title: Predictive factors for a poor surgical outcome with thoracic ossification of the ligamentum flavum by multivariate analysis: a multicenter study.
abstract: METHODS
  Retrospective multi-institutional study.
  
  
  OBJECTIVE
  The purpose of this study was to describe the surgical outcomes in patients with ossification of the ligamentum flavum (OLF) and determine the influence of an ossified anterior longitudinal ligament (OALL) on the clinical features and surgical outcomes in thoracic OLF.
  
  
  BACKGROUND
  Detailed analyses of surgical outcomes of thoracic OLF have been difficult because of rarity of this disease.
  
  
  METHODS
  We identified 96 patients (77 males and 19 females with a mean age at surgery of 63.4 ± 10.3 yr) who underwent surgery for thoracic OLF and investigated their preoperative symptoms, severity of symptoms and myelopathy, disease duration, magnetic resonance imaging and computed tomographic findings, surgical procedure, intraoperative findings, and postoperative recoveries. The presence of OALL found at or near the most severely affected OLF level on sagittal computed tomographic images was classified into 1 of the following 4 types: (1) "no discernible type" (type N); (2) "one-sided type" (type O); (3) "discontinuous type" (type D); and (4) "continuous type" (type C). Multivariate logistic regression analysis was used to compute odds ratios and 95% confidence intervals to identify the risk factors associated with surgical outcomes.
  
  
  RESULTS
  The mean Japanese Orthopaedic Association score was 5.6 points preoperatively and 7.8 points 2 years postoperatively, yielding a mean recovery rate of 44.6%. Disease duration, presence of ossified dura mater, and type D OALL were the important factors for predicting surgical outcomes.
  
  
  CONCLUSIONS
  After evaluating surgical outcomes on the largest sample size of OLF surgical procedures thus far, our results show that disease duration, ossification of the dura mater, and the presence of type D OALL were risk factors related to surgical outcomes.
  
  
  METHODS
  3.
authors.affiliation: *Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Furo-cho, Chikusa-ku, Nagoya, Japan †Department of Orthopedic Surgery, Chubu Rosai Hospital, Nagoya City, Japan ‡Department of Orthopedic Surgery, Meijo Hospital, Nagoya City, Japan §Department of Orthopedic Surgery, Nagoya 2nd Red Cross Hospital, Nagoya City, Japan ¶Department of Orthopedic Surgery, Kariya-Toyota General Hospital, Kariya City, Japan ‖Department of Orthopedic Surgery, Konan Kosei Hospital, Konan City, Japan; and **Department of Orthopedic Surgery, Hamamatsu Medical University, Hamamatsu City, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Ando
authors.forename: Shiro
authors.initials: S
authors.lastname: Imagama
authors.forename: Zenya
authors.initials: Z
authors.lastname: Ito
authors.forename: Kenichi
authors.initials: K
authors.lastname: Hirano
authors.forename: Akio
authors.initials: A
authors.lastname: Muramoto
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Kato
authors.forename: Yasutsugu
authors.initials: Y
authors.lastname: Yukawa
authors.forename: Noriaki
authors.initials: N
authors.lastname: Kawakami
authors.forename: Koji
authors.initials: K
authors.lastname: Sato
authors.forename: Yuji
authors.initials: Y
authors.lastname: Matsubara
authors.forename: Tokumi
authors.initials: T
authors.lastname: Kanemura
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Matsuyama
authors.forename: Naoki
authors.initials: N
authors.lastname: Ishiguro
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007564:Japan; D017843:Ligamentum Flavum / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D016015:Logistic Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D019637:Orthopedic Procedures / Q000009:adverse effects*; D009999:Ossification, Heterotopic / Q000175:diagnosis / Q000601:surgery*; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000209:etiology* / Q000473:pathology; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D013122:Spinal Diseases / Q000175:diagnosis / Q000601:surgery*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome