Correlation between leg pain at rest and spinal nerve edema in symptomatic lumbar foraminal stenosis

Background: Previous studies reported that spinal nerve edema on magnetic resonance myelography (MRM) and leg pain at rest were specifically observed in symptomatic lumbar foraminal stenosis patients. However, the correlation between leg pain at rest and spinal nerve edema in symptomatic foraminal stenosis has not been reported. Hypothesis: The purpose of this prospective study is to reveal a correlation between leg pain at rest and spinal nerve edema focusing on the pathophysiology of symptomatic foraminal stenosis. Patients and Methods: Clinical findings and MRM findings were surveyed among 30 patients with symptomatic foraminal stenosis diagnosed by MR imaging (MRI) and selective nerve root block. Comparisons of patient characteristics and clinical findings between the prevalence and absence groups of spinal nerve edema on MRM were analyzed. A correlation between the visual analogue scale (VAS) for leg pain at rest and the spinal edema ratio calculated as maximum intensity value of the affected spinal nerve/maximum intensity value of the asymptomatic side from region of interest (ROI) made on MRM was evaluated. Results: Twenty symptomatic foraminal stenosis cases (67%) showed the affected spinal nerve edema on MRM. The prevalence and VAS of leg pain at rest were significantly higher in the presence of spinal nerve edema group (95% and 67.0 ± 36.4, respectively). The correlation coefficient between the VAS for leg pain at rest (53.0 ± 33.6) and the spinal nerve edema ratio (1.3 ± 0.3) was 0.647 (p Discussion: Our study revealed the substantial correlation found between the spinal nerve edema ratio on MRM and the VAS for leg pain at rest in symptomatic foraminal stenosis. The correlation between spinal nerve edema and leg pain at rest has potential to clarify the pathology of symptomatic foraminal stenosis. Level of evidence: Ⅳ.