Spondylolisthesis
The spondylolisthesis is a very common type of spinal instability. There are different causes of spondylolisthesis. In later life it arises when the vertebral joints have been weakened by wear and tear (especially the spine). This leads to relaxations that lead to a slippage of the vertebrae, in the most stressed segment (between the fourth and fifth lumbar vertebrae).
The organism tries to compensate the loss of stability through bony attachment, like a leaning tower that is to be saved by pillars and cement from overturning. This leads to a "thickening" of the vertebral joints, the so-called spondylarthrosis. Spondylarthrosis and spondylolisthesis often lead to a narrowing of the spinal canal, called spinal stenosis. This can be seen as "collateral damage" because the body does not stop at my nerves in its pursuit for stability.
For young people the most common cause of spondylolisthesis is spondylolysis, i.e. a bony weakness of certain vertebral arch shares. This usually does not lead to a narrowing of the spinal canal.
Leading symptoms are severe back pain that may radiate to the thighs. These pains are very strong in the morning when the back muscles are relaxed and thus the instability particularly pronounced.
The narrowing of the spinal canal causes mainly "nerve pain" that can spread to the feet and grow under stress, so that the patient must often take breaks when walking.
Furthermore, numbness and paralysis in legs may be present. In particularly severe cases a bladder dysfunction may occur.
Treatment measures are conservative, minimally invasive or surgical.
If back pain is in the foreground and the spondylolisthesis is rather low in its extent, a conservative therapy - especially for younger people -to build the back muscles for outer stabilization can be successful.
With progressive spondylolisthesis as a result of wear and tear, wearing a corset can also relieve the back pain temporarily. Sometimes a facet denervation i.e. a degradation of the pain-conducting nerve fibers also helps.
For severe pain and / or neurological deficits particularly in relation to a narrowing of the spinal canal, it must be extended and the spine stabilized. The vortices have to be linked together rigidly (reinforced) so that the painful rubbing movements are no longer possible. There are several 
surgical techniques to do so.
