Nociceptive Nerve Fibers in the Sacroiliac Joint in Humans:

Sacroiliac Joint: Function, Pathology, Treatment, and Contribution to Outcomes in Spine and Hip Surgery

➢ Low back pain has a lifetime incidence of up to 84% and represents the leading cause of disability in the United States; 10% to 38% of cases can be attributed to sacroiliac joint (SIJ) dysfunction as an important pain generator.➢ Physical examination of the SIJ, including >1 provocation test (due to their moderate sensitivity and specificity) and examination of adjacent joints (hip and lumbar spine) should be routinely performed in all patients presenting with low back, gluteal, and posterior hip pain.➢ Radiographic investigations including radiographs, computed tomography, and magnetic resonance imaging with protocols optimized for the visualization of the SIJs may facilitate the diagnosis of common pathologies.➢ Intra-articular injections with anesthetic can be helpful in localizing the source of low back pain. Over-the-counter analgesics, physiotherapy, intra-articular injections, radiofrequency ablation, and surgery are all management options and should be approached from the least invasive to the most invasive to minimize the risks of complications.➢ Lumbar fusion surgery predisposes patients to more rapid SIJ degeneration and can also result in more rapid degenerative changes in the hip joints, especially with SIJ fusion.➢ Hip surgery, including hip arthroplasty and preservation surgery, is not a risk factor for SIJ degeneration, although reduced outcomes following hip surgery can be seen in patients with degenerative SIJ changes.

Incidence of Sacroiliac Joint Pain Following Lumbar Fractures: A Retrospective-Cohort Study

BACKGROUND

Sacroiliac joint (SIJ) pain commonly affects patients with low back pain and can arise from traumatic and degenerative causes. However, the incidence of SIJ pain following lumbar fractures is not well understood.

METHODS

TriNetX, a national network of deidentified patient records, was retrospectively queried. The lumbar fracture cohort included 239,199 adults, while the no lumbar fracture group included 6,975,046 adults. Following a propensity-score match based on demographics and risk factors for SIJ, there were 239,197 patients in each cohort. The incidence of SIJ pain and clinical outcomes were analyzed from 1 day to 1 year following the index event. Moreover, the location and type of single-level lumbar fractures were reported. The incidence of SIJ pain for single-level fractures was compared using a χ2 goodness-of-fit.

RESULTS

The lumbar fracture cohort was more likely to develop SIJ pain at 3 months (odds ratio [OR]: 5.3, 95% confidence interval [CI]: 4.8-5.9), 6 months (OR: 4.4, 95% CI: 4.1-4.8), and 1 year (OR: 3.9, 95% CI: 3.6-4.2) postfracture. Among single-level lumbar fractures, the incidence of SIJ pain at 1 month (P = 0.005), 6 months (P = 0.010), and 1 year (P = 0.003) varied significantly, with the highest incidence in the L5 cohort.

CONCLUSIONS

Our findings suggest that lumbar fractures are a risk factor for developing SIJ pain. Moreover, the incidence of SIJ pain is greater following an L5 fracture than an L1 fracture. Further investigation is warranted to determine how the type and treatment of lumbar fractures affects the incidence of SIJ pain.

A New Approach to the Treatment of Sacroiliac Joint Pain and First Patient-Reported Outcomes Using a Novel Arthrodesis Technique for Sacroiliac Joint Fusion

Purpose

To report the development of a new sacroiliac joint (SIJ) arthrodesis system that can be used for isolated fusion of the SIJ and, unlike known implant systems, in combination with lumbar instrumentation or as an alternative to existing sacropelvic fixation (SPF) methods, and the patient-reported outcomes in two cases.

Materials and Methods

After a comprehensive review of 207 pelvic computed tomography (CT) datasets, an implant body was designed. Its shape was modeled based on the SIJ recess. A screw anchored in the ilium secures the position of the implant and allows connection to lumbar instrumentation. Two patients with confirmed SIJ syndrome underwent surgery with the anatomically adapted implant. They were evaluated preoperatively, 6 months, and 12 months postoperatively. Visual Analogue Scale (VAS), Oswestry Disability Index (ODI), Million Visual Analogue Scale (MVAS), Roland Morris Score (RMS), reduction of SIJ/leg pain, and work status were assessed. Bony fusion of the SIJ was evaluated by radiographs and CT 12 months after the procedure.

Results

Analysis of pelvic CT data revealed a wedge-shaped implant body in four different sizes. In the two patients, VAS decreased from 88 to 33 points, ODI improved from 67 to 35%, MVAS decreased from 80 to 36%, and RMS decreased from 18 to 9 points 12 months after surgery. SIJ pain reduction was 80% and 90%, respectively. Follow-up CT and radiographs showed solid bony integration.

Conclusion

The implant used takes into account the unique anatomy of the SIJ and also meets the requirements of a true arthrodesis. Initial results in two patients are promising. Biomechanical and clinical studies will have to show whether the considerable theoretical advantages of the new implant system over existing SIJ implants - in particular the possibility of connection to a lumbar stabilization system - and SPFs can be put into practice.

Heredity of pregnancy-related pelvic girdle pain in Sweden

INTRODUCTION

Pelvic girdle pain during and after pregnancy is a major public health problem with significant daily problems for affected women and their families. There is now accumulating evidence that pregnancy-related pelvic girdle pain originates from the sacroiliac joints and the pubic symphysis as well as their extra-articular ligaments. However, the heritability of the disease remains to be determined. We hypothesized that there is an increased familial risk of pregnancy-related pelvic girdle pain.

MATERIAL AND METHODS

A population-based national database linkage registry study of approximately 9.3 million individuals within 4.2 million families in Sweden with a recruitment period from 1997 to 2018. The Swedish Multi-generation register was used to find female pairs of twins, full siblings, half-siblings and first cousins where both in the pairs had a completed pregnancy. The outcome measure was diagnosis of pregnancy-related pelvic girdle pain (International Classification of Diseases-10 O26.7 [1997-2018]) in the first pregnancy. Data was obtained from the Swedish Hospital Discharge Register, the Swedish Outpatient Care Register, the Swedish Medical Birth Register, the Primary Healthcare Register, and Medical Treatment Register. Cox regression analysis was used to calculate adjusted estimated effect of the exposure variable familial history of pregnancy-related pelvic girdle pain on the outcome variable pregnancy-related pelvic girdle pain at first birth.

RESULTS

From the registers, 1 010 064 women pregnant with their first child within 795 654 families were collected. In total, 109 147 women were diagnosed with pregnancy-related pelvic girdle pain. The adjusted hazard ratio for a familial risk of pregnancy-related pelvic girdle pain was 2.09 (95% CI 1.85-2.37) among twins (monozygotic and dizygotic), 1.78 (95% CI 1.74-1.82) in full siblings, 1.16 (95% CI 1.06-1.28) in half-siblings from the mother, 1.09 (95% CI 1.024-1.16) in half-siblings from the father and 1.09 (95% CI 1.07-1.12) in first cousins.

CONCLUSIONS

This nationwide observational study showed a familial clustering of pregnancy-related pelvic girdle pain. The hazard ratio for the condition was associated with the degree of relatedness, suggesting that heredity factors contribute to the development of pregnancy-related pelvic girdle pain. There is no causal treatment available for pregnancy-related pelvic girdle pain and further studies are now encouraged to clarify the specific genetic factors that contribute to the disease and for future targeted interventions.

Sacroiliac Joint Degeneration and Pain After Spinal Arthrodesis: A Systematic Review

STUDY DESIGN

This was a systematic review.

OBJECTIVE

The present study aims to review the available literature concerning sacroiliac joint (SIJ) pain and degeneration after lumbosacral fixation to identify the prevalence and potential risk factors.

SUMMARY OF BACKGROUND DATA

Although numerous factors can predispose patients to SIJ degeneration and pain various clinical studies indicate lumbosacral arthrodesis as a major cause.

MATERIALS AND METHODS

The PubMed-MEDLINE, Cochrane Central Registry of Controlled Trials, and Embase Biomedical database were searched. Peer-reviewed comparative studies, cohort studies, case series studies and case control studies, conducted either in a retrospective or prospective design, that registered data about SIJ pain and degeneration after lumbosacral fixation were included.

RESULTS

Twenty-one studies including 2678 patients met the inclusion criteria. The percentage of SIJ pain after lumbosacral fixation diagnosed with injections and physical examination varied widely, from 3% to 90%. Among patients who underwent spinal fusion, SIJ pain prevalence was higher when arthrodesis was fixed compared with floating fusions (59% vs. 10%, P -value >0.05). The prevalence of SIJ degenerative changes at computed tomography scan was more frequent in patients who underwent spinal arthrodesis than in those who did not (75% vs. 38.2%, P -value ≤0.05).

CONCLUSION

According to current evidence, patients who received lumbosacral fixation are at risk of SIJ pain. Number of fused levels, involvement of pelvis or sacrum in the arthrodesis area, inadequate lumbosacral sagittal alignment, and site of bone graft harvesting could be possible risk factor leading to sacroiliac degeneration and pain after lumbar spine fixation that should be investigated by physicians. However, there is a lack of homogeneity of the studies that address the problem, therefore, further prospective comparative studies, with a homogeneous architecture and cohorts are needed.

LEVEL OF EVIDENCE

Level III.

Thermal versus cooled radiofrequency in patients with sacroiliac joint pain: a systematic review of the literature and pooled analysis of clinical outcomes

INTRODUCTION

Chronic low back pain (LBP) can be caused by sacroiliac joint (SIJ) disease. Many conditions could cause SIJ dysfunction. The lateral branches of the L4-S3 dorsal rami are responsible for the primary innervation of the posterior SI joint. Radiofrequency (RF) denervation represent an emerging promising treatment for refractory sacroiliac joint pain. There are different types of RF denervation such as thermal or cooled. Use of irrigation cooled electrodes allows targeted tissues to reach the neuroablative temperatures slowly, preventing collateral damage of adjacent tissue.

EVIDENCE ACQUISITION

We conducted electronic database (PubMed, Medline, Cochrane and Google Scholar) research (time frame: January 1st, 2010 to May 31st, 2021) for clinical studies that had tested conventional radiofrequency (RFT) and cooled radiofrequency (RFC) to treat sacroiliac joint pain. These studies were evaluated according to Level of Evidence. Quantitative assessment of qualifying studies was done using the random effects model. We calculated the pooled size effect using standardized mean difference (SMD) as the main effect measure.

EVIDENCE SYNTHESIS

We identified nine studies, with a total of 276 patients affected by sacroiliac joint pain and treated with radiofrequency. The analysis revealed a small and non-significant difference in pain reduction and an improvement in quality of life in RFT subgroup (Pain measured in Visual Analogic Scale: RFT subgroups SMD=-3.643 (95% CI -4.478, -2.807), RFC subgroup SMD=-3.285 (95% CI -4.428, -2.141), P=0.587; Quality of Life measured in Oswestry Disability Index: RFT subgroup SMD=-35.969 (95% CI -53.993%, -17.945%), RFC subgroup SMD=-20.589% (95% CI -33.424%. -7.754%), P=0.123). Publication bias was found in quality-of-life assessment due to the low number and high heterogeneity of studies. Two techniques showed no major complications.

CONCLUSIONS

Current evidence indicates no statistical difference between two techniques examined. The literature is currently lacking, and well-constructed randomized clinical trials are necessary to evaluate this deficient aspect.

Review of Opioid Sparing Interventional Pain Management Options and Techniques for Radiofrequency Ablations for Sacroiliac Joint Pain

PURPOSE OF REVIEW

The goal of this clinical review was to provide an update about the existing treatment options and associated evidence for various radiofrequency ablation techniques for sacroiliac joint pain. An electronic literature search on radiofrequency for the treatment of sacroiliac joint pain was conducted using PubMed, NCBI and Google Scholar. The following search keywords were used: radiofrequency ablation (cooled, pulsed, conventional, bipolar, intra-articular), sacroiliac joint and sacroiliac pain. The search was limited to human subjects, English language and articles with available full text. The bibliographic sections of all manuscripts were further searched for additional relevant citations. The full text of the relevant articles was reviewed by all the authors.

RECENT FINDINGS

Our study showed that radiofrequency ablation is a safe and effective treatment option that can be utilized to manage sacroiliac joint pain. It offers accessibility to the primary care physician, reduces office visits with "pain" as the primary complaint and provides the added benefit of acting as a non-opioid sparing means of analgesia.

Ultrasound-guided lateral branch radiofrequency ablation for sacroiliac joint pain

Sacroiliac joint (SIJ) pain is one of the leading causes of mechanical low back pain. Treatment includes conservative methods, surgery, and radiofrequency thermocoagulation (RFTC) as a novel therapeutic approach. Herein, we present a 71-year-old female patient who was first admitted to the outpatient clinic about four years ago. The medical history and physical examination findings were compatible with SIJ pain. After unresponsiveness to previous treatments, the patient successfully underwent ultrasound-guided RFTC using the lateral crest technique. This case report demonstrates, for the first time, the long-term efficacy of ultrasound-guided RFTC using the lateral crest technique in the management of SIJ pain.

Osteopathic approach to sacroiliac joint pain in pregnant patients

This paper aims to provide a comprehensive review of the management of sacroiliac (SI) joint pain in pregnant patients. Although SI joint pain is highly prevalent among pregnant patients, the unique anatomy of the joint is rarely discussed in a clinical setting. This paper provides comprehensive review of the epidemiology, anatomy, alarm findings, standard treatment, osteopathic assessment, and osteopathic manipulative treatment (OMT) of the SI joint, and it provides a general and in-depth understanding of the SI joint pain in pregnant patients and its management.

The effect of minimally invasive sacroiliac joint fusion compared with sham operation: study protocol of a prospective double-blinded multicenter randomized controlled trial

Background and purpose - The sacroiliac joint is increasingly recognized as a cause of pain in 15-30% of patients with low back pain. Nonoperative management is not always successful and surgical treatment with fusion of the joint is increasingly recommended. According to the literature, minimally invasive fusion reduces pain and improves function compared with nonoperative treatment. It is, however, unclear to what extent the placebo effect influences these results. Patients and methods - The trial is designed as a prospective multi-center, double-blind, randomized shamsurgery controlled trial with 2 parallel groups. 60 patients with a suspected diagnosis of sacroiliac joint pain confirmed with sacroiliac joint injection are included according to the trial inclusion criteria. Patients are randomized with a 1:1 allocation into 2 groups of 30 patients each. The primary end-point is group difference in sacroiliac joint pain intensity on the operated side at 6 months postoperatively, measured by the Numeric Rating Scale. The main objective is to examine whether there is a difference in pain reduction between patients treated with a minimally invasive fusion of the sacroiliac joint compared with patients undergoing a sham operation. Results - Unblinding occurs after the completed 6-month follow-up. The primary analysis will be performed when all patients have completed 6 months' follow-up. Follow-ups are continued to at least 2 years postoperatively. Data from the different groups will be compared based on the "intention to treat" principle.

Sacroiliac Joint Anatomy

The sacroiliac joint can be a source of low back pain. This review article summarizes current anatomic evidence of the innervation of the intraarticular and extraarticular parts of the sacroiliac joint relative to bony landmarks identifiable with fluoroscopy and ultrasound. This article aims to provide clinicians with an anatomic basis for clinical application to diagnostic blocks and radiofrequency ablation for sacroiliac pain to optimize clinical outcomes.

Ligaments stabilizing the sacrum and sacroiliac joint: a comprehensive review

The sacroiliac joint is a diarthrodial synovial joint in the pelvis. Anatomically, it is described as a symphysis, its synovial joint characteristics being limited to the distal cartilaginous portion on the iliac side. It is a continuous ligamentous stocking comprising interconnecting ligamentous structures and surrounding fascia. Its ligaments, the primary source of its stability, include the anterior, interosseous and dorsal sacroiliac, the iliolumbar, sacrotuberous, and sacrospinous. Structural reinforcement is also provided by neighboring fascia and muscles. Lower back pain is a common presentation of sacroiliac joint disease, the best-established treatments being corticosteroid injections, bipolar radiofrequency ablation, and sacroiliac joint fusion.

Image-guided spinal injection for pain management

Radiculopathy and spinal pain are debilitating conditions affecting millions of people worldwide each year. While most cases can be managed conservatively with physiotherapy and nonsteroidal anti-inflammatory medications, minimally invasive corticosteroid injections are the mainstay intervention for those not responsive to conservative treatment. Historically, spinal injections were performed in the absence of imaging guidance; however, imaging modalities, in particular fluoroscopy and computer tomography (CT), have become the standard of care in performing most of these procedures. Under imaging guidance, operators can accurately confirm needle placement and safely target localised pathologies.

Quantitative evaluation of the sacroiliac joint fixation in stress reduction on both sacroiliac joint cartilage and ligaments: A finite element analysis

BACKGROUND

The sacroiliac joint fixation is the last resort for patients with prolonged and severe joint pain. Although the clinical results of anterior fixations are conclusive, there exist several inevitable drawbacks with the surgical method such as the difficulty performing the surgery due to the presence of many organs. The posterior fixation technique has thus been developed to overcome those inconveniences. This study aims to assess in silico the mechanical environment following posterior and anterior fixations, focusing on stresses in both the sacroiliac cartilage and dorsal ligamentous part, as well as loads experienced by the pelvic ligaments.

METHODS

Sacroiliac joint cartilage, dorsal ligamentous part stresses and pelvic ligaments loads were evaluated with three types of fixation models. A vertical load of 600 N was applied, equally distributed via both acetabula when standing and sitting.

FINDINGS

Results show that the anterior sacroiliac joint fixation reduced von Mises stresses in the cartilage and dorsal ligamentous part and decreased ligaments loads more extensively than the posterior fixation when compared to the untreated model as a reference. However, the posterior fixation still remains the desirable and preferential treatment.

INTERPRETATION

The anterior sacroiliac joint fixation showed better performances compared to the posterior one; however, the lower invasive aspect of the latter is a fundamental clinical advantage which also has the possibility to be improved by considering various screws and cages configurations. This study provides a beneficial suggestion to improve the current fixation technique.

The Pelvic Girdle Pain deadlock: 2. Topics that, so far, have remained out of focus

INTRODUCTION

In our preceding paper, we concluded that Pelvic Girdle Pain (PGP) should be taken seriously. Still, we do not know its causes. Literature reviews on treatment fail to reveal a consistent pattern, and there are patients who do not respond well to treatment. We designated the lack of progress in research and in the clinic as 'deadlock', and proposed a 'deconstruction' of PGP, that is to say, taking PGP apart into its relevant dimensions.

PURPOSE

We examine the proposition that PGP may emerge as local inflammation. Inflammation would be a new dimension to be taken into account, between biomechanics and psychology. To explore the consequences of this idea, we present four different topics that, so far, have remained out of focus. One: The importance of microtrauma. Two: Ways to counteract chronification. Three: The importance of sickness behaviour when systemic inflammation turns into neuroinflammation of the brain. And Four: The mainly emotional and cognitive nature of chronic pain, and how aberrant neuroinflammation may render chronic pain intractable. For intractable pain, sleep and stress management are promising treatment options.

IMPLICATIONS

The authors hope that the present paper helps to stimulate the flexible creativity that is required to deal with the biological and psychological impact of PGP. Measuring inflammatory mediators in PGP should be a research priority. It should be understood that the boundaries between biology and psychology are becoming blurred. Clinicians must frequently monitor pain, disability, and mood, and be ready to switch treatment whenever the patient does not improve.

Understanding and managing pelvic girdle pain from a person-centred biopsychosocial perspective

INTRODUCTION

Clinicians need support to effectively implement a biopsychosocial approach to people with pelvic girdle pain disorders.

PURPOSE

A practical clinical framework aligned with a contemporary biopsychosocial approach is provided to help guide clinician's management of pelvic girdle pain. This approach is consistent with current pain science which helps to explain potential mechanistic links with co/multi-morbid conditions related to pelvic girdle pain. Further, this approach also aligns with the Common-Sense Model of Illness and provides insight into how an individual's illness perceptions can influence their emotional and behavioural response to their pain disorder. Communication is critical to supporting recovery and facilitating behaviour change within the biopsychosocial context and in this context, the patient interview is central to exploring the multidimensional nature of a persons' presentation. Focusing the biopsychosocial framework on targeted cognitive-functional therapy as a key component of care can help an individual with pelvic girdle pain make sense of their pain, build confidence and self-efficacy and facilitate positive behaviour and lifestyle change. There is growing evidence of the efficacy for this broader integrative approach, although large scale effectiveness trials are still needed. An in-depth case study provides guidance for clinicians, showing 'how to' implement these concepts into their own practice within a coherent practical framework.

IMPLICATIONS

This framework can give clinicians more confidence in understanding and managing pelvic girdle pain. The framework provides practical strategies to assist clinicians with implementation; assisting the transition from knowing to doing in an evidence-informed manner that resonates with real world practice.

The Safety Profile of Percutaneous Minimally Invasive Sacroiliac Joint Fusion

STUDY DESIGN

Literature review.

OBJECTIVES

Systematic review of the existing literature to determine the safety of minimally invasive (MI) sacroiliac (SI) joint fusion through the determination of the rate of procedural and device-related intraoperative and postoperative complications.

METHODS

All original studies with reported complication rates were included for analysis. Complications were defined as procedural if secondary to the MI surgery and device related if caused by placement of the implant. Complication rates are reported using descriptive statistics. Random-effects meta-analysis was performed for preoperative and postoperative Visual Analog Score (VAS) pain ratings and Oswestry Disability Index (ODI) scores.

RESULTS

Fourteen studies of 720 patients (499 females/221 males) with a mean follow-up of 22 months were included. Ninety-nine patients (13.75%) underwent bilateral SI joint arthrodesis resulting in a total of 819 SI joints fused. There were 91 reported procedural-related complications (11.11%) with the most common adverse event being surgical wound infection/drainage (n = 17). Twenty-five adverse events were attributed to be secondary to placement of the implant (3.05%) with nerve root impingement (n = 13) being the most common. The revision rate was 2.56%. MI SI joint fusion reduced VAS scores from 82.42 (95% confidence interval [CI] 79.34-85.51) to 29.03 (95% CI 25.05-33.01) and ODI scores from 57.44 (95% CI 54.73-60.14) to 29.42 (95% CI 20.62-38.21).

CONCLUSIONS

MI SI joint fusion is a relatively safe procedure but is not without certain risks. Further work must be done to optimize the procedure's complication profile. Possible areas of improvement include preoperative patient optimization, operative technique, and use of intraoperative real-time imaging.

Changing the Narrative in Diagnosis and Management of Pain in the Sacroiliac Joint Area

The sacroiliac joint (SIJ) is often considered to be involved when people present for care with low back pain where SIJ is located. However, determining why the pain has arisen can be challenging, especially in the absence of a specific cause such as pregnancy, disease, or trauma, when the SIJ might be identified as a source of symptoms with the help of manual clinical tests. Nonspecific SIJ-related pain is commonly suggested to be causally associated with movement problems in the SIJ(s)-a diagnosis traditionally derived from manual assessment of movements of the SIJ complex. Management choices often consist of patient education, manual treatment, and exercise. Although some elements of management are consistent with guidelines, this Perspective article argues that the assumptions on which these diagnoses and treatments are based are problematic, particularly if they reinforce unhelpful, pathoanatomical beliefs. This article reviews the evidence regarding the clinical detection and diagnosis of SIJ movement dysfunction. In particular, it questions the continued use of assessing movement dysfunction despite mounting evidence undermining the biological plausibility and subsequent treatment paradigms based on such diagnoses. Clinicians are encouraged to align their assessment methods and explanatory models with contemporary science to reduce the risk of their diagnoses and choice of intervention negatively affecting clinical outcomes.

Building a Collaborative Model of Sacroiliac Joint Dysfunction and Pelvic Girdle Pain to Understand the Diverse Perspectives of Experts

BACKGROUND

Pelvic girdle pain (PGP) and sacroiliac joint (SIJ) dysfunction/pain are considered frequent contributors to low back pain (LBP). Like other persistent pain conditions, PGP is increasingly recognized as a multifactorial problem involving biological, psychological, and social factors. Perspectives differ between experts and a diversity of treatments (with variable degrees of evidence) have been utilized.

OBJECTIVE

To develop a collaborative model of PGP that represents the collective view of a group of experts. Specific goals were to analyze structure and composition of conceptual models contributed by participants, to aggregate them into a metamodel, to analyze the metamodel's composition, and to consider predicted efficacy of treatments.

DESIGN

To develop a collaborative model of PGP, models were generated by invited individuals to represent their understanding of PGP using fuzzy cognitive mapping (FCM). FCMs involved proposal of components related to causes, outcomes, and treatments for pain, disability, and quality of life, and their connections. Components were classified into thematic categories. Weighting of connections was summed for components to judge their relative importance. FCMs were aggregated into a metamodel for analysis of the collective opinion it represented and to evaluate expected efficacy of treatments.

RESULTS

From 21 potential contributors, 14 (67%) agreed to participate (representing six disciplines and seven countries). Participants' models included a mean (SD) of 22 (5) components each. FCMs were refined to combine similar terms, leaving 89 components in 10 categories. Biomechanical factors were the most important in individual FCMs. The collective opinion from the metamodel predicted greatest efficacy for injection, exercise therapy, and surgery for pain relief.

CONCLUSIONS

The collaborative model of PGP showed a bias toward biomechanical factors. Most efficacious treatments predicted by the model have modest to no evidence from clinical trials, suggesting a mismatch between opinion and evidence. The model enables integration and communication of the collection of opinions on PGP.

Fluoroscopically Guided vs Landmark-Guided Sacroiliac Joint Injections: A Randomized Controlled Study

OBJECTIVES

To determine the prevalence of intra- and extra-articular sacroiliac joint (SIJ) pain, which injection is more beneficial, and whether fluoroscopy improves outcomes.

PATIENTS AND METHODS

This patient- and evaluator-blinded comparative effectiveness study randomized 125 participants with SIJ pain from April 30, 2014, through December 12, 2017, to receive fluoroscopically guided injections into the joint capsule (group 1) or "blind" injections to the point of maximum tenderness using sham radiographs (group 2). The primary outcome was average pain on a 0 to 10 scale 1 month after injection. A positive outcome was defined as at least a 2-point decrease in average pain score coupled with positive (>3) satisfaction on a Likert scale from 1 to 5.

RESULTS

For the primary outcome, no significant differences were observed between groups (mean ± SD change from baseline, -2.3±2.4 points in group 1 vs -1.7±2.3 points in group 2; 95% CI, -0.33 to 1.36 points for adjusted difference; P=.23), nor was there a difference in the proportions of positive blocks (61% vs 62%) or 1-month categorical outcome (48% vs 40% in groups 1 and 2, respectively; P=.33). At 3 months, the mean ± SD reductions in average pain (-1.8±2.1 vs -0.9 ± 2.0 points; 95% CI, 0.11 to 1.58 points for adjusted difference; P=.02) and worst pain (-2.2±2.5 vs -1.4±2.0 points; 95% CI, 0.01 to 1.66 points for adjusted difference; P=.049) were greater in group 1 than 2, with other outcome differences falling shy of statistical significance.

CONCLUSION

Although fluoroscopically guided injections provide greater intermediate-term benefit in some patients, these differences are modest and accompanied by large cost differences.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT02096653.

The Association of Variations in Hip and Pelvic Geometry With Pregnancy-Related Sacroiliac Joint Pain Based on a Longitudinal Analysis

STUDY DESIGN

Cross-sectional study using radiological measurements and longitudinal data analysis.

OBJECTIVE

We aim to explore hip/pelvic geometry on anteroposterior radiographs and examine if such parameters are associated with clinical symptoms.

SUMMARY OF BACKGROUND DATA

Pregnancy-related sacroiliac joint pain is a common disease and is responsible to the disability of daily activities. The etiology is likely to be correlated with the biomechanical factors which are determined by trunk load and hip/pelvic geometry. Previous studies have already found the association between symptoms and weight increase during pregnancy. However, the relationship between bony anatomy and pregnancy-related sacroiliac joint pain remains unknown.

METHODS

In total, 72 women were included in the final analysis. In pregnant women with self-reported sacroiliac joint pain, pain scores at 12, 24, 30, and 36 weeks of pregnancy were recorded and included in a mixed-effect linear regression model as dependent variables. The radiological measurements were included as independent variables. Furthermore, to investigate the relationship between hip/pelvic geometry and the activity-specific nociceptive phenomenon, the radiological measurements between patients with and without activity-induced pain were compared using a binominal logistic regression model.

RESULTS

The relative bilateral is chial tuberosity distance (betta coefficient: 0.078; P = 0.015) and the relative bilateral femoral head length (betta coefficient: 0.011; P = 0.028) showed significant interactions with the slope of pain scores. Moreover, women whose pain exacerbate during prolonged walking had a higher odds in hip/pelvic geometry of the bilateral ischial tuberosity distance (odds ratio [OR]: 1.12; P = 0.050) and the bilateral femoral head length (OR: 1.16; P = 0.076) with approximately significant P-value.

CONCLUSION

These data indicate hip/pelvic anatomical variations are associated with the degree of pain increasing and the activity-specific pain during pregnancy, which may help to have further understanding on the biomechanical factor in developing pregnancy-related sacroiliac joint pain.

LEVEL OF EVIDENCE

3.

CGRP and Painful Pathologies Other than Headache

CGRP has long been suspected as a mediator of arthritis pain, although evidence that CGRP directly mediates human musculoskeletal pain remains circumstantial. This chapter describes in depth the evidence surrounding CGRP's association with pain in musculoskeletal disorders and also summarises evidence for CGRP being a direct cause of pain in other conditions. CGRP-immunoreactive nerves are present in musculoskeletal tissues, and CGRP expression is altered in musculoskeletal pain. CGRP modulates musculoskeletal pain through actions both in the periphery and central nervous system. Human observational studies, research on animal arthritis models and the few reported randomised controlled trials in humans of treatments that target CGRP provide the context of CGRP as a possible pain biomarker or mediator in conditions other than migraine.

A Randomized Controlled Trial of Fluoroscopically-Guided Sacroiliac Joint Injections: A Comparison of the Posteroanterior and Classical Oblique Techniques

OBJECTIVE

The sacroiliac joint can be a primary source of pain or part of multifactorial syndromes. As there is no single historical, physical examination-based, or radiological feature that definitively establishes a diagnosis of sacroiliac joint pain, diagnostic blocks are regarded as the gold standard. The primary aim of this randomized trial was to compare the posteroanterior approach with the classic oblique approach for sacroiliac joint injection based on an assessment of procedure times and patient-reported pain outcomes in subjects scheduled for fluoroscopically-guided sacroiliac joint injections.

METHODS

Thirty patients were randomized into 2 groups of 15 patients each. The endpoints measured included the total length of procedure time, fluoroscopic time, needling time (length of time the needle was maneuvered), and pre- and postprocedure visual analogue scale pain scores.

RESULTS

The posteroanterior approach was significantly shorter in terms of procedure time (p=0.03) and needling time (p=0.01) than the oblique approach. Adjusting for body mass index, the mean procedure and needling times were significantly shorter in the posteroanterior group than in the oblique group.

CONCLUSION

This study of the posteroanterior approach for fluoroscopic-guided sacroiliac joint injection observed shorter times for fluoroscopy, needling, and the overall procedure than were recorded for the widely prevalent oblique approach. This may translate to lower radiation exposure, lower procedural costs, and enhanced ergonomics of fluoroscopicallyguided sacroiliac joint injections.

Widespread pain in axial spondyloarthritis: clinical importance and gender differences

Background

There is a remarkable lack of detailed knowledge on pain areas in axial spondyloarthritis (axSpA), and their clinical relevance is largely unknown. Pain area may reflect local disease processes, but amplification of nervous system signalling may alter this relationship. Also, gender differences in pain area may exist in axSpA, possibly confounding disease activity outcomes. Therefore, we firstly detailed pain locations in axSpA and evaluated gender differences. Secondly, we explored the relationship of regional pain definitions with clinical outcomes. Finally, we explored the role of pain area in the assessment of disease activity.

Methods

Body charts informed on the presence of axial, peripheral articular and non-articular pain in 170 patients (108 men, 62 women) with axSpA. Multivariate Odds Ratios (ORs) were used to compare genders. General linear models were used to explore clinical differences in disease activity (Bath Ankylosing Spondylitis Disease Activity Index [BASDAI]), activity limitations (Bath Ankylosing Spondylitis Functional Index [BASFI]), fear of movement (Tampa Scale for Kinesiophobia 11-item version [TSK-11]), anxiety (Hospital Anxiety and Depression Scale subscale anxiety [HADS-A]) and depression (HADS subscale depression [HADS-D]) between four subgroups classified by widespread non-articular pain (WNAP+/−) and physician global assessment of disease activity (PGDA+/−) (p < .05). Principal Component Analysis (PCA) was performed to explore gender differences in the structure of disease activity.

Results

Axial thoracic pain was least prevalent (lumbar, 74.4%; cervical, 47.6%; cervicothoracic, 47.6%; thoracic, 32.4%), but it was about three times more likely in women (OR, 2.92; p = .009). Axial cervicothoracic junction pain spread more diffusely in women (OR, 2.48; p = .018). Women exhibited a two- to threefold increased likelihood of widespread axial (OR, 3.33; p = .007) and peripheral articular (OR, 2.34; p = .023) pain. A subgroup of WNAP+/PGDA− combined with low PGDA (27% of all patients) was associated with worse BASFI, BASDAI, HADS-A and HADS-D in men and worse TSK-11 and HADS-A in women (p < .05). Disease activity outcomes showed a two-factor structure in women but not in men.

Conclusions

In patients with axSpA, the location and spread of pain was different between genders and was related to worse clinical status. On the basis of pain area and PGDA, clinical subgroups exhibiting a remarkably distinct health status were identified. Outcome instruments such as BASDAI should acknowledge gender differences to ensure structural validity.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1626-8) contains supplementary material, which is available to authorized users.

A Diagnostic Scoring System for Sacroiliac Joint Pain Originating from the Posterior Ligament

Objective

Sacroiliac joint (SIJ) pain originating from the posterior ligament manifests in not only the buttocks but also the groin and lower extremities and thus may be difficult to discern from pain secondary to other lumbar disorders. We aimed to develop a simple clinical diagnostic tool to help physicians distinguish between patients with SIJ pain originating from the posterior ligament and those with lumbar disc herniation (LDH) or lumbar spinal canal stenosis (LSS).

Design

Prospective case-control study.

Patients and Methods

We evaluated 62 patients with SIJ pain originating from the posterior ligament and 59 patients with LDH and LSS. Pain areas, pain increasing positions, provocation test, and tenderness points were investigated. A scoring system based on multivariate logistic regression equations using the investigated items was developed.

Results

Two pain areas (the posterosuperior iliac spine (PSIS) detected by the one-finger test and groin), pain while sitting on a chair, provocation test, and two tenderness points (PSIS and the sacrotuberous ligament) had high odds ratios (range, 25.87–1.40) and were used as factors in the scoring system. An integer score derived from the regression coefficient and clinical experience was assigned to each identified risk factor. The sum of the risk score for each patient ranged from 0–9. This scoring system had a sensitivity of 90.3% and a specificity of 86.4% for a positivity cutoff point of 4.

Conclusion

The scoring system can help distinguish between patients with SIJ pain originating from the posterior ligament and those with LDH and LSS.

Pain in ankylosing spondylitis: a neuro-immune collaboration

Clinicians have commonly differentiated chronic back pain into two broad subsets: namely, non-inflammatory (or mechanical) back pain and inflammatory back pain. As the terminology suggests, the latter category, in which ankylosing spondylitis (AS) is prominent, presupposes a close link between pain and inflammation. Advances in research into the genetics and immunology of AS have improved our understanding of the inflammatory processes involved in this disease, and have led to the development of potent anti-inflammatory biologic therapeutic agents. However, evidence from clinical trials and from biomarker and imaging studies in patients with AS indicate that pain and inflammation are not always correlated. Thus, the assumption that pain in AS is a reliable surrogate marker for inflammation might be an over-simplification. This Review provides an overview of current concepts relating to neuro-immune interactions in AS and summarizes research that reveals an increasingly complex interplay between the activation of the immune system and pain pathways in the nervous system. The different types of pain experienced by patients with AS, insights from brain imaging studies, neurological mechanisms of pain, sex bias in pain and how the immune system can modify pain in patients with AS are also discussed.

Randomized Controlled Trial of Minimally Invasive Sacroiliac Joint Fusion Using Triangular Titanium Implants vs Nonsurgical Management for Sacroiliac Joint Dysfunction: 12-Month Outcomes

BACKGROUND

Sacroiliac joint (SIJ) dysfunction is a prevalent cause of chronic, unremitting lower back pain.

OBJECTIVE

To concurrently compare outcomes after surgical and nonsurgical treatment for chronic SIJ dysfunction.

METHODS

A total of 148 subjects with SIJ dysfunction were randomly assigned to minimally invasive SIJ fusion with triangular titanium implants (n = 102) or nonsurgical management (n = 46). Pain, disability, and quality-of-life scores were collected at baseline and at 1, 3, 6, and 12 months. Success rates were compared using Bayesian methods. Crossover from nonsurgical to surgical care was allowed after the 6-month study visit was complete.

RESULTS

Six-month success rates were higher in the surgical group (81.4% vs 26.1%; posterior probability of superiority > 0.9999). Clinically important (≥ 15 point) Oswestry Disability Index improvement at 6 months occurred in 73.3% of the SIJ fusion group vs 13.6% of the nonsurgical management group (P < .001). At 12 months, improvements in SIJ pain and Oswestry Disability Index were sustained in the surgical group. Subjects who crossed over had improvements in pain, disability, and quality of life similar to those in the original surgical group. Adverse events were slightly more common in the surgical group (1.3 vs 1.1 events per subject; P = .31).

CONCLUSION

This Level 1 study showed that minimally invasive SIJ fusion using triangular titanium implants was more effective than nonsurgical management at 1 year in relieving pain, improving function, and improving quality of life in patients with SIJ dysfunction caused by degenerative sacroiliitis or SIJ disruptions. Pain, disability, and quality of life also improved after crossover from nonsurgical to surgical treatment.

Pelvic Belt Effects on Health Outcomes and Functional Parameters of Patients with Sacroiliac Joint Pain

Introduction

The sacroiliac joint (SIJ) is a common source of low back pain. However, clinical and functional signs and symptoms correlating with SIJ pain are widely unknown. Pelvic belts are routinely applied to treat SIJ pain but without sound evidence of their pain-relieving effects. This case-control study compares clinical and functional data of SIJ patients and healthy control subjects and evaluates belt effects on SIJ pain.

Methods

17 SIJ patients and 17 healthy controls were included in this prospective study. The short-form 36 survey and the numerical rating scale were used to characterize health-related quality of life in patients in a six-week follow-up and the pain-reducing effects of pelvic belts. Electromyography data were obtained from the gluteus maximus, biceps femoris, rectus femoris and medial vastus. Alterations of muscle activity, variability and gait patterns were compared in patients and controls along with the belts’ effects in a dynamic setting when walking.

Results

Significant improvements were observed in the short-form 36 survey of the SIJ patients, especially in the physical health subscores. Minor declines were also observed in the numerical rating scale on pain. Belt-related changes of muscle activity and variability were similar in patients and controls with one exception: the rectus femoris activity decreased significantly in patients with belt application when walking. Further belt effects include improved cadence and gait velocity in patients and controls.

Conclusions

Pelvic belts improve health-related quality of life and are potentially attributed to decreased SIJ-related pain. Belt effects include decreased rectus femoris activity in patients and improved postural steadiness during locomotion. Pelvic belts may therefore be considered as a cost-effective and low-risk treatment of SIJ pain.

Trial Registration

ClinicalTrials.gov NCT02027038

Asymmetric pelvic bracing and altered kinematics in patients with posterior pelvic pain who present with postural muscle delay

BACKGROUND

The purpose of the study was to examine the muscle activity and hip-spine kinematics in a group of individuals diagnosed with posterior pelvic girdle pain and confirmed postural muscle delay during a repeated fast hip flexion task.

METHODS

Twenty-four (12 pain and 12 control) age and sex matched participants performed a repeated fast hip flexion task to auditory signal. Surface EMG activity in the external and internal oblique, the multifidus, the gluteus maximus and biceps femoris in the stance-limb was examined for onset timing and EMG integral. Sagittal plane hip (swing limb) and spine kinematics were examined for group and side differences over the repeated trials.

FINDINGS

While the pain group lacked significant feedforward muscle activity they displayed higher muscle activity at movement onset in the biceps femoris bilaterally (p<0.05) as well as the external oblique (p<0.05) during motion of the symptomatic side. Furthermore, the pain group experienced asymmetrical spinal range of motion with increased motion on the contralateral side (p<0.001) and reduced flexion velocity on the symptomatic side (p<0.001).

INTERPRETATION

The findings support previous hypotheses regarding the effect of increased biceps activity on pelvic control during lumbo-pelvic rotation. Further, there appears to be a symptom led strategy for bracing the innominate through opposing tension in the biceps and external oblique during movement of the painful side. Such asymmetrical pelvic girdle bracing may be a strategy to increase the stability of the pelvis in light of the failed load transfer mechanism. Putatively, this strategy may increase the mechanical stress on the sacroiliac joint exacerbating pain complaints.

Sacroiliac joint radiofrequency ablation with a multilesion probe: a case series of 60 patients

This retrospective case series of patients with refractory sacroiliac joint (SIJ) pain presents our first 77 SIJ radiofrequency ablation (RFA) procedures performed with a multilesion probe. Of these, 16 (20.8%) provided no relief; 55 (71.4%) provided >50% pain relief at 6 weeks; 42 (54.5%, 95% confidence interval, 42.8%-65.8%) provided >50% pain relief at 6 months; and 12 (15.6%) continued to provide >50% pain relief at 1 year. These results compare favorably to those published using other RFA techniques. In conclusion, more than half of our patients with refractory SIJ pain received some pain relief for at least 6 months after RFA.

Sacroiliac joint pain: a comprehensive review of epidemiology, diagnosis and treatment

Sacroiliac joint (SIJ) pain is an underappreciated source of mechanical low back pain, affecting between 15 and 30% of individuals with chronic, nonradicular pain. Predisposing factors for SIJ pain include true and apparent leg length discrepancy, older age, inflammatory arthritis, previous spine surgery, pregnancy and trauma. Compared with facet-mediated and discogenic low back pain, individuals with SIJ pain are more likely to report a specific inciting event, and experience unilateral pain below L5. Owing in part to its size and heterogeneity, the pain referral patterns of the SIJ are extremely variable. Although no single physical examination or historical feature can reliably identify a painful SIJ, studies suggest that a battery of three or more provocation tests can predict response to diagnostic blocks. Evidence supports both intra- and extra-articular causes for SIJ pain, with clinical studies demonstrating intermediate-term benefit for both intra- and extra-articular steroid injections. In those who fail to experience sustained relief from SIJ injections, radiofrequency denervation may provide significant relief lasting up to 1 year. This review covers all aspects of SIJ pain, with the treatment section being primarily focused on procedural interventions.

The sacroiliac joint: an overview of its anatomy, function and potential clinical implications

This article focuses on the (functional) anatomy and biomechanics of the pelvic girdle and specifically the sacroiliac joints (SIJs). The SIJs are essential for effective load transfer between the spine and legs. The sacrum, pelvis and spine, and the connections to the arms, legs and head, are functionally interrelated through muscular, fascial and ligamentous interconnections. A historical overview is presented on pelvic and especially SIJ research, followed by a general functional anatomical overview of the pelvis. In specific sections, the development and maturation of the SIJ is discussed, and a description of the bony anatomy and sexual morphism of the pelvis and SIJ is debated. The literature on the SIJ ligaments and innervation is discussed, followed by a section on the pathology of the SIJ. Pelvic movement studies are investigated and biomechanical models for SIJ stability analyzed, including examples of insufficient versus excessive sacroiliac force closure.

Experimental pelvic pain facilitates pain provocation tests and causes regional hyperalgesia

The extra-articular sacroiliac joint (SIJ) structure is a potential source for low back and pelvic pain. This study hypothesised that experimental pain induced in a superficial pelvic ligament causes (1) hyperalgesia to pressure, (2) distinct pain referral, and (3) an increased frequency of positive pain provocation tests of the SIJ complex. Thirty healthy subjects (15 females) participated in this study designed as a randomised crossover trial. Pain was induced in the long posterior sacroiliac ligament by injection of hypertonic saline, with the contralateral ligament injected with isotonic saline as control. Pain intensity was assessed on an electronic visual analogue scale (VAS). Pressure pain thresholds (PPTs) and pain provocation tests were assessed on 3 occasions: at baseline, after injection, and when pain had subsided. PPT sites were located bilaterally at the injection site, lateral to spinous processes of S2 and L5, and at the gluteus medius and gastrocnemius muscles. Hypertonic saline caused significantly higher VAS scores and more extended pain referral than isotonic saline (P<0.001). PPTs at the injection site and lateral to S2 were significantly reduced after hypertonic saline compared with baseline and isotonic saline (P<0.002). Significantly more subjects had positive pain provocation tests after hypertonic (67% of subjects) compared with isotonic saline (20%; P<0.001). These data demonstrate that the extra-articular SIJ structure accommodates nociceptors that are capable of inducing pain referral and regional hyperalgesia sensitive to manual pain provocation tests similar to what previously have been found in pelvic girdle pain patients.

A finite element analysis of sacroiliac joint ligaments in response to different loading conditions

STUDY DESIGN

A finite element analysis of the sacroiliac joint (SIJ) and its associated ligaments utilizing a three-dimensional model constructed from computed tomography scans.

OBJECTIVE

To characterize the sacroiliac ligament strains in response to flexion, extension, and axial rotation loads and quantify the changes in SIJ stress and angular displacement in response to changes in ligament stiffness.

SUMMARY OF BACKGROUND DATA

The SIJ may be a major contributor to low back pain in up to 13% to 30% of patients. States of ligament laxity are often associated with hypermobility and possibly pain of SIJ origin. The mechanism by which the SIJ generates pain is both controversial and poorly understood.

METHODS

A finite element model of the human pelvis, SIJs, and sacroiliac ligaments was constructed from computed tomography scans. Ligament stiffnesses were altered and the SIJ stresses were compared with the original case. For simulated flexion, extension, and axial rotation scenarios, sacroiliac ligament strains were characterized and compared.

RESULTS

Sacroiliac joint stress and angular motion increases as ligament stiffness decreases. Periarticular intraligamentous strains vary depending on the magnitude and direction of the applied loads. Maximum ligamentous strains occur at the interosseous sacroiliac ligament.

CONCLUSION

The sacroiliac ligaments function to constrain the SIJ and decrease stress across the SIJ for different load scenarios. Decreasing sacroiliac ligament stiffness leads to both increased joint motion and stress.