title: Lower thoracic pedicle morphometry: male, taller, and heavier specimens have bigger pedicles.
abstract: METHODS
  An anatomic study of pedicle dimensions was performed for lower thoracic vertebrae from American human subjects.
  
  
  OBJECTIVE
  To quantify the dimensions of the lower thoracic pedicles and to better define the demographic factors that could ultimately govern the caliber selection of pedicle screws.
  
  
  BACKGROUND
  Transpedicular screw fixation allows for segmental instrumentation into multiple vertebrae across multilevel fusion area, offering considerable biomechanical advantage over the conventional hook and lateral mass fixation. Large variations in morphology from previous studies may be related to differences in demographics, sample size, and methodology.
  
  
  METHODS
  For this study, T7-T12 vertebrae from 503 American human cadavers were directly measured with a digital caliper. Examiner measured each vertebra to determine medial-lateral pedicle width and cranial-caudal pedicle height. Demographic information regarding age, sex, and race, as well as body height and weight, was available for all 503 subjects.
  
  
  RESULTS
  Both pedicle height and pedicle width generally increased in size caudally down the lower thoracic spine. The highest pedicle height was at the T12 level with a mean of 17.08 mm. The widest pedicle width was at the T11 level with a mean of 9.31 mm. Males have larger pedicles than females for all upper thoracic levels. The tallest and heaviest groups had larger pedicles than the shorter and lighter groups, respectively. Age and race did not consistently affect pedicle dimension in a statistically significant manner.
  
  
  CONCLUSIONS
  Our large-scale study of American specimens characterized the relationship between pedicle dimensions and a variety of demographic factors such as age, sex, body height and weight. With substantial statistical power, this study showed that male, taller, and heavier individuals had larger pedicles.
  
  
  METHODS
  N/A.
authors.affiliation: *Case Western Reserve University School of Medicine, Cleveland, OH †Department of Orthopedic Surgery, University of South Alabama School of Medicine, AL ‡Department of Orthopedic Surgery and Rehabilitation, Yale University School of Medicine, New Haven, CT §New Hampshire NeuroSpine Institute, Bedford, NH; and ¶Department of Orthopedic Surgery, University Hospitals Case Medical Center, Cleveland, OH.
authors.forename: Charles C
authors.initials: CC
authors.lastname: Yu
authors.forename: Roger T
authors.initials: RT
authors.lastname: Yuh
authors.forename: Navkirat S
authors.initials: NS
authors.lastname: Bajwa
authors.forename: Jason O
authors.initials: JO
authors.lastname: Toy
authors.forename: Uri M
authors.initials: UM
authors.lastname: Ahn
authors.forename: Nicholas U
authors.initials: NU
authors.lastname: Ahn
mesh_terms: D000293:Adolescent; D000328:Adult; D001741:Black or African American; D000368:Aged; D000369:Aged, 80 and over; D000886:Anthropometry; D001827:Body Height / Q000502:physiology*; D001835:Body Weight / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013904:Thoracic Vertebrae / Q000033:anatomy & histology*; D044465:White People; D055815:Young Adult