Sciatic nerve pain, which is also widely known by the name ‘sciatica’, is a condition whereby the patient feels pain and irritation as the result of nerve compression. It is also known by the clinical moniker ‘sciatic neuritis’. It is a relatively common, chronic condition.
Whenever a nerve is compressed, irritated, or otherwise inflamed, it usually causes an array of symptoms. In many cases, this results in chronic pain radiating from the affected nerve, and might cause other effects such as tingling sensations within the body or on the skin, or a loss of sensation in the affected area.
Sciatic nerve pain is caused by compression of on or more of five spinal nerves that extend through the lower back and gluteal regions. When these nerves become compressed or the areas around them are inflamed, this usually causes radiating pain in the lower back, the buttocks, and depending on which specific nerve is affected, pars of the leg or foot. The nerves affected are either lumbar nerves (L4 or L5), or sacral nerves (S1, S2, S3), or the sciatic nerve. Sciatica is sometimes confused with pseudosciatica, a condition where referred pain is experienced as a result of damage to the lower back’s facet joints, or because of compression of peripheral sections of the nerve due to soft tissue tension.
The extent of the compression of the nerve affects the severity and range of symptoms that are experienced. More extensive cases usually involve pain, but also include numbness, muscle weakness, a ‘pins and needles’ sensation throughout the affected area, and difficulty moving or controlling leg motion. For some people, exposure to cold weather can worsen symptoms.
Usually, sciatic nerve pain is restricted to one side of the body.
It is important to understand that the term sciatica does not describe the actual cause of nerve compression. Instead, sciatica is a term that describes the symptoms present when a sciatic nerve is compressed. The reason for the compression is usually related to a different diagnosis.
Causes of Sciatic Nerve Pain
Sciatic nerve pain is caused by compression of the lumbar, sacral, or sciatic nerves mentioned above. The cause of compression varies greatly. For instance, sciatic nerve pains can be induced by compression of a dorsal nerve root as a result of a spinal disk bulge or spinal disk herniation. Other causes include roughened, enlarged, or misaligned vertebrae, or because of spinal disk degeneration. Sometimes, sciatic nerve pain will dissipate if tears in disks heal.
Sciatica can also be caused by tumors that apply pressure to the nerve as they grow on the spine or nerve roots. Spinal tumors often cause a range of extra symptoms, such as severe back pain that extends outwards to the hips and downwards to the feet, loss of bladder or bowel control, and muscle weakening. Sometimes, trauma to the spine – caused by accidents such as vehicle collisions or workplace accidents – can also induce sciatica.
Lumbar spinal stenosis – where the spinal canal (where the spinal cord runs between vertebrae) narrows and applies pressure to the spinal cord can also result in sciatic nerve pain. This narrowing can be caused by bone spurs, inflammation, or herniated disks.
Some people – about 15% of the population – experience sciatica as the result of the way that their sciatic nerve grew. In these cases, the nerve runs through the muscle tissue known as the piriformis, instead of behind it in the usual fashion. This means that when the piriformis muscle shortens or experiences a spasm, it compresses or strangles the sciatic nerve. Muscle shortening or spasms are usually caused by injury or overuse. This condition is known as piriformis syndrome, but is also called ‘wallet sciatica’, because a wallet placed in the rear pocket will compress the buttocks muscles and the sciatic nerve when it is sat upon.
How is Sciatic Nerve Pain Diagnosed?
Sciatic Nerve Pain
A doctor will survey a patient about their symptoms, perform a physical exam, and engage in neurological testing activities. A commonly used neurological test is the straight leg rising test, which is considered to indicate sciatica if pain in the sciatic nerve is registered when the leg is moved between 30 and 70 degrees of the leg’s normal flexion.
Further testing might be necessary depending on the severity of the condition. Use of computer tomography or MRI (magnetic resonance imaging) can be used to diagnose sciatica. In severe cases, magnetic resonance neurography will be used to diagnose sciatica. Magnetic resonance neurography might be necessary in order to diagnose piriformis syndrome.
How is Sciatic Nerve Pain Treated?
In the case where the sciatic nerve pain is caused by a prolapse of the lumbar disk or a hernia of the lumbar disk, 9 out of 10 cases will resolve themselves over time without clinical treatment. However, if the condition is caused by epidural abscess, tumors, or cauda equine syndrome, then clinical treatment is almost always necessary.
For alleviating symptoms, medications are often prescribed, but the results are often mixed. Many clinical studies have obtained mixed results (or even completely negative results) when tracking the impact of analgesics and anti-inflammatory drugs on pain caused by sciatica. Bear in mind that this does not meant that medication will necessarily always be ineffective. In addition, some doctors prescribe muscle relaxants to alleviate symptoms.
Clinical studies of sciatica patients have also revealed that there is very little difference in outcome between recommendation by doctors to either stay active or to seek prolonged bed rest, and it is unclear whether the use of physical therapy exercises are any more effective than bed rest alone.
Most sciatica that does not dissipate on its own is treated by optional surgical intervention. Though a variety of surgeries are performed, all focus on treating the underlying cause of the condition by alleviating disk herniation. Clinical studies show that in the short term, this is the most effective treatment for pain relief, though very little difference is seen in long-term follow-ups of patients.