Abstract
Introduction
In general, the spinal cord was constricted at the level of spinal canal stenosis. Rarely, spinal cord curved above the level of stenosis like the slack rope. There was no report about this image we called slack spinal cord.
Material and Methods
Slack spinal cord was shown in 7 patients. The average age was 70 years old. Multiple spinal canal stenosis were shown at the junction of thoracolumbar spine. The level of the most cranial stenosis was L1/2; 4 patients and Th12/L1; 3 patient. 5 patients of them presented a symptom of lumbar spinal canal stenosis. 2 patients presented myelopathy.
Results
Laminectomy was performed for them. Slack spinal cord was improved after operation. The reasons of slack spinal cord were considered as moving the spinal cord to the cranial side or compressed by redundant spinal nerve roots. The denticulate ligaments are fibrous spinal structures that are generally believed to stabilize the spinal cord within the vertebral canal. In anatomical study, the structures of these ligaments were different in the spinal level. At the lower thoracic level, the denticulate ligament is thin and long band. Furthermore, the strength of this ligament is decreased at the lower spinal levels. Considering these anatomical characteristics and slack spinal cord is shown commonly at the caudal site of spinal cord, we guess the conus medullaris move to cranial side like redundant nerve root.
Conclusion
Slack spinal cord is rarely observed as the secondary change with spinal canal stenosis.