Anatomy and pathophysiology of the sacroiliac joint

Radiological Insights into Sacroiliitis: A Narrative Review

Sacroiliitis is the inflammation of the sacroiliac joint, the largest axial joint in the human body, contributing to 25% of lower back pain cases. It can be detected using various imaging techniques like radiography, MRI, and CT scans. Treatments range from conservative methods to invasive procedures. Recent advancements in artificial intelligence offer precise detection of this condition through imaging. Treatment options range from physical therapy and medications to invasive methods like joint injections and surgery. Future management looks promising with advanced imaging, regenerative medicine, and biologic therapies, especially for conditions like ankylosing spondylitis. We conducted a review on sacroiliitis using imaging data from sources like PubMed and Scopus. Only English studies focusing on sacroiliitis's radiological aspects were included. The findings were organized and presented narratively.

The Durability and Efficacy of Cryopreserved Human Umbilical Cord Tissue Allograft for the Supplementation of Cartilage Defects Associated with the Sacroiliac Joint: A Case Series

This Institutional Review Board (IRB)-approved retrospective observational protocol aims to report the safety and efficacy of birth tissue allografts applied in 38 patients with treatment-resistant sacroiliac (SI) joint pain. The research methodology consisted of an observational recording of the Numeric Pain Rating Scale (NPRS) and the Western Ontario and McMaster Universities Arthritis Index (WOMAC), which measure pain, stiffness, and physical function. No adverse events or adverse reactions were observed in the 38 patients. Statistically significant improvements in NPRS and WOMAC scores of the affected SI joint were reported after 90 days. The observational data suggests that Wharton’s jelly allograft applications are safe, minimally invasive, and efficacious. They may present an alternative to surgery for patients who fail conservative and procedural management of pain originating from chondral cartilage degeneration of the SI joint.

The association of parturition scars and pelvic shape: A geometric morphometric study

OBJECTIVES

Pelvic features, mostly known as parturition scars, have been extensively studied in the last decades and are frequently investigated in archaeological and forensic contexts. It is still unclear, however, whether they really relate to pregnancy and birth, or whether these features are caused by other biomechanical factors. Because the length and difficulty of labor correlates with the form of the birth canal, we studied the association between the expression of pelvic features and pelvic shape using geometric morphometrics.

MATERIALS AND METHODS

We scored the expression of the preauricular sulcus, margo auricularis groove, sacral preauricular extension, dorsal and ventral pubic pitting for 54 individuals from a 19th century collection and 19 individuals from the Bronze Age cemetery of Hainburg-Teichtal, Austria. Based on photogrammetric surface models, pelvic shape was captured by 331 landmarks and semilandmarks. The multivariate association between pelvic features and pelvic shape was explored by partial least squares analysis.

RESULTS

Within the female subsample, we detected a significant association of a constrained birth canal with a strong expression of the preauricular sulcus, the margo auricularis groove, and a retroverted position of the acetabulum. No significant association was found among males.

DISCUSSION

This suggests that difficult or prolonged labor may indeed cause more strongly expressed pelvic features, presumably because of increased strain of the pelvic ligaments during birth. Furthermore, the retroversion of the acetabulum, which is known to cause sacroiliac joint dysfunction, changes the strain on pelvic ligaments and can thus also result in the development of pronounced pelvic features.

Iatrogenic sacroiliac joint syndrome after percutaneous pedicle screw fixation at the L5-S1 level: case report

BACKGROUND AND IMPORTANCE

This article reports an unexpected complication of percutaneous pedicle screw fixation at the L5-S1 level.

CLINICAL PRESENTATION

We describe a 66-year-old man who underwent anterior lumbar interbody fusion followed by percutaneous pedicle screw fixation at the L5-S1 level. The Sextant pedicle screw system was used. The patient experienced postoperative sacroiliac joint syndrome caused by the screw head and rod tip. In the immediate postoperative period, the preoperative right-side leg pain improved, but the patient complained of left-side buttock and leg pain. The left-side screws were removed, and after revision surgery, the left-side pain disappeared. However, at that time, right-side pain recurred. We found that the screw head and rod had violated the iliac crest and the sacroiliac joint, causing referred pain rather than radicular pain. After the screw head was repositioned and the rod was replaced with a new shorter rod with a blunt end, the patient's symptom was relieved.

CONCLUSION

Surgeons should be aware of this unprecedented adverse effect when planning percutaneous pedicle screw fixation at the L5-S1 level. An android pelvis with a narrow and high iliac crest can be a risk factor. Careful preoperative evaluation and more accurate surgical technique are needed to prevent this type of complication.

The role of radiofrequency ablation for sacroiliac joint pain: a meta-analysis

Radiofrequency ablation (RFA) has become an option for those with chronic or refractory sacroiliac (SI) joint pain. The purpose of this critical review is to assess the existing literature and conduct a meta-analysis to assess the effectiveness of RFA of the SI joint for pain relief at 3 and 6 months' after an RFA procedure. An electronic search of PubMed, OVID, Medline, and CINAHL were conducted with keywords; sacroiliac joint, sacroiliac pain, sacroiliac syndrome, sacroiliac radiofrequency ablation, sacroiliac neurolysis, sacroiliac injection, and low back pain. Articles that addressed RFA of the SI joint were reviewed. Ten articles ranging from inception to January 1, 2010, were found. The main outcome measure was a reduction of pain by ≥50% post-RFA procedure. At 3 months, 7 groups met the criteria and at 6 months, 6 groups met the criteria. A meta-analysis with a forest plot was done at the 3- and 6-month patient follow-up intervals. The associated standard error was calculated for each study group. An overall weighted average with respective standard error was also obtained. A calculation of 95% confidence intervals (95% CI) was then derived. A test for heterogeneity, publication bias, and file drawer effect was also done at the 3- and 6-month intervals. At 3 months, a range of 0.538-0.693 was found to have a 95% CI, with a pooled mean of 0.616. At 6 months, a 95% CI of 0.423-0.576 was found, with a pooled mean of 0.499. The meta-analysis demonstrated that RFA is an effective treatment for SI joint pain at 3 months and 6 months. This study is limited by the available literature and lack of randomized controlled trials. Further standardization of RFA lesion techniques needs to be established, coupled with prospective randomized controlled trials.

Ultrasound-guided interventional procedures in pain medicine: a review of anatomy, sonoanatomy, and procedures. Part II: axial structures

There is a growing trend in using ultrasonography in pain medicine as evident by the plethora of published reports. Ultrasound(US) provides direct visualization of various soft tissues and real-time needle advancement and avoids exposing both the health care provider and the patient to the risks of radiation. The US machine is more affordable and transferrable than fluoroscopy, computed tomography scan,or magnetic resonance imaging machine. In a previous review, we discussed the challenges and limitations of US, anatomy, sonoanatomy, and techniques of interventional procedures of peripheral structures. In the present review, we discuss the anatomy, sonoanatomy, and US-guided techniques of interventional pain procedures for axial structures and review the pertinent literature.

Fluoroscopy-guided sacroiliac joint injections with phenol ablation for persistent sacroiliitis: a case series

In this article we are reporting on the use of fluoroscopy-guided 6% Phenol injections for the ablation of the sacroiliac joints (SIJs), utilizing retrospective review of case reports. We reviewed 10 patients (7 male and 3 female) who have known sacroiliitis proven by fluoroscopically guided sacroiliac joint (SIJ) injection (age ranged from 25 to 78). They all had 2 to 4 weeks of relief after the injections utilizing Bupivacaine 0.5% and 80 mg of depomedrol. They all had repeat fluoroscopy-guided injections of the SIJs with neurolysis of either a unilateral SIJ or bilateral SIJs using 6% Phenol. Phenol 6% with saline 2.5 cc per joint was injected; the needle was cleared with local anesthetic before removing it from the joint. Twenty percent of the patients had a greater than 70% improvement with an average duration of 24 weeks. Sixty percent of the patients had a 50% to 70% improvement with an average duration of 20 weeks. Ten percent had a 20% to 50% improvement with a total duration of 12 1/2 weeks. Ten percent had a less than 20% improvement. With intra-articular injections of phenol for the ablation of the SIJs, we have found a significant improvement in pain relief accompanied by prolonged duration of relief.

Sacroiliac joint pain: anatomy, biomechanics, diagnosis, and treatment

The sacroiliac joint is an underappreciated cause of low back and buttock pain. It is thought to cause at least 15% of low back pain. It is more common in the presence of trauma, pregnancy, or in certain athletes. The pelvic anatomy is complex, with the joint space being variable and irregular. The joint transmits vertical forces from the spine to the lower extremities and has a role in lumbopelvic dynamic motion. History and physical examination findings can be helpful in screening for sacroiliac joint pain, but individual provocative maneuvers have unproven validity. Fluoroscopically guided injections into the joint have been found to be helpful for diagnostic and therapeutic purposes. Conservative treatment, which also can include joint mobilization, antiinflammatory medicines, and sacroiliac joint belts, generally is effective. Surgical arthrodesis should be considered a procedure of last resort.

Transverse morphology of the sacroiliac joint: effect of angulation and implications for fluoroscopically guided sacroiliac joint injection

OBJECTIVE

Effects of angulation of computed tomography (CT) reconstruction plane on sacroiliac (SI) joint morphology were studied, and factors influencing the approach to fluoroscopically guided SI joint injection were assessed.

DESIGN AND PATIENTS

CT scans of pelvises were reformatted on 41 subjects, aged 51.7 (+/-15.1) years. Transverse images were reconstructed at the caudal 3 cm of the SI joint tilting plane of reconstruction from -30 degrees to +30 degrees at 15 degrees increments. Anteroposterior diameter of joint (depth), angle from sagittal plane (orientation angle), and distance from skin were measured. Joint contour was classified, and presence of bone blocking access to the joint was recorded. Comparison between angles were analysed by t-test. Relationships between variables were assessed by a Pearson correlation test.

RESULTS

Depth was shorter with angulation in the inferior direction (P<0.01). Orientation angle increased with superior angulation (P<0.01). Distance from skin increased (P<0.01) with angulation in either direction. Joint contour was significantly different from baseline at each angle (P<0.001) but highly variable. Inferior angulation resulted in interposition of ilium between skin and SI joint, and superior angulation caused bone block due to the lower sacrum. None of these features was identified without tilting of the reconstruction plane, and effects were more pronounced with steeper angulation.

CONCLUSION

Angulation of the reconstruction plane considerably affects the appearance of the sacroiliac joints. By shortening joint depth, an inferiorly directed approach to SI joint injection may make fluoroscopic guidance easier, although associated bony interposition can prevent access to the synovial compartment. A superiorly directed approach is more likely to have adverse effects.

A Randomized Clinical Trial of Manual Versus Mechanical Force Manipulation in the Treatment of Sacroiliac Joint Syndrome

OBJECTIVE

To investigate the effect of instrument-delivered compared with traditional manual-delivered thrust chiropractic adjustments in the treatment of sacroiliac joint syndrome.

METHODS

Prospective, randomized, comparative clinical trial. Sixty patients with sacroiliac syndrome were randomized into two groups of 30 subjects. Each subject received 4 chiropractic adjustments over a 2-week period and was evaluated at 1-week follow-up. One group received side-posture, high-velocity, low-amplitude chiropractic adjustments; the other group received mechanical-force, manually-assisted chiropractic adjustments using an Activator Adjusting Instrument (Activator Methods International, Ltd, Phoenix, Ariz).

RESULTS

No significant differences between groups were noted at the initial consultation for any of the outcome variables. Statistically significant improvements were observed in both groups from the first to third, third to fifth, and first to fifth consultations for improvements (P < .001) in mean numerical pain rating scale 101 (group 1, 49.1-23.4; group 2, 48.9-22.5), revised Oswestry Low Back Pain Disability Questionnaire (group 1, 37.4-18.5; group 2, 36.6-15.1), orthopedic rating score (group 1, 7.6-0.6; group 2, 7.5-0.8), and algometry measures (group 1, 4.8-6.5; group 2, 5.0-6.8) for first to last visit for both groups.

CONCLUSIONS

The results indicate that a short regimen of either mechanical-force, manually-assisted or high-velocity, low-amplitude chiropractic adjustments were associated with a beneficial effect of a reduction in pain and disability in patients diagnosed with sacroiliac joint syndrome. Neither mechanical-force, manually-assisted nor high-velocity, low-amplitude adjustments were found to be more effective than the other in the treatment of this patient population.

Sacroiliac joint injections performed with sonographic guidance

OBJECTIVE

To investigate the feasibility and effectiveness of sonographic guidance for therapeutic intra-articular sacroiliac joint injections in patients with sacroiliitis.

METHODS

Thirty-four consecutive patients with sacroiliitis were enrolled in this study. The synovial portions of 60 sacroiliac joints received injections under sonographic guidance. For treatment, a mixture of a corticosteroid and a local anesthetic was injected intra-articularly. Fluoroscopic spot images were obtained to assess the accuracy of the sonographically guided technique.

RESULTS

Of the 60 sonographically guided injections, 46 (76.7%) were successful (i.e., intra-articular), and 14 (23.3%) were missed. The successful intra-articular injection rate was 60% in the first 30 injections, and it gradually improved, reaching 93.5% in the last 30 injections. The mean procedure time was 9 minutes.

CONCLUSIONS

Our initial experience suggests that sonographically guided therapeutic injections to sacroiliac joints could be valuable alternatives to other guidance modalities in patients with sacroiliitis. In the hands of experienced radiologists, this technique is safe, rapid, and reproducible.

Disorders of the Sacroiliac Joint

Controversies have surrounded the sacroiliac joint. The sacroiliac joint (SIJ) is a considerably complex and strong joint with limited mobility, mechanically serving as a force transducer and a shock absorber. Anatomical changes are seen in the SIJ throughout an individual's lifetime. The ligamentous system associated with the SIJ serves to enhance stability and offer proprioceptive feedback in context with the rich plexus of articular receptors. Stability in the SIJ is related to form and force closure. Movement in the SIJ is 3-D about an axis outside of the joint. The functional examination of the SIJ is related to a clinical triad.