Spinal Stenosis

This term refers to any condition which results in narrowing around the spinal cord or spinal nerves resulting in a group of symptoms termed claudication. Claudication is the symptom of leg pain which occurs with standing or walking and improves with rest, sitting down or leaning forward.

These symptoms can be caused by pressure on the spinal nerves ( spinal claudication ) as well as constriction of blood vessels in the legs ( vascular claudication ). Your surgeon will conduct a clinical examination and may request special investigations, such as an MRI scan to be certain of the cause of the claudication symptoms before suggesting treatment.

What are the symptoms of spinal stenosis?

Patients typically complain of pain or heavy aching in the calves or thighs which occurs with walking. With time, the symptoms start to develop with shorter distances of walking and amy be slower to resolve with rest.

These symptoms may improve with leaning on a shopping trolley and some patients will notice that they do not occur with riding a bicycle. This is due to the fact that slight leaning forward tends to open up the spinal canal which releases pressure on the spinal nerves. Occasionally the symptoms are intermittent and last for a few weeks and then resolve followed by a further episode some time later.

Eventually the symptoms progress and occur on standing upright and may progress to not improving regardless of position. Some patients may complain of aching in the calves while sleeping which may wake them at night. These may be described as cramping or heaviness.

When the condition occurs in the neck, pressure on the spinal cord may produce similar symptoms but in the arms rather than the legs and only later when severe are the legs affected. This can be in the form of unsteadiness with walking, dropping things all the time and occasionally sudden shooting pains up and down the neck and back. Tightness around the spinal nerves can produce neck pain and headaches too.

The condition tends to progress rather than resolve spontaneously but this progression is slow and so patients don’t usually need to rush into having treatment unless the symptoms are particularly troublesome. However, with prolonged severe pressure on the spinal cord, permanent damage can occur which does not improve with surgery and therefore you may be advised to have surgery before this stage is reached.

What is occurring to the spine?

As degenerative changes develop in the spine, general structural changes occur in the disc which then breaks down and narrows and looses its ability to work as a cushion between the vertebrae. The disc bulges outward toward the spinal canal. Degenerative/ arthritic changes occur in the facet joints and the ligmentum flavum ( thick protective ligament behind the nerves) hardens and bulges inwards. All these result in narrowing of the space available to the nerves. When the patient walks there is typically an increase in the blood flow to the nerves which increases their size which further narrows the space available to the nerves and the further the patient walks the more the nerves are affected. Patients then start experiencing pain or aching along the course of the particular nerves that are affected and may also feel pain in the back or neck. Because it is a degenerative condition, this tends to occur later in life and spinal stenosis is the most commonly treated spinal condition in people over the age of 60. There are however other conditions that may result in a similar narrowing of the spine so that any age group may be affected by the symptoms of spinal claudication.

What conditions may be confused with spinal stenosis?

• Vascular stenosis due to narrowing of blood vessels.

• Arthritis of the hips or knees.

• Diabetic neuropathy.

• trochanteric bursitis due to inflammation of the tissues around the hips.

There are a number of other conditions and your surgeon will ensure the diagnosis is correct prior to considering surgery.

What is the best treatment?

Like all spinal conditions there are either conservative or surgical options and a conservative approach is usually followed in the first instance. This may involve combinations of anti-inflammatory medication, physiotherapy, steroid injections and nerve blocks. None of these will change the underlying condition causing the symptoms but are rather aimed at improving symptoms of pain.

Surgery involves relieving the pressure on the nerves and spinal cord and a number of techniques can be used depending on the underlying condition of the spine. Typically a decompression of of the nerves is required and in some conditions of spinal instability leading to stenosis, the spine may also require stabilisation in the form of a fusion.

There is evidence that surgery is likely to produce the best outcomes in the long term but delaying surgery in the first instance does not worsen the outcome when surgery is eventually chosen. There are some special instances where surgery will be suggested urgently to avoid permanent spinal cord damage but this very unusual.

Are there any minimally invasive techniques available?

There are some techniques available that can be used in certain patients and these include interspinous distraction devices and micro-decompression surgery. These are not suitable for all patients and you should be able to discuss this at your consultation.