The spine is formed, among other structures, by vertebrae and intervertebral discs. The intervertebral disc acts as a load-bearing structure with two distinct components: the nucleus pulposus, inside, and the fibrous ring in the periphery. Each component has totally different biomechanical properties. The nucleus pulposus functions as a buffer gel, while the fibrous ring functions as a fibrous containment structure. This disk arrangement allows the absorption and dispersion of normal loading forces experienced by the spine. Over the years, the discs age presenting molecular and structural changes that as a whole are called degenerative disc process.
The degeneration of the intervertebral disc is usually asymptomatic and when it generates symptoms, these are, in general, self-limited.
Spinal disc herniation is defined as a localized displacement of the nucleus and fibrous ring beyond its usual location and can compress some nerve root.
What symptoms cause herniated discs?
The symptoms depend on its location (cervical, dorsal or lumbar) and whether or not they compress nerve roots.
-At the cervical level, they can justify headache, cervicalgia (pain at the neck level) and dorsalgia (pain between the scapulae).
-If they compress a nerve root, pain radiates to the shoulder or upper limb, sometimes it reaches the fingers. The location of the irradiated pain depends on the affected root. When both symptoms occur, it is called cervicobrachialgia.
-Sometimes, in addition to pain, the patient may experience a sensation of anaesthesia (hypoaesthesia), tingling (dysesthesia) and loss of strength in the limb (paralysis if the loss of strength is complete and paresis if it is partial).
-Herniation at the dorsal level is less frequent and may justify pain in the irradiated trunk towards the sternum or abdomen.
-Finally, herniated disks at the lumbar level can generate low back pain with or without irradiation to the lower limb (sciatica), sometimes reaching the foot. When both symptoms occur, it is called lumbociatalgia.
-When the hernias are very large or combined with degenerative processes of the spine or with congenitally narrow vertebral canals, they can produce more severe symptoms such as cervical or dorsal myelopathies and at the lumbar level the cauda equina syndrome. In both cases the recommended treatment is surgical.
In the rest of the cases, unless there is paralysis, conservative treatment is usually advised.
How is it diagnosed?
The diagnosis of spinal disc herniation can be reached in two different ways. On the one hand, the doctor may suspect its existence if the symptoms reported by the patient correspond to an acute lumbociatalgia or acute cervicobrachialgia, confirming it with the performance of an MRI. And in other cases, the finding is coincidental, showing its existence in an MRI that has been requested by lumbago or chronic cervicalgia, for example. In patients who cannot have MRIs, a scanner or CT (CT scan) is performed.
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