What is Spinal Disc Herniation a.k.a 'Slipped disc'?

Definition 

Disc herniation is a neurological disorder which is characterized by the sliding of nucleus pulposus along the spinal cord and spine, which translates clinically by the appearance of a very intense back pain in that area. This condition occurs when a part or the entire nucleus pulposus herniates through a weakened area of  the fibrous ring of intervertebral disc.

Disc Herniation Patient

Disc herniation is often located posterior and on the same side of the defect. Disc herniation can occur at any level of the intervertebral discs, but the two most common locations are the cervical and the lumbar discs. Lumbar disc herniation is the one that produces most chronic back pain which is radiating into the leg. Lumbar disc herniation is more common than the cervical disc herniation and occurs especially in the segments L5-S1 of the spine, because in this area ligaments are weaker and more slender.

Frequency of disc herniation is relatively high, varying between 1-10% of the adult population. The most affected group of population is between 25-45 years.

Stages of Disc Herniation

Causes

Disc herniation occur when in the fibrous ring, a structure that is surrounding the nucleus pulposus, appear fissures that allows the nucleus pulposus to mobilize from its usual place and reach between vertebral corpus. Then, the nucleus pulposus will reach in the spinal canal and will press on the spinal nerve roots and will cause symptoms.

These fractures occur as a result of trauma, in some professions that require some very intense physical activity or in patients who are sitting very much in the chair. If the patient is compiling of persistent pain, but not a very intense pain, this is a sign of dulling of the intervertebral disc and not a sign of trauma.

Disc Herniation from MRI test

Risk Factor

A very important risk factor in the occurrence of a disc herniation is smoking because it interferes with proper oxygenation of the column and thus of the intervertebral disc. In this way, may appear dehydration and degeneration of the intervertebral disc, which, in time, will cause a disc herniation.

Scientists believe that in the appearance of a disc herniation, an important role is taken by genetic component, especially in patients with lumbar disc herniation.

Other risk factors are represented by:

1. Age;
2. Vigorous physical activity at work;
3. Obesity;
4. Sedentary lifestyle;
5. Excessive vibration on which is subjected the spine column;
6. Birth defects of the spine and spinal canal.

Most hernias occur in the lower back. This location is 15 times more common than the neck and is one of the most common causes of back pain. Cervical disc herniation appear in 8% of cases and in 1-2% of the cases appear high thoracic disc herniation. Cervical hernias occur mostly in the C5 – C6 and C6 – C7 segments of the spine and most often, in this type of disc herniation are involved cervical and brachial plexus.

In some disc herniation are affected the nerve roots and the clinical picture is important and more violent, because the patient will presenting symptoms of both motor and sensitive nature.
Disc herniation affects mostly middle-aged population and young adults with active occupations.

Symptoms

Symptoms are greatly depending on the exact location of the disc herniation and on the soft tissue involved and affected. The pain felt by the patient can vary from moderate to very intense and can radiate along the nerve tracts. Often, disc herniation is not diagnosed immediately, because patients delay the presentation to the doctor or the symptoms are non-specific.
Sometimes, patients with disc herniation are asymptomatic and this situation is possible if the nucleus pulposus is not pressing on the soft tissue or on the nerves.

Symptoms of lumbar disc herniation:

The most common location of lumbar disc herniation is between L4 – L5 or between L5 – S1 segments of the spine. In this case, the most important symptom is the pain, which can affect the lower lumbar area, buttocks, thighs and may radiate to the leg and foot. Of all the nerves, the most often involved is the sciatic nerve, which is causing classic clinical appearance of the pain, but the femoral nerve may be also affected.

Symptoms described by patients include:

1. Muscle spasm;
2. Hypotrophy and muscular atrophy in the affected territory;
3. Pain which is irradiating along nerves track;
4. Pain which become worse when the patient is coughing, sneezing, laughing, because this actions are increasing the pressure in the spinal canal;
5. Paresthesia and other sensory disturbances in the leg.

Here are several characteristics of the pain from a disc herniation:

• Is unilateral;
• The pain has a continuous character, not a pulsating character;
• Appears when the patient is adopting a specific position.

Diagnosis

The diagnosis of a disc herniation can be made sometimes, only by the symptoms if the intensity and nature of the pain are high. Complete history of the patient have to be centered on the character of the pain and its evolution in time and physical examination can highlight disturbances in neurological reflexes, muscle strength and sensory disturbances.

Some characters of the pain may suggest a disc herniation:

• Pain that is localized to the lumbar region and gluteal areas (buttock) is often associated with disc herniation;
• Pain associated with sciatic radiculopathy, which radiates along the leg, below the knee;
• Pain that appear on flexion, rotation of the leg or in prolonged standing and have a sharp character is suggestive of a disc herniation.

Other information suggestive for the diagnosis of disc herniation are:

1. Acute onset of the symptoms, usually after a traumatism;
2. Pain that is  localized unilateral, which is aggravated by movement and relieved by resting in a certain position.

From the patient’s medical history is important to know if there have been recent trauma, if the patient have a profession that is requiring intense physical activity or if in his family exist other members with this condition.

Physical examination may reveal:

1. Reduced physiological curvature of the spine in the area that is involved in the disease process;
2. Abnormal position of the patient;
3. Pain in the leg that appeare after the patient lift the leg as high as he can.

Also, can be performed a series of specific tests that may suggest cervical and lumbar radiculopathy. For example, the patient is asked to tilt the head forward and then to the sides while the doctor applies a slight pressure on top of the head. If the patient will experience pain or any sensory change in this test, the patient is suspected of cervical radiculopathy.There are several tests that can be practiced for the discovery of lumbar radiculopathy.

For a certain diagnosis of disc herniation are indicated imaging studies like, X-rays, computer tomography (CT), magnetic resonance imaging (MRI) and myelography.

X-ray of the spine is especially indicated to exclude other diseases which may have symptoms like disc herniation. The most common diseases that enter in the differential diagnosis are: pelvic fractures, horse tail syndrome, spinal infection, epidural and subdural infections, spinal stenosis and spondylolisthesis. Radiographic examination is limited, because it can not offer useful information about the state of the soft tissue that is surrounding the spine.

Computer tomography (CT) can provide useful information about the diameter of the spinal canal and about the soft tissue that is surrounding the spine.

Magnetic resonance imaging (MRI) is more indicated than CT in diagnosing pathologies of the spine, because has a greater accuracy. Three-dimensional images are obtained and in this way are very well visualized both spine and nerve roots, the nucleus pulposus and it can be determine the degree of the condition. Currently, MRI is the imaging method of first intention for diagnosing disc herniation and can be used even in patients without clinical symptoms. Studies have shown that over 60% of asymptomatic patients who did an MRI, have some degree of disc herniation.

Myelography is a very accurate paraclinical examination, which can reveal the diagnosis of disc herniation, but is an invasive technique, because is requiring a lumbar puncture and the injection of a contrast substance. After the injection of contrast agents is made a radiography of the spinal canal and depending on the aspect can be determine if there are processes that are applying pressure on spinal nerves, if there are hernias and what is their degrees, if there are other pathological processes of the spine. Myelography has better results when is combined with CT.

Other specific tests are the electromyogram (EMG) and tests that determine the conduction velocity of a nerve impulses. EMG is done to determine exactly the nerve root that is involved in disc herniation. EMG can be performed simultaneously with tests that determine the conduction velocity of a nerve impulses and purpose of the two methods is to determine if there is an active pathological process which is affecting the nerves, the nerve roots or the muscles.

In general, patients with symptoms that are suggestive for disc herniation do not require further investigation. But if the patients are elderly, have symptoms that are not improving at the administration of a correct treatment and the pain is atypical, the specialst may request some laboratory tests, like: complete blood count, erythrocyte sedimentation rate (ESR), the level of alkaline phosphatase, serum calcium level and serum protein electrophoresis.

Treatment:

The goal of disc herniation treatment is pain relief and stop the evolution of etiopathogenic process. For this is indicated a period of rest, administration of NSAIDs and physiotherapy. Most patients respond well to these combined treatments and they can resume their daily activities, because the symptoms are adequately controlled. There are a relatively small percentage of patients who need long-term treatment, corticosteroids or even surgery.

Pharmacologic treatment

Pharmacological treatment includes the use of general analgesics or opioids, of muscle relaxants and anti-inflammatory drugs. The goal of pharmacological treatment is to reduce local pain and inflammation and restoring the patient’s freedom of movement.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are mainly indicated for moderate pain relief. Among NSAID, ibuprofen is best, if the patient has no contraindications. It is administrated 200-400 mg, but not exceeding 2 or 3 grams / day. Is not indicated in patients with peptic ulcer, renal failure and coagulation disorders.

Besides ibuprofen can be used other analgesics such as ketoprofen, naproxen or acetaminophen. Acetaminophen is not an NSAID, it has a different mechanism of action and has no side effects so important as NSAIDs (in particular on the stomach) but it has no anti-inflammatory activity. Opioid analgesics can be administered to patients with severe pain that can not be controlled by analgesics. The administration of opioid medication must be done under medical supervision because exist the risk of addiction. Unlike treatment with NSAIDs that can be administrated for a long period of time, opioids are administered only in short periods. Their indications are limited, like a disc herniation which is secondary to a severe trauma.

Muscle relaxants are given only if the patient has muscle spasms. Some patients may receive, corticosteroids (oral or intravenous) if the inflammation is important and it can not be reduced by the treatment with NSAIDs.

Epidural cortisone injections

A therapeutic option used to control pain and inflammation in disc herniation is represented by the injection of corticosteroids into the affected area. The beneficial effects are lasting several months. The procedure has some risks because it is invasive.  For a good localization of the affected area, the injections are performed under radiological control.

Surgical treatment:

Surgery is rarely used for uncomplicated disc herniation. Surgery should be considered as a measure of treatment, only if symptoms persist and are greatly affecting patient’s quality of life, by limiting daily activities and movements.

The most used and indicated surgical procedures are:

1. Discectomy and micro-discectomy represents the removal of a disc that is protruding. The procedure is performed under general anesthesia and the patient remains hospitalized 3-4 days or until health status will allow discharge. To avoid the risk of blood clots, patients are stimulated to mobilize even in the first day, postoperative. Full recovery takes several weeks. If the disc herniation was not unique or whether there are other disorders that have to be treated, recovery will be difficult and longer. Micro-discectomy represents the removal of a fragment of disc which is involved in very small hernia, through a small incision;
2. Laminectomy and hemi-laminectomy, involves to relieve spinal stenosis or nerve compression;
3. Chemonucleolysis, is a procedure that involves injecting an enzyme (chimopapain) inside the herniated disc in order to dissolve the gelatinous substance (nucleus pulposus) that is responsible for the symptoms. In some cases chemonucleolysis can be an alternative to discectomy.