Huamei plastic surgery experts said: First of all, bone grinding is an operation under the premise of preparation, which is different from some operations that accidentally lead to fractures. Fracture is generally caused by pulling or damaging the muscles, sarcolemma and periosteum around the bone without preparation. But grinding the bone will not damage these tissues, so the pain will not be so great. Secondly, bones don't feel nerves, so they don't feel pain. Guan Yu's bone scraping therapy is so painful because Bian Que is actually scraping soft tissue for him during the operation, which is different from bone grinding operation. Third, Guan Yu didn't use anesthesia when scraping the bone. Coupled with the poor surgical conditions and long operation time, it certainly made him feel very painful. Bone grinding surgery is generally performed under anesthesia. With the improvement of medical equipment and technology, the duration of surgery is also shortened. Therefore, continuous sculpture surgery is an operation to remove a part of prominent cheekbones or mandibles with a square chin, which is less painful than other operations.