The contribution of neurophysiology in the diagnosis and management of cervical spondylotic myelopathy: a review

Abstract

Neuroimaging, especially magnetic resonance imaging, represents the procedure of choice for the diagnosis of CSM, but a correct interpretation of morphological findings can be achieved only if they are correlated with functional data. The studies reported in this review highlight the crucial role of the electrophysiological studies in diagnosis and management of CSM.

Abnormal central motor conduction at the upper but not lower limbs correlates with severe cervical spondylosis: discussion of an unexpected observation

“…This belief is supported by many published studies. [2][3][4][5] Under time pressure one might opt to study CMCT to the lower limbs only, assuming that if it is normal then CMCT to the upper limbs should be normal as well. Here initial evidence is provided against this belief.…”

“…4,9,10,11 It has been suggested that when there is a close correlation between MRI and TMS findings, the most important etiological factor may be probably a segmental demyelination of central motor pathways due to a direct mechanical spinal cord compression. When discrepancies between the level of spinal cord compression documented by neuroimaging studies and the level of spinal cord dysfunction revealed by TMS are observed, 3,12 more mechanisms come into play. A more caudal functional involvement of the cervical cord revealed by TMS has been attributed to compromised blood flow to the spinal cord.…”

“…When cervical spondylotic compression involves the anterior spinal artery, the major damage is of vascular origin and localized to lower cervical segments, independent from the level of spondylotic degenerative changes. 3,13 These observations are mostly based on evidence stemming from small, older anatomical studies; hence, more work is needed to fully elucidate the pathophysiological mechanisms involved in CSM. Nevertheless, histological findings of both spinal cord ischemia and demyelination have been found in autopsy material in said studies, 14,15 alluding to the fact that both these mechanisms come into play in CSM.…”

“…1 CMCT is sensitive in detecting cervical spondylotic myelopathy (CSM), which is caused by compression of the cervical spinal cord by spondylotic changes, while it correlates with the severity of cord compression. [1][2][3] CMCT to lower limb muscles is more sensitive and is earlier affected, while upper limb CMCT is affected later in the course of CSM and indicates more severe disease. 4,5 It was observed in a minority of patients seen in our laboratory that CMCT to the upper limbs was abnormal, while that to the lower limbs was normal.…”

Magnetospinography visualizes electrophysiological activity in the cervical spinal cord

“…It has been used not only for intraoperative monitoring, but also for preoperative assessment to diagnose spinal lesions responsible for myelopathy and to predict progression to myelopathy in asymptomatic cases 16–21 . However, electrophysiological activity recorded at the body surface is not particularly suitable for recording conductive activity in deep and complex structures such as the spinal cord, spinal nerve and brachial plexus.…”