Diagnostic Role of Flexion-extension Central Motor Conduction Time in Cervical Spondylotic Myelopathy

Spine, 2021 · DOI: 10.1097/BRS.0000000000003706 · Published: November 1, 2021

Simple Explanation

Cervical spondylotic myelopathy (CSM) results from the spinal canal and cervical cord compression due to degenerative changes, often related to aging. MRI is used to diagnose cord compression, showing both static and dynamic compression during neck movements. Electrophysiological studies, like motor evoked potentials (MEP), assess central motor conduction, with central motor conduction time (CMCT) being a key indicator.

Study Duration

June 2017 to January 2020

Participants

227 patients with CSM

Evidence Level

Level 4, Retrospective study

Key Findings

1
CMCT was significantly delayed in both neck flexion and extension compared to the neutral neck position.
2
Patients with Muhle classification (MC) grades 1 and 2 showed significant delays in CMCT during flexion and extension.
3
More than one-third of patients with normal CMCT in neutral neck showed abnormal CMCT during neck flexion (35.3%) and extension (37.8%).

Research Summary

The study evaluated the diagnostic usefulness of flexion-extension CMCT in patients with CSM, comparing CMCT values across different neck positions and MRI findings. CMCT was significantly slower in neck flexion and extension compared to the neutral position, reflecting dynamic cervical cord impingement. Flexion-extension CMCT increases the sensitivity of CSM diagnosis, especially in mild to moderate cases, complementing dynamic MRI for a comprehensive assessment.

Practical Implications

Improved diagnostic accuracy

Flexion-extension CMCT can improve diagnostic accuracy in CSM, particularly in patients with mild to moderate disease severity.

Complementary diagnostic approach

Dynamic CMCT and dynamic MRI can be used together to provide a more comprehensive assessment of CSM.

Early detection of myelopathy

Dynamic CMCT can help detect myelopathy in patients with borderline CMCT values in the neutral neck position.

Study Limitations

1
The study only reviewed diagnostic usefulness with laboratory findings.
2
The CMCT measurement methods may not accurately reflect lesions below the C6/7 level.
3
The study only presented CMCT results of the upper limb.

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