Electrodiagnostic tests to confirm clinically suspected carpal tunnel syndrome

Abstract

Background: Compression of the median nerve at the wrist is the most common entrapment neuropathy. Patients present with sensory symptoms in the median nerve distribution, pain in the hand, wrist or forearm and weakness of thumb opposition or abduction in severe cases. The value of nerve conduction studies (NCS) in the diagnosis of carpal tunnel syndrome (CTS) is not clear. There are contradicting results from different reports, other reports citing the importance of electrodiagnostic (EDX) test in the diagnosis of CTS while other reports did not establish that link. In the Free State Province, patients with CTS are mainly managed by orthopaedic surgeons. Only a small proportion of patients are managed by neurosurgeons at Universitas Academic Hospital. The diagnosis is primarily made on clinical grounds. Conservative measures are tried first, but patients who do not respond to these, undergo carpal tunnel release surgery (CTRS). Objectives: The aim was to determine which EDX tests best correlate with the clinical diagnosis and severity of CTS. The objective was to establish EDX guidelines to be used in the neurology electrophysiology unit when diagnosing CTS. Method: A cross sectional analytic study. Patients with a diagnosis of CTS based on clinical signs and symptoms were recruited into the study from January 2019 to October 2019. They were requested to complete the Boston questionnaire (BQ) which assesses symptoms severity and functional capacity. Nine NC parameters were then tested and results compared with those from the BQ to determine whether they correlate. EDX severity score for CTS was assessed and was compared to the two components of the BQ. Results: Eighty-three percent of hands had severe to very severe symptoms on Boston 1 however, only 37.5% had severe to very severe functional impairment on Boston 2. Weighted kappa of 0.19 indicating no agreement between Boston 1 and 2, severe symptoms is not associated with an increase in functional impairment. No statistically significant correlation was found between EDX severity score, symptoms and functional status with a p value of 0.44 and 0.77 respectively. Conclusion: • There was no linear relationship between symptom severity and functional impairment; the majority of patients reported severe symptoms but no disability. • Clinical and EDX tests showed a weak positive correlation which is statistically insignificant. • Symptomatology rather than functional impairment was more indicative of severity of CTS. • No correlation was found between EDX tests, Boston 1 and Boston 2. • We were unable to answer with confidence the question of whether NCS is always necessary and feel that a follow-up post-op study will provide useful insights.