Chemical radiculitis in lumbar spine / 中华骨科杂志

ABSTRACT

Objective The theory of chemical radiculitis was put forward about 30 years ago, but it has not been proved by clinical study so for. The current study was initiated to assess whether the annular tear in painful disc was the cause of radiating leg pain (radiculopathy) in patients with discogenic low back pain. Methods Forty-two patients with chronic low back pain in single level and shooting leg pain in unilateral or bilateral lower limbs without lumbar disc herniation on CT and MR imaging were treated (age range, 19-52 years; mean age, 34.9 years; 27 males, 15 females). All patients showed annular disruption and pain reproduction on injection of the contrast during discography at single disc level (not including patients who had two or three levels disc disease). CT scan was performed to identify the location of annular tears after discography. The examinations of electromyography(EMG) and motor nerve conduction velocity (MCV) were performed in all patients, which were used to analyze the degree of nerve root injury and the relation with radiating leg pain. Results The patients with posterolateral annular disruption in single side mainly presented single lower limb radiation pain, in contrast, the patients with posterolateral annular disruption in two sides or posterior midline annular disruption mainly presented dual lower limb radiation pain. There was a significant positive correlation between the site of annular tear and the side of radiation pain. The examinations of EMG in all 42 cases found that there were abnormal insertional activities such as fibrillation potentials and positive sharp waves in 32 cases(76%). Of the 23 patients with unilateral lower limb radiation, nerve root lesions were found on the symptomatic side in 17 cases(74%). Of the 19 cases with bilateral lower limb radiation pain, root lesions were suggested in 15 patients(79%). The conduction velocities of common peroneal nerve and tibial nerve decreased with a statistically significant difference in symptomatic side compared with normal side. Conclusion Inflammatory chemical mediators and cytokines produced in painful disc leaking into epidural space through annular tear could lead to the injury to adjacent nerve roots, which might be primary pathophysiologic mechanism for the production of chemical radiculitis.