Can Sonography replace EMG and NCV in Carpal Tunnel Syndrome?
Ultrasound can show improvement of morphological criteria much earlier than the betterment of the function by electrodiagnostic tests like EMG and NCV in the postoperative follow up of CTS cases, according to a new study.
Winner of the AANS International Travel Scholarship, Ashraf A. El Badry, MD, IFAANS, presented his research, Can Sonography Replace Electromyography and Nerve Conduction Velocity in Carpal Tunnel Syndrome?, during the 2019 American Association of Neurological Surgeons (AANS) Annual Scientific Meeting.
This study was conducted to justify the efficacy of the ultrasonography (US) in the diagnosis of carpal tunnel syndrome (CTS) in the postoperative follow-up in comparison to electrodiagnostic tests, like electromyography (EMG) and nerve conduction velocity (NCV).
Electromyography (EMG) and nerve conduction velocity (NCV) are standard tests used for the diagnosis of carpal tunnel syndrome (CTS).
Carpal tunnel syndrome results from compression of the median nerve within the carpal tunnel. It is a cause of significant disability and is one of three common median nerve entrapment syndromes, the other two being anterior interosseous nerve syndrome and pronator teres syndrome.
In imaging median nerve syndromes, ultrasound is useful in examining carpal tunnel syndrome, potentially revealing, in fully developed cases, a triad of:
- palmar bowing of the flexor retinaculum (>2 mm beyond a line connecting the pisiform and the scaphoid)
- distal flattening of the nerve
- enlargement of the nerve proximal to the flexor retinaculum
One hundred CTS patients were documented through clinically, electrophysiologically and intraoperatively grading by using the Tuncali grading system (TGS), in Mansoura University Hospital, Insurance Hospital and EL Ahrar. All patients were evaluated pre and postoperatively by both the gold standard invasive electrodiagnostic (EMG, NCV) and the new noninvasive US tests.
US showed improvement of morphological criteria (within 3 weeks) than the betterment of the function by electrodiagnostic (after 6 months) in the postoperative follow up of CTS cases. Therefore, US examination for CTS can possibly be done without the need for other invasive investigations.
Author Block: Ashraf A. El Badry, MD, IFAANS (Mansoura City, Egypt, Arab Rep.)
Disclosure: The author reported no conflicts of interest.