As with other joints in the body, the spine undergoes age related wear and tear. As we get older the intervertebral discs become dehydrated and loose some of their height. This means that they are no longer acting effectively as spacers and shock absorbers, and the disc can often bulge backwards. The loss of disc height puts an increased load on the facet joints. The facet joints are the small joints in the back of your spine that help to stabilise your spine whilst allowing movement. The facet joints can become swollen and arthritic. There is also associated buckling and thickening of the ligamentum flavum, which is a structure that runs between the bones in the back of your spine. This combination of a disc bulge, swollen facet joints, and ligament thickening has the effect of narrowing the space available for nerves in the spinal canal. The spinal canal can become so tight (stenotic) that the nerves become compressed and their blood supply becomes compromised, resulting in spinal claudication. Spinal claudication is nerve pain in the legs caused by poor blood supply to the nerve. Other symptoms include numbness and tingling in your legs, and leg heaviness / weakness when walking. The symptoms of stenosis are often bought on / made worse by standing and walking, and relieved by rest. It is common for the symptoms of stenosis to wax and wane. In other words, on some days your symptoms may be much better than on others.
Spinal stenosis is a chronic degenerative condition and does not suddenly develop following an acute event. However, an acute event may trigger the onset of your symptoms. Patients with spinal stenosis generally experience a gradual deterioration in their symptoms and function. The most common symptom is a restricted walking distance due to worsening leg pain.
Assessment of Stenosis
Stenosis is assessed by taking a detailed history of your symptoms, followed by a physical examination. The history will include questions about the onset of symptoms, as well as the current level of symptoms. It is normal to be asked about your bladder and bowel function. This enquiry relates to loss of control rather than change in regularity. It is not uncommon for patients taking painkillers to become constipated, and for patients with back pain to need to go to the loo more frequently. There should also be questions aimed at excluding other causes of your symptoms. You will also be asked about other medical problems, medications that you are taking, whether or not you have any allergies, and if you smoke.
The examination will include checking your legs for strength and sensation, as well as assessing your reflexes. If there are any concerns about loss of control of bladder or bowel function, then it may be necessary to perform a rectal examination.
Whilst the history and examination findings are frequently suggestive of a diagnosis, in any patient in whom treatment is being considered this diagnosis needs to be confirmed by an MRI scan.
Physiotherapy, chiropractic treatment, osteopathy. A slight improvement in posture may create more space for the nerves and allow the symptoms to settle down. If this allows your symptoms to settle down, then you may well require no further treatment for the time being.
An injection of steroid and local anaesthetic around the nerves aims to reduce the inflammation in the nerves, allowing the painful symptoms to settle down. An injection would not normally help with any sensory symptoms (such as numbness), or difficulty walking. The injection would typically be a foraminal epidural +/- a caudal epidural. These injections are effective in approximately 65% of patients. Your response to the injection determines what further treatment you will be offered: if you have complete relief then you will need no further treatment for the time being; if you have relief for several months before a gradual return of your symptoms then the injection can be repeated; if you have no relief or short lasting relief then we need to consider other options. If your stenosis is very severe then it may not be appropriate for you to have an injection.
As stenosis is a degenerative condition, even if you have good relief following either physical therapy or injections, unfortunately there is a chance that your symptoms may return at some point in the future.
The final option is surgery. This is indicated in patients who have stenosis and have not had good relief following an injection. It is also indicated in patients who have severe stenosis. Occasionally, it may be necessary to perform a spinal fusion in addition to the decompression.