The possible reasons for keeping low fever after lumbar spine surgery include postoperative absorbed fever and postoperative infection. 1. Post-operative absorbed fever: Keeping a low fever after lumbar spine surgery may be due to the blood vessels reabsorbing the bleeding around the surgery, and the unabsorbed residual blood triggers an immune response, leading to the appearance of fever. 2. Postoperative infection: a low fever that stays low after lumbar spine surgery may be caused by infection. If the patient’s lumbar vertebral space is infected or the wound is infected, the local skin will also appear red, swollen and feverish. After lumbar spine surgery has been low fever may also have other reasons, it is recommended to go to the regular hospital in time, improve the relevant examination, clear the cause of the disease, under the guidance of the doctor to carry out targeted treatment or treatment.