title: [Analysis of axial symptoms after indirect decompression for ossification of the posterior longitudinal ligament of the cervical spine].
abstract: OBJECTIVE
  To study the etiology and clinical significance of axial symptoms after posterior operative procedures for ossification of the posterior longitudinal ligament (OPLL).
  
  
  METHODS
  From February 2005 to February 2010, 76 patients with OPLL treated were retrospectively experienced. There were 34 male and 42 female with average of 52.1 years (range from 37 to 74 years), the average duration of the disease was 32.1 months (range from 11 to 56 months). Nineteen patients underwent traditional laminectomy in group A, 33 patients received open-door laminoplasty in group B and 24 patients underwent lateral mass screw fixation in group C. All patients underwent X-ray examination pre- and post operative, computed tomography were used for diagnosis of OPLL, the recovery rate was calculated using pre- and postoperative Japanese Orthopedic Association (JOA) scores for each patient. Pre- and postoperative cervical curvature index and axial symptoms were measured and compared. χ(2) test and SNK test were used as statistical methods.
  
  
  RESULTS
  All patients were followed up for 14 - 35 months, average (21 ± 5) months. Loss of cervical curvature index was 4.2% ± 1.7% in group A, 2.9% ± 2.2% in group B and 2.3% ± 1.9% in group C. The difference was significant in loss of cervical curvature indice between group A and B (q = 2.94, P < 0.01), group A and C (q = 4.23, P < 0.01). The average JOA recovery rate was 58.3% for group A, 64.3% for group B and 66.7% for group C. There was no significant difference in JOA recovery rate among the three groups (P > 0.05). The rate of early evident axial symptoms was 7/19 in group A, 30.3% in group B and 33.3% in group C and the difference was not statistically significant (P > 0.05). The incidence of late evident axial symptoms was 5/19 in group A, 12.1% in group B and 8.3% in group C, the difference was not significant between group B and C (χ(2) = 13.762, P < 0.01), but of statistical difference between group A and B(χ(2) = 6.368, P < 0.01), group A and C (χ(2) = 11.481, P < 0.01). No kyphotic deformity in the group A, no "Close Door" phenomenon in group B and no internal failure in group C.
  
  
  CONCLUSIONS
  The incidence of early axial symptoms are of no significant difference among the three groups, but late axial symptoms are higher in the laminectomy than other groups, which may be associated with loss of cervical lordosis.
authors.affiliation: Department of Spine Surgery, the Third Hospital of Hebei Medical University, Shijiazhuang 050051, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: Wen-yuan
authors.initials: WY
authors.lastname: Ding
authors.forename: Yong
authors.initials: Y
authors.lastname: Shen
authors.forename: Ying-ze
authors.initials: YZ
authors.lastname: Zhang
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Da-long
authors.initials: DL
authors.lastname: Yang
authors.forename: Ya-peng
authors.initials: YP
authors.lastname: Sun
authors.forename: Lin-feng
authors.initials: LF
authors.lastname: Wang
authors.forename: Lai-zhen
authors.initials: LZ
authors.lastname: Cao
authors.forename: Lei
authors.initials: L
authors.lastname: Ma
mesh_terms: D000328:Adult; D019299:Decompression, Surgical / Q000009:adverse effects* / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007796:Laminectomy / Q000009:adverse effects* / Q000379:methods; D008297:Male; D008875:Middle Aged; D017887:Ossification of Posterior Longitudinal Ligament / Q000601:surgery*; D011183:Postoperative Complications; D012189:Retrospective Studies