Sciatica: Definition, Causes, Symptoms, Diagnosis, and Treatment

Sciatica is a set of symptoms caused by irritation or compression of the sciatic nerve. The sciatic nerve is the longest and largest nerve in the body, and it runs from the lower back, through the buttocks, and down the legs to the feet. Symptoms of sciatica can include pain that radiates along the path of the sciatic nerve, numbness or tingling in the affected leg, and weakness in the leg muscles. Treatment for sciatica may include over-the-counter or prescription pain medication, physical therapy, and in some cases, surgery.

What is Sciatica?

Sciatica is a set of symptoms caused by irritation or compression of the sciatic nerve, which is the longest and largest nerve in the body. It runs from the lower back, through the buttocks, and down the legs to the feet. Sciatica typically affects only one side of the body and can cause a range of symptoms, including pain, numbness, tingling, and weakness in the leg muscles.

Image of sciatic nerve being compressed
Image of sciatic nerve being compressed

Causes of Sciatica

Sciatica can be caused by any process that may compress the sciatic nerve. Some potential causes are:

  1. Herniated disc: A herniated disc occurs when the soft, gel-like center of a spinal disc bulges out and presses on the sciatic nerve.
  2. Spinal stenosis: Spinal stenosis is the narrowing of the spinal canal, which can put pressure on the sciatic nerve.
  3. Pregnancy: The weight of a growing baby can put extra strain on the lower back and cause the spine to become misaligned, leading to sciatica.
  4. Obesity: Excess weight can put extra strain on the lower back and cause the spine to become misaligned, leading to sciatica.
  5. Prolonged sitting: Sitting for extended periods of time, especially in an uncomfortable position, can cause the muscles in the lower back and buttocks to become tense and fatigued, leading to sciatica.

Other less common causes of sciatica include spinal tumors, infections, and inflammatory conditions like lupus or rheumatoid arthritis.

Incidence

The incidence of sciatica varies depending on the population being studied and the definition of sciatica being used. Studies have estimated lifetime prevalence with figures varying from 12.2% to 43%

Other studies have shown that the prevalence of sciatica was higher in men than in women and that it was more common in people with a history of low back pain.

Symptoms of Sciatica

The symptoms of sciatica can vary widely in severity and duration, and they may include:

  1. Pain: The most common symptom of sciatica is pain that radiates along the path of the sciatic nerve. This pain can range from a dull ache to a sharp, shooting sensation, and it is often made worse by activities like standing, sitting, or walking.
  2. Numbness or tingling: Some people with sciatica may experience numbness or tingling in the affected leg.
  3. Weakness: Sciatica can cause weakness in the leg muscles, making it difficult to move the leg or foot.
  4. Difficulty standing or walking: Severe sciatica can make it difficult to stand or walk, as the pain may be too intense.

The severity of the symptoms can vary widely, from mild discomfort to severe pain that makes it difficult to stand or walk. Symptoms may come and go, or they may be constant. In some cases, symptoms may be mild at first and then become more severe over time.

Diagnosis

Sciatica is typically diagnosed based on a combination of the patient’s medical history, a physical examination, and imaging tests.

History and Physical Examination

During the medical history, the healthcare provider will ask the patient about the location, intensity, and duration of the pain, as well as any other symptoms the patient may be experiencing. The healthcare provider will also ask about the patient’s medical history, including any previous injuries or conditions that may be relevant to the diagnosis.

The physical examination will typically involve the healthcare provider examining the patient’s back, legs, and feet, as well as performing a series of movements to assess the patient’s range of motion and strength. The healthcare provider may also check the patient’s reflexes and sensation in the affected leg.

Imaging Studies

Imaging studies are often used to help diagnose sciatica and determine the cause of the symptoms. The most common imaging studies used to diagnose sciatica include:

  1. X-rays: X-rays are a type of radiation that can pass through the body, producing an image of the bones on film. X-rays can help the healthcare provider identify any problems with the bones in the spine, such as fractures or degeneration.
  2. CT (computed tomography) scan: A CT scan uses X-rays and a computer to produce detailed cross-sectional images of the body. CT scans can help the healthcare provider identify problems with the bones and certain soft tissues in the spine
  3. MRI (magnetic resonance imaging): MRI uses a powerful magnet and radio waves to produce detailed images of the soft tissues in the body, including the muscles, tendons, and ligaments. MRI can help the healthcare provider identify problems with the soft tissues in the spine, such as a herniated disc or spinal stenosis.

It is important to note that the specific imaging studies used to diagnose sciatica will depend on the individual patient and the healthcare provider’s assessment of the patient’s needs and circumstances.

Sciatica Treatment

The treatment for sciatica will depend on the underlying cause of the symptoms and the severity of the pain. Some common treatments for sciatica include:

  1. Medication: Pain medication, such as nonsteroidal anti-inflammatory drugs (NSAIDs), can help reduce inflammation and pain. In some cases, the healthcare provider may prescribe stronger pain medication, such as opioids, for more severe pain.
  2. Physical therapy: Physical therapy can help stretch and strengthen the muscles in the lower back and buttocks, which can help alleviate pressure on the sciatic nerve and reduce pain.
  3. Chiropractic care: Chiropractic care, such as spinal manipulation therapy, involves manual adjustments to the spine to help alleviate pressure on the sciatic nerve and reduce pain.
  4. Acupuncture: Acupuncture involves the insertion of thin needles into specific points on the body to help alleviate pain and promote healing.
  5. Surgery: In some cases, surgery may be necessary to remove the source of the pressure on the sciatic nerve, such as a herniated disc or bone spur.

It is important to work with a healthcare provider to determine the most appropriate treatment for sciatica, as the specific treatment will depend on the individual patient and the underlying cause of the symptoms.

Sources

Koes, B W et al. “Diagnosis and treatment of sciatica.” BMJ (Clinical research ed.) vol. 334,7607 (2007): 1313-7. doi:10.1136/bmj.39223.428495.BE

Tarulli, Andrew W, and Elizabeth M Raynor. “Lumbosacral radiculopathy.” Neurologic clinics vol. 25,2 (2007): 387-405. doi:10.1016/j.ncl.2007.01.008

Deyo, R A, and J N Weinstein. “Low back pain.” The New England journal of medicine vol. 344,5 (2001): 363-70. doi:10.1056/NEJM200102013440508

Konstantinou, Kika, and Kate M Dunn. “Sciatica: review of epidemiological studies and prevalence estimates.” Spine vol. 33,22 (2008): 2464-72. doi:10.1097/BRS.0b013e318183a4a2

About the Author

Dave Harrison, MD

Dr. Harrison is a board certified Emergency Physician with a part time appointment at San Francisco General Medical Center and is an Assistant Clinical Professor-Volunteer at the UCSF School of Medicine. Dr. Harrison attended medical school at Tufts University and completed his Emergency Medicine residency at the University of Southern California. Dr. Harrison manages the editorial process for SpineInfo.com.