Exostoses of bone tissue or protrusions of disk tissue can lead to constrictions at the nerve exits of the vertebral joints (foraminal stenoses) or in the spinal canal (spinal stenoses). This results in the irritation of the nerve roots as well as feelings of numbness and instability while walking.
A foraminal stenosis can be caused by facet arthrosis. This phenomenon of wear and tear results in an increased development of wild bone mass, which may constrict the nerve exit from behind. Yet disk tissue invading the nerve exit or exostoses of the vertebral bodies can pressure it also from the front. This can happen, for example, following old disk prolapses or in the wake of degenerative changes in the disks (osteochondrosis). All this results in the irritation of the relevant nerve root and radiates out into the back and legs, including feelings of "furriness", pricks and needles, an antsy kind of itching and the loss of reflexes. In spinal stenoses, there is a difference between primary and secondary forms. Primary means that a person has already been born with a constricted spinal canal.
Yet many people above the age of 60 suffer from a secondary stenosis caused by wear and tear, meaning an acquired constriction of the spinal canal. The constriction may have different causes: damaged spinal disks which protrude, and exostoses of bone tissue at the intervertebral joints (spondylophytes), but also a thickening of the ligamentum flavum, the ligament, which holds both vertebral bodies together, thus adding stability to the spine. Following disk surgery, too, the development of spinal stenoses 10 to 15 years later is not an infrequent phenomenon. Patients usually notice these due to diffuse pain in the legs or bottom, usually only when walking, or sometimes when standing. Many describe a feeling of insecurity while walking, as if walking on the planks of a ship, and also experience back pain, rapid exhaustion while walking and sometimes even feelings of numbness in the legs or buttocks. Unfortunately, spinal stenoses in people over 60 are the most common reason for unnecessary spinal surgery.