Understanding Sciatica: Sciatic Nerve Pain Causes & Treatments

Sciatica is pain caused by irritation or compression of the sciatic nerve. In medical terms it is known as lumbar radiculopathy. Pain can be felt in the lower back, hips and legs. Sciatica can cause major discomfort and in some cases disability.

What is the Sciatic Nerve?

The sciatic nerve is a major nerve, the largest single nerve in the whole body. As with all nerves, its function is to transmit nerve pluses between the central nervous system (CNS) and the tissues it innervates (supplies with nerves). Due to its size, the sciatic nerve is responsible for connecting a large area of the body with the CNS. This includes nearly all the skin of the leg, the hamstring muscles in the thigh, as well as muscles in the leg and foot; movement and sensations from the CNS to these areas via the sciatic nerve.

The sciatic nerve has its roots in the lumbar and sacral region of the spine, deriving from spinal nerves L4 to S3; it extends from the lower back region (lumbosacral plexus), through to the buttock area and down into the lower limb, where it divides, branching off into other nerves just above the knee joint. The sciatic nerve is also responsible for innervating other nerves in the lower leg, such as the tibial nerve and the common peroneal nerve.

What are the Symptoms?

When the sciatic nerve becomes irritated or compressed, it can produce a variety of symptoms. These range from; numbness and feelings of pins and needles to tingling and shooting pains, radiating from the lower back into the legs and reaching as far as the feet and toes, depending on where the nerve has been affected. Pain caused from sciatica is generally felt in the buttocks and legs rather than in the back itself, although it can cause general lower back pain. Pain is also felt more commonly in only one leg, or on one side of the buttocks, it is rarely felt on both sides or in both legs.

Many patients report a relief in symptoms when lying down, but the pain usually worsens when sitting or standing. Intensity of pain varies from patient to patient, some may only experience mild symptoms, whereas others may suffer from sharp excruciating pain that can be debilitating. Patients suffering from severe shooting pains in the leg may find it difficult to stand or walk.

Possible Causes of Sciatica

Compression or irritation of a spinal nerve in the lower back region is referred to as sciatica. A common cause for this is irritation of the nerve root (the radicular nerve). A herniated disc for example, presses onto the nerve root which causes sciatica or in more technical terms, radiculopathy.

Herniated Disc in the Lumbar Region

Also known as slipped disc, bulging disc or pinched nerve, this is one of the more common causes of sciatica. In the spinal column, between each vertebrae are intervertebral discs. These discs function as cushions to protect the vertebrae from grinding against one another as well as acting as shock absorbers. The exterior of the disc is made of a tough fibrous substance which protects the jelly like substance in the nucleus. A herniated disc is when a crack or tear occurs in the exterior fibrous ring, causing the jelly like substance of the central portion to protrude through the crack, bulging out and compressing nerve roots.

Degenerative Disc Disease

As we age, the gel like substance in the nucleus of the intervertebral discs, begins to dry out causing the discs not only to shrink, but to become more fragile and therefore more susceptible to herniation; leading to irritation and compression of nearby nerve roots, including the sciatic nerve.

Spinal Stenosis

A less common cause of sciatica, usually caused by age related changes to the spine, spinal stenosis is a result of the narrowing of the passages where the spinal cord travels down the spine. It does not always affect the sciatic nerve.

Spondylolisthesis

This condition occurs when one of the spinal vertebrae slips out of place, it can happen at any part of the spine, but if it compresses the sciatic nerve, it can cause sciatica.

Sacroiliac Joint Dysfunction

This is a different condition to sciatica, it however, produces similar symptoms; it is caused by inflammation of the sacroiliac joint, rather than the compression of nerve roots as is the case in sciatica. The inflamed sacroiliac joint causes the portion of the sciatic nerve that runs directly in front of the joint to become irritated and produce sciatic like symptoms.

Cauda Equina Syndrome

This is a rare and extremely serious condition; swelling and pressure on a bundle of spinal nerves and spinal nerve roots at the end of the spinal cord causes the compression of these nerve endings. If left untreated it can cause paralysis and permanent loss of bladder and bowel control. When the sciatic nerve is compressed it can cause sciatica.

Pregnancy

Sciatica is not particularly common during pregnancy, but can occur. Weight gain from the expanding uterus and increased fluid retention can put pressure on the sciatic nerve.

Other Possible but Uncommon Causes

  • Tumours – a growth within the spine can cause compression of the nerves
  • Trauma to adjacent bones and muscles
  • Infections in around the lumbar region
  • Internal bleeding

Sciatica Treatments

Most patients suffering from sciatica find that their symptoms do not last more than a few weeks, in some cases treatment is not necessary and symptoms will resolve themselves. If symptoms do continue to persist, there are a number of treatments available.

Exercise

Regular exercise is good for our general well being. Keeping physically active is also important for most back related problems including sciatica, even though it may be painful to remain active. Prolonged bed rest is not considered helpful.

Physiotherapy

A good physiotherapist can help improve symptoms of sciatica in a number of ways including: using certain stretches and exercises to help strengthen surrounding muscles, help improve a patient's posture as well as teaching the patient how to integrate specific exercises and habits into their daily routine.

Pain Medication

There are a number of pain relieving medications useful in the treatment of sciatica

NSAIDS (non-steroidal anti-inflammatory drugs)

These can be effective in treating the inflammation caused by sciatica

Opioids

Opium derived medication such as codeine may be used in some cases

Other medication indicated for nerve pain may also be effective such as:

Tricyclic Antidepressants

Anticonvulsants

Spinal Injections

Anaesthetic or corticosteroid injections can be used to treat sciatica. The two medications can be combined to form a strong anti-inflammatory and pain killing medication. This is then applied directly to the affected area, providing temporary pain relief and releasing the pressure on the sciatic nerve.

Surgery

In many cases there is no diagnosable cause of sciatica, however in cases with clear diagnosis, such as that of a herniated lumbar disc; and providing other possible treatments have proven ineffective, then surgery may be a possible option.

Surgery carries with it, its own risks and potential complications and is usually a last resort.

Types of surgery that may be considered in the treatment of sciatica with a clear diagnosis include the following:

  • Discectomy – part of the herniated disc that is pressing on the nerve is removed
  • Fusion – vertebrae that have slipped out of place can be fused together with other vertebrae
  • Laminectomy – sometimes used in the treatment of spinal stenosis, the lamina on the vertebrae is removed

Pain Management Clinics

Pain management clinics work using a multidisciplinary approach; one or more of the above mentioned treatments can be used in a pain management program to treat a variety of pain related conditions including sciatica. A pain management specialist like Dr. Mark Miller will be able to help diagnose and tailor a specific plan of action to treat each individual patient.

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