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![Posterolateral percutaneous endoscopic discectomy with free-running electromyography monitoring under general anesthesia](https://image.oaes.cc/482e904c-a2df-4aa9-a5f4-95168f835847/2200.fig.1.png)
Figure 1. Intraoperative view of free-running electromyography (EMG) monitoring. (A)The needle electrodes are located on bilateral gluteus medius, hamstrings, quadriceps, tibialis anterior, and gastrocnemius; (B) exact waves of EMG from gluteus medius (upper) and tibialis anterior muscle (lower) are shown. Note that the waves reach the level of warning alarm (white arrows)