Lumbar Listhesis is a condition where the spine becomes unstable caused by abnormal vertebrae movement, in this case, sometimes vertebrae slip out of place and onto the lower vertebra putting pressure on the nerves. This could cause lower back or leg pain. Spondylolisthesis is a spinal condition that causes lower back pain. It occurs when one of your vertebrae, the bones of your spine, slips out of place onto the vertebra below it. Most of the time, nonsurgical treatment can relieve your symptoms.