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The potential for distortions due to variability in patient positioning substantiates challenges against radiographic evidence of vertebral realignments following chiropractic corrections. This paper describes a method to quantify patient positioning repeatability in Pre- and post-radiographs.


The method generates three variables of skeletal-landmark positional differences occurring between pre- and post-films: displacement, percent of rotational deviation, and percent of tube tilt deviation. A single analyst performed two separately blinded analysis rounds on 35 pairs of nasium films.


The mean differences, 95% confidence intervals, and standard deviations calculated for each variable from the two data sets were: for displacement, 0.24 mm ± 0.82 mm (SD 2.49 mm); for percent of rotational deviation, 1.08% ± 2.23% (SD 6.73%); and four percent of tube tilt deviation, 0.49% ± 1.04% (SD 3.13%).


The low intra-rater variability indicates that further analytical method development should produce a reliable, objective means to evaluate patient positioning repeatability in Pre and Post nasium X-rays.


Evidence that variability in patient positioning is controlled and minimized will enable precise quantitative determinations of the magnitude of corrections received by upper cervical chiropractic care patients.