Changes in electromyographic results of patients with lumbar radiculopathy: a follow-up study

Serial electrodiagnostic testing: Utility and indications in adult neurological disorders

Although existing guidelines address electrodiagnostic (EDX) testing in identifying neuromuscular conditions, guidance regarding the uses and limitations of serial (or repeat) EDX testing is limited. By assessing neurophysiological change longitudinally across time, serial electrodiagnosis can clarify a diagnosis and potentially provide valuable prognostic information. This monograph presents four broad indications for serial electrodiagnosis in adult peripheral neurological disorders. First, where clinical change has raised suspicion for a new or ongoing lesion, EDX reassessment for spatial spread of abnormality, involvement of previously normal muscle or nerve, and/or evolving pathophysiology can clarify a diagnosis. Second, where diagnosis of a progressive neuromuscular condition is uncertain, electrophysiological data from a second time point can confirm or refute suspicion. Third, to establish prognosis after a static nerve injury, a repeat study can assess the presence and extent of reinnervation. Finally, faced with a limited initial study (as when complicated by patient or environmental factors), a repeat EDX study can supplement missing or limited data to provide needed clarity. Repeat EDX studies carry certain limitations, however, such as with prognostication in the setting of remote or chronic lesions, sensory predominant fascicular injury, or mild axonal injury. Nevertheless, serial electrodiagnosis remains a valuable and underused tool in the diagnostic and prognostic evaluation of neuromuscular conditions.

Role of paraspinal mapping before transforaminal epidural injections for lumbar radiculopathy

Objectives

This study aims to investigate whether electromyography (EMG) including paraspinal mapping (PM) and specific clinical findings before the injection have a predictive role on the results in patients undergoing unilateral transforaminal epidural steroid injection (TFESI).

Patients and methods

In this prospective study, a total of 46 patients (19 males, 17 females; mean age: 44.0±10.8 years; range, 23 to 60 years) with unilateral L5 root compression confirmed by physical examination, EMG and lumbar MRI between March 2013 and January 2014 were included. The patients underwent L5 TFESI. After the injection, they were examined at 1 h, three weeks, and three months.

Results

The clinical findings and presence of acute involvement on EMG were not predictive for TFESI results; however, the patients with lower scores for the L5 segment in PM benefited more from the injection, compared to patients with higher scores for the L5 segment in PM.

Conclusion

In patients with very clearly defined L5 radiculopathy, PM EMG can give us an idea about the effectiveness of L5 TFESI.

Can Foraminal Stenosis Due to Lumbar Isthmic Spondylolisthesis Cause Axonopathy in the Lower Extremity?

This study aimed to investigate, using electrodiagnosis, whether foraminal stenosis due to isthmic spondylolisthesis (IS) causes peripheral nerve axonopathy. We retrospectively reviewed the medical records of the Yeungnam University Hospital and included 46 patients (mean age = 60.8 ± 13.7 years; male:female = 24:22) with foraminal stenosis due to IS. We classified foraminal stenosis grading based on T2 and T1 sagittal spinal magnetic resonance imaging (MRI). Patients were divided into mild (n = 18) and severe foraminal stenosis (n = 28) groups. To evaluate axonopathy in the lower extremity, results of compound motor action potential (CMAP) of the extensor digitorum brevis muscle (EDB) and abductor hallucis brevis muscle (AHB), and sensory nerve action potential (SNAP) of the sural nerve were retrieved. No statistically significant difference was observed in the amplitude of CMAP of the EDB and AHB and SNAP of the sural nerve with the severity of foraminal stenosis. However, age showed a statistically significant relationship with the amplitude of NCS in the EDB, AHB, and sural nerves (p < 0.001). The severity of foraminal stenosis due to IS showed no relationship with axonopathy beyond age-related degeneration of the lower extremities. Therefore, if there is robust axonopathy in lower extremities, physicians should consider pathologies other than foraminal stenosis due to IS.

Evaluation of persons with suspected lumbosacral and cervical radiculopathy: Electrodiagnostic assessment and implications for treatment and outcomes (Part II)

The electrodiagnostic (EDX) examination with needle electromyography (EMG) is the most important means of testing for radiculopathy. This test has modest sensitivity but high specificity and complements imaging of the spine. In this second of a two-part review, the implications of electrodiagnostic findings for diagnosis and clinical management of persons with radiculopathy are reviewed. An EMG confirmed lumbosacral radiculopathy is associated with better clinical outcomes for persons undergoing aggressive conservative management. A positive EMG test portends a better clinical response to epidural corticosteroid injections. If a person undergoes spine surgery, a positive pre-operative EMG for radiculopathy is also associated with better outcomes.