From the Guidelines
Somatosensory Evoked Potentials (SEPs) are a valuable diagnostic tool in cervical spondylosis, providing objective assessment of spinal cord function and nerve conduction, and should be used in conjunction with clinical examination and imaging studies for comprehensive evaluation. The role of SEPs in diagnosing and managing cervical spondylosis is to detect subclinical spinal cord compression, quantify the degree of neurological dysfunction, and monitor disease progression over time 1. SEPs measure electrical signals as they travel from peripheral nerves through the spinal cord to the brain, providing information about neural pathway integrity that cannot be obtained through imaging alone. Some key points to consider when using SEPs in cervical spondylosis include:
- The procedure involves placing electrodes on the scalp and stimulating peripheral nerves (typically median or tibial), then measuring the latency, amplitude, and waveform of the resulting signals.
- Abnormal findings such as prolonged latencies, reduced amplitudes, or absent responses indicate neurological compromise at specific spinal levels.
- SEPs are particularly useful for surgical planning, helping surgeons determine which levels require decompression, and for intraoperative monitoring to prevent iatrogenic injury during cervical spine procedures.
- They also provide prognostic information, as patients with minimal SEP abnormalities typically have better outcomes following decompressive surgery than those with severely abnormal or absent responses.
- While SEPs are sensitive for detecting posterior column dysfunction, they should be used in conjunction with clinical examination and imaging studies, such as MRI, for comprehensive evaluation of cervical spondylosis 1. It is essential to note that the diagnostic accuracy of SEPs can be influenced by various factors, including the presence of red flag symptoms, and the results should be interpreted in the context of the patient's overall clinical presentation 1. In terms of the current evidence, a recent study published in 2021 provides updated guidelines for the use of SEPs in the diagnosis and management of myelopathy, including cervical spondylosis 1. Overall, SEPs are a valuable diagnostic tool in cervical spondylosis, and their use in conjunction with clinical examination and imaging studies can provide a comprehensive evaluation of the condition and guide treatment decisions.
From the Research
Role of Somatosensory Evoked Potentials (SEPs) in Diagnosing Cervical Spondylosis
- SEPs can be used as a diagnostic aid in cervical spondylosis and spinal stenosis, as they may reflect nerve lesions caused by spondylotic deformities 2.
- SEP abnormalities are strongly correlated with clinical myelopathy, but not with radiculopathy, and can be used to detect posterior column involvement 3.
- SEPs may be more sensitive to sensory pathway involvement than clinical sensory testing in myelopathy cases 3.
SEPs in Clinical Management of Cervical Spondylosis
- SEPs can be used to detect subclinical posterior column involvement and to differentiate cervical spondylosis from other disorders such as multiple sclerosis and amyotrophic lateral sclerosis 3.
- However, the correlation of SEP findings with radiological data is generally poor, and SEP abnormalities can be detected in patients with clinical myelopathy but no radiological evidence of posterior cord compression 3.
- Motor evoked potentials (MEPs) may be more sensitive than SEPs in detecting myelopathy in its early stages 4.
Limitations and Future Directions
- Conventional MRI may not correlate well with functional deficits, and techniques such as myelin water imaging (MWI) may provide independent and complementary readouts to spinal cord compression 5.
- Further studies are needed to assess the value of SEPs in the clinical management of cervical spondylosis, particularly in relation to other diagnostic tools and treatment options 6, 4, 5.