Spinal Canal Stenosis
Spinal Canal Stenosis and its Treatment
Back pain is extremely common in the community, approximately eighty percent of the adult population experiencing a significant episode of low back pain at some time in their lives. In older individuals degeneration of the intervertebral discs and facet joints may combine to result in narrowing of the spinal canal (spinal canal stenosis).
It is however important to remember that not all cases of back and leg pain are the same, even if the symptoms are very similar. Pain felt in the buttock, thigh or leg may be due to a variety of problems in or around the spine and the diagnosis and treatment may vary widely according to the nature of the underlying problem.
Medical assessment attempts to define the anatomical origin of symptoms by obtaining a history (discussing how the pain started, what makes the pain worse or better), performing an examination of the lumbar spine and lower limbs and requesting or reviewing certain radiological investigations.
The investigations that may be requested include plain X-Rays, Computerised Axial Tomography (CAT scanning), Magnetic Resonance Imaging (MRI) and myelography. More information can be provided about these investigations on request.
Spinal canal stenosis results from the compression of nerve roots in the spinal canal and develops as a result of a combination of narrowing of the disc space, bulging of the disc into the spinal canal and degeneration of the facet joints. This occurs due to wear and tear (Figure 2). A degree of spinal canal stenosis is common in elderly individuals and may not be associated with any discomfort.
The only absolute indication for surgical treatment is the development of significant nerve damage, sudden complete paralysis or progressive neurological deterioration (increasing weakness, loss of feeling or control of bladder or bowel function). All other indications are relative and relate to the duration and severity of symptoms.
The presence of degeneration, a bulging disc or spinal canal stenosis on an X-Ray, CAT scan, MRI scan or myelogram is not an indication to undergo surgery unless these features are shown to be the cause of symptoms that are severe enough to warrant surgical treatment.
Wherever possible conservative or non-operative treatment is recommended which may include limited bed rest for acute exacerbations of pain (ie. 2-3 days), medication including analgesics and anti-inflammatories and physical therapy.
If symptoms persist and are disabling despite an adequate conservative programme then surgery may be considered.
The treatment of spinal canal stenosis may include the following:-
- Epidural Injection (See separate page)
- Lumbar Decompression
When the spinal canal is narrow the term spinal stenosis is used. A spinal decompression removes pressure from the nerves by taking away thickened tissue and undercutting the bony structures to enlarge the spinal canal. The operation is done through an incision in the midline of the back and is often referred to as a "laminectomy". Figure 4 illustrates the amount of bone usually removed during a single level procedure of this type.
A decompression operation usually entails a hospital stay of three to five days, after which you will be discharged home, providing adequate support is available. In some cases a period of convalescence in a rehabilitation hospital may be required before returning home.
Up to eighty percent of people gain significant relief from their presenting symptoms, particularly those of buttock and leg discomfort. Surgery of this type will not however reverse the degenerative process that results in these symptoms and although low back pain is also usually improved, patients can expect to experience some low back discomfort following a procedure of this type.
Spinal canal stenosis may also result from one vertebra slipping forward on the one below. This occurs as a result from degeneration of the facet joints. This is referred to as a degenerative spondylolisthesis. In this situation it may be necessary to “stabilise” the spine by performing a fusion in conjunction with the “laminectomy”. This is where one vertebrae is joined to another by placing bone between the two vertebrae. This bone then heals in a way similar to the way fractures heal.
Screws and rods or plates may be used to splint these vertebrae while this healing process takes place. These screws and rods or plates can stay in the body for ever, however in some cases they are removed after a year or two if the are causing irritation of the overlying muscles.
Bone used to fuse the spine may be taken from the back of the pelvis, usually through the same cut in the skin, but in many cases the bone taken from the vertebra during the laminectomy is sufficient.
You will usually get out of bed on the evening of, or the day after your surgery and mobilise progressively with the help of the nursing staff and/or a physiotherapist after that.