Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 4 complete abstracts (884 words), 10 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
Inflammation of the sacroiliac joint. It is characterized by lower back pain, especially upon walking, fever, uveitis; psoriasis; and decreased range of motion. Many factors are associated with and cause sacroiliitis including infection; injury to spine, lower back, and pelvis; degenerative arthritis; and pregnancy.
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Sacroiliitides; Septic Sacroiliitis; Sacroiliitides, Septic; Sacroiliitis, Septic; Septic Sacroiliitides; Pyogenic Sacroiliitis; Pyogenic Sacroiliitides; Sacroiliitides, Pyogenic.
Where it fits in the MeSH classification
- Broader topics
- Arthritis
- See also
- Sacroiliac Joint
Related concepts
- Sacroiliac Joint
- Uveitis
- Psoriasis
- Osteoarthritis
Research landscape
PubMed indexes 899 records tagged with the MeSH heading “Sacroiliitis” (counts retrieved 2026-11-04). 404 of them (44.9%) were published from 2020 onward, and the busiest period so far is 2010-2019 with 492 records.
Reviews account for 124 records (13.8%) and meta-analyses for 4. Randomized controlled trials number 16 (1.8%) as a share of all records on the topic. Randomized trials make up only a small share of this literature, so much of what is known comes from laboratory, observational or descriptive work.
Show the data
| Period | Records |
|---|---|
| through 1999 | 0 |
| 2000-2009 | 4 |
| 2010-2019 | 492 |
| 2020 onward | 404 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 124 | 13.8% |
| Meta-analyses | 4 | 0.4% |
| Randomized controlled trials | 16 | 1.8% |
Method: PubMed query "Sacroiliitis"[MeSH Terms] with publication-type and date filters, retrieved 2026-11-04.
Reading the evidence in bones, joints, muscles and skin
Joint, bone, muscle and skin conditions are often judged by pain scores, function questionnaires, imaging or photographs, and symptoms can fluctuate, so placebo response and natural improvement matter. Imaging changes are common in people without symptoms. Nothing on this page is advice about treatment. Check how outcomes were measured, whether the comparison group received a placebo or usual care, and how long the benefit lasted.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| Deep learning for detection of radiographic sacroiliitis: achieving expert-level performance | 2021 | Research article Design not recorded in structured metadata | 64 | cc by PMID 33832519 · DOI · PMC8028815 |
| MRI in axial spondyloarthritis: understanding an 'ASAS-positive MRI' and the ASAS classification criteria | 2022 | Review article Design not recorded in structured metadata | 44 | cc by PMID 35199195 · DOI · PMC9283193 |
| Feasibility and reliability of the Spondyloarthritis Research Consortium of Canada sacroiliac joint inflammation score in children | 2018 | Research article Design not recorded in structured metadata | 34 | cc by PMID 29566735 · DOI · PMC5865339 |
| Comparative radiologic characteristics of isotretinoin-induced sacroiliitis and axial spondyloarthritis | 2026 | Research article Design not recorded in structured metadata | 1 | cc by PMID 42012625 · DOI · PMC13588890 |
Deep learning for detection of radiographic sacroiliitis: achieving expert-level performance [1]
Abstract reading summary — source excerpts
- Opening excerpt
- BackgroundRadiographs of the sacroiliac joints are commonly used for the diagnosis and classification of axial spondyloarthritis.
- Closing excerpt
- ConclusionDeep artificial neural networks enable the accurate detection of definite radiographic sacroiliitis relevant for the diagnosis and classification of axSpA.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (266 words)
BackgroundRadiographs of the sacroiliac joints are commonly used for the diagnosis and classification of axial spondyloarthritis. The aim of this study was to develop and validate an artificial neural network for the detection of definite radiographic sacroiliitis as a manifestation of axial spondyloarthritis (axSpA).MethodsConventional radiographs of the sacroiliac joints obtained in two independent studies of patients with axSpA were used. The first cohort comprised 1553 radiographs and was split into training (n = 1324) and validation (n = 229) sets. The second cohort comprised 458 radiographs and was used as an independent test dataset. All radiographs were assessed in a central reading session, and the final decision on the presence or absence of definite radiographic sacroiliitis was used as a reference. The performance of the neural network was evaluated by calculating areas under the receiver operating characteristic curves (AUCs) as well as sensitivity and specificity. Cohen's kappa and the absolute agreement were used to assess the agreement between the neural network and the human readers.ResultsThe neural network achieved an excellent performance in the detection of definite radiographic sacroiliitis with an AUC of 0.97 and 0.94 for the validation and test datasets, respectively. Sensitivity and specificity for the cut-off weighting both measurements equally were 88% and 95% for the validation and 92% and 81% for the test set. The Cohen's kappa between the neural network and the reference judgements were 0.79 and 0.72 for the validation and test sets with an absolute agreement of 90% and 88%, respectively.ConclusionDeep artificial neural networks enable the accurate detection of definite radiographic sacroiliitis relevant for the diagnosis and classification of axSpA.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 33832519 · DOI · PMC8028815
MRI in axial spondyloarthritis: understanding an 'ASAS-positive MRI' and the ASAS classification criteria [2]
Abstract reading summary — source excerpts
- Opening excerpt
- In 2009, the Assessment of SpondyloArthritis international Society (ASAS) published a definition of 'active sacroiliitis on magnetic resonance imaging (MRI) for classification of axial spondyloarthritis'.
- Closing excerpt
- The article also contains guidance for an updated imaging protocol and interpretation of images including typical imaging findings, differential diagnosis, and common pitfalls.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (180 words)
In 2009, the Assessment of SpondyloArthritis international Society (ASAS) published a definition of 'active sacroiliitis on magnetic resonance imaging (MRI) for classification of axial spondyloarthritis'. This new definition of an 'ASAS-positive MRI' was integral to new classification criteria for axial spondyloarthritis that were published in the same year. The ASAS MRI definition had the considerable advantage of simplicity and the definition gained popularity as guidance for interpreting MRI of the sacroiliac joints in clinical practice. However, classification criteria are not designed for use in clinical practice with the consequence that overreliance on the presence of bone marrow edema, which is the principal determinant of an 'ASAS-positive MRI', may result in a tendency to overcall inflammatory sacroiliitis in the clinical setting. This article aims to inform the reader about the rationale behind the ASAS definition of a positive MRI and ASAS classification criteria, their proper use in research and why they should not be used in clinical practice. The article also contains guidance for an updated imaging protocol and interpretation of images including typical imaging findings, differential diagnosis, and common pitfalls.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 35199195 · DOI · PMC9283193
Feasibility and reliability of the Spondyloarthritis Research Consortium of Canada sacroiliac joint inflammation score in children [3]
Abstract reading summary — source excerpts
- Opening excerpt
- BackgroundPublished methods for quantification of magnetic resonance imaging (MRI) evidence of inflammation in the sacroiliac joint lack validation in pediatric populations.
- Closing excerpt
- The ICC improved with additional calibration and reading exercises, for both experienced and inexperienced readers.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (222 words)
BackgroundPublished methods for quantification of magnetic resonance imaging (MRI) evidence of inflammation in the sacroiliac joint lack validation in pediatric populations. We evaluated the reliability and construct validity of the Spondyloarthritis Research Consortium of Canada (SPARCC) sacroiliac joint inflammation score (SIS) in children with suspected or confirmed juvenile spondyloarthritis (JSpA).MethodsThe SPARCC SIS measures the presence, depth, and intensity of bone marrow inflammation on MRI through the cartilaginous part of the joint. Six readers blinded to clinical details except age, participated in two reading exercises, each preceded by a calibration exercise. Inter-observer reliability was assessed using intraclass correlation coefficients (ICCs) and for pre-specified acceptable reliability the inraclass correlation coefficient (ICC) was > 0.8.ResultsThe SPARCC SIS had face validity and was feasible to score in pediatric cases in both reading exercises. Cases were mostly male (64%) and the median age at the time of imaging was 14.9 years. After calibration, the median ICC across all readers for the SIS total score was 0.81 (IQR 0.71-0.89). SPARCC SIS had weak correlation with disease activity (DA) as measured by the JSpADA (r = - 0.12) but discriminated significantly between those with and without elevated C-reactive protein (p = 0.03).ConclusionThe SPARCC SIS was feasible to score and had acceptable reliability in children. The ICC improved with additional calibration and reading exercises, for both experienced and inexperienced readers.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 29566735 · DOI · PMC5865339
Comparative radiologic characteristics of isotretinoin-induced sacroiliitis and axial spondyloarthritis [4]
Abstract reading summary — source excerpts
- Opening excerpt
- BackgroundSacroiliitis is a major cause of inflammatory low back pain in young adults and a key feature of spondyloarthritis (SpA), but it may also occur with infection, pregnancy, or drug exposure.
- Closing excerpt
- The present results may assist clinicians and radiologists in distinguishing between these two conditions in clinical practice.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (216 words)
BackgroundSacroiliitis is a major cause of inflammatory low back pain in young adults and a key feature of spondyloarthritis (SpA), but it may also occur with infection, pregnancy, or drug exposure. Isotretinoin, widely used for severe acne, can rarely induce sacroiliitis.AimThis study aimed to compare the MRI characteristics of isotretinoin-induced sacroiliitis with those of axial spondyloarthritis (axSpA).MethodsThe study population consisted of 68 patients, comprising 28 with isotretinoin-induced sacroiliitis (median age 24 years; 5 males) and 40 with axSpA (median age 30 years; 26 males). MRI scans were assessed for active inflammatory lesions (bone marrow edema, synovitis, capsulitis, enthesitis) and early structural lesions (erosion, fat metaplasia). SPARCC scoring was performed using the standardized 0-72 system. Ankylosis and sclerosis were not included as it was absent in both groups. Group comparisons were conducted using the Mann-Whitney U test, chi-square test, or Fisher's exact test.ResultsWhile isotretinoin-induced sacroiliitis showed a purely inflammatory pattern without structural lesions, patients with axSpA exhibited both active inflammatory and structural lesions. Erosions and fat metaplasia were observed exclusively in axSpA patients (p ConclusionIsotretinoin-induced and axSpA sacroiliitis exhibit distinct MRI characteristics. Erosions and fat metaplasia are specific markers of axSpA, whereas isotretinoin-induced sacroiliitis represents a reversible, non-destructive inflammatory process. The present results may assist clinicians and radiologists in distinguishing between these two conditions in clinical practice.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42012625 · DOI · PMC13588890
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article Defining active sacroiliitis on MRI for classification of axial spondyloarthritis: update by the ASAS MRI working group [5]
- Research article 2019 American College of Rheumatology/Arthritis Foundation Guideline for the Treatment of Juvenile Idiopathic Arthritis: Therapeutic Approaches for Non-Systemic Polyarthritis, Sacroiliitis, and Enthesitis [6]
- Research article 2019 American College of Rheumatology/Arthritis Foundation Guideline for the Treatment of Juvenile Idiopathic Arthritis: Therapeutic Approaches for Non-Systemic Polyarthritis, Sacroiliitis, and Enthesitis [7]
- Research article Review: Nonradiographic axial spondyloarthritis: new definition of an old disease? [8]
- Research article Axial involvement in psoriatic arthritis: An update for rheumatologists [9]
- Research article Classification criteria for psoriatic arthritis and ankylosing spondylitis/axial spondyloarthritis [10]
References
- Bressem KK, Vahldiek JL, Adams L, Niehues SM, Haibel H, Rodriguez VR, et al.. Deep learning for detection of radiographic sacroiliitis: achieving expert-level performance. . 2021. PMID 33832519 · DOI · PMC8028815
- Diekhoff T, Lambert R, Hermann KG. MRI in axial spondyloarthritis: understanding an 'ASAS-positive MRI' and the ASAS classification criteria. . 2022. PMID 35199195 · DOI · PMC9283193
- Weiss PF, Maksymowych WP, Lambert RG, Jaremko JL, Biko DM, Paschke J, et al.. Feasibility and reliability of the Spondyloarthritis Research Consortium of Canada sacroiliac joint inflammation score in children. . 2018. PMID 29566735 · DOI · PMC5865339
- Demirci MG, Savas NY, Kudas O, Aslan M, Savas T, Yildirim FE, et al.. Comparative radiologic characteristics of isotretinoin-induced sacroiliitis and axial spondyloarthritis. . 2026. PMID 42012625 · DOI · PMC13588890
- Lambert RG, Bakker PA, van der Heijde D, Weber U, Rudwaleit M, Hermann KG, et al.. Defining active sacroiliitis on MRI for classification of axial spondyloarthritis: update by the ASAS MRI working group. Ann Rheum Dis. 2016. PMID 26768408 · DOI
- Ringold S, Angeles-Han ST, Beukelman T, Lovell D, Cuello CA, Becker ML, et al.. 2019 American College of Rheumatology/Arthritis Foundation Guideline for the Treatment of Juvenile Idiopathic Arthritis: Therapeutic Approaches for Non-Systemic Polyarthritis, Sacroiliitis, and Enthesitis. Arthritis Care Res (Hoboken). 2019. PMID 31021516 · DOI · PMC6561125
- Ringold S, Angeles-Han ST, Beukelman T, Lovell D, Cuello CA, Becker ML, et al.. 2019 American College of Rheumatology/Arthritis Foundation Guideline for the Treatment of Juvenile Idiopathic Arthritis: Therapeutic Approaches for Non-Systemic Polyarthritis, Sacroiliitis, and Enthesitis. Arthritis Rheumatol. 2019. PMID 31021537 · DOI · PMC6561114
- Sieper J, van der Heijde D. Review: Nonradiographic axial spondyloarthritis: new definition of an old disease?. Arthritis Rheum. 2013. PMID 23233285 · DOI
- Poddubnyy D, Jadon DR, Van den Bosch F, Mease PJ, Gladman DD. Axial involvement in psoriatic arthritis: An update for rheumatologists. Semin Arthritis Rheum. 2021. PMID 34198146 · DOI
- Rudwaleit M, Taylor WJ. Classification criteria for psoriatic arthritis and ankylosing spondylitis/axial spondyloarthritis. Best Pract Res Clin Rheumatol. 2010. PMID 21035082 · DOI
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-11-04; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-11-04.
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Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.