MRI of the pelvic ring joints postpartum: normal and pathological findings

Imaging of Sacroiliac Pain: The Current State-of-the-Art

Pain in the sacroiliac (SI) region is a common clinical manifestation, often caused by diseases involving the SI joints. This is typically due to inflammation or degenerative changes, while infections or cancer are less frequent causes. The SI joint is challenging to image accurately because of its distinct anatomical characteristics. For an accurate diagnosis, conventional radiography often needs to be supplemented with more precise methods such as magnetic resonance imaging (MRI) or computed tomography (CT). Sacroiliitis, a common presenting feature of axial spondyloarthritis (axial SpA), manifests as bone marrow edema, erosions, sclerosis, and joint space narrowing. Septic sacroiliitis and repetitive stress injuries in sports can also cause changes resembling inflammatory sacroiliitis. Other conditions, such as osteitis condensans ilii (OCI), can mimic the radiologic characteristics of sacroiliitis. Inflammatory lesions are diagnosed by concurrent erosions, hyperostosis, and ankylosis. Ligament ossifications or mechanical stress can also result in arthritic disorders. Determining the exact diagnosis can be aided by the distribution of the lesions. Inflammatory lesions can affect any part of the articulation, including the inferior and posterior portions. Mechanical lesions, such as those seen in OCI, often occur in the anterior middle region of the joint. In cases of idiopathic skeletal hyperostosis, ligament ossification is found at the joint borders. This pictorial essay describes common SI joint problems, illustrated with multimodal imaging data. We, also, discuss strategies for selecting the best imaging modalities, along with imaging pitfalls, key points, and approaches for treating patients with suspected inflammatory back pain.

The interpubic cavity: A scoping review

The interpubic cavity (cleft) is a narrow, slit-like, oval-shaped cavity which has frequently been described within the fibrocartilaginous interpubic disc. The aim of this article is to thoroughly analyze what is known about the interpubic cavity. The following three scientific databases (PubMed, Web of Science and Google Scholar) were systematically searched. Combinations of the search terms "interpubic cleft", "interpubic cavity", "symphysis pubis cleft", "symphysis pubis cavity" and "symphysis cleft sign" were used. All databases were searched from inception until August of 2022. Searching of the three databases resulted in 711 hits, of which 280 remained after checking for duplicates. In the first step, 152 studies were excluded due to irrelevant content. Thus, 128 proceeded to the second step, of which 23 were finally selected for meeting the objectives of this review. Until now the reason for the cavity forming remains unclear. The interpubic cavity is present in the anterior portion of the interpubic disc, within 2 mm from its anterior margin. There is no predilection in the craniocaudal dimension. The secondary cavity is usually called a "cleft sign". The results of our scoping review summarize information about the interpubic cavity. Its composition and morphology are still not well understood.

Predicting the shape, size, and placement of adult human pubic symphyses

OBJECTIVES

When reconstructing fossil pelves, the articulation of the pelvic bones largely relies on subjective decisions by researchers. Different positionings at the pubic symphysis can affect the overall morphology of the pelvis and the subsequent biological interpretation associated with that individual or species. This study aims to reduce this subjectivity using quantitative models to predict pubic symphysis morphology.

METHODS

We collected 3D landmarks and semilandmarks on the pubic symphysis and adjacent aspects on the CT scans of 103 adults. Using geometric morphometrics we, (1) quantified pubic symphysis morphology, (2) trained simple and two-stage least-squares linear regression models to predict pubic symphysis shape, and (3) assessed the shape variation in the sample. The model with the lowest prediction error was identified as the best model. Principal components analysis was used to explore the effects of each variable on shape and hypothetical shapes were generated from the model to illustrate these effects.

RESULTS

The best model is a two-stage least-squares model that predicts pubic symphysis size at the first stage using additive effects of sex and age, then subsequently interacts pubic symphysis size with sex and age at the second stage to predict pubic symphysis shape. Other models with low prediction errors included variables reflecting pelvic size and breadth.

CONCLUSION

Linear regression modeling can be used to systematically predict pubic symphysis morphology. This method can be used in addition to other techniques to improve fossil reconstructions by more accurately estimating the morphology of this region of the pelvis.

Peripartum Pubic Symphysis Diastasis

Importance

Peripartum separation of the pubic symphysis is a rare but potentially severe complication of childbirth, which may lead to prolonged immobilization. Thus, prompt diagnosis and treatment are paramount.

Objective

The purpose of this review is to define peripartum separation of the pubic symphysis and provide a thorough review of its etiology, clinical manifestations, diagnostic imaging techniques, management, and prognosis.

Evidence Acquisition

This was a literature review using PubMed and Google Scholar.

Results

Peripartum pubic symphysis separation is defined as disruption of the pubic symphysis joint and ligamentous structures with greater than 1 cm of separation during delivery. Risk factors include fetal macrosomia, nulliparity, and precipitous labor. Patients often present with a sensation of something "giving way" in the pubic symphysis area at the time of delivery, or with severe pain in the pubic symphysis region with attempted mobilization postpartum. In severe cases, associated hematomas, pelvic fractures, sacroiliac joint disruption, and urinary tract injury may be seen. Imaging such as x-ray or ultrasound may be used to confirm the diagnosis. Although most patients recover well with conservative management, orthopedic surgical intervention may be indicated in more severe or unresolved cases.

Conclusions and Relevance

Pubic symphysis separation is increasingly identified peripartum due enhanced accessibility and utilization of imaging modalities. It can be debilitating and lead to prolonged immobility postpartum. Therefore, early recognition and diagnosis are important, as this can guide decision-making for management. A multidisciplinary team approach, including coordination with obstetrics, orthopedic surgery, physical therapy, and occupational therapy should be used for early detection and treatment to ensure optimal patient outcomes.

Diagnostics of Sacroiliac Joint Differentials to Axial Spondyloarthritis Changes by Magnetic Resonance Imaging

The diagnosis of axial spondyloarthritis (axSpA) is usually based on a pattern of imaging and clinical findings due to the lack of diagnostic criteria. The increasing use of magnetic resonance imaging (MRI) of the sacroiliac joints (SIJ) to establish the diagnosis early in the pre-radiographic phase has resulted in a shift in the paradigm with an increasing frequency of axSpA diagnoses and a changed sex distribution. Non-radiographic axSpA affects males and females nearly equally, whereas ankylosing spondylitis predominantly occurs in males. The MRI-based increasing frequency of axSpA in women is mainly due to the presence of subchondral bone marrow edema (BME) on fluid-sensitive MR sequences, which may be a non-specific finding in both women and men. Due to the somewhat different pelvic tilt and SIJ anatomy, women are more prone than men to develop strain-related MRI changes and may have pregnancy-related changes. Awareness of non-specific subchondral BME at the SIJ is important as it can imply a risk for an incorrect SpA diagnosis, especially as the clinical manifestations of axSpA may also be non-specific. Knowledge of relevant MRI and clinical features of differential diagnoses is needed in the diagnostic workout of patients with suspected axSpA considering that non-SpA-related SIJ conditions are more common in patients with low back or buttock pain than axSpA sacroiliitis. The purpose of this review was to present current knowledge of the most frequent differential diagnoses to axSpA sacroiliitis by MRI taking the clinical characteristics into account.

A Morphologic Analysis of the Pubic Symphysis Using CT and MRI

INTRODUCTION

The goal of this study was to investigate prevalence and morphometric parameters of pubic ligaments and the interpubic disk and its cavity using imaging methods for use in clinical medicine.

METHODS

Pubic symphysis morphology was investigated in 652 patients (348 women and 304 men), from which 449 CT scans and 203 MR scans were available. The average age of men was 48 years and women 39 years. Investigated parameters included dimensions of the interpubic disk, visibility and width of the reinforcing ligaments, and visibility, dimensions, and location of the symphysial cavity. The results were compared with MR scans of 20 healthy volunteers and 21 dissected anatomic specimens.

RESULTS

The craniocaudal, ventrodorsal, and mediolateral diameters of the pubic disk were 36 to 37.7, 14.8 to 15.2, and 2.2 to 4.2 mm in women and 42 to 42.3, 18.6 to 19, and 2.4 to 4.5 mm in men, respectively. Higher age correlated with shorter mediolateral diameter and larger craniocaudal and ventrodorsal diameters. The superior pubic ligament was visible in 93.1% of men (1.44 mm thick) and in 100% of women (1.7 mm); the inferior pubic ligament in 89.7% of men (1.74 mm) and 88% of women (1.95 mm), the anterior pubic ligament in 96.6% of men (1.5 mm) and 82% of women (1.34 mm); and the posterior pubic ligament in 65.5% of men (1.18 mm) and 63.7% of women (0.83 mm). A symphysial cavity was found in 24% of men and 22.9% of women, with craniocaudal, ventrodorsal, and mediolateral dimensions of 13, 10.7, and 3.2 mm in men and 9.5, 10.7, and 3 mm in women, respectively.

CONCLUSION

The presented morphologic parameters provide an anatomic reference for diagnostics of pathologic conditions of the pubic symphysis. The following anatomic structures should be added to the official anatomic terminology: symphysial cavity (cavitas symphysialis), retropubic eminence (eminentia retropubica), anterior pubic ligament (ligamentum pubicum anterius), and posterior pubic ligament (ligamentum pubicum posterius).

LEVEL OF EVIDENCE

II-III.

Pregnancy-related sacroiliac joint findings in females with low back pain: a four-year magnetic resonance imaging follow-up study

BACKGROUND

Pregnancy-related pain may be associated with sacroiliac joint (SIJ) changes, detectable by magnetic resonance imaging (MRI).

PURPOSE

To analyze the prevalence and course of SIJ MRI and clinical findings in women referred with low back pain and relate these to pregnancy.

MATERIAL AND METHODS

A retrospective follow-up study from a longitudinally collected cohort comprising 328 women.

RESULTS

Women reporting debut of pain in relation to a pregnancy (PP group) tended to have a higher baseline prevalence of all investigated MRI findings, cumulated positive SIJ tests, and a potential fulfilment of the spondyloarthritis diagnosis compared to remainders. The prevalence of subchondral bone marrow edema (BME), any SIJ MRI finding, and potential fulfilment of the spondyloarthritis diagnosis were significantly higher in the PP group compared to women who had not been pregnant. In the total study group, the prevalence of ≥1 MRI finding increased over the four-year study period from 34% to 47% (P<0.001), driven by increasing prevalence of BME (25% to 32%; P=0.008) and fatty marrow deposition (FMD) (20% to 25%; P=0.020). In addition, the BME volume score increased. Over time, the PP group had persisting high prevalence of buttock pain and total MRI findings and their FMD volume score increased, but there were no between-group differences in MRI variables at follow-up.

CONCLUSION

Overall, the prevalence of MRI findings increased over time. Although the PP group had different clinical and SIJ MRI characteristics cross-sectional at baseline compared to remainders, longitudinal analyses revealed that these diminished over time.

Clinical characteristics, treatment and outcomes of acute postpartum inflammatory sacroiliitis: a retrospective study

PURPOSE

We performed this research to report the clinical characteristics and clinical therapeutic strategies of acute postpartum inflammatory sacroiliitis.

METHODS

We retrospectively analyzed the data of patients diagnosed with acute postpartum inflammatory sacroiliitis from 2014 to 2020. All their clinical details including clinical symptoms and signs, laboratory tests, radiologic examination, diagnosis and treatment process and clinical outcomes were obtained and analyzed in this retrospective analysis.

RESULTS

Eleven patients diagnosed with acute postpartum inflammatory sacroiliitis complain of low back pain. Magnetic resonance imaging (MRI) is useful in diagnosing acute postpartum inflammatory sacroiliitis. The systemic non-steroidal anti-inflammatory drugs (NSAIDs) administration, sacroiliac joint injection, and physical therapy effectively alleviated the pain with symptoms disappearing, and the abnormal signal reduced in MRI.

CONCLUSION

Acute postpartum inflammatory sacroiliitis is an uncommon disease with atypical symptoms. MRI examination may be the best diagnostic method. General NSAIDs and sacroiliac joint injections of local anesthetic plus corticosteroid under the guidance of fluoroscopy or ultrasound can achieve safe and effective treatment. This retrospective study was approved by the Committee on the Ethics of our hospital (No. 202101023).

TRIAL REGISTRY

Trial registration was performed in the Chinese Clinical Trial Registry ( http://www.chictr.org.cn , No. ChiCTR2100045656).

MRI of sacroiliac joints for the diagnosis of axial SpA: prevalence of inflammatory and structural lesions in nulliparous, early postpartum and late postpartum women

OBJECTIVES

To determine the prevalence of bone marrow oedema (BME) at the sacroiliac joint (SIJ) in early postpartum (EPP), nulliparous (NP) and late postpartum (LPP) women, and to identify factors associated with BME presence at the SIJ.

METHODS

Three groups were obtained: NP (never given birth), EPP (given birth within 12 months) and LPP (given birth more than 24 months). The primary outcome was the presence of BME and/or structural lesions (erosions, osteophytes, ankylosis and sclerosis) at the SIJ MRI.

RESULTS

BME prevalence was greater among EPP (33%) than NP (14%, p=0.001), but was not different to LPP (21%, p=0.071). The Assessment of SpondyloArthritis international Society (ASAS) MRI criteria for sacroiliitis were positive in 75%, 71% and 80%, respectively, of EPP, NP and LPP women with BME. EPP (38%) had similar prevalence of sclerosis than LPP (28%, p=0.135), but greater than NP (18%, p=0.001). Lastly, EPP (28%) had similar prevalence of osteophytes than LPP (42%) and NP (27%), although there was a difference between LPP and NP (p=0.006).

CONCLUSIONS

EPP have higher BME prevalence at the SIJ than NP, EPP tend to have higher BME prevalence compared with LPP and BME presence decreases with time from delivery. Three-quarters of women with BME at the SIJ had a positive ASAS MRI criteria for sacroiliitis, indicating that BME presence as the main criterion for a positive diagnosis can lead to false-positive results. SIJ MRIs should not be interpreted in isolation, since age, time from delivery and other factors may outweigh the pertinence of MRI findings. Trial registration number NCT02956824.

The effects of pelvic belt use on pelvic alignment during and after pregnancy: a prospective longitudinal cohort study

Background

Pelvic alignment changes during pregnancy and post-childbirth. Pelvic belts exert external forces that compress and stabilize the joints, and therefore, could influence pelvic alignment. However, limited information is available regarding this potential effect. Therefore, the purpose of this study is to investigate the influence of pelvic belt use on pelvic alignment during and after pregnancy.

Methods

Data of 201 pregnant women in late pregnancy and 1 month after childbirth were used. Pelvic alignment measurements, including anterior and posterior pelvic width, pelvic asymmetry, and pelvic belt use during and after pregnancy were investigated. Participants were divided into four groups according to pelvic belt use: before and after childbirth (BAC), before childbirth only (BC), after childbirth only (AC), and non-use (NU). Then, an initial one-way ANOVA was conducted to compare the amount of change in pelvic alignment from late pregnancy to post-childbirth between the groups. After the initial analysis, a multivariate regression analysis was performed to determine the statistically significant differences between the groups to consider other factors that influenced pelvic alignment such as age, BMI, number of previous childbirths, vaginal delivery and pelvic asymmetry in late pregnancy. Next, a cutoff point for subgroup stratification based on the weekly duration of pelvic belt use and inter-group changes in pelvic alignment were compared.

Results

As the result of the initial one-way ANOVA, the decrease in pelvic asymmetry from during pregnancy to postpartum for BAC was greater than that for AC. Moreover, multiple regression analysis showed that the effect of pelvic belt that was revealed in the initial analysis was statistical significance even after adjustment for other factors. Moreover, pelvic asymmetry in the BAC group decreased, compared to being increased or unchanged in the NU and AC groups when the group cutoff time was 7 h per week.

Conclusions

Continuous and extended use of pelvic belts during and after pregnancy might be related to modifications of pelvic asymmetry in the perinatal period. Therefore, the instruction of correct and comfortable usage and the recommendation of continuous use of pelvic belt especially during pregnancy are required for prevention of some discomforts related to pelvic malalignment.

Electronic supplementary material

The online version of this article (10.1186/s12884-019-2457-6) contains supplementary material, which is available to authorized users.

Postpartum Bone Marrow Edema at the Sacroiliac Joints May Mimic Sacroiliitis of Axial Spondyloarthritis on MRI

OBJECTIVE

The objective of our study was to compare MRI findings in the sacroiliac joints of postpartum women (as a model of mechanical changes) and women with known axial spondyloarthritis (as an inflammatory model).

SUBJECTS AND METHODS

For this prospective multicenter age-matched, case-control study, sacroiliac joint MRI examinations of 30 healthy women (mean age, 34.0 years) in the early postpartum period (mechanical group) and 30 age-matched women (mean age, 33.8 years) with known axial spondyloarthritis (retrospective inflammatory group) were compared. Blinded to clinical information, readers assessed MR images using the following scoring systems: Spondyloarthritis Research Consortium of Canada (SPARCC) MRI index, Berlin method, Assessment of Spondyloarthritis International Society (ASAS) criteria, and SPARCC MRI structural score. Descriptive statistics as percentages of the different findings (i.e., bone marrow edema [BME], erosion, fatty bone marrow replacement, backfill, ankylosis) and scores between groups and between delivery modes were compared.

RESULTS

In the postpartum group, 63.3% (19/30) of women showed BME around the sacroiliac joints compared with 86.7% (26/30) of women in the spondyloarthritis group (based on ASAS criteria). Erosions were uncommon in the postpartum group (10.0% [3/30] postpartum vs 56.7% [17/30] spondyloarthritis). Fatty bone marrow replacement, backfill, and ankylosis were not seen in the postpartum group. In subjects with positive MRI findings for sacroiliitis based on ASAS criteria, the SPARCC MRI index (mean ± SD, 13.6 ± 14.5 vs 13.0 ± 10.7; p = 0.818) and Berlin method (4.5 ± 3.0 and 5.5 ± 3.5, p = 0.378) were not different between the postpartum and spondyloarthritis groups. Scores were not different between birth modalities.

CONCLUSION

Pregnancy-induced BME at the sacroiliac joints, as a result of prolonged mechanical stress, was present in 63.3% of women who underwent MRI during the early postpartum period and may mimic sacroiliitis of axial spondyloarthritis.

Acute Intrapartum Rupture of the Pubic Symphysis Requiring Resuscitation and Surgical Intervention: A Case Report

BACKGROUND

Pubic symphysis rupture significant enough to cause serious complications or require surgical intervention is exceedingly rare. Here we review the literature and examine the details of a unique presentation.

CASE

A 27-year-old woman presented in labour at 34+6 weeks gestation after an uncomplicated monochorionic-diamniotic twin pregnancy. After vaginal delivery, she developed a substantial labial hematoma. Hours later, she became hemodynamically unstable. Imaging revealed a 4.7-cm pubic diastasis and a small arterial tear. One week later, the diastasis had expanded to 6 cm on X-ray. As a result, the patient underwent surgical intervention. She was discharged home on postpartum day 21 and remained non-weight-bearing for 8 weeks.

CONCLUSION

Pubic symphysis rupture is a potentially life-threatening obstetrical complication that requires early recognition and effective multidisciplinary care.

Pubic Symphysis Rupture and Separation During Pregnancy

OBJECTIVE

The aim of this study was to determine the risk factors, clinical and radiologic criteria for diagnosis, and management of this unusual complication of pregnancy.

METHODS

A PubMed and Web of Science search was undertaken with no limitations on the number of years searched.

RESULTS

There were 36 publications identified, with 19 articles being the basis of this review. Multiple risk factors have been identified including multiparity, macrosomia, cephalopelvic disproportion, forceps deliveries, precipitous labor, malpresentation, prior pelvic trauma, and use of the McRoberts maneuver. The diagnosis is usually made clinically, confirmed by imaging, and considered pathological when the intrapubic gap is greater than 10 mm. Magnetic resonance imaging appears to be superior to pelvic x-ray and computed tomography scan in visualization of the bone separation. Conservative treatment remains the first choice for therapy, but women who do not respond to conservative therapy or women with large separations may need surgical stabilization with external or internal fixation.

CONCLUSIONS

Widening of the pubic symphysis greater than 10 mm is pathologic. The diagnosis is clinical and confirmed by imaging studies, with magnetic resonance imaging being the superior technique. Conservative treatment is the first line of therapy. Failure of conservative therapy is treated by surgical stabilization.

Diastasis of symphysis pubis and labor: Systematic review

Symphysis pubis diastasis (SPD) is an infrequent complication of labor that can impair womens' general health through failure of the passive stability of the pelvic girdle. Although conservative approaches are often used to decrease symptoms and interpubic separation, notably few studies have analyzed the effect of these methods on managing the symptoms of women with SPD. The purpose of this study was to review the available literature on the conservative treatment of SPD during pregnancy and labor. A computer-based search using PubMed, PEDro, and CINAHL was performed up to November 2014. We selected all studies that considered women with SPD during pregnancy or labor and treated them with conservative methods and excluded those that included surgical intervention. Eighteen studies were selected, most of which were case reports. Although the overall results of conservative treatment were unclear because of the type and design of the obtained studies, most of the studies reported bed rest in the lateral decubitus position and a pelvic girdle as basic treatments. Additionally, the few clinical trials reported recommended additional physiotherapy, including strengthening and stabilizing exercises, to reduce SPD symptoms.

Assessment of postpartum symphysis pubis distention with 3D ultrasonography: a novel method

OBJECTIVES

Determining the accuracy of three-dimensional (3D) sonographic measurement of symphysis pubis (SP) distension in comparison to plain X-ray pelvic radiographs and assessing the interperformer reliability of this method.

METHODS

Pelvic X-ray was performed on 86 women who delivered singleton babies within 36 h of delivery then each woman was examined by 3D transperineal ultrasound imaging by two sonogrographers.

RESULTS

Measurements of SP with 3D transperineal ultrasonography in comparison to pelvic X-ray showed 95% limits of agreement. Interperformer reproducibility was substantial (interclass correlation coefficient 0.66-0.70) for measures of SP.

CONCLUSIONS

Pubic symphysis width, superior pubic ligament length, and SP height can be reliably measured with 3D ultrasonography.

The effect of factors other than age upon skeletal age indicators in the adult

CONTEXT

Estimation of adult age from skeletal remains is problematic due to the weak and variable relationship between age indicators and age.

OBJECTIVES

To assess the proportion of variation in age indicators that is associated with factors other than age and to attempt to identify what those factors might be.

METHODS

The paper focuses on frequently used adult bony age markers. A literature search (principally using Web of Science) is conducted to assess the proportion of variation in age indicators associated with factors other than age. The biology of these age markers is discussed, as are factors other than age that might affect their expression.

RESULTS

Typically, ∼60% of variation in bony age indicators is associated with factors other than age. Factors including inherent metabolic propensity to form bone in soft tissue, vitamin D status, hormonal and reproductive factors, energy balance, biomechanical variables and genetic factors may be responsible for this variation, but empirical studies are few.

CONCLUSION

Most variation in adult skeletal age markers is due to factors other than age; dry bone study of historic documented skeletal collections and high resolution CT scanning in modern cadavers or living individuals is needed to identify these factors.

Prevalence of degenerative and spondyloarthritis-related magnetic resonance imaging findings in the spine and sacroiliac joints in patients with persistent low back pain

OBJECTIVE

To estimate the prevalence of degenerative and spondyloarthritis (SpA)-related magnetic resonance imaging (MRI) findings in the spine and sacroiliac joints (SIJs) and analyse their association with gender and age in persistent low back pain (LBP) patients.

METHODS

Degenerative and SpA-related MRI findings in the whole spine and SIJs were evaluated in Spine Centre patients aged 18-40 years with LBP.

RESULTS

Among the 1,037 patients, the prevalence of disc degeneration, disc contour changes and vertebral endplate signal (Modic) changes were 87 % (±SEM 1.1), 82 % (±1.2) and 48 % (±1.6). All degenerative spinal findings were most frequent in men and patients aged 30-40 years. Spinal SpA-related MRI findings were rare. In the SIJs, 28 % (±1.4) had at least one MRI finding, with bone marrow oedema being the most common (21 % (±1.3)). SIJ erosions were most prevalent in patients aged 18-29 years and bone marrow oedema in patients aged 30-40 years. SIJ sclerosis and fatty marrow deposition were most common in women. SIJ bone marrow oedema, sclerosis and erosions were most frequent in women indicating pregnancy-related LBP.

CONCLUSION

The high prevalence of SIJ MRI findings associated with age, gender, and pregnancy-related LBP need further investigation of their clinical importance in LBP patients.

KEY POINTS

• The location of vertebral endplate signal changes supports a mechanical aetiology. • Several sacroiliac joint findings were associated with female gender and pregnancy-related back pain. • Sacroiliac joint bone marrow oedema was frequent and age-associated, indicating a possible degenerative aetiology. • More knowledge of the clinical importance of sacroiliac joint MRI findings is needed.

Sonographic anatomy of the pubic symphysis in healthy nulliparous women

Pregnancy-related symphyseal pain is a condition commonly encountered by clinicians but its pathogenesis is poorly understood. The pubic symphysis is readily visualized with ultrasound, yet the normal sonographic anatomy of the joint has not been accurately documented. This study aimed to describe the anatomy of the pubic symphysis in healthy, nulliparous women using ultrasound. An experienced and inexperienced sonographer scanned the joint in 30 female volunteers (mean age 26 years). Interobserver and intraobserver reliability of ultrasound measurements were examined and the accuracy of these measurements was validated by ultrasound and dissection of six female cadaver pelves (mean age 75 years). In healthy young women, pubic symphysis morphology varied, and six categories of anterosuperior joint shape were defined. Mean values of several anatomic parameters were obtained in supine and standing positions: joint width (widest 10.1 mm, narrowest 2.6 mm); superior pubic ligament (SPL) length and depth (41.4 and 3.4 mm, respectively); and pubic crest length (left 24.4 mm, right 24.4 mm). Statistically significant relationships between SPL width and depth and anthropometric variables (body mass index, pelvic width, and body fat percentage) were established. Larger ultrasonographic measurements, such as wide joint width and SPL length, could be measured more reliably than smaller measurements, such as narrow joint width and SPL depth, in both healthy volunteers and cadavers. Findings from this study provide normative reference data for examination of the pubic symphysis in pregnant women and may therefore be relevant to understand pregnancy-related symphyseal pain.

Imaging of musculoskeletal disorders related to pregnancy

OBJECTIVE

This article provides an overview of the typical appearance of biomechanical and physiologic changes in pregnancy and an update on related pathophysiology. Conditions occurring during the childbearing, delivery and postpartum periods will be reported separately.

CONCLUSION

Pregnancy causes biomechanical and physiologic changes that may be responsible for a wide spectrum of musculoskeletal disorders in the mother.

Hormonal contraception and pelvic girdle pain during pregnancy: a population study of 91,721 pregnancies in the Norwegian Mother and Child Cohort

STUDY QUESTION

Is pre-pregnancy hormonal contraception use associated with the development of pelvic girdle pain during pregnancy?

SUMMARY ANSWER

In contrast to combined oral contraceptive pills, long lifetime exposure to progestin-only contraceptive pills or the use of a progestin intrauterine device during the final year before pregnancy were associated with pelvic girdle pain.

WHAT IS ALREADY KNOWN

Pelvic girdle pain severely affects many women during pregnancy. Smaller studies have suggested that hormonal contraceptive use is involved in the underlying mechanisms, but evidence is inconclusive.

STUDY DESIGN, SIZE, DURATION

A population study during the years 1999-2008.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A total of 91,721 pregnancies included in the Norwegian Mother and Child Cohort Study. Data were obtained by two self-administered questionnaires during pregnancy weeks 17 and 30.

MAIN RESULTS AND THE ROLE OF CHANCE

Pelvic girdle pain was present in 12.9% of women who had used combined oral contraceptive pills during the last pre-pregnancy year, 16.4% of women who had used progestin-only contraceptive pills, 16.7% of women who had progestin injections and 20.7% of women who had used progestin intrauterine devices, compared with 15.3% of women who did not report use of hormonal contraceptives. After adjustment for other study factors, the use of a progestin intrauterine device was the only factor based on the preceding year associated with pelvic girdle pain [adjusted odds ratios (OR) 1.20; 95% confidence interval (CI): 1.11-1.31]. Long lifetime exposure to progestin-only contraceptive pills was also associated with pelvic girdle pain (adjusted OR 1.49; 95% CI: 1.01-2.20).

LIMITATIONS, REASONS FOR CAUTION

The participation rate was 38.5%. However, a recent study on the potential biases of skewed selection in the Norwegian Mother and Child Cohort Study found the prevalence estimates but not the exposure-outcome associations to be influenced by the selection.

WIDER IMPLICATIONS OF THE FINDINGS

The results suggest that combined oral contraceptives can be used without fear of developing pelvic girdle pain during pregnancy. However, the influence of progestin intrauterine devices and long-term exposure to progestin-only contraceptive pills requires further study.

STUDY FUNDING/COMPETING INTEREST(S)

The present study was supported by the Norwegian Research Council. None of the authors has a conflict of interest.

Pubic bone injuries in primiparous women: magnetic resonance imaging in detection and differential diagnosis of structural injury

OBJECTIVE

To evaluate the utility of magnetic resonance imaging (MRI) in diagnosing structural injury in primiparous women at risk for pelvic floor injury.

METHODS

This was an observational study of 77 women who underwent 3T MRI after delivery. Women were operationally defined as high risk (n = 45) for levator ani muscle tears (risk factors: second-stage labor > 150 min or < 30 min, anal sphincter tear, forceps, maternal age > 35 years and birth weight > 4000 g) or low risk (n = 32): vaginally delivered without these risk factors (n = 12); delivered by Cesarean section after second-stage labor > 150 min (n = 14) or delivered by Cesarean section without labor (n = 6). All women were imaged using fluid-sensitive MRI sequences. Two musculoskeletal radiologists reviewed images for bone marrow edema, fracture, pubic symphysis measurements and levator ani tear.

RESULTS

MRI showed pubic bone fractures in 38% of women at high risk for pelvic floor injury and in 13% of women at low risk for pelvic floor injury (χ(2) (3) = 9.27, P = 0.03). Levator ani muscle tears were present in 44% of the high-risk women and in 9% of the low-risk women (χ(2) (3) = 11.57, P = 0.010). Bone marrow edema in the pubic bones was present in 61% of women studied across delivery categories. Complex patterns of injury included combinations of bone marrow edema, fractures, levator ani tears and pubic symphysis injuries. No MRI-documented injuries were present in 18% of women at high risk and 44% at low risk for pelvic floor injury (χ(2) (1) = 6.2, P = 0.013).

CONCLUSIONS

Criteria identifying primiparous women at risk for pelvic floor injury can predict increased risk of bone and soft tissue changes at the pubic symphysis. Fluid-sensitive MRI has utility for differential diagnosis of structural injury in postpartum women.

Pregnancy-related pelvic girdle pain: an update

A large number of scientists from a wide range of medical and surgical disciplines have reported on the existence and characteristics of the clinical syndrome of pelvic girdle pain during or after pregnancy. This syndrome refers to a musculoskeletal type of persistent pain localised at the anterior and/or posterior aspect of the pelvic ring. The pain may radiate across the hip joint and the thigh bones. The symptoms may begin either during the first trimester of pregnancy, at labour or even during the postpartum period. The physiological processes characterising this clinical entity remain obscure. In this review, the definition and epidemiology, as well as a proposed diagnostic algorithm and treatment options, are presented. Ongoing research is desirable to establish clear management strategies that are based on the pathophysiologic mechanisms responsible for the escalation of the syndrome's symptoms to a fraction of the population of pregnant women.

The adult human pubic symphysis: a systematic review

The pubic symphysis is a unique joint consisting of a fibrocartilaginous disc sandwiched between the articular surfaces of the pubic bones. It resists tensile, shearing and compressive forces and is capable of a small amount of movement under physiological conditions in most adults (up to 2 mm shift and 1° rotation). During pregnancy, circulating hormones such as relaxin induce resorption of the symphyseal margins and structural changes in the fibrocartilaginous disc, increasing symphyseal width and mobility. This systematic review of the English, German and French literature focuses on the normal anatomy of the adult human pubic symphysis. Although scientific studies of the joint have yielded useful descriptive data, comparison of results is hampered by imprecise methodology and/or poorly controlled studies. Several aspects of the anatomy of the pubic symphysis remain unknown or unclear: the precise attachments of surrounding ligaments and muscles; the arrangement of connective tissue fibres within the interpubic disc and the origin, structure and function of its associated interpubic cleft; the biomechanical consequences of sexual dimorphism; potential ethnic variations in morphology; and its precise innervation and blood supply. These deficiencies hinder our understanding of the normal form and function of the joint, which is particularly relevant when attempting to understand the mechanisms underlying pregnancy-related pubic symphyseal pain, a neglected and relatively common cause of pubic pain. A better understanding of the normal anatomy of the human pubic symphysis should improve our understanding of such problems and contribute to better treatments for patients suffering from symphyseal pain and dysfunction.

Pelvic girdle pain in pregnancy: the impact of parity

OBJECTIVE

The purpose of this study was to estimate the association of parity with pelvic girdle syndrome (PGS; pain in anterior and bilateral posterior pelvis).

STUDY DESIGN

We included 75,939 pregnant women in the Norwegian Mother and Child Cohort Study. Data were obtained by self-administered questionnaires.

RESULTS

By pregnancy week 30, 15% of the women had developed PGS. Among first-time mothers, 11% of the women reported PGS, compared with 18% of the women with 1 previous delivery and 21% of women with 2 previous deliveries. The odds ratios for PGS of having had 1 or 2 previous deliveries were 1.9 (95% confidence interval [CI], 1.9-2.0) and 2.4 (95% CI, 2.3-2.6), respectively, after adjustment for other study factors. For PGS with severe pain, the corresponding odds ratios were 2.6 (95% CI, 2.3-2.9) and 3.8 (95% CI, 3.3-4.3).

CONCLUSION

The risk of the development of PGS increased with number of previous deliveries, which suggests that parity-related factors play a causal role.

European guidelines for the diagnosis and treatment of pelvic girdle pain

A guideline on pelvic girdle pain (PGP) was developed by "Working Group 4" within the framework of the COST ACTION B13 "Low back pain: guidelines for its management", issued by the European Commission, Research Directorate-General, Department of Policy, Coordination and Strategy. To ensure an evidence-based approach, three subgroups were formed to explore: (a) basic information, (b) diagnostics and epidemiology, and (c) therapeutical interventions. The progress of the subgroups was discussed at each meeting and the final report is based on group consensus. A grading system was used to denote the strength of the evidence, based on the AHCPR Guidelines (1994) and levels of evidence recommended in the method guidelines of the Cochrane Back Review group. It is concluded that PGP is a specific form of low back pain (LBP) that can occur separately or in conjunction with LBP. PGP generally arises in relation to pregnancy, trauma, arthritis and/or osteoarthritis. Uniform definitions are proposed for PGP as well as for joint stability. The point prevalence of pregnant women suffering from PGP is about 20%. Risk factors for developing PGP during pregnancy are most probably a history of previous LBP, and previous trauma to the pelvis. There is agreement that non risk factors are: contraceptive pills, time interval since last pregnancy, height, weight, smoking, and most probably age. PGP can be diagnosed by pain provocation tests (P4/thigh thrust, Patrick's Faber, Gaenslen's test, and modified Trendelenburg's test) and pain palpation tests (long dorsal ligament test and palpation of the symphysis). As a functional test, the active straight leg raise (ASLR) test is recommended. Mobility (palpation) tests, X-rays, CT, scintigraphy, diagnostic injections and diagnostic external pelvic fixation are not recommended. MRI may be used to exclude ankylosing spondylitis and in the case of positive red flags. The recommended treatment includes adequate information and reassurance of the patient, individualized exercises for pregnant women and an individualized multifactorial treatment program for other patients. We recommend medication (excluding pregnant women), if necessary, for pain relief. Recommendations are made for future research on PGP.

Variation of the obturator foramen and pubic arch of the female bony pelvis

OBJECTIVE

The purpose of this study was to determine dimensions of the obturator foramen and pubic arch of the female pelvis and to assess for variability.

STUDY DESIGN

Ninety-six female pelvises were selected from the Cleveland Natural History Museum. The obturator foramen area, pubic arch angle, pubic ramus, pubic symphysis, and anterior urogenital triangle area were measured. Linear regression was used to evaluate independent associations.

RESULTS

There was considerable variability of the bony architecture. The mean obturator foramen area was 12.2 +/- 2.1 cm(2) (range, 7.38-18.22 cm(2)). After controlling for height, the pubic ramus width, pubic symphysis length, and interobturator foramina distance were significantly greater in European American women compared with African American women. Obturator foramen area increased with increasing height (P = .0008) but was not associated with race.

CONCLUSION

There is considerable variability in the bony architecture of the obturator foramen and pubic arch of the female pelvis. Race and height may account for some of these variabilities.

Relationship between cortical bone formation on mandibular condyles and alternation of the magnetic resonance signals characteristic of growth

INTRODUCTION

The purpose of this study was to elucidate the significance of double contour-like structures (DCLS) relative to the maturity of mandibular condyles and the possible constituents of DCLS. We evaluated the relationship between the alternation of DCLS and the ossification on the top of mandibular condyles.

METHODS

In 36 subjects, aged 9 to14 years at the first examination, magnetic resonance imaging characteristics of the mandibular condyles were obtained from fast spin echo intermediate-weighted images and T2-weighted images; 2 or 3 years later, magnetic resonance images were again obtained from 23 of the same 36 subjects.

RESULTS

A significant relationship was found between the absence of DCLS and the continuity of void-signal lines on the tops of the mandibular condyles. DCLS disappeared, and the void-signal lines on the tops of the mandibular condyles became continuous as the children grew. The top of DCLS was seen as a hypersignal on T2-weighted images.

CONCLUSIONS

Alternations of DCLS might be a useful criterion for evaluating the maturity of mandibular condyles in children. Possible constituents of DCLS might be hypervascular loose fibrous tissue and a proliferation of cartilage accompanied by active ossification on the tops of the mandibular condyles.

Detection and significance of the characteristic magnetic resonance signals of mandibular condyles in children

OBJECTIVE

We sought to determine the magnetic resonance imaging (MRI) characteristics of mandibular condyles in still-growing children. In addition, we also evaluated the significance of the double-contour-like structure and the conversion from red to yellow marrow characteristic of this age.

METHODS

The MRI characteristics of mandibular condyles were determined by means of fast spin-echo intermediate-weighted images in subjects 9 to 14 years old. In 1 subject who developed temporomandibular joint-related clinical symptoms 1 year later, MRI was re-performed at that time.

RESULTS

With the use of MRI, a total of 17 double-contour-like structures were detected in 42 temporomandibular joints of 9- to 14-year-olds, but neither 50 healthy joints of youths nor adults. In terms of bone marrow signal changes, the turning point was found to be 11 years old. In 1 subject, the double-contour-like structures were not visible on the MR images obtained 1 year after the first examination.

CONCLUSION

The double-contour-like structure and the periods of conversion from red to yellow marrow may be able to be used as part of the criteria for the staging of mandibular condyle development in children.