Lumbar canal stenosis (or spinal canal stenosis) is a narrowing of the spinal canal that contains the spinal cord and nerve roots.
The stenosis can press on the spinal cord and the nerves running through the spine.
These disorders most often occur on the neck and lumbar spine.
Spinal stenosis is the narrowing of at least one of the two areas of the spine where the nerves run:
- The canal in the middle of the spine that contains the spinal cord and nerve roots.
- The openings between the vertebrae (bones of the back) through which the nerves exit the spine and lead to the other areas of the body.
There are two types of spinal stenosis: cervical stenosis and lumbar stenosis. While lumbar stenosis is much more common, cervical stenosis is much more dangerous because it compresses the spinal cord even in the uppermost area.
Who suffers from spinal stenosis?
This condition is most common in men and women from the age of 50. However, it can also occur in younger people who have already been born with a narrowed spinal canal or have suffered a spinal injury.
What causes lumbar canal stenosis?
The most common causes of spinal canal stenosis are osteoarthritis or degeneration of the intervertebral disc.
As with other body joints, osteoarthritis often occurs in the spine as part of a normal aging process.
Osteoarthritis can lead to the loss of cartilage between the corresponding bones of the joints, the formation of a bone spur (osteophyte), the reduction in height of the intervertebral disc between the vertebrae of the spine (degenerative disc disease, also known as spondylosis) and increased growth (hypertrophy) of the ligament structures.
The degeneration of the lumbar discs can cause spondylolisthesis: the displacement of a vertebra over the underlying vertebra can, in the worst case, lead to instability and neurological symptoms.
These complaints can reduce the space normally available for the nerves in the spinal canal. The consequence is direct compression on the nerve tissue, which causes the symptoms of lumbar canal stenosis.
Spinal stenosis can also be caused by other conditions that reduce the space in the spinal canal or vertebral hole.
These diseases are:
- Rheumatoid arthritis. Rheumatoid arthritis usually affects people under the age of 60 and causes inflammation of the soft tissues and synovial membrane of the joints (synovitis). Even though this is not a common cause of spinal canal stenosis, the damage to the ligaments, bones and joints begins with synovitis. The sections of the spine with the greatest mobility (for example, the cervical spine) are most often affected by rheumatoid arthritis.
- Tumors (abnormal tissue formations in the structures that form the spinal canal).
- Disorders of bone metabolism of various types cause bone growth, such as Paget’s disease.
However, these causes are much less common than osteoarthritis.
Symptoms of spinal canal stenosis
- Backache. People with spinal canal stenosis do not always have back pain. That depends on the degree of osteoarthritis.
- Burning pain in the buttocks and legs (sciatica). The pressure on the spinal nerves can cause pain in the areas where the nerves go.
The discomfort is described as pain or burning sensation. As a rule, they begin in the buttocks and radiate into the legs.
The pain that runs along the legs is called “sciatica”.
In the further course, the pain can also occur in the foot.
- Numbness or tingling ants in the buttocks and leg. With increasing pressure on the nerve, numbness and tingling are often accompanied by burning pain. Not all patients will have all symptoms at the same time.
- Weakness in the legs or “tripping legs”. Once the pressure reaches a critical point, you may feel weakness in one or both lower extremities. Some patients trip over a foot or feel that the foot drags on the floor while walking.
The pain decreases when you lean forward or sit.
Studies on the spine show that bending forward expands the space required for the nerves.
Patients feel relief when lying or sitting.
The pain worsens when standing or walking.
Some patients may ride a bicycle or walk supported on a walker. Even a walk around 1 or 2 blocks can lead to severe sciatica pain.
Severe cases of spinal stenosis can lead to incontinence and paralysis.
Diagnosis of spinal canal stenosis
The physical examination consists of checking the range of motion of the back and palpation to find out the numb areas.
The legs can be examined and their range of motion, strength, sensitivity and reflex behavior tested.
Flanks and knees should be examined because problems of these joints can show symptoms similar to those that occur in lumbar stenosis.
After the examination, the doctor may order technical examinations to verify anatomical signs of lumbar canal stenosis.
The first examination is a simple X-ray of the back.
Doctors may also order an X-ray of the patient’s pelvis, depending on what was suspicious during the physical examination.
The X-ray can provide the doctor with various signs associated with spinal stenosis, including loss of height of the intervertebral disc, the presence of bone spurs (osteophytes), and spinal instability (abnormal movement between vertebral bodies).
The final diagnosis of lumbar canal stenosis is made by MRI (magnetic resonance imaging) or CT.
These advanced examination methods make the nerves of the back visible and can show whether they are narrowed by lumbar stenosis.
In some cases, special nerve examinations are performed: electromyography (EMG) or a study of nerve conduction velocity.
These examinations may reveal damage or irritation of the nerves as a result of compression of lumbar canal stenosis.