Study Design: Prospective cohort design. Objective: To determine the diagnostic accuracy (sensitivity, specificity, positive and negative likelihood ratio) of 1 MHz conintuous therapeutic ultrasound in identifying median neuropathy at or distal to the wrist in a patient population. Background: Diagnosis and management of median neuropathy at or distal to the wrist (carpal tunnel syndrome) remains and expensive and often times perplexing endeavor. Diagnosis of median neuropathy at or distal to the wrist is primarily accomplished via clinical presentation, provacative tests and electrophysiological testing. While the senistivity and specificity of electrophysiological testing is relatively high, the monetary cost of performing these types of tests can be prohibitive as well as uncomfortable for the patient. A test that would provide for ease of use, patient comfort and provide high diagnostic accuracy would save money and time for both the patient and clinician. Therapeutic ultrasound applied to the median nerve at 1 megahertz has been proposed as a provacative test to elicit symptoms consistent with median neuropathy at or distal to the wrist. Methods: Forty two subjects with symptoms of pain, weakness, numbness or tingling that involved the hands, upper extremity or neck participated in this study. Continuous, 1 megahertz, therapeutic ultrasound was applied to the involved distal wrist over the margins of the carpal tunnel at four intensities for a duration of 5 seconds at each intensity. Subjects’ response to the ultrasound was recorded at each level. A postive response was recorded if the subject indicated any of the following: reproduction of their symptoms, numbness, tingling, pain/discomfort at the wrist or pain/discomfort radiating to the fingers. The diagnostic accuracy (sensitivity, specificity, positive and negative likelihood ratios) of the ultrasound test to detect median neuropathy at the wrist was calculated using nerve conduction velocity testing as the criterion standard. Conclusions: The diagnostic accuracy (sensitivity, specificity, positive and negative likelihood ratio) of 1 MHz continuous therapeutic ultrasound in identifying median neuropathy at or distal to the wrist in a patient population was found. The primary finding of this study was that a protocol utilizing therapeutic continuous ultrasound at 1 MHz was at least as effective in identifying subjects with median neuropathy at or distal to the wrist as common clinically utilized physical examination signs, but not as accurate as nerve conduction testing.
