Lumbar instability is predominant in elderly people over 50 years of age. Patients may show sudden restriction of lumbar activities, inability to move, and difficulty even turning over. Some patients do not have obvious diseases, but often feel soreness and pain in the lumbar back, which is relieved when resting, and their forward flexion or dorsal extension activities are limited to varying degrees. There are also patients with lumbar instability complicated by disc herniation, thickening of the ligamentum flavum and alteration of the physiological curvature, resulting in spinal stenosis of the corresponding segment and symptoms such as low back pain and intermittent claudication. There are also patients with moderate scoliosis and nerve irritation causing reflex pain in the lower extremities due to complications. Generally, the physician’s physical examination produces severe lower back pain by giving a vertebral body a mild stimulus such as pressure, touch, or twisting. In these patients, if the pain is reduced or disappears after proper braking with a lumbar brace or brace, it strongly suggests lumbar instability. Patients need to make lumbar spine X-ray (lumbar spine frontal and lateral, power position film) to diagnose.