Sciatica

– The information has been reviewed by Dr. Ng Hung Kwong, Tommy

Epidemiology

Sciatica is one of the most common types of pain among Hongkongers, though it is important to differentiate between true sciatica and sciatica-like pain. Most patients assume they have sciatica when they experience pain that radiates from their lower back or buttocks to their legs. In fact, these common, sciatica-like symptoms may actually be caused by soft tissue inflammation or other types of chronic pain. As muscle tissue connects from one part of the body to another – for example, lower back muscles extend to the buttocks, while muscles in the buttocks extend to the lower limbs – when there is inflammation, pain may also extend from one part of the body to another, leading patients to believe they are suffering from sciatica. In cases of sciatica-like pain, patients often experience slight pain when they move the affected area, with the pain shifting to different areas as they move. The muscles also tend to relax and the pain may lessen after movement. In addition, sciatica-like pain rarely affects areas below the knee, and generally only occurs behind or at the side of the thigh. As it does not involve compression of the nerves, patients also do not experience numbness or loss of sensation in the feet.

What is Sciatica?

Sciatica is a type of pain that occurs when a herniated disk or bone spur compresses the sciatic nerve, which extends from the lower back to the back of each leg. The pain usually radiates along the path of the sciatic nerve, and because degeneration commonly occurs in the lower two vertebrae, the L5 and S1 spinal nerves are often affected, and the pain may reach the calf or the bottom of the foot. As the condition worsens, nerve function is weakened and the affected muscles may experience numbness or a loss of sensation, impairing movement of the toes and even the person’s ability to walk.

Symptoms

Symptoms of sciatica may last for 24 hours, and may extend to the foot and/or the back of the calf. It is generally difficult to alleviate the pain and the effectiveness of medication is limited. Depending on which nerve is compressed, patients may experience tingling, numbness, or a burning sensation in the leg, while muscle movement may also be affected, e.g., patients may find it difficult to lift the sole of the foot or raise/lower the big toe.

When the lower two vertebrae are compressed during examination, the patient may experience severe pain along the path of the sciatic nerve that extends to the foot.
During a straight leg raise test, which places stress on the sciatic nerve, the pain will intensify and numbness may extend along the sciatic nerve path towards the sole of the foot. This irritates the nerves in the bottom of the foot, affects sensation, and weakens the muscles.
If the S1 nerve is affected, there may be decreased or no response when the Achilles tendon is tapped with a small rubber hammer.

Structural Problems that Cause Sciatica

Herniated disk: patients generally exhibit typical sciatica symptoms, where the pain is steady and often radiates to parts of the body connected to the sciatic nerve. The pain worsens when the patient moves around or sits down due to increased pressure.
Bone spurs or lumbar spinal stenosis: patients experience pain when walking which eases when they sit. This is generally classified as degenerative lumbar stenosis.
Spondylolisthesis (when a vertebra slips out of position)

Risk Factors

Age
Frequent lifting of heavy objects
Previous injury
Pregnancy or being overweight

How is Sciatica Diagnosed?

Medical history and examination: the doctor will check for typical symptoms of sciatica
MRI: the test will reveal any structural issues that may be present in and around the lower back area

Treatment

Physical Therapy

If the sciatica is caused by a herniated disk that is producing only mild symptoms, the doctor may recommend treatment through a combination of medication and physical therapy. The patient’s body may be able to produce enzymes and white blood cells that naturally resolve the herniation and alleviate symptoms within a few weeks.

Surgery

If symptoms do not improve during the monitoring period, or if damage to the nerve is too severe, the doctor may recommend surgery. Minimally invasive lumbar discectomy, where part of the damaged spinal disk is removed to relieve pressure on the affected nerve, involves a small incision and less postoperative pain compared to traditional surgery. Most patients are discharged the day after surgery.

If nerve compression is a result of spinal instability such as spondylolisthesis, the doctor may recommend minimally invasive spine surgery to relieve pressure on the nerve, where rods may also need to be inserted to stabilize the spine. The minimally invasive approach facilitates a quicker recovery, but as the affected joints are not fully restored, the patient will need to undergo physical therapy and exercise appropriately after surgery.

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