China people's research history on abdominal surgery and anesthesia can be traced back to which period?

Abdominal surgery and anesthesia play a very important role in the field of modern medicine. This operation is very difficult. However, according to the records in ancient Chinese literature, such as the Book of the Later Han Dynasty, as early as the Eastern Han Dynasty and the Three Kingdoms Period (25-265), Hua Tuo, a famous ancient Chinese physician, was able to perform some complicated abdominal operations on patients with anesthesia at that time, so he was called an imperial doctor. It is recorded in the Book of the Later Han Dynasty that when diseases accumulate in the human body and cannot be cured by acupuncture and drugs, the patient must be drunk with narcotic drugs first, and the operation can only be started after the patient loses pain like a drunk. First, the patient's abdominal cavity or back should be cut to remove the tumor. If the disease is in the stomach, it is necessary to cut the stomach, remove the tumor inside, then clean it, sew the cut stomach and sew a plaster. This treatment, which was considered dangerous at that time, can be cured within four or five days and returned to normal within one month. This vivid and detailed description in the Book of Later Han Dynasty tells us that China people could have abdominal and gastrointestinal tumor resection as early as the Three Kingdoms period nearly two thousand years ago, and the wound was completely healed within one month.