Discectomy

A discectomy is the surgery performed to remove a herniated disc from the spinal canal. When a disc herniation occurs, a fragment of the spinal disc is dislodged. This fragment may be pressing against the spinal cord or against the nerve roots that exit (motor nerve root) or enter (sensory nerve root) the spinal cord, causing symptoms of a herniated disc. A discectomy removes this fragment.

The traditional surgery is an open discectomy: the surgeon makes a small incision which enables him or her to directly see the disc and the nerve root that is compressed. The disc is removed with magnification aiding the team.

What are the consequences of disc herniation?
An intervertebral disc that has pushed out and bulges beyond its normal confines is called a “slipped disc” or, more correctly, a herniated disc. This may result from wear and tear, or strain, which compresses the spinal discs. The disc's soft filling presses against sensitive nerves from the spinal cord or against the spinal cord itself. It is usually accompanied by acute onset of pain.

If the disc is in the neck region (cervical spine) you would have neck pain. If in the lower back (lumbar spine) you will probably feel pain there. If the nerve root is compressed you will experience nerve root pain which is felt in the region of the supply of that particular nerve, which may be in the arm, trunk or leg. Often it can be quite vague. It is often associated with numbness and parasthesias (unpleasant feeling of pins and needles) in the distribution of the nerve. The pain felt in your leg is often called sciatica. You can also develop weakness in the muscles supplied by that nerve, and even develop loss of bladder or bowel control.

If the disc compresses the spinal cord, one will develop weakness of the muscle below the site of the compression. This may be acute or come on slowly. In the latter case, one develops stiffness, weakness or both. The gait may be affected and it would feel as though one's balance has been affected.

Most disc herniations will heal over time. There are special reasons why an operation is required:

Why would you require a discectomy?

• Failure of conservative (non operative) treatment to resolve pain,
• The presence of significant signs of nerve damage, like a paralysis of foot movement, or
• Incapacitating pain not relieved by analgesics.

How is a discectomy performed?
In an open discectomy, the surgeon uses a small incision and operates on the disc under a microscope or with other forms of magnification, in order to remove the disc and relieve the pressure. This procedure is performed under general anesthesia.

Taking the size of the patient, the extent and site of the herniation and other factors into account, the discectomy takes 1-2 hours.

If the disc is in the neck region, most operations will be done via a small incision in the front of the neck, but some may be done using an incision in the back of the neck.
If it is in the lower back, almost all operations are done at the back and you will be positioned lying on your stomach.

Cervical discectomy:
A small incision is made in the front of the neck, usually in one the skin creases. The muscles of the neck are easily parted and the blood vessels, air pipe and swallowing tube are retracted. The disc between two vertebrae is then opened, and all disc material removed in order to see the spinal cord and nerve roots at that level. One can then, using fine dissectors, remove disc fragments off the spinal nerve/cord.

In most cases a graft will be placed between the vertebrae in the space where the disc has been removed. Graft material may be synthetic, metal, cadaver or your own bone, harvested from your iliac bone (hip region). Your surgeon will discuss this with you before the operation.

Lumbar discectomy:
The incision – usually about 3cm in length, though it may be longer depending on your size – is centred over the area of the herniated disc. After dissecting the muscles away from the bone of the spine, the surgeon will remove a small amount of bone and ligament from the back of the spine. This part of the procedure is called a laminotomy.

Once the bone and ligament are removed, the surgeon can see, and protect, the spinal nerves. Once the disc herniation is found, the fragment is removed. Depending on the appearance and the condition of the remaining disc, the surgeon may remove more disc fragments in order to avoid another fragment of disc from herniating in the future. Once the disc has been cleaned out from the area around the nerves, the incision will be closed and a dressing applied.

Recovery
Upon awakening after surgery, patients often find that the procedure has completely resolved any leg pain; however, it is not unusual for symptoms to take several weeks to dissipate. Pain around the incision is common, but can usually be controlled with oral pain medications. You may be required to stay anything between two to five days in hospital, depending on your recovery rate. A lumbar brace may help with some symptoms of pain, but it is not necessary in all cases.

Gentle activities such as sitting up and walking are encouraged after surgery, but patients must avoid lifting heavy objects, and should try not to bend or twist the back excessively. Strenuous activity or exercise should be avoided until cleared by the doctor.

Complications

The most common complication is a chance that another fragment of disc will herniate and cause similar symptoms later on. This is a so-called recurrent disc herniation, and the risk of this is about 10 to 15 percent.

Most patients find that a discectomy provides relief of much, if not all, of their symptoms. However, it should be noted that the success of the procedure is about 85-90 percent, meaning that 10 percent of patients who undergo a discectomy will still have persistent symptoms. Patients who have symptoms for long periods of time, or severe neurologic deficits (such as significant weakness) are at higher risk of incomplete recovery.

Other complications include:

• spinal fluid leaks
• bleeding
• infection

All of these can usually be treated, but they may require a longer hospitalisation or
additional surgery.

(Health24, March 2008)