Surgical Procedures
POSTERIOR SPINIAL INSTRUMENTATION & FUSION


1. WHAT IS THE BASIC STRUCTURE OF THE SPINE?

The spine is composed of vertebrae, discs, a spinal cord and nerves. Typically, the vertebrae are referred to as the "spine". These vertebrae are strong and flexible bones that support the trunk and protect the spinal cord and nerves. The disc is the soft structure located between the vertebrae. These discs act as cushions, which enable the vertebrae to move.

2. WHAT IS A LUMBAR FUSION?

A lumbar fusion is when two or more vertebrae in the low back are "fused" together to create a solid bridge of bone between the vertebrae and across the disc space. A fusion is usually performed to eliminate movement between vertebrae and stabilize a painful or unstable segment of the spine. Once a segment of the spine is stabilized the patient usually experiences some relief of pain. Surgery is not recommended unless there is about a 70% chance of improving your level of pain. This improvement does not necessarily mean that you will be completely pain free, but rather that your level of pain should be significantly improved. It means that there is a 25% chance your pain will not really improve. However, each situation is unique. There is also at least a 5% chance that you may become significantly worse.

3. WILL I LOSE MOBILITY ONCE A PORTION OF MY SPINE BECOMES SOLID BONE?

It depends in part on how much of the spine is fused. The spine will not move as much, but you will not notice it. Most people believe that the spine enables you to bend over at the waist; this motion actually occurs mostly at the hips. There are patients that have their entire spine fused yet are still able to touch their fingertips to the floor.

4. WHAT HAPPENS DURING A LUMBAR FUSION?

At the hospital you are given a general anesthetic to put you to sleep. Once you are asleep, padding is placed between your body and the table and you are carefully positioned face down. An incision is made over your lower back and your muscles are gently pulled away from your spine to expose the lumbar vertebrae. If your nerves are under any pressure they are decompressed (fusion is often combined with laminectomy). Once the nerve work is completed the surgeon begins the bone grafting process. This entails removing small pieces of bone from the outside part of the pelvis. These pieces are used to stimulate the fusion. The bone on the lower part of your spine is then roughened up. This enables the bone chips to have a better surface area with which to bond. The graft is then placed closely against the roughened up bony surfaces. It is this combination of small pieces of bone with a raw bony surface, which stimulates the body to form a solid piece of bone (fusion).

5. WHY ARE SCREWS, PLATES, OR RODS USED IN MY SPINE?

Screws, plates, or rods (also known as hardware, implants, or instrumentation) are used to immobilize the spine, which thereby enhances the healing process. Hardware acts as an internal splint. Historically, braces or casts were used. However, research has found that they are not as effective in immobilizing the spine. If too much motion occurs the vertebrae may not fuse together. This is known as a pseudarthrosis or nonunion. The incidence of pseudarthrosis ranges from 15 to 40% without hardware. If this occurs, further surgery may be required to stimulate the bone to fuse. Screws, rods, and plates have been shown to significantly decrease the rate of nonunion.
Once the fusion process is completed, it is the fusion that holds the spine stable, not the hardware. Therefore, if the fusion is solid the hardware really serves no purpose, but we do not recommend the routine removal of the hardware as that would require an additional operation with no benefit to the patient. If the fusion is not solid, there is a high probability that the hardware will loosen or break. This is not dangerous and will not cause nerve damage as the hardware is buried deep within the fusion mass, similar to steel rods buried in concrete for reinforcement.

The benefits of the screws, rods and plates are as follows:
1. They help correct deformity of the spine.
2. They give immediate stability and earlier relief of pain.
3. They give rise to a higher fusion rate than non-instrumented fusions.

6. WHAT ARE THE RISKS OF USING SCREWS, RODS, OR PLATES IN MY SPINE?

Complications associated with placement of the screws include dural tear, bone breakage, nerve damage, vascular injury, and infection. If the fusion does not get solid then the screws or rods may loosen or break.

7. DOES SMOKING HAVE AN EFFECT ON THE OUTCOME OF MY FUSION?

Research shows that the healing rate is greater than 90% in non-smokers and less than 50% in smokers. Many surgeons frown on performing a fusion in patients who smoke because of the higher rate of non-union and infection. Physicians have also found that in smokers it is sometimes necessary to go in through the front and the back of your spine in order to obtain a successful fusion. If you smoke or use tobacco, please discuss this in detail with your physician.

8. WHAT WILL THE HOSPITAL STAY BE LIKE?

Several nurses and doctors will ask you questions regarding your medical history. It would be helpful to bring a list of medications (doses and frequency) that you are currently using. You will wait in the holding area of the operating room for about 30 minutes before surgery. This is where you will meet your anesthesiologist. After surgery you will wake up in the Recovery Area where you will remain for 1 to 2 hours. There will be a catheter in your bladder. The catheter is usually removed on the 2nd day, however, if you are unable to urinate you may need to be re-catheterized. Due to the anesthesia and medications, many patients have a poor recollection of this time period. The first 2 days will be difficult. The most painful part of recovery is usually the site of the bone graft. In order to obtain an adequate amount of graft the gluteal muscles have to be dissected. As you walk these muscles will pull on the graft site. This area will be painful until the scar matures, which may take 6 weeks.
We will try very hard to keep you as comfortable as possible with IV narcotics. You will be able to control the amount of pain medication you receive by using a small push button (PCA). You can push the button as often as you need; the machine will control the dose. We have been very happy with the amount of pain control we can obtain with this machine. The combination of narcotics, anesthesia, and spine surgery may cause you to experience some nausea. We allow only ice chips or small amounts of liquids until you are passing gas. If fed too soon, you may become distended and even more nauseated. About 20% of our patients are fairly nauseated within the first 24 hours. This problem is usually resolved by the second or third day. We encourage you to get out of bed on the first or second day. By the third day we insist that you are ambulating. We have found that there is a lower incidence of lung, bladder, and vascular complications the earlier the patient is mobilized.

9. WHEN CAN I SHOWER?

The drains are usually removed from your back on the second day. You may
shower 10 days after the surgery when the wound has sealed. You should not swim or take a bath for 3 weeks after surgery. There are small tapes on your skin that you will need to pull off after 10-14 days. The sutures do not need to be removed as they will eventually be absorbed into the skin. If your wound is closed with staples, they should be removed around 2 weeks after the surgery by the clinic nurse.

10. WHEN CAN I GO HOME, AND WHAT WILL I BE ABLE TO DO?

You may go home once your pain can be controlled with pills, your incision is not
draining, and your bowel and bladder are functioning normally. Most patients are ready to go home by the 3rd or 4th day after surgery. Within the first few weeks, we encourage you to begin walking for one half-hour to two hours each day. If you were given a brace, you must wear it during the day although you can remove it to sleep or shower. You should be able to go up and down stairs, and perform basic daily activities without too much of a problem. You may drive when you have the strength to perform a panic stop and are not taking narcotic medicines that may impair your judgment. You should avoid bending at the waist, as that increases the stress across the fusion site. It usually takes a minimum of three to four months for the fusion to heal. The time frame in which you can return to work depends on your recovery. Each patient has a unique set of work related issues which will need to be discussed with the doctor.
The first office visit should be scheduled two weeks after you are discharged. The purpose of this visit is to check your incision and make sure you are progressing as planned. The second visit is typically scheduled two to four months after surgery. During this visit the status of your fusion is assessed. Each physician has his own approach to rehabilitation, some more vigorous than others. Your physician will prescribe a rehabilitation program based on your specific needs.

11. DO I NEED A BLOOD TRANSFUSION?

A spinal fusion is a major surgery, which may require a blood transfusion. If you have had prior spine surgery you will most likely need a transfusion. You can donate the blood yourself or you can use the blood bank. The blood bank is very safe; the risk of contracting AIDS is less than one in 300,000. The risk of contracting Hepatitis is one in 10,000. Most of the time pre-donating your own blood can eliminate the need for a blood bank. If you choose to donate your own blood, you can donate from one to three units at one-week intervals. Prior to surgery, our office will arrange the donations through the local blood bank.