Fig. 2.

Surgical technique. Exposure of the shoulder and arm is essential because muscle twitching can be observed during nerve stimulation (A). Neuromonitoring was performed with a two-channel (one case) or four-channel (four cases) nerve integrity monitor (NIM-2 or -3, Medtronic, Memphis, TN, USA) and a unipolar stimulating probe was used to stimulate the tumor or the nerves before identification and enucleation of the mass (B, C). After enucleation of the tumor, stimulation of the nerve was performed to confirm neural integrity (D).