Disc Herniation – Causes, Risk Factors And Symptoms
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 is often located posterior and on the same side of the defect. The intervertebral disc is located between the vertebral bodies. It is designed to absorb the shock waves which are being put on the vertebral column while are performed sudden movements during strenuous activities.
The intervertebral disc is composed of a central area with the consistency of a gel substance, called the nucleus pulposus which is surrounded by a fibrous capsule, called the fibrous ring. This structure is held in place by a strong ligament, called anterior longitudinal ligament (which is located anterior to the spine vertebral bodies) and posterior longitudinal ligament (located posterior to the spine vertebral bodies). Besides these two ligaments, the structures are kept fixed also by the paravertebral muscles.
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.
Spinal column is formed by the overlapping of the vertebrae and has many roles, including to support the trunk, to protect the spinal cord and nerves that emerge from it and which are distribute to the periphery. Despite the fact that it look rigid, spinal column has some flexibility and vertebrae are overlapping through some spaces which are connected by a fibrous rings, which have in the center a very fine viscous gel, called the nucleus pulposus.
The function of fibrous ring is to equal distribute pressure in all area of the spine and not to overload one area of the spine. Thus, are amortized a lot of shock waves. The spine column is divided into several regions: cervical spine, dorsal spine, lumbar spine, sacral spine and coccygial spine.
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.
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:
- Vigorous physical activity at work;
- Sedentary lifestyle;
- Excessive vibration on which is subjected the spine column;
- 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 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:
- Muscle spasm;
- Hypotrophy and muscular atrophy in the affected territory;
- Pain which is irradiating along nerves track;
- Pain which become worse when the patient is coughing, sneezing, laughing, because this actions are increasing the pressure in the spinal canal;
- Paresthesia and other sensory disturbances in the leg.
Symptoms of cervical disc herniation:
Symptoms may be localized to the posterior region of the skull, neck, pectoral arch, shoulder and upper limb and if there exist cervical and brachial plexus damage, the intensity of the pain is increased.
The most common symptoms are:
- Asthenia of the muscles of the upper limbs;
- Intense pain in the shoulder;
- Pain in the nuchal region;
- Failure to turn the head or making sudden movements;
- Pain which is Irradiating in the shoulder, arm, forearm, and rarely in the hand and fingers;
- Spasm of the superior vertebral muscles;
- Sharp pain which appear in laughing, coughing and sneezing.
There 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.