- Long periods of sitting/standing
- Forward bending
- Body maneuvers that increase pressure in intervertebral discs
- Characterize the activities leading up to when the symptoms first presented
- Location of the pain
- Associated factors that reduce and worsen the pain
- Medical history
- The way the sciatic nerve runs through the lower body. It starts in the lower lumbar and upper sacral nerve roots. It exits through the pelvis and runs down the back of the thigh to the knee where it branches out into nerves that provide the motor and sensory functions to the legs and feet.
- Non-spinal sciatica causes. Non-spinal causes usually are the result of irritation of the nerve itself. The most common ways to irritate the nerve is compression, traction, or injury.
- Symptoms perceived as sciatica may not be related to the nerve at all. Injury/s to structures close to the nerve, like the hip, can copy symptoms caused by irritation of the nerve.
Hip joint disorders can emulate sciatica symptomsBecause the sciatic nerve is close to the hip joint, an injury to the hip could resemble symptoms of sciatica. Whatever the cause of the hip injury, those with hip pathology often report pain in the groin, upper thigh, and buttocks. The pain gets worse with activity, specifically bending, and rotation of the hip. Leg pain that turns into a limp when walking means that more likely the hip, and not the lower back, is the cause of the leg pain. X-rays and if necessary MRIs of the hip can help in determining if the hip is the cause of leg pain. An example of hip pathology that mimics spine-related sciatica:
Hip OsteoarthritisThis is characterized by the loss of cartilage. This results in the narrowing of the ball and socket joint. Individuals with arthritis of the spine and hip, a doctor could use a steroid injection as a therapeutic providing pain relief and a diagnostic to help identify the root cause/pain generator.
OsteonecrosisThe femoral head can collapse from a lack of blood flow. Risk factors include:
- Alcohol abuse
- Sickle cell disease
- Chronic steroid use
- Femoral neck fracture
- Hip dislocation
Femoroacetabular ImpingementThis can stem from constant abnormal rubbing between the femoral neck and acetabulum from a bone deformity of the femur, or the acetabulum. Hip impingement at the joint can start the onset of arthritis along with tears of the labrum. This is cartilage that surrounds the hip joint and provides stability.
Trochanteric BursitisThere are fluid-filled sacs called bursas/bursae that help decrease friction between the bones, surrounding tendons, and muscles. They are at multiple locations on the body. Bursitis means that the bursa is inflamed and can be quite painful. The greater trochanter is a bony outward bump that extends from the femur. Trochanteric bursitis refers to inflammation of the bursa that separates the greater trochanter with the muscles and tendons of the thigh. Common symptoms are pain on the outside of the thigh that worsens by pressing on the area and can interfere with proper sleep when lying on the affected side.
Femoral Neck Stress FractureIncomplete fracture/s of the femoral neck typically occur in individuals that walk or run long distances regularly like runners and soldiers. The pain is usually focused around the groin and can be subtle when it presents. Walking or running makes the pain worse.
Sacroiliac joints and fracturesThe sacroiliac joints connect the spine to the pelvis. There are two joints, one on either side of the sacrum. While they are relatively immobile, they go through tremendous force doing routine daily activities. Sacroiliac joint pathology that can mimic spine-related sciatica include:
SacroiliitisThis is inflammation of the sacroiliac joints. The pain presents in a slow fashion with no obvious injury or cause. The pain is usually localized to the buttocks and can radiate down the back of the thigh. It is believed to be caused by irritation of the sciatic nerve by the inflammatory molecules in the sacroiliac joint or could present as referred pain from the joint. This is pain that is detected in a location other than the area of the pain generator. The pain reduces with light walking.
Sacral FractureA fracture of the sacrum can occur in those with a weakened bone after a minor injury and without trauma. Risk factors include:
- Advanced age
- Chronic steroid use
- Rheumatoid arthritis
- Vitamin D deficiency.
Trauma-relatedTrauma to the pelvis or thigh can definitely cause sciatica pain and symptoms. With high-energy injuries, it is possible for the nerve roots of the sciatic nerve to get pulled or torn. More common causes include:
- Posterior hip dislocation
- Pelvic fracture
Penetrating traumaIf some sharp object like a tool or shrapnel penetrates any area where the sciatic nerve is, it could cause sciatica by cutting the nerve. Or the object tears the nerve, known as a laceration. Most cases of trauma-induced sciatica result from a mild form of nerve injury known as neuropraxia. This is an injury that temporarily blocks nerve function. Neuropraxia can develop from the shock waves that surround the object as it travels through the tissue.
Benign tumors and metastatic cancerDiscovering cancer during diagnosis for sciatica is rare. Symptoms that increase the possibility of cancer being the cause include:
- Cancer in medical history
- 50 years and older
- Leg pain that goes on through the night
- No relief from lying on the back
- Night sweats
- Unexplained weight loss
- Nerve tumors include neurofibroma and schwannoma
- Surrounding fatty tissue called a lipoma
- Metastases from another source like lung cancer
ShinglesShingles is a painful rash that occurs on one side of the body. It is caused by the varicella-zoster virus, which is the virus that causes chickenpox. The virus can lie dormant in nerve cells for years without causing any symptoms. Older individuals and individuals with underlying conditions in an immunocompromised state can cause the virus to activate. If the virus reactivates around the buttock and thigh, it can feel like sciatica. The presence of a red rash with blisters around the painful area is consistent with shingles.
Childbirth and endometriosisDuring pregnancy, the pelvis can become compressed between the growing baby and the bones in the pelvis. Also, having the hips and knees flexed and supported in stirrups too long can also cause sciatica. However, pregnancy-related sciatica is often temporary. A less common cause that occurs in women is endometriosis. Endometriosis is the growth of tissue somewhere other than the uterus, usually the ovaries and fallopian tubes. In some cases, this tissue can accumulate around the sciatic nerve or the nerve itself. As the tissue responds to the changes taking place during a normal menstrual cycle, recurrent sciatica pain can present.
Vascular diagnosesArteries and veins in the pelvis and lower extremities that have become abnormal can cause sciatica. Either through compression or lack of oxygen from poor blood flow. An aneurysm can happen when the wall of the artery weakens and cannot withstand the pressure of the blood flowing through. This enlarges the artery and in some cases, the artery grows large enough to compress the nerve. Peripheral artery disease can cause sciatica when not enough blood is circulated from the heart to the muscles in the legs. If not enough oxygen is delivered to the muscles, leg pain and numbness can occur. It’s called claudication and is characterized by pain that is aggravated when walking and relieved when standing still. Risk factors for peripheral artery disease include:
- Smokers both current and those who have quit
- High blood pressure
- High cholesterol
Diabetes/high blood sugarDiabetic peripheral neuropathy happens from nerve damage caused by high blood sugar. Nerves that are exposed to chronic high blood sugar can get damaged from the disruption of proper blood flow or from an alteration of the cellular structure of the nerve.
Prescription medsNerve and muscle damage can happen as a side effect from prescription meds. Neuropathy and myopathy can cause symptoms that mimic sciatica brought on by disc herniation. Sometimes, if the medication is no longer taken the symptoms go away. The list of medications include:
- Chemotherapy agents
- Statins medication to help lower cholesterol
Piriformis syndrome and back pocket wallets
Back pocket walletAlso known as wallet neuritis, and wallet sciatica are terms that have been used to describe compression of the sciatic nerve by a heavy/bulky wallet in a back pocket. It is similar to symptoms of piriformis syndrome and presents in the buttocks and the same leg that can get aggravated from sitting. Usually, if the wallet is the sole cause, taking the wallet from the back pocket to another pocket or other storage option often brings pain relief.
Conclusion non-spine related causesWhile the majority of sciatica cases are caused by a back problem, injury, etc. There are various causes outside of the spinal column. Being able to describe the:
- Pain severity
- Associated symptoms
- Factors that aggravate and alleviate the pain