What Is Spinal Stenosis?
Spinal stenosis is a term used to describe a narrowing of the spinal canal. This narrowing may occur throughout the spinal canal, but mainly occurs within the more mobile areas of the spine, either within the lumbar spine (lower back) or the cervical spine (neck).
The narrowing may cause symptoms due pressure on the spinal cord, see Myelopathy, or pressure on the nerve roots, which is often seen within the lumbar spinal canal.
Stenosis within the lumbar spine often occurs as a result of degenerative changes within the spine, known as spondylosis. These are part of the natural aging process within the spine, but in some people the degenerative changes within the facet joints at the back of the spine and the intervertebral discs at the front cause narrowing of the spinal canal, with subsequent pressure on the spinal nerves.
If this occurs in the main central spinal canal it is termed central stenosis and if the narrowing affects the smaller side tunnels with the spine which is called foraminal stenosis or ‘lateral recess stenosis’. Patients may experience leg pain, in one or both legs, as well as a feeling of heaviness, weakness or numbness within the legs.
Typically these symptoms occur, or are made worse by walking, with patients feeling increased pain within the legs along with numbness, weakness and feelings of unsteadiness. The tunnels in the spine are smaller when you are standing, but larger on sitting with the spine bent. The nerves within the spine are both compressed by the constriction and also their blood supply is temporarily reduced by the compression. Consequently symptoms may be relived by resting, leaning forward or sitting down, which then allows patients to resume walking. If symptoms deteriorate patients find that they can walk a shorter distance before the pain stops them and they are forced to rest.
I also have back pain, is the treatment the same?
The leg symptoms may be associated with back pain. It is important to decide which is the major symptom, back pain or leg pain, as the treatments may be different depending on the predominant problem.
What else could be causing my leg pain?
Other causes of the leg symptoms may be pain from the hip or from narrowing of the arteries within the legs. Narrowing of the leg arteries may cause pain on walking termed, vascular claudication. These symptoms may be very similar to the symptoms of spinal stenosis (spinal claudication), and tests on the blood supply to the legs may be needed to determine which is causing the symptoms.
Other causes include diabetes or vitamin B12 deficiency, both of which can be diagnosed with simple blood tests.
Will I get better without treatment?
The course of the problem has some uncertainty, but a general rule can by applied that 20% will improve with time, 60% will stay the same and 20% will worsen with time.
What treatments are available?
Treatment options fall broadly into three categories.
Improving spinal mobility, strength and overall fitness may improve symptoms to a satisfactory level. Static cycling is extremely good exercise. Patients generally do not experience as much pain as when they walk because the spine is in the flexed or bent position, thus increasing the space available for the nerves. It is important to note that the presence of pain does not indicate that damage is being done to the spine. Simple pain control, using over the counter medication such as Paracetamol or anti inflammmatories, such as Ibuprofen, are extremely helpful. Nerve pain modifying drugs such as Amitriptyline, or Gabapentin may also be useful in controlling the pain.
Spinal injections are extremely useful in some patients to help to relieve the leg or back pain symptoms associated with spinal stenosis. They may also be useful to assist in localising the area within the spine, which is causing the symptoms prior to planning surgery. They have the advantage of being performed under local anaesthetic and although there are potential risks and side effects, these are extremely rare. They can also be repeated if required.
Epidurals are an injection into the spinal canal that will treat the whole area of the lumbar spine. They seem to be more helpful for leg pain but may be of some benefit for back pain.
Nerve root blocks, periradicular injections, root canal injections, or transforaminal epidurals are some of the names given to injections around a nerve. They can be very helpful for leg pain, particularly symptoms in just one leg. They are also helpful with localising the area of the spine, which is causing the problem, prior to planning surgery.
Often by blocking the nerve pain with anaesthetic the symptoms will improve permanently or give a period of prolonged pain relief. It is estimated that 60% of patients will have significant relief of symptoms.
If symptoms remain unacceptable despite all the simpler measures or if symptoms get worse then surgery may be considered. This will also depend upon your general health and fitness.
The pressure can be relieved directly by removing the bone and soft tissue, which is pressing on the nerves, this is known as a spinal decompression. See Lumbar Decompression.
Alternatively the pressure can be relieved by indirect means where by a device is placed between the spinous processes at the back of the spine thus creating more space for the nerves. The advantage of this second type of procedure is that it is less invasive, however it may not be suitable for every patient. The ability to sit for about half an hour without leg symptoms is one of the factors that might indicate that this is a suitable procedure for an individual, but it will also depend on the severity of the spinal stenosis. See X-Stop Procedure.