23.MAR.2018 3 MIN READ | 3 MIN READ

Back pain that spreads down your legs is more common than you might think. Dr Mashfiqul Siddiqui, orthopaedic surgeon at Mount Elizabeth Hospital, explains the possible causes and treatments for this condition.

The sciatic nerve is the largest single nerve in the body. It starts in the lower back, running through each buttock and down the back of each leg, with sections spreading into your thighs, calves, feet and toes.

If this nerve is compressed or irritated, it’s not unusual to experience pain, especially when sitting down. You might feel a burning sensation, tingling sensation, or weakness and numbness in your legs. The pain may also sharpen when walking. This is known as sciatica.

More generally, a compressed or irritated nerve is known medically as radiculopathy, but you might have also heard it referred to as a ‘trapped’ or ‘pinched’ nerve.

What causes radiculopathy?

Slipped disc causing radiculopathy
According to Dr Mashfiqul, there are many things that can put pressure on your nerves and result in pain.

“Often, the problem lies in the nerves that are in the spine,” he says. “In younger patients, the cause of nerve compression is usually a slipped disc (when one of the padded discs between your spinal bones protrudes awkwardly). In these patients, the pain usually goes down one leg, correlating with whichever nerve is compressed.

“In older patients, sometimes the spinal bone (vertebra) itself can slip forward, which puts pressure on more than one nerve. These patients may complain of pain going down both calves when they walk, which feels a bit better when they rest.”

When any nerve is compressed, it’s not unusual to feel tingling or numbness. Occasionally, the leg muscles themselves may weaken. In more severe cases, problems with bladder or bowel function may occur.

A malfunctioning nerve may also result in similar symptoms, although this is rare.

When should I go see a doctor?

If you have symptoms of an irritated nerve that are not getting better over time, make sure to visit your doctor for a proper diagnosis. Seek a consultation as soon as possible if your legs feel weak or numb.  

If you are struggling to pass urine, go to the emergency department and seek medical advice immediately.

What will my doctor do to diagnose radiculopathy?

Diagnose radiculopathy with MRI
Often, your doctor will recommend an MRI (magnetic resonance imaging) body scan before making a diagnosis. You’ll need to lie down so the machine can scan your back. This will help your doctor to identify exactly which nerve, or nerves, are compressed in your spine, as well as where they are located and how severe the problem is.   

You may also need to have an x-ray. This is carried out in a standing position, which makes it easier for your doctor to see the alignment of your spine.

If your doctor suspects the nerves themselves are malfunctioning, they may also do a conduction test, which measures how fast electrical impulses travel through your nerves. They will apply 2 small electrode patches to the area, one stimulates the nerve with a mild electrical pulse, and the other records the resulting activity.

How will my doctor treat radiculopathy?

Treatment really depends on what’s causing the pain in your back and legs.

“Common problems such as slipped disc can often be managed with medication and physiotherapy, with simple exercises to relieve pain and improve mobility,” explains Dr Mashfiqul. “Sometimes, steroid injections may also help. If problems persist, your doctor may suggest a microdiscectomy, a minimally invasive surgery to remove the disc through a small cut in the back.

“If one of your bones has moved out of place and is putting pressure on a nerve (known as spondylolisthesis), physical therapy, medications and heat/ice therapy can all help. But if the pain is severe or ongoing, a spinal fusion surgery is generally effective. This joins 2 or more bones together using screws or bone grafts to keep them from moving around.”

If you are diagnosed with a malfunctioning nerve, your doctor will recommend a treatment based on all the factors involved, including its causes and symptoms.

But don’t panic. If you’re experiencing ongoing back and leg pain, it is best to seek a proper diagnosis before considering your options.

Mohammad Mashfiqul Arafin Siddiqui
Orthopaedic Surgeon
Mount Elizabeth Hospital

Dr Mashfiqul Siddiqui is an orthopaedic surgeon practising at Mount Elizabeth Hospital, Singapore, with expertise in complex spinal surgery. His areas of interest include spinal degeneration (in the neck and back), prolapsed intervertebral disc (slipped disc), cervical disc replacement (replacing the discs in the neck), spinal deformity (such as scoliosis) and spinal tumours.