Vertebral height, disc height, posteroanterior displacement and dens-atlas gap in the cervical spine: precision measurement protocol and normal data.

摘要

Objective. (1) Precise measurement of vertebral height, disc height, posteroanterior displacement and dens-atlas gap from lateral radiographic views of the cervical spine. (2) Compilation of a normative database for these parameters, specifying dependence on gender and age.Design. Descriptive study, based on measurements from lateral radiographic views of the cervical spine of healthy subjects.Background. Normal data of vertebral height, disc height, posteroanterior displacement and size of the dens-atlas gap as well as their biological range of variation and potential dependence on gender and age are not available.Methods. Based on computer-aided measurements from lateral radiographic views of the cervical spine, a new protocol determines these parameters. Results are compensated for radiographic magnification, variation in stature and the individually adopted posture of the cervical spine; they are virtually uninfluenced by radiographic distortion and patient alignment errors. A specimen study as well as inter- and intra-observer studies quantify measurement errors.Results. Employing the new protocol, vertebral height C3-C7 and disc height C2/C3-C6/C7 are measured with relative errors of 3.9% and 5.7% respectively. Posteroanterior displacement C1/C2 to C6/C7 is measured with an error of 2.8% of mean vertebral depth and the dens-atlas gap is measured with an error of <1.8% of the depth of C2. A normal database for the dimensions of cervical vertebrae and discs as well as of the sagittal plane alignment of the vertebrae within the cervical spine is compiled from 135 lateral views of healthy adults.Conclusions. Vertebral height, disc height, posteroanterior displacement and size of the dens-atlas gap are measured with high precision. Normal data are presented for the first time.RelevanceThe new protocol in conjunction with the normal database enables future studies detecting or monitoring morphological effects of, for example, trauma, long-term high mechanical loading, disc degeneration, rheumatoid arthritis, fusion or other surgical interventions.