1.Pre-operative assessment: location of the patient’s prominence (L5S1, left paracentral prominence) 2.Positioning: which position to take depends on the patient’s condition 3.Needle route: calculate the needle entry point and its direction by means of postural markings 4.Positioning under the C-arm machine after anesthesia: 5.Development: 6.Placement of guide wire, guide rod and catheter: 7.Ring drill reaming: 8.Placement of working trocar: 9.Removal of the nucleus pulposus.