MEASUREMENT OF LUMBAR LORDOSIS - EVALUATION OF INTRAOBSERVER, INTEROBSERVER, AND TECHNIQUE VARIABILITY

Study Design. Sixty radiographs were measured on two separate occasion s by three physicians using four different techniques to evaluate the reliability and reproducibility of the measurement of lumbar lordosis. Objective. To evaluate clinical methods of measuring lumbar lordosis, determining intraobserver and interobserver reliability. Summary of B ackground Data. Several different methods are used to measure lumbar l ordosis. The reliability and reproducibility of these has not been wel l studied. Methods. Sixty lateral full spine radiographs were obtained , labeled, and the lumbar lordosis measured independently by three pra ctitioners who routinely perform these measurements. Four measurement techniques were used. These included measurements from the inferior en dplates of T12 to the superior endplate of S1; the superior endplate o f L1 to the superior endplate of S1; the inferior endplate of T12 to t he inferior endplate of L5; and the superior endplate of L1 to the inf erior endplate of L5. The measurements then were repeated after relabe ling. Results. Intraobserver reliability coefficients ranged from 0.83 to 0.92, indicating excellent reproducibility. Ninety-two percent of repeat measures were within 10 degrees. High overall and pairwise agre ement among the three observers also was present; the interobserver re liability coefficients ranged from 0.81 to 0.92. Conclusions. The meas urement of lumbar lordosis is reproducible and reliable if the techniq ue is specified and one accepts 10 degrees as acceptable variation. Fa ctors that affect the reproducibility of measurement include end verte bra selection (especially with transitional segments) and vertebral en dplate architectura.