Cluster of Laslett

Sacroiliac joint pain can be effectively managed when assessed with Cluster of Laslett's tests. Learn the diagnostic and treatment strategies.

By Joshua Napilay on Jun 06, 2024.

Fact Checked by Ericka Pingol.

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What is sacroiliac joint pain?

Sacroiliac (SI) joint pain is discomfort arising from the sacroiliac joints, which connect the base of the spine (sacrum) to the pelvis (iliac bones). Causes of SI joint pain include trauma, arthritis, pregnancy, biomechanical issues, or prolonged sitting/standing. 

The pain often radiates from the lower back or buttocks to the thighs. Patients with a lower back may experience stiffness, difficulty standing or walking, and worsening pain during specific activities like bending, climbing stairs, or transitioning from sitting to standing. Proper diagnosis and targeted treatment can help alleviate discomfort and improve mobility.

How to diagnose sacroiliac joint pain

Diagnosing SI joint pain requires a comprehensive clinical assessment that includes a detailed patient history, physical examination, and provocative tests. 

Patient history and symptoms

Lower back pain is often felt in the buttocks and may extend to the thighs. It may worsen when sitting, climbing stairs, or changing from sitting to standing. It's important to know if there has been any previous injury, pregnancy, or arthritis, as this may help better understand the condition.

Physical examination

When assessing the SI joint area, check for tenderness by gently touching the area. Evaluate the range of motion to see if there are any limitations in movement.

Provocative tests (Cluster of Laslett)

These tests stress the SI joint to reproduce the patient's familiar pain. A positive result in two or more tests is highly indicative of SI joint pain:

  • Distraction: Posterolateral pressure is applied to the anterior superior iliac spines.
  • Thigh Thrust: Posterior pressure is applied through the flexed femur to stress the SI joint.
  • Compression: Vertical thrusts are applied to the iliac crest while the patient lies on the asymptomatic side.
  • Sacral Thrust: Anterior thrusts are applied over the sacrum.

Additional assessments

Identify the source of pain in the center or edges of the back to determine the appropriate treatment. If the pain is suspected to originate from the sacroiliac (SI) joint, consider administering temporary relief through anesthetic injections guided by imaging techniques.

Printable Cluster of Laslett

Download this Cluster of Laslett guide to improve your assessment of sacroiliac joint dysfunction in patients.

What is the Cluster of Laslett test?

The Cluster of Laslett is a set of SI pain provocation tests designed to diagnose sacroiliac joint pain and dysfunction accurately. This tool identifies painful or painful sacroiliac joints and differentiates them from other sources of buttock pain or chronic lower back pain. Applying a series of tests enhances diagnostic accuracy for SI by detecting sacroiliac joint pain pathology while addressing bias and applicability concerns.

Key components include:

  • Distraction: The patient lies on their back with legs extended while the clinician applies outward pressure to separate the sacroiliac joints, assessing for pain provocation.
  • Thigh thrust: Applying posterior pressure to the thigh with the hip flexed at 90°, detecting pain based on discomfort.
  • Compression: The patient is side-lying while pressure is applied downward on the uppermost iliac crest to compress the sacroiliac joints, assessing for sacroiliac pain.
  • Sacral thrust: With the patient prone, a force is applied to the sacrum's midline to provoke pain in the sacroiliac joint region.
  • Gaenslen: In a prone position, one leg is extended off the examination table while the other flexes to the chest. The clinician applies pressure to both legs to create rotational stress across the sacroiliac joints.

A positive test result is typically indicated if three or more of these tests provoke familiar pain, increasing the positive posterior probability of diagnosing pain. This approach helps pain physicians decide on further interventions, such as SI joint blocks. 

What are the possible results and interpretations?

Results of these pain provocation tests are considered positive if they replicate the patient's physician's usual pain and are used to assess the presence of sacroiliac joint pathology. Here’s how to interpret the findings of clinical tests:

  • Positive: Two or more positive results among these tests increase the diagnostic accuracy, suggesting joint pain.
  • Negative: Fewer than two positive tests typically suggest that pain is unlikely.

Interpretations based on these results can guide further clinical decision-making:

  • High positive likelihood ratio: Indicates a substantial likelihood of sacroiliac joint dysfunction when tests are positive.
  • Negative likelihood ratio: A negative test result significantly lowers the probability of the condition.
  • Diagnostic validity: Studies have shown varying sensitivity and specificity, reinforcing the need for a comprehensive assessment.

Combining these tests can improve the diagnostic odds ratio, aiding physical therapy and treatment planning. However, clinicians should be aware of the potential for false favorable rates and ensure a thorough physical examination and possibly confirmatory sacroiliac joint blocks if the diagnosis remains uncertain. 

How does our Cluster of Laslett test template work?

The template provides clinicians with a structured and efficient approach for diagnosing SI joint dysfunction. The purpose is to streamline testing while ensuring consistent data collection, diagnosis, and treatment planning. 

A step-by-step guide to how it functions:

  1. Record the patient's name, age, gender, medical history, and primary complaint. This helps identify specific risk factors that may impact the assessment.
  2. Key considerations for ensuring the patient’s safety and testing reliability are outlined. Follow them for better results. 
  3. The core of the template is the series of sacroiliac pain provocation tests. Each test has clearly defined steps to ensure repeatability. Results are recorded as "Positive" or "Negative."
  4. Compile the outcomes of each test and determine if the patient has a positive diagnosis based on the Cluster of Laslett criteria (two or more positive results). If fewer than two tests are positive, further testing may be needed to diagnose the source of pain.
  5. Document observations, patient reactions, or upcoming diagnostic plans or specialist referrals.
  6. The clinician's name, credentials, and signature should be noted to validate the testing process and document the date.

Cluster of Laslett test example (sample)

Upgrade your medical practice with our complimentary Cluster of Laslett test template. Designed for efficiency and accuracy, this aids in diagnosing sacroiliac joint dysfunction through straightforward testing procedures. 

It emphasizes patient safety and dependable outcomes, simplifying treatment planning and data collection. This tool can enhance your diagnostic approach, ensuring a smoother process. 

By downloading our free template today, you gain access to a valuable resource that streamlines the identification of this condition, facilitating better patient care and treatment outcomes. Make the most of this opportunity to improve your diagnostic strategies.

Download this free Cluster of Laslett Test example here

Cluster of Laslett test example (sample)

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What is the cause of sacroiliitis?
What is the cause of sacroiliitis?

Commonly asked questions

What is the cause of sacroiliitis?

Sacroiliitis is often caused by inflammation due to injury, arthritis, pregnancy, infection, or prolonged stress on the SI joint.

Can SIJ dysfunction be cured?

Sacroiliac joint (SIJ) dysfunction can often be managed with treatment, including physical therapy, medication, or injections, though some cases may require ongoing care.

Is walking good for sacroiliac joint pain?

Yes, walking can be helpful as a low-impact activity that promotes movement and reduces stiffness, but it's important not to overexert yourself.

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