The leg stays numb after doing lumbar spine mini-needle knife may be related to nerve root edema, nerve injury, postoperative scar adhesion, hematoma and so on. 1. When doing small needle knife treatment, it will also cause some tension on the nerves, and the soft tissues around the nerves may produce inflammation and stimulate the lumbar vertebrae, and there may also be jamming on the nerves, resulting in edema of the nerve roots and causing numbness of the legs. 2. It is possible that the process of loosening the nerves when doing the knife treatment has caused damage to the nerves, resulting in numbness of the legs, limited movement and other symptoms. 3. There is a possibility of localized scar adhesion or hematoma after lumbar knife treatment, which may affect and compress the nerves. After the lumbar spine small needle knife after the symptoms of numbness in the legs should go to the hospital in a timely manner to review, clarify the cause, under the guidance of the doctor to actively deal with.