The intervertebral disc is responsible for the attachment of vertebral bodies to each other, providing flexibility and absorbing and distributing the loads applied to the spinal column. With aging, the disc undergoes significant changes in volume and shape as well as in biochemical composition and biomechanical properties. Lumbar disc herniations are believed to result from anular degeneration that leads to a weakening of the anulus fibrosus, leaving the disc susceptible to anular fissuring and tearing.

When the soft part between bones in the spine presses on the nerves around the backbone, it's called a herniated disc. The word "herniate" means to bulge or to stick out. Sometimes this is called a ruptured disc.

Herniated discs are most common in the lumbar spine--the part of your backbone between the bottom of your ribs and your hips. Discs are soft "cushions" between the bones of the spine. The drawing to the left shows the spine. The spine holds up your body. It also protects your spinal cord and nerves. The discs in the spine let you move your backbone.

As you grow older, your discs become flatter--less cushiony. If a disc becomes too weak, the outer part may tear. The inside part of the disc pushes through the tear and presses on the nerves beside it. The drawing below shows how a disc looks when it gets pushed through the tear and presses on a nerve. Herniated discs are most common in people in their 30s and 40s.

The low back pain is a result of the injury to the annulus fibrosis. The fissure, or tear, of this structure causes tissue damage that generates prostaglandin release and subsequent inflammation.As the disc extrudes past the annular tear, the disc material begins to impinge on the nerve root adjacent to the disc. The trauma to the annulus may subside when the pressure from the disc is released via the herniation, thus allowing the back pain to diminish. The annulus refers pain to the back, as do the facet joints and vertebral ligaments. If the inflammation remains, then the back pain persists. The paravertebral muscles are brought into this fray. The referred pain to the back causes an increase in the paravertebral muscle tone. This intensified tone may escalate to a point that pain is self-generated. A feedback cycle often ensues which promotes muscle spasm. Any movement will then exacerbate this cycle and worsen the pain.

As the disc protrudes into the confined compartment of the spinal canal, it takes up space. If there is not room, the nerve root will be compressed and will begin to refer pain in its distribution. Further compromise to the nerve root will then promote the development of numbness. Lastly, with additional compression, the nerve will engender weakness of the muscle supplied by that nerve. Understanding these concepts aids in the formulation of a cogent treatment plan.
Diagnosis of low back pain and/or leg pain is based on the patient’s history, physical examination, and imaging studies. Variations from any of these three elements should instigate a wider differential diagnosis. The above history is quite common. However, frequently there is no antecedent factor for disc herniation. The wear and tear on the annulus is sufficient for failure of the “gasket.” Family history of disc disease is universal, but then low back pain is noted in 90% of the population.

Radiculopathy has many common features but variations need to be considered. Groin pain is an example. In addition, high lumbar discs and L5-S1 (sacrum) will produce this discomfort. The most likely regions for referred pain are:
L1-L2 Inguinal Region
L2-L3 Hip, Anterolateral Thigh
L3-L4 Lateral Thigh, Knee, Shin
L4-L5 Posterior Thigh, Lateral Calf, Dorsal Foot
L5-S1 Posterior Thigh, Posterior Calf, Heel

Physical Exam
Numbness or paresthesias will follow the same regions as pain, but variations in the sensory distributions are relatively commonplace. Yet, there are areas for sensation, which are very predictive for radiculopathy. In the lower nerve roots, the last two digits and ball of the foot are associated with a S-1 pattern. L-5 involvement results in numbness at the great toe web space.

Motor function is the last to be compromised by a disc herniation. The more severe the compression on the nerve, the more likely weakness will ensue. Weakness is also a negative indicator for spontaneous recovery. Its presence suggests that decompression will probably be needed. Disc herniations can be localized by loss of motor (muscle) function at the levels noted below:

Deep tendon reflexes are the most objective of the physical findings. The problem is that the L-5 nerve root does not have a reflex to test. L-4 is obviously the patellar reflex and S-1 is the Achilles reflex.
Bowel or bladder incontinence and / or acute weakness are operative emergencies

Imaging of the Herniated Disc
The major finding on plain radiographs of patients with a herniated disc is decreased disc height. Radiographs have limited diagnostic value for herniated disc because degenerative changes are age-related and are equally present in asymptomatic and symptomatic persons. Neurodiagnostic imaging modalities reveal abnormalities in at least one third of asymptomatic patients. For this reason, computed tomography (CT) also has limited diagnostic value for herniated disc.

The gold standard modality for visualizing the herniated disc is magnetic resonance imaging (MRI), which has been reported to be as accurate as CT myelography in the diagnosis of thoracic and lumbar disc herniation. T1-weighted sagittal spin-echo images can confirm disc herniation; however, the size of herniation is underestimated because the low signal of the anulus merges with the low signal of the cerebrospinal fluid. Conventional T2 and T2-weighted fast spin-echo images are used in the diagnosis of degenerative disc disease. MRI also has the ability to demonstrate damage to the intervertebral disc, including anular tears and edema in the adjacent end plates. As with CT scans, MRI can reveal bulging and degenerative discs in asymptomatic persons; therefore, any management decisions should be based on the clinical findings corroborated by diagnostic test results.

MRI has been traditionally used to obtain images in the axial and sagittal planes. Recent advances have brought about oblique images, which provide better views of certain anatomic structures that were not available with conventional methods.13,14 Oblique images are oriented perpendicular to the course of the neural foramen. It has been suggested that oblique MRI be added to the conventional technique to aid in the detection of foraminal impingement.

What can be done for the pain of a herniated disc?
Your doctor may suggest medicine for the pain. You can probably be more active after you take the pain medicine for two days. Becoming active will help you get better faster. If your pain is very bad, your doctor may suggest that you rest in bed for one or two days.

If the pain medicine doesn't help, your doctor may give you a shot in your backbone. This might stop your pain. You may need more than one shot.

Sometimes stretching of the spine, by your doctor or a chiropractor, can help the pain.

What about my posture?
Good posture (standing up straight, sitting straight, lifting things with your back straight) can help your back. Bend your knees and hips when you lift something and keep your back straight. Hold an object close to your body when you carry it. If you stand for a long time, put one foot on a small stool or box for a while. If you sit for a long time, put your feet on a small stool so your knees are higher than your hips. Don't wear high-heeled shoes. Don't sleep on your stomach. These things can put more pressure on your discs. The pictures on this page show good posture in standing and lifting.

Treatment
Medical therapy is best for preserving the natural mechanics of the spine. Unfortunately, some mechanical problems of spine defy healing. The mainstay of medical management is the use of anti-inflammatories. NSAIDs are a good first step as they work to reduce the prostaglandin induced pain and localized swelling. If these medications are not effective, then it is reasonable to consider using steroid therapy. Oral and epidural are the two forms to contemplate. The latter appears to be efficacious approximately 60% of the time. Strategies for scheduling the injections vary, but one injection every two weeks is the norm. The series of injections are probably the top of the pyramid for medical management. If the first injection is not effective, then the remaining injections may not be worthwhile. If the pain returns shortly after the injections, then surgery will probably be required.

If a given NSAID does not work and the pain is tolerable, then changing to a different family of NSAIDs is indicated. Three weeks of therapy with a NSAID is recommended before attempting a shift. The COX2 non-steroidals have been quite effective, and seem to have better compliance due to the lack of GI side effects. Cost has been an issue.

While waiting for the anti-inflammatories to work, analgesics should be available. There is advantage in reducing the pain and making the patient more comfortable. Added benefit is seen when the pain / spasm cycle is broken. Antispasmodic medications are available, but seem to have little effect in the presence of a significant disc problem.

Physical therapy and the modalities of heat, ultrasound, and muscle stimulation offer another level of treatment. The techniques are to reduce the immediate degree of acute discomfort, and to break the pain/spasm cycles. Reconditioning helps to reduce the tendency to generate spasm if the activity does not provoke more localized spinal tissue insult. More to the point, exercise promotes better muscle tone and strength. The spinal muscles will assume more of the burden of weight bearing away from the ligaments and joints, thus assuring better spinal mechanics.

The essence of conservative treatment is to reduce the pain and inflammation. As this process is evolving, the herniated disc is undergoing change, too. The nucleus pulposus has a certain degree of moisture content when it is in the disc space. A herniated disc is exposed to a drier environment and will begin to dehydrate and shrink. If enough shrinkage occurs, then the nerve will be less likely to be pinched and the radicular pain will recede. The inflammation also induces calcium influx into the tissues, which thickens the ligaments and annulus. This overall strengthens the spine by decreasing movement and back pain.

Surgical Indications for Lumbar Disc Herniation
While most patients with a herniated disc may be effectively treated conservatively, some do not respond to conservative treatment or have symptoms that necessitate referral to surgery.

Any surgical decisions should be firmly based on the clinical symptoms and corroborating results of diagnostic testing. Indications for referral include the following: (1) cauda equina syndrome, (2) progressive neurologic deficit, (3) profound neurologic deficit and (4) severe and disabling pain refractory to conservative treatm

The goal of surgery for a lumbar herniated disk is to remove the portion of the disk that is impinging on the nerve root (usually about 5% to 10% of the disk).

Surgery options for a lumbar herniated disk
There are many different options for surgery for herniated disks. Whichever procedure the surgeon uses probably does not matter as much as their comfort level with the procedure, and with their experience. The gold standard for surgery is an open discectomy.