Surgical Procedures
LUMBAR MICRODISKECTOMY


1. WHAT IS AN INTERVERTEBRAL DISC?

An intervertebral disk is a kidney shaped structure located between each pair of vertebrae. They are designed to redistribute forces incurred by the spinal column when sitting, standing, or lifting. The normal intervertebral disk is composed of a semi-liquid center (nucleus) surrounded by several layers of fibrous rings (anulus fibrosus). Together they form a self-contained unit.
The intervertebral disk is strong and stable. When an object is lifted, the force is transmitted directly onto the semi-liquid center and then redistributed radially to the outer fibrous rings. As the force is redistributed, the rings resist deformation. It is this combination that enables the disk to act like a shock absorber.

2. WHAT CAUSES A DISK TO RUPTURE OR HERNIATE?

Repetitive bending and twisting and sometimes a single back injury can create a shear stress across the disk. Over time this stress may cause the outer fibrous rings to break down. Gradually, the semi-liquid center will work its way through the outer ring and push on a nerve. This is known as a disk herniation. Herniated disk, ruptured disk, and slipped disk generally mean the same thing.
There are 5 disks in our lower back, located between each pair of vertebrae from L 1 to S 1. The two lowest disks, L4-5 and L5-S1, most commonly rupture. L3-4 occasionally ruptures, whereas L I-2 and L2-3 rarely do so. Depending on the level involved, different nerves may be pinched. Pressure on a nerve may manifest itself in the form of pain, numbness, weakness, tingling, or loss of a reflex. The distribution of symptoms varies depending on which nerve root is involved.

3. WHAT ARE THE MAIN REASONS FOR PERFORMING A MICRODISKECTOMY?

There are some extreme circumstances, such as loss of bowel and bladder function, when immediate surgery is necessary. However, most disk ruptures resolve gradually without surgical intervention. The most common reason to have surgery is to alleviate pain which has not resolved within a reasonable time period. Many people would like to be more active than their pain allows, and this usually persuades them to have surgery.
Research shows that after 1 year of observation, patients who have chosen surgery have better results than patients treated conservatively (Weber, 1983). However, after follow-up periods longer than 4 years, both the surgical and non-surgical groups have similar improvement.
If your pain is mild or moderately tolerable we do not recommend you proceed with surgery. We also feel that numbness, tingling, or the loss of a reflex is not sufficient to indicate surgery is absolutely necessary. There does not appear to be a significant difference in the results of patients with muscle weakness when treated surgically versus those treated non-surgically (Weber, 1983). Therefore, muscle weakness that is not associated with leg pain is usually treated conservatively, as the muscle may eventually gain strength (unless the weakness is profound).
It is important to realize disk surgery is quite effective in relieving pain in the buttocks area and pain that travels down the leg; however, it is not particularly effective in relieving back pain. Back pain is typically treated with aggressive rehabilitation. The primary reason to proceed with surgery is to relieve pain in the buttocks and leg sooner than would be accomplished without surgery.

4. WHAT IS THE CHANCE OF A SUCCESSFUL OUTCOME?

A microdiskectomy is 85%-95% successful in relieving pain in the buttocks and leg. Pain relief is typically quite rapid, although in specific instances, it may take six to eight weeks for the nerve to calm down. If a nerve has been pinched for a long time, the success rate is rarely 100% as there is usually some residual mild tingling, weakness, or pain, all of which are fairly tolerable.

5. WHAT ARE THE LIMITATIONS OF THE PROCEDURE?

Surgery is intended only to remove pressure from a pinched nerve. When a disk ruptures, a hole is created in the outer ring of the disk. During surgery, the surgeon will enlarge this hole to remove any loose material; however, there is no way to repair the hole. Even though surgery is quite effective in getting rid of buttock and leg pain, you are still left with a disk that will usually heal but takes time to do so. Care has to be taken to prevent undue stress to the disk during this healing period to prevent a re-herniation.

6. WHAT HAPPENS DURING SURGERY?

During surgery, you are carefully positioned on a padded frame in a manner which allows the space between your vertebrae to be opened as widely as possible. A small incision is made on your back over the ruptured disk. The muscles are dissected over to the side to allow us to look at the back part of your vertebrae called the lamina. A small amount of bone is trimmed from the lamina to create a space between the two vertebrae. Some ligaments between the vertebrae will also have to be removed. Utilizing a microscope or magnifying loops the nerve is visualized and then retracted towards the middle of the spine. We then enlarge the hole in the disk, where the rupture has occurred, and try to remove any loose fragments or material within the disk space.

7. WHY IS MAGNIFICATION USED?

The microscope or loops allow us to make a smaller incision. It enhances our visualization by magnifying the field and providing better lighting. This is simply a way of making the procedure safer and more reliable. The general principles of the classic open diskectomy remain the same.

8. WHAT ARE THE ALTERNATIVE METHODS FOR TAKING PRESSURE OFF A NERVE?

Chymopapain, suction diskectomies, and laser surgery are alternative methods used to decompress a nerve. These procedures involve the same principle (a probe is put into the disk, and the disk is either chemically dissolved, mechanically suctioned, or destroyed with a laser). The actual nerve is not visualized, nor is the disk fragment removed. These alternative methods are less invasive than a microdiskectomy but they are not as reliable for decompressing a nerve.
We have found that disks which are small enough to be decompressed utilizing one of these procedures are usually the type that tend to resolve themselves without surgical intervention. We believe that if the disk is large enough to require surgery, the nerve should be directly visualized and decompressed by microdiskectomy.

9. WHAT IS THE HOSPITAL STAY LIKE?

You will check into the hospital two hours prior to surgery. Twenty to thirty minutes prior to surgery you will be taken to Preop Holding where you will be interviewed by the anesthesiologist. The surgery will take 1 to 2 hours to complete and afterwards you will be brought to the Recovery Room where you will remain for approximately 1 to 2 hours.
After surgery you should have significantly less leg pain, although, your back will be quite sore. Even though the size of the incision is small, pain should be expected as your muscles were manipulated during the procedure.
We have found that there is a lower incidence of complications if you are mobilized early. You may be able to get out of bed and begin walking four to six hours after you are taken to your room.
Due to the combination of anesthesia and pain medication, you may feel nauseated and have difficulty urinating. A significant number of patients require a catheter in their bladder to enable them to urinate. You may go home once your pain can be controlled with pills, your bowel and bladder are functioning normally, you have minimal nausea, and are able to eat food. Most patients are ready to go home the next day. Occasionally the hospital stay may last longer.

10. WHAT AM I ALLOWED TO DO WHEN I GO HOME?

We generally advise people to take it easy for the first couple of days. You will be able to take care of yourself, go up and down stairs, and move around based on your own comfort level. For the first 6 weeks you should not put any unnecessary stress on your back. We encourage you to start a walking program 3 or 4 days after you are home. You should walk for as long as is tolerable and slow enough so pain does not flare up in your leg. The nerve is generally quite sensitive after surgery and Intermittent leg pain similar to your pre-surgical pain is common. The pain should calm down quickly if you decrease your activity level. A realistic guideline to establish for yourself is to exercise for a total of 1 hour per day, under the guidance of your doctor. The exercise can be done all at once or in multiple, shorter intervals.

11. WHEN CAN I SHOWER?

You can remove the dressing 3 days after your surgery. You should not shower until 10 days after the surgery. This will allow the wound to seal over. Approximately 10-14 days after surgery, you can remove the Steri-Strips from the incision. We recommend you do not take a bath or submerge the wound for three weeks after the surgery.

12. WHEN CAN I RETURN TO WORK?

Each situation is unique and should be discussed with your physician prior to surgery.

13. WHEN DO I START REHABILITATION ?

During the first 6 weeks after surgery the nerve tends to be very sensitive. We do not recommend physical therapy in the beginning of your recovery cycle because it may cause the nerve root to flare up.
Repetitive bending, twisting, lifting, and prolonged sitting are the most common causes of disk herniation. Therefore, we believe in preventing future problems by teaching you how to properly care for your back. A back education program includes developing proper posture and body mechanics, a strengthening and stretching program, and an aerobic exercise program. You should be aware that a long-term exercise rehabilitation program is an important part of your overall recovery process. Each physician has his own approach to rehabilitation. Your physician will prescribe a rehabilitation program based on your specific needs.