Although previous studies have shown poor correlation between clinical symptoms due to lumbar stenois and radiologic stenosis, no study has corrected for congenital variation in vertebral body size among individuals. This purpose of this study is to determine the relationship between the degree of radiographic lumbar spinal stenosis, adjusted with an internal control for vertebral body size, and disability from lumbar stenosis.

One hundred and twenty-three consecutive patients with clinical and radiologic confirmation of neural impingement secondary to lumbar stenosis were enrolled prospectively. Thecal sac AP diameter (TSD) and cross sectional area (CSA), and vertebral body AP dimension (VBD) were determined. These parameters were then correlated with patients’ symptoms using the modified Roland-Morris Questionnaire (RMQ) disability score.

This study found no statistically significant inverse correlation between TSD and RMQ score (p=0.433) or CSA and RMQ Score (p=0.124). In addition, there was no significant inverse correlation between CSA/VBD ratio and RMQ score (p=0.036) or TSD/VBD ratio and RMQ score (p=0.109). There was a significant difference in mean RMQ scores when the patients were divided into those with CSA greater than or equal to 70 mm2 and those less than 70 mm2, with T=−2.104 and p=0.038.

The degree of radiographic lumbar spinal stenosis, even with the use of an internal control of vertebral body size and standardized disability questionnaires, does not correlate with clinical symptoms. However, patients with more severe stenosis below a cross-sectional area critical threshold of 70mm2, have significantly greater functional disability.