Correlation of axial vertebral rotation with nerve root involvement: The first clinical study in literature

Abstract

Segmental instability is known as an underlying mechanism of degenerative vertebral and intervertebral disc changes. Based on a new finding an axially rotated lumbar vertebra may be occasionally spotted on lumbar magnetic resonance (MR) images obtained in non-weight-bearing position. This study was performed to examine the possibility of an association between this new finding and nerve root involvement in the lumbar spine. A total of 54 lumbar MR images of patients with signs of nerve root involvement in the lumbar spine were reviewed. An axially rotated lumbar vertebra was reported when at extreme parasagittal sections the posterior borders of two successive vertebral bodies were not aligned. Association of these rotations with radiculopathy and sensory/motor involvement in the corresponding regions in the lower extremity was examined. The mean pain severity was 7.59آ±2.10 (min-max: 3-10). There was a significant direct correlation between VAS and the linear amount of axial rotation (r = 0.73, p<0.001). There was also a significant, reverse correlation between the linear amount of axial rotation and the mean anteroposterior diameter of the neural foramen at the side of rotation (r = -0.91, p<0.001). Radiculopathy was concordant with axial rotation of the lumbar vertebrae in 88.9% of the cases. Both the linear amount of the axial vertebral rotation and anteroposterior diameter of the neural foramen were significantly associated with deficit in tactile sensation. Axial rotation of the lumbar vertebra is possibly an underlying cause of radiculopathy/back pain and sensory deficient in the lower extremities. This association is probably mediated with the involvement of neural elements in narrowed neural foramen at the side of rotation.