Spinal stenosis

What is spinal stenosis?

A constriction of the vertebral canal is a condition in which the space for the nerves in the vertebral canal gets smaller, especially where the nerve roots exit the vertebral canal. A protruding vertebral disc can sometimes also exacerbate the constriction (see slipped disc).

In principle, a narrowing may be anywhere in the vertebral column but it is found most commonly in the neck (cervical stenosis) or in the lower back (lumbar stenosis). This condition may be due to a developmental deviation before birth, injury to the vertebral column or ageing/'wear and tear'. There are often no symptoms initially but this can change with age. The condition is seen most commonly in people aged over fifty.

What are the complaints associated with a spinal stenosis?

The condition is linked to the tripling of the risk of pain in the lower back by comparison with other people. ¹⁷⁶

However, it need not necessarily result in complaints. The complaints manifest themselves only when the narrowing exerts pressure on the spinal cord and nerves. Lumbar stenosis results in pain in both legs that often begins or is exacerbated during walking. The symptoms therefore resemble those associated with vascular constriction in the legs (see intermittent claudication). The pain caused by walking in lumbar stenosis arises because the space in the spinal canal is most restricted, and pressure on the spinal cord is therefore highest, when a person is in an upright position. There will sometimes be numbness and/or a loss of strength. When the person is at rest, and particularly in a bent posture, squatting or sitting, the pain subsides quite quickly. People with a spinal stenosis have no difficulty cycling.

People with intellectual disabilities sometimes find it impossible to communicate the pain. They may not want to walk or the people around them may notice only a change in behaviour.

How common is spinal stenosis in the general population?

The prevalence of lumbar stenosis was investigated in the Framingham study: a relative narrowing of the spinal canal (diameter ≤ 12 mm) was found on CT scan in 23.6% and an absolute narrowing (diameter ≤ 10 mm) was seen in 8.4% of the sample. The prevalence rates for people aged between 60 and 69 years were 47.2% and 19.4% respectively. ¹⁷⁶

The prevalence of spinal stenosis in the neck (cervical stenosis) was assessed in a post mortem study of 469 adults: 4.9% had cervical stenosis. The prevalence rate was 9% in people over the age of 70. ¹⁷⁷

A US study of 262 young adult/adolescent football players found a prevalence of 7.6% for cervical stenosis. ¹⁷⁸

A major Rotterdam study found that 13% of all people referred by a GP for an MRI for lower back pain had spinal stenosis. ⁵⁰¹

How common is spinal stenosis in people with intellectual disabilities?

There have been no studies of lumbar or cervical stenosis in people with intellectual disabilities. 

However, one study looked at 48 people affected by functional decline. It was initially assumed that the decline was associated with dementia or the aetiological diagnosis. However, it was found that 16% had severe compression of the spinal cord or myelopathy (spinal cord disease) that explained the symptoms. Mild vertebral anomalies were found in 20% of the group studied; moderate to severe degenerative anomalies in the vertebral canal were seen in 48%.

The authors concluded that vertebral conditions in people with intellectual disabilities are often not recognised, that complaints are not expressed or that they are expressed in other ways, and that symptoms are also not interpreted correctly. Furthermore, people with intellectual disabilities may be at increased risk of spinal stenosis because the relevant risk factors (osteoporosis, possibly associated with anti-epileptics, fractures and 'wear and tear') are more common in these people. In addition, people with cerebral palsy are more likely to have cervical stenosis. ⁵⁰²

In addition to the instability of the first two cervical vertebrae (atlanto-occipital instability), people with Down syndrome often have spinal stenosis attributable to a small cervical vertebra (C1). ¹⁷⁹