title: Neurological complications of cervical laminoplasty for patients with ossification of the posterior longitudinal ligament-a multi-institutional retrospective study.
abstract: METHODS
  Retrospective multi-institutional study.
  
  
  OBJECTIVE
  To investigate the incidence of neurological deficits after cervical laminoplasty for ossification of the posterior longitudinal ligament (OPLL).
  
  
  BACKGROUND
  According to analysis of long-term results, laminoplasty for cervical OPLL has been reported as a safe and effective alternative procedure with few complications. However, perioperative neurological complication rates of laminoplasty for cervical OPLL have not been well described.
  
  
  METHODS
  Subjects comprised 581 patients (458 men and 123 women; mean age: 62 ± 10 years; range: 30-86 years) who had undergone laminoplasty for cervical OPLL at 27 institutions between 2005 and 2008. Continuous-type OPLL was seen in 114, segmental-type in 146, mixed-type in 265, local-type in 24, and not judged in 32 patients. Postoperative neurological complications within 2 weeks after laminoplasty were analyzed in detail. Cobb angle between C2 and C7 (C2/C7 angle), maximal thickness, and occupying rate of OPLL were investigated. Pre- and postoperative magnetic resonance imaging was performed on patients with postoperative neurological complications.
  
  
  RESULTS
  Open-door laminoplasty was conducted in 237, double-door laminoplasty in 311, and other types of laminoplasty in 33 patients. Deterioration of lower-extremity function occurred after laminoplasty in 18 patients (3.1%). Causes of deterioration were epidural hematoma in 3, spinal cord herniation through injured dura mater in 1, incomplete laminoplasty due to vertebral artery injury while making a trough in 1, and unidentified in 13 patients. Prevalence of unsatisfactory recovery not reaching preoperative level by 6-month follow-up was 7/581 (1.2%). Mean occupying rate of OPLL for patients with deteriorated lower-extremity function was 51.2 ± 13.6% (range, 21.0%-73.3%), significantly higher than the 42.3 ± 13.0% for patients without deterioration. OPLL thickness was also higher in patients with deterioration (mean, 6.6 ± 2.2 mm) than in those without deterioration (mean, 5.7 ± 2.0 mm). No significant difference in C2/C7 lordotic angle was seen between groups.
  
  
  CONCLUSIONS
  Although most neurological deterioration can be expected to recover to some extent, the frequency of short-term neurological complications was higher than the authors expected.
authors.affiliation: Department of Orthopaedics, Jichi Medical University, Shimotsuke, Japan. seichi-spine@jichi.ac.jp
authors.forename: Atsushi
authors.initials: A
authors.lastname: Seichi
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Hoshino
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kimura
authors.forename: Shinnosuke
authors.initials: S
authors.lastname: Nakahara
authors.forename: Masahiko
authors.initials: M
authors.lastname: Watanabe
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Kato
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ono
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Kotani
authors.forename: Mamoru
authors.initials: M
authors.lastname: Mitsukawa
authors.forename: Kosei
authors.initials: K
authors.lastname: Ijiri
authors.forename: Norio
authors.initials: N
authors.lastname: Kawahara
authors.forename: Satoshi
authors.initials: S
authors.lastname: Inami
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Chikuda
authors.forename: Katsushi
authors.initials: K
authors.lastname: Takeshita
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Nakagawa
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Taguchi
authors.forename: Masashi
authors.initials: M
authors.lastname: Yamazaki
authors.forename: Kenji
authors.initials: K
authors.lastname: Endo
authors.forename: Hironobu
authors.initials: H
authors.lastname: Sakaura
authors.forename: Kenzo
authors.initials: K
authors.lastname: Uchida
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Kawaguchi
authors.forename: Masashi
authors.initials: M
authors.lastname: Neo
authors.forename: Masahito
authors.initials: M
authors.lastname: Takahashi
authors.forename: Katsumi
authors.initials: K
authors.lastname: Harimaya
authors.forename: Hideo
authors.initials: H
authors.lastname: Hosoe
authors.forename: Shiro
authors.initials: S
authors.lastname: Imagama
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Taniguchi
authors.forename: Takui
authors.initials: T
authors.lastname: Ito
authors.forename: Takashi
authors.initials: T
authors.lastname: Kaito
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Chiba
authors.forename: Morio
authors.initials: M
authors.lastname: Matsumoto
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Toyama
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007796:Laminectomy / Q000009:adverse effects* / Q000379:methods; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009422:Nervous System Diseases / Q000209:etiology*; D017887:Ossification of Posterior Longitudinal Ligament / Q000601:surgery*; D011183:Postoperative Complications / Q000209:etiology*; D012189:Retrospective Studies; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome