Spinal Cord Stenosis

Spinal stenosis is a specific condition characterized by the narrowing of spaces in the spine — stenosis actually means narrowing! This narrowing results in pressure on the spinal cord and nerve roots which can lead to a number of problems, depending on the nerves which are affected. Spinal stenosis is most common in the neck and lower back areas, though it can also affect other areas of your spine.

The symptoms of spinal stenosis may include muscle weakness, numbness, pain, and a tingling sensation. Though not everyone with spinal stenosis actually reports symptoms and they gradually appear.

What else should you know about spinal stenosis?

In great majority of patients, spinal stenosis is accompanied with cramping, pain or numbness in legs, back, neck, shoulders or arms; a loss of sensation in extremities; and sometimes problems with bladder or bowel function.

In most cases the mild symptoms of spinal stenosis are often helped by pain relievers, physical therapy or a supportive brace. However, in more serious cases of spinal stenosis, doctors may recommend surgery.

This disorder usually involves the narrowing of one or more of three areas of the spine:

1.    The narrowing can affect the canal in the center of the column of bones through which the spinal cord and nerve roots run. It is also called a central vertebral canal!
2.    This narrowing can also affect the canals at the base or roots of nerves branching out from the spinal cord
3.    The openings between vertebrae through which nerves leave the spine and go to other parts of the body can also be affected. The narrowing may involve a small or large area of the spine.

The pressure on the lower part of the spinal cord or on nerve roots branching out from that area may give rise to pain or numbness in the legs. Pressure on the upper part of the spinal cord may produce similar symptoms in the shoulders, or even the legs.

Different types of stenosis

There are three different types of stenosis and they include:

Foraminal stenosis
When a bone spur presses on the nerve root in the point where it is about to leave the canal through a side hole we have foraminal stenosis. It is also called lateral spinal stenosis.

This is by far the most common form of spinal stenosis and 72% of cases of foraminal stenosis occur at the lowest lumbar level.

Central stenosis
If the narrowing of the central canal compress the sack of the horse’s tail called cauda equina the condition is called central stenosis. Central spinal stenosis is more common at the second lowest lumbar spinal level and above.

Far Lateral stenosis
This is not such a common type of stenosis. In this case the nerve is compressed on the outside of the spine after it has left the spinal canal. The cause of compression could be from either a bony protrusion or disc bulge.
 

Signs and symptoms of Spinal cord stenosis

Spinal narrowing doesn't always cause problems. Problems or symptoms appear only if the narrowed areas compress the spinal cord or spinal nerves. These often start gradually and grow worse over time.

The most common include:

Pain or cramping in the legs
Compressed nerves in your lower spine can lead to a condition called pseudoclaudication which is characterized by pain or cramping in legs when patient is standing or walking for a long time. There is also another type of intermittent claudication which occurs when there's a narrowing or blockage in the arteries in the legs. Although both types of claudication cause similar symptoms, there is one important difference - this type of claudication becomes worse when a patient walks up-hill and improves when standing still. Pseudoclaudication is usually worse when going downhill and gets better when you lean forward or sit down.

Radiating back and hip pain
A herniated disk can compress nerves in lumbar spine, leading to pain that starts in hip or buttocks and extends down the back of leg. The pain is worse when you're sitting and generally affects only one side. Some patients also may experience numbness, weakness or tingling in leg or foot. 

Pain in the neck and shoulders
This is likely to occur when the nerves in the neck are compressed. The pain may occur only occasionally or it may be chronic, and it sometimes can extend into arm or hand. Some patients also reported headaches, a loss of sensation or muscle weakness.

Loss of balance
Pressure on the cervical spinal cord can affect the nerves that control patient’s balance. That’s why many patients complain on clumsiness or a tendency to fall.

Loss of bowel or bladder function
In severe cases, nerves to the bladder or bowel may be affected, leading to partial or complete urinary or fecal incontinence. This happens when the damage is in the low back affecting cauda equina.

Possible causes of spinal cord stenosis

Osteoarthritis
The main cause of spinal degeneration is osteoarthritis, an arthritic condition which affects the cartilage that cushions the ends of the bones in joints. When body tries to help and repair the damage, it may cause even more damage because it does so by producing bony growths called bone spurs which then narrow the spinal canal.

Herniated disk
It is proven that by the age of 30, disks may start to show signs of deterioration. These bony formations begin to lose their water content, becoming flatter and more brittle. With time, disk's center to seep out which is causing pressure on the surrounding nerves, causing pain in the back, legs or both.

Ligament changes
The ligaments in the back can undergo the same degenerative changes as bones. They are becoming stiff and thick over time. This loss of elasticity may shorten the spine, narrowing the spinal canal and compressing the nerve roots. 

Spinal tumors
Tumors can also form inside the spinal cord, within the membranes that cover the spinal cord, or in the space between the spinal cord and the vertebrae. Whether they are primary or metastastic, tumors can occur anywhere along the spine, including the sacrum and thoracic spine, where osteoarthritis is rare. Growing tumors may compress the spinal cord and nerve roots. This can lead to several problems in sensory and motoric system.

Injury
Trauma can significantly affect the spine and spinal cord. Sometimes the spine or spinal canal may be dislocated, putting pressure on the cord and lower motor neurons. Results are devastating.

Paget's disease of bone

Because bone is also a living tissue, old bone cells are constantly being removed and replaced by the new ones. In Paget's disease, the body generates new bone at a rate that is faster than normal. This produces soft, weak bones that are prone to fractures. It can also create bones that are deformed or abnormally large. 

Achondroplasia
This isn't such a common condition, and it is caused by the slowing in the rate at which bone forms during fetal development and in early childhood. As a result, people with achondroplasia are of short stature.
 

Diagnosis of Spinal cord stenosis

Spinal X-ray
This diagnostic tool isn't that helpful in making the right diagnosis but it can help in ruling out problems that cause similar symptoms, including a fracture, bone tumor or inherited defect.

Magnetic resonance imaging (MRI)
This is probably the best possible imaging test for diagnosing spinal stenosis. Instead of X-rays, an MRI uses a powerful magnet and radio waves to produce cross-sectional images of your back.   

Computerized tomography (CT) scan
Similarly to X-ray- this test uses a narrow beam of radiation to produce detailed, cross-sectional images of body.

CT myelogram
This may be the most sensitive test for detecting spinal stenosis, but it poses more risks than either MRI or CT.
A contrast substance is injected in the spinal column and while the substance circulates around it and the spinal nerves an imaging is being done!   

Bone scan
In this test, a small amount of a radioactive material is injected into vein in patient’s arm. The material emits waves of radiation that are detected by a gamma camera. 

Treatment

Treatments for spinal stenosis could be divided into two big groups. One is surgical and the other is non-surgical methods.

Non-surgical methods

• Nonsteroidal anti-inflammatory drugs, such as Aspirin®, naproxen (Naprosyn®), ibuprofen (Motrin®, Nuprin®, Advil®), or Indomethacin (Indocin®), to reduce inflammation and relieve pain.
• Analgesics, such as acetaminophen (Tylenol®), to relieve pain.
• Corticosteroid injections to reduce inflammation and treat acute pain that radiates to the hips or down a leg.
• Anesthetic injections to temporarily relieve pain.
• Restricted activity
• Prescribed exercises and physical therapy   
• A lumbar brace or corset to provide some support and help the patient regain mobility

Surgical solutions

Decompressive laminectomy

This procedure is in most cases the best option. In this procedure, surgeon removes the back part of the bone over the spinal canal to create more space for the nerves and to allow access to bone spurs or ruptured disks that may also be removed. There are some risks such as infection, a tear in the membrane that covers the spinal cord, bleeding, and a blood clot in a leg vein.

Laminotomy

In this procedure, a portion of the lamina is removed to relieve pressure or to allow access to a disk or bone spur that's pressing on a nerve. 

Fusion

This method is used to permanently connect two or more vertebral bones in spine.