The Sciatic Nerve and Sciatica

Running from the lower spine to back of the thigh and calf, before ending at the feet, the sciatic nerve is the largest and longest single nerve in the body. Its main function is to supply sensation and strength to the lower leg by connecting the foot and leg muscles to the spinal cord.

Any pain, irritation or neurological symptoms that affect the sciatic nerve is known as sciatica. Sciatica in itself is not an illness, but rather a symptom of an underlying condition that causes nerve compression, such as a herniated disc, lumbar spinal stenosis, spondylolisthesis and degenerative disc disease. Just as a "headache” is a symptom, it could be due to many other underlying causes.

Causes of Sciatica

There are various probable causes of sciatica. Injury, infection, or any other condition that aggravates the sciatic nerve can trigger sciatica. Here are some of the other common causes:

  • Herniated Disk
    A herniated disc or slipped disc happens when the soft cushion-like part of the disc positioned between the vertebrae of the spine slips through the fibrous surrounding envelop (the annulus) and compresses the sciatic nerve root. The discs in between the vertebrae become weaker and are more prone to injury as you age.
  • Spinal Stenosis
    Spinal stenosis is the narrowing of the spinal canal that results in the compression of the sciatic nerve. This can be caused by the natural deterioration and aging of the vertebrae or the result of excessive growth of soft tissue or enlarged facet joints.
  • Isthmic Spondylolisthesis
    Isthmic Spondylolisthesis is a lumbar spinal condition that arises when there's a small fracture or damage on the area known as the "pars" or isthmus that lets one vertebral body to slip ahead on another vertebral body below it. This pinches the sciatic nerve.
  • Piriformis Syndrome
    Piriformis Syndrome occurs when the piriformis muscle inside the deep layer of the buttock contracts and triggers pain. Since the piriformis muscle location is exactly sitting on the sciatic nerve, it can put pressure on the sciatic nerve.
  • Sacroiliitis
    Sacroiliitis can be due to inflammation or injury of the sacroiliac joint/s, which are located in the lower spine and connected to the pelvis. The symptoms can mimic that of a prolapsed disc and through careful examination the doctor can establish that.
  • Spinal Tumours
    A spinal tumour situated in the spinal canal can cause sciatica as the tumour can irritate the sciatic nerve roots.


Symptoms of Sciatica

Sciatica usually shows symptoms that affect the buttocks and legs more than the back. It usually occurs abruptly and may last for a few days or weeks. Here are some possible symptoms of sciatica:

  • Lower back pain from the hip and buttocks down to one leg
  • Numbness of the affected leg or foot
  • Weakening of the calf muscles
  • A tingling/burning sensation or a jolt from the lower back down to the leg or foot

The intensity of pain may vary from mild to severe. Sometimes, coughing, sneezing or long period of sitting may worsen the indications.


Sciatica Diagnosis

Sciatica can already be validated through the symptoms alone, but tests are still needed in order to determine which treatment will alleviate symptoms and treat the underlying condition. Here are some ways on how to diagnose sciatica:

Physical Exam
The doctor will usually ask where the pain is and when/how did it start. For the physical exam, the doctor may ask you to walk on your toes, stand from a squatting position, or even lift your leg in a straight position.

Imaging Tests
This is usually done when the pain is severe. These tests are used to determine the cause of sciatica, and thereby the method of treatment. The imaging tests may include MRI, Spinal X-Ray, CT Scan and Electromyography (EMG), depending on the doctor's examination and suspicion. He will recommend the most appropriate imaging modality.


Risk Factors for Sciatica

Sciatica is mostly experienced by people who are between ages 30 to 50. Women who are pregnant are also prone to sciatica. Here are other risk factors for sciatica:

  • Aging
    Growth-related changes in the spine as you age, ageing/degenerating disc is more prone to rupture.
  • Obesity
    Excessive body weight increases the strain on the spine.
  • Job
    Occupations that involve lifting of heavy loads, bending of the back, and other jobs that involve prolonged periods of sitting.


Sciatica Prevention

Sciatica can recur. However, the risk of sciatica can be reduced or prevented by doing the following:

  • Regular Exercise
    Exercises that help keep your back and core muscles strong. Make sure that you stretch before you exercise to avoid possible injuries.
  • Better Posture Adaptation
    Maintain proper posture whenever you sit or stand. Make sure that you maintain the normal curve of your back.
  • Effective Body Mechanics Practice
    When carrying heavy objects, make sure that you keep your back straight and bend your knees.


Non-Surgical Treatment for Sciatica

Typically, sciatica can be alleviated with a combination of rest and home-based remedies like hot or cold compresses. Over-the-counter pain relievers and nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin and ibuprofen may also be taken to manage mild to moderate pain. For severe sciatica pain, doctors may prescribe stronger muscle relaxants and steroid/anti-inflammatory injections.

Lifestyle modifications are also advised either to alleviate symptoms of sciatica or prevent it altogether. See the [Sciatica Prevention] section above.


Surgical Treatment for Sciatica

Most cases of sciatica pain are usually treated with non-surgical treatments. However, when the symptoms of sciatica worsen, it may require surgical treatment.

There are different surgical treatments for sciatica, depending on its cause and severity:


  • Usually recommended if the cause of sciatica pain is due to a herniated disc.
  • Generally, patients who don’t recover after some non-operative treatment may opt for surgery.
  • A microscope is usually used to perform microdiscectomy, and the incision is usually minimal.


  • Usually recommended if the sciatica pain is due to spinal stenosis.
  • This involves the removal of the lamina – a segment of the vertebrae that is pushing the nerve roots in the spinal canal.


  • In selected cases, some patients may be suitable for this truly minimally invasive procedure, using a small pin-point radiofrequency probe. This is sometimes performed as a day surgery, and the patient does not need to stay overnight at the hospital. However, the doctor will need to first assess the patient’s suitability for the procedure.

Physiotherapy may be recommended afterwards to strengthen the lower back muscles and promote faster recovery.


When to Seek a Spine Surgeon for Sciatica

If symptoms persist even with medication, rest and stretches, medical attention is advised. A thorough assessment of these symptoms can help determine the cause and treatment of sciatica. Seek medical attention at the onset of the following:

  • Severe lower back pain
  • Leg weakness or numbness
  • Lower body pain arose from an injury
  • Bowel or bladder dysfunction

While rare, some cases of sciatica, particularly those accompanied with severe pain and dysfunction, require surgical intervention.



Accredited at all Parkway Group Hospitals, Dr Chua Soo Yong is a well-established orthopaedic and spine surgeon in Singapore who specializes in complex spinal surgery for the treatment of sciatica, lumbar stenosis and herniated discs, among others. His services at Atlas Orthopaedic Group include decompression surgery, spinal fusion and disc replacement. To schedule an appointment with Dr. Chua Soo Yong, call 6262-0555 or email