Sciatica is the name given to a painful syndrome caused by the compression, at one point or another, of the largest nerve in our body. This giant nerve is formed by the combination of nerves leaving the spinal cord between the L4 to S3 segments of the spinal cord, or in simple words, it is formed by the combination of several nerves in the lower back. The lower back is one of the most susceptible areas to strains and sprains due to immense pressure and high levels of movement.

The sciatic nerve provides sensation to most of the leg and is also responsible for the movement of several muscles in the leg. The most common cause of sciatica is compression of the nerve where it leaves the spine, either due to a herniated disc or changes in the vertebral bone.

Common symptoms of sciatica

In most cases of sciatica, the pain is severe and there may even be changes in bladder and bowel movements. Sciatica is characterised by pain that starts in the lower back and radiates down the buttocks to various parts of the legs, most commonly to the back of the thigh and calf. This typical painful syndrome is diagnostic in most cases. In most cases, only one side of the leg is affected, although in some cases the pain may be bilateral.

The intensity and nature of the pain varies from person to person. Some people describe it as a burning sensation, while others describe it as a sharp pain. This variance in pain is due to different types of nerve fibres being compressed. Usually, pain in the leg gets worse after sitting for a long time. Sneezing or coughing can make the pain worse.

Factors that increase the risk of sciatica

In addition to the pain syndrome, the doctor would also take into account various risk factors. Spinal conditions such as sciatica are relatively common in the older generation. Obesity puts more strain on the lower spine and therefore increases the risk of sciatica; certain jobs that involve lifting also increase the risk of sciatica; a sedentary lifestyle and diabetes are also risk factors, as they weaken the spinal bones and supporting muscles.

Clinical diagnosis of sciatica

After taking the patient's medical history, the doctor would carry out a physical examination. This would include testing various reflexes and muscle strength. During the examination, the doctor may ask the patient to walk on their toes, on their heels, to squat, to lift their legs while lying on their back. In the case of sciatica, the pain would get worse while doing these activities. With the history and examination, the doctor would be able to guess the location of the spinal compression. However, the doctor would use modern imaging techniques to make an accurate diagnosis.

Imaging tests used in sciatica

Usually, people go to the doctor when rest and self-treatment with common painkillers have not helped, and the pain has been bothering the person for days or even weeks. Therefore, most doctors would refer a person to the laboratory for imaging.

• X-ray: It is one of the oldest imaging techniques and is useful for showing changes in bone, whether it is bone growth or changes in density (strength).
• MRI: It is one of the most advanced and precise forms of imaging. It uses radio waves to create a high-resolution image of bones and even soft tissue. Nowadays, most doctors may skip X-rays in favour of MRI because it is much more accurate.
• CT Scan: Alternatively, the doctor may order a CT myelogram, in which the spinal cord is scanned after being injected with a contrast agent.
• Electromyography (EMG): This test can help quantify the severity of nerve compression by measuring the strength of the nerve signal. The severely compressed nerve may produce a weaker electrical impulse.

Although doctors can diagnose sciatica in most cases based on the patient's history and examination, they order the imaging and other tests to rule out other causes. Imaging also helps to pinpoint the location of the nerve compression and helps to understand the cause. For example, after the imaging test, the doctor can say whether the sciatica is the result of bone spurs, a herniated disc, local inflammation, or a tumour.

Although in most cases sciatica can be treated with medication, in a few cases surgery may be necessary.

Prevention is better than treatment

You can reduce your risk of sciatica by making certain lifestyle changes. In most people, sciatica occurs because the lower back muscles cannot cope with the strain. Regular exercises to strengthen the lower back and abdomen can help prevent sciatica.

Sciatica often occurs after lifting heavy objects, and the main cause is poor posture during physical activity. Maintaining the correct position when sitting, lying down and doing physical activities can help prevent sciatica.

Finally, learn the correct way to lift bulky objects without putting undue strain on your lower back. Try to lift things with your back straight and bend your knees instead. Most importantly, avoid lifting and twisting at the same time.