Form and Force Closure of the Sacroiliac Joints

How to inject sacroiliac joints with ultrasound guidance: a pictorial essay

Active sacroiliitis and sacroiliac joint dysfunction represent a common cause of low back pain in the population and are cause of patients' quality of life reduction and disability worldwide. The use of musculoskeletal ultrasound allows to easily identify the sacroiliac joints and to study every pathological condition affecting its most dorsal part; moreover, musculoskeletal ultrasound allows to guide highly effective injective procedures aimed at improving patients' symptoms and enhance their well-being. This paper aims to briefly explain for the musculoskeletal sonographer the anatomy and biomechanics of the sacroiliac joints, the correct ultrasound scanning method for their visualization and the most appropriate ultrasound guided injection technique to help dealing with the diagnostic and management of sacroiliac joint pain in the everyday scenario.

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.

Lumbosacral zone features in individuals with nonspecific chronic low back pain are unique compared to controls and correlate with pain and dysfunction

OBJECTIVES

To compare the lumbosacral nerve distances (LNDs) and sacroiliac joint (SIJ) morphology in individuals with nonspecific chronic low back pain (NSCLBP) and control and examine their correlations with pain and dysfunction in the former.

MATERIALS AND METHODS

The sample includes 200 adult patients (ranging from 20 to 50 years old) referred for computerized abdominal tomography (CT): 100 individuals with NSCLBP (50 males and 50 females) and 100 individuals without NSCLBP (50 males and 50 females). CT scans were assessed for LNDs, degenerative sacroiliac changes, and joint bridging. Those factors were correlated to the outcomes of three self-reported questionnaires about pain and function (Oswestry, Fear-Avoidance, and Numerical Pain Rating Scale) in the NSCLBP group.

RESULTS

Individuals with NSCLBP tend to have reduced LNDs from the sacral part of the SIJ compared to controls (males: right Δ = 5.8 mm, left Δ = 6.03 mm; females: right Δ = 7.9 mm, left Δ = 7.73 mm, two-way ANOVA, p < 0.01), with moderate significant negative correlations with all three questionnaires (-0.38 < Pearson's r < - 0.57, p < 0.02, i.e., reduced LNDs with greater disability and pain). The NSCLBP group had more significant SIJ degeneration severity that moderately correlated with two questionnaires (0.39 < Pearson's r < 0.66, p < 0.04, i.e., greater SIJ degeneration with greater disability and pain). In males, the existence of SIJ bridging strongly correlated with all three questionnaires (0.38 < Pearson's r < 0.78, p < 0.03), and in females, only the Fear-Avoidance Questionnaire and Numerical Pain Scale (0.29 < Pearson's r < 0.41, p < 0.04).

CONCLUSION

Compared to controls, individuals with NSCLBP have reduced LNDs and worse SIJ degenerative changes that correlate with function and pain.

KEY POINTS

• Individuals with nonspecific low back pain tend to have reduced lumbosacral nerve distances than healthy controls. This may be due to entrapments or inflammation of the nerves or surrounding tissues. • Individuals with nonspecific low back pain tend to have more severe degeneration of their sacroiliac joint than healthy controls. • The above findings significantly correlated with the scores of three self-reported questionnaires about pain and function, implicating that they may be of clinical significance.

Effects of Pelvic-Tilt Imbalance on Disability, Muscle Performance, and Range of Motion in Office Workers with Non-Specific Low-Back Pain

Imbalance in the pelvic tilt is considered to be a major variable in low back pain. The purpose of this study was to investigate the effects of pelvic-tilt imbalance on trunk- and hip-muscle performance, range of motion, low-back pain, and the degree of disability in office workers. This was a cross-sectional study conducted in a physical therapy clinic on forty-one office workers diagnosed with non-specific low-back pain. Among the office workers with non-specific low-back pain, 25 were assigned to the pelvic-tilt-imbalance group and 16 to the normal group without pelvic-tilt imbalance. In order to determine the differences according to the imbalance in pelvic tilt, the pain intensity and disability indices were compared between the groups. In addition, the muscle performance and range of motion of the trunk and hip joints and foot pressure were measured and compared. There were differences between the groups in the disability indices and the ratio of internal and external rotation of the hip joint. However, there were no differences in the other variables. Pelvic-tilt imbalance in office workers with non-specific chronic low-back pain may exacerbate the degree of disability and be related to hip-joint rotational range of motion.

Activation of Anterolateral Abdominal Muscles During Sling Bridge Exercises: Comparison of Different Pelvic Positions

CONTEXT

Inappropriate activation of the anterolateral abdominal muscles affects the stability of the lumbopelvic zone and increases the appearance of pain and lesion in the area. Therefore, ways to improve its effective contraction are crucial in rehabilitation. The aim of this study was to compare the activation of the transverse abdominis (TrA), internal oblique (IO), and external oblique (EO) muscles in 3 different pelvic positions (down pelvis [DP], horizontal pelvis [HP], and up pelvis [UP]) during sling bridge exercise (SBE) to determinate which position is more effective to promote a correct contraction of the anterolateral abdominal muscles.

DESIGN

Cross-sectional study.

METHODS

Fifteen participants performed 3 variations (DP, HP, and UP) of a one-legged exercise called "supine pelvic lift" on a sling device. The thicknesses of the TrA, IO, and EO were recorded at rest and at the 3 positions using ultrasound imaging. Thickness, change ratio, lateral slide of TrA, and preferential and contraction activation ratio of TrA, IO, and EO were analyzed.

RESULTS

TrA and IO showed greater activation (P = .01) in the UP position than the other pelvic positions. In addition, UP position decreased the activation of the EO (P = .01).

CONCLUSION

Based on the results of this study, SBE in the UP position has the potential to improve normal contraction patterns of the musculature and can be used in future intervention of the lumbopelvic zone.

What You Need to Know About Sacroiliac Dysfunction

Low back pain is the leading cause of disability worldwide, and sacroiliac dysfunction is estimated to occur in 15%-30% of those with nonspecific low back pain. Nurses are in the unique position to support and provide education to patients who may be experiencing sacroiliac dysfunction or possibly apply this knowledge to themselves, as low back pain is a significant problem experienced by nurses. A patient's clinical presentation, including pain patterns and characteristics, functional limitations, common etiologies and musculoskeletal system involvement, current diagnostic tools, and realm of treatments, are discussed along with their respective efficacy. Distinction is made between specific diagnosis and treatment of joint involvement and that of sacroiliac regional pain, as well as other factors that play a role in diagnosis and treatment for the reader's consideration.

Numerical analysis of the effects of padded pelvic belts as a treatment for sacroiliac joint dysfunction

BACKGROUND: Pain related to the sacroiliac joint (SIJ) accounts for low back pain in 15%–30% of patients. One of the most common treatment options is the use of pelvic belts. Various types of pelvic belts exist; however, the mechanisms underlying treatment and their effectiveness remain unclear to date. OBJECTIVE: To analyze stress distribution in the pelvis when a pelvic rubber belt or a padded pelvic belt is applied, to assess the effectiveness of treatment from a numerical biomechanical perspective. METHODS: The pressure distribution at the pelvic belts was measured using a device and subsequently modeled with the finite element method of a pelvis with soft tissues. The stress environment when wearing a pelvic belt in a double-leg stance was simulated. RESULTS: With the application of pelvic belts, the innominate bone rotated outward, which was termed an out-flare. This caused the SIJ to compress and cause reduction in sacrotuberous, sacrospinous, interosseous, and posterior sacroiliac ligament loading. Padded pelvic belts decreased the SIJ displacement to a greater extent than in pelvic rubber belts. CONCLUSION: Pelvic belts aid in compressing the SIJ and reduce its mobility.

Biomechanical analysis of sacroiliac joint motion following oblique-pulling manipulation with or without pubic symphysis injury

Background: Oblique-pulling manipulation has been widely applied in treating sacroiliac joint (SIJ) dysfunction. However, little is known about the biomechanical mechanism of the manipulation. This study aims to analyze the SIJ motion under oblique-pulling manipulation, in comparison with compression and traction loads.

Methods/Study Design: A total of six specimens of embalmed human pelvis cadavers were dissected to expose the SIJ and surrounding ligaments. Through a servo-hydraulic testing system, biomechanical tests were performed on the stable pelvis and the unstable pelvis with pubic symphysis injury (PSI). A three-dimensional (3D) photogrammetry system was employed to determine the separation and nutation in three tests: axial compression (test A), axial traction (test B), and oblique-pulling manipulation (test C).

Results: After applying the testing loads, the range of nutation was no more than 0.3° (without PSI) and 0.5°(with PSI), separately. Except for test B, a greater nutation was found with PSI (p < 0.05). Under both conditions, nutation following test A was significantly greater than that of other tests (p < 0.05). SIJ narrowed in test A and separated in tests B and C, where the range of motion did not exceed 0.1 mm (without PSI) or 0.3 mm (with PSI) separately. Under both conditions, the separation of SIJ in test C was not as apparent as the narrowness of SIJ in test A (p < 0.05). Compared to SIJ, a more significant increasing displacement was found at the site of the iliolumbar ligament (p < 0.05). Nevertheless, when the force was withdrawn in all tests, the range of nutation and separation of SIJ nearly decreased to the origin.

Conclusion: Pubic symphysis is essential to restrict SIJ motion, and the oblique-pulling manipulation could cause a weak nutation and separation of SIJ. However, the resulting SIJ motion might be neutralized by regular standing and weight-bearing load. Also, the effect on SIJ seems to disappear at the end of manipulation. Therefore, the stretching and loosening of surrounding ligaments need to be paid more attention to.

A patient-cohort study of numerical analysis on sacroiliac joint stress distribution in pre- and post-operative hip dysplasia

In acetabular dysplasia, the cartilaginous roof on the acetabular side does not fully cover the femoral head, which may lead to abnormal stress distribution in both the femoral head and pelvis. These stress changes may have implications to the adjacent sacroiliac joint (SIJ). The SIJ has a minimal range of motion and is closely coupled to the adjacent spine and pelvis. In consequence, the SIJ may react sensitively to changes in stress distribution at the acetabulum, with hypermobility-induced pain. The purpose of this study was to investigate the stress distribution of the SIJ in acetabular dysplasia, and to gain insight into the cause and mechanisms of hypermobility-induced pain at the SIJ. Finite element models of pre- and postoperative pelves of four patients with acetabular dysplasia were created and analyzed in double leg standing positions. The preoperative models were relatively inflare, the sacral nutation movement, SIJ cartilage equivalent stress, and the load on the surrounding ligaments decreased with increased posterior acetabular coverage. Acetabular morphology was shown to affect the SIJ, and improvement of the posterior acetabular coverage may help normalize load transmission of the pelvis and thus improve the stress environment of the SIJ in acetabular dysplasia.

Biomechanical study of anterior and posterior pelvic rings using pedicle screw fixation for Tile C1 pelvic fractures: Finite element analysis

Objective

The purpose of this study was to analyse the biomechanical characteristics of pedicle screws with different placement methods and diameters in the treatment of Tile C1 pelvic fractures by finite element simulation technology and to compare them with the plate fixation model to verify the effectiveness of pedicle screw fixation.

Methods

A three-dimensional digital model of a normal pelvis was obtained using computed tomography images. A finite element model of a normal pelvis containing major ligaments was built and validated (Model 1). Based on the verified normal pelvis finite element model, a Tile C1 pelvic fracture model was established (Model 2), and then a plate fixation model (Model 3) and a pedicle screw fixation model with different screw placement methods and diameters were established (Models 4–15). For all pelvic fracture fixation models, a vertical load of 500 N was applied on the upper surface of the sacrum to test the displacement and stress distribution of the pelvis in the standing state with both legs.

Results

The finite element simulation results showed the maximum displacement of Model 1 and Models 3–15 to be less than 1 mm. The overall maximum displacement of Models 4–15 was slightly larger than that of Model 3 (the maximum difference was 177.91×10⁻³ mm), but the maximum displacement of iliac bone and internal fixation in Models 4–15 was smaller than that of Model 3. The overall maximum stress (maximum stress of the ilium) and maximum stress of internal fixation in Models 4–15 were less than those in Model 3. The maximum displacement difference and maximum stress difference at the fracture of the pubic ramus between each fixed model were less than 0.01 mm and 1 MPa, respectively. The greater the diameter and number of pedicle screws were, the smaller the maximum displacement and stress of the pelvic fracture models were.The maximum displacement and stress of the pelvic fracture models of the screws placed on the injured side of the pubic region were smaller than the screws on the healthy side.

Conclusion

Both the anterior and posterior pelvic rings are fixed with a pedicle screw rod system for treatment of Tile C1 pelvic fractures, which can obtain sufficient biomechanical stability and can be used as a suitable alternative to other implants.The greater the diameter and number of pedicle screws were, the greater the pelvic stability was, and the greater was the stability of the screws placed on the injured side of the pubic region than the screws on the healthy side.

Immediate effect of trunk flexion and extension isometric exercise using an external compression device on electromyography of the hip extensor and trunk range of motion of healthy subjects

Background

Sacroiliac joints (SIJs) transmitted trunk load to lower extremities through the lumbopelvis. External compression devices across the SIJs could provide stability to the SIJs. A previous study established that using a device known as Active Therapeutic Movement version 2 (ATM^®2) has been developed to improve pain and joint range of motion (ROM) in patients with LBP. However, no study has examined the physiological change in the muscle through ATM®2-based exercise thus far. This study aimed to determine the immediate effects of ATM^®2 exercise on the contraction timing, back extension endurance, muscle fatigue, and trunk ROM of lumbar and lower limb muscles in healthy subjects.

Methods

Thirty-six healthy subjects (mean age = 23.16 ± 2.3) volunteered to participate in this study. Subjects were instructed to perform ROM test using sit and reach test, back extensor endurance test using Biering-Sorensen test, erector spinae (ES), lumbar multifidus (LM) fatigue and onset time of Gluteus maximus (GM) in prone hip extension using electromyography before and after trunk flexion and extension isometric exercises.

Results

The ROM in trunk flexion showed a significant increase of 7.9% after exercise compared to that before exercise (p < 0.05). Relative GM contraction onset timing significantly decreased after exercise (p < 0.05). The result of the Sorensen test after exercise showed a trend of increase in duration time. Muscle fatigue in the LM, however, showed a significant increase (p < 0.05), whereas muscle fatigue in the ES was reduced without statistical significance.

Conclusions

The results base on this study showed that exercise-based on ATM®2 is an effective exercise protocol with an effect on the biomechanics of healthy subjects.

Clinical trial registration numbers KCT0006728. Clinical trial registration date: 09/11/2021.

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.

Indicators of motherhood? Sacral preauricular extensions and notches in identified skeletal collections

The sacral preauricular extension (SPE) and sacral preauricular notch (SPN) are morphological changes at the ventral apex of the sacrum. We recently specified their shapes and appearances and suggested a scoring system based on prehistoric Austrian skeletal assemblages. We hypothesized that these specific pelvic changes relate to past pregnancies and parturitions, a hypothesis that we now tested on a subsample of individuals from the Simon Identified Skeletal collection in Geneva (n = 62) and the Christ Church, Spitalfields collection in London (n = 27) linked to historical information on deliveries. We found SPE and SPN in low frequencies and only in female individuals with at least two children in both collections, and a significant association between the emergence of SPE and first births by 25 years. SPN was found only in two females in the Simon collection, but both with a very high number of recorded parturitions including twin births. Based on these results, we are confident in our assumption that at least SPE, and possibly also SPN, result from increased compression forces at the sacroiliac joint, and especially at the ventrosuperior margin, in recurring (complicated) birth events, the interaction of enhanced pelvic joint mobility that is highest up to age 25, and postural changes related to weight gain during pregnancy. Pelvic shape, dimensions, body proportions, biomechanical issues and hormonal levels may also play a role in their emergence.

Pilot Study of Sacroiliac Joint Dysfunction Treated with a Single Session of Fascial Manipulation® Method: Clinical Implications for Effective Pain Reduction

Background and Objectives: Sacroiliac joint dysfunction (SIJD) generally refers to pain in the lower back due to abnormal sacroiliac joint movement, either from hypomobility or hypermobility. It is considered to be the principal cause in up to 40% of low back pain cases. In literature, it emerges that the "fascia", by its anatomical continuity, if altered or densified in different regions of the body with respect to the sacroiliac joint and its surroundings, may have a fundamental role in the genesis of SIJD and low back pain. The purpose of the present study is to evaluate the effectiveness of incorporating a single session of Fascial Manipulation^®-Stecco method^®, treating the muscular fasciae at distance from the painful region. Materials and Methods: Twenty patients with acute and chronic sacroiliac joint dysfunction (SIJD) were recruited (16 males and 4 females, mean age of 46.6 ± 12.98 years). Patients underwent a predefined assessment protocol, followed by an evaluation of myofascial pain and subsequent manipulation of the fascia at points at least 20 cm away from the posterior inferior iliac spines (PIIS). Each patient underwent three pain evaluations: pre-treatment (t0), post-treatment (t1), and at a 1-month follow-up (t2). For the evaluation in t0, t1 the numerical rating scale (NRS) for the intensity of pain and the algometer for the pain threshold at the PIIS were used; in t2 only the NRS scale. Results: The results obtained by comparing the algometer measurements with the NRS values between t0 and t1 were in both cases statistically significant (p < 0.0001), whereas the comparison between the NRS values at t1 and at t2 was not statistically significant (p > 0.05). Conclusions: A single Fascial Manipulation treatment, even when applied at least 20 cm from the PIIS, can potentially decrease pain around the SIJ. The inclusion of this type of approach in SIJD can allow for improved patient management, better tolerance for other treatments and a more rapid application of pain-free exercise programs.

Schlüsselregion Becken

Hintergrund

Beckenringdysfunktionen sind eine der häufigsten Ursachen für Arbeitsausfälle weltweit. Neben muskuloskeletalen können viszerale Beschwerden der Beckenorgane auftreten. Der Beitrag erläutert den aktuellen Wissensstand zur funktionellen Anatomie des Beckens, beschreibt einige typische Beschwerdebilder aus gynäkologischer/geburtshilflicher Sicht sowie eine manuelle Methode zur nachhaltigen Beschwerdelinderung.

Fragestellung

Welche viszeralen Beschwerdebilder werden durch eine Beckenringdysfunktion (mit)verursacht? Wie kann eine manuelle Methode aussehen, die nachhaltig zur Verminderung der Beschwerden und Verbesserung der Lebensqualität beiträgt?

Methode

Der heutige Wissensstand der funktionellen Anatomie des Beckens wird mit den entsprechenden Beschwerdebildern bei Beckenringdysfunktionen dargelegt. Der Fokus liegt neben muskuloskeletalen speziell auch auf viszeralen Problemen wie vorzeitige Kontraktionen, Geburtsproblemen, Dysmenorrhö, Obstipation, Harndrang, Dyspareunie und Fertilitätsprobleme.

Ergebnisse

Beschwerdelinderung, Zunahme der Lebensqualität und bessere Funktion der Beckenorgane nach manueller Therapie und Stabilisierung des Beckenrings zeigen sich in einzelnen Fallbeispielen und insgesamt bei der Klientel der Grundversorgerpraxis.

Schlussfolgerung

Das Becken ist eine Schlüsselregion für die manuelle Medizin. Verschiedenste Beschwerdebilder können durch eine manuelle Behandlung deutlich reduziert werden.

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.

The Cranial Bowl in the New Millennium and Sutherland's Legacy for Osteopathic Medicine: Part 2

Cranial osteopathic medicine is practiced all over the world, respecting the dictates of the creator, Dr Sutherland. Despite the current manual approach faithfully follows the theoretical and practical bases that make up the cranial model of the last century, there are many scientific evidences that highlight the criticalities of the same model. In the first part we reviewed the role of the meninges and cerebrospinal fluid (CSF), as well as we discussed some rhythms present in the central nervous system; these latter elements are the pillars to support the theoretical idea of the movement of the skull evaluated and palpated by the osteopath. In this second part we will review the mechanical characteristics of other structures that make up the cranial system, highlighting new perspectives for clinical practice, thanks to the most recent data derived from scientific research.

Subchondral bone strength of the sacroiliac joint-a combined approach using computed tomography osteoabsorptiometry (CT-OAM) imaging and biomechanical validation

Bone mineral density distribution patterns at the sacroiliac joint (SIJ) may reflect long-term adaptation patterns to the loading the joint endures. This study aims to display bone mineralisation patterns of the articular SIJ subchondral lamella using computed tomography (CT) osteoabsorptiometry and mechanical indenting, to determine whether a relationship exists between mineralisation and mechanical strength. Twenty hemipelves were CT-scanned before osteoabsorptiometry densitograms were derived. Each articular side of eleven SIJs was mechanically indented following a 10-mm grid scheme. The sacral surface displayed lower Hounsfield unit (HU) values (≤ 700 HU) than the iliac side (> 700 HU). The apex, superior corner and borders yielded the highest HU scores (> 700 HU). Penetration strength was significantly higher on the iliac side (p < 0.04). Mineral density correlated positively with penetration strength of the subchondral bone layer (p < 0.05). No correlations were found between the HU values, nor between penetration strength of corresponding sides of the same SIJ in the majority of cases (p > 0.05). The iliac subchondral lamella is mechanically denser than the sacral aspect. The non-correlation between density and bone strength of articulating sides indicates biomechanical non-conformity. Loading throughout the SIJ may follow a complex distribution pattern involving the surrounding soft tissues, suspending the sacrum between the ilia.