Gravity determines the direction of nerve roots sedimentation in the lumbar spinal canal

Abstract

Objectives To investigate the role of gravity in the sedimentation of lumbar spine nerve roots using magnetic resonance (MR) imaging of various body positions. Methods A total of 56 patients, who suffered from back pain and underwent conventional supine lumbar spine MR imaging, were selected from sanmen hospital database. All the patients were called back to our hospital to perform MR imaging in prone position or lateral position. Furthermore, the sedimentation sign (SedSign) was determined based on the suspension of the nerve roots in the dural sac on cross-sectional MR images, and 31 cases were rated as positive and another 25 cases were negative. Results The mean age of negative SedSign group was significantly younger than that of positive SedSign group (51.7 ± 8.7 vs 68.4 ± 10.5, P < 0.05). The constitutions of clinical diagnosis were significantly different between patients with a positive SedSign and those with a negative SedSign (P < 0.001). Overall, nerve roots of the vast majority of patients (48/56, 85.7%) subsided to the ventral side of the dural sac on the prone MR images, although that of 8 (14.3%) patients remain stay in the dorsal side of dural sac. Nerve roots of only one patient with negative SedSign did not settle to the ventral dural sac, while this phenomenon occurred in 7 patients in positive SedSign group (4% vs 22.6%, P < 0.001). In addition, the nerve roots of all the five patients subsided to the left side of dural sac on lateral position MR images. Conclusions The nerve roots sedimentation followed the direction of gravity. Positive SedSign may be a MR sign of lumbar pathology involved the spinal canal.

The radio anatomical arrangement of nerve roots at L3 level in cauda equina sac is it affected by diseases?

“…Yang et al [6] demonstrated that nerve root position is affected by gravity during MRI examiantion. In the present study, all the patients were examined in the supine position; however, not all the patients had nerve roots in the same position.…”

“…of nerve roots Infront of the intertransverse process of L3, however; there was decreased reading of P value as we are moving down the table to started as0.427 in cases of single level prolapse to decrease gradually in the other conditions namely, the multiple prolapses and multiple bulges to start to has a statistically significant difference in the lower 3 pathological conditions as we mentioned above. Yang et al [6] demonstrated that nerve root position is affected by gravity during MRI examiantion. In the present study, all the patients were examined in the supine position; however, not all the patients had nerve roots in the same position.…”

“…Jun Yang et al confirmed that the cauda equina nerve roots follow the gravitational field during magnetic resonance imaging (MRI) examination; in their study, they called this the nerve root sedimentation sign. [6]…”

“…[5] Jun Yang et al confirmed that the cauda equina nerve roots follow the gravitational field during magnetic resonance imaging (MRI) examination; in their study, they called this the nerve root sedimentation sign. [6] Many conditions may affect lumbosacral spine integrity, such as disc protrusion. A herniated disc represent a complete rupture or tear of the annulus and a following leakage of the inner part of the disc.…”