What is a herniated disc?

Good postural hygiene, drug treatment, and physical therapy usually work well with a herniated disc. Surgery is indicated in patients with disabling pain that is resistant to treatment.

Disc herniation is the most common neurosurgical pathology and is the most common cause of low back pain radiating down to the lower limb. It is estimated that around the fifth decade of life, up to 40% of men have suffered some lumbago, which is a frequent cause of sick leave due to temporary disability. Lumbar disc herniation has an incidence of 2% in the general population.

Between the vertebrae in the intervertebral disc, which serves as a shock absorber, and loses elasticity and the ability to withstand pressure as people age. The disc comprises a central area called the nucleus pulposus and a fibrous ring that surrounds this nucleus.

Why does a herniated disc occur, and what consequences does it have

A hernia occurs when the nucleus pulposus moves posteriorly (disc protrusion) due to the degeneration of the fibrous ring of the intervertebral disc, even leaving the intervertebral space, becoming a free fragment in the spinal canal. This condition is usually associated with vertebral degeneration, physical overexertion or trauma, and is more frequent after 30.

The pain occurs because the herniated disc compresses the nerve elements that pass through the canal, which can cause compression of the root of a nerve (radiculopathy) or compression of the spinal cord (myelopathy).

The spine’s points most prone to suffer this type of injury are the cervical and lumbar regions because they present greater mobility. Specifically between C4 and C6 and between L4-L5 and S1 (C = cervical vertebrae; L = lumbar vertebrae; S = sacral vertebrae). And hernias usually occur laterally since, in the posterior area, there is a ligament (the posterior common vertebral ligament) that is strong and prevents posterior herniations.

Fortunately, there is no spinal cord but nerve roots at this level, so the damage is not spinal but root, with less serious consequences from a neurological point of view. In the case of cervical hernias, spinal damage can generate more relevant problems.

Causes of a herniated disc

The causes of the appearance of a herniated disc can be diverse, although they are generally associated with the abnormal effort that usually involves carrying out an excessive load:

  • The main cause of herniated disc is overexertion, with more or less load. Certain professions can predispose to this situation, such as those that force repeated and continuous loads of weight ( removals, food and drink delivery people, handling of people with limited mobility, etc.).
  • Repeated movements with more or less large loads in which the back suffers.
  • Situations such as obesity or pregnancy. The increase in body weight of whatever causes overloads in the lumbar area triggers deviations of the spine and greater pressure on the intervertebral discs, giving rise to protrusions or hernias or aggravating those that previously existed.
  • Repeated or sudden flexion or extension of the spine. This is common to find in some sports activities.
  • It is a more frequent pathology in men, perhaps due to their physical disposition to carry heavy material or more abrupt activities.
  • The highest incidence between 30 and 50 years of age translates into an age range where the causes previously described can occur, especially sudden movements and heavy loads. In the case of women, since it is currently the most frequent reproductive age. Even though there is a degenerative component over the years, these factors are not lavished in advanced ages.
  • Vibrations Certain activities that involve repeated body vibrations can predispose to this condition.

Also, it must be taken into account that they can occur in patients with previous pathologies in the spine that favor the protrusion or exit of the nucleus through the disc.

Symptoms of a herniated disc

The initial symptoms of a herniated disc may be low back pain (pain in the lower back) and pain on percussion, along with other symptoms such as contracture of the muscles adjacent to the spine; Furthermore, this pain typically increases with flexion of the spine and when standing and usually improves when lying down.

Among the symptoms of herniated discs, it is also common for the pain to radiate to the lower limb (what is called sciatica ) following the path of the root that is being compressed. Pain is typically reproduced with exploratory maneuvers:

  • The Lasèguemaneuver: passive elevation of the extended leg with the patient lying on his back and is positive if pain appears with an angle of fewer than 60 degrees.
  • The Bragardmaneuver: it is the same as the Lasèguemaneuver, but also with dorsiflexion carried out by mobilizing the foot by the explorer.

Both maneuvers fundamentally stretch the L5 and S1 roots, the most typical lumbar disc herniation area.

However, for L2 to L4, they are:

  • Inverted lasègue: lifting the inverted straight leg, with the patient lying face down.
  • Lasègue cruzado: the elevation of one leg causes pain in another (on that side is where the injury is).


The patient may present sensory alterations (hypoesthesia, paresthesia) or reflex alteration and, although to a lesser extent. Motor deficits may also appear in the territory corresponding to the path of the compressed nerve root.

The typical manifestations of the involvement of each root in posterolateral hernias are:

  • Herniated disc L1-L2 (root L2): pain or alteration of sensation in the thigh’s anterior aspect, with weakness to flex the hip.
  • L2-L3 disc herniation (L3 root): pain or alteration of sensation in the thigh and knee anterior aspect, with weakness in hip flexion and knee extension.
  • L3-L4 herniated disc (L4 root): pain or altered sensation in the thigh, knee, and inner leg. There may be an absence of the patellar reflex (leg extension by gently striking the patellar tendon while the leg hangs at right angles to the thigh) and difficulty extending the knee, with atrophy quadriceps.
  • L4-L5 disc herniation (L5 root): pain in the posterolateral aspect of the thigh and lateral aspect of the leg up to the foot and first toe’s dorsum. There is decreased force for dorsiflexion of the foot and first toe.
  • Herniated disc L5-S1 (root S1): pain radiating from the posterior aspect of the thigh and leg to the sole and lateral edge of the foot and fifth toe, with alterations insensitivity in the same territory. Absence of the Achilles reflex (contraction of the calf muscles when striking the Achilles tendon, producing plantar flexion) and weakness in the foot’s plantar flexion.
  • Cauda equina syndrome . In this situation, the lower limbs’ weakness is appreciated with urinary or fecal incontinence and loss of sensation in the region that would cover a saddle.