[Diagnosis and classification of axial spondyloarthritis (axSpA) - the current status]. / Diagnostik und Klassifikation der axialen Spondyloarthritis (axSpA) ­ der aktuelle Stand.

Axial spondyloarthritis (axSpA) is an inflammatory rheumatic disease typically characterized by inflammatory back pain (IBP). The term axSpA has largely replaced the long-used term ankylosing spondylitis (AS). IBP is caused by inflammation in the axial skeleton, with the sacroiliac joints (SIJ) being particularly frequently affected initially. The spine is usually added in later stages, which is then increasingly characterized structurally by the formation of new bone. The overall concept of spondyloarthritis includes other disease manifestations such as uveitis, psoriasis and colitis and comorbidities such as cardiovascular disease and osteoporosis.The ASAS classification criteria for axSpA, in place since 2009, have replaced the 1984 modified New York criteria. In the former, in addition to conventional X-rays, changes in the SIJ detected by magnetic resonance imaging (MRI) and also the detection of HLA B27 have, for the first time, played a role. It is important to note that these are not diagnostic criteria, as they do not exist. This paper outlines 10 points that should be considered when making a diagnosis.

Does sacroiliitis is a mandatory criterion for enthesitis-related arthritis diagnosis? / ¿La sacroilitis es un criterio obligatorio para el diagnóstico de artritis relacionada con entesitis?

Introduction and objectives: Magnetic resonance imaging (MRI) sensitivity and specificity seem to be less studied in enthesitis-related arthritis (ERA). We aimed to determine the ability of sacroiliac MRI to diagnose ERA patients. Materials and methods: We conducted a retrospective study including 44 patients with juvenile idiopathic arthritis (JIA). Each patient had a sacroiliac joint MRI. We divided patients into two groups: G1 patients with ERA and G2 patients with non-ERA subtype. Results: ERA was noted in 61% of the cases. Sacroiliac joints were painful in 15 patients (34%). MRI was normal in 25 patients (57%) (G1:11 versus G2:14) and showed bone marrow edema in the sacroiliac joints in 19 patients (34%) (G1=16 versus G2=3, p=0.005). Sacroiliac joints MRI's sensitivity and specificity in the ERA diagnosis were 61.54% and 82.35%, respectively. Positive and negative predictive values were 84.21% and 58.33%, respectively. Furthermore, sacroiliac joint pain in the clinical examination was able to predict sacroiliac bone edema in MRI with an odds ratio of 6.8 (95% CI 1.68–28.09; p=0.006). Conclusion: Our study showed that sacroiliac joint MRI has good specificity and positive predictive value in the diagnosis of ERA patients among JIA patients. This underlines the usefulness of sacroiliac joint MRI in the early diagnosis of ERA patients.(AU)

Introducción y objetivos: La sensibilidad y especificidad de la resonancia magnética parecen estar menos estudiadas en la artritis relacionada con entesitis (ERA). Nuestro objetivo era determinar la capacidad de la resonancia magnética de la articulación sacroilíaca para diagnosticar pacientes con ERA. Materiales y métodos: Realizamos un estudio retrospectivo que incluyó a 44 pacientes con artritis idiopática juvenil (AIJ). A cada paciente se le realizó una resonancia magnética de la articulación sacroilíaca. Dividimos a los pacientes en dos grupos: G1: pacientes con ERA y G2: pacientes con subtipo no ERA. Resultados: Se observó ERA en 61% de los casos. Las articulaciones sacroilíacas resultaron dolorosas en 15 pacientes (34%). La resonancia magnética fue normal en 25 pacientes (57%) (G1:11 vs. G2:14) y mostró edema de médula ósea en las articulaciones sacroilíacas en 19 pacientes (34%) (G1=16 vs. G2=3, p=0,005). La sensibilidad y especificidad de la resonancia magnética de articulaciones sacroilíacas en el diagnóstico de ERA fueron de 61,54 y 82,35%, respectivamente. Los valores predictivos positivos y negativos fueron 84,21 y 58,33%, respectivamente. Además, el dolor en la articulación sacroilíaca en el examen clínico fue capaz de predecir el edema del hueso sacroilíaco en la resonancia magnética con un odds ratio de 6,8 (IC 95%: 1,68 a 28,09; p=0,006). Conclusión: Nuestro estudio demostró que la resonancia magnética de la articulación sacroilíaca tiene buena especificidad y valor predictivo positivo en el diagnóstico de pacientes con ERA entre pacientes con AIJ. Esto subraya la utilidad de la resonancia magnética de la articulación sacroilíaca en el diagnóstico temprano de pacientes con ERA.(AU)

Does sacroiliitis is a mandatory criterion for enthesitis-related arthritis diagnosis?

INTRODUCTION AND OBJECTIVES: Magnetic resonance imaging (MRI) sensitivity and specificity seem to be less studied in enthesitis-related arthritis (ERA). We aimed to determine the ability of sacroiliac MRI to diagnose ERA patients. MATERIALS AND METHODS: We conducted a retrospective study including 44 patients with juvenile idiopathic arthritis (JIA). Each patient had a sacroiliac joint MRI. We divided patients into two groups: G1 patients with ERA and G2 patients with non-ERA subtype. RESULTS: ERA was noted in 61% of the cases. Sacroiliac joints were painful in 15 patients (34%). MRI was normal in 25 patients (57%) (G1:11 versus G2:14) and showed bone marrow edema in the sacroiliac joints in 19 patients (34%) (G1=16 versus G2=3, p=0.005). Sacroiliac joints MRI's sensitivity and specificity in the ERA diagnosis were 61.54% and 82.35%, respectively. Positive and negative predictive values were 84.21% and 58.33%, respectively. Furthermore, sacroiliac joint pain in the clinical examination was able to predict sacroiliac bone edema in MRI with an odds ratio of 6.8 (95% CI 1.68-28.09; p=0.006). CONCLUSION: Our study showed that sacroiliac joint MRI has good specificity and positive predictive value in the diagnosis of ERA patients among JIA patients. This underlines the usefulness of sacroiliac joint MRI in the early diagnosis of ERA patients.

Extra-articular screw placement strategy in Stoppa approach based on three-dimensional reconstruction model.

The study aimed to explore an extra-articular screw placement strategy in Stoppa approach. Radiographic data of patients who underwent pelvic computed tomography from January 2016 to June 2017 were imported into Materiaise's interactive medical image control system software for three-dimensional reconstruction. Superior and lower margins of acetabulum and ipsilateral pelvic brim could be observed simultaneously through inlet-obturator view. A horizontal line from superior acetabular margin intersected pelvic brim at point "A" and another vertical line from lower margin intersected pelvic brim at point "B" were drawn, respectively. Lengths form sacroiliac joint to "A" (a), "A" to "B" (b), and "B" to pubic symphysis (c) were measured. Patients were divided into four groups depending on gender and side difference of measured hemi-pelvis: male left, male right, female left, and female right. Lengths of adjacent holes (d) and spanning different holes (e) of different plates were also measured. Mean lengths of a, b, c in four groups were 40.94 ± 1.85 mm, 40.09 ± 1.93 mm, 41.78 ± 3.62 mm, and 39.77 ± 2.23 mm (P = 0.078); 40.65 ± 1.58 mm, 41.48 ± 1.64 mm, 40.40 ± 1.96 mm, and 40.66 ± 1.70 mm (P = 0.265); 57.03 ± 3.41 mm, 57.51 ± 3.71 mm, 57.84 ± 4.40 mm, and 59.84 ± 4.35 mm (P = 0.165), respectively. Mean d length of different plates was 12.23 mm. Average lengths spanning 1, 2, 3 and 4 holes were 19.33 mm, 31.58 mm, 43.80 mm, and 55.93 mm. Our data showed that zones a and c could be safely inserted three and four screws. Penetration into hip joint could be avoided when vacant 3-hole drilling was conducted in zone b. Fracture line in zone b could serve as a landmark for screw placement.

Critical distance of the sacroiliac joint for open reduction using screw fixation for traumatic sacroiliac joint diastasis: a retrospective study.

BACKGROUND: Osteosynthesis for sacroiliac joint (SIJ) diastasis using an iliosacral screw (ISS) and a trans-iliac-trans-sacral screw (TITSS) can be performed using a closed or an open method. However, no clear indication for open reduction has been established. METHODS: Data on patients with unilateral traumatic SIJ diastasis who underwent ISS and TITSS fixation were retrospectively collected and separated into groups according to the reduction method: closed reduction group (C group) and open reduction group (O group). Demographic data and perioperative image assessments were compared between the groups. The critical distance of the SIJ was identified to elucidate the indication for open reduction of the diastatic SIJ. RESULTS: Fifty-six patients met the inclusion criteria over a 3-year period. There was no significant difference in the reduction quality of pelvic ring injuries between the groups, according to Matta's and Lefaivre's criteria. The improvement in the SIJ distance was significantly greater in the O group than in the C group in the axial plane on multiplanar computed tomography (p = 0.021). This model predicted that a difference of > 3.71 mm between the injured and healthy SIJ was a recommended indication for open reduction, with an area under the curve of 0.791 (95% confidence interval 0.627-0.955, p = 0.004). CONCLUSIONS: Open reduction for SIJ diastasis might achieve better reduction quality than does closed reduction in the axial plane in selected cases. When the difference between the injured and healthy SIJ was wider than 3.71 mm, open reduction was recommended for satisfactory radiological outcomes.

Diagnostic accuracy in axial spondyloarthritis: a systematic evaluation of the role of clinical information in the interpretation of sacroiliac joint imaging.

OBJECTIVES: Radiography and MRI of the sacroiliac joints (SIJ) are relevant for the diagnosis and classification of patients with axial spondyloarthritis (axSpA). This study aimed to evaluate the impact of clinical information (CI) on the accuracy of imaging interpretation. METHODS: Out of 109 patients referred because of suspicion of axSpA with complete imaging sets (radiographs and MRI of SIJ), 61 were diagnosed with axSpA (56%). Images were independently evaluated by three radiologists in four consecutive reading campaigns: radiographs and radiographs+MRI without and with CI including demographic data, SpA features, physical activity and pregnancy. Radiographs were scored according to the modified New York criteria, and MRIs for inflammatory and structural changes compatible with axSpA (yes/no). The clinical diagnosis was taken as reference standard. The compatibility of imaging findings with a diagnosis of axSpA (precision) before and after the provision of CI and radiologists' confidence with their findings (0-10) were evaluated. RESULTS: The precision of radiographs evaluation without versus with CI increased from 70% to 78% (p=0.008), and for radiographs+MRI from 81% to 82% (p=1.0), respectively. For CR alone, the sensitivity and specificity of radiologic findings were 51% and 94% without and 60% and 100% with CI, while, for radiographs+MRI, they were 74% and 90% vs 71% and 98%, respectively. The diagnostic confidence of radiologists increased from 5.2±1.9 to 6.0±1.7 with CI for radiographs, and from 6.7±1.6 to 7.2±1.6 for radiographs+MRI, respectively. CONCLUSION: The precision, specificity and diagnostic confidence of radiologic evaluation increased when CI was provided.

Clinical and imaging outcomes of different phenotypes of axial spondyloarthritis: 5-year analysis of the DESIR cohort.

OBJECTIVES: To compare the long-term outcomes of three phenotypes of axial SpA (axSpA). METHODS: Patients with a clinical diagnosis of axSpA from the DESIR cohort were grouped into three phenotypes at baseline: 'Pure axSpA' ('Axial'), 'axSpA with peripheral signs' ('IBP+Peripheral') and 'axSpA at risk' ('At risk') by latent class analysis. Clinical and imaging data were collected up to 5 years. Clinical outcomes, measured in each visit, included disability (BASFI) and quality of life (QoL; SF36). Imaging outcomes included inflammatory and structural lesions on MRI and radiographs of spine and SIJ. The association between phenotype membership at baseline and each outcome was tested in multivariable GEE models. RESULTS: In total, 576 patients with axSpA were included. 'At risk' patients had worse disability and QoL than 'Axial' patients over time. For instance, 'At risk' patients had on average 0.4 more points in BASFI over time than 'Axial' patients [ß (95 % CI): 0.4 (0.2; 0.7)]. This difference was mostly noted in female patients who were HLA-B27 positive. In addition, the difference between the 'At risk' and 'Axial' phenotypes was higher in patients receiving bDMARDs than in those not (ß=0.6 vs 0.5), since BASFI improved more in 'Axial' (∆BASFI: -1.3) than in 'At risk' (∆BASFI: -0.9) treated patients. There were no differences in disability and QoL between 'Axial' and 'IBP+Peripheral' patients. Imaging outcomes were worse in the 'Axial' phenotype than in the others over time. CONCLUSION: Patients with 'axSpA at risk' show worse self-reported outcomes over time and are less likely to benefit from anti-inflammatory treatment than those with a classical axSpA phenotype.

Do Patients Accurately Recall Pain Levels Following Sacroiliac Joint Steroid Injection? A Cohort Study of Recall Bias in Patient-reported Outcomes.

BACKGROUND: Sacroiliac joint (SIJ) injections are crucial in the diagnostic toolkit for evaluating SIJ pathology. Recall bias is an important component in patient-reported outcomes that has not been well studied in SIJ injection. OBJECTIVE: The purpose of this study was to characterize the accuracy, direction, and magnitude of pain level recall bias following SIJ steroid injection and study the factors that affect patient recollection. STUDY DESIGN: Prospective cohort study. SETTING: Level 1 academic medical center. METHODS: Using standardized questionnaires, baseline Numeric Rating Scale (NRS-11) scores were recorded for patients undergoing SIJ steroid injections at preinjection, at 4 hours postinjection, and at 24 hours postinjection. At a minimum of 2 weeks postinjection, patients were asked to recall their preinjection, 4-hour, and 24-hour postinjection NRS-11 scores. Actual and recalled NRS-11 scores were compared using paired t tests for each time interval. Multivariable linear regression was used to identify factors that correlated with consistent recall. RESULTS: Sixty patients with a mean age of 66 years (65% women) were included. Compared to their preinjection pain score, patients showed considerable improvement at both 4 hours (mean difference [MD] = 3.28; 95% CI, 2.68 - 3.89), and 24 hours (MD = 3.23; 95% CI, 2.44 - 4.03) postinjection. Patient recollection of preinjection symptoms was more severe than actual (MD = 0.65; 95% CI, 0.31 - 0.99). Patient recollection of symptoms was also more severe than actual at 4 hours (MD = 0.50; 95% CI .04 - 1.04) as well as at 24 hours postinjection (MD = 0.80; 95% CI, 0.16 - 1.44). The magnitude of recall bias was mild and did not exceed the minimal clinically important difference. There was a moderate correlation between actual and recalled pain levels when comparing preinjection with the 4-hour postinjection NRS-11 score (correlation coefficient [r] =0.64; P < 0.001) and moderate correlation when comparing preinjection with the 24-hour postinjection NRS-11 score (r = 0.62; P < 0.001). Linear regression models showed that at preinjection, patients with a lower body mass index and the presence of coexisting psychiatric diagnoses were better at recalling their pain (P < 0.05). Patients with a higher body mass index also experienced less pain relief when comparing preinjection with the 4-hour postinjection NRS-11 score (P < 0.05). LIMITATIONS: Recall pain scores were obtained via telephone surveys, which can lead to interview bias. One patient died, and 3 were lost to follow-up. We did not control for patient use of adjunctive pain relief modalities, which may modulate the overall response to injection. SIJ injections can also be diagnostic, so some patients may not have shared the same indication for injection or pain-generating diagnosis. CONCLUSIONS: Patients had favorable pain level responses to their SIJ steroid injection for both actual and recall surveys. Although patients demonstrated poor recall of absolute pain scores at preinjection, 4-hour postinjection, and 24-hour postinjection, they demonstrated robust recall of their net pain score improvement at both 4- and 24-hours postinjection. These findings suggest that there is utility in using patient recollection to describe the magnitude of pain relief following treatment for sacroiliac joint dysfunction.

Evaluation and Treatment of Sacroiliac Joint Pain in Patients with History of Vertebral Compression Fractures: A Retrospective Case Series.

BACKGROUND: Vertebral compression fractures (VCFs) can affect the entire spinopelvic complex and cause unpredictable patterns of back pain due to their effects on spinal tensegrity and biomechanical compensation. They can lead to significant morbidity and mortality in the aging population and are difficult to diagnose. We aimed to establish a relationship between VCFs and sacroiliac (SI) joint pain. OBJECTIVES: Demonstration of SI joint (SIJ) pain relief at up to 6 months after kyphoplasty (KP) in patients with VCFs and diagnosed SI dysfunction. STUDY DESIGN: Retrospective study. SETTING: All patients were from a private chronic pain and orthopedics practice in the northeastern United States. METHODS: Fifty-one patients with VCFs diagnosed through imaging and SIJ dysfunction diagnosed through 2 diagnostic SIJ blocks who had failed conservative management were considered for KP. Numeric Rating Scale (NRS 11) scores were recorded at the baseline, after each SIJ block, and at 4 weeks and then 6 months after KP. RESULTS: Forty-nine patients underwent KP. At 4 weeks after the procedure, there was an 84% average reduction in NRS scores from the baseline (P < 0.01). At 6 months after the procedure, there was an 80% reduction in NRS scores from the baseline (P < 0.01). LIMITATIONS: Larger sample sizes and a randomized control trial would be important steps in furthering the relationship between VCFs and SIJ. CONCLUSION: VCFs can cause a referred pain pattern to the SIJ that is best treated by KP for long-term management.

Study protocol for a prospective, randomized, multicenter trial to investigate the influence of peripheral nerve stimulation on patients with chronic sacroiliac joint syndrome (SILENCING).

BACKGROUND: The prevalence of sacroiliac joint pain (SIJP) is estimated to be 10-30% in patients with chronic low back pain. Numerous conservative and surgical treatment modalities for SIJP have been described with limited evidence regarding long-term pain relief. Spinal cord stimulation (SCS) is a well-established technique to treat patients with chronic low back pain. However, the effect on patients with SIJP is not consistent. Therefore, peripheral nerve stimulation (PNS) for chronic SIJP was implemented in experimental trials. Clinical data on PNS for SIJP is still lacking. The authors present a case series and a protocol for a prospective, multicenter study to determine the effect of PNS in patients with chronic intractable SIJP. METHOD: A multicenter, prospective randomized controlled trial was designed. Patients with chronic intractable SIJP will be recruited and randomized in a 4:3 ratio to either the peripheral nerve stimulation group or to the best medical treatment group. A total of 90 patients are planned to be enrolled (52 in the PNS group and 38 in the BMT group). Patients in the intervention group receive a percutaneous implantation of a unilateral or bilateral lead which is externalized for a trial phase for 3-14 days. After trial phase only patients with at least 50% reduction of pain receive an impulse generator for permanent stimulation. Regular visits for participants are planned on day 0, after 3 months (± 30 days), 6 months (± 30 days), and 12 months (± 60 days). The primary outcome measurements is the difference in Numeric Pain Rating Scale (NRS) between baseline and after 6 months. Secondary outcomes is improvement of pain associated disability (ODI) and improvement of health-related quality of life after 6 and 12 months. DISCUSSION: We have described the protocol for a prospective, multicenter, randomized trial evaluating the influence of PNS on patients with chronic sacroiliac joint syndrome. We believe that PNS on patients with chronic sacroiliac joint syndrome will show promising results regarding pain relief and quality of life in comparison to BMT after 12 months. The design of this trial promises high evidence in comparison to the data to date. TRIAL REGISTRATION: ClinicalTrials.gov, NCT05357300. Registered on April 26, 2022.

The bright Easter bunny sign: a useful aide-memoire on MRI for costotransverse joint inflammation in axial spondyloarthritis.

AIM: To assess the significance of the "bright Easter bunny" sign on magnetic resonance imaging (MRI) to indicate inflammatory costotransverse joint (CtJ) lesions to diagnose axial spondyloarthritis (ax-SpA). MATERIALS AND METHODS: Consecutive cases of patients with ax-SpA from a specialist rheumatology clinic were analysed retrospectively over two cohorts, between 2012-2014 and 2018-2020, to determine newly diagnosed patients under the Assessment of SpondyloArthritis international Society (ASAS) criteria. Biological naive adult patients who underwent spine MRI and sacroiliac imaging with full immunological work-up and a C-reactive protein reading within 3 months of the scan were included. Blinded images were reviewed by experienced musculoskeletal radiologists. RESULT: From the 1,284 cases that were identified, 40 cases met the inclusion criteria for this study. Seven out of the 40 cases (17.5%) identified inflammatory lesions at the CtJ with five (70%) showing concordance with the bright Easter bunny sign. CONCLUSION: The bright Easter bunny sign is concordant with inflammatory costotransverse enthesitis. This aide-memoire radiological sign is often on overlooked edge-of-field sections and this emphasises the need to ensure adequate coverage of the CtJ on spine MRI protocols as an important anatomical site of inflammatory change in ax-SpA assessment.

A literature review of biomechanical studies on physiological and pathological sacroiliac joints: Articular surface structure, joint motion, dysfunction and treatments.

BACKGROUND: Sacroiliac joints are affected by mechanical environments; the joints are formed under mechanical stimulation, receive impact of walking between the upper and lower parts of the bodies and can be a cause of pain due to non-physiological loads. However, there are so far very few studies that reviewed biomechanics of physiological and pathological sacroiliac joints. This review article aims to describe the current sacroiliac joint biomechanics. METHODS: Previous original papers have been summarized based on three categories: articular surface structure, sacroiliac joint motion and sacroiliac joint dysfunction and treatments. FINDINGS: Although the articular surface morphologies vary greatly from individual to individual, many researchers have tried to classify the joints into several types. It has been suggested that the surface morphologies may not change regardless of joint dysfunction, however, the relationship between the joint structure and pain are still unclear. The range of sacroiliac joint motion is demonstrated to be less than 1 mm and there is no difference between physiological and pathological joints. The sacroiliac joint absorbs shock within the pelvis by the joint structures of pelvic morphology, ligaments and fat tissues. The morphology and motion of the sacroiliac joints may be optimized for upright bipedal walking. INTERPRETATION: There is no doubt that pelvic mechanical environments affect pain induction and treatment; however, no one has yet provided a concrete explanation. Future research could help develop treatments based on sacroiliac joint biomechanics to support joint function.

The prevalence of sarcopenia in spondyloarthritis patients: a meta-analysis.

BACKGROUND: Spondyloarthritis (SpA) is a chronic inflammatory disorder that affects sacroiliac joints and spine, resulting in substantial disability. Sarcopenia, characterized by the loss of muscle mass and function, is a prevalent comorbidity in various chronic diseases. However, the exact prevalence of sarcopenia in SpA patients remains uncertain. The objective of this study is to conduct a systematic review and meta-analysis of the available literature to determine the prevalence of sarcopenia in SpA. METHODS: A comprehensive search was conducted in EMBASE, MEDLINE, WEB OF SCIENCE, and COCHRANE databases to identify relevant studies published up to 2023. Studies investigating the prevalence of sarcopenia in SpA patients were included. Data on study characteristics, participant demographics, diagnostic criteria for sarcopenia, and prevalence rates were extracted. Meta-analysis was performed using a random-effects model to estimate the overall prevalence of sarcopenia in SpA patients. RESULTS: A total of 16 studies that met the inclusion criteria were included in the systematic review. These studies encompassed a combined sample size of 999 patients with SpA. The meta-analysis findings revealed that the overall prevalence of sarcopenia in SpA patients was 25.0% (95% confidence interval: 0.127 to 0.352). Furthermore, the prevalence of presarcopenia and severe sarcopenia was found to be 21.0% and 8.7%, respectively. Subgroup analysis was conducted to examine different diagnostic criteria, subtypes, and sex of SpA in relation to sarcopenia. CONCLUSION: This systematic review and meta-analysis provide a comprehensive overview of the prevalence of sarcopenia in SpA patients. The findings suggest a high prevalence of sarcopenia in SpA patients, emphasizing the need for targeted interventions to prevent and manage sarcopenia. And further research is needed to explore the underlying mechanisms and potential therapeutic strategies for sarcopenia in SpA.

Learning imaging in axial spondyloarthritis: more than just a matter of experience.

OBJECTIVE: Reliable interpretation of imaging findings is essential for the diagnosis of axial spondyloarthritis (axSpA) and requires a high level of experience. We investigated experience-dependent differences in diagnostic accuracies using X-ray (XR), MRI and CT. METHODS: This post hoc analysis included 163 subjects with low back pain. Eighty-nine patients had axSpA, and 74 patients had other conditions (mechanical, degenerative or non-specific low back pain). Final diagnoses were established by an experienced rheumatologist before the reading sessions. Nine blinded readers (divided into three groups with different levels of experience) scored the XR, CT and MRI of the sacroiliac joints for the presence versus absence of axSpA. Parameters for diagnostic performance were calculated using contingency tables. Differences in diagnostic performance between the reader groups were assessed using the McNemar test. Inter-rater reliability was assessed using Fleiss kappa. RESULTS: Diagnostic performance was highest for the most experienced reader group, except for XR. In the inexperienced and semi-experienced group, diagnostic performance was highest for CT&MRI (78.5% and 85.3%, respectively). In the experienced group, MRI showed the highest performance (85.9%). The greatest difference in diagnostic performance was found for MRI between the inexperienced and experienced group (76.1% vs 85.9%, p=0.001). Inter-rater agreement was best for CT in the experienced group with κ=0.87. CONCLUSION: Differences exist in the learnability of the imaging modalities for axSpA diagnosis. MRI requires more experience, while CT is more suitable for inexperienced radiologists. However, diagnosis relies on both clinical and imaging information.

The Sacroiliac Joint: A Current State-of-the-Art Review.

¼ The sacroiliac joint (SIJ) is a common cause of low back pain and should be included in the differential diagnosis.¼ Nonoperative treatment of sacroiliac pain is always the first line of therapy; however, when it is unsuccessful and becomes chronic, then recurrent nonoperative treatment becomes expensive.¼ Surgical treatment is cost-effective in appropriately selected patients. High-quality clinical trials have demonstrated statistically and clinically significant improvement compared with nonsurgical management in appropriately selected patients.¼ Spinal fusion to the sacrum increases degeneration of the SIJ and frequency of SIJ pain.

Impact of Sacroiliac Interosseous Ligament Tension and Laxity on the Biomechanics of the Lumbar Spine: A Finite Element Study.

OBJECTIVE: To investigate the influence of sacroiliac interosseous ligament tension and laxity on the biomechanics of the lumbar spine. METHODS: A static analysis of a three-dimensional finite element model of the Lumbar-Pelvic is conducted to verify the model's effectiveness. Adjusting the sacroiliac ligament's elasticity modulus under a 10Nm lumbar flexion/extension moment, it simulates ligament tension/laxity to calculate vertebrae displacements, intervertebral disc stress and deformation, nucleus pulposus pressure, facet joint force, and ligament stress. RESULTS: With the elastic modulus of the sacroiliac ligament changing by +50%, -50%, and -90%, the angular displacement of vertebra 3 in forward flexion changes by +1.64%, -4.84%, and -42.3%, and the line displacements change by +5.7%, -16.4%, and -144.9%, respectively; and the angular displacements in backward extension change by +0.2%, -0.6%, -5.9% and the line displacements change by +5.5%, -14.3%, and -125.8%. However, the angular displacement and center distance between adjacent vertebrae do not change, leading to no change in the maximum stress of the intervertebral disc and the maximum pressure in the nucleus pulposus. Flexion and extension directly affect the deformation and stress magnitude and distribution in the lumbar spine. CONCLUSIONS: While sacroiliac interosseous ligament laxity and tension have little effect on disc deformation and stress, and nucleus pulposus pressure, they reduce the stability of the lumbar-sacral vertebrae. In a forward flexion state, the lumbar ligaments bear a large load and are prone to laxity, thereby increasing the risk of lumbar injury.

Validation of SPARCC MRI-RETIC e-tools for increasing scoring proficiency of MRI sacroiliac joint lesions in axial spondyloarthritis

BACKGROUND: The Spondyloarthritis Research Consortium of Canada (SPARCC) developers have created web-based calibration modules for the SPARCC MRI sacroiliac joint (SIJ) scoring methods. We aimed to test the impact of applying these e-modules on the feasibility and reliability of these methods. METHODS: The SPARCC-SIJ RETIC e-modules contain cases with baseline and follow-up scans and an online scoring interface. Visual real-time feedback regarding concordance/discordance of scoring with expert readers is provided by a colour-coding scheme. Reliability is assessed in real time by intraclass correlation coefficient (ICC), cases being scored until ICC targets are attained. Participating readers (n=17) from the EuroSpA Imaging project were randomised to one of two reader calibration strategies that each comprised three stages. Baseline and follow-up scans from 25 cases were scored after each stage was completed. Reliability was compared with a SPARCC developer, and the System Usability Scale (SUS) assessed feasibility. RESULTS: The reliability of readers for scoring bone marrow oedema was high after the first stage of calibration, and only minor improvement was noted following the use of the inflammation module. Greater enhancement of reader reliability was evident after the use of the structural module and was most consistently evident for the scoring of erosion (ICC status/change: stage 1 (0.42/0.20) to stage 3 (0.50/0.38)) and backfill (ICC status/change: stage 1 (0.51/0.19) to stage 3 (0.69/0.41)). The feasibility of both e-modules was evident by high SUS scores. CONCLUSION: The SPARCC-SIJ RETIC e-modules are feasible, effective knowledge transfer tools, and their use is recommended before using the SPARCC methods for clinical research and tria.

Use of MRI-based deep learning radiomics to diagnose sacroiliitis related to axial spondyloarthritis.

OBJECTIVES: This study aimed to evaluate the performance of a deep learning radiomics (DLR) model, which integrates multimodal MRI features and clinical information, in diagnosing sacroiliitis related to axial spondyloarthritis (axSpA). MATERIAL & METHODS: A total of 485 patients diagnosed with sacroiliitis related to axSpA (n = 288) or non-sacroiliitis (n = 197) by sacroiliac joint (SIJ) MRI between May 2018 and October 2022 were retrospectively included in this study. The patients were randomly divided into training (n = 388) and testing (n = 97) cohorts. Data were collected using three MRI scanners. We applied a convolutional neural network (CNN) called 3D U-Net for automated SIJ segmentation. Additionally, three CNNs (ResNet50, ResNet101, and DenseNet121) were used to diagnose axSpA-related sacroiliitis using a single modality. The prediction results of all the CNN models across different modalities were integrated using a stacking method based on different algorithms to construct ensemble models, and the optimal ensemble model was used as DLR signature. A combined model incorporating DLR signature with clinical factors was developed using multivariable logistic regression. The performance of the models was evaluated using receiver operating characteristic (ROC) curves, calibration curves, and decision curve analysis (DCA). RESULTS: Automated deep learning-based segmentation and manual delineation showed good correlation. ResNet50, as the optimal basic model, achieved an area under the curve (AUC) and accuracy of 0.839 and 0.804, respectively. The combined model yielded the highest performance in diagnosing axSpA-related sacroiliitis (AUC: 0.910; accuracy: 0.856) and outperformed the best ensemble model (AUC: 0.868; accuracy: 0.825) (all P < 0.05). Moreover, the DCA showed good clinical utility in the combined model. CONCLUSION: We developed a diagnostic model for axSpA-related sacroiliitis by combining the DLR signature with clinical factors, which resulted in excellent diagnostic performance.

EMERGENCY DEPARTMENT INTRAARTICULAR CORTICOSTEROID INJECTION FOR SACROILIAC JOINT DYSFUNCTION.

BACKGROUND: Sacroiliac joint (SIJ) dysfunction is a common but underrecognized source of low back pain (LBP). With provocative testing, emergency physicians can diagnose SIJ dysfunction and begin appropriate treatment in the emergency department (ED). DISCUSSION: For patients with significant pain from SIJ dysfunction, ultrasound-guided SIJ injection of anesthetic and corticosteroid can reduce patients' pain considerably. CONCLUSIONS: For patients who are good candidates for SIJ injection, emergency physicians can begin treatment in the ED, before the patient follows up with a specialist.

Interventional treatments for low back pain due to sacroiliac joint dysfunction: a systematic review of the literature.

PURPOSE: This systematic review aimed to report the current evidence in the literature about the efficacy of interventional treatments in the management of low back pain (LBP) due to sacroiliac joint dysfunction. METHODS: A systematic review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Medline, EMBASE, Scopus, CINAHL, Cochrane Library, and CENTRAL bibliographic databases were searched. The search was performed from October to December 2021, and articles from the inception of the database to December 2021 were searched. RESULTS: Fourteen studies were included for qualitative synthesis. Five studies used the traditional radiofrequency approach (tRF), five studies used cooled radiofrequency approach (cRF), one study used botulinum toxin (BT), two studies used steroid injection, triamcinolone (TA) and local anesthetics injections, and one study used pulsed radiofrequency (PRF) denervation. Two studies used sham as a comparator. CONCLUSIONS: Cooled radiofrequency seems to be the most effective treatment in improving pain and functionality, while intra-articular injections are helpful only as diagnostic tools. However, due to the lack of high-quality studies, it was not possible to draw significant conclusions.