What is sciatica?

Sciatica is the medical term for any sort of pain that is caused by the irritation or compression of the sciatic nerve, a large nerve that runs from your lower back (lumber spine) past your pelvis down your leg towards your foot. The sciatic nerve is made up from five separate nerve roots, which leave the spinal column between each of the five vertebrae which form the lumber spine.

What are the symptoms of sciatica?

Sciatic pain may present as a dull, nagging pain which runs from your lumbar spine down the back, outside, or front of your leg. It is often compared to toothache. Sharp, stabbing pains may also be experienced, often triggered by movement. Symptoms usually only occur on one side of the body, but in certain cases pain occur on both sides of the body. Sciatica may not necessarily be associated with the presence of pain in the lower back. It may also present as weakness, pins and needles or numbness that may occur in various parts of the leg and foot.

What causes sciatica or sciatic pain?

Common causes (around 90%):

  • Spondylosis / Intervertebral disc degeneration – In the majority of cases sciatic pain is due to the collapse of one or more of the rubbery pads of tough, elastic tissue situated between the vertebrae, called intervertebral discs. Under certain circumstances, especially when a sudden downwards force is suddenly applied to the intervertebral disc such as in the case of an injury or as a result of lifting a heavy object, the internal structure of the disc gives way and it ruptures or collapses. The medical terms used to describe this phenomenon are “herniated disc” or “prolapsed disc” and the general condition that leads to disc degeneration is called spondylosis. Once collapsed, some portion of the disk may bulge outwards and press on one of the five nerve roots that collectively form the sciatic nerve (See below).

Rare causes (around 10%):

  • Spondylolisthesis – the forward displacement of a vertebra, especially the fifth lumbar vertebra, most commonly occurring after a fracture. (Backward displacement is referred to as retrolisthesis.)
  • Spinal stenosis – the abnormal narrowing (stenosis) of the spinal canal that may occur in any part of the spine.
  • Piriformis syndrome – caused by the piriformis muscle, either as a result of inflammation or direct pressure on the sciatic nerve.
  • Pelvic tumors – a rare cause.
  • Pregnancy – direct compression by a baby’s head.

How is spondylosis diagnosed?

Once suspected in a clinical context, the diagnosis of spondylosis is confirmed via an imaging procedure such as an X-ray, MRI, or CT scan. The most obvious feature visible on the radiological image is the collapse or disintegration of one or more intervertebral discs, as judged by loss of height when compared to normal discs. Later features are the distortion of the bony skeleton in the immediate vicinity of the collapsed disc, caused by inflammatory damage and the growth of bony projections or spurs along the collapsed disc’s margins. These are called osteophytes and resemble the tip of a parrot’s beak in appearance.

How does spondylosis develop?

Spondylosis is often triggered by a traumatic event such as an injury, especially when a sudden downwards force is applied to a normal or healthy intervertebral disc. Examples are whiplash injuries and strains caused by the lifting of heavy objects. However, the slow but progressive deterioration of intervertebral discs over time, caused by chronic inflammation, is also major contributing factor. This is because chronic inflammation slowly degrades the basic structure of a disc and “softens” it, making the disc more vulnerable to injury. An inflamed disc also becomes increasingly less resilient to the daily micro-trauma that is caused by the usual stresses and strains of normal activity.

Which factors contribute to spondylosis?

Within a healthy spine, intervertebral discs are largely avascular and aneural, meaning that in their normal state they contain neither blood vessels nor nerves. New research has demonstrated that an early sign predicting the onset of future disease is the microscopic appearance of blood vessels and nerve fibres that progressively start to tunnel through a healthy disc. New blood vessels provide access to several inflammatory factors present in blood plasma, which result in progressive damage to the disc.

Why does inflammation damage the intervertebral discs?

Intervertebral discs are predominantly made out of protein in the form of collagen fibres. These provide a robust, mesh-like structure that accommodates other protein-based molecules making up the rest of the disc (proteoglycans & aggrecans). This unique structural arrangement enables the spine to resist the extreme tensile forces required when lifting, bending and rotating the body.

Starting at the outer, more durable layer (annulus fibrosus), the progressive infiltration of blood vessels into the pliable inner core of the intervertebral disk (nucleus pulposus) provide access to inflammatory components present in the blood stream. This activates an escalatory biochemical cascade that progressively degrades a healthy disk through powerful enzymatic action. Degradation is also accelerated by the activity of white blood cells which, under normal conditions, contain large quantities of severely caustic enzymes. These serve as the main offensive weapon used to eradicate and digest harmful microorganisms. Once these enzymes are released within the intervertebral disk, they rapidly degrade the protein-structures that the disc is made of.

Why does pain often gets worse?

The progressive infiltration of a network of new nerve fibres creates a rich network of additional neural pathways both around and within the core of the intervertebral disc. These new neural pathways then result in the signalling of pain from previously unconnected regions. Additional neural pathways also increase the volume of signals thereby enhancing the total sensation of pain. The increased nerve signals from the spinal cord to the neighbouring back and neck muscles also triggers muscle tension and spasm, which significantly aggravates pain. A vicious cycle ensues. During this process several other pain related syndromes are also likely to develop. Examples are hyperalgesia, or abnormally increased sensitivity to pain, and allodynia, during which minor stimuli such as touch and temperature, now trigger a significantly exaggerated pain response.

How is spondylosis treated?

Acute pain management

  • Anti-inflammatory drugs (NSAID’s) – these are good options to assist with acute pain. However, they should all be used with caution over the long term, since as a class, these drugs pose a significant side-effect risk relating to cardio-vascular, gastro-intestinal and kidney disease. (Ask your doctor or pharmacist for advice).
  • Analgesics – paracetamol (acetaminophen) and opiates or opiate derivatives are often required to help alleviate acute pain. These drugs serve as symptomatic relief, lowering the sensation of pain, but do not combat the underlying cause. Opiates may cause drowsiness, constipation and addiction. (Ask your doctor or pharmacist for advice).
  • Hot or cold packs – applying a heat pack to your neck can help to ease pain. You can use a microwavable heat pad or a hot-water bottle. Heat dilates the blood vessels which improves blood supply to the blood takes to the back and helps to reduce muscle spasms. Heat also alters the sensation of pain. (Some find cold packs offering better relief – for example, a bag of frozen peas).
  • Rehabilitation therapies – physiotherapy, biokinetics, or chiropractic therapy may prove helpful. A good massage may also assist. Therapy may reduce inflammation, correct posture, muscle tension, or other contributors to neck pain.

Preventative self-help strategies:

By preserving the integrity and mobility of your back you are in turn protecting it from the consequences of chronic inflammatory damage over time. Judging from the number of people in the world who become permanently disabled from chronic back ache, these easy to implement but important strategies will likely prove one of the most worthwhile investments in your overall health.

  • Stretch your back
    Stretching is a form of physical exercise during which a contracted, tight, or painfully stiff ligament or muscle group is deliberately lengthened in order to improve its elasticity and achieve a more relaxed tone. When done properly, this results in a more comfortable feeling of increased muscle control, flexibility, and range of motion. Regular stretching is an excellent way to alleviate muscle inflammation and pain.
  • Strengthen your back muscles with exercise
    Although exercise is usually not advisable for acute back pain, proper exercise can help ease chronic pain and reduce the risk of recurrence. Modern research has demonstrated that many of the benefits of exercise are mediated through the role that muscle tissue play as an endocrine (hormone producing) organ. Contracting muscles release multiple substances known as myokines which promote the growth of new tissue and facilitate tissue repair. Myokines also have multiple anti-inflammatory effects, which in turn reduce your overall risk of developing various inflammatory diseases. These anti-inflammatory effects will assist you locally with inflammation in your spine, as well as systemically in the rest of your body. Regular exercise can help reduce your risk of developing a herniated disc by slowing down their age-related deterioration as a result of chronic inflammation. It can also help keep your supporting back muscles strong and supple. Always stretch properly in order to warm up and cool down properly before and after any workout or sports activity.
  • Use supplements that naturally reduce inflammation
    Various natural molecules derived from plants are highly effective in suppressing pathways involved in chronic inflammation. These generally have a low side-effect risk, making them an attractive approach when compared to other pharmaceuticals. RheumaLin is a novel multi-modal, multi-target anti-inflammatory supplement that consists of two plant extracts, Boswellia bark extract and resveratrol. These naturally derived phytochemical (plant based) compounds are widely recognised. They combat inflammation via biochemical mechanisms that are different to those of existing anti-inflammatory drugs. A large number of high level research projects have produced strong evidence that these agents alleviate and potentially help to prevent osteoarthritis, intervertebral disc degeneration, and osteoporosis. These three separate but interlinked conditions are all caused by inflammation, and are also the three predominant causes of most cases of chronic back and neck pain. Read more about RheumaLin
  • Surgery
    In a small number of cases, surgery may be required to remove a section of a damaged prolapsed disc that is pressing on a nerve.