title: Prevalence and type of cervical deformities among adults with Parkinson's disease: a cross-sectional study.
abstract: OBJECTIVE
  To identify the characteristics of cervical deformities in Parkinson's disease (PD) and the role of severity of PD in the development of cervical spine deformities, the authors investigated the prevalence of the cervical deformities, cervical kyphosis (CK), and cervical positive sagittal malalignment (CPSM) in patients with PD. They also analyzed the association of severity of cervical deformities with the stage of PD in the context of global sagittal spinopelvic alignment.
  
  
  METHODS
  This study was a prospective assessment of consecutively treated patients (n = 89) with PD. A control group of the age- and sex-matched patients was selected from patients with degenerative cervical spine disease but without PD. Clinical and demographic parameters including age, sex, duration of PD, and Hoehn and Yahr (H&Y) stage were collected. Full-length standing radiographs were used to assess spinopelvic parameters. CK was defined as a C2-7 Cobb angle < 0°. CPSM was defined as C2-7 sagittal vertical axis (SVA) > 4 cm.
  
  
  RESULTS
  A significantly higher prevalence of CPSM (28% vs. 1.1%, p < 0.001), but not CK (12% vs. 10.1%, p = 0.635), was found in PD patients compared with control patients. Among patients with PD, those with CK were younger (62.1 vs. 69.0 years, p = 0.013) and had longer duration of PD (56.4 vs. 36.2 months, p = 0.034), but the severity of PD was not significantly different. Logistic regression analysis revealed that the presence of CK was associated with younger age, higher mismatch between pelvic incidence and lumbar lordosis, and lower C7-S1 SVA. The patients with CPSM had significantly greater thoracic kyphosis (TK) (p < 0.001) and a trend toward more advanced H&Y stage (p = 0.05). Logistic regression analysis revealed that CPSM was associated with male sex, greater TK, and more advanced H&Y stage.
  
  
  CONCLUSIONS
  Patients with PD have a significantly higher prevalence of CPSM compared with age- and sex-matched control patients with cervical degenerative disease but without PD. Among patients with PD, CK is not associated with the severity of PD but is associated with overall global sagittal malalignment. In contrast, the presence of CPSM is associated more with the severity of PD than it is with the presence of global sagittal malalignment. Collectively, these data suggest that the neuromuscular pathogenesis of PD may affect the development of CPSM more than of CK.
authors.affiliation: Department of Medicine, Graduate School of Yonsei University, Seoul, Korea;
authors.forename: Bong Ju
authors.initials: BJ
authors.lastname: Moon
authors.affiliation: Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia;
authors.forename: Justin S
authors.initials: JS
authors.lastname: Smith
authors.affiliation: Department of Neurosurgery, University of California, San Francisco, California;
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Ames
authors.affiliation: Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia;
authors.forename: Christopher I
authors.initials: CI
authors.lastname: Shaffrey
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, New York;
authors.forename: Virginie
authors.initials: V
authors.lastname: Lafage
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, New York;
authors.forename: Frank
authors.initials: F
authors.lastname: Schwab
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Keio University, Tokyo, Japan and.
authors.forename: Morio
authors.initials: M
authors.lastname: Matsumoto
authors.affiliation: Department of Neurology, Sanggye Paik Hospital, Inje University College of Medicine and.
authors.forename: Jong Sam
authors.initials: JS
authors.lastname: Baik
authors.affiliation: Department of Neurosurgery, College of Medicine, Yonsei University, Seoul, Korea.
authors.forename: Yoon
authors.initials: Y
authors.lastname: Ha
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007738:Kyphosis / Q000453:epidemiology*; D008141:Lordosis / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D009333:Neck / Q000503:physiopathology; D010300:Parkinson Disease / Q000150:complications*; D011187:Posture / Q000502:physiology; D015995:Prevalence; D012600:Scoliosis / Q000453:epidemiology*; D013904:Thoracic Vertebrae / Q000503:physiopathology* / Q000601:surgery; D055815:Young Adult
keywords: CK = cervical kyphosis; CPSM = cervical positive sagittal malalignment; H&Y = Hoehn and Yahr; HRQOL = health-related quality of life; LL = lumbar lordosis; PD = Parkinson's disease; PI = pelvic incidence; PT = pelvic tilt; Parkinson's disease; SRS = Scoliosis Research Society; SVA = sagittal vertical axis; TK = thoracic kyphosis; UPDRS = Unified Parkinson's Disease Rating Scale; cervical kyphosis; cervical positive sagittal malalignment; deformity