title: Spinous process morphology: the effect of ageing through adulthood on spinous process size and relationship to sagittal alignment.
abstract: METHODS
  Blinded radiographic analysis of CT scans reformatted for precise lumbar spinous process (LSP) measurement.
  
  
  OBJECTIVE
  To investigate the effect of ageing on LSP morphology and influence of LSP morphology on lumbar spine sagittal alignment.
  
  
  BACKGROUND
  There is little data reporting the influence of ageing on spinous process size. There is data describing the increase in size of other body parts with age, such as the femur, ears, vertebral body, and nose. Several old cadaveric and radiographic studies have reported the formation of osseous spurs within the supraspinous and interspinous ligaments.
  
  
  METHODS
  200 abdominal CT scans taken for trauma and vascular investigation were reformatted to allow precise bony measurement of the lumbar spine. Two observers were blinded from the age and demographics of the patients. Sagittal and coronal plane projections were used to measure the height and width of the spinous processes (L1-L5), respectively. The relationship between spinous process size, age, and supine lordosis was investigated.
  
  
  RESULTS
  LSP height increases by 0.03-0.07 mm/year (p < 10(-3) to 10(-8)) and width by 0.05-0.06 mm/year (p < 10(-11) to 10(-15)). Lumbar lordosis decreases with increasing LSP height (p < 0.0004) but is not related to increasing LSP width (p = 0.195). Supine lordosis increases by 0.1°/year (p = 0.004).
  
  
  CONCLUSIONS
  This study demonstrates that the dimensions of the LSP change with age. Increases in LSP height and even more impressive increases in LSP width occur with advancing age. There is an inverse relationship between lumbar lordosis and LSP height.
authors.affiliation: Department of Orthopaedics, Auckland City Hospital, Level 7, Auckland, New Zealand. caspar@doctors.net.uk
authors.forename: Caspar Edward William
authors.initials: CE
authors.lastname: Aylott
authors.forename: Rupesh
authors.initials: R
authors.lastname: Puna
authors.forename: Peter Alexander
authors.initials: PA
authors.lastname: Robertson
authors.forename: Cameron
authors.initials: C
authors.lastname: Walker
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology*; D005260:Female; D006801:Humans; D015994:Incidence; D008141:Lordosis / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000473:pathology; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D054850:Osteophyte / Q000000981:diagnostic imaging / Q000473:pathology*; D011187:Posture; D014057:Tomography, X-Ray Computed; D055815:Young Adult