title: An analysis of sagittal spinal alignment in 100 asymptomatic middle and older aged volunteers.
abstract: METHODS
  A radiographic evaluation of 100 adult volunteers over age 40 and without a history of significant spinal abnormality was done to determine indices of sagittal spinal alignment.
  
  
  OBJECTIVE
  To determine the sagittal contours of the spine in a population of adults older than previously reported in the literature and to correlate age and overall sagittal balance to other measures of segmental spinal alignment.
  
  
  BACKGROUND
  Previous studies of sagittal alignment have focused on adolescent and young adult populations before the onset of degenerative changes that may affect sagittal alignment.
  
  
  METHODS
  Radiographic measurements were collected and subjected to statistical analysis.
  
  
  RESULTS
  Mean sagittal vertical axis fell 3.2 +/- 3.2 cm behind the front of the sacrum. Total lumbar lordosis (T12-S1) averaged -64 degrees +/- 10 degrees. Lordosis increased incrementally with distal progression through the lumbar spine. Lordosis at L5-S1 and the position of the apices of the thoracic and lumbar curves were most closely correlated to sagittal vertical axis. Increasing age correlated to a more forward sagittal vertical axis with loss of distal lumbar lordosis but without an increase in thoracic or thoracolumbar kyphosis.
  
  
  CONCLUSIONS
  The majority of asymptomatic individuals are able to maintain their sagittal alignment despite advancing age. Loss of distal lumbar lordosis is most responsible for sagittal imbalance in those individuals who do not maintain sagittal alignment. Spinal fusion for deformity should take into account the anticipated loss of lordosis that may occur with age.
authors.affiliation: Department of Orthopaedic Surgery, Washington University Medical Center, St. Louis, Missouri, USA.
authors.forename: D E
authors.initials: DE
authors.lastname: Gelb
authors.forename: L G
authors.initials: LG
authors.lastname: Lenke
authors.forename: K H
authors.initials: KH
authors.lastname: Bridwell
authors.forename: K
authors.initials: K
authors.lastname: Blanke
authors.forename: K W
authors.initials: KW
authors.lastname: McEnery
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D005260:Female; D006801:Humans; D008161:Lumbosacral Region; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012016:Reference Values; D012727:Sex Characteristics; D013131:Spine / Q000000981:diagnostic imaging*; D013909:Thorax