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Surgical Treatment Options for Symptomatic Degenerative Disc Disease
The goal of a lumbar fusion is to restore the collapsed disc space to normal, or near normal. Interbody Fusion involves radical removal of the disc(s) between the vertebral body at one or more segments. This is done by inserting blocks of bone (either taken from your hip or obtained from the bone bank), or titanium cages filled with bone, into the space between the vertebrae. The bone grows together with the vertebra and, consequently, stabilizes the area. As a result, one of the initial causes of back and leg pain is eliminated.
The spine can be fused from the front (anterior approach), from the back (posterior approach), or from a combined anterior and posterior approach. In addition, it is common to use additional instrumentation consisting of screw and rods to internally stabilize the motion segment while the fusion becomes solid.
Approximately twelve years ago, research efforts developed an intradiscal prosthesis that restores and maintains the lumbar disc height as the fusion takes place. The intradiscal prosthesis utilizes two small threaded metal cylinders, or cages, to restore the original height of the collapsed disc space. It also opens the intervertebral foramen (the small bony opening where the nerve passes once it leaves the spinal sac), relieves excessive pressure on the facet joints, and decompresses the nerve roots (see diagram). We began using cages in our practice in January of 1997. Our clinical outcome studies, based on over 180 surgical cases, have shown significant reductions in pain and increases in activity levels compared to other spinal instrumentation procedures.
The anterior approach is performed from the front on the lumbar spine with the incision on the lower abdomen. The abdominal contents and major blood vessels are carefully moved aside to expose the vertebra. A separate surgical team, whose specialty is general or vascular surgery, performs the exposure. Once the vertebra is exposed, the neurosurgeon removes the diseased disc. The disc height is then restored using special instruments called spacers. “Threads” are then cut into the vertebrae with a bone tap. The cage is then “screwed” into the threaded space. The cage is packed with bone, which will grow through the holes in the cage and into the vertebral body. Two cages are used at each disc space in most cases. You can reasonably expect these bones to fuse into a solid mass in approximately four to six months.
There are specific advantages/indications for the anterior approach that include the following:
- Patients who have a history of previous spine surgery from the back usually develop scar tissue, making re-operation difficult or sometimes impossible. The anterior approach can safely be performed on these patients as the scar tissue is not encountered
- Once the vertebrae are exposed, the diseased disc is encountered immediately without having to remove the lamina, or bone, as in the posterior approach. Also, the spinal sac and nerve roots are not encountered or manipulated. This eliminates post operative epidural scar tissue formation, which can significantly compress and pinch the spinal sac or nerve roots over time.
- The overall surgical time is decreased with the anterior approach compared to the posterior approach.
- An evaluation is done prior to surgery by the general surgeon performing the anterior exposure.
In some cases, a second stage posterior approach is necessary to provide further stabilization of the fused area. It can be compared to the use of a “C” clamp in a wood shop that holds two pieces of wood together while the wood cement hardens. Stage II is usually performed 3-4 weeks later, and involves an incision made from the back. Bone screws and a spinal plate or rod system affords further stabilization while the fusion solidifies. Normally, it is not necessary to remove the bone (lamina) that covers the spinal sac. However, if scar tissue, bone, or a ruptured disc is pinching a nerve root, nerve root decompression can also be done.
The posterior approach is performed with the incision made from the back. The bone covering the spinal sac, called lamina is removed. Nerve root decompression is achieved by removing some, or all of the bone and soft tissue that covers the top of your spinal sac and the nerve roots. This allows the spinal sac to be retracted, and the disc is then removed. The disc height is then restored using special instruments called spacers. “Threads” are then cut into the vertebra, using a bone tap. The cage is then “screwed” into the threaded space. The cage is packed with bone, which will grow through the holes in the cage and into the vertebral body. Two cages are used at each disc space in most cases. In order to assure that the spinal fusion and nerve root decompression will give you lasting relief from back and leg pain, spine screws with plates or rods are used to complete the operation. Without instrumentation, there is nothing to keep your spine from moving while the fusion occurs.
There are specific advantages/indications for the posterior approach that include the following:
- There is no need for two separate surgeries. The cages are inserted to open the disc space posteriorly. The screws and rod/plate system is then used to immobilize the motion segment while the fusion occurs. If there is a curvature of the spine, or if a spondylolisthesis is present, these are corrected as well.
- If other conditions are present, such as spinal stenosis or a ruptured disc, these are corrected during the posterior approach.
- The anterior approach cannot be performed if you have a history of calcification of the abdominal aorta, which is the main artery that supplies the lower abdomen and legs. This artery lies over the vertebra, and is moved over by the surgical team doing the anterior exposure. If the artery is calcified, it cannot be moved.
- A history of multiple abdominal surgeries may make the anterior approach impossible because of scar tissue.
Risks and Complications of Spinal Fusion
Any surgery, no matter how minor or major, carries with it an element of risk. The following list of complications is included for you to discuss with your surgeon, so you will be able to make the best decision. If you have and concerns, we encourage you to speak frankly with your doctor before agreeing to surgery. Sharing your concerns and resolving reasonable doubts will contribute to your peace of mind and ultimately help you choose the best course of action. Complications in general include, but are not limited to:
- Infection
- Bleeding
- Thrombophlebitis, or blood clots in the legs
- Pulmonary embolism, or blood clots in the lung
- Pneumonia
- Anesthetic related problems, including stroke, heart attack, allergic reactions, and death.
Spinal surgery is not without risk. It is normal to have concerns about possible complications. Complications may occur, affecting your outcome. They can vary depending upon the surgical approach used. Specific complications included, but are not limited to:
- Infection involving the bones or spinal sac. This is a rare, but serious complication. To decrease the likelihood of infection, antibiotics are administered as a preventive measure.
In the event that an infection does occur, prompt treatment will resolve the problem quickly and with a minimum of discomfort and risk.
- Paralysis or weakness involving the extremities. During surgery, the pressure on the spinal nerves is removed. These nerves may be injured during the procedure. In our practice, a high-powered surgical microscope is used to minimize injury.
- Bowel obstruction. While this complication is rare, it can occur with anterior approaches to the lumbar spine. This is usually due to manipulation of the intestine during the surgical exposure.
- Retrograde ejaculation or impotence. This rare complication may occur in men undergoing and anterior exposure to the lumbar spine. Retrograde ejaculation causes the semen containing sperm to be ejaculated in a retrograde fashion, thus rendering the male infertile. This may be of consequence in males who desire children. Impotence may occur due to nerve injury during the anterior exposure.
- Blood vessel damage and bleeding. This is a complication of the anterior approach that occurs during surgery. There is a major artery and vein that lie directly over the vertebrae and must be mobilized and moved to gain exposure. If these vessels are punctured or torn, blood loss can be significant.
- Failed fusion or “non-union". This complication occurs when the bone fails to fuse or join. Certain factors increase the incidence of failed fusion. Insulin dependent diabetic patients (type I diabetes) show a 10% decrease in bone mineral content compared to non-diabetics, increasing the risk of non-union. Osteoporosis or “soft bones” may also prevent a solid fusion from occurring.
Smoking has been directly linked to increased incidence of failed fusion following surgery. The rate of “non-union” in smokers after spinal fusion has been reported to be up to 3-4 times higher than in nonsmokers. Failed fusion is more likely to develop in smokers because inadequate oxygenation of blood flow to the bone graft appears to result in formation of fibrous tissue rather than bone.
The use of non-steroidal anti-inflammatories following a fusion has been linked to higher incidences of failed fusion. Part of the normal healing process and fusion formation involves the “inflammation process.” Anti-inflammatories prevent the normal post-operative inflammation that aids in healing. Anti-inflammatories should not be used for approximately 6 months following a bone fusion unless otherwise directed by your physician. These medications include over-the-counter aspirin and ibuprofen products, including Advil, Motrin, and Aspirin.
The percentage rate of post-operative complications is small, and can be related to your overall medical health. You should have a thorough understanding of the risks and benefits of the proposed surgery.
No guarantees – The goal of spinal surgery is to correct the defect and relieve pressure on the spinal nerves, improving or alleviating pain. But it is not a cure-all. You may have immediate and complete pain relief, or you may have pain for some time, or your pain may actually be worse. This depends on how much damage has been done to the nerve prior to surgery. Your age, your general health and the severity of the damage to your spinal nerves will determine your level of healing. On average, you can expect an 85% reduction in symptoms of pain.
The Recovery Process following a spinal fusion usually lasts 4-6 months. The following are specific guidelines for patients of Dr. Robert Ho, M.D. following a spinal fusion with instrumentation:
- Length of hospitilization is, on average, 3-4
days. In general, hospital stays are becoming shorter due to insurance
and cost. Even though you may be experiencing significant post-operative
pain, pain medications prescribed at discharge will help.
- Post-operative pain is well controlled by the
use of a “pain-pump”. When pain is present, you push a button connected
to the pump, which administers a small amount of pain medication
directly into the intravenous line (I.V.). Pain is decreased or
eliminated within several minutes. Oral pain medications may be given in
addition to the pump.
- You normally are up sitting in a chair or
walking short distances the evening of surgery or the following morning.
- You will be fitted with a back brace prior to
surgery. The back brace is to be worn at all times after surgery,
including in the shower and while in bed. The back brace is worn for
approximately 4-6 months following a fusion. Specific directions
regarding the brace will be sent to your home prior to surgery
- Following discharge home, you will be contacted
by a Home Care nurse. They will make 3-4 home visits to assess healing,
remove the skin staples, and give instructions regarding activity and
brace care. These nurses have received inservice instructions from our
staff, and are skilled and knowlegable regarding the surgery and post op
protocols.
- You should continue to gradually increase your
activity. Walking within and outside the home is encouraged. Try to walk
on a flat, hard surface, such as cement rather than grass.
- Do not sit longer than 30 minutes for the first
several weeks. If you are uncomfortable, take a walk or lie down.
Sitting puts more pressure on you spine than lying or standing/walking.
Recliner chairs are acceptable as long as they support your entire
spine.
- Avoid lifting, bending or strenuous activity.
Do not lift objects greater than 5 pounds. Avoid lifting above waist
level and reaching above your head for any length of time. Maintain a
straight spine. Never bend from your waist. Use your thighs to pick up
something on the floor.
- Rest at frequent intervals. Fatigue contributes
to spasms of the back muscles.
- You are not allowed to drive. At your first
office visit, discuss driving with your doctor. The back brace may
impair your ability to work the gas and break pedals. If you still
require pain medications, you should not operate a vehicle or machinery.
- Limit your time in the car as a passenger to
necessary travel only, such as traveling to the doctor’s office for your
follow-up appointment. After 4 weeks, you can increase time as a
passenger per comfort. Use common sense.
- Climbing stairs at home is permitted. However,
try to limit the number of times you climb the stairs to two times a day
initially. As you are feeling better, you may slowly increase as
necessary. Use a handrail if available. Take your time going up and down
stairs. Make sure to place your entire foot on each step carefully.
- Sexual activity may resume after 4-6 weeks depending on level of pain. Again, common sense is important. If certain activities increase pain levels, refrain from those activities.
Care of Your Incision
For more information or to view the cervical brace, click on the following web site address: http://www.nsg-online.com/Braces/braces.asp
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