Definition, Causes and Stages
The discs are shock absorbers between the vertebrae, designed to help the back/ neck stay flexible while resisting forces in many different planes of motion. Each disc has two parts, annulus fibrosis (firm, tough outer layer) and nucleus pulposis (a softer core).
Disc herniation is a condition in which a tear in the annulus fibrosis ring of an intervertebral disc allows the softer nucleus pulposus to bulge out beyond the natural outer rings. Disc herniation is usually due to age-related degeneration of the annulus, although trauma (Fall or MVA), sports, lifting and twisting injuries, or straining have been implicated as well.
Most communal area for herniation is in the back side of the disc (posterolateral) where structurally the weakest (thinnest annulus) is. A tear in the disc annulus fibrosis may result in the release of chemicals causing inflammation, which may directly cause severe pain even in the absence of nerve root compression.
Disc herniation can happen in the neck (cervical), midback (thoracic) or lower back (lumbar) region although neck and lower back are the most common. Disc Herniation has four stages: mildest form is a “Disc Bulge” which is usually not symptomatic unless it has annular tear in which case can potentially cause back pain. “Disc Protrusion” is wider and more prominent version of a bulge that can cause radiating pain known as lumbar or cervical radiculopathy.
“Disc Extrusion” is a larger disc herniation which extends above or below the disc level into the spinal canal or the foramen, where the nerve root exits. Disc extrusion is often associated with nerve root compression, nerve displacement and radiculopathy (sciatica or shooting pain to the arm) . “Disc sequestration” is the last stage of a disc herniation where a fragment of the herniation separates from the main disc. If it is not in contact with a nerve, it may remain symptom free. If the fragment impinges on a nerve, symptoms can be sever pain or weakness or loss of bowel/bladder function.
Acute or chronic low back pain, neck pain, sciatica or cervical radiculopathy are the main complaints of individual with symptomatic herniated disc. Spinal pain associated with lifting, bending, coughing, running and spine movement could be related to HNP. Also, spine pain that travels down one leg or one arm may be due to HNP. The symptoms of disk herniation are among the leading causes of functional incapacity in both sexes and are a common source of chronic disability in the working years.
Diagnosis of disc herniation is based on medical history, physical examination, imaging as well as symptoms as well as circumstance where the pain started. If the first episode is acute and severe, patients often go to the emergency room. Clinical diagnosis is made based on x-rays (Disc space narrowing, end plate changes, spurring), and physical examination. If there is no progressive neurological loss, further care is often deferred to primary care physician and specialist in an outpatient setting.
A spine specialist will have examined the patient and determine proper workup. A thorough physical examination is performed by the spine specialists, which includes range of motion examination, sensory testing, strength testing and evaluation of reflexes. If there is alarming examination finding, recommendation for further workup is made.
The most accurate test to identify disc herniation is an MRI which can show stages of disc herniation. Some patients are unable to have an MRI in which case a CT and EMG test or a myelogram will help make a diagnosis.
Prevention is the best medicine. A healthy lifestyle not only improves symptoms, it can actually slow the degenerative process. General recommendations include exercise (aerobic activities, core strengthening and stretching), maintain a healthy weight, good posture, good sleeping surfaces, don't smoke, drink more water and less alcohol. In managing patients, when there is no progressive neurological signs and symptoms, a simple x-ray is obtained and if there is no unusual finding (acute fractures, lytic lesions and so forth), then the patient is treated by 6 weeks physical therapy, short course of prednisone taper, spine manipulation, soft tissue treatments along with use of nonsteroidal anti-inflammatory and muscle relaxants.
In the acute phase, sometimes mild opioid medication is prescribed to help with sleep and function ( no indication for long-term use ). In most cases, conservative treatment results in substantial improvement in symptoms.
After physical therapy treatment, patient is re-examined to evaluate for any residual deficits or symptoms. If the pain subsides and function fully recovers, patient is discharged with recommendation to continue a home exercise program and observe correct ergonomics. In some patients, the pain and dysfunction is not managed on oral medications or does not improve with physical therapy. The spine physician would then recommend an MRI to determine further treatment options. In such cases, targeted steroid injections (Lumbar epidural injection or Selective Nerve root injection can help reduce the inflammation in the nerve root and help with the recovery. Spine injection may last several weeks to several months. If the symptom returns, such treatment could be repeated.
Automated percutaneous lumbar discectomy is a minimally invasive procedure, used to treat symptoms of a bulging disc or a small herniated disc in the lower back. Percutaneous discectomy is different from a surgical microdiscectomy in my because it’s performed through a tiny needle in the skin instead of an incision. In some types of percutaneous discectomy, an automated suction-cutting device inserted through the needle is used to extract the disc material.
The aim is to decompress the nerves by removing displaced disc material. There is minimal down time associated with this treatment. If epidural injection or selective nerve block results in good but short lives pain relief, percutaneous lumbar discectomy may be a good option before considering more aggressive open incision microdiscectomy. Not every herniated disc can be treated with this method and may provide appropriate relief in properly selected patients with contained lumbar disc herniation.
Careful risk assessment should be done by PCP, spine surgeon and the patient before considering surgery. Most common surgical solution for herniated disc with radiculopathy is microdiscectomy. In cervical spine, discectomy may be combined with cervical fusion (ACDF) in that segment. This may also be the case for large herniated disc in the lumbar spine with associated spondylolisthesis with instability.
Microdiscectomy is often successful in resolving leg pain but there is a probability that back pain ruled persist beyond the discectomy. Microdiscectomy takes a few hours to complete, with a short course of inpatient hospitalization and a few weeks of outpatient rehabilitation after discharge from the hospital. If microdiscectomy is combined with fusion, the recovery is often prolonged.
Video Education: Lumbar Herniated disc