Anteroposterior diameter of the vertebral canal in cervical region: comparison of anatomical, computed tomographic, and plain film measurements.

The purpose was to compare the computed tomographic and plain film measurements with those of anatomical specimens to determine the antero-posterior diameter of the spinal canal in cervical region. Antero-posterior diameters of 75 cervical vertebral canals (15 sets of C3-C7) were measured anatomically at two different levels. Computed tomographic and plain film measurements were also obtained at the corresponding levels. Considering anatomical measurements as the gold standard, plain film and computed tomographic measurements were statistically compared. Interobserver and intraobserver differences were also evaluated. At the uppermost pedicle levels, there was no statistically significant difference between plain films and anatomical measurements, a good correlation. However, at lowermost pedicle level there was a statistically significant difference between plain films and anatomical measurements but not between tomographic and anatomical measurements. Our results suggest that plain films can accurately estimate cervical spinal canal mid-sagittal diameter at the uppermost pedicle level and be used as a first step examination for the evaluation of cervical spinal stenoses. Copyright 2001 Wiley-Liss, Inc.