Sacroiliac Tests: Interpretation (Explanation of Tests)

The sacroiliac joint can be responsible for lumbar or type pain. sciatica when it is dysfunctional. On the other hand, it is sometimes difficult to identify with precision an attack of this region. To do this, health professionals use in particular clinical sacroiliac tests for diagnostic purposes.

 

This article explains in detail the different sacroiliac tests used in the clinic, and how to interpret them to clarify the diagnosis. Alternatives will also be presented to better guide the management of the patient suffering from pain in this region.

Anatomical reminder

 

Before discussing the clinical tests for the diagnosis of sacroiliac joint involvement, it is worth briefly discussing the anatomy of this joint.

 

The sacroiliac joint connects the bones of the pelvis (called the iliac) to the sacrum, a triangular bone located below the vertebrae lumbar. The main function of the sacroiliac joints is to absorb shocks, and to increase the stability of the trunk.

 

 

It is believed that the sacroiliac joint is responsible for 15 to 30% cases of low back pain. Among the main causes of sacroiliac pain are trauma, anatomical deformities (such as scoliosis or a difference in the length of the lower limbs), inflammatory pathologies, infection, etc.

 

The diagnosis of sacroiliac involvement is not always easy to establish. Besides themedical imaging, a clinical examination integrating several specific tests can highlight a dysfunction of this joint.

 

 

Sacroiliac Test Cluster

 

As sacroiliac involvement can mimic pain in the back, buttocks, or lower extremity, the ability to accurately differentiate involvement of this joint from other causes is important. This will make it possible in particular to eliminate another condition that can reproduce similar symptoms, such as:

 

• herniated disc
• disc protrusion
• inflammatory low back pain
• myofascial syndrome
• degenerative disc disease
• sciatica
• gluteus medius tendonitis
• piriformis syndrome
• narrow lumbar canal
• spondylolisthesis
• Maigne syndrome
• fibromyalgia
• etc.

 

Un sacroiliac test cluster is a group of clinical tests developed to guide the diagnosis of sacroiliac disease to aid in clinical decision making. Essentially, the more positive tests that are identified, the greater the likelihood of sacroiliac involvement.

 

It should be noted that for a test to be considered positive, it must reproduce the patient's characteristic pain (the one he complains about on a daily basis) in the sacroiliac joint. Commonly used tests are:

 

Sacroiliac distraction test

 

• The patient lies on his back with a pillow under his knees. The patient is sometimes asked to place their hands on the lower back in order to maintain the lumbar spine in a lordotic position.
• The examiner places his hands in front of the iliac crests, more specifically on the anterior-posterior iliac spines. The evaluator's arms are crossed, and his elbows are kept extended.
• A slow and gradual downward distraction force is applied (sacroiliac joint distraction force) while leaning toward the patient.

 

 

Sacroiliac compression test

 

• The patient is placed in a lateral decubitus position (on the side) facing the examiner. The symptomatic side is positioned up, and a pillow is placed between the knees as needed.
• The examiner applies progressive downward pressure by pushing on the ilium, more specifically between the iliac crest and the greater trochanter (force of compression of the sacroiliac joint).

 

 

Thigh Thrust Test

 

• The patient lies supine (on the back) with the hip on the affected side flexed 90 degrees. The knees are completely bent.
• The examiner stands on the affected side. He stabilizes the pelvis of the pelvis at the level of the antero-superior iliac spines (ASIS) with his hand.
• The examiner then exerts a progressive pressure in the axis of the femur with his hand and the weight of his body, so as to create an antero-posterior shearing force of the sacral iliac.

 

Gaenslen's test

 

• The patient lies supine (on his back), with the leg on the affected side sticking out of bed so that it hangs down.
• The patient places the unaffected leg in full hip flexion keeping the knee flexed. This creates posterior rotation of the ilium.
• The examiner helps stabilize the leg and pushes the unaffected leg downward. This creates a twisting force at the sacroiliac.

 

 

Faber test

 

• The patient is placed in the supine position (on the back). The assessed leg is placed in position so as to form a 4 (more specifically, the hip is positioned in flexion, abduction and external rotation). The outer side of the assessed ankle should rest on the opposite thigh after positioning the leg for the Faber test.
• While stabilizing the opposite side of the pelvis (at the level of the antero-superior iliac spine), the evaluator exerts a force aimed at pushing the knee of the affected leg towards the table. This is equivalent to a combined movement of flexion, abduction and external rotation.

 

 

Other

 

There are other lesser-known tests that help clarify sacroiliac involvement. Some studies include them in their diagnostic cluster. These include the following tests, among others:

 

• flamingo test
• Posteroanterior sacroiliac shear
• Gillet's test
• “Sacral Thrust0” test
• Palpation of the sacroiliac
• etc.

 

Note: To know the metrological qualities of the previous tests (inter-evaluator reliability, kappa score, LR+, LR-, etc.), see the following article.

 

Essentially, scientific research findings show that when three or more of these pain provocation tests are positive, there is a high likelihood that sacroiliac dysfunction is present.

 

 

Diagnostic Tool of Choice: Sacroiliac Infiltration

 

In addition to clinical sacroiliac pain provocation tests, other methods can be used to clarify the diagnosis.

 

Indeed, if the doctor believes that the symptoms come from a dysfunction of the sacroiliac joint, your doctor may offer you a sacroiliac infiltration for diagnostic purposes. This essentially consists of inject a local anesthetic and/or an anti-inflammatory agent in the sacroiliac joint.

 

 

Specifically, he will inject a local numbing agent (such as lidocaine or bupivicaine) into the sacroiliac joint to determine if you experience temporary relief. This infiltration is generally done under fluoroscopy, that is to say guided by a medical imaging.

 

After the diagnostic infiltration, the doctor could re-test the movements that were previously painful (such as the clinical tests mentioned above). If you feel less pain in general, we can conclude that the sacroiliac joint was inflamed (and the cause of your pain!).

 

We will then concentrate the treatment around the sacroiliac, for example with subsequent infiltrations. Most often, anti-inflammatory agents (such as cortisone) will be used considering their prolonged effectiveness. These infiltrations will then be therapeutic, not diagnostic.

 

If, on the contrary, there is no therapeutic effect, this would mean that your symptoms come from another structure, or from another cause.

 

To know everything about sacroiliac infiltration (procedure, risks, effectiveness, etc.), see the following article.

 

 

Conclusion

 

To identify damage to the sacroiliac joint, healthcare professionals use several diagnostic tools. Among the most popular are medical imaging, infiltration under fluoroscopy, or clinical pain provocation tests.

 

The clinical tests are easy to carry out and make it possible to direct the management according to the patient's response. It should be noted that there is no single test that makes it possible to conclude beyond any doubt that sacroiliac dysfunction is present. Rather, it is a combination of positive tests that points to a condition in that joint.

 

 

Resources

Video on sacroiliac pain:

 

 

References

 

• https://si-bone.com/providers/resources/diagnostic/provocative-tests
• https://www.webmd.com/back-pain/si-joint-dysfunction-diagnosis