Sacroiliac (SI) Joint FAQ

  1. What are some causes for pain in the lower back, buttocks or pelvic region?
  2. Where is my sacroiliac joint?
  3. How does my sacroiliac joint work?
  4. Why does the sacroiliac joint start having problems?
  5. How does the sacroiliac joint cause pain?
  6. How common are sacroiliac joint problems?
  7. How does sacroiliac joint pain manifest?
  8. Who is at risk for sacroiliac joint problems?
  9. How would I know that my sacroiliac joint may not be functioning properly?
  10. Will my doctor check for sacroiliac joint problems?
  11. What should I tell my doctor about my back or buttock pain?
  12. How would my doctor determine whether I have sacroiliac joint dysfunction?
  13. How easy is it to diagnose sacroiliac joint dysfunction?
  14. What are some options for treatment of sacroiliac joint dysfunction?
  15. How well does sacroiliac joint fusion work?

1. What are some causes for pain in the lower back, buttocks or pelvic region?

Low back pain is a common symptom that affects many people during their lifetime. For some, low back pain can be an acute, short-term problem. Others experience chronic, long-term symptoms. There are many structures in the lower back and pelvic area that can cause pain. Most commonly, people think of a slipped disc as a cause of low back pain. The word sciatica may be used when describing low back pain. Occasionally, hip problems can be confused with low back conditions.

In fact, there are many causes of back pain, including arthritis of the back, osteoporosis, and a poorly aligned spine. The sacroiliac joint can be a significant contributor to pain in the lower back, pelvic region, buttocks, or legs.

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2. Where is my sacroiliac joint?

The sacroiliac joint is located in the pelvis, linking the iliac bone (pelvis) to the sacrum (lowest part of the spine above the tailbone).

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3. How does my sacroiliac joint work?

The function of the sacroiliac joint is to transfer weight and forces due to movement from your upper body through the pelvis to your legs and vice versa. Your pelvis acts as a central base through which large forces are transferred and dissipated. The primary role of the sacroiliac joint is to provide stability for the pelvis.

The normal sacroiliac joint also has limited motion that allows it to dissipate and transfer significant stresses. The amount of motion is small, and is quite difficult to assess in a physical examination.

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4. Why does the sacroiliac joint start having problems?

If the motion in your pelvis is asymmetric, then dysfunction can occur in your sacroiliac joint. You could have asymmetric motion if your legs are significantly different in length. This can be congenital or caused due to an injury or illness such as polio or scoliosis. Other conditions that can predispose you to sacroiliac joint dysfunction include having one leg that is weaker, such as seen with hip osteoarthritis. These biomechanical conditions, or even wearing inappropriate footwear, can alter your gait and cause repetitive stress to your sacroiliac joint and related structures. Other potential causes of Sacroiliac (SI) Joint problems include degenerative disease, history of trauma, pregnancy/childbirth, and other unknown reasons.

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5. How does the sacroiliac joint cause pain?

The sacroiliac joint is a type of joint known as a synovial joint. This type of joint has free nerve endings that can cause chronic pain if the joint degenerates or does not move properly.

The sacroiliac joint has been long known to cause pain in the lower back and buttocks. Like any other joint in the body, the sacroiliac joint can become arthritic or its support ligaments can become loose or injured. When this happens, people can feel pain in their back, especially with lifting, running or even walking. In these cases, the pain is felt in the back, sometimes similar to the pain caused by a “disc” or spinal arthritis.

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6. How common are sacroiliac joint problems?

It is commonly reported in clinical literature that up to 33% of all low back pain is caused by the Sacroiliac (SI) Joint. Many risk factors are associated with lower back pain, and many are directly associated with lumbar disc injury. These may include, smoking, poor physical condition, positive family history, and occupational lifting.

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7. How does sacroiliac joint pain manifest?

Many people have sacroiliac pain that begins spontaneously. However, over half the time Sacroiliac (SI) Joint pathology can be related to a specific event, often an injury. It is difficult to directly relate any specific functioning difficulty (including walking, sitting, standing, sleeping on the affected side, job activity, bowel movements, cough, sneeze, etc.) to the sacroiliac joint as a source of pain. The most significant indication is the specific location of the pain below the L5 joint.

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8. Who is at risk for sacroiliac joint problems?

Women may be at increased risk for sacroiliac joint problems because of their broader pelvises, the greater curve of their necks, and shorter limb lengths. In addition, pregnancy often leads to stretching of the pelvis, specifically in the sacroiliac ligaments. Injury from accidents is another predisposing factor for sacroiliac joint pain.

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9. How would I know that my sacroiliac joint may not be functioning properly?

If you have trouble sleeping comfortably, or frequently experience your knee giving way, pain in certain lying or bending positions, or tenderness in your buttocks, you may have sacroiliac joint dysfunction.

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10. Will my doctor check for sacroiliac joint problems?

Doctors do not always look for the sacroiliac joint as a source of lower back pain, although many articles have been written about it. Sometimes your back pain may have been previously diagnosed as lumbar spinal pain. However, if your symptoms don't fit what the doctor can see on an MRI, this may indicate that your pain is coming from a place other than the lumbar spinal region.

Your doctor may determine if your sacroiliac joint is the source of your pain by ruling out other sources of pain as well as running specific tests.

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11. What should I tell my doctor about my back or buttock pain?

The most important information you can give your doctor is the exact location of your pain. Try to notice when the pain occurs and how intensely you feel it in various locations, including your low back, buttocks, and legs.

Also, be sure to tell your doctor about any previous injury that may have either directly affected your pelvis, or caused you to walk asymmetrically.

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12. How would my doctor determine whether I have sacroiliac joint dysfunction?

Your doctor would consider all the information you provide, including any history of injury, location of your pain, and problems standing or sleeping.

Your doctor will also give you a physical examination. You may be asked to stand or move in different positions and point to where you feel pain. Your doctor may manipulate your joints or feel for tenderness over your sacroiliac joint. All of these can help establish a diagnosis of sacroiliac joint dysfunction.

In addition, X-rays, a CT scan, or MRI may be helpful in diagnosis of Sacroiliac (SI) Joint dysfunction. It is also important to remember that more than one condition (like a disc or hip problem) can co-exist with Sacroiliac (SI) Joint dysfunction and your doctor will need to check for other factors that may be causing your pain.

The most reliable method to accurately determine the cause of sacroiliac joint pain is to inject the Sacroiliac (SI) Joint with painkillers. Your doctor will deliver the injection with either fluoroscopic guidance or CT guidance to ensure that the needle is accurately placed in the sacroiliac joint. If, following the injection, your pain is decreased by more than 75%, then it can be concluded that the Sacroiliac (SI) Joint is either the source, or a major contributor, to your low back pain. If the level of pain does not change after the injection, it is less likely that the sacroiliac joint is the cause of your low back pain.

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13. How easy is it to diagnose sacroiliac joint dysfunction?

It is not always easy to diagnose sacroiliac joint dysfunction. Sometimes your physical findings may indicate a sacroiliac joint dysfunction, but chronic changes may also be seen in your lumbar spine. Your doctor may discuss the difficulty of making a correct diagnosis in the presence of multiple abnormalities. To confirm the sacroiliac joint as the source of low back pain, injections are invaluable. Provocation tests are helpful for localizing the pain source.

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14. What are some options for treatment of sacroiliac joint dysfunction?

There are several options for treating sacroiliac joint dysfunction. Some people respond to physical therapy, chiropractic manipulations, and exercises. Others require more interventional treatments including various oral medications, therapeutic injections, or radiofrequency treatments. Usually pain improvement using these therapies is temporary and treatments may need to be performed repeatedly to treat recurrent pain.

Long-term pain relief can be accomplished through a surgical procedure known as sacroiliac joint arthrodesis or Sacroiliac (SI) Joint fusion. This procedure reduces pain by stabilizing and fixing the joint and eliminating the joint motion.

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15. How well does sacroiliac joint fusion work?

Sacroiliac joint fusion has been shown in clinical publications to resolve back pain with a high degree of reliability. By fusing the sacroiliac joint, the joint may be fixed to its intended position and weight-bearing function.

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An Advanced Approach to Surgical Management of SI Joint Dysfunction
Up to 25% of all low back pain is SI Joint in origin – but the diagnosis of SI Joint disease is frequently overlooked. (Cohen, et al.)
It is common to link low back pain with protruding disc even when neurological signs are absent. (Weksler, et al.)
It is common for pain from SI Joint dysfunction to mimic discogenic or radicular low back pain. (Weksler, et al.)
Many patients go on to receive lumbar fusion instead of SI Joint fusion – so SI Joint disease should be strongly considered in differential diagnosis of low back pain. (Weksler, et al.)
Now there is an approach to surgical management of SI Joint dysfunction that’s easier and less invasive than traditional open surgery.
The iFuse Implant System consists of porous plasma spray coated implants, surgically inserted across the SI Joint to create fixation leading to fusion—from the inside.
The iFuse creates a biomechanically rigorous fixation/fusion system, designed to support reliable fixation/fusion and acute weight bearing capacity.
With the iFuse Implant System, there is no need for BMP in conjunction with autologous bone graft or additional pedicle screws, rods or hollow modular anchorage screws or cannulated compression screws or threaded cages within the joint or fracture fixation screws.
iFuse benefits:
The iFuse Implant System is designed to be the sacroiliac joint fusion/fixation method of choice for spine surgeons.
iFuse is a minimally invasive surgical solution to replace open surgical SI Joint fusion.
With iFuse there's minimal incision size, minimal soft tissue stripping, minimal tendon irritation and reduced risk of infection.
iFuse is a simplified minimally invasive surgical procedure.
Just drill, broach, insert Implants and close.
iFuse has a simple technique which reduces OR time to less than 1 hour.
iFuse has 3X shear and 7X bending strength compared with screws.
iFuse has improved patient perception of stability post-implant.
The incidence of SI joint degeneration in patients was 75% at 5 years post-fusion, which was significantly higher than in the non-fusion group, 38.2%. (Ha, et al.)
Among patients with one-segment fusion, 91% developed SI joint degeneration. (Ha, et al.)
Regardless of whether the fusion includes the sacrum, the SI joint is influenced by increased mechanical stress arising from lumbar/lumbosacral fusion. (Ha, et al.)
Posterolateral lumbar/lumbosacral fusion can be a cause of SIJ degeneration. (Ha, et al.)