Bone densitometry in the diagnosis of vertebral fractures in children: accuracy of vertebral fracture assessment

Activity-restriction only as treatment yields positive outcomes in pediatric spinal compression fractures: a prospective study of 47 patients at medium-term follow-up

BACKGROUND AND PURPOSE

We aimed to evaluate the clinical outcomes, radiographic results, and health-related quality of life in pediatric AO type A1 spinal compression fractures treated with activity-restriction only.

PATIENTS AND METHODS

All children between 2014 and 2020 with an AO type A1 spinal compression fracture treated with activity-restriction only identified from an institutional fracture registry were invited to a prospective outcomes study. Clinical findings and spinal radiographs were assessed at median 3 years, interquartile range (IQR) 1-4 follow-up from injury. Oswestry Disability Index, Pediatric Quality of Life Inventory Generic Core Scale (PedsQL), and PedsQL Pediatric Pain Questionnaire were compared with reference values. 63 children were identified, of whom 47 agreed to participate. 8 were polytrauma patients.

RESULTS

Age at injury was median 11 (IQR 9-14) years. The number of injured vertebrae was median 2 (IQR 1-3). 82% (94 of 115) were thoracic vertebrae fractures and 70% (33 of 47) of the patients had thoracic vertebrae fractures only. At follow-up all but 2 fractures showed radiographic remodeling. There was no difference from the published reference values in the patient-reported outcome measures. A lower PedsQL physical functioning score was associated with higher patient-reported pain (P = 0.03). At follow-up 12 patients had hyperkyphosis (median difference from the reference values 4°, IQR 3-6, 95% confidence interval [CI] 3-6) and 5 hypolordosis (median difference from reference 8°, IQR 4-11, CI 4-14). None of the patients had surgery for deformity during follow-up.

CONCLUSION

Clinical, radiographic, and health-related quality of life outcomes were good after activity-restriction treatment in pediatric A1 spinal compression fractures.

Observer Agreement of Vertebral Fracture Grading Using Dual Energy Absorptiometry Vertebral Fracture Assessment in Duchenne Muscular Dystrophy

Routine screening of the spine for vertebral fracture is recommended in the recent international standards of care for boys with Duchenne muscular dystrophy (DMD). Recent international consensus endorses the use of dual energy absorptiometry vertebral fracture assessment for identification of vertebral fractures in children, which could be used instead of spine radiographs. This study aims to evaluate the inter-observer agreement for vertebral fracture classification in boys with DMD, and the impact on clinical management. Dual energy absorptiometry vertebral fracture assessment and morphometric analysis in 39 boys was performed by a reader with no prior experience (R1) and 2 readers with experience (R2 and R3). Inter-observer concordance of vertebral fracture grading comparing R1 with R2 and R3 was substantial (Kappa 0.66, 95% CI 0.56, 0.76). Concordance between R2 and R3 was almost perfect (Kappa 0.93, 95% CI 0.89, 0.97) which did not lead to differences in clinical management. Grading by R1 in comparison to R2 and R3 would have led to change in management of 5/39 boys (13%), according to recent standards of care guidance. Structured education programme on identification of vertebral fractures should be explored to ensure consistency of reporting of this important health outcome measure in DMD.

The Accuracy of Incident Vertebral Fracture Detection in Children Using Targeted Case-Finding Approaches

Vertebral fractures are clinically important sequelae of a wide array of pediatric diseases. In this study, we examined the accuracy of case-finding strategies for detecting incident vertebral fractures (IVF) over 2 years in glucocorticoid-treated children (n = 343) with leukemia, rheumatic disorders, or nephrotic syndrome. Two clinical situations were addressed: the prevalent vertebral fracture (PVF) scenario (when baseline PVF status was known), which assessed the utility of PVF and low lumbar spine bone mineral density (LS BMD; Z-score <-1.4), and the non-PVF scenario (when PVF status was unknown), which evaluated low LS BMD and back pain. LS BMD was measured by dual-energy X-ray absorptiometry, vertebral fractures were quantified on spine radiographs using the modified Genant semiquantitative method, and back pain was assessed by patient report. Forty-four patients (12.8%) had IVF. In the PVF scenario, both low LS BMD and PVF were significant predictors of IVF. Using PVF to determine which patients should have radiographs, 11% would undergo radiography (95% confidence interval [CI] 8-15) with 46% of IVF (95% CI 30-61) detected. Sensitivity would be higher with a strategy of PVF or low LS BMD at baseline (73%; 95% CI 57-85) but would require radiographs in 37% of children (95% CI 32-42). In the non-PVF scenario, the strategy of low LS BMD and back pain produced the highest specificity of any non-PVF model at 87% (95% CI 83-91), the greatest overall accuracy at 82% (95% CI 78-86), and the lowest radiography rate at 17% (95% CI 14-22). Low LS BMD or back pain in the non-PVF scenario produced the highest sensitivity at 82% (95% CI 67-92), but required radiographs in 65% (95% CI 60-70). These results provide guidance for targeting spine radiography in children at risk for IVF. © 2021 American Society for Bone and Mineral Research (ASBMR).

Revisiting the radiographic assessment of osteoporosis-Osteopenia in children 0-2 years of age. A systematic review

BACKGROUND

Imaging for osteoporosis has two major aims, first, to identify the presence of low bone mass (osteopenia), and second, to quantify bone mass using semiquantitative (conventional radiography) or quantitative (densitometry) methods. In young children, densitometry is hampered by the lack of reference values, and high-quality radiographs still play a role although the evaluation of osteopenia as a marker for osteoporosis is subjective and based on personal experience. Medical experts questioned in court over child abuse, often refer to the literature and state that 20-40% loss of bone mass is warranted before osteopenia becomes evident on radiographs. In our systematic review, we aimed at identifying evidence underpinning this statement. A secondary outcome was identifying normal references for cortical thickness of the skeleton in infants born term, < 2 years of age.

METHODS

We undertook systematic searches in Medline, Embase and Svemed+, covering 1946-2020. Unpublished material was searched in Clinical trials and International Clinical Trials Registry Platform (ICTRP). Both relevant subject headings and free text words were used for the following concepts: osteoporosis or osteopenia, radiography, children up to 6 years.

RESULTS

A total 5592 publications were identified, of which none met the inclusion criteria for the primary outcome; the degree of bone loss warranted before osteopenia becomes visible radiographically. As for the secondary outcome, 21 studies were identified. None of the studies was true population based and none covered the pre-defined age range from 0-2 years. However, four studies of which three having a crossectional and one a longitudinal design, included newborns while one study included children 0-2 years.

CONCLUSIONS

Despite an extensive literature search, we did not find any studies supporting the assumption that a 20-40% bone loss is required before osteopenia becomes visible on radiographs. Reference values for cortical thickness were sparse. Further studies addressing this important topic are warranted.

The Accuracy of Prevalent Vertebral Fracture Detection in Children Using Targeted Case-Finding Approaches

Due to concerns about cumulative radiation exposure in the pediatric population, it is not standard practice to perform spine radiographs in most conditions that predispose to vertebral fracture (VF). In this study we examined the accuracy of two clinical predictors, back pain and lumbar spine bone mineral density (LS BMD), to derive four case-finding paradigms for detection of prevalent VF (PVF). Subjects were 400 children at risk for PVF (leukemia 186, rheumatic disorders 135, nephrotic syndrome 79). Back pain was assessed by patient report, LS BMD was measured by dual-energy X-ray absorptiometry, and PVF were quantified on spine radiographs using the modified Genant semiquantitative method. Forty-four patients (11.0%) had PVF. Logistic regression analysis between LS BMD and PVF produced an odds ratio (OR) of 1.9 (95% confidence interval [CI], 1.5 to 2.5) per reduction in Z-score unit, an area under the receiver operating characteristic curve of 0.70 (95% CI, 0.60 to 0.79), and an optimal BMD Z-score cutoff of -1.6. Case identification using either low BMD alone (Z-score < -1.6) or back pain alone gave similar results for sensitivity (55%, 52%, respectively), specificity (78%, 81%, respectively), positive predictive value (PPV; 24%, 25%, respectively), and negative predictive value (NPV; 93%, 93%, respectively). The paradigm using low BMD plus back pain produced lower sensitivity (32%), higher specificity (96%), higher PPV (47%), and similar NPV (92%). The approach using low BMD or back pain had the highest sensitivity (75%), lowest specificity (64%), lowest PPV (20%), and highest NPV (95%). All paradigms had increased sensitivities for higher fracture grades. Our results show that BMD and back pain history can be used to identify children with the highest risk of PVF so that radiography can be used judiciously. The specific paradigm to be applied will depend on the expected PVF rate and the clinical approach to the use of radiography. © 2019 American Society for Bone and Mineral Research.

Expert panel consensus recommendations for diagnosis and treatment of secondary osteoporosis in children

BACKGROUND

Osteoporosis incidence in children is increasing due to the increased survival rate of patients suffering from chronic diseases and the increased use of drugs that can damage bones. Recent changes made to the definition of childhood osteoporosis, along with the lack of guidelines or national consensuses regarding its diagnosis and treatment, have resulted in a wide variability in the approaches used to treat this disease. For these reasons, the Osteogenesis Imperfecta and Childhood Osteoporosis Working Group of the Spanish Society of Pediatric Rheumatology has sounded the need for developing guidelines to standardize clinical practice with regard to this pathology.

METHODS

An expert panel comprised of 6 pediatricians and 5 rheumatologists carried out a qualitative literature review and provided recommendations based on evidence, when that was available, or on their own experience. The level of evidence was determined for each section using the Oxford Centre for Evidence-based Medicine (CEBM) system. A Delphi survey was conducted for those recommendations with an evidence level of IV or V. This survey was sent to all members of the SERPE. All recommendations that had a level of agreement higher or equal to 70% were included.

RESULTS

Fifty-one recommendations, categorized into eight sections, were obtained. Twenty-four of them presented an evidence level 4 or 5, and therefore a Delphi survey was conducted. This was submitted electronically and received a response rate of 40%. All recommendations submitted to the Delphi round obtained a level of agreement of 70% or higher and were therefore accepted.

CONCLUSION

In summary, we present herein guidelines for the prevention, diagnosis and treatment of secondary childhood osteoporosis based on the available evidence and expert clinical experience. We believe it can serve as a useful tool that will contribute to the standardization of clinical practice for this pathology. Prophylactic measures, early diagnosis and a proper therapeutic approach are essential to improving bone health, not only in children and adolescents, but also in the adults they will become in the future.

Bone density in children: what are we measuring?

The measurement of bone density is a frequent request in the assessment of children with concerns about bone health due to chronic disease or recurrent fractures. Dual energy X-ray absorptiometry (DXA) remains the recommended modality and is widely available. However, the interpretation and reporting of results in growing individuals needs to be undertaken by individuals who are familiar with scanning children and the potential pitfalls.

The Utility of DXA Assessment at the Forearm, Proximal Femur, and Lateral Distal Femur, and Vertebral Fracture Assessment in the Pediatric Population: 2019 ISCD Official Position

Dual-energy X-ray absorptiometry (DXA) is widely used in the evaluation of bone fragility in children. Previous recommendations emphasized total body less head and lumbar spine DXA scans for clinical bone health assessment. However, these scan sites may not be possible or optimal for all groups of children with conditions that threaten bone health. The utility of DXA scans of the proximal femur, forearm, and radius were evaluated for adequacy of reference data, precision, ability of predict fracture, and applicability to all, or select groups of children. In addition, the strengths and limitations of vertebral fracture assessment by DXA were evaluated. The new Pediatric Positions provide guidelines on the use of these additional measures in the assessment of skeletal health in children.

Are semi-automated software program designed for adults accurate for the identification of vertebral fractures in children?

Objectives

To assess whether diagnostic accuracy of morphometric vertebral fracture (VF) diagnosis in children can be improved using AVERT™ (a 33-point semi-automated program developed for VF diagnosis in adults) compared with SpineAnalyzer™ (a 6-point program), which has previously been shown to be of insufficient accuracy.

Materials and methods

Lateral spine radiographs (XR) and dual-energy X-ray absorptiometry (DXA) scans of 50 children and young people were analysed by two observers using two different programs (AVERT™ and SpineAnalyzer™). Diagnostic accuracy (sensitivity, specificity, false-negative (FN) and false-positive rates (FP)) was calculated by comparing with a previously established consensus arrived at by three experienced paediatric musculoskeletal radiologists, using a simplified algorithm-based qualitative scoring system. Observer agreement was calculated using Cohen’s kappa.

Results

For XR, overall sensitivity, specificity, FP and FN rates using AVERT™ were 36%, 95%, 5% and 64% respectively and 26%, 98%, 2% and 75% respectively, using SpineAnalyzer™. For DXA, overall sensitivity, specificity, FP and FN rates using AVERT™ were 41%, 91%, 9% and 59% respectively and 31%, 96%, 4% and 69% respectively, using SpineAnalyzer. Reliability (kappa) ranged from 0.34 to 0.37 (95%CI, 0.26–0.46) for AVERT™ and from 0.26 to 0.31 (95%CI, 0.16–0.44) for SpineAnalyzer™. Inter- and intra-observer agreement ranged from 0.41 to 0.47 for AVERT™ and from 0.50 to 0.79 for SpineAnalyzer™.

Conclusion

AVERT™ has slightly higher accuracy but lower observer reliability for the representation of vertebral morphometry in children when compared with SpineAnalyzer™. However, neither software program is satisfactorily reliable for VF diagnosis in children.

Key Points

• SpineAnalyzer™ and AVERT™ have low diagnostic accuracy and observer agreement when compared to three paediatric radiologists’ readings for the diagnosis of vertebral fractures (VF) in children.

• Neither AVERT™ nor SpineAnalyzer™ is satisfactorily reliable for VF diagnosis in children.

• Development of specific paediatric software and normative values (incorporating age-related physiological variation in children) is required.

Diagnosis of osteoporotic vertebral fractures in children

Osteoporosis is a generalised disorder of the skeleton with reduced bone density and abnormal bone architecture. It increases bone fragility and renders the individual susceptible to fractures. Fractures of the vertebrae are common osteoporotic fractures. Vertebral fractures may result in scoliosis or kyphosis and, because they may be clinically silent, it is imperative that vertebral fractures are diagnosed in children accurately and at an early stage, so the necessary medical care can be implemented. Traditionally, diagnosis of osteoporotic vertebral fractures has been from lateral spine radiographs; however, a small number of studies have shown that dual energy x-ray absorptiometry is comparable to radiographs for identifying vertebral fractures in children, while allowing reduced radiation exposure. The diagnosis of vertebral fractures from dual energy x-ray absorptiometry is termed vertebral fracture assessment. Existing scoring systems for vertebral fracture assessment in adults have been assessed for use in children, but there is no standardisation and observer reliability is variable. This literature review suggests the need for a semiautomated tool that (compared to the subjective and semiquantitative methods available) will allow more reliable and precise detection of vertebral fractures in children.

Lumbar spine bone mineral density Z-score discrepancies by dual X-ray absorptiometry do not predict vertebral fractures in children

Dual X-ray absorptiometry (DXA) remains the most common mode of bone mineral density (BMD) evaluation. In adults, presence of a lumbar spine (LS) BMD T-score discrepancy (>1 SD difference between adjacent vertebrae) can indicate a vertebral fracture. In children, however, the clinical significance of such discrepancies is unknown. We conducted a retrospective study to evaluate the association between LS DXA and LS morphology to elucidate the clinical significance of an LS BMD Z-score discrepancy. We identified 360 DXA scans performed between September 2014 and May 2016 in patients 5-18 years of age. DXA scans were cross-referenced against available LS radiographs and vertebral fracture assessment (VFA) within the 6 months preceding or following a DXA scan. After excluding 44 DXA scans because of spinal hardware, incomplete DXA, or repeat scans, 316 DXA scans were included; 81 (25.6%) had either an LS radiograph or a VFA. Twenty-five of 81 patients (30.9%) had >1 SD difference between adjacent vertebrae in LS BMD Z-score. Two of these 25 patients (8%) had a lumbar vertebral fracture documented by a spine radiograph. Of the remaining 56 patients who did not have a discrepancy >1 SD, 6 patients (11%) had a lumbar vertebral fracture. Discrepancies in LS BMD Z-scores were not associated with lumbar vertebral fractures and, in the absence of fractures, likely represented vertebral developmental variants in children whose skeletons are still growing. Therefore, it does not appear justified to recommend further imaging based solely on the results of a DXA scan without clinically meaningful indications.

Osteoporosis in Children with Chronic Illnesses: Diagnosis, Monitoring, and Treatment

PURPOSE OF REVIEW

Osteoporosis is an under-recognized complication of chronic illness in childhood. This review will summarize recent literature addressing the risk factors, evaluation, and treatment for early bone fragility.

RECENT FINDINGS

Criteria for the diagnosis of pediatric osteoporosis include the presence of low trauma vertebral fractures alone or the combination of low bone mineral density and several long bone fractures. Monitoring for bone health may include screening for vertebral fractures that are common but often asymptomatic. Pharmacologic agents should be offered to those with fragility fractures especially when spontaneous recovery is unlikely. Controversies persist about the optimal bisphosphonate agent, dose, and duration. Newer osteoporosis drugs have not yet been adequately tested in pediatrics, though clinical trials are underway. The prevalence of osteoporosis is increased in children with chronic illness. To reduce the frequency of fragility fractures requires increased attention to risk factors, early intervention, and additional research to optimize therapy and potentially prevent their occurrence.

Bone Mineralization and Fracture Risk Assessment in the Pediatric Population

Identifying children most susceptible to clinically significant fragility fractures (low trauma fractures or vertebral compression fractures) or recurrent fractures is an important issue facing general pediatricians and subspecialists alike. Over the last decade, several imaging technologies, including dual-energy X-ray absorptiometry and peripheral quantitative computed tomography, have become useful to identify abnormal bone mineralization in children and in adolescents. This review aimed to summarize the latest literature on the utility of these modalities as they pertain to use in pediatrics. In addition, we review several disease states associated with poor bone health and increased fracture risk in children, and discuss the implications of low bone mineral density in these patients. Finally, we will highlight the gaps in knowledge with regard to pediatric bone health and make recommendations for future areas of research.

The Clinical Utility of Vertebral Fracture Assessment in Predicting Fractures

Vertebral fracture (VF) is the most common type of osteoporotic fracture. VFs are associated with diminished quality of life and high morbidity and mortality. The presence of a VF, especially a recent one, is an important risk factor for developing another fracture. However, most VFs are not clinically recognized. VF assessment by dual-energy X-ray absorptiometry is a convenient, low-cost, low-radiation, reliable method to identify VFs during bone mineral density measurement. The finding of a previously unrecognized VF may change the diagnostic classification, assessment of fracture risk, and treatment strategies. This paper focuses on the utility of VF assessment in clinical practice.

Vertebral fractures assessment in children: Evaluation of DXA imaging versus conventional spine radiography

Vertebral fracture assessment (VFA) by DXA is an accepted tool in adults. However, its use in children has not been assessed. The aim of this study was to evaluate DXA VFA and morphometric analysis (MXA) using a GE Lunar iDXA bone densitometer against spinal radiographic assessment (RA) for the identification of vertebral fractures in children. Spine RA and VFA (T3-L5) were acquired on the same day in 80 children. Forty children considered high risk for fracture by their metabolic bone specialist were referred for spinal RA. Another 40 children were recruited as part of a prospective fracture study and were considered low risk for vertebral fracture. Agreement between RA and VFA was assessed by an expert paediatric radiologist and two paediatricians with expertise in bone pathology. Agreement between RA and MXA was assessed by an expert paediatric radiologist, two clinical scientists and an experienced paediatric radiographer. Vertebrae were ranked as normal, mild, moderate or severe if they had <10%, 11-25%, 26-50% and >50% deformity, respectively. Levels of agreement were calculated using the Cohen kappa score. Evaluating the data from all readable vertebrae, 121 mild, 44 moderate and 16 severe vertebral fractures were identified; with 26, 8, and 5 subjects having at least one mild, moderate or severe fracture, respectively. Depending on rater, 92.8-94.8% of the vertebrae were evaluable by RA. In contrast, 98.4% were evaluable by VFA and only 83.6% were evaluable by MXA. Moderate agreement was found between raters for RA [kappa 0.526-0.592], and VFA [kappa 0.601-0.658] and between RA and VFA [kappa 0.630-0.687]. In contrast, only slight agreement was noted between raters for MXA [kappa 0.361-0.406] and between VFA and MXA [kappa 0.137-0.325]. Agreement substantially improved if the deformities were dichotomised as normal or mild versus moderate or severe [kappa 0.826-0.834]. For the detection of moderate and/or severe fractures the sensitivities & specificities were 81.3% & 99.3%, and 62.5% & 99.2% for VFA and MXA, respectively. This study demonstrates that VFA is as good as RA for detecting moderate and severe vertebral fractures. Given the significant radiation dose saving of VFA compared with RA, VFA is recommended as a diagnostic tool for the assessment of moderate or severe vertebral fracture in children.

Prevalence of Vertebral Fractures in Children with Suspected Osteoporosis

OBJECTIVES

To explore the prevalence and anatomic distribution of vertebral fractures in disease groups investigated for primary and secondary osteoporosis, using vertebral fracture assessment (VFA).

STUDY DESIGN

VFA was performed independently by 2 nonradiologists, in 165 children (77 males, 88 females) as part of their investigation for osteoporosis. Vertebral bodies from T6 to L4 were assessed for vertebral fractures using the Genant scoring system. The common readings for the presence of vertebral fractures were used for evaluating the prevalence and anatomic distribution of vertebral fractures.

RESULTS

The median age of the subjects was 13.4 years (range, 3.6, 18). Of the 165 children, 24 (15%) were being investigated for primary bone disease, and the remainder had a range of chronic diseases known to affect bone health. Vertebral fractures were identified in 38 (23%) children. The distribution of the vertebral fractures was bimodal, with vertebral fractures peaks centered at T9 and L4. Conditions associated with increased odds for vertebral fractures were inflammatory bowel disease (OR, 3.3; 95% CI, 1.4, 8.0; P = .018) and osteogenesis imperfecta (OR, 2.3; 95% CI, 1.04, 5.8; P = .022). Among children with vertebral fractures, those with Duchenne muscular dystrophy (P = .015) and osteogenesis imperfecta (P = .023) demonstrated higher number of vertebral fractures than the other disease groups.

CONCLUSIONS

VFA identified the presence of vertebral fractures, in a bimodal distribution, in both primary bone disease and chronic disease groups. VFA is a practical screening tool for identification of vertebral fractures in children and adolescents at risk of fragility fractures.

Bone Densitometry in Children and Adolescents

Concerns about bone health and potential fragility in children and adolescents have led to a high interest in bone densitometry. Pediatric patients with genetic and acquired chronic diseases, immobility, and inadequate nutrition may fail to achieve expected gains in bone size, mass, and strength, leaving them vulnerable to fracture. In older adults, bone densitometry has been shown to predict fracture risk and reflect response to therapy. The role of densitometry in the management of children at risk of bone fragility is less clear. This clinical report summarizes current knowledge about bone densitometry in the pediatric population, including indications for its use, interpretation of results, and risks and costs. The report emphasizes updated consensus statements generated at the 2013 Pediatric Position Development Conference of the International Society of Clinical Densitometry by an international panel of bone experts. Some of these recommendations are evidence-based, whereas others reflect expert opinion, because data are sparse on many topics. The statements from this and other expert panels provide general guidance to the pediatrician, but decisions about ordering and interpreting bone densitometry still require clinical judgment. The interpretation of bone densitometry results in children differs from that in older adults. The terms "osteopenia" and "osteoporosis" based on bone densitometry findings alone should not be used in younger patients; instead, bone mineral content or density that falls >2 SDs below expected is labeled "low for age." Pediatric osteoporosis is defined by the Pediatric Position Development Conference by using 1 of the following criteria: ≥1 vertebral fractures occurring in the absence of local disease or high-energy trauma (without or with densitometry measurements) or low bone density for age and a significant fracture history (defined as ≥2 long bone fractures before 10 years of age or ≥3 long bone fractures before 19 years of age). Ongoing research will help define the indications and best methods for assessing bone strength in children and the clinical factors that contribute to fracture risk. The Pediatric Endocrine Society affirms the educational value of this publication.

Diagnostic accuracy of DXA compared to conventional spine radiographs for the detection of vertebral fractures in children

OBJECTIVES

In children, radiography is performed to diagnose vertebral fractures and dual energy x-ray absorptiometry (DXA) to assess bone density. In adults, DXA assesses both. We aimed to establish whether DXA can replace spine radiographs in assessment of paediatric vertebral fractures.

METHODS

Prospectively, lateral spine radiographs and lateral spine DXA of 250 children performed on the same day were independently scored by three radiologists using the simplified algorithm-based qualitative technique and blinded to results of the other modality. Consensus radiograph read and second read of 100 random images were performed. Diagnostic accuracy, inter/intraobserver and intermodality agreements, patient/carer experience and radiation dose were assessed.

RESULTS

Average sensitivity and specificity (95 % confidence interval) in diagnosing one or more vertebral fractures requiring treatment was 70 % (58-82 %) and 97 % (94-100 %) respectively for DXA and 74 % (55-93 %) and 96 % (95-98 %) for radiographs. Fleiss' kappa for interobserver and average kappa for intraobserver reliability were 0.371 and 0.631 respectively for DXA and 0.418 and 0.621 for radiographs. Average effective dose was 41.9 μSv for DXA and 232.7 μSv for radiographs. Image quality was similar.

CONCLUSION

Given comparable image quality and non-inferior diagnostic accuracy, lateral spine DXA should replace conventional radiographs for assessment of vertebral fractures in children.

KEY POINTS

• Vertebral fracture diagnostic accuracy of lateral spine DXA is non-inferior to radiographs. • The rate of unreadable vertebrae for DXA is lower than for radiographs. • Effective dose of DXA is significantly lower than radiographs. • Children prefer DXA to radiographs. • Given the above, DXA should replace radiographs for paediatric vertebral fracture assessment.

The management of osteoporosis in children

This article reviews the manifestations and risk factors associated with osteoporosis in childhood, the definition of osteoporosis and recommendations for monitoring and prevention. As well, this article discusses when a child should be considered a candidate for osteoporosis therapy, which agents should be prescribed, duration of therapy and side effects. There has been significant progress in our understanding of risk factors and the natural history of osteoporosis in children over the past number of years. This knowledge has fostered the development of logical approaches to the diagnosis, monitoring, and optimal timing of osteoporosis intervention in this setting. Current management strategies are predicated upon monitoring at-risk children to identify and then treat earlier rather than later signs of osteoporosis in those with limited potential for spontaneous recovery. On the other hand, trials addressing the prevention of the first-ever fracture are still needed for children who have both a high likelihood of developing fractures and less potential for recovery. This review focuses on the evidence that shapes the current approach to diagnosis, monitoring, and treatment of osteoporosis in childhood, with emphasis on the key pediatric-specific biological principles that are pivotal to the overall approach and on the main questions with which clinicians struggle on a daily basis. The scope of this article is to review the manifestations of and risk factors for primary and secondary osteoporosis in children, to discuss the definition of pediatric osteoporosis, and to summarize recommendations for monitoring and prevention of bone fragility. As well, this article reviews when a child is a candidate for osteoporosis therapy, which agents and doses should be prescribed, the duration of therapy, how the response to therapy is adjudicated, and the short- and long-term side effects. With this information, the bone health clinician will be poised to diagnose osteoporosis in children and to identify when children need osteoporosis therapy and the clinical outcomes that gauge efficacy and safety of treatment.

Diagnosis of vertebral fractures in children: is a simplified algorithm-based qualitative technique reliable?

BACKGROUND

Identification of osteoporotic vertebral fractures allows treatment opportunity reducing future risk. There is no agreed standardised method for diagnosing paediatric vertebral fractures.

OBJECTIVE

To evaluate the precision of a modified adult algorithm-based qualitative (ABQ) technique, applicable to children with primary or secondary osteoporosis.

MATERIALS AND METHODS

Three radiologists independently assessed lateral spine radiographs of 50 children with suspected reduction in bone mineral density using a modified ABQ scoring system and following simplification to include only clinically relevant parameters, a simplified ABQ score. A final consensus of all observers using simplified ABQ was performed as a reference standard for fracture characterisation. Kappa was calculated for interobserver agreement of the components of both scoring systems and intraobserver agreement of simplified ABQ based on a second read of 29 randomly selected images.

RESULTS

Interobserver Kappa for modified ABQ scoring for fracture detection, severity and shape ranged from 0.34 to 0.49 Kappa for abnormal endplate and position assessment was 0.27 to 0.38. Inter- and intraobserver Kappa for simplified ABQ scoring for fracture detection and grade ranged from 0.37 to 0.46 and 0.45 to 0.56, respectively. Inter- and intraobserver Kappa for affected endplate ranged from 0.31 to 0.41 and 0.45 to 0.51, respectively. Subjectively, observers' felt simplified ABQ was easier and less time-consuming.

CONCLUSION

Observer reliability of modified and simplified ABQ was similar, with slight to moderate agreement for fracture detection and grade/severity. Due to subjective preference for simplified ABQ, we suggest its use as a semi-objective measure of diagnosing paediatric vertebral fractures.

A critical appraisal of vertebral fracture assessment in paediatrics

PURPOSE

There is a need to improve our understanding of the clinical utility of vertebral fracture assessment (VFA) in paediatrics and this requires a thorough evaluation of its readability, reproducibility, and accuracy for identifying VF.

METHODS

VFA was performed independently by two observers, in 165 children and adolescents with a median age of 13.4 years (range, 3.6, 18). In 20 of these subjects, VFA was compared to lateral vertebral morphometry assessment on lateral spine X-ray (LVM).

RESULTS

1528 (84%) of the vertebrae were adequately visualised by both observers for VFA. Interobserver agreement in vertebral readability was 94% (kappa, 0.73 [95% CI, 0.68, 0.73]). 93% of the non-readable vertebrae were located between T6 and T9. Interobserver agreement per-vertebra for the presence of VF was 99% (kappa, 0.85 [95% CI, 0.79, 0.91]). Interobserver agreement per-subject was 91% (kappa, 0.78 [95% CI, 0.66, 0.87]). Per-vertebra agreement between LVM and VFA was 95% (kappa 0.79 [95% CI, 0.62, 0.92]) and per-subject agreement was 95% (kappa, 0.88 [95% CI, 0.58, 1.0]). Accepting LVM as the gold standard, VFA had a positive predictive value (PPV) of 90% and a negative predictive value (NPV) of 95% in per-vertebra analysis and a PPV of 100% and NPV of 93% in per-subject analysis.

CONCLUSION

VFA reaches an excellent level of agreement between observers and a high level of accuracy in identifying VF in a paediatric population. The readability of vertebrae at the mid thoracic region is suboptimal and interpretation at this level should be exercised with caution.

ENDOCRINOLOGY AND ADOLESCENCE: Osteoporosis in children: diagnosis and management

Osteoporosis in children can be primary or secondary due to chronic disease. Awareness among paediatricians is vital to identify patients at risk of developing osteoporosis. Previous fractures and backaches are clinical predictors, and low cortical thickness and low bone density are radiological predictors of fractures. Osteogenesis Imperfecta (OI) is a rare disease and should be managed in tertiary paediatric units with the necessary multidisciplinary expertise. Modern OI management focuses on functional outcomes rather than just improving bone mineral density. While therapy for OI has improved tremendously over the last few decades, this chronic genetic condition has some unpreventable, poorly treatable and disabling complications. In children at risk of secondary osteoporosis, a high degree of suspicion needs to be exercised. In affected children, further weakening of bone should be avoided by minimising exposure to osteotoxic medication and optimising nutrition including calcium and vitamin D. Early intervention is paramount. However, it is important to identify patient groups in whom spontaneous vertebral reshaping and resolution of symptoms occur to avoid unnecessary treatment. Bisphosphonate therapy remains the pharmacological treatment of choice in both primary and secondary osteoporosis in children, despite limited evidence for its use in the latter. The duration and intensity of treatment remain a concern for long-term safety. Various new potent antiresorptive agents are being studied, but more urgently required are studies using anabolic medications that stimulate bone formation. More research is required to bridge the gaps in the evidence for management of paediatric osteoporosis.

Reliability of vertebral fractures assessment (VFA) in children with osteogenesis imperfecta

The aim of this study is to evaluate the diagnostic accuracy of vertebral fractures assessment (VFA) in comparison with conventional radiography in identifying vertebral fractures in children and adolescents affected by OI. On 58 patients (33 males, 25 females; age range 1-18 years; 41 children and 17 adolescents) with osteogenesis imperfecta (OI type I, n = 44, OI type III, n = 4; OI type IV, n = 10), lateral spine images by radiographs and by dual-energy X-ray absorptiometry (DXA) were acquired. For vertebral fracture diagnosis, plain radiographs were used as "gold standard" and VFA and morphometric X-ray absorptiometry (MXA) were performed. The visualized vertebrae were 738 (97.9%) by radiographs and 685 (90.9%) by DXA of a total of 754 vertebrae from T4 to L4. VFA and MXA identified, respectively, 129 (74%) and 116 (66%) of the 175 vertebral fractures detected by radiographs. Radiographs identified 36 patients with vertebral fractures, VFA 35 and MXA 41 (6 false positives). On a per vertebra basis, radiographs and VFA had elevated agreement (93.9%; k score 0.81, 95% CI 0.76-0.86), that resulted slightly lower for MXA (90.6%; k score 0.72, 95% CI 0.65-0.78). VFA and MXA demonstrated high sensitivity (95.6 and 94.1 %, respectively) while specificity was 100% for VFA and 90.6% for MXA on a per patient basis; the agreement was excellent for VFA (98.3%; k score 0.96, 95% CI 0.89-1.03) and good for MXA (87.9%; k score 0.73, 95% CI 0.55-0.91). The diagnostic performance parameters resulted better for VFA (sensitivity 95.6%; specificity 100%; PPV 100%; NPV 97.2%), than for MXA (sensitivity 94.1%; specificity 85.4%; PPV 72.7%; NPV 97.2%). The results of our study demonstrate the reliability of VFA for diagnosis of vertebral fractures in children with OI suggesting its use as a more safe and practical alternative to conventional radiography.

Diagnosis and treatment of pediatric osteoporosis

PURPOSE OF REVIEW

Progress toward identifying and treating disorders of bone fragility in pediatric patients has been considerable in recent years. This article will summarize several key advances in the management of osteoporosis in children and adolescents.

RECENT FINDINGS

Recommendations from the 2013 pediatric Position Development Conference provide expert guidance for evaluating bone health in younger patients. The diagnosis of pediatric osteoporosis can be made in a child with low-trauma vertebral fractures or a combination of low bone mass and long bone fractures. Management of bone fragility includes optimizing nutrition, activity, and treatment of the underlying disease. Pharmacologic agents can be considered if these measures fail to prevent further bone loss or fractures. Although the efficacy and safety of several intravenous and oral bisphosphonates have been examined, there is still no consensus on the optimal drug, dose, or duration of treatment. Observational studies of children with secondary osteoporosis provide insight into risk factors for fracture or the potential for recovery.

SUMMARY

Despite advances in the diagnosis and treatment of pediatric osteoporosis, more research is needed. Randomized controlled trials of pharmacologic agents should be defined to target those identified at the highest risk by observational studies.

VIDEO ABSTRACT

http://links.lww.com/COE/A9

Bone densitometry in children and adolescents

PURPOSE OF REVIEW

Abnormalities in bone health are increasingly recognized in the pediatric population. Although the methodologies for assessing bone mineral density were originally developed for adults, great strides have been made in recent years, improving their applicability to children. Understanding these technologies, their interpretation, utility, and limitations is critical when assessing a child or adolescent with a suspected abnormality in bone mineral density.

RECENT FINDINGS

Improved normative databases that address some of the confounding variables in the growing and maturing child have solidified dual-energy X-ray absorptiometry as the preferred method for the assessment of bone mineral density in children. Consensus statements by expert panels now provide specific guidance to clinicians seeking to evaluate children with fractures or at risk for fractures. Although still primarily a research tool, continued development of quantitative computed tomography applications in pediatrics suggests there may be a complementary role for clinical use in the future.

SUMMARY

In the child or adolescent with a significant fracture history or a potential for fractures because of an underlying cause, clinicians now have guidelines and normative data to better focus their evaluation. Likewise, researchers can use this information to improve clinical trial design and interpretation of results.

Observer agreement in pediatric semiquantitative vertebral fracture diagnosis

BACKGROUND

The Genant semiquantitative (GSQ) method has been a standard procedure for diagnosis of vertebral fractures in adults but has only recently been shown to be of clinical utility in children. Observer agreement using the GSQ method in this age group has not been described.

OBJECTIVE

To evaluate observer agreement on vertebral readability and vertebral fracture diagnosis using the GSQ method in pediatric vertebral morphometry.

MATERIALS AND METHODS

Spine radiographs of 186 children with acute lymphoblastic leukemia were evaluated independently by three radiologists using the same GSQ methodology as in adults. A subset of 100 radiographs was evaluated on two occasions.

RESULTS

An average of 4.7% of vertebrae were unreadable for the three radiologists. Intraobserver Cohen's kappa (κ) on readability ranged from 0.434 to 0.648 at the vertebral level and from 0.416 to 0.611 at the patient level, while interobserver κ for readability had a range of 0.330 to 0.504 at the vertebral level and 0.295 to 0.467 at the patient level. Intraobserver κ for the presence of vertebral fracture had a range of 0.529 to 0.726 at the vertebral level and was 0.528 to 0.767 at the patient level. Interobserver κ for fracture at the vertebral level ranged from 0.455 to 0.548 and from 0.433 to 0.486 at the patient level.

CONCLUSION

Most κ values for both intra- and interobserver agreement in applying the GSQ method to pediatric spine radiographs were in the moderate to substantial range, comparable to the performance of the technique in adult studies. The GSQ method should be considered for use in pediatric research and clinical practice.

Effect of body composition on bone mineral density in Moroccan patients with juvenile idiopathic arthritis

Introduction

The link between bone mass and body composition is widely recognized, but only few works were selectively performed on subjects with juvenile idiopathic arthritis. The aim of our study was to investigate the effect of body composition on bone mineral density (BMD) in Moroccan patients with juvenile idiopathic arthritis.

Methods

Thirty three children with juvenile idiopathic arthritis (JIA) were included in a cross-sectional study. The diagnosis of JIA was made according to the criteria of the International League of Association of Rheumatology (ILAR). Body mass index (BMI) was calculated from the ratio of weight/height²(kg/m²). Pubertal status was determined according to the Tanner criteria. Bone status, body composition and bone mineral content (BMC) were analyzed by using dual-energy X-ray absorptiometry (DXA). BMD was assessed at the lumbar spine (L1-L4) and at total body in (g/cm²). Total body fat tissue mass (FTM) and lean tissue mass (LTM) were also analyzed by DXA and expressed in kilograms. In children, low BMD was defined as a Z-score less than -2 and osteoporosis was defined as a Z-score less than -2 with a fracture history.

Results

A cross-sectional study was conducted in 33 Moroccan patients with JIA aged between 4 and 16 years, Fat mass was not related to bone density; in contrast, BMD was positively associated to LTM in total body(r = =0.41, p= 0.04) but not in lumbar spine (r = 0.29, p= 0.17). There exist significant correlation between BMC and BMD in total body (r = 0.51, p = 0.01).

Conclusion

This study suggests that the LTM is a determining factor of the BMD during adolescence. Other studies with a broader sample would be useful to confirm this relation.

Vertebral fracture assessment in adolescents and young women with anorexia nervosa: a case series

Rates of vertebral fracture (VF) in young women with anorexia nervosa (AN) are not well understood. We sought to determine the rates of asymptomatic VF in patients suffering from AN, hypothesizing that VF rates would be higher in subjects with low bone mineral density (BMD) Z-scores. We recruited young women with AN (n = 80) for participation in a longitudinal trial. Dual-energy X-ray absorptiometry images of the lateral thoracic and lumbar spines were obtained for VF assessment at 0, 6, 12, and 18 mo. Thirteen subjects (16%) had a low spinal BMD at baseline (BMD Z-score ≤-2 standard deviation). Using the Genant semiquantitative technique, 2 of 80 subjects at baseline (2.5%) had evidence of a single Genant grade 1 deformity. One subject had a Genant grade 2 deformity. Over the 18-mo trial, 10 incident VFs occurred in 9 subjects (12.5%). Using quantitative techniques, only 2 subjects had a more than 15% loss in vertebral height. Neither anthropometric data nor markers of disease severity were associated with fracture. In conclusion, ill young women with AN were at low risk for asymptomatic VF in our cohort. VFs were not predicted by duration of illness, severity of malnutrition, or traditional measures of areal BMD at the lumbar spine.

Diagnosis of Osteoporosis in Children and Adolescents

Osteoporosis is traditionally regarded as a disease of elderly women. However, this bone disorder occurs in patients of both sexes and of all ages and is also increasingly recognised in the paediatric setting. In particular, patients, including young children, with other chronic diseases are at risk of developing bone fragility. There are also several forms of hereditary osteoporosis, which should be identified at an early stage to ensure adequate treatment. The diagnosis of osteoporosis in children is challenging, since their bone mineral density (BMD) is affected by growth and pubertal development. In addition to low BMD, a child must also exhibit a significant proneness to fractures before the osteoporosis diagnosis can be made. Through early diagnosis and treatment for paediatric bone fragility, we can also ameliorate bone health in adulthood. In this article we review the aetiology, known risk factors and the diagnostic criteria of osteoporosis in the young.

Advances in bone imaging for osteoporosis

The diagnosis and management of osteoporosis have been improved by the development of new quantitative methods of skeletal assessment and by the availability of an increasing number of therapeutic options, respectively. A number of imaging methods exist and all have advantages and disadvantages. Dual-energy X-ray absorptiometry (DXA) is the most widely available and commonly utilized method for clinical diagnosis of osteoporosis and will remain so for the foreseeable future. The WHO 10-year fracture risk assessment tool (FRAX(®)) will improve clinical use of DXA and the cost-effectiveness of therapeutic intervention. Improved reporting of radiographic features that suggest osteoporosis and the presence of vertebral fracture, which are powerful predictors of future fractures, could increase the frequency of appropriate DXA referrals. Quantitative CT remains predominantly a research tool, but has advantages over DXA--allowing measurement of volumetric density, separate measures of cortical and trabecular bone density, and evaluation of bone shape and size. High resolution imaging, using both CT and MRI, has been introduced to measure trabecular and cortical bone microstructure. Although these methods provide detailed insights into the effects of disease and therapies on bone, they are technically challenging and not widely available, so they are unlikely to be used in clinical practice.

Impaired bone health in inflammatory bowel disease: a case-control study in 80 pediatric patients

Previous studies have indicated that children with inflammatory bowel disease (IBD) may not achieve optimal bone mass. We evaluated the skeletal characteristics in children and adolescents with IBD. This cross-sectional cohort study comprised 80 IBD patients (median age 14.9 years, range 5-20) with a median disease duration of 3.4 years; 51 had ulcerative colitis, 26 Crohn disease, and 3 unspecified colitis. Eighty age- and gender-matched healthy subjects served as controls. Areal bone mineral density (aBMD), body composition, and vertebral fractures (VFs) were assessed by DXA. Bone age (BA) was determined for IBD patients. Findings were correlated with disease- and treatment-related parameters and biochemistry. IBD patients had lower BA-adjusted lumbar spine and whole-body aBMD (p < 0.001 for both) and whole-body BMC adjusted for height (p = 0.02) than controls. Lean mass and fat mass Z scores did not differ between the groups, but IBD patients had lower whole-body BMC relative to muscle mass (p = 0.006). Despite vitamin D supplementation in 48 %, vitamin D deficiency was common. In IBD cumulative weight-adjusted prednisolone dose >150 mg/kg for the preceding 3 years increased the risk for low whole-body aBMD (OR = 5.5, 95 % CI 1.3-23.3, p = 0.02). VFs were found in 11 % of patients and in 3 % of controls (p = 0.02). IBD in childhood was associated with low aBMD and reduced bone mass accrual relative to muscle mass; the risk for subclinical VFs may be increased. These observations warrant careful follow-up and active preventive measures.

The thoracic and lumbar spine in severe juvenile idiopathic arthritis: magnetic resonance imaging analysis in 50 children

OBJECTIVE

To determine the prevalence of vertebral fractures as a complication of juvenile idiopathic arthritis (JIA).

STUDY DESIGN

This cross-sectional study evaluated the prevalence and characteristics of spinal abnormalities in 50 children (aged 7.0-18.7 years) with treatment-resistant JIA by magnetic resonance imaging. Vertebral deformities, endplate irregularities, intervertebral disc involvement, spinal canal, neural foramina, and back muscles were analyzed and correlated with clinical characteristics and bone mineral density.

RESULTS

Magnetic resonance imaging revealed various abnormalities in 31 patients (62%). Vertebral compression was seen in 28%, disc degeneration in 46%, protrusions in 14%, prolapses in 4%, endplate changes in 26%, and anterior vertebral corner lesions in 16%. Two patients (4%) had mild spinal canal narrowing without medullar involvement; none had neural root compression. Six patients (12%) had mild back muscle atrophy. No correlation was observed between spinal fractures or other vertebral changes and disease activity or duration, pain or bone mineral density; patients with spinal fractures tended to have a higher recent glucocorticoid exposure (P=.086).

CONCLUSION

Children with severe JIA have a high prevalence of compression fractures and other vertebral, endplate, and disc abnormalities in the thoracic and lumbar spine.

Approach to the child with fractures

Evaluation of the child with fractures is challenging, as no clear guidelines exist to distinguish traumatic from pathological fractures. Although most fractures in childhood are benign, recurrent fractures may be associated with a wide variety of primary skeletal diseases as well as secondary causes, necessitating a careful history and physical exam to guide the evaluation. There is no "gold standard" for the evaluation and treatment of children with fractures and low bone mineral density (BMD); therefore, the diagnosis of osteoporosis in a pediatric patient should be made using a combination of clinical and radiographic features. Interpretation of bone densitometry in growing patients presents a unique set of challenges because areal BMD measured by dual-energy x-ray absorptiometry depends on multiple dynamic variables. Interpretation of pediatric dual-energy x-ray absorptiometry should be based on Z-scores (sd scores compared to age, sex, and ethnicity-matched controls), using normative databases specific to the brand of densitometer and the patient population. Given the skeleton's ability to recover from low BMD through modeling and remodeling, optimizing management of underlying conditions leading to bone fragility is the initial step. Conservative measures including calcium and vitamin D supplementation and weight-bearing physical activity are important interventions that should not be overlooked. The use of bisphosphonates in children and adolescents is controversial due to lack of long-term efficacy and safety data and should be limited to clinical trials and compassionate therapy in children with significantly compromised quality of life. Close monitoring is required, and further study is necessary to assess their long-term safety and efficacy in children.

Clinical report—bone densitometry in children and adolescents

Concern for bone fragility in children and adolescents has led to increased interest in bone densitometry. Pediatric patients with genetic and acquired chronic diseases, immobility, and inadequate nutrition may fail to achieve the expected gains in bone size, mass, and strength, which leaves them vulnerable to fracture. In older adults, bone densitometry has been shown to predict fracture risk and reflect response to therapy. The role of densitometry in the management of children at risk of bone fragility is less certain. This clinical report summarizes the current knowledge about bone densitometry in the pediatric population, including indications for its use, interpretation of results, and its risks and costs. This report emphasizes consensus statements generated at the 2007 Pediatric Position Development Conference of the International Society of Clinical Densitometry by an international panel of bone experts. Some of these recommendations are evidence-based, and others reflect expert opinion, because the available data are inadequate. The statements from this and other expert panels have provided general guidance to the pediatrician, but decisions about ordering and interpreting bone densitometry still require clinical judgment. Ongoing studies will help to better define the indications and best methods for assessing bone strength in children and the clinical factors that contribute to fracture risk.

Measurement of bone density in the pediatric population

PURPOSE OF REVIEW

The purpose of this review is to provide a comprehensive synopsis of pediatric bone density. Osteoporosis of the adult is a well established clinical problem, and algorithms to diagnose and treat this disease are recognized throughout the medical community. Osteoporosis or 'low bone mass' in pediatrics, on the other hand, is a rather new and evolving area, with certain unique diagnostic and clinical challenges.

RECENT FINDINGS

Recent findings in the literature include benefits and limitations of pediatric bone densitometry techniques, proper interpretation of the results of these various techniques, efforts to establish standards and guidelines for diagnosing low bone mass in children and adolescents, optimization of bone growth and mineral accrual for life, pediatric bone mineral density and fracture risk prediction, as well as a clearer awareness of bone fragility in children.

SUMMARY

Throughout the last decade, great strides have been made in our understanding of pediatric metabolic bone disease. These will be the focus of this review.