Spinal disc herniation From Wikipedia, the free encyclopedia Jump to: navigation, search "Slipped disc" redirects

here. For other uses, see Slipped disc (disambiguation) . Spinal disc herniation Classification and external resources A spinal disc herniation demonstrated via MRI. ICD-10 M51.2 ICD-9 722.0-722.2 OMIM 603932 DiseasesDB 6861 MedlinePlus 000442 eMedicine orthoped/138 radio/219 MeSH D007405 A spinal disc herniation (prolapsus disci intervertebralis) is a medical conditi on affecting the spine due to trauma, lifting injuries, or idiopathic, in which a tear in the outer, fibrous ring (annulus fibrosus) of an intervertebral disc ( discus intervertebralis) allows the soft, central portion (nucleus pulposus) to bulge out beyond the damaged outer rings. Tears are almost always postero-latera l in nature owing to the presence of the posterior longitudinal ligament in the spinal canal. This tear in the disc ring may result in the release of inflammato ry chemical mediators which may directly cause severe pain, even in the absence of nerve root compression (see pathophysiology below). Disc herniations are normally a further development of a previously existing dis c "protrusion", a condition in which the outermost layers of the annulus fibrosu s are still intact, but can bulge when the disc is under pressure. In contrast t o a herniation, none of the nucleus pulposus escapes beyond the outer layers. Most minor herniations heal within a few weeks. Anti-inflammatory treatments for pain associated with disc herniation, protrusion, bulge, or disc tear are gener ally effective. Severe herniations may not heal of their own accord and may requ ire surgical intervention. The condition is widely referred to as a slipped disc, but this term is not medi cally accurate as the spinal discs are fixed in position between the vertebrae a nd cannot in fact "slip". Contents 1 2 3 4 Terminology Signs and symptoms Cause Location 4.1 Cervical 4.2 Thoracic 4.3 Lumbar 5 Pathophysiology 6 Diagnosis 6.1 Physical examination 6.2 Imaging 6.3 Differential diagnosis 7 Treatment 7.1 Lumbar 7.1.1 Indicated 7.1.2 Contraindicated 7.1.3 Inconclusive 7.1.4 Surgical

7.1.5 Surgical options 8 Complications 9 Epidemiology 10 Research 11 References 12 External links Terminology Normal situation and spinal disc herniation in cervical vertebrae. Some of the terms commonly used to describe the condition include herniated disc , prolapsed disc, ruptured disc and slipped disc. Other phenomena that are close ly related include disc protrusion, pinched nerves, sciatica, disc disease, disc degeneration, degenerative disc disease, and black disc. The popular term slipped disc is a misnomer, as the intervertebral discs are tig htly sandwiched between two vertebrae to which they are attached, and cannot act ually "slip", or even get out of place. The disc is actually grown together with the adjacent vertebrae and can be squeezed, stretched and twisted, all in small degrees. It can also be torn, ripped, herniated, and degenerated, but it cannot "slip".[1] Some authors consider that the term "slipped disc" is harmful, as it leads to an incorrect idea of what has occurred and thus of the likely outcome. [2][3] However, one vertebral body can slip relative to an adjacent vertebral bo dy. This is called spondylolisthesis and can damage the disc between the two ver tebrae. Signs and symptoms Symptoms of a herniated disc can vary depending on the location of the herniatio n and the types of soft tissue that become involved. They can range from little or no pain if the disc is the only tissue injured, to severe and unrelenting nec k or low back pain that will radiate into the regions served by affected nerve r oots that are irritated or impinged by the herniated material. Often, herniated discs are not diagnosed immediately, as the patients come with undefined pains i n the thighs, knees, or feet. Other symptoms may include sensory changes such as numbness, tingling, muscular weakness, paralysis, paresthesia, and affection of reflexes. If the herniated disc is in the lumbar region the patient may also ex perience sciatica due to irritation of one of the nerve roots of the sciatic ner ve. Unlike a pulsating pain or pain that comes and goes, which can be caused by muscle spasm, pain from a herniated disc is usually continuous or at least is co ntinuous in a specific position of the body. It is possible to have a herniated disc without any pain or noticeable symptoms, depending on its location. If the extruded nucleus pulposus material doesn't pr ess on soft tissues or nerves, it may not cause any symptoms. A small-sample stu dy examining the cervical spine in symptom-free volunteers has found focal disc protrusions in 50% of participants, which suggests that a considerable part of t he population can have focal herniated discs in their cervical region that do no t cause noticeable symptoms.[4][5] Typically, symptoms are experienced only on one side of the body. If the prolaps e is very large and presses on the spinal cord or the cauda equina in the lumbar region, affection of both sides of the body may occur, often with serious conse quences. Compression of the cauda equina can cause permanent nerve damage or par alysis. The nerve damage can result in loss of bowel and bladder control as well as sexual dysfunction. See Cauda equina syndrome. Cause Disc herniations can result from general wear and tear, such as when performing jobs that require constant sitting. However, herniations often result from jobs that require lifting. Traumatic injury to lumbar discs commonly occurs when lift

ing while bent at the waist, rather than lifting with the legs while the back is straight. Minor back pain and chronic back tiredness are indicators of general wear and tear that make one susceptible to herniation on the occurrence of a tra umatic event, such as bending to pick up a pencil or falling. When the spine is straight, such as in standing or lying down, internal pressure is equalized on a ll parts of the discs. While sitting or bending to lift, internal pressure on a disc can move from 17 psi (lying down) to over 300 psi (lifting with a rounded b ack).[citation needed] Herniation of the contents of the disc into the spinal canal often occurs when t he anterior side (stomach side) of the disc is compressed while sitting or bendi ng forward, and the contents (nucleus pulposus) get pressed against the tightly stretched and thinned membrane (annulus fibrosis) on the posterior side (back si de) of the disc. The combination of membrane thinning from stretching and increa sed internal pressure (200 to 300 psi) results in the rupture of the confining m embrane. The jelly-like contents of the disc then move into the spinal canal, pr essing against the spinal nerves, thus producing intense and usually disabling p ain and other symptoms.[citation needed] There is also a strong genetic component. Mutation in genes coding for proteins involved in the regulation of the extracellular matrix, such as MMP2 and THBS2, has been demonstrated to contribute to lumbar disc herniation.[6] Location The majority of spinal disc herniation cases occur in lumbar region (95% in L4-L 5 or L5-S1).[7] The second most common site is the cervical region (C5-C6, C6-C7 ). The thoracic region accounts for only 0.15% to 4.0% of cases. Herniations usually occur posterolaterally, where the annulus fibrosis is relati vely thin and is not reinforced by the posterior or anterior longitudinal ligame nt.[7] In the cervical spinal cord, a symptomatic posterolateral herniation betw een two vertebrae will impinge on the nerve which exits the spinal canal between those two vertebrae on that side.[7] So for example, a right posterolateral her niation of the disc between vertebrae C5 and C6 will impinge on the right C6 spi nal nerve. The rest of the spinal cord, however, is oriented differently, so a s ymptomatic posterolateral herniation between two vertebrae will actually impinge on the nerve exiting at the next intervertebral foramen down.[7] So for example , a herniation of the disc between the L5 and S1 vertebrae will impinge on the S 1 spinal nerve, which exits between the S1 and S2 vertebrae. Cervical Cervical disc herniations occur in the neck, most often between the fifth & sixt h (C5/6) and the sixth and seventh (C6/7) cervical vertebral bodies. Symptoms ca n affect the back of the skull, the neck, shoulder girdle, scapula,[8] shoulder, arm, and hand. The nerves of the cervical plexus and brachial plexus can be aff ected.[9] Thoracic Thoracic discs are very stable and herniations in this region are quite rare. He rniation of the uppermost thoracic discs can mimic cervical disc herniations, wh ile herniation of the other discs can mimic lumbar herniations.[10] Lumbar Lumbar disc herniations occur in the lower back, most often between the fourth a nd fifth lumbar vertebral bodies or between the fifth and the sacrum. Symptoms c an affect the lower back, buttocks, thigh, anal/genital region (via the Perineal nerve), and may radiate into the foot and/or toe. The sciatic nerve is the most commonly affected nerve, causing symptoms of sciatica. The femoral nerve can al so be affected[11] and cause the patient to experience a numb, tingling feeling throughout one or both legs and even feet or even a burning feeling in the hips

and legs. Example of a herniated disc at the L5-S1 in the lumbar spine. Pathophysiology There is now recognition of the importance of chemical radiculitis in the generation of back pain.[12] A primary focus of surgery is to remove pressure or reduce mechan ical compression on a neural element: either the spinal cord, or a nerve root. B ut it is increasingly recognized that back pain, rather than being solely due to compression, may also be due to chemical inflammation.[12][13][14][15] There is evidence that points to a specific inflammatory mediator of this pain.[16][17] This inflammatory molecule, called tumor necrosis factor-alpha (TNF), is release d not only by the herniated disc, but also in cases of disc tear (annular tear), by facet joints, and in spinal stenosis.[12][18][19][20] In addition to causing pain and inflammation, TNF may also contribute to disc degeneration.[21] Diagnosis Diagnosis is made by a practitioner based on the history, symptoms, and physical examination. At some point in the evaluation, tests may be performed to confirm or rule out other causes of symptoms such as spondylolisthesis, degeneration, t umors, metastases and space-occupying lesions, as well as to evaluate the effica cy of potential treatment options. Physical examination Main article: Straight leg raise The Straight leg raise may be positive, as this finding has low specificity; how ever, it has high sensitivity. Thus the finding of a negative SLR sign is import ant in helping to "rule out" the possibility of a lower lumbar disc herniation. A variation is to lift the leg while the patient is sitting.[22] However, this r educes the sensitivity of the test.[23] Imaging X-ray: Although traditional plain X-rays are limited in their ability to ima ge soft tissues such as discs, muscles, and nerves, they are still used to confi rm or exclude other possibilities such as tumors, infections, fractures, etc. In spite of these limitations, X-ray can still play a relatively inexpensive role in confirming the suspicion of the presence of a herniated disc. If a suspicion is thus strengthened, other methods may be used to provide final confirmation. Computed tomography scan (CT or CAT scan): A diagnostic image created after a computer reads x-rays. It can show the shape and size of the spinal canal, its contents, and the structures around it, including soft tissues. However, visual confirmation of a disc herniation can be difficult with a CT. Magnetic resonance imaging (MRI): A diagnostic test that produces three-dime nsional images of body structures using powerful magnets and computer technology . It can show the spinal cord, nerve roots, and surrounding areas, as well as en largement, degeneration, and tumors. It shows soft tissues even better than CAT scans. An MRI performed with a high magnetic field strength usually provides the most conclusive evidence for diagnosis of a disc herniation. T2-weighted images allow for clear visualization of protruded disc material in the spinal canal. Myelogram: An x-ray of the spinal canal following injection of a contrast ma terial into the surrounding cerebrospinal fluid spaces. By revealing displacemen t of the contrast material, it can show the presence of structures that can caus e pressure on the spinal cord or nerves, such as herniated discs, tumors, or bon e spurs. Because it involves the injection of foreign substances, MRI scans are now preferred in most patients. Myelograms still provide excellent outlines of s pace-occupying lesions, especially when combined with CT scanning (CT myelograph y). Electromyogram and Nerve conduction studies (EMG/NCS): These tests measure t he electrical impulse along nerve roots, peripheral nerves, and muscle tissue. T his will indicate whether there is ongoing nerve damage, if the nerves are in a state of healing from a past injury, or whether there is another site of nerve c

ompression. EMG/NCS studies are typically used to pinpoint the sources of nerve dysfunction distal to the spine.