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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.3.png)
Figure 3. The entry points of skin (P) and annulus fibrosus (O) calculated by each distance (x, y, and z) were draw together with anatomical bone structure (vertebral body, spinous process, transverse process, facet joint, and iliac crest) (A: intraoperative photography; B: enlarged schematic drawing)