The differences between ES-CMAP and CMS-CMAP recorded either from esophageal or chest wall electrodes make CMS unreliable for the measurement of phrenic nerve conduction time. Good-quality CMS-CMAPs could be recorded in some subjects from an electrode positioned very low in the esophagus. The amplitude of the CMS-CMAP (1.00 ± 0.15 mV) was much higher than that of ES-CMAP (0.26 ± 0.15 mV) when recorded from pair C. Moreover, the latency of the CMS-CMAP from pair B (5.3 ± 0.4 ms) was significantly shorter than that from pair A (7.1 ± 0.7 ms). The shape of the CMAP measured with CMS (CMS-CMAP) usually differed from that of the CMAP measured with ES (ES-CMAP). Electromyograms were also recorded from upper and lower chest wall surface electrodes. Pair A and pair B were close to the diaphragm ( pair A lower than pair B) pair C was positioned 10 cm above the diaphragm to detect the electromyogram from extradiaphragmatic muscles. A specially designed esophageal catheter with three pairs of electrodes was used, with control of electrode positioning in 10 normal subjects. The results suggest the usefulness of the trapezius muscle electromyography to confirm diagnosis and early physical therapy intervention in neuropathies of the spinal accessory nerve.The purpose of the study was to compare electrical stimulation (ES) and cervical magnetic stimulation (CMS) of the phrenic nerves for the measurement of the diaphragm compound muscle action potential (CMAP) and phrenic nerve conduction time. Surface EMG is a sensitive and painless method for spinal accessory nerve dysfunction evaluation. The median was 12.5 microV after dissection including level IIb, and 8.9 microV after dissection including levels IIb and V (p<0.002). There was a mean decrease of 70% comparing to preoperative values. The patients were grouped according to the type of neck dissection, presence of shoulder pain, impairment during abduction movement and hypotrophy/atrophy of the trapezius muscle.Īction potential had median values of 54.3 microV before surgery and 11.6 microV after it (p<0.001). Nerve integrity was evaluated before and after the surgery by means of surface EMG registering the electric activity of the trapezius muscle during voluntary contraction. Prospective case series of 51 patients submitted to 60 neck dissections followed by physical therapy evaluation of shoulder dysfunction. This study used electromyography to evaluate the injury to the spinal accessory nerve following neck dissection.

The most common complication of neck dissection is shoulder dysfunction due to manipulation of spinal accessory nerve, resulting in trapezius muscle atrophy mainly in procedures involving the posterior neck triangle.

Emg neck