Tr. Kuklo et al., Measurement of thoracic and lumbar fracture kyphosis - Evaluation of intraobserver, interobserver, and technique variability, SPINE, 26(1), 2001, pp. 61-65
Study Design. Statistical analysis of various measurement techniques for th
oracolumbar burst fracture kyphosis on lateral radiograph.
Objective. To determine the most reliable measurement technique.
Summary of Background Data, The treatment of thoracic and lumbar burst frac
tures involves many factors, including the degree of resultant kyphosis. Al
though various methods have been described, no study has directly compared
these methods for reliability and reproducibility.
Methods. Fifty lateral radiographs of thoracic and lumbar burst fractures w
ere randomly selected and measured on two separate occasions by three spine
surgeons using five different measurement techniques. Radiograph quality,
fracture type, and the center beam location were determined. Statistical an
alysis included analysis of variance for repeated measures and analysis of
variance using a generalized linear model.
Results. Intraclass correlation coefficients were most consistent for Metho
d 1 (rho = 0.83-0.94) followed by Method 4 (rho = 0.65-0.89) and Method 5 (
rho = 0.73-0.85). Intraobserver agreement (% of repeated measures within 5
degrees of the original measurement) ranged between 72% and 98% for all tec
hniques for all three observers, with Method 1 showing the best agreement (
84%-98%). Paired comparisons between observers varied considerably with int
erobserver reliability correlation coefficients ranging from 0.52 to 0.93.
Method 1 showed the highest interobserver reliability coefficient (0.81, ra
nge 0.71-0.93) followed by Method 5 (0.71, range 0.68-0.75). Method 1 also
had the highest percentage of agreement within categories (90% within 5 deg
rees).
Conclusions. Method 1 (measuring from the superior endplate of the vertebra
l body one level above the injured vertebral body to the inferior endplate
of the vertebral body one level below) showed the best intraobserver and in
terobserver reliability overall.