Patients with lumbar disc herniation are no stranger to the sensations of pain and numbness. Careful patients will find that pain and numbness are always entwined, sometimes painful and sometimes numb. So, how do pain and numbness arise? What is the relationship between the two? In fact, both pain and numbness are symptoms caused by nerves, which are determined by two specific sensory nerves. Of these two sensory nerves, one nerve fiber is myelinated and relatively thicker; the other nerve fiber is unmyelinated and relatively thinner. When a disc herniates, the herniated part presses on the fine nerve first, and the fine nerve is stimulated to produce pain. After a long period of time, the thick nerve is gradually compressed as well, and then numbness is produced. If the nerve is not treated at this time, when the nerve is severely compressed, the nerve function may not be restored even after surgery. At present, human beings have not yet studied the nerves thoroughly, and the operation of the nerves is not very clear, so the nerves can only be “coaxed” and not touched at will. In the process of nerve repair, pain and numbness follow these two rules: “pain is fast and slow” and “pain is light and heavy”. As the name implies, pain relief is fast and numbness relief is slow. Before the lumbar disc herniation surgery, the patient’s pain is fast and the numbness is slow. After the surgery to release the compression, the fine nerve is not surrounded by myelin sheath, so the pain sensation transmitted by nerve fibers can be relieved very quickly; while the thick nerve is surrounded by myelin sheath, which is equivalent to a layer of membrane protection, and numbness is produced only when the membrane is crushed, so the numbness sensation transmitted by the nerve is relatively slow to recover. As for “light pain and numbness”, as the name implies, the postoperative pain is reduced and the numbness is increased. The reason why “pain is light and numbness is heavy” is that pain and numbness may exist at the same time before surgery, but the pain is more acute and the numbness is often masked. After surgery, pain is removed quickly and numbness is removed slowly, so many patients often feel numbness only after surgery. And this new numbness that appears after surgery may not be due to surgery, but to the regularity of nerve recovery.