Herniated/Prolapsed Intervertebral Disc

Dimitris Papadopoulos MD Fellow Of Interventional Pain Practice (FIPP)

Updated 30 December, 2010


Vertebral bodies are separated one from another with intervertebral discs. The discs are composed of an inner core (nucleus pulposus) and an outer ring (annulus fibrosus), which supports the nucleus. Intervertebral discs are like “cushions” between vertebrae and serve as the spine’s shock absorbing system.
In many cases, intervertebral discs degenerate and lead to a protruded or herniated disc. This occurs most often in the lumbar spine, which receives most of the body’s weight. Degenerative disc disorders are divided in two major categories: with or without ruptured annulus fibrosus.
In case of disc prolapse, the disc protrudes into the spinal canal or intervertebral foramen with the nucleus pulposus remaining intruded into the unruptured annulus fibrosus.
When the disc has herniated, the annulus fibrosus gets ruptured and the nucleus protrudes into the spinal canal or intervetrebal foramen. In a few rare cases, fragments of the ruptured annulus fibrosus scatter within the spinal canal.
The nucleus contains chemical irritants which result  in inflammation and oedema of the nerve root coming out the ipsilateral intervertebral foramen and inhibition of the local venous circulation. As a result, the nerve has much less space to move, is being compressed by the herniation and induces neuropathic radicular pain.
In several cases, the acute or subacute radiculitis (nerve root inflammation) may transform into chronic radiculitis due to the formation of adhesions, which disturb the nerve root and cause a chronic nerve inflammation and dysfunction manifested with pain when sitting and walking, and pain relief when lying down. Adhesions are formed because of the inflammatory chemical substances released by the herniated disc.


The term sciatica describes the symptom of pain starting from the waist, moving downwards to the buttocks and continuing along the sciatic nerve pathway down to the toes.
The pain has a sudden onset, is described as an electric current and burning sensation and may be accompanied with numbness, tingling and slight  weakness of the affected leg muscles. The intensity of the pain ranges from moderate to high.
Sciatica is not a medical diagnosis but a symptom induced by some cause. Acute sciatica is due to a herniated disc. Lumbar herniated discs usually occur at lower levels (L4-L5 and L5-S1) that induce radicular pain (due to nerve root inflammation), following the L5 and S1 dermatome distribution ipsilaterally to the herniated disc.
Pain produced by inflammation of the 5th lumbar nerve root starts from the buttock, radiates along the lateral thigh and extends  all the way down to the big toe . The pain due to inflammation of the 1st sacral nerve root is located in the buttock and radiates all the way from the posterior thigh and knee down to the heel and little toe.


The diagnosis is based on clinical examination, radiological evaluation, CT scan and more specifically MRI and EMG.
MRI provides detailed information on anatomical abnormalities of the spine and is more advantageous than CT scan because it highlights the morphological details of intervertebral discs and nerve roots.
EMG is a slightly painful examination confirming the nerve dysfunction and its degree, as well as locating the spinal level of the defect origin. EMG may also be used prior to surgery, as a reference examination for the postoperative evaluation of the patient’s  outcome.


The pain usually subsides following a conservative treatment with analgesics and anti-inflammatory drugs, in combination with rest during the first week and, later on, with physical therapy and active therapeutic exercises.
Should the symptom persist for longer than 4-6 weeks, this means that there is subacute persisting radiculitis and the patient needs to undergo some minimally invasive pain treatment according  to each individual case (transforaminal epidural injectionRACZ neuroplasty, transcutaneous decompression).

Should the patient develop gradual and continuously aggravating loss of muscle strength or/and urinary/ faecal incontinence or newly occurring urinary/ faecal dysfunction, then and only then the patient has to resort to emergency surgery.
The majority of sciatica cases resulting from herniated disc are successfully treated with conservative or minimally invasive treatment. Only a smal proportion  have to be treated surgically because of the aggravating neurological picture.