Phantom limb pain is the phenomenon of subjective feeling that the amputated limb still exists and has pain of different degrees and nature. Many patients end up amputating their limbs for various reasons, but, subconsciously, they always feel that the amputated limb still exists and has unbearable pain, the cause of which is still unknown. The following is to explain to you. 1, brain function changes after amputation cortical function reorganization and phantom limb pain are closely related. The so-called cortical reorganization is that when the sensory cortex of a part of the brain is damaged, the adjacent sensory cortex produces functional reorganization to maximize the function of the damaged cortex. Katz et al. have investigated the correlation between phantom limb pain and pain experienced before surgery and found that 42% of patients had pain of similar nature and location as before amputation, indicating that phantom limb pain is related to pain memory function in the brain. Subarachnoid anesthesia can induce or relieve phantom limb pain, while phantom limb pain can disappear after spinal cord dorsal root surgery, and Curt A reported that patients with spinal cord loss can cause phantom limb pain. These phenomena suggest that phantom limb pain may be closely related to the alteration of spinal cord function. 4, peripheral nerve function changes The injection of local anesthetic at the severed end of the amputated limb, especially at the site of neuroma formation at the severed end of the nerve, can relieve or cure phantom limb pain, so it is certain that phantom limb pain is related to the severed peripheral nerve function changes. 5. Psychological factors Phantom limb pain is also related to the psychological state of the patient. Patients who have a positive and optimistic attitude towards limb loss are less likely to suffer from phantom limb pain.