What is Sciatica
Sciatica (sciatic neuritis) is a set of symptoms including pain that may be caused by general compression or irritation of one of five spinal nerve roots that give rise to each sciatic nerve, or by compression or irritation of the left or right or both sciatic nerves. The pain is felt in the lower back, buttock, or various parts of the leg and foot. In addition to pain, which is sometimes severe, there may be numbness, muscular weakness, pins and needles or tingling and difficulty in moving or controlling the leg. Typically, the symptoms are only felt on one side of the body. Pain can be severe in prolonged exposure to cold weather.
Although sciatica is a relatively common form of low back pain and leg pain, the true meaning of the term is often misunderstood. Sciatica is a set of symptoms rather than a diagnosis for what is irritating the root of the nerve, causing the pain. This point is important, because treatment for sciatica or sciatic symptoms often differs, depending upon the underlying cause of the symptoms and pain levels. Sciatica is also referred to as Lumbar Radiculopathy, which involves compression of the sciatic nerve roots caused by a herniated (torn) or protruding disc in the lower back.
Sciatica is generally caused by the compression of lumbar nerves L3, L4 or L5 or sacral nerves S1, S2, or S3, or by compression of the sciatic nerve itself. When sciatica is caused by compression of a dorsal nerve root (radix) it is considered a lumbar radiculopathy (or radiculitis when accompanied with an inflammatory response). This can occur as a result of a spinal disk bulge or spinal disc herniation (a herniated intervertebral disc), or from roughening, enlarging, or misalignment (spondylolisthesis) of the vertebrae, or as a result ofdegenerated discs that can reduce the diameter of the lateral foramen (natural hole) through which nerve roots exit the spine. The intervertebral discs consist of an annulus fibrosus, which forms a ring surrounding the inner nucleus pulposus. When there is a tear in the annulus fibrosus, the nucleus pulposus (pulp) may extrude through the tear and press against spinal nerves within the spinal cord, cauda equina, or exiting nerve roots, causing inflammation, numbness or excruciating pain. Sciatica due to compression of a nerve root is one of the most common forms of radiculopathy and is often postural caused by, is most often referred pain from damage to facet joints in the lower back and is felt as pain in the lower back and posterior thighs. Pseudosciatic pain can also be caused by compression of peripheral sections of the nerve, usually from soft tissue tension in the piriformis or related muscles.
Sciatica is diagnosed by physical examination, neurological testing and patient history. Generally if a patient reports the typical radiating pain in one leg as well as one or more neurological indications of nerve root tension or neurological deficit, sciatica can be diagnosed.
The most applied diagnostic test is the straight leg rising test, or Lasègue’s sign, which is considered positive if pain in the sciatic nerve is reproduced with between 30 and 70 degrees passive flexion of the straight leg.
Diagnosis of sciatica through imaging can be achieved either with computerized tomography or with magnetic resonance imaging.
When the cause of sciatica is due to a prolapsed or lumbar disc herniation, 90% of disc prolapses resolve with no intervention. Treatment of the underlying cause of the compression is needed in cases of epidural abscess, epidural tumors, and cauda equina syndrome.
Although medications are commonly prescribed for the treatment of sciatica, evidence from clinical trials to guide the use of analgesics to relieve pain and disability is lacking. Research has shown no significant difference between placebos, NSAIDs, analgesics, and muscle relaxants. Evidence is also lacking in use of opioids and compound drugs.
Elective surgery is the main option for unilateral sciatica and focuses on removal of the underlying cause by removing disk herniation and eventually part of the disc. In a controlled study, surgical intervention was found to have better results after one year but after four and ten year follow ups no significant differences were found.
Moderate quality evidence suggests that spinal manipulation is effective for the treatment of acute sciatica; however, only low level evidence was found to support spinal manipulation for the treatment of chronic sciatica.