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Sciatica

Overview

Sciatica refers to leg pain that is felt along the distribution of the sciatic nerve. The sciatic nerve is the longest and widest nerve of the body that originates in the spinal cord nerve roots L4-S2 (in your backbone), one on both sides, travels along the hip, all the way to the foot. It supplies the skin on the sides of the legs and full feet and the muscles on the back of your thighs and the legs. So the conditions, irritating or compressing the nerve anywhere from its origin in the back up to the feet, can cause pain that could be severe, shooting, or dull, aching with or without sensory changes and weakness, felt in the legs and feet, usually, on one side of the body.

Sciatica can be caused by Spinal disc herniation, spinal stenosis, pelvic tumors, pregnancy, Spondylolisthesis, etc. It is treated by medicines, physiotherapy, eradicating the underlying causes and changes in posture and lifestyle. The pain usually subsides within a few weeks, but further investigations or surgery may be required for prolonged cases, accompanied by signs of serious underlying diseases or loss of bowel and bladder control. 

Causes

Your spinal cord is protected and enclosed by the vertebral column, also known as a backbone or spine, which consists of a series of segmented bones, called vertebrae, separated by intervertebral discs. The nerves originating from the spinal cord make their way through the passages made by the segmented vertebra. The vertebra and the intervertebral discs can be subjected to wear and tear, resulting n the compression of the nerves. The diseases involving the vertebral column can cause sciatica and include the following;

  • Spinal disc herniation (herniation of intervertebral disc compressing the nerves) (90% of cases)
  • Bony spurs (bony outgrowths from vertebra)
  • Spinal stenosis (narrowing of the spinal cavity)
  • Tumors of the spinal cord
  • Inflammations, Infections, or abscesses involving the spinal cord
  • Cauda equina syndrome
  • Trauma to the spine
  • Pregnancy (mechanical pressure)
  • Diabetes 

Risk Factors

Having one or more of the following risk factors may increase your chances of having sciatica.

  • Obesity 
  • Occupations involving lifting heavy weight objects 
  • Physical sports with weightlifting 
  • Prolonged periods of sitting
  • Smoking
  • Increasing age, 
  • Being male, 
  • History of low back pain
  • Having chronic diseases like diabetes, osteoporosis, etc

Epidemiology

Sciatica is a very common complaint. Around 1% to 40% of people experience sciatica at some point in their lives. People are most commonly affected between the ages of 40 and 59. It is more prevalent in men than in women. 

Signs And Symptoms

The symptoms of sciatica are as follows;

  • Pain could be moderate to severe—shooting or dull. 
  • Pain can worsen with movements, coughing, sneezing, or prolonged sitting
  • You may feel numbness or pin and needles sensations in the legs
  • Pain may or may not be accompanied by weakness of the legs
  • In severe cases, bladder and/or bowel control is lost

Diagnosis

Your doctor can make a diagnosis based on the history of a radiating pain that starts from your lower spine, is felt through the buttock, and goes down the back of your leg. He will then perform a physical examination, eliciting signs that may point towards sciatica and nerve root irritation or compression.

The most important of these tests is the Straight leg raise test, in which you would be asked to lie down straight on the testbed and raise your leg, one at a time. The doctor may flex the hip and extend the knee. Any of these maneuvers can cause the same pain as that of sciatica. You may also be asked to perform some actions to test for your muscles' strength and pain, like standing on your toes, rising from a squatting position, etc. 

When the pain does not resolve in a few weeks, or there are some alarming signs like fever, weight loss, bladder or bowel control loss, you may be asked to undergo the following tests;

  • X-ray spine: X-ray can show shortening of the vertebral column, bony spurs, etc
  • CT scan of the spine: CT scan can show disc herniations, bony spurs, etc
  • CT myelography: Before taking a CT scan, a contrast dye is injected into your spinal canal. The circulating dye in your spinal cord and the nerves appear white and give a clearer picture.
  • Discography: A  needle is inserted into the specific disc to check the pressure, contrast is injected to visualize the structural abnormality. The development of pain during the procedure also diagnoses the condition. 
  • MRI scan of the spine: MRI scan is very helpful to see the abnormalities or structures affecting the spinal cord.
  • Electromyography (EMG): This test is used to check the response of muscles upon stimulation of the nerves. It can diagnose the pain by stimulating the nerves. 

Differential Diagnosis

The following conditions can present like sciatica and must be ruled out.

  • Spinal epidural abscess
  • Tumors of the spine
  • Proximal diabetic neuropathy
  • Shingles
  • Acute Lyme radiculopathy
  • Myelopathy
  • Peroneal nerve palsy

Treatment

Multiple modalities are used to treat sciatica. It includes the use of pain killers, muscle relaxants,  bed rest or physiotherapy, finding out and treating the underlying cause, losing weight, improving posture and mobility. 

  • Medicines: Pain killers commonly used are paracetamol, NSAIDs like ibuprofen, diclofenac, muscle relaxants like cyclobenzaprine and methocarbamol, gabapentin, opioids, etc. steroid injections can be used directly in the disc to control inflammation.
  • Physical therapy: Once your pain is lessened a bit, your doctor may advise you to consult a physiotherapist who may encourage you to perform specific exercises that may help alleviate your pain. 
  • Treating underlying conditions: if the pain is due to inflammatory conditions or infections, or tumors, then these conditions will be approached separately, and on the treatment of these, your pain will also subside. 
  • Surgery: Extreme cases of pain that are not relieved by other methods may need surgery. Type of Surgery depends on the cause, like disc herniation, bony spur, spinal stenosis, etc.

Prognosis

Pain is relieved in most patients within a few weeks. Some patients may have a relapse of pain. About 39 to 50% of people reported symptoms even after 1 to 4 years. Some people may need surgery for their pain. According to a report, 10% of people require surgery for their pain.

Prevention

Sciatica is a chronic condition. None of the treatments provide a 100% cure. People may still complain of pain even after treatment. We need to know the precipitating factors causing sciatica and adopt important lifestyle changes to prevent it. 

  • It is vital to maintain a correct posture to avoid straining the backbone. 
  • We should avoid lifting heavy weights or call someone for help to share the weight.
  • We should take a balanced diet with proper portions of important nutrients to prevent deficiencies and prevent obesity.
  • We should avoid a sedentary lifestyle and perform regular exercise or walk to strengthen our musculoskeletal system and halt weight gain, as obesity is one of the risk factors for developing sciatica.
  • When suffering from chronic diseases, proper control of the status of the condition should be maintained to avoid complications leading to bone destruction.

Our clinical experts continually monitor the health and medical content posted on CURA4U, and we update our blogs and articles when new information becomes available. Last reviewed by Dr.Saad Zia on May 08, 2023.

References

https://www.bmj.com/content/381/bmj-2022-070730.full

https://www.pennmedicine.org/for-patients-and-visitors/patient-information/conditions-treated-a-to-z/sciatica#:~:text=Definition,a%20medical%20condition%20by%20itself.

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