Correlation between Severity of Intervertebral Disc Herniation and Electrodiagnostic Findings in the S1 Radiculopathy

OBJECTIVE: To compare the results of electrodiagnostic studies with the severity of disc herniation, measured digitally by picture archiving and communication system (PACS) from the images of magnetic resonance imaging (MRI). METHOD: MRI images were reviewed from thirty two patients who were diagnosed electrodiagnostically as unilateral S1 radiculopathy. Areas of herniated disc and spinal canal were measured and the ratio of disc herniation was calculated from the axial images stored and analyzed by PACS. The radiologic measurements were compared with the results of electrodiagnostic studies. RESULTS: The presence of abnormal spontaneous activities in needle EMG and no response in H reflex were associated with larger disc herniation (p<0.05). There was no other single electrodiagnostic study that showed correlation with any of radiologic measurements. With increasing number of abnormal electrodiagnostic tests, area of disc herniation grew larger (p<0.05). Area of spinal canal and the ratio of disc herniation did not show difference between normal and abnormal groups in most of electrodiagnostic studies. CONCLUSION: There were limited correlations between electrodiagnostic results and severity of disc herniation. The size of disc herniation, regardless of the size of spinal canal, was associated with abnormal results of electrodiagnostic tests.

Follow Up of Asymptomatic Hands in the Patients with Unilateral Carpal Tunnel Syndrome

OBJECTIVE: To know whether nerve conduction study (NCS) could predict later development of carpal tunnel syndrome (CTS) in asymptomatic hands of the patients with unilateral CTS. METHOD: Thirty four patients with unilateral CTS were studied. Subjects were divided into groups with or without the delay of latency, based on the results of initial NCS of asymptomatic hands. After follow up for more than 6 months clinically and electrodiagnostically, the development of CTS in initially asymptomatic hands was compared between groups. RESULTS: At follow up, CTS was diagnosed in 83% of the subjects in the group with motor latency delay at first study, while it was diagnosed in 32% of the subjects in the group without motor latency delay. In the group with sensory latency delay at first study, CTS was diagnosed in 78% of subjects at follow up, whereas only 19% of the subjects developed CTS in the group without sensory latency delay. The incidence of CTS at follow up was significantly higher in the group with motor or sensory latency delay at first study. CONCLUSION: In unilateral CTS, latency delay in motor or sensory NCS of asymptomatic hands may suggest a greater risk of later development of CTS.