanium