Objective To summarize the research progress on the nerve root sedimentation sign of lumbar spinal stenosis. Methods The recent domestic and foreign literature in recent years was reviewed. The definition, classification, and mechanism of nerve root sedimentation sign and the relation of nerve root sedimentation sign to diagnosis and treatment of lumbar spinal stenosis were summarized. Results Nerve root sedimentation sign is a phenomena which is found in MRI images of lumbar spine. Its mechanism is mainly increased intraoperative epidural pressure. There are two types of classification and the classification in which nerve root sedimentation sign is classified into " positive” and " negative” is widely applied. It has high sensitivity and specificity in differential diagnosis patients with severe lumbar spinal stenosis and patients with nonspecific low back pain. As for treatment, the nerve root sedimentation sign is related to the surgical disc levels. However, it’s not sure if the nerve root sedimentation sign is related to surgical outcome. In addition, a positive sedimentation sign turns negative after sufficient surgical decompression and a new positive sedimentation sign after sufficient decompression surgery could be used as an indicator of new stenosis in previously operated patients. Conclusion For lumbar spinal stenosis, the nerve root sedimentation sign can be applied as an auxiliary diagnostic indicator, as a guidance for deciding the operated disc levels, and as a postoperative indicator for evaluating the effectiveness.
ObjectiveTo explore the predictive value of the nerve root sedimentation sign in the diagnosis of lumbar spinal stenosis (LSS). Methods Between January 2019 and July 2021, 201 patients with non-specific low back pain (NS-LBP) who met the selection criteria were retrospectively analyzed. There were 67 males and 134 females, with an age of 50-80 years (mean, 60.7 years). Four intervertebral spaces (L1, 2, L2, 3, L3, 4, L4, 5) of each case were studied, with a total of 804. The nerve root sedimentation sign was positive in 126 intervertebral spaces, and central canal stenosis was found in 203 intervertebral spaces. Progression to symptomatic LSS was determined by follow-up for lower extremity symptoms similar to LSS, combined with central spinal stenosis. Univariate analysis was performed for gender, age, visual analogue scale (VAS) score for low back pain at initial diagnosis, treatment, dural sac cross-sectional area at each intervertebral space, number of spinal stenosis segments, lumbar spinal stenosis grade, positive nerve root sedimentation sign, and number of positive segments between patients in the progression group and non-progression group, and logistic regression analysis was further performed to screen the risk factors for progression to symptomatic LSS in patients with NS-LBP. ResultsAll patients were followed up 17-48 months, with an average of 32 months. Of 201 patients with NS-LBP, 35 progressed to symptomatic LSS. Among them, 33 cases also had central spinal stenosis, which was defined as NS-LBP progressing to symptomatic LSS (33 cases in progression group, 168 cases in non-progression group). Univariate analysis showed that CSA at each intervertebral space, the number of spinal stenosis segments, lumbar spinal stenosis grade, whether the nerve root sedimentation sign was positive, and the number of nerve root sedimentation sign positive segments were the influencing factors for the progression to symptomatic LSS (P<0.05); and further logistic regression analysis showed that positive nerve root sedimentation sign increased the risk of progression of NS-LBP to symptomatic LSS (OR=8.774, P<0.001). ConclusionThe nerve root sedimentation sign may be associated with the progression of NS-LBP to symptomatic LSS, and it has certain predictive value for the diagnosis of LSS.