Spinal stenosis is a term used to describe a narrowing of the spinal canal that gives rise to symptoms of compression of the spinal nerves or sometimes the spinal cord. Narrowing that affects the spinal cord is also sometimes called a myelopathy. Spinal stenosis is quite a common problem particularly with older people, (however it can affect younger people but more rarely.)
The symptoms experienced are those of back pain and leg pain. Most typically it occurs as you walk a pain and will cause numbness or weakness or feelings of unsteadiness sometimes in both legs sometimes in just one.
Claudication is the term used by doctors for weakness of the legs that gets worse specifically on walking. Common causes are vascular due to narrowing of the blood vessels or spinal due to bone overgrowth causing a reduction in the space for spinal nerves.
Classically the sufferer can walk a certain distance (sometimes 50m or further- say -500m) and then they need to stop because the pain & numbness intensifies.
Most find that sitting down or leaning forward enables them to recover so that they can then walk again.
Some also get these symptoms on standing.
Also usually patients have no pain in the leg at rest.
(Back pain is not the same however and increased back pain on walking is not a feature of spinal stenosis.)
Usually as part of the natural aging process we develop degenerative change in the lower back.
Sometimes these changes lead to a partial constriction -or a “stenosis”- of the nerve tunnel within the spine which is called the central canal that is “central stenosis”.
Others suffer a slightly different constriction to the smaller side tunnels with the spine which is called “foraminal stenosis”.
Practically speaking the symptoms of each or these two types are essentially the same.
Normal central canal - Narrow central canal
The nerves within the spine are both compressed by the constriction & also their blood supply is temporarily reduced by the compression.
This leads to the pain on walking, as the tunnels in the spine are smaller when you are erect, but larger on sitting with the spine bent.
The problem is firstly assessed by your GP who makes a clinical diagnosis, then usually asks the opinion of a hospital specialist, who assesses & requests an MRI scan & or rarely CT scan which confirms the problem.
Central canal stenosis at one place (level) in the lower back.
Some patients can have more than one level affected.
The course of the problem has some uncertainty, but a general rule can by applied that 1:5 will improve with time, 3:5 will stay the same, &1:5 will worsen with time.
Worsening is usually that the walking distance will reduce gradually & sometimes the nerve supply to the leg will become increasingly affected.
his condition is a ‘quality of life’ issue. If your symptoms are acceptable to you then no interventions may be needed.
Most specialists would suggest you start with simple less risky treatments first.
Improving spinal mobility, strength & overall fitness
Improving pain control
Spinal mobility & stability exercises performed routinely.
Static bike cycling little and often to start with. Patients can often cycle without as much leg pain as when they walk. The use of an exercise bike can enable improvement in fitness and leg muscle tone. Start with just two or three minutes twice a a day, and increase the time a little each few days.
Walking as best as possible.
Weight loss if applicable.
Some patients improve by these simple measures, and if surgery was needed being as fit and well as possible means that surgery would be safer as you, the patient, would be fitter.
Simple pain control, using over the counter medication such as paracetomol or ibuprofen.
An ‘umbrella ‘ of pain relief using a combination of tablets will often be more helpful than trying to rely on just one type of medication.
Nerve pain control.
Doctors can prescribe Nerve pain modifying drugs e.g. Amitriptyline, or Gabapentin etc.
Some patient’s leg pain can lessen with a proper course of such therapy.
A recent randomised controlled trial published in the journal ‘Spine’ showed that Gabapentin was definitely helpful when combined with a fitness and exercise program compared to placebo.
Walking up to symptom threshhold then just a little further despite the pain will often improve walking distance over time.
It may take a few months before it is clear if these simple measures are helpful.
Remember it will hurt , but you won’t harm it!
If indicated spinal injections e.g. Root Canal or Epidural, steroid & local anaesthetic can also help some patients.
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 rather than 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.
Often by blocking the nerve pain with anaesthetic the symptoms will improve permanently or for quite a while. About 60% of patients will respond well. They are low risk procedures and can be repeated.
Recent studies have suggested the same treatment effect can occur with injecting local anaesthetic alone rather than anaesthetic and steroids.
These injections are usually requested by the hospital specialsit . They may occur in the clinic or in the X-ray department.
Treatment tends to be graded to severity of symptoms. Pain can be very distressing, so pain control is important.
If symptoms remain unacceptable despite all the simpler measures or if symptoms get worse then surgery can be quite helpful. In consideration of surgery your general health and fitness is important.
There are some new surgical treatments such as interspinous distraction devices. The NICE guidelines are available on this website.
This is a less invasive procedure than a spinal decompression operation. 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 fopr an individual. Usually you would just be in hospital overnight.
The ‘Gold standard’ operation for spinal stenosis is a decompression. This is where the bone that is compressing the nerves is removed to give the nerves more room. It can be very helpful if you are bad enough.
Generally surgey is better for leg pain than for back pain. The specific details of surgery needs to be discusssed with someone who is familiar with doing that type of surgery. Usually a surgeon with a special interest in spinal surgery.
Factors to consider
- How well you are? Other diseases & problems.
- Your general fitness.
- Is the problem one area of the spine or multiple areas?
Other Possible Causes of Symptoms
Vascular claudication. Sometimes narrowing of the blood vessels to the legs can produce similar symptoms, particularly in smokers. Stopping smoking will often improve matters.
Numbness in the legs and unsteadiness can sometimes be caused by diabetes or vitamin B12 deficiency. These conditions can be excluded by a simple blood test.