Scoliosis developed in adulthood can be “secondary” to other spinal conditions that affect the vertebrae. Other conditions such as degeneration, osteoporosis (loss of bone mass), or osteomalacia (softening of the bones) can cause scoliosis. Scoliosis can also appear following spinal surgery for other conditions. The surgery may cause an imbalance in the spine that leads to scoliosis. Most of these secondary causes of scoliosis are considered degenerative adult scoliosis.
Degenerative adult scoliosis usually begins as low back pain. While there may also be a deformity that causes the back to look abnormal, usually pain is what motivates patients to seek treatment. The pain is probably not coming from the curve, but rather from the degeneration occurring in the spine.
A combination of the degeneration of the spine and scoliosis deformity may cause pressure on nerves and possibly even the spinal cord. This can lead to weakness, numbness, tingling and pain in the lower extremities. In severe cases, pressure on the spinal cord may cause loss of coordination in the muscles of the legs, making it difficult to walk normally.
The degeneration and the scoliosis may have caused a condition called spinal stenosis, a narrowing of the spinal canal. Spinal stenosis results from spinal degeneration that has led to the growth of bone spurs. Eventually the spurs take up space in the spinal canal, causing it to become smaller. This leads to bone pressing on the spinal cord and its nerve roots. The lack of space lessens the nerves’ supply of blood and oxygen, which can lead to numbness and pain in both legs.