An intervertebral disc is a strong ligament that connects one vertebral bone to the next. The discs are the shock-absorbing cushions between each vertebra of the spine. Each disc has a strong outer ring of fibers, called the annulus fibrosus, and a soft, jelly-like center, called the nucleus pulposus. The annulus is the strongest area of the disc and the ligament that connects each vertebra together. The nucleus, or center of the disc, is hydrated and serves as the main shock absorber. Discs in the spine increase in size from the neck to the low back as there are increasing needs for shock absorption due to weight and gravity. These specific disc ligaments function just like knee ligaments and shoulder ligaments do. They allow the spine to move so we can bend forward, backward and sideways. Just like other ligaments, the discs can be injured.
The annulus can tear or rupture anywhere around the disc. If it tears and no disc material is ruptured, this is called an annular tear and can be extremely painful as the outer fibers carry pain signals. This tear will heal with scar tissue over time but is more prone to future tears and injury. If the annulus tears and the center nucleus can squeeze out, a piece of the disc from the center or outside portion can break off and extend outward. A disc herniation, by definition, is displacement of disc material beyond the normal confines of the disc space. The terms disc protrusion, disc bulge, disc herniation, ruptured disc, and slipped disc all mean the same thing and imply that disc material has left the normal disc space.
If disc material herniates, or squeezes out, this can put pressure on the spinal cord or spinal nerves. This can cause severe pain in the path of the nerve being pinched. Pressure against the nerve root from a herniated disc can cause numbness and weakness along the nerve. When the nerve root is inflamed, the added pressure may also cause vague, deep pain and/or cause sharp, shooting pain to radiate along the pathway of the nerve. There is also evidence that the nucleus pulposus material is quite acidic and causes a chemical irritation of the nerve roots. The consistency of a disc depends upon whether it is the outer tough annular portion or the central soft nuclear portion. In lay terms many compare the consistency of a disc herniation to that of lobster or crab meat.
Specifically, a disc fragment in the neck that pinches a nerve to the arm would cause arm pain, whereas in the low back a piece of disc that breaks off and pinches a lower extremity nerve would cause leg pain. This can also happen in the mid-back and cause pain that wraps around the trunk. Depending upon which nerve is pinched different pain patterns may arise. Classic sciatica, which is pain down the back of the thigh and calf, is usually caused by a herniation at one of the bottom two levels of the spinal canal pinching the L5 and/or S1 nerve and producing pain in that pattern.
Herniated discs are most common in young to middle-aged adults, it rarely occurs in children. A herniated disc may occur when too much force is exerted on an otherwise healthy intervertebral disc. Heavy forces on the neck or low back may simply be too much for even a healthy disc to absorb. For example, falling from a significant height such as a ladder can cause significant force through the spine. If strong enough, a vertebra can break or a disc can rupture. Bending can also place high forces on the discs between each vertebra. If you bend and try to lift a heavy object, the force can cause a disc to rupture.
A disc can also rupture after repeated annular tears that weaken the disc over time. At some point lifting or bending can cause too much pressure across the disc. This activity may have been only a little force and something that years earlier would never had been a problem. This is due to the effects of aging on the spine, or degenerative changes. The natural process of aging causes discs to become weakened from degeneration. Not everyone with a herniated disc has degenerative problems and not everyone with degeneration will suffer from a herniated disc.
A disc herniation can arise from something as simple as poor posture. As postural muscles fatigue, shoulders begin to round forward and the head will also drift forward creating excessive tension on the discs, ligaments, and joints of the cervical spine. Every inch of forward head posture adds an additional 10 pounds of pressure on the spine, that means having your head held in a forward position by 4 inches can add 40 pounds of pull on your cervical spine. Over time, excessive tension causes disc weakness, joint and ligament inflammation, and muscle tightness.
The symptoms of a herniated disc may not include a wide array of pain. The symptoms come from increased pressure and irritation of the nerves. Many people may not have neck or back pain with a herniated disc. Symptoms of a herniated disc usually include pain that travels into one or both arms or legs, numbness or tingling in areas of extremities, muscle weakness, and loss of the reflexes in extremities. Where these symptoms occur depends on where the herniation is located. The location of the symptoms helps determine the diagnosis as nerves usually travel in specific patterns.
A herniated disc may be diagnosed after a complete history and comprehensive physical exam. In addition, several diagnostic tests can be used. Imaging studies at the Virginia Spine Institute are usually a first step in understanding spine pathology. These include standing and bending X-rays to evaluate spinal alignment, stability and disc space height. Your doctor will determine whether additional tests are needed. An MRI is the standard imaging to assess disc and nerve pathology. An EMG may be used to determine which specific nerves are involved and the extent of possible nerve damage.
Treatment of a herniated disc depends on the severity of symptoms and apparent nerve damage. Most disc herniations improve in six weeks to three months from the initial injury. In many cases, medication management and quality physical therapy may be enough to allow your body to heal.
Medications are commonly used to control pain, inflammation, muscle spasm, and sleep disturbance. These may involve steroids, non-steroidal anti-inflammatory drugs (NSAIDs), pain medications, and muscle relaxers to help control symptoms and reduce inflammation. Physical therapy is often prescribed with the goal of assisting in calming pain and inflammation, improving mobility and strength, and helping achieve daily activities with greater ease and ability. Exercises focus on improving core strength, spinal strength, coordination and mobility of the spine. Epidural Steroid Injections (ESI) are usually reserved when other conservative measures do not work, or in an effort to postpone surgery. An ESI places a small amount of ‘cortisone’ into the spinal canal. Cortisone is a strong anti-inflammatory medicine that may decrease nerve inflammation and ease pain caused by irritated nerve roots. This treatment is not always successful but may provide short-term help.
The good news is that when properly identified and treated most patients will improve with non-operative care. For the few where nerve compression remains too much, minimally invasive surgical interventions are usually highly successful in eliminating the symptoms and allowing people to return to a full and active lifestyle. The goal of surgery is to remove the offending disc material and decompress the irritating pressure. Surgery may be recommended if there is unbearable pain non-responsive to medical management, unacceptable or progressive weakness, evidence of spinal cord compression, and/or bowel or bladder concerns.
Our skilled surgeons at Virginia Spine Institute have performed operations to address herniated discs in both the neck and the low back on professional athletes and allowed them to return to sport without limitation or restriction once the tissue is healed. In a minimally invasive microdiscectomy surgery, the remaining disc requires two to three months to heal before returning to elite levels of play. For simple daily activities, patients are usually able to return within a few days of the microsurgical outpatient procedure. Appropriate surgical correction must take into account the patient’s medical and surgical history, existing spine pathology and what symptoms need to be addressed. The surgeons at Virginia Spine Institute tailor every surgical decision making process to each unique patient and their specific disc pathology.