title: Quantifying the effects of age, gender, degeneration, and adjacent level degeneration on cervical spine range of motion using multivariate analyses.
abstract: METHODS
  Retrospective review and multivariate analysis.
  
  
  OBJECTIVE
  Assess cervical spine segmental range of motion (ROM) with flexion/extension (F/E) radiographs and determine the relation to clinical variables.
  
  
  BACKGROUND
  Previous studies investigated the roles of age and degeneration on cervical ROM with univariate analyses. Multivariate analyses are required to account for multiple factors that may affect ROM and quantify their relative effects.
  
  
  METHODS
  Radiographs of 195 patients were analyzed, including 133 females and 62 males with ages ranging from 15 to 93 years. Segmental ROM and Kellgren score (KS) of degeneration were assessed for C2-C7. Patient's age and gender were documented. Multivariate analyses were performed for each level. Independent variables evaluated were: (1) KS at the level of interest, (2) KS at the level above, (3) KS at the level below, (4) age, and (5) gender. Significance was defined as P < 0.05.
  
  
  RESULTS
  Interobserver reliabilities for assessing KS (intraclass correlation coefficient 0.81) and segmental ROM (intraclass correlation coefficient 0.72) were good to excellent. Age had a significant negative association with ROM at C2-C3, C3-C4, C4-C5, and C5-C6. KS at the level of interest had a significant negative association with ROM at C2-C3, C3-C4, C4-C5, C5-C6, and C6-C7. KS at the inferior segment had a significant positive association with ROM at C2-C3, C3-C4, and C4-C5. Gender had a significant association with ROM only at C2-C3.
  
  
  CONCLUSIONS
  Age was associated with declining ROM independent of degeneration, amounting to a 5 degrees decrease in subaxial cervical ROM every 10 years. Degeneration was also associated with ROM. For every point increase in KS at a given level, there was an associated 1.2 degrees decrease in ROM at that level, and a 0.8 degrees increase in ROM at the level above. These results provide a framework with which to counsel patients about cervical ROM and a benchmark from which procedure specific changes can be compared.
authors.affiliation: Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, CT 06520-8071, USA.
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Simpson
authors.forename: Debdut
authors.initials: D
authors.lastname: Biswas
authors.forename: John W
authors.initials: JW
authors.lastname: Emerson
authors.forename: Brandon D
authors.initials: BD
authors.lastname: Lawrence
authors.forename: Jonathan N
authors.initials: JN
authors.lastname: Grauer
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000502:physiology*; D005260:Female; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D015588:Observer Variation; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology*; D012189:Retrospective Studies; D012737:Sex Factors