title: Population reference range for developmental lumbar spinal canal size.
abstract: BACKGROUND
  Considerable variability exists in normal developmental lumbar spinal canal size. This impacts the likelihood of neural compromise. Spinal canal development is complete by 17 years. As diseases incurred thereafter do not knowingly affect the developmental size of the spinal canal, it is reasonable to use a selected population undergoing abdominopelvic computed tomography (CT) examination to determine developmental lumbar spinal canal size.
  
  
  METHODS
  Study approval was granted by the Clinical Research Ethics Committee. Between Feb 2014 and Jan 2015, mid-vertebral spinal canal cross-sectional area (CSA), depth, width, and vertebral body CSA at each level from L1-L5 was measured, using a semi-automated computerized method in 1,080 ambulatory patients (540 males, 540 females, mean age, 50.5±17 years). Patient height and weight was measured.
  
  
  RESULTS
  A reference range for developmental lumbar spinal canal dimensions was developed at each lumbar level for each sex. There was a 34% variation in spinal canal CSA between smallest and largest quartiles. Developmental spinal canal CSA and depth were consistently smallest at L3, enlarging cranially and caudally. Taller people had slightly larger lumbar spinal canals (P<0.0001). Males had larger spinal canal CSAs than females though relative to vertebral body CSA, spinal canal CSA was larger in females. There was no change in spinal canal CSA with age, weight or BMI (P<0.05).
  
  
  CONCLUSIONS
  A population reference range for developmental lumbar spinal canal size was developed. This allows one to objectively determine the degree of developmental spinal canal stenosis present on an individual patient basis.
authors.affiliation: Department of Imaging and Interventional Radiology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: James F
authors.initials: JF
authors.lastname: Griffith
authors.affiliation: Department of Imaging and Interventional Radiology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Junbin
authors.initials: J
authors.lastname: Huang
authors.affiliation: Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Sheung-Wai
authors.initials: SW
authors.lastname: Law
authors.affiliation: Department of Imaging and Interventional Radiology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Fan
authors.initials: F
authors.lastname: Xiao
authors.affiliation: Jockey Club Centre for Osteoporosis Care and Control, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Jason Chi Shun
authors.initials: JC
authors.lastname: Leung
authors.affiliation: Department of Imaging and Interventional Radiology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Defeng
authors.initials: D
authors.lastname: Wang
authors.affiliation: Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Shi
keywords: Lumbar spine; computed tomography (CT); developmental stenosis; population; reference range; spinal canal