Plain film assessment of spinal stenosis: method comparison with lumbar CT

Methods to determine the sagittal diameter of spinal canal on plain film radiographs have been previously proposed by Eisenstein in 1975 and Buehler in 1978. The purpose of this study was to determine the accuracy of these methods as compared to computed tomography (CT) and to compare the accuracy of each method. The AP diameter of the lumbar canal was evaluated at the L3 through L5 levels. Results indicate that the Buehler method was significantly (p less than or equal to 0.05) more accurate than Eisenstein method at the L3 level. At L4 and L5, there were no significant (p less than or equal to 0.01 p less than or equal to 0.20, respectively) differences between either of the plain film measurements and the mean value of the corresponding CT scans. The standard deviation (SD) showed less dispersity of the measurements with the Buehler method at all three levels examined.