About Disc Herniation
Herniation of an intervertebral disc’s contents may result from the stretching of or a tear in the annulus fibrosus. Disc material then may enter the spinal canal or neuroforamen resulting in symptoms. Disc herniations occur in the cervical spine (neck), the thoracic spine, or in the lumbar spine (lower back).
Symptoms: In lower back lumbar disc herniation, pain and/or numbness follows the irritated nerve root, typically down the back of the leg, side of the calf, and possibly into the side of the foot. For this reason, a herniated lumbar disc characteristically produces sciatica but not back pain. Impairment of motor function of the root will cause weakness in raising and lowering the ankle or big toe, depending on the particular nerve root. Very large disc herniations may result in urinary difficulty and constipation.
In cervical disc herniation, the spinal cord as well as the nerve roots may be compressed. The symptoms and signs produced are the result of nerve root compression, spinal cord compression, or both. The most common complaint is neck pain and limited neck motion. Pain also may radiate into the arm, in a pattern characteristic of the particular root involved. In most cases, pain begins upon waking up.
Thoracic disc herniation presents most commonly as chest pain or spine pain, and occasionally in numbness, weakness, or spasticity. Radicular symptoms occur but are more difficult to discern due to the overlapping dermatomal distribution of nerve roots. If the disc herniation compresses the spinal cord, may result.
Diagnosis: The radiographic evaluation of a suspected spine disorder begins with a plain x-ray. A herniated disc, being composed of soft tissue rather than bone, will not be seen on x-ray; however, other associated changes may be seen, such as the characteristic bony ridges of cervical spondylosis. In addition, the alignment can be accurately assessed. MRI has in most cases become the study of choice in disc herniation. Its superior resolution of soft tissues gives good definition of disc material, cord compression, and root compression. When bony detail is required, a myelogram/CT should be obtained. It is more invasive than MRI and may produce effects such as headache, but in some cases may be essential in defining the anatomy.
Treatment: Bed rest and non-steroidal medications often produce relief of acute forms. When symptoms worsen or fail to improve, a surgical procedure called discectomy is indicated. Lumbar disc herniations can often be treated by minimally invasive discectomy techniques. Surgery should also be considered when there is significant compression of the spinal cord with signs of cord dysfunction. Surgery for thoracic disc herniation is more difficult because of anterior approaches; however there are several options, and there has been great success in endoscopic (minimally invasive) removal of thoracic discs. This approach is less invasive than the open thoracic approach. Minimally invasive techniques are now available for many situations requiring disc surgery.
For more information about spine related conditions and treatments, visit the UCLA Spine Center at at spinecenter.ucla.edu.
