Case: The patient was a 62-year-old woman presenting with low-back pain of 3 years' duration and numbness in the right leg. Diagnosis: She was diagnosed with lumbar spinal stenosis based on combined magnetic resonance imaging, physical examination, and symptoms. Interventions: Treatment with computed tomography-guided percutaneous release of the ligamentum flavum was delivered. Outcomes: Relief of symptoms immediately after treatment and complete resolution of symptoms after 1 month were achieved. At follow-up, there was no recurrence of symptoms after 2, 4, 6, and 12 months. Conclusion: Lumbar ligamentum flavum hypertrophy is an important cause of degenerative lumbar spinal stenosis. The hypertrophic ligamentum flavum can directly compress the spinal canal, squeeze the cauda equina, and simultaneously lead to a reduction in the anteroposterior diameter of the intervertebral foramen, which compresses the nerve roots and causes numbness and other symptoms of lower extremities. In clinical practice, doctors should combine imaging findings with patient symptoms for diagnosis and an individualized treatment plan for each patient with lumbar spinal stenosis, and conduct gradual stepwise treatment using conservative minimally invasive surgery to prevent excessive surgery.