Fig. 3

Schematic diagram of procedures of removing the calcified herniation. a Insert an 18-gauge puncture needle to the posterior 1/3 of the intervertebral space. b Press-down Enlargement of Foramen: through an 8.8-mm diameter cannula, use a 7.5 mm trephine to enlarge the foramen and simultaneously remove the calcified herniation. Compared with removing the uncalcified herniation, the trephine was pressed down further and deepened to remove the calcification directly. c Most of the calcification was removed. Rest of the calcification was removed using trephine, electric drill or ultrasonic bone scalpel under endoscopic view