The Disc Herniation

The bones of the spine are called vertebrae. These bones are connected to create a canal that protects the spinal cord. Five of these vertebrae make up the lower back. This area is called lumbar spine.



Vertebrae cross-section view

Other parts of the spine include:
Spinal cord and nerves. These "cables" carrying electric stimulus travel through the spinal canal carrying messages between the brain and muscles.
Intervertebral disks. In between your vertebrae are flexible intervertebral disks. They act as shock absorbers during walking.
The disks are flat and about a 1,2cm thick. They are made up of two components:

• Annulus fibrosus. This is the tough, flexible outer ring of the disk.
• Nucleus pulposus. This is the soft, jelly-substance center of the disk.

A disk begins to herniate when its jelly-substance nucleus pushes against its outer ring due to wear and tear or a sudden injury. This mechanical pressure against the outer ring may cause lower back pain.

Normal disc

Disc herniation

If the disk is degenerated or injured, the center may squeeze all the way through. Once the nucleus tears through the outer ring, pain in the lower back may improve. Sciatic leg pain, however, increases. This is because the nucleus material inflames the spinal nerves. If the pressureis excessive, may cause pain, numbness, or weakness in one or both legs.

Disc bulging irrigates the nerve root causing sciatica

The Cause of Disc Herniation
A herniated disk is related to the natural aging of the spine.In young adults, disks have a high water content. As we get older, our disks begin to dry out and weaken. The disks begin to shrink and the spaces between the vertebrae get narrower. This normal aging process is called disk degeneration.In addition to the gradual wear and tear that comes with aging, other factors can increase the likelihood of a herniated disk. Knowing what puts you at risk for a herniated disk can help you prevent further problems. Men between the ages of 30 and 50 are most likely to have a disk protrusion. Using back muscles to lift heavy objects, instead of legs in a right position, can cause a herniated disk. Lifting with your legs, not your back, may protect your spine.Overweight loadsthe disks further.There are jobs that are physically demanding. Using safe lifting and movement techniques can help protect your back. Regular exercise is fundamental in preventing a herniated disk. Staying seated for long periods is also a problem of deterioration. Smoking also, lessens the oxygen supply to the disk and causes more rapid degeneration.

Clinical Symptoms
Low back pain is the initial symptom. This pain suffermay last for a few days, then improves. Very often it is followed by the onset of leg pain, and numbness. Later,  weakness may be established. The leg pain typically extends below the knee, and often into the foot and ankle. Symptoms may differ among the these:Back pain, leg and/or foot pain (sciatica), numbness or a tingling sensation in the leg, weakness in the leg and /or foot, loss of bladder or bowel control. This may indicate a more serious problem called caudaequina syndrome.

The sensory nerve root distribution in lower limb, according to disc lesion topography.


Physical Examination
The determination of a herniated lumbar disk by your doctor, is extracted after a medical history and proceeding to a physical examination. The diagnosis can be confirmed by a magnetic resonance imaging (MRI) scan.A physical examination should include a neurological examination to detect weakness or sensory loss. To test muscle weakness, the doctor will assess walking onheels and toes. Your thigh, ankle, and toe strength may also be tested. The physician can detect any loss of sensation by checking whether you are numb to light touch in the leg and foot. In addition, your reflexes at the knee and ankle will be tested, and sometimes may be absent.

Illustration showing straight leg lift test.

Straight leg raise (SLR) test. This test is a very accurate predictor of a disk herniation. In this test, you lie on your back and your doctor lifts the affected leg. The knee remains in a straight position. If you feel pain down your leg and below the knee, you test positive for a herniated disk.

Imaging Exam.
To help confirm a diagnosis of herniated disk, the physician mayprescribe a magnetic resonance imaging (MRI) scan. This scan can create clear images of soft tissues like intervertebral disks.


MRI of the lumbar spine

Treatment of a Herniated Disc
In most cases, if a patient’s pain is going to get better it will start to do so within about six weeks. While waiting to see if the symptoms subside on their own, several non-surgical treatments can help alleviate the pain and facilitate long term healing. The most common conservative treatment include: Physical therapyor manipulation, heat and/or ice therapy, non-steroidal anti-inflammatory drugs, oral steroids,an epidural (cortisone) injection. If the pain and other symptoms continue after six weeks, and if the pain is severe, it is reasonable to consider micro-discectomy surgery as an option.

A micro-discectomy is designed to take the pressure off the nerve root and to provide the nerve with a better healing environment. Usually, only the small portion of the disc that is pushing against the nerve root needs to be removed, and the majority of the intervertebral disc remains intact.Using microsurgical techniques and a small incision, a micro-discectomy can usually be done on an outpatient basis or with one overnight stay in the hospital, and most patients can return to work full duty in one to three weeks.With an experienced surgeon, the success rate of this surgery should be about 95%.



Recurrent Disc Herniation
Unfortunately, approximately 10% of patients will experience another disc herniation at the same location. This recurrence is most likely to happen early in the postoperative period (within the first three months), although it can happen years later. Usually a recurrence can be handled with another micro-discectomy.If it recurs multiple times, a lumbar fusion surgery to stop the motion at the disc level and remove all of the disc material may be considered.

Disc collapse and osteophytes formation

Preparation for spinal fusion

Spinal fusion