Sciatica: Causes, diagnosis and how to ease pain

Sciatica is a common condition that involves the sciatica nerve, the large nerve that runs from the lower back all the way down to the feet.

Here, Miss Hui-Ling Kerr, highly renowned consultant spinal surgeon, provides a detailed insight into sciatica. The Gloucester-based specialist discusses causes, diagnosis and treatment, among other important points.

What are the most common causes of sciatica?

Sciatica is a condition caused by the compression or squashing of the nerve roots in the lower lumbar spine. Patients typically experience pain originating in the back that passes down to the back of the leg, which may reach as far as the foot and the toes. Some patients compare the feeling to "an electric shock”, and there may be tingling or numbness in parts of the leg and foot, as well.

The most common cause of sciatica is a disc herniation, also commonly known as a “slipped disc”. However, the term “slipped disc” is a misnomer as the discs don’t slip out of place. Rather, the discs herniate or bulge, or protrude, similarly to what would happen if you squeezed a balloon between your fingers and part of the balloon protruded out.

Another common cause of sciatica includes spinal stenosis, where due to degenerative old age changes, the space available in the spinal canal gets smaller, reducing the capacity of the nerves to function. Patients then suffer leg pain.

There are other less common causes, such as tumours, infection and fractures, that can lead to the same symptoms.

How can they be effectively diagnosed and treated?

A spinal surgeon such as myself diagnoses sciatica by taking a careful history, performing a detailed examination, and then investigating the patient with appropriate imaging – using a magnetic resonance imaging scan (an MRI scan), for example.

An MRI scan is the most common form of cross-sectional imaging used in spinal surgery. It allows surgeons to see within the spinal canal and determine the diagnosis, as well as the level and the side of the compression. All of this information then helps to direct treatment, which can be in the form of observation and physiotherapy, or more invasive treatments such as injections or spinal surgery.

How can patients with chronic sciatica manage their symptoms and prevent future flare-ups?

I often get asked this question by patients in clinic. I myself also suffer bouts of sciatica from time to time.

I would first recommend to look after your general health. This includes:

• Eating a healthy diet.
• Maintaining a healthy body weight.
• Taking part in regular exercise that will help blood flow and healing, and maintain core strength.
• Avoiding smoking.
• Keeping alcohol consumption to a minimum to reduce inflammation and damage to the body’s tissues.
• Avoiding straining on the toilet. Therefore, I recommend a diet high in vegetables to aid nutrition and prevent constipation.
• Keeping hydrated.

If you do get a bout of sciatica, don’t hesitate to take simple painkillers like paracetamol. Adding ibuprofen will also help reduce the pain, but there’s a note of caution for patients who suffer from gastric problems or who have kidney disease because non-steroidal tablets do have side effects. Non-steroidal tablets can also worsen problems like kidney disease if they’re taken for prolonged periods.

Be careful with your posture. Discs tend to herniate in hyperflexion positions, and so, it’s important to protect your posture when you’re suffering with sciatica. Be very careful with bending, lifting and twisting, and try to minimise these activities if you can.

Finally, be aware of red flags, such as:

• Changes in sensation in the saddle or perianal area
• The loss of bladder or bowel sensation
• Incontinence or episodes of incontinence
• Severe pain in both legs
• Weakness in the legs or foot, such as a “foot drop”

These red flags can be signs of cauda equina syndrome, which is a surgical emergency. If you have these symptoms, you should seek medical advice immediately, which can be either through your local Accident and Emergency department or through your GP.

How can doctors balance pain relief with the risk of side effects?

This depends on each patient. Not all patients can take all painkillers; some patients have allergies and intolerances to certain painkillers, while other patients may be on other medications that can interact with certain painkillers and will therefore be advised not to take them. If patients aren’t sure which painkillers they can or can’t have, it’s best that they speak with their GP.

What are the most effective non-surgical treatments for sciatica?

This depends on the cause of the sciatica. However, it’s known that 80 to 90 per cent of patients with disc herniations can make a spontaneous recovery. Therefore, the most common non-surgical treatment is usually time and awaiting the body’s own immune system to clean up the disc herniation, which it eventually resolves. During this process, I normally recommend patients to perform nerve gliding exercises to help stretch out the nerves, as sometimes the nerves can get tethered by scar tissue during the healing process.

Aside from that, oral painkillers ranging from simple paracetamol to stronger painkillers like opiates and neuromodulating drugs such as gabapentin, can be effective.

I also do consider spinal injections, such as a nerve root block, a non-surgical treatment which can be effective in reducing a patient’s sciatica. The duration of pain relief with an injection is variable and related to the patient’s own anatomy and the morphology of the disc herniation.

Miss Hui-Ling Kerr is a highly regarded consultant spinal surgeon with over 15 years’ experience.

If you are living with sciatica, don’t hesitate to book an appointment with Miss Kerr via her Top Doctors profile today to receive expert assessment and treatment.