• Becker D
• Brewster A
• Greene-Orndorff L
• Theodossis C

• Gonstead Technique
• Pelvis / diagnostic imaging
• Subluxation

X-rays have long been used by chiropractors to assess for pathology and static bone position. The value of radiographs beyond pathology is predicated on the radiographs taken being an accurate representation of the patient’s anatomy, which can be altered by magnification and distortion errors that can occur in x-ray positioning. This study attempts to determine the clinical significance of x-axis translation positioning errors on pelvic measurements.

A lumbopelvic phantom spine encased in acrylic was x-rayed centered on the film, as well as in ¼-inch increments for 2 inches, in both left and right directions. Digital films were subsequently analyzed using computerized Gonstead line analysis to assess for sacrum and ilium measurements in each ¼ inch translation on the x-axis. Actual measurements were recorded, and Pearson correlations calculated.

For each inch of lateral translation, IN increased 2.50mm at the ipsilateral ilium while EX increased 2.50mm on the ilium contralateral to lateral translation. No significant change was noted in AS/PI measurements. Sacral posterior rotation increased 1.41mm ipsilaterally for each inch of x-axis translation.

Based on these results, it should be concluded that in most instances, errors in patient position that are 1 inch or less in lateral translation will have minimal to no effect on the overall listings, and are therefore likely not clinically significant.

Author keywords: Pelvic listings, Gonstead Technique, translation, x-ray, pelvic alignment, pelvis/diagnostic imaging, vertebral subluxation, mensuration

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