A new sacroiliac test: distraction of the PSIS

Critically Appraised Topic:
A New Sacroiliac Distraction Test of the PSIS.
Appraiser: Jerry Hesch, MHS, PT
Date: June 04, 2014

  Clinical Question: Is there evidence to support the use of a distraction test applied directly to the posterior bony pelvis(PSIS) as a pain provocation maneuver for sacroiliac joint mediated pain?

Clinical Bottom Line: The posterior superior iliac spine distractions test (PSIS-DT) had high sensitivity, specificity, and accuracy. These findings contrast distinctly with the other sacroiliac joint (SIJ) pain provocation tests which are in common use; including the thigh-thrust test, Gaenslen’s maneuver, Faber test, and pelvic compression and distraction tests. The PSIS-DT appears to have clinical utility is easy to perform and also appears to be very safe. Based on these encouraging results additional research via prospective, blinded, multi-investigator trials appears to be warranted. In the interim, clinical application will yield additional empirical data.

  Citation: Werner, C.M.L., Hoch, A., Gautier, L., Konig, M.A., Simmen, H.P., Osterhoff, G. (2013). Distraction test of the posterior superior iliac spine (PSIS) in the diagnosis of sacroiliac joint arthropathy. BioMed Central Surgery, 13(52). doi:  10.1186/1471-2482-13-52

  Summary of Study:

Study Design: A retrospective study in a case control design was utilized.

Sample: All patients from a clinical sample of convenience ≥ 18-years of age with low back pain related to the study. Exclusion criteria included spondylitis neuropathies, ridiculous of these, trauma, malignancies, that pathology, dementia, pregnancy, and allergy to injection medication. The control group consisted of 32 volunteers (64 sacroiliac joints) of age40-years =/- 15-years without a history of low back pain or pelvic pain participated.

Intervention/Procedure: Both groups were evaluated with a novel test named Distraction Test of the PSIS, which consists of a medial to lateral impulse with the examiner’s thumb against the medial border of the posterior superior iliac spines (PSIS) performed with the subject standing or in prone. The test incident positive if it reproduced familiar or novel pain in the intervention group.

Within a maximum of two weeks after manual examination the intervention group received an injection by one of four non-blinded investigators. The injection was performed with fluoroscopy guidance to the sacroiliac joint on the symptomatic side(s), consisting of dye, a local anesthetic and a steroid. Traditional sacroiliac pain provocation tests were also performed in both groups consisting of the thigh-thrust test, Gaenslen’s maneuver, Faber test, and pelvic compression and distraction tests.

Outcome Measures: Just prior to and after injection patients filled out a visual analog scale and a report of ≥ 50% pain relief within 15 to 30 minutes was interpreted as indicative of intra-articular sacroiliac arthropathy.

Data Analysis and Results: SPSS statistical software for Windows® 21.0 (SPSS Chicago, IL, USA) was utilized.

11% of the control group had a positive response to the PSIS-DT. In the intervention group 100% who had a positive response to injection were identified with the PSIS-DT. 

In the intervention group sensitivity was 100%, specificity was 89%, accuracy of the test was 94%, and positive prediction value (PPV) was 90% and negative prediction value (NPV) was 100% with an infinitive odds ratio.

In contrast, the traditional tests had much lower sensitivity ranging from 23-34%. Specificity exceeded 90%, PPV exceeded 80%, while NPV averaged 57-60%.

Appraisal: While traditional tests have significant heterogeneity and inconsistency or systematic review the novel PSIS-DT was found to have high sensitivity and specificity and therefore very good accuracy within a population of patients with confirmed symptomatic sacroiliac arthropathy. In contrast with traditional tests this test is rather easy to perform and does not appear to impart forces through proximal structures such as the lumbar spine and hip. Direct force application occurs in an anatomical area of well-documented sensitivity in this patient population. The above reasons encourage continued clinical and research exploration of this novel test.

The following points provide reflection and consideration for future studies.

• The Gaenslen’s and thigh thrust tests were combined for data analysis without explanation.
• Only one investigator performed the tests with the control group. This serves as a threat to error rate an assumption of statistical tests and reliability.
• A pressure algometer could be utilized to demonstrate consistent force application using blinded examiners with randomized mix of intervention and control groups.
• Reporting of gender and parous status is relevant to this diagnostic group.
• Greater detail on the exclusion process or hip pathologies is warranted.
• Replacing the fluroscopy with CT-guided infiltration would allow the identification of any cases with extravasation of pain medication reducing false positive responses.
• Duration of symptoms in the intervention group was not recorded.
• The innervation of the soft tissues proximal to the PSIS an example of construct under-representation and more in-depth exploration of the literature would strengthen the internal validity.
• Literature on inter-tester and intra-tester reliability for PSIS palpation should be presented impacting internal and external validity.
• Be rationale for performing the PSIS-DT in standing or prone begs explanation.

Conclusion: The posterior superior iliac spine distractions test (PSIS-DT) had high sensitivity, specificity, and accuracy. These findings contrast distinctly with the other sacroiliac joint (SIJ) pain provocation tests which are in common use; including the thigh-thrust test, Gaenslen’s maneuver, Faber test, and pelvic compression and distraction tests. The PSIS-DT appears to have clinical utility is easy to perform and also appears to be very safe.