Association of Complex Repetitive Discharges with Chronicity and Clinical Symptoms in Radiculopathies
Michael Skolka1, Reece Hass1, Devon Rubin2, Ruple Laughlin1
1Mayo Clinic Rochester, 2Mayo Clinic Florida
Objective:
This study aimed to clarify the clinical significance of complex repetitive discharges (CRDs) identified on needle electromyography (EMG) in patients with radiculopathies.
Background:
CRDs are incompletely understood spontaneous needle EMG waveforms that can be seen in both myopathic and neurogenic disorders including radiculopathies.
Design/Methods:
This case–control study randomly identified 100 patients with needle EMG evidence of radiculopathy demonstrating at least one CRD in the electrodiagnostically involved myotome between January 1, 2017 and January 1, 2022. These patients were compared with 100 randomly selected patients with EMG evidence of radiculopathy without CRDs matched to sex, age at EMG testing, and affected nerve root segment. Patient clinical symptoms, neurologic examination, EMG features, and imaging studies were analyzed. A paired sample t-test for continuous data and chi-square test for categorical data were used for statistical analysis with significance defined as p<0.05.
Results:
Patients with radiculopathies with CRDs had longer disease duration averaging 59 months (range 1–480) compared to patients with radiculopathies without CRDs averaging 26 months (range 1–192, p<0.01). Clinical symptoms of paresthesias and weakness were both significantly more common in patients with radiculopathies with CRDs than those patients without CRDs (p<0.01 and 0.01, respectively). Patients with radiculopathies with CRDs were referred more frequently for EMG testing specifically for a radiculopathy (p<0.01), had a higher average number of muscles with neurogenic motor unit potentials on EMG per radiculopathy (p=0.01), and had more evidence of active radiculopathies on EMG (p<0.01) compared with patients with radiculopathies without CRDs. Imaging studies of patients with radiculopathies with CRDs in the affected myotome were more likely to reveal evidence of potential nerve root compression (p<0.01).
Conclusions:
The presence of CRDs in patients with radiculopathies is consistent with clinically more symptomatic radiculopathies and a longer duration of nerve root compromise.