Sciatica is a medical term for pain that radiates along the sciatic nerve. This is the largest nerve in the body and starts in the lower back, then branches through the hips and buttocks before travelling down the back of each leg. Although the sciatic nerve has branches on each side of the body, sciatic pain (when it occurs) tends to affect one side of the body only. The pain needs to be in the distribution of the sciatic nerve, though it does not necessarily need to be due to a sciatic nerve disorder. It has to be felt in the thigh as well as below the knee. If the pain is not felt below the knee, it is not sciatica. Typically, sciatica gets worse with coughing, sneezing, straining or laughing
Since sciatica refers to a type of pain instead of a medical condition, it can have many underlying causes. The most common causes of sciatic nerve pain are a herniated spinal disc, a bone spur on the spine or spinal stenosis. These conditions can pinch nerves in the lower back area, thus causing (sometimes severe) leg pain and inflammation on the affected side of the body. In some cases, the patient can also experience numbness in the affected areas.
Despite the severity of its symptoms in some cases, sciatica can typically be treated using non invasive approaches that do not involve surgery.
However, in some cases, sciatica can cause problems with bowel or bladder control, or severe leg weakness. When these symptoms are present, surgery may be necessary to correct the problem.
The most common cause of sciatica is pinching of the sciatic nerve in the lumbar spine or lower back area. Five sets of paired nerve roots in the lumbar area combine to form the sciatic nerve. Most of the time, sciatica is caused when one of these nerve roots is compressed or irritated.
As mentioned above, this is in turn most commonly a result of:
A herniated spinal disc. This is thought to be the commonest cause;
Overgrowth of the vertebrae that help form the spine, resulting in bone spurs on the spine;
Lumbar spinal stenosis, or a narrowing of the spinal canal through which the sciatic nerve travels;
Spondylolisthesis, where one of the bones (vertebrae) in the spine slips out of place.
In much rarer cases, sciatica can be a result of damage to the sciatic nerve from a tumor or from diabetes.
Sciatica has several risk factors that increase the likelihood of experiencing the condition. These include:
Age – the likelihood of developing conditions like herniated disks or spinal stenosis increases with age, and the risk of developing sciatica therefore increases also;
Excess body weight as well as increased height increase the pressure on the spine and therefore raise the risk of compression of the nerves in the spinal canal.
Occupations that require lots of heavy lifting (especially while bending and twisting) can also increase sciatica risk, especially if the patient uses incorrect technique that places too much of a burden on the spine and not enough on the legs;
Poor posture can also increase the risk of nerve compression, especially among individuals who spend long periods in a seated position (for example while driving)
Smoking and psychological stress
Diabetes results in excess sugar in the blood which can then damage bodily nerves, including the sciatic nerve.
Symptoms Of Sciatica
The main symptoms are:
Pain radiating from the lower back through the buttock and down the back of the leg (usually either the left or right legs but not both). The pain can extend downwards as far as the calf or even to the toes;
The nature of sciatic nerve pain can vary widely from case to case. In some individuals, it can be a dull ache but in others a shooting pain or burning sensation. Some patients report feeling a pain akin to an electric shock;
In some cases, the pain is worse when the patient sneezes or coughs. In (some) other patients, it is worse after a prolonged period in a seated position;
In some patients, sciatic pain is accompanied by numbness or tingling in the affected leg. One part of the leg may be painful while another may experience numbness or tingling;
Muscle weakness in the affected leg is another possible symptom.
The following symptoms should be regarded as possible signs of serious nerve damage:
Loss of sensation or weakness in the affected leg;
Difficulties controlling the bowel (ie faecal incontinence) or bladder function.
Perineal/perianal sensory loss or disturbance (saddle anaesthesia or paraesthesia)
Unexpected laxity of the anal sphincter
(This) The above could be signs of cauda equina syndrome – a serious condition that demands urgent medical attention.
Individuals experiencing these symptoms should see a doctor as soon as possible. Other circumstances that should prompt an immediate medical consultation are if:
Sciatic pain is experienced immediately after suffering a traumatic injury (e.g. following a road accident);
The pain, numbness or weakness appears suddenly and with no prior warning.
Sciatica is most commonly diagnosed via a physical examination of the patient that includes evaluation of his/her reflexes and muscle strength on the affected side of the body.
Some simple tests to identify possible sciatica include:
Walking on your toes or heels;
Rising from a squatting position;
Lying on your back and lifting your legs one at a time.
If you experience pain or symptoms get worse as a result of any or all of these activities, this is a possible indicator of sciatica.
The doctor may also review the patient’s medical history to look for back problems (such as herniated discs) that could cause sciatica.
Doctors may also request imaging studies (X ray, CT scan, MRI or EMG) to look for back problems such as herniated discs or spinal stenosis that may be the cause of the sciatica. MRI is the investigation of choice. It is usually performed in preference to CT scanning because of the high radiation dose associated with the latter. Plain X-rays are not very useful. Often, clinicians would only consider imaging if it is likely to change the management of the patient.
Treatment Of Sciatica
Sciatica is usually a self-limiting condition. A high proportion of patients improve with little or no treatment within about three to four weeks. Therefore, patients can be reassured and advised to try conservative measures in the first instance. They should be advised to remain active and to continue with their normal daily activities.
Home Based Treatments
Hot & Cold Therapy – this may be based on the use of cold packs for the first 2-3 days followed by hot packs. Alternating hot & cold packs (20 minutes each) may be tried if the results are subjectively better;
Sciatica stretches for the lower back can help relieve the pain and other unpleasant symptoms by reducing the pressure on nerve roots;
Pain relief medications such as ibuprofen or naproxen (an NSAID) may be tried for additional relief. Another option is paracetamol, an NSAID or tramadol in combination with codeine.
If the above home based treatments do not provide significant relief, doctors can suggest/prescribe more specialized therapies for sciatica:
Various classes of drugs (anti – inflammatory, muscle relaxants, narcotics and anti seizure medications) can all produce some relief of sciatica symptoms. Doctors should be able to suggest a combination of drugs that may be appropriate for a specific patient;
Physical therapy can also help relieve the symptoms of sciatica. The doctor can refer a sciatica patient to a physical therapist who can devise an exercise program for this purpose. These may include exercises to correct posture, strengthen back muscles and increase flexibility;
Steroid injections into the area around the compressed nerve roots can reduce inflammation and relieve sciatic pain and discomfort.
Patients should be advised to seek medical attention without delay if they develop any signs of cauda equina syndrome (CES). CES requires immediate referral for neurosurgical input.
As a last option, doctors can suggest surgery if the above options do not provide relief. As a general rule of thumb, surgery should be considered if the patient fails to improve after six to eight weeks of conservative treatment. A surgeon can operate to remove the herniated disc or bone spur that may be behind the patient’s sciatica.