title: Ossification of the posterior longitudinal ligament of the cervical spine in 3161 patients: a CT-based study.
abstract: METHODS
  A cross-sectional study.
  
  
  OBJECTIVE
  To examine the prevalence of ossification of the posterior longitudinal ligament (OPLL) and ossification of the nuchal ligament (ONL) of the cervical spine in the San Francisco area.
  
  
  BACKGROUND
  The prevalence of OPLL and ONL is unknown in the non-Asian population.
  
  
  METHODS
  This computed tomography-based cross-sectional study assessed the prevalence of OPLL and ONL within the cervical spine of patients treated at a level 1 trauma center between 2009 and 2012. The prevalence of both OPLL and ONL was compared between racial groups.
  
  
  RESULTS
  Of the 3161 patients (mean age, 51.2 ± 21.6 yr; 66.1% male), there were 1593 Caucasians (50.4%), 624 Asians (19.7%), 472 Hispanics (14.9%), 326 African Americans (10.3%), 62 Native Americans (2.0%), and 84 Others (2.7%). The prevalence of cervical OPLL was 2.2% (95% confidence interval [CI]: 1.7-2.8). The adjusted prevalence was 1.3% in Caucasian Americans (95% CI: 0.7-2.3), 4.8% in Asian Americans (95% CI: 2.8-8.1), 1.9% in Hispanic Americans (95% CI: 0.9-4.0), 2.1% in African Americans (95% CI: 0.9-4.8), and 3.2% in Native Americans (95% CI: 0.8-12.3). The prevalence of OPLL in Asian Americans was significantly higher than that in Caucasian Americans (P = 0.005). ONL was detected in 346 patients and the prevalence was 10.9% (95% CI: 10.0-12.0). The adjusted prevalence of ONL was 7.3% in Caucasian Americans (95% CI: 5.8-9.3), 26.4% in Asian Americans (95% CI: 21.9-31.5), 7.4% in Hispanic Americans (95% CI: 5.2-10.5), 2.5% in African Americans (95% CI: 1.2-4.9), and 25.8% in Native Americans (95% CI: 16.5-37.5). ONL was significantly more common in Asian Americans than in Caucasian Americans, Hispanic Americans, and African Americans (P = 0.001).
  
  
  CONCLUSIONS
  This study also demonstrated that OPLL and ONL were significantly more common in Asian Americans than in Caucasian Americans.
  
  
  METHODS
  3.
authors: *Department of Orthopedic Surgery, Osaka University Graduate School of Medicine, Osaka, Japan †Department of Orthopedic Surgery, University of California San Francisco, San Francisco, CA ‡Department of Orthopedic Surgery, Sumitomo Hospital, Osaka, Japan §Department of Radiology, University of California San Francisco, San Francisco, CA ¶Department of Orthopedic Surgery, San Francisco General Hospital, San Francisco, CA; and ∥Department of Biomedical Statistics, Osaka University Graduate School of Medicine, Osaka, Japan.
authors: Takahito
authors: T
authors: Fujimori
authors: Hai
authors: H
authors: Le
authors: Serena S
authors: SS
authors: Hu
authors: Cynthia
authors: C
authors: Chin
authors: Murat
authors: M
authors: Pekmezci
authors: William
authors: W
authors: Schairer
authors: Bobby K
authors: BK
authors: Tay
authors: Toshimitsu
authors: T
authors: Hamasaki
authors: Hideki
authors: H
authors: Yoshikawa
authors: Motoki
authors: M
authors: Iwasaki
mesh_terms: D000293:Adolescent; D000328:Adult; D001741:Black or African American; D000368:Aged; D000369:Aged, 80 and over; D001213:Asian; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging*; D003430:Cross-Sectional Studies; D005260:Female; D006630:Hispanic or Latino; D006801:Humans; D007198:Indians, North American; D008023:Ligaments, Articular / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D017887:Ossification of Posterior Longitudinal Ligament / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D009999:Ossification, Heterotopic / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D015995:Prevalence; D012495:San Francisco / Q000453:epidemiology; D013131:Spine / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed; D044465:White People; D055815:Young Adult