New methods for diagnosing lumbar foraminal stenosis using dynamic digital tomosynthesis radiculography

The symptoms of lumbar radiculopathy, in particular foraminal stenosis, often exacerbated when the patient is upright. However, it is difficult to detect the compression of nerve roots while the patient is upright using conventional MRI. In this study, we analyzed the compression of lumbar nerve roots using dynamic digital tomosynthesis radiculography (DTRG) in patients diagnosed with lumbar radiculopathy. And we determined the relationship between leg pain and nerve compression while the patients are either prone or upright. We evaluated 30 patients with unilateral leg pain diagnosed as lumbar radiculopathy by physical examination and MRI. The patients were divided in two groups, one with foraminal stenosis (17 patients) and the other with canal stenosis (13 patients), based on MRI findings. All patients underwent DTRG to determine the diameter of their nerve roots in the foramen while prone and upright. Pain while prone or upright was assessed using a 100-point visual analogue scale (VAS) questionnaire. The VAS for leg pain while upright was significantly higher in the foraminal stenosis group (58 ± 24.7) than it was in the canal stenosis group (19.6 ± 13.2; p = 0.0002)). The nerve root diameter while prone or upright was significantly smaller in the foraminal stenosis group (1.2 ± 0.2 mm) than it was in the canal stenosis group (0.2 ± 0.1 mm; p < 0.0001). DTRG has the potential to visualize nerve compression while the patient is upright to reveal the relevance of foraminal stenosis to clinical findings. DTRG is useful for diagnosis of lumbar foraminal stenosis.