Lumbar spinal stenosis, a type of disease in which the diameter of the spinal canal shortens, compressing the dural sac, spinal cord or nerve roots, resulting in corresponding neurological dysfunction, is commonly seen in the elderly. Previously, open surgery was a very traumatic procedure with slow postoperative recovery. Lumbar spinal stenosis has been treated by unilateral decompression with foraminoscopy, which has opened a new era in the treatment of lumbar spinal stenosis! Lumbar spinal stenosis is insidious in its onset and slow in its course, and is commonly seen in elderly patients. The causes of stenosis are very complex, and depending on the clinical stenosis site, the typical symptoms of patients may include: long-term lumbosacral pain, leg pain, progressive weakness and numbness of both lower limbs, intermittent claudication, and difficulty walking. The numbness can gradually progress upward from the feet to the calves, thighs and lumbosacral region, and the abdomen can feel like a girdle. Lumbar spinal stenosis is insidious in its onset and slow in its course, and is common in elderly patients. The causes of stenosis are complex, and depending on the clinical stenosis site, the typical symptoms of patients may include: long-term lumbosacral pain, bilateral lower extremity radiating pain, progressive weakness, numbness, intermittent claudication, and difficulty walking. Among them, numbness can gradually progress upward from the foot to the calf, thigh and lumbosacral region, with a girdling sensation in the abdomen and, in severe cases, abnormal urination and defecation and paraplegia. In the past, open surgery for lumbar spinal stenosis severely stripped the muscles of the patient’s low back, often leaving chronic low back pain after surgery and slow recovery after surgery. With the development of minimally invasive spine technology, unilateral access bilateral decompression under MED (discoscopy) for lumbar spinal stenosis has been gradually realized, and unilateral access bilateral decompression under expandable channel can be used for unstable lumbar spinal stenosis. However, elderly patients with lumbar spinal stenosis are often combined with multiple medical diseases and have difficulty tolerating general anesthesia. Therefore, the use of foraminoscopic techniques for the treatment of stable lumbar spinal stenosis has been gradually explored in recent years. According to Chen Bin, director of minimally invasive spine surgery at the Affiliated Hospital of Chengde Medical College, the key to expanding the indications for intervertebral foraminoscopy is the selection of the surgical approach. A unique surgical approach can expand the microscopic field of view. Previous intervertebral foraminoscopic techniques had limited exposure of structures in the spinal canal, revealing only part of the nerve roots and dural sac. The “foraminoscopic perineural decompression and release” technique uses a special approach that allows for the microscopic exposure of the inferior nerve roots, the exiting nerve roots, the dural sac, the posterior longitudinal ligament, the protruding nucleus pulposus, the fibrous ring, the ligamentum flavum, and even the contralateral nerve roots. Due to the special access of this technique, operations such as foraminal enlargement and shaping, lateral saphenous fossa enlargement and shaping, and ventral decompression of the dural sac can be performed to complete the enlargement and decompression of the spinal canal in spinal stenosis. Typical case: The patient, a 60-year-old female, was admitted to the hospital with lumbar pain with bilateral lower extremity discharge pain for 10 years, aggravated for 2 years. The patient had bilateral hip, posterior lateral thigh, lateral calf to dorsalis pedis radiating pain, with the left side being more severe than the right. MRI showed a herniated L4-5 disc with compression of the dural sac, thickening of the ligamentum flavum, and narrowing of the corresponding intervertebral foramen and lateral saphenous fossa. After discussion of the case within the department, the patient underwent foraminoscopic perineural decompression. The herniated nucleus pulposus was removed, the lateral saphenous fossa was enlarged, and ventral decompression of the contralateral nerve root was gradually achieved via the ventral side of the dural sac. After the surgery, the patient immediately felt the pain and numbness of both lower limbs disappeared. The straight leg raise test was negative after lying in a flat position. Two hours after surgery, the patient was lowered to the floor under the protection of a lumbar brace. The treatment of stable lumbar spinal stenosis by unilateral decompression with intervertebral foraminoscopy has obvious advantages. This procedure has the advantages of low surgical trauma, low intraoperative bleeding, local anesthesia, low cost, rapid postoperative recovery, and wide range of indications. With the advent of an aging society, the number of elderly patients with lumbar spinal stenosis will continue to increase. The application of this technique makes the treatment of the majority of lumbar spinal stenosis patients simple and effective, gets rid of back and leg discomfort for more elderly patients, and improves the quality of life of the elderly!