Patients often ask why others have such good results after surgery with no discomfort at all, while I would have numbness in my legs, or slight pain? The following is a brief analysis of the principles of pain and numbness, which I hope will be helpful in understanding this issue and in choosing the timing of surgery for patients. The International Association for the Study of Pain (IASP) defines pain as “an unpleasant sensory and emotional experience that is accompanied by tissue damage or potential tissue damage.” That is, pain implies tissue damage or potential damage, and as the damaged tissue is repaired, the pain gradually decreases and disappears when the tissue is completely healed, a predictable pain called normal pain. However, when some traumatic injuries or diseases involve the nervous system, such as peripheral nerves, spinal cord or certain parts of the brain, even after such damage is healed, there is still persistent pain that lasts for months, years or even a lifetime, and the abnormal pain caused by such damage is called neuropathic pain, which is caused by pathological changes in the nervous system. For example, nerve compression, nerve trauma, postherpetic pain, diabetic neuropathy, etc. Spinal diseases including cervical spondylosis, lumbar synostosis and spinal stenosis cause pain mostly due to inflammatory edema (increased pain-causing substances) caused by herniated discs compressing or stimulating nerve roots or sinus nerves. Therefore, after rest, hormones, surgery to release compression and other treatments, the inflammatory edema subsides and pain can be reduced or disappeared, but about 7% of low back pain eventually manifests as neuropathic pain, which can exist for several years or even for a lifetime. Treatment is not effective. Other patients may say that the pain is gone, but the numbness is gone, or in some cases, the numbness is present early. Compared to pain, numbness is a little more difficult to treat, or even no treatment. Long ago there is a common saying: treat pain but not numbness. This is because numbness is mostly due to protrusion and compression for a long time, or a short period of time, but protrusion and compression is very heavy, resulting in damage to some of the nerves have already occurred, damage to the nerves there is no clear and effective treatment. Therefore, although pain and numbness due to cervical spondylosis and lumbar spondylosis are not fatal diseases, if there is severe compression, the doctor will recommend surgery or early surgery. The purpose of surgery is to relieve the compression early and create conditions for nerve recovery to avoid neuropathic pain or intractable numbness that may result from the compression over time. The following diagram shows the ischemia and nerve degeneration that results from nerve or spinal cord compression, which is helpful to understand.