title: Computed tomographic morphometric analysis of cervical pedicles in a multi-ethnic Asian population and relevance to subaxial cervical pedicle screw fixation.
abstract: OBJECTIVE
  Pedicle screw instrumentation provides optimal stabilization of the cervical spine complex, but is associated with risk of neurovascular injury. Sex and ethnic disparities may compromise safe and accurate screw placement. Therefore, a comprehensive analysis of pedicle dimensions derived from computed tomography scans is pertinent for our multi-ethnic population.
  
  
  METHODS
  Cervical spine CT of 50 patients without significant cervical spine pathology was selected. Pedicle width (PW), pedicle height (PH) and pedicle transverse angle (PTA) from C3 to C7 were measured and subsequently analyzed for sex and ethnic differences.
  
  
  RESULTS
  The smallest mean PW was at C4 in males and C3 in females. Mean PW for males was significantly greater than females at all levels (P < 0.05). 8 % of our population had at least one PW < 4.00 mm. At C5, C6 and C7 there is zero percent incidence of PW < 4.00 mm. The mean PH in males was significantly greater than females at all levels (P < 0.05), but no statistically significant sex differences in mean PTA values were found. There were significant ethnic differences in mean PW of males at C4, C5 and C7 (P < 0.05) and mean PH of females at C3, C4 and C7 (P < 0.05).
  
  
  CONCLUSIONS
  Transpedicular screw fixation is generally feasible in our population except for 8 % with at least one PW < 4.00 mm. However, in view of significant sex and ethnic morphometric variability, pre-operative CT evaluation together with image-guided screw placement is highly advised to ensure safety and accuracy.
authors.affiliation: Department of Neurosurgery, National Neuroscience Institute, 11, Jalan Tan Tock Seng, Singapore, 308433, Singapore, munusamy@cantab.net.
authors.forename: Thangaraj
authors.initials: T
authors.lastname: Munusamy
authors.forename: Ady
authors.initials: A
authors.lastname: Thien
authors.forename: Mark Gerad
authors.initials: MG
authors.lastname: Anthony
authors.forename: Ramesh
authors.initials: R
authors.lastname: Bakthavachalam
authors.forename: Shree Kumar
authors.initials: SK
authors.lastname: Dinesh
mesh_terms: D000328:Adult; D000368:Aged; D044466:Asian People; D002574:Cervical Vertebrae / Q000033:anatomy & histology* / Q000000981:diagnostic imaging* / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D065289:Pedicle Screws; D012727:Sex Characteristics; D012846:Singapore; D014057:Tomography, X-Ray Computed; D055815:Young Adult