What is sciatica?
The word sciatica comes from sciatic which refers to the largest nerve in the body that runs from the lower back at the level of the lumbar vertebra 3. It is about 2cm wide. It starts from the lumbosacral plexus and goes down to exit the pelvis through the greater sciatic foramen.
The sciatic nerve branches into two to supply each of the limbs. Some of the areas the nerve offer motor functions include:
- Posterior compartment of the thigh muscles that include biceps femoris
- Calf muscles through the tibial nerve
- Inner and outer sides of the leg through the fibular nerve
The sensory functions of the nerve are indirect through its end-point branches.
The area that the sciatic nerve supplies is where symptoms occur when the nerve has issues.
One of the commonest problems that can occur with this nerve is sciatica. This term is used in reference to a collection of symptoms that affect the leg and does not refer to a specific diagnosis.
A more technical name for sciatica is radiculopathy
In most cases, sciatica does not affect both branches running down the legs but only one side. The pain can be severe and activity limiting but in most cases it resolves on its own after a few weeks. When the symptoms are severe, medical or surgical intervention may be necessary.
Symptoms of sciatica
The symptoms relate to the path the nerve takes. Common ones include:
- Lower back pains
- Pain that radiates down the hip, buttock and down the leg
- Tingling or numbness of the affected limb
- Leg weakness and in severe cases, walking is difficult or impossible
The nature of the pain varies. For some people it feels like an electric shock while for others it can be mild and dull. Common actions that may exacerbate sciatica pain include:
- Sitting for long
- Standing for long
Severe types of sciatica can cause disturbance in the bladder and bowel habits. This can either be retention or incontinence. When this happens, it is considered a surgical emergency that must be managed without any delay.
How do you differentiate sciatica from other types of back pain?
According to the American chiropractic association – ACA, at any one time, there are 31 million Americans suffering from some type of back pain. Obviously not all these people have sciatica.
The main difference that separate sciatica from other causes of back pain is the associated properties of the pain. The pain in sciatica runs down the leg to the foot while that of common back pain does not.
Sciatica also usually occurs suddenly without any apparent cause while with other types of back pain; there may be a history of straining or overextending the back.
What causes sciatica?
Sciatica symptoms may follow an injury to the spine, an infection or a malignant process. The commonest cause is a slipped disc which is also referred to as prolapsed or herniated disc. This condition occurs when for some reason the tough tissue between the vertebral bones is damaged and subsequently presses on the sciatic nerve. Sometimes, despite the most advanced investigations, no obvious cause of sciatica can be established.
Other causes of sciatica
- The outlet of the nerve from the spine narrows. This is called spinal stenosis. This leads to the compression of the sciatic nerve
- Injury. When this happens, either the nerve itself or the spine vertebral column is affected
- inflammation of the sacroiliac joint
- Cancerous or benign growths within the spine. If due to cancer, the cause may be from the site or as a metastasis from another part of the body.
- A rare condition called cauda equine syndrome. This serious disorder follows spinal cord nerve damage due to compression.
- Vertebral slip from its normal position. This is not the same as slipped disc where the problem is within the strong rubber-like tissue that lies between the boney vertebrae. This condition is also called spondylolisthesis. Here, either due to an injury or other problems, the vertebra moves forwards or backwards from the normal anatomical place.
- Metabolic disorders that can lead sciatica include complications of diabetes
- Piriformis syndrome. This is a muscle that runs deep in the buttock and very close to the sciatic nerve. Should this muscle get problems or goes into spasms, it presses on the nerve which can give rise to sciatica symptoms due to irritation. A common cause of piriformis is the habit of putting a wallet in the back trouser pocket.
- Any irritation from the adjacent structures can lead to sciatica. This includes bleeding
Risk factors for sciatica
Factors that increase the risk for sciatica include:
- Pregnancy. The increased abdominal pressure and spine curvature are responsible for this.
- Hormonal changes are also thought to contribute to this risk.
Obesity. As in pregnancy, the spine is strained and the excess body weight makes this worse.
- Sedentary lifestyle. This involves prolonged sitting or just lying around.
- An active lifestyle can also increase the risk for sciatica. This includes people who run and walk regularly. The repeated muscle activity can cause irritation of the nerve and subsequent sciatica symptoms.
- Age. Advancing age leads to changes in the spine and increases the risk for problems that include herniated discs and other spinal disorders
- Diabetes. Nerve damage is possible when diabetes is long-standing and the blood sugar control is poor.
- Spinal or pelvis injuries
- Spine congenital disorders
- Occupation. Jobs that require prolonged sitting or moving heavy loads may increase sciatica risk.
How is sciatica diagnosed?
History of the illness
An accurate diagnosis of this condition starts with a detailed history of the illness where the doctor (a GP may be the first contact medic to see) delves into how the symptoms started and the progression. A good history details about the site of the pain, the duration, how it radiates, the nature and its intensity. The direction of where the pain radiates to and what makes it worse or offers relief are more of the questions the doctor will want to know the answers to.
Finally he will want to know whether there is any associated tingling, burning or numbness on any or both of the lower limbs.
What does a thorough physical examination involve? The doctor starts examining you from the moment you enter the door to his office. He will observe how you walk in (gait) and the posture you assume. He will also carry out a general examination before focusing his attention on the problem area. He will note how far you can move a limb and if there are any limitations and associated pain.
Your specialist will carry out localized examination of your spine and note if there is any spine curvature or evidence of muscle spasms. This will be followed by a detailed neurological examination. This involves muscle tone and strength as well as the response of certain reflexes and relevant nerve functions. Depending on the findings, your doctor will go to the next step of looking for an accurate diagnosis.
This may involve a combination of the following radiological imaging tests.
- Plain spinal x-ray. This may show any bone growths or misalignment
- Computerized tomography (CT) scans. This shows greater details and pinpoints any pathology more accurately. A contrast media may be injected into the spinal canal and serial scans are taken. This is called computerized tomography myelogram.
- Electromyography (EMG). Here your nerves’ integrity is tested and problems arising from disc herniation or spinal narrowing can be identified.
- Magnetic resonance imaging (MRI). This test gives great details about the boney structure of the spine vertebrae and the surrounding tissues.
Depending on what the doctor has identified through the history, physical examination and radiological tests, specific laboratory tests may be carried out. The aim here is to rule out infections and possible malignancies as possible causes of the sciatica.
Metabolic disorders such as diabetes that increase the risk of the condition should also be ruled out where necessary. Otherwise, where a specific disorder such as a herniated disc has been identified, then laboratory tests add no value to the patient’s management; unless there are comorbidities with the sciatica.
History, physical examination, imaging tests and laboratory investigations are all meant to confirm the exact cause of the symptoms since other spine-related symptoms may be confused with sciatica. This other conditions that may mimic this condition must be ruled out.
Treatment of sciatica
The treatment of sciatica is an individualized affair. It depends on the causative factor(s) and other considerations such as weight, age, pregnancy and other things that may have been identified during the diagnosis.
Preventing sciatica is recommended when possible. It is also cheaper. Some of the steps you can take to achieve this include:
- Leading a healthy lifestyle. This means avoiding risk factors such as smoking, obesity and a sedentary lifestyle.
- Learn to assume a good posture all the time
- Always have a warmup and cooldown session before and after exercising. This should involve stretching.
- Make sure your mattress is neither too soft nor too hard. The heavy body parts such as the shoulders and the hips should be comfortable lying on it.
- Learn how to lift things safely to avoid straining your back.
At home measures
Sciatica pain can resolve on its own. It can also persist so that you are forced to take certain measures to alleviate the pain and discomfort. The steps you can take at home include:
- Taking over-the-counter analgesic medications
- Remaining physically active
- Using warm packs
- Using ice packs
- Massage liniments
- Where possible, remove any risk factors associated with the pain.
These measures may offer gradual improvement and there may be no need to consider any other steps.
When the sciatica pain persists
If this happens, then it’s time to seek professional help. Common measures may include:
- A physical exercise program by your physical therapist. Initially this may be at a health facility but once you have understood the program, then he may allow you to continue at home. Find out if sciatica exercises work
- Massage therapy and spine manipulation techniques as carried out by physiotherapists and alternative and complementary medicine specialists such as osteopaths and chiropractic doctors. Acupuncture, acupressure and other related techniques can also be tried.
- Use of stronger analgesics. Nonsteroidal anti-inflammatory drugs (NSADs) are commonly used.
- For severe pain, narcotic analgesics may be used for a short period to avoid the risk of addiction.
- Use of muscle relaxing medicines
- Intra-thecal injections of analgesic and or anti-inflammatory drugs. Corticosteroids may be used for short periods of time.
- Sciatica can be a source of depression. Psychological support is necessary for some patients and a few may even require antidepressant drugs. Antidepressant drugs such as amitriptyline have also been found to relief nerve pain and so they can be prescribed for that reason even where there is no depression.
- Part of psychological support can include cognitive behavioral therapy (CBT). This helps a patient to have the right attitude towards the pain they are suffering from.
- Gabapentin is a drug that is better known for use by epileptic patients. However, it has been found to possess a positive side-effect by reducing nerve pain. You may ask your doctor about ongoing clinical trials on sciatica. Volunteering for such trials may expose you to therapies that are not yet available to the mainstream medical practice.
Complications of sciatica
- Chronic pain
- Progressive neurological deficiencies on the lower foot
- Bowel/bladder issues
- Psychological problems
When is surgery necessary for sciatica?
Surgery is avoided as much as possible. However, there are situations where it is unavoidable. These include:
- Where the sciatica has led to bladder and or bowel problems – retention or incontinence
- Some cases of spinal stenosis
- Severe neurological deficiencies of the lower limbs
The surgeon will decide on the exact surgical technique to use depending on the nature of sciatica problem.
Prognosis of sciatica
Majority, up to 90%, of sciatica patients will recover without surgery. About half of all cases recover completely within six weeks. A few of the remaining will need surgical intervention to relieve the pain.
Tarulli AW, R. E. (2007). Lumbosacral radiculopathy. Neurologic Clinics, 387-405.
Koes, B. W., van Tulder, M. W., & Peul, W. C. (2007). Diagnosis and treatment of sciatica BMJ : British Medical Journal, 334(7607), 1313–1317.