Spinal Stenosis

Introduction

The central nervous system is the body’s main control center. The brain is responsible for processing information based on the sensory inputs received from various organs and limbs. The spinal cord is responsible for collecting this information and relaying to and from the brain. It carries messages from the brain to various specific areas of the body. Hence, it is extremely important for these crucial organs to be protected and shielded from injury.

They have multiple levels of protection including protective membranes (the meninges), a shock-absorbing fluid that also protects from infection (cerebrospinal fluid) and a rigid bony armour (skull and spinal column). The spinal column or backbone is a curved bony structure that encases the spinal cord. It is composed of multiple segments called vertebrae separated by shock-absorbing cushions called intervertebral discs. The vertebrae all have a hollow space running through them known as the spinal canal. The spinal cord nestles within this space.

What Is Spinal Stenosis?

Sometimes, the spinal canal becomes abnormally narrow. This may be a result of age-related wear and tear or an existing skeletal disorder such as Paget’s disease of the bone. Typically, this condition occurs in middle-aged or older adults but some people may actually be born with it. Most often, it is the sections of the spine located in the neck and the lower back regions that are affected. These are known as the cervical and lumbar sections of the spine respectively. Hence, cervical and lumbar stenosis are the more common forms of spinal stenosis.

As a result of the narrowing of the spinal canal, the spinal cord is pinched or compressed and this can lead to a range of neurological disturbances such as radiating pain, tingling or numbness. The severity of symptoms may range from mild to intense. In some cases, patients are not even aware of the problem as the symptoms are fairly mild. However, in extreme cases, the patient may be left with permanent disabilities such as paralysis.

Why Does This Happen?

In some cases, spinal stenosis is a congenital condition. In other words, it is present at birth in the form of an abnormally narrow spinal canal. More often, this condition arises in middle age or even later as one of the outcomes of age-related degeneration of the skeletal structure. In such instances, the symptoms appear gradually, usually in the fifth decade of life. Symptoms are mild at first and may worsen as the individual ages further. One of the most common culprits for such spinal degeneration is a disorder known as osteoarthritis.

However, there may be a variety of other causes. In fact, any condition that results in the constricting of free space within the spinal canal could be a potential cause for spinal stenosis. For instance, the patient may develop abnormal growths within the spinal canal in the form of tumors or even bone spurs.

Here are some documented causes:

• Congenitally narrow spinal canal.
• Age-related wear and tear of the spine.
• Osteoarthritis.
• Injury to the spine causing the bone to become deformed or displaced during recovery.
• Paget’s disease of the bone.
• Tumors.
• Overgrowth of skeletal tissue, often in the form of bone spurs.
• Herniation of intervertebral discs.
• Thickening and hardening of the ligaments that support the vertebrae.

Are There Multiple Variants Of Spinal Stenosis?

Indeed, there are. The different types of spinal stenosis are identified according to the specific section of the spine that is affected. Although the spinal cord itself is a continuous structure, the bony column in which it is housed is actually made up of 33 separate segments which are grouped into four major sections. The cervical spine forms the structural support for your neck. Below this comes the thoracic spine which runs down the back of the chest. Next is the lumbar spine which forms the lower back. This is followed by the sacral spine which corresponds to the pelvic region. The final tapering portion of the vertebral column in known as the tailbone or the coccyx.

The two most common forms of spinal stenosis are those that affect the cervical and lumbar sections of the spine. Thoracic stenosis is also known but it is less often encountered in clinical practice.

What Are The Symptoms?

The spinal cord communicates with other parts of the body through what is known as the peripheral nervous system. This includes major nerves that arise from the spinal cord and then branch out to various specific areas of the body. The points where these nerves feed into the spinal cord are known as nerve roots. Each section of the spine carries its own set of nerve roots. Hence, the nature of symptoms and which areas of the body are affected by spinal stenosis is dependent on which section of the spine and which nerve roots, in particular, are suffering from compression.

Typical symptoms of spinal stenosis include abnormal sensations such as tingling, prickling or numbness in certain parts of the body. Patients often complain of a radiating pain in a particular area such as the leg and lower back. There may be some amount of muscle weakness and stiffness as well.

A group of ten pairs of nerves that emerges from the lumbar spine supplies innervation to the pelvic region and the lower limbs. These nerves are responsible for sexual function and control of the urinary bladder and bowel movements. Hence, these functions are affected when a person is suffering from lumbar stenosis. Specific symptoms of lumbar stenosis include:

• Sciatica. This results in shooting pains down the legs.
• Difficulty walking normally.
• Urinary incontinence.
• Bowel incontinence.
• Loss of the ability to lift the forefoot while walking, causing it to droop and slap the ground while walking.
• Altered gait.

Typical symptoms of cervical stenosis include:

• Difficulty maintaining balance.
• Loss of coordination.
• Shuffling gait.
• Tendency to trip.
• Weakness.
• Pain in the neck and/or shoulders.
• Bladder and/or bowel incontinence.

What Are Some Potential Complications?

The spinal cord is an extremely delicate organ and it coordinates some of the most crucial voluntary and involuntary functions of the body. In the worst case scenario, a patient with spinal stenosis may develop permanent nerve damage. They may experience one or more of the following complications:

• Muscle spasms.
• Tendency to lose balance and injure themselves.
• Bowel incontinence.
• Bladder incontinence.
• Seizures.
• Paralysis.

How Is It Diagnosed And Treated?

Your description of your symptoms may suggest a problem related to nerve compression. The specifics of the symptoms may indicate which area, in particular, has been disturbed. In order to gain clarity as to the cause of the spinal compression, the following imaging tests will be helpful:

• X-rays. These can help to reveal bone abnormalities such as the narrowing of the spinal canal, herniated discs or any bone spurs or fractures that may be involved.
• Computerised tomography (CT) and magnetic resonance imaging (MRI). These tests can help to reveal any tumors or abnormal growths that may be present.

Spinal stenosis has no known cure. However, treatment can help to alleviate symptoms such as abnormal sensations and pain. Medications can help to control seizures and muscle spasms. The inflammation as a result of compression of the spinal cord can be calmed with steroid injections. The patient may require supportive devices such as a walker or braces to help them remain mobile.

In some cases, surgical intervention may be warranted. Procedures such as laminectomy can provide relief but there is a risk of surgical complications. The patient should be fully informed of the pros and cons so that they can make an informed decision about whether or not to go ahead with surgery.

Prevention

As the body ages, it is normal to expect some amount of degeneration of the tissues. The tissues naturally lose their suppleness and ability to renew themselves rapidly. The process of replacing worn tissue becomes slower. In the case of the spine, such degeneration often manifests in the form of conditions like herniation of discs, sciatica and spinal stenosis. Unless stenosis is caused by a tumour or a bone spur which can be removed by surgery, the condition cannot be completely cured. However, surgery can be beneficial to help relieve the symptoms to a certain extent. The choice of treatment method will vary on a case to case basis and if you are experiencing symptoms consistent with spinal stenosis, you should consult your doctor for advice on how best to proceed.

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