Lumbar Intervertebral Disc Herniation (LDH)

1. What is LDH?

2. What are the risk factors of LDH?

3. What are the clinical manifestations of LDH?

4. How is LDH diagnosed?

5. How is LDH treated?

1.    What is LDH?

LDH refers to a series of symptoms and signs caused by compression and stimulation of nerve root or cauda equina following fibrous ring rupture, nucleus pulposus herniation or degenerative diseases, including a series of pathological changes of lumbar intervertebral joint and its accessory tissues.

LDH is one of the most common causes of back and leg pain.

-Subtyping of LDH

According to the degree of pathological progression, LDH can be divided into 4 subtypes:

1) Lumbar Intervertebral Disc Degeneration: Protrusion of intervertebral disc. Entire fibrous ring of intervertebral disc protrudes evenly outwards, and the protrusion is less than 5mm.

2) Lumbar Intervertebral Disc Prolapse: The intervertebral disc protrudes. Most of the fibrous ring is broken, only the outer fibrous ring remains intact. Nucleus pulposus is confined to the disc, the protrusion was > 5mm, the shape, regular; the surface, smooth; the boundary, clear; the displacement of protrusion, < 2.5mm.

3) Lumbar Intervertebral Disc Extrusion: The intervertebral disc extrudes, the fibrous ring of the intervertebral disc completely fractures, the protrusion of the nucleus pulposus protrudes out of the intervertebral disc, while is constrained by the posterior longitudinal ligament, the shape, not regular; the surface, not smooth; the boundary, not clear; and the displacement of the protrusion>2.5mm.

4) Lumbar Intervertebral Disc Sequestration: The protrusion of the intervertebral disc is free in the spinal canal or connected with a pedicle of the main body.

2.    What are the risk factors of LDH?

1)     Trauma

Acute and frequent lumber sprain is an important risk factor of LDH, since horizontal tear of fibral ring may be easily caused when the spine is under light load and makes speedy twists.

2)     Vocation

Jobs that involves high inner pressure in lumbar intervertebral disc, such as automobile driver, heavy worker and weightlifter, and etc., may easily cause LDH.

3)     Pregnancy

The whole ligament system of women during pregnancy is at a relaxed state, and the relaxation of posterior longitudinal ligament often causes protrusion of intervertebral discs.

4)     Genetic Predisposition

There are reports on family segregation of LDH, and lower incidence rate in Indians, Eskimos and black Africans compared with other races.

5)     Deformity in Lumbosacral Area

Abnormal stress on lower lumbar vertebra can be caused by deformity in lumbosacral area, such as sacralization of lumber vertebra, lumbarization of sacral vertebra, hemivertebra deformity and small joint deformity, and etc., which is also a cause of intervertebral disc injury and therefore LDH incidence.

3.    What are the clinical manifestations of LDH?

Clinical manifestations of LDH include back pain and sciatica (pain in the sciatic nerve), pain in the lower abdomen or at the front of the thigh, limb numbness, intermittent claudication (disability of walking due to crippling of the legs or feet), cauda equina syndrome, muscle paralysis, coldness in affected limbs.

4.    How is LDH diagnosed?

LDH shall diagnosed by a combined evaluation on imaging and clinical manifestations. A diagnosis basing only on imaging results can be misled.

Imaging examination on LDH

1)      X-ray plain film on lumbar vertebra

Some LDH patients may have completely normal X-ray plain film on lumbar vertebra, though some indications on other patients can help diagnose the disease, which include scoliosis (lateral bending) on anteroposterior film and abnormal changes on lateral film.

2)      CT imaging

With CT imaging, both impact of intervertebral disc on nerves and changes in bone structures and ligaments can be observed.

3)      MRI

With MRI can the protrusion form and location in spinal canal of the diseased intervertebral disc be observed.

5.    How is LDH treated?

The majority of LDH can recover with non-operative treatment, including bed rest, massage and traction; epidural injection of glucocorticoids, anesthetics is also often applied, so as NSAIDs and Chinese patent medicine. Non-operative treatment is usually recommended to patients meeting the following criteria: first attack of LDH, or relatively short course of disease, obvious relief after rest, and no serious protrusion observed in imaging.

Some of LDH patients, however, need surgical treatment, who have suffered for more than 3 months or even longer, received limited effect from conservative treatment, and imaging reveals serious pressure of intervertebral disc on nerves or dural sac, and/or also suffer from stenosis of lumbar canal. Applicable surgeries include chemonucleolysis, herniation excision and discectomy, and etc.