There is a common deformity of the spine that is familiar to very few people, even though it occurs in up to five percent of the population (that’s one person out of twenty). It is called Spondylolisthesis (Spon-di-lo-lis-thee-sis), which is Greek for “slippage of the spine.” When an affected person is in his or her early teens, a weakness develops in one of the important bony struts that supports the spine. This almost always happens at the lowest vertebra, called L5.
This weakness causes the strut to snap with minimal trauma, such as a mild fall or even a sneeze. Sometimes the child will notice pain, but many times he or she won’t notice anything. Once this strut is broken, the spine can slowly, gradually slip forward. This is because only the disc between the vertebrae is now holding things aligned, and the disk is a soft, rubbery structure that can slowly deform. The slippage can rarely be quite severe: sometimes the spine can slip right off the pelvis! Fortunately, the slippage usually stops after only a little bit, and in any case the slippage stops once a person is fully grown (at about age 18 or so.)
Most people with spondylolisthesis never know they have it until later in life. The typical patient with this condition begins to have pain anywhere from the late 40’s to the late 70’s. This is because the disk holding the spine together eventually wears out, and when it does, the pain starts. The usual pain from spondylolisthesis is a rather severe pain in the base of the spine, which often radiates into the hips or buttocks. It rarely can go down the legs if the nerves that come out of the spine get caught in the slippage.
In most people, the pain comes and goes. It can sometimes be severe, but simple treatments usually work, such as braces, physical therapy, and mild medications. About ten percent of patients develop pain which is chronic, severe, and unremitting. If none of the simple treatments work, we sometimes have to resort to surgical treatment. The operation is called a fusion: the slipped area is stabilized with titanium screws and rods, and further reinforced with a graft of transplanted bone. Most patients who require this surgery have significant relief of their pain.