Fig. 4.

A patient with T4 metastases and acute incomplete spinal cord compression underwent unilateral biportal endoscopic surgery. (A) Annotations in the preoperative computed tomography scan revealed 3 incisions were planned for portals insertion. (B) Intraoperative view during T3–4 decompression demonstrating an optimal visualization, which could facilitate the separation surgery. While the endoscope was approaching from the right side, No. 1 is the lateral border of the dural sac. No. 2 is the posterior longitudinal ligament. No. 3 is the T3–4 intervertebral disc space, and No. 4 is the tumor tissue involving the T4 vertebral body. (C) The photograph demonstrating irrigation flow control using the planned incision portals can help with the bleeding control and provide better visualization. (D, E) Axial preoperative and postoperative magnetic resonance imaging images of the T4 level reveal that wide decompression was achieved.