Introduction
In the first part of the 20th century, sacroiliac joint (SI joint) syndrome was the most common diagnosis for low back pain, or lumbago.
Before 1932, SI joint syndrome was a particularly popular diagnosis. It was actually called the "Era of SI Joint" because so many physicians felt that the SI joint was the cause of most back problems. Any pain in the low back, buttock or adjacent leg was usually referred to as SI joint syndrome.
In 1932, the discovery of the herniated (or ruptured) disc led many physicians to assume that most pain in the back was the result of this new problem. Thus was born the "Dynasty of the Disc", and the SI joint was somewhat forgotten.
In the late 1980s, many physicians "rediscovered" the SI joint as a possible source of back pain. Yet, even today SI joint pain is often overlooked as a cause of low back pain. Many physicians have not been trained to consider it when diagnosing back pain and many are still reluctant to believe a joint that has so little movement can cause back pain. The symptoms of back pain from problems in the SI joint are difficult to distinguish from other types of low back pain.
This document will offer you valuable information about the following:
Anatomy
The sacroiliac joint (SI joint) is one of two joints in your pelvis that connect the tailbone (the sacrum) and the large pelvic bone (the ilium). The SI joints connect your spine to the pelvis, and thus, the entire lower half of the skeleton. Like all true joints, there is articular cartilage on both sides of the SI joint surfaces.
However, the SI joint is unlike any other joint in the body, because it is covered by two different kinds of cartilage. The articular surfaces have both hyaline (glassy, slick) and fibrocartilage (spongy) surfaces that rub against each other. No other joints have this feature! The joint also has many large ridges and depressions (ridges are bumps and depressions are dips in the surface) that fit together like pieces in a puzzle.
(Unlike most other joints, the SI joint is not designed for much motion. In fact, it is common for the SI joint to become stiff and actually "lock" as we age. This might explain why manipulation and mobilization techniques have proven to be useful in physical therapy for SI joint syndrome. Mobilization is a technique where a joint is mobilized or loosened by certain exercises and stretches that the therapist can perform or teach you to perform.
The SI joint usually only moves about two to four millimeters during weight bearing and forward flexion. This small amount of motion occurring in the joint is described as a "gliding" type of motion. The motion is quite different than the hinge motion of the knee or the ball and socket motion of the hip. The SI joint is a "viscoelastic joint", meaning that its major movement comes from giving or stretching. The SI joint's main function appears to be providing shock absorption for the spine through stretching in various directions. The SI joint may also provide a "self-locking" mechanism that helps you to walk. The joint locks on one side as weight is transferred from one leg to the other.
Due to its small amount of movement and its complexity, finding out about the SI joint's motion is very difficult during a physical examination. This is one of the big problems in diagnosing SI joint problems.
Causes
One of the most common causes of problems at the SI joint is an injury. The injury can come from a direct fall on the buttocks, a motor vehicle accident, or even a blow to the side of your pelvis. The force from these injuries can strain the ligaments around the joint. Ligaments are the tough bands of connective tissue that hold joints together. Tearing of these ligaments can lead to too much motion in the joint. The excessive motion can eventually lead to wear and tear of the joint and pain from degenerative arthritis. Injuries can also cause direct injury of the articular cartilage lining the joint. This too, over time will lead to degenerative arthritis in the joint.
In some patients, pain occurs because of an abnormality of the sacrum bone itself. The sacrum bone is actually a very specialized set of vertebrae (the bones that make up the spine). Before birth, when your body is undergoing development in the womb, several vertebra fuse together to form the sacrum. However, in some people, the bones that make up the sacrum never fuse together. In these cases, two or more of the vertebra that should fuse together remain separated. This creates an odd situation where the SI joint is somewhat malformed, and a false joint occurs. This is sometimes called a "transitional syndrome". This problem can be seen on X-rays. People who have this syndrome seem to have more problems with their SI joints, as well as back pain that appears to come from that area.
Women are at risk for developing SI joint problems later in life due to childbirth. During pregnancy, female hormones are released that allow the connective tissues in the body to relax. The relaxation is necessary so that during delivery, the female pelvis can stretch enough to allow birth. This stretching results in changes to the SI joints, making them "hypermobile" - extra or overly mobile. Over a period of years, these changes can eventually lead to wear-and-tear arthritis. As would be expected, the more pregnancies a woman has, the higher her chances of SI joint problems.
During pregnancy, the SI joints can cause discomfort both from the effects of the hormones that loosen the joints, and from the stress of carrying a growing baby in the pelvis.
Many other problems can lead to degenerative arthritis of the SI joints. It is often hard to determine exactly what caused the wear and tear to the joint.
Symptoms
SI joint problems have numerous symptoms. Following are the most common:
In most cases, there is a confusing pattern of back and pelvic pain that mimic each other, making diagnosis of SI joint problems very difficult.
Diagnosis
The diagnosis usually begins with a history of the problem. Your health care provider will want to ask you questions such as:
Following this, your provider will perform a physical examination to try to find the source of your back pain. Many of the tests will be trying to determine whether the problem is coming from the spine or from the SI joint.
Your clinical exam may include the following orthopedic tests used to determine if the SI joint is involved. Pain during these tests is generally an indicator that the SI joint is indeed a problem.
X-rays may also be recommended by your provider to determine if there are abnormalities of the joint that can be seen on X-rays.
A CAT scan can sometimes show more detail about the joint surfaces and the surrounding bone. If the X-rays suggest something may be affecting the SI joint, your provider may recommend a CAT scan to get a better look.
A bone scan can be useful in determining if the joint is inflamed. An inflamed SI joint usually shows up as a hot spot on a bone scan of the pelvis. To learn more about the bone scan and CAT scan and how they are done, refer to the document entitled:
Your provider may also recommend that you undergo a fluoroscopic injection into the joint. During this test, a local anesthetic is injected into the joint. The doctor uses the fluoroscope to make sure the needle is actually in the joint before injecting the medication. The SI joint is located fairly deep in the upper buttock and is covered by thick muscle. It is difficult to put a needle into the joint without some guidance. A fluoroscope is a special TV camera that uses X-rays to allow the doctor to see on the screen the exact placement of the needle, making sure it is positioned accurately. Once the doctor is sure that the needle is in the right place, the anesthetic is injected to numb the joint. If the pain goes away, your provider can be relatively sure that the problem is coming from the SI joint and not somewhere else in the spine. The doctor may also add a dose of cortisone to the injection to help ease your pain. Cortisone is a powerful anti-inflammatory medication that calms the arthritis inside the joint and reduces your pain. The effect is usually temporary, but may last up to several months.
Treatment
If your provider feels that your back pain may be a result of SI joint syndrome, you will likely be presented with two completely different treatment options. These two options for non-surgical treatment may appear to be exact opposites - manipulation or stabilization. Why would the two treatments for one joint be so different? No one really knows what causes the pain from an SI joint that is not suffering from severe degenerative arthritis. In some cases, it appears that the joint is "too stiff" or "locked" and needs to be more mobile to function correctly. In these cases, the pain seems to respond to mobilization of the joint. In other cases, especially when there are definitely arthritis changes noticeable on X-rays, reducing the mobility of the joint may decrease the pain. Treatment is understandably varied and the results of treatment have been difficult to assess because of the complexities of the SI joint. The appropriate approach is still somewhat unclear to many providers.
Both the mobilization approach and the stabilization approach to treatment involve physical therapy. Mobilization of the joint may include exercises and manipulation by the therapist. This type of therapy is directed to loosening up the joint ligaments, allowing the joint to move in a normal fashion. Stabilization of the joint may include muscle strengthening and pelvic stabilization exercises to reduce the movement in a joint that appears to be too loose.
For a complete explanation of the rehabilitation for sacroiliac joint dysfunction you may wish to review the document entitled:
Stabilization can also be accomplished through use of a specific brace called the sacroiliac belt. The belt wraps around the hips to squeeze the SI joints together. This supports and stabilizes the pelvis and SI joints.
For a complete explanation of thebraces used for for sacroiliac joint dysfunction you may wish to review the document entitled:
If all conservative methods of treatment fail, surgery may become an option. Surgery on the SI joint usually consists of a fusion of the joint (also called an "arthrodesis"). Fusing the two sides of a joint together to reduce pain has been used for many years as a treatment for arthritic joints. Today, the fusion of the SI joint is not a common operation, but when necessary can reduce the pain associated with SI joint syndrome. Your surgeon will want to be absolutely sure that the pain you are experiencing is coming from the SI joint before suggesting this operation. You should discuss the procedure with your surgeon and understand what can be expected from the operation.
An SI joint fusion is performed by first, making an incision over the SI joint in the lower back. The joint is opened so the surgeon can see each joint surface. Once the joint surfaces are in clear view, the articular cartilage lining the joint is removed from both surfaces. This leaves a fresh surface of bone instead of the normal cartilage. The bone surfaces are then held together until they actually heal together, or fuse. Without the articular cartilage of the joint, the body treats the two raw bone surfaces just like a fracture and tries to heal them as it normally would any broken bone.
To hold the bones together, the surgeon will usually insert several metal screws across the joint. Bone graft may also be placed around the joint to help the fuse the joint. The bone graft is usually removed from the pelvic bone right beside the SI joint. To learn more about how bone graft is removed from the pelvis and the different types of bone graft, you may wish to refer to the document entitled:
Following surgery, you will probably stay in the hospital for two to four days. Once discharged, you will be given instructions by your surgeon about what to watch for and how much activity you will be allowed in the first few weeks. Your skin incision will generally heal in 10 to 14 days. The fusion of the bones usually takes 12 to 18 weeks to become strong enough to resume your normal activities. Your surgeon will take X-rays several times after the procedure to follow your healing progress and determine when the bones have fused.
Complications
With any surgery, there is a risk of complications. When surgery is done near the spine and spinal cord these complications (if they occur) can be very serious. Complications could involve subsequent pain and impairment and the need for additional surgery. You should discuss the complications associated with surgery with your doctor before surgery. The list of complications provided here is not intended to be a complete list of complications and is not a substitute for discussing the risks of surgery with your doctor. Only your doctor can evaluate your condition and inform you of the risks of any medical treatment he or she may recommend.
Please review the document entitled:
Following is a list of complications possible with SI joint fusion. This is not meant to be a complete list of all the possible complications, but these are the most common:
Bleeding
Most major surgical operations can result in unexpected blood loss. The SI joint fusion is no different. The operation is not performed near any large major vessels so the risk of serious blood loss is quite low.
Nerve Injury
During the operation, the surgeon will be working close to the nerve roots that exit the spine near the SI joint. These nerves may be damaged. In some cases, the injury to the nerves may be temporary and return to normal over time. In other cases, the nerve damage may be permanent. If this occurs, it can result in weakness, numbness, or pain.
Persistent Pain
Some pain after surgery is expected, but if you experience chronic pain well after the operation, you should let your doctor know. Not all operations are successful and some may even make the situation worse. If your pain is coming from an area of the body other than the SI joint, your pain may continue. It is difficult to be absolutely sure before surgery that the operation will cure your pain.
Hardware Breakage
If screws used for fixation of the fusion do not work, hardware removal and reoperation may be required. Your doctor will have to check the status of the hardware with X-rays. The screws may be placed in the wrong position (without the surgeon realizing this at the time of surgery). The screws may also move after surgery and begin to "back out", or they may break. One of the main causes of a screw breaking after surgery is that the fusion has not healed. The screws will not be able to hold indefinitely if the fusion has not become solid. Eventually the screws will break due to the constant motion across the joint. If this occurs, the screw may need to be removed or the fusion may have to be repeated to attempt to get the bones to heal.
Non-union/Delayed union
A certain number of fusions simply do not heal as planned. This type of problem case is called a "non-union". Some will take longer than expected to heal. This type of problem case is called a "delayed union". A non-union may require a second operation to try to get the bones to heal. Most surgeons do not consider an SI joint fusion to be non-union until six to eight months have passed with no evidence of healing.
Infection
With any surgery, there is a small risk of infection. An infection can be superficial or it can be a deep infection. A superficial infection occurs when only the skin incision becomes infected. This type of infection is usually easier to treat and may be cured by using antibiotics for several weeks. The surgeon may also remove the sutures and open the wound slightly to drain the infection. A deep infection is more serious. The infection may spread down into the joint, into the bone, and around the metal screws. A deep infection may require antibiotics and additional operations to drain the infection. An infected incision will usually cause an increase in pain and may ooze a liquid, or pus. You may feel ill and run a temperature. If you feel you may have an infection, contact your doctor immediately so the wound can be treated and medication can be prescribed if necessary.
Copyright © 2003 DePuy Acromed.
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