Sacral anesthesia refers to the injection of local anesthetic into the sacral lumen through the sacral cleft to block the sacral nerves, which is a kind of epidural anesthesia, and is suitable for rectal, anal and perineal surgeries. When performing sacral puncture, the patient can take the side-lying position or prone position, when the side-lying position, the patient’s waist and back arched backward, the two knees to the abdomen close together, pretending to be a “big shrimp” shape. In the prone position, the patient is placed on a small pillow at the hip, the legs are slightly separated, the toes are tilted inward, and the heels are externally rotated to relax the buttock muscles. Before puncture, the tip of the coccyx is touched, and then along the midline about 3-4 centimeters toward the head, a V-shaped or U-shaped depression can be felt, and on each side of it there is a bean-sized bony elevation of the sacral angle, which is the sacral cleft hole. A dermatome is made in the center of the sacral cleft, and the needle is passed vertically through the skin and the sacrococcygeal ligament that covers the sacral cleft. When the ligament is penetrated, there is a feeling of resistance suddenly disappearing, at this time, the needle stem and the skin at an angle of 30 degrees into the direction of the needle, you can enter the sacral lumen. If the angle is too large, the tip of the needle can easily touch the anterior wall of the sacral canal; if the angle is too small, the tip of the needle can touch the posterior wall of the sacral canal. Whenever bone is encountered, the angle should be adjusted so that it is in the same direction as the longitudinal axis of the sacral canal and the needle can enter smoothly. After the needle is inserted into the lumen of the sacral canal, the depth of advancement of about 2 centimeters is sufficient. The bony landmark of sacral 2 is the line of posterior superior iliac spine, and the puncture needle should not enter too deep and cross this line, otherwise there is a danger of piercing into the subarachnoid space. When sacral anesthesia is performed clinically, 1.5% lidocaine or 0.5% bupivacaine can be used, both of which can be added to epinephrine in appropriate amounts. The amount of drug used in adults is usually 20 ml, and its anesthesia time is 1.5-2 hours and 4-6 hours, respectively. A split injection method can be used, where 5 ml of the experimental dose is injected first, observed for 5 minutes, and then the remaining 15 ml is injected if there is no adverse reaction.