The aim of this study was to produce a simple and inexpensive technique for estimating the obturator foramen area (OFA) from young calves based on the hypothesis that OFA can be extrapolated from simple linear measurements. Three linear measurements - dorsoventral height, craneocaudal width and total perimeter of obturator foramen - were obtained from 55 bovine hemicoxae. Different algorithms for determining OFA were then produced with a regression analysis (curve fitting) and statistical analysis software. The most simple equation was OFA (mm2) = [3,150.538 + (36.111*CW)] - [147,856.033/DH] (where CW = craneocaudal width and DH = dorsoventral height, both in mm), representing a good nonlinear model with a standard deviation of error for the estimate of 232.44 and a coefficient of multiple determination of 0.846. This formula may be helpful as a repeatable and easily performed estimation of the obturator foramen area in young bovines. The area of the obturator foramen magnum can thus be estimated using this regression formula.
Biometry ; Foramen Magnum ; Nonlinear Dynamics ; Osteology

STUDY DESIGN: Retrospective chart review. PURPOSE: We sought to determine the differences in pedicle diameter (PD) in the lumbar spine between various races: ‘Asian,’ ‘Black,’ ‘White,’ and ‘Other.’ These data could aid in perioperative planning during instrumented spinal fusion. OVERVIEW OF LITERATURE: Recent literature underscores the importance of understanding diverse pedicle isthmus morphology to perform successful transpedicular procedures. These studies suggest that more detailed and reliable measurements of pedicles should be undertaken. However, none of the current literature comprehensively compares average PDs between diverse racial populations with a standardized study design. METHODS: Coronal cuts of 5,060 lumbar spine pedicles were inspected to obtain their transverse outer cortical PD as measured through the isthmus at L1–L5. Data were collected and categorized on the basis of patient-reported race. We examined average PD and PD range at each level for each race. To determine the significance, we used a mixed analysis of variance and a post hoc analysis. RESULTS: The Asian cohort consistently had a significantly smaller PD at L1–L5 than Blacks or Whites (p<0.001), as did the ‘Other’ group compared with Blacks (p<0.001) and Whites (p=0.032). At L1–L2, the ‘Other’ group showed the least variability in PD. At L3–L5, the Asian population showed the smallest range, and the Black population had the largest variability in PD except at L5. There was a significant difference in PD between the various races. CONCLUSIONS: The Asian population consistently has significantly smaller pedicles in the lumbar spine than the Black or White populations. This information could prove useful for surgical planning. We suggest using preoperative computed tomography for pedicle screw templating as a safe method for pedicle screw instrumentation with the highest pullout strength given the wide range of PD in the Black population and the variability of PD between races.
African Continental Ancestry Group ; Asian Continental Ancestry Group ; Cohort Studies ; Continental Population Groups ; Demography ; Humans ; Methods ; Orthopedics ; Osteology ; Pedicle Screws ; Retrospective Studies ; Spinal Fusion ; Spine