Piriformis syndrome does not cause back pain, it can cause symptoms of sciatica in the lower extremities. Piriformis syndrome is caused by damage to the piriformis muscle itself, a tumor in or around the piriformis muscle that causes pressure on the sciatic nerve, resulting in symptoms of sciatica that radiate from the buttocks all the way down the back of the thighs to the calves, soles of the feet, and dorsum of the feet with numbness, painful sensations, or weakness. Piriformis syndrome is often confused with lumbar disc herniation, which can also lead to sciatica symptoms, but is accompanied by significant lower back pain, especially when sitting for long periods of time or when the lower back gets cold. Piriformis syndrome, on the other hand, can cause pain in the buttocks and does not cause back pain, so piriformis syndrome does not clinically cause back pain. If sciatica is accompanied by low back pain, consider whether it is caused by lumbar disc herniation.