With any surgery, there is the risk of complications. When surgery is done near the spine and spinal cord these complications can be very serious-if they occur. The chance that any of these complications will occur during your surgery or during your recovery is usually very small. You should discuss these complications with your doctor before surgery if you have any questions that are not answered here. This is not intended to be a complete list of the possible complications, but these are the most common.
Implant & Fusion Complications
Most spinal operations require general anesthesia. A very small number of patients may have problems from it. These problems can arise from reactions to the drugs used, other medical conditions you may have, or problems with the anesthesia. Anesthesia affects how the lungs work and can pose problems with lung infections. Nausea and vomiting can occur and are usually treated with medications. The tube inserted into your throat may cause soreness after surgery. In rare cases the tube can harm the vocal cords. Be sure to talk to your doctor and anesthesiologist about possible complications.
Surgery on the spine involves the risk of unexpected bleeding. Spine surgeries performed through the abdominal cavity require the surgeon to move the abdominal aorta and large vessels going to the legs out of the way. Doctors take extra care while performing surgery to avoid harming nearby blood vessels.
Deep venous thrombosis (DVT) (or thrombophlebitis) is the medical name to describe blood clots formed in the veins of the legs. This is a common problem following many types of surgical procedures. These blood clots form in the large veins of the calf. They may continue to grow and extend up into the veins of the thigh, and in some cases into the veins of the pelvis.
It is true that some people develop DVT even though they have not undergone any recent surgery. But the risk is much higher following surgery-especially surgery involving the pelvis or the lower extremities. There are logical reasons why the risk is increased. The body is trying to stop bleeding associated with surgery, so the body's clotting mechanism becomes very active during this period. Also injury to blood vessels around the surgical site from normal tugging and pulling during surgery can set off the clotting process. Blood that does not move well sits in the veins and becomes stagnant. If it sits too long in one spot it may begin to clot.
The prevention of DVT is a serious matter. Blood clots that fill the deep veins of the legs stop the normal flow of venous blood from the legs back to the heart. This causes swelling and pain in the affected leg. If the blood clot inside the vein does not dissolve, the swelling may become chronic and can cause permanent discomfort. While the discomfort is unpleasant, the blot clot actually poses much more serious danger. If a portion of the forming blood clot breaks free inside the veins of the leg, it may travel through the veins to the lung. There it can lodge itself in the tiny vessels of the lung, cutting off the blood supply to the blocked portion of the lung. This blocked portion cannot survive and may collapse. This is called a pulmonary embolism. If a pulmonary embolism is large enough, and the portion of the lung that collapses is large enough, it can cause death.
Reducing the risk of developing DVT is a high priority following any type of surgery. Preventative measures fall into two categories, mechanical involves getting the blood moving better, and medical involves using drugs to slow the clotting process.
Blood that is moving is less likely to clot. Getting you moving so that your blood is circulating is perhaps the most effective treatment against developing DVT. Once you begin walking, your leg muscles will contract and keep the blood in the veins of the legs moving. But you can still do things while you are in bed to increase the circulation of blood from the legs back to the heart. Simply pumping your feet up and down (like pushing on the gas pedal) contracts the muscles of the calf, squeezes the veins in the calf, and pushes the blood back to the heart. You should do these exercises as often as you can.
Pulsatile stockings are very effective. They are special stockings that wrap around each calf and thigh. A pump inflates them every few minutes, squeezing the veins in the legs and pushing blood back to the heart. Support hose, sometimes called TED hose, are still commonly used following surgery. The hose work by squeezing the veins of the leg shut. This reduces the amount of stagnant blood that is pooling in the veins of the leg and lowers the risk of blood clotting.
Medications that slow down the body's clotting mechanism can reduce the risk of DVT. They are widely used following surgery of the hip and knee. Aspirin can be used in very low risk situations. Heparin shots may be given twice a day in moderately risky situations. When there is a high risk for developing DVT, several potent drugs are available that can slow the clotting mechanism very effectively. Heparin can be given by intravenous injection, a new drug called Lovenox can be given in shots administered twice a day, and Coumadin can be given by mouth. Coumadin is the drug of choice when the clotting mechanism must be slowed for more than a few days because it can be taken orally.
In most cases of spinal surgery, both mechanical and medical measures are used simultaneously. It has become normal practice to use pulsatile stockings and place patients on some type of medication to slow the blood clotting mechanism. You are encouraged to get out of bed as soon as possible and begin exercises immediately after surgery.
A watertight sac of tissue (dura mater) covers the spinal cord and the spinal nerves. A tear in this covering can occur during surgery. It is not uncommon to have a dural tear during any type of spine surgery. If noticed during the surgery, the tear is simply repaired and usually heals uneventfully. If it is not recognized, the tear may not heal and may continue to leak spinal fluid, which can cause problems later. The leaking spinal fluid may cause a spinal headache. It can also increase the risk of infection of the spinal fluid (spinal meningitis). If the dural leak does not seal itself off fairly quickly on its own, a second operation may be necessary to repair the tear in the dura.
It is important that your lungs are working at their best following surgery to ensure that you get plenty of oxygen to the tissues of the body that are trying to heal. Lungs that are not exercised properly after surgery can lead to poor blood oxygen levels and can even develop pneumonia.
There are several reasons why your lungs may not work normally after surgery. If you were put to sleep with a general anesthetic, the medications used may temporarily cause the lungs to not function as well as normal. This is one reason that a spinal type anesthetic is recommended whenever possible. Lying in bed prevents completely normal function of the lungs, and the medications you take for pain may cause you to not breathe as deeply as you normally would.
After surgery you will need to do several things to keep your lungs working at their best. Your nurse will encourage you to take frequent deep breaths and cough often. Getting out of bed, even upright in a chair, allows the lungs to work much better. You will be allowed to get up and into a chair as soon as possible. Respiratory therapists have tools to help maintain optimal lung function. The incentive spirometer is a small device that measures how hard you are breathing and gives you a tool to help improve your deep breathing. If you have any other lung disease, such as asthma, the respiratory therapist may also use medications that are given through breathing treatments to help open the air pockets in the lungs.
There is a risk of infection any time surgery is performed. Surgeons take every precaution to prevent infections. You will probably be given antibiotics right before surgery-especially if bone graft, metal screws, or plates will be used. Infections occur in less than 1% of spinal surgeries.
An infection can be in the skin incision only, or it can spread deeper to involve the areas around the spinal cord and the vertebrae. A wound infection that involves only the skin incision is considered superficial. It is less serious and easier to treat than a deeper infection. A superficial wound infection can usually be treated with antibiotics, and perhaps removing the skin stitches. The deeper wound infections can be very serious and will probably require additional operations to drain the infection. In the worst cases, any bone graft, metal screws, or plates that were used may need to be removed. Contact your doctor immediately if you suspect that you have an infection. Some indications of infection include
- surgical wound that is red, hot, swollen and does not heal
- clear liquid or yellow pus oozing from the wound
- wound drainage that smells bad
- increasing pain
- fever and shaking chills
Some spinal operations are simply unsuccessful. One of the most common complications of spinal surgery is that it does not get rid of all of your pain. Some pain after surgery is expected. If you experience chronic pain well after the operation, you should let your doctor know.
In some cases the procedure may actually increase your pain. Be aware of this risk before surgery and discuss it at length with your surgeon. He or she will be able to give you some idea of your chances of not getting the relief that you expect.
Any time surgery is done on the spine, there is some risk of injuring the spinal cord, which can lead to nerve damage. The nerves in each area of the spinal cord connect to specific parts of your body. This is why damage to the spinal cord can cause paralysis in certain areas and not others; it depends on which spinal nerves are affected.
Spinal Cord Injury
Operations on the spine have some risk of injuring the spinal cord or spinal nerves. This can occur from instruments used during surgery, from swelling, or from scar formation after surgery. Damage to the spinal cord can cause paralysis in certain areas and not others. Injured nerves can cause pain, numbness, or weakness in the area supplied by the nerve.
The spinal cord and spinal nerves carry the nerve signals that allow the rest of your body to function and to feel sensation. Damage to the spinal cord and the nerves around the spinal cord can cause many problems. If a nerve is damaged that connects to the pelvic region, it may cause sexual dysfunction.
Delayed Union or Nonunion
A certain number of fusions simply do not heal as planned. This type of problem case is called a "nonunion". A nonunion may require a second operation to try to get the bones to heal. Some fusions will take longer than expected to heal. This type of problem case is called a "delayed union".
Metal screws, plates, and rods are used in many different types of spinal operations as part of the procedure to hold the vertebrae in alignment while the surgery heals. These metal devices are called "hardware". Once the bone heals, the hardware is usually not doing much of anything. Sometimes the hardware can either break or move from the correct position before the surgery is completely healed. This is called a hardware fracture. If this occurs it may require a second operation to either remove or replace the hardware.
Implant migration is a term used to describe an intervertebral fusion cage that has moved out of place. When this happens, it usually occurs soon after surgery, before the healing process has progressed to the point where the cage is firmly attached by scar tissue or bone growth. If the cage moves too far, it may not be doing its job of stabilizing the two vertebrae. If it moves in a direction towards the spine or large vessels, it may damage those structures. A problem with implant migration may require a second operation to replace the cage that has moved. Your doctor will check the status of the hardware with X-rays taken during your follow-up office visits.
The term "pseud" means false and "arthrosis" refers to joint. The term "pseudarthrosis" then means false joint. A surgeon uses this term to describe either a fractured bone that has not healed or an attempted fusion that has not been successful. A pseudarthrosis usually means that there is motion between the two bones that should be healed (or fused together).
There is usually continued pain when the vertebrae involved in a surgical fusion do not heal. The pain may increase over time. The spinal motion can also stress the metal hardware used to hold the fusion-possibly causing them to break. You may need additional surgery for a pseudarthrosis. Your surgeon might want to add more bone graft, replace the metal hardware, or add an electrical stimulator to try to get the fusion to heal.
The spine behaves like a chain of repeating segments. When the entire spine is healthy, each segment works together to share the load throughout the spinal column. Each segment works with its neighboring segment to share the stresses imposed by movements and forces. When one or two segments are not working properly, the neighboring segments have to take on more of the load. It is the segment closest to the non-working segment that gets most of the extra stress. This means that if one or more levels are fused anywhere in the spine, the spinal segment next to where the surgery was performed begins to take on more stress. Over time this can lead to increased wear and tear to this segment, eventually causing pain from the damaged segment. This is called a transitional syndrome because it occurs where the transition from a normal area of the spine to the abnormal area that has been fused.