Patients suffering from lumbar disc herniation often feel back pain, lower extremity pain and numbness. Doctors often perform tests such as lumbar spine x-rays, lumbar spine CT or lumbar spine MRI. common x-rays of patients with lumbar disc herniation show lesions lumbar space narrowing, and lumbar spine CT and MRI show lumbar discs protruding into the spinal canal compressing the dural sac and/or nerve roots. Yesterday I performed surgery on a patient with a lumbar disc herniation. This patient had lumbar pain with right lower extremity pain and numbness in the dorsum and plantar aspect of the foot after sudden exertion of the lumbar region. On physical examination, there was obvious pressure pain on the right side of L5/S1 with radiating pain, straight leg elevation of the right lower limb was only 20°, and there was obvious loss of sensation in the lateral calf and dorsum of the foot, and weakness of the dorsal foot extension muscles. Only mild bulging of the L5/S1 intervertebral disc was seen in the magnetic resonance cross-sectional view. The patient was seen at a hospital, where the physician suspected lumbar disc herniation but did not make a clear diagnosis, and was given mannitol plus dexamethasone for dehydration and intramuscular neurotrophic injections. The patient’s symptoms did not improve significantly after one week of treatment. The patient went to another hospital, and the doctor said that there was no obvious disc protrusion on the MRI, so it was not lumbar disc herniation, and the diagnosis was sciatica. After nearly a month of acupuncture, physiotherapy and herbal treatment, the patient’s symptoms still did not ease. During November, the patient came to my clinic, and after examination I concluded that the patient had a high likelihood of developing lumbar disc herniation. After careful reading of the MRI, I found that the patient had an occupying lesion in the right nerve root canal and the nerve root was clearly compressed. From the MRI sagittal view, a substance with the same signal as the detached disc was clearly visible in the sagittal view of the right radicular canal compressing the nerve root. I then positively diagnosed a very lateral type lumbar disc herniation and told the patient that surgery was needed. During surgery, when the entrance to the nerve root canal was revealed, the nerve root was found to be significantly thickened with minimal nerve root movement. After enlargement of the nerve root canal, a large piece of detached disc tissue was found ventral to the nerve root. After removal of the detached disc, the nerve root was significantly relaxed. At the checkup this morning, the patient said that the pain that had been tormenting him for more than a month had finally disappeared. Extremely lateral type disc herniation accounts for about 1% to 11.7% of the total number of patients with lumbar disc herniation, with an average of about 10%. Normal CT and MRI scans are thicker and often miss the intervertebral foramina, leading to clinical underdiagnosis. In contrast, 90% of patients with extreme posterolateral disc herniation are poorly treated conservatively and require surgery. Therefore, accurate diagnosis of extreme posterolateral disc herniation is very important and requires a certain degree of clinical experience and a high level of film reading ability.