Scoliosis refers to a deformity largely in the coronal plane. That is the spine looks curved rather than straight as you may look at someone from behind. There are often deformities in the other planes such as rotation and translation and loss of normal lordosis as well.
The degenerate scoliosis occurs in later life and is essentially a complication of having multilevel disc and facet joint arthritis or degenerative spondylosis. It is not clear why some people develop a scoliotic curve and others degenerate without this deformity, but the more severe the degenerate process, the more likely the scoliosis.
The asymmetric collapse of a disc is a very common finding and this can lead to foraminal stenosis on the concave side of the curve. It is often the nerve compression that leads to the presentation with leg pains similar to spinal stenosis syndrome. This pain can be difficult to control with simple measures as the deformities are often fixed. Analgesic medication can be trialled but side effects are common in the elderly and careful dosing is required. Nerve root or epidural injection can sometimes be helpful.
Surgery to decompress and stabilise or correct the deformity is complex and again because of the age of the typical patient, the risk of complication is much higher, Sometimes simple decompression can be undertaken but care must be taken not to further destabilise the spine. Oftentimes some sort of stabilisation must be performed to control or correct the deformity if surgery is to be successful beyond the short term.
The Lateral Interbody techniques including OLIF are showing some promise for this group of patients because they are able to provide a powerful correction and utilises a minimally disruptive approach and therefore is lower risk than traditional open posterior techniques. Risks of anaesthesia are still present in this age group and the decision for surgery must be made on an individual case by case basis, weighing up the benefit to risk ratio in consultation with the patient.