What is it?

This condition is characterised by a narrowing of the spinal canal that carries the nerve roots. This leads to compression and ultimately dysfunction of these nerve roots. The process usually starts off in the disc with a decrease in the height of the disc as well as the weight carrying ability of the disc. The settling of the disc leads to compression of the nerve roots. The compressive elements are a combination of a thickening of the normal ligament of the spine, the ligamentum flavum, and the enlarging of the facet joints (see the section on anatomy).
The facet joints enlarge in response to their greater weight carrying responsibility as the disc becomes damaged. There is usually an amount of slippage of the vertebrae on top of each other and the spine can be bent from side to side in an S-shape (scoliosis) or have an abnormal angle of bending forwards(kyphosis) or backwards (lordosis). This is part of the normal aging process and is called aquired spinal stenosis. Another term is sponylosis or spinal osteoarthritis.

Another form is that of an inborn abnormality, which predisposes people to this condition. The people who are are born with congenital spinal stenosis have a very small spinal canal. This is because the pedicles(see the section on anatomy) are shorter that normal and do not allow for sufficient space in the spinal canal. Spinal stenosis leads to a syndrome of nerve compression that is usually a very slow and progressive disease. It does not allow for spontaneous remission sometimes seen in intevertebral disc disease but rather has periods of slow deterioration interspersed with periods of quick deterioration in a permanently progressive condition.

What are the symptoms?
(local back pain, referred pain, spinal claudication, radicular symptoms)
   
The facet joints and discs lead to local back pain and referred pain to the thoracic spine (chest) and down to the upper part of the legs. The nerve roots that are compressed lead to pains in the legs called spinal or neurogenic claudication. This is a pain that typically occurs when walking or standing and becomes better when sitting down. Spinal stenosis is frequently part of a crooked spine (scoliosis) and the degenerative discs combine with the scoliosis to compress nerve roots leaving the spine to give radicular symptoms - see the chapter on lumbar disc herniation.

How is it diagnosed?

A clinical examination by your doctor or therapist will allow for a reasonable suspicion but the only definite way is by doing a magnetic resonance (MR) scan (see the section on tests).  Sometimes because of technical factors a CT scan is performed (see the section on tests). This is usually when a MR scan cannot be performed due to the unavailability of a MR scanner, when there are contra indications to doing a scan (see the section on tests) or there are technical factors like the presence of metal fusion apparatus in the spine that make a MR scan unreliable.  See the section on tests for the terminology that you will find on your MR scan report and what it means in plain English.

Other tests that might be used are discograms (see the section on tests) and nerve blocks (see the section on tests). Sometimes EMG’ s are also used (see the section on tests).

What is the treatment?

There are always four options:

No treatment - This is acceptable if there are no serious nerve compression - therefore in the absence of spinal claudication or radicular symptoms. There are always people who choose this option for a variety of personal reasons. This is also the option that is chosen in people who are have serious medical conditions that does not allow them to have an anaesthetic. It is rare for this condition to become better without surgery and it usually follows a progressive course with symptoms increasing.

Treatment that does not require intervention - Courses of painkillers and anti-inflammatory drugs can be combined with treatment from therapists to control symptoms. Appropriate in patients with limited spinal clauducation and radicular symptoms. Both this and the previous strategy is equally acceptable.

Limited intervention - This include procedures like sacral blocks, radiofrequency rhizotomies and disc nucleoplasties. These treatments are highly effective, have very few side effects or complications and are performed as day procedures. They have a very definite place in the management of spinal stenosis and can buy years in the management of this condition.

Currently only some spinal surgeons are trained in these techniques and try and consult someone that has training in these, and performs these on a regular basis to see whether you qualify for these treatments and whether they are suitable for your condition.

Intervention(surgery) -  the indications for surgery are:
1.) Failed conservative management
2.) Pain that does not respond to any other treatment modality and is sufficiently severe to limit your daily activities and quality of life. This includes local lower back pain, referred pain and radicular pain.
3.) Muscle weakness due to nerve compression (radicular weakness)
4.) Cauda equina syndrome and conus medullaris syndrome (see chapter 4).