Spinal stenosis is a medical condition in which the bony openings in the middle of the spine progressively narrow. Eventually, these openings narrow to the point at which they start to compress the nerves that travel through the spine and carry sensory and other signals between the brain and the lower body.
The narrowing that occurs in spinal stenosis can take place in the spinal canal that runs through the middle of the spine. Alternatively, it may affect the spaces between the vertebrae (foramina) where the spinal nerves exit the canal.
Spinal stenosis can occur either in the portion of the spine that runs along the back of the neck or in the lower back (or lumbar spine) area. The former type of stenosis is called cervical stenosis while the latter is referred to as lumbar spinal stenosis. In some cases, both types of spinal stenosis may be present. However, generally speaking, lumbar stenosis is more common.
The symptoms of these two types of stenosis differ, and we shall describe these differences in detail below.
Although some individuals are born with narrow spaces that compress the nerves of the spine, this occurs only very rarely. More commonly, the narrowing occurs over time and is the result of a separate medical problem such as osteoarthritis.
In some cases, individuals affected by spinal stenosis (as determined by medical tests such as an imaging scan) experience no symptoms. However, in other cases, affected individuals may experience back pain as well as numbness, weakness or tingling sensations in the legs or back. Some individuals may also experience difficulty controlling bladder or bowel function.
The treatment of spinal stenosis can include a wide range of options. For some individuals with mild or no symptoms, doctors may recommend monitoring the condition as well as possibly some physical therapy. In others with more severe symptoms, medication, spinal decompression or other surgical options may be considered.
As mentioned above, spinal stenosis is usually a result of a separate medical condition. Some of the most commonly observed causes are:
Spinal osteoarthritis – this is a condition in which the cartilage covering the joints that connect the backs of adjacent vertebrae (the facet joints) starts to wear down. This then causes the adjacent vertebrae to start to rub directly against each other. The result of this can be the formation of unusual bone growths, or bone spurs. These spurs can in turn narrow the foramina and place pressure on the nerves exiting the spinal column.
Degenerative Disc Disease is another possible cause of spinal stenosis. It causes the spinal discs between adjacent vertebrae to flatten and bulge into the spinal cord. The flattening narrows the foramina while the bulging narrows the spinal canal itself. The result of both developments is increased pressure on the spinal nerves, which then produces the symptoms of spinal stenosis.
Thickening of spinal ligaments -This is a condition under which the ligaments in the spinal canal harden and eventually turn into bone-like tissue. As this happens, the thickened ligaments encroach into the spinal canal and press on the nerves travelling through the canal.
Paget’s disease is a condition that results in bone overgrowth in the spine. This too can reduce the space in the spinal canal and cause stenosis.
In addition to the above causes, spinal stenosis can in some cases be the result of a previous trauma to the spine. For example, an auto accident can sometimes cause spinal injuries that later lead to stenosis.
Another occasional cause of spinal stenosis can be the development of one or more tumours in the spinal cord. These tumours can then encroach on the space needed for the nerves occupying the spinal column.
Symptoms Of Spinal Stenosis
As mentioned above, some patients may experience no symptoms of spinal stenosis.
For others, however, there may be tangible symptoms that depend on whether the stenosis is in the cervical or lumbar region of the spine.
If the stenosis is in the cervical region, the symptoms can include:
Numbness, tingling or weakness in the arms, hands, feet or legs;
Trouble maintaining balance, especially while walking;
To formally diagnose spinal stenosis, a doctor will likely make use of the following:
Patient medical history. This will be reviewed carefully, with a particular eye for previous back injuries and the symptoms the patient reports experiencing;
Physical examination of the spine and lower back. This may include assessing spinal range of motion as well as leg/arm strength, reflexes and sensory perception in the arms and legs.
One widely used procedure is Spurling’s test. This involves testing the neck by rotating the head towards the symptomatic side, then moving it into extension and finally applying gentle pressure to the top of the head. The patient is then asked to report whether he or she is experiencing any pain and, if so, what type.
Medical imaging of the spine. The most common type of medical image is the MRI but a CT scan may be employed if an MRI is not practicable for some reason.
As mentioned above, many cases of spinal stenosis (even though confirmed by imaging) are not accompanied by tangible symptoms. In such cases, doctors may opt to continue observing the patient via repeat visits.
Treatment of spinal stenosis cases with tangible symptoms normally involves a combination of physical therapy, pain relief medication, activity modification and epidural injections. If these do not relieve the symptoms and the pain becomes severe, doctors will probably start to consider surgical options.
This is a part of virtually every treatment plan for spinal stenosis. It will not cure the underlying condition but will prevent the patient becoming further debilitated as a result of insufficient activity.
The main goal here will be to avoid activities that may worsen symptoms of the stenosis. Patients suffering from lumbar stenosis, for example, may be encouraged to adopt activities that they can perform while leaning forward. These may include walking or stationary biking.
Common over the counter medications may be prescribed in order to relieve pain. These may include Tylenol or Non steroidal anti inflammatory drugs such as aspirin or ibuprofen.
For severe nerve related pain, doctors may prescribe opioid medications, muscle relaxers or nerve desensitizing medications. However, side effects are always a risk and careful monitoring for them is a must.
These injections into the spinal canal are performed with the goal of reducing inflammation of the nerve roots and/or the spinal cord.
There is a range of surgical options for treatment of spinal stenosis. The goal of all of them is to reduce compression of the spinal column and the nerves in it. By so doing, surgeons hope that the nerves will start healing and functioning properly.
Probably the most common surgical procedure is a laminectomy, which involves removal of part of the vertebrae in order to decompress the spinal cord.
Another possibility is spinal fusion, which is normally performed when the cause of the stenosis is degenerative disc disease. The degenerated disc is removed and the adjacent vertebrae are then fused together.