Fig. 3

Male patient of 42 years with L4/5 disc herniation and calcification underwent the procedure of PTES. a Sagittal, b axial MR images, and c CT scan showed calcification in L4/5 disc herniation. During the procedure of PTES, d posteoanterior and e lateral C-arm image confirmed that a 7.5-mm working cannula was advanced directly to the protruding fragment. A 3.5-mm small reamer was used to grind off g calcified tissue under f view through the endoscope, which was confirmed on h CT scan after surgery