An annular tear is a disruption in the fibrous, outer part of the intervertebral disc known as the annulus fibrosus. The intervertebral disc separates the vertebral bodies, which are the structural bones that form the spine. As one ages, the annulus fibrosus can develop tears that can progress from the inside out. The inner part of the intervertebral disc, or the center, is called the nucleus pulposus. It is a soft, gelatinous portion of the intervertebral disk that functions like a shock absorber. If the annular tear extends through the entire annulus fibrosus, the nucleus pulposus can leak out and irritate a nearby nerve. This can result in significant pain that can extend down the leg. Annular tears are most frequently seen in the lower back.
Most annular tears occur as the result of ageing. The neck and lower back bear a lot of the weight of the body and by the time most people are in their thirties, degenerative changes in the spine start to progress, including in the intervertebral discs. Intervertebral disks are susceptible to wear and tear as the body ages. Injuries due to trauma from sports, occupations involving manual labor, or auto accidents can result in annular tears as well. Some common sports that cause annular tears include football, weightlifting and gymnastics. Some people are also genetically susceptible to annular tears. Bone spurs are another potential cause.
The symptoms associated with annular tears include localized pain or shooting pain down the arm or leg. The symptoms can often mimic those associated with a bulging or herniated disc. The tear usually does not cause pain unless it extends to the outer third of the annulus fibrosus. This is because the outer one-third of the annulus is highly innervated by pain fibers. If the tear extends to the outer one-third of the annulus, the result can be localized, “discogenic” pain. If the nucleus pulposus leaks out and irritates a nearby nerve, the patient may experience pain traveling, or radiating, down the arm or leg. Muscle weakness and tingling in the arms, hands, legs and feet are also a possibility. Pain is often worse with sitting, bending, lifting or twisting.
The first step in the diagnosis involves a history and physical examination. Tests that can aid in the establishing a diagnosis of annular tear include x-rays, an MRI or CT scan, electrodiagnostic studies and discography. In discography, the physician pressurizes the disc with contrast dye. She or he also does this in the surrounding disks as a comparison. A CT scan is then performed to detect tears that have taken up the contrast dye. Since this technique can potentially worsen the tear, a new study using a contrast called Gadolinium can be used as an alternative. The Gadolinium is injected by vein and migrates to the blood vessels of the annulus fibrosus. An MRI is then performed to detect flow disruption due to scar tissue.
Conservative management includes:
If conservative measures do not offer significant relief, surgery may be a consideration. Surgical options may include minimally invasive procedures that are used to decompress a nerve if that is the cause of the symptoms.