THE RELIABILITY OF PATIENT POSITIONING FOR EVALUATING STATIC RADIOLOGIC PARAMETERS OF THE HUMAN PELVIS

Objective: To determine the reproducibility of patient positioning on radiographically evaluated static configurations of the human pelvis. Design: Repeat anteroposterior radiography of the human pelvis was per formed in vivo. Comparative examinations were performed after 1 hr in one subject pool. A second sample underwent repeat examination after a mean of 18 days. Setting: Outpatient private practice chiropractic cl inic. Subjects: Thirty-seven relatively asymptomatic subjects particip ated in the experiment. Main Outcome Measures: Millimetric evaluations were made for leg length inequality, right/left sacral discrepancies and right/left innominate differences. The null hypothesis was that th e difference of the measurements from the two radiographs would be equ al to zero. A paired t-test was used to analyze if there were any sign ificant differences. The mean measured difference in millimeters and c orrelation coefficients were also determined for each variable. Result s: Individual variations for several roentgenometric parameters, inclu ding leg length inequality and pelvic torsion, did not reach statistic al significance (p > .05) although minor millimetric discrepancies wer e recorded. Correlation coefficients, in most cases, were relatively h igh. Conclusion: A subject can be reliably positioned for repeat anter oposterior pelvic radiography for both 1 hr and 18-day intervals. The methodology described has applicability to full spine radiography when roentgenometric parameters of the pelvis are scrutinized.