Magnetic resonance imaging is an important test for patients with lumbar disc herniation because it can show structures such as soft tissues and spinal nerves more clearly. Many postoperative patients use MRI to understand postoperative nerve root decompression and to evaluate the effectiveness and prognosis of the surgery. The newer spinal internal fixations used today are mostly made of pure titanium or titanium alloys, which do not interact with magnetic fields, are not attracted to magnetic fields, and do not move in magnetic fields. As a result, patients with internal fixation made of this material have no postoperative interference with MRI examinations of the surgical area or other parts of the body, which is valuable for patients with spinal disease who require internal spinal fixation. However, in patients with older internal fixations made of materials such as stainless steel, the material may move in the strong magnetic field and damage adjacent large blood vessels and important tissues, resulting in unexpected and serious consequences, which is generally a relative contraindication to MRI. Patients must fully communicate with their physicians beforehand to determine the most appropriate examination method.