[Research progress on nerve root sedimentation sign of lumbar spinal stenosis].

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.