The Role of EMG in Surgical Timing of Carpal Tunnel Syndrome

Background: Carpal tunnel syndrome (CTS) is the most common peripheral mononeuropathy caused by compression of the median nerve at the wrist inside the carpal tunnel.

Aim: The aim of this study was to investigate the relationship between EMG data and surgical success in patients with CTS who showed a decrease in conduction velocity and prolonged latency in EMG. Thus, it was aimed to link the surgical indications to objective criteria.

Patients and Methods: The patients who were diagnosed with carpal tunnel syndrome and  underwent surgery between 2013-2018 were evaluated prospectively. In the postoperative  12th month, changes in the median nerve velocity were observed by the EMG controls. Post-operative drowsiness was accepted as a surgical failure.

Results: 266 patients (62 males, 204 females) were included in the study. Complaints of 23 patients were continuing. The median motor latency average of the patients who complained was 6,63 msec (min 3,04 - max 11,04), and the message speed was 42,91 m / s (min 36,88 - max 51,8). Median nerve sensory potential was not found in 16 patients,  sensory and motor potential was not achieved in 2 patients. Median nerve sensory conduction could not be obtained in 70 of the patients without any complaint, but motor potential was obtained in all of patients. When median motor nerve latency was higher than 4.63 ms, it was found that the patient complaint of drowsiness continued after surgical treatment of CTS.

Conclusion: When the motor nerve Latans is above 4.63, the chance of success in the surgical treatment of CTS decreases. Performing CTS surgical treatment before these limits may prevent the occurrence of irreversible changes.