SF 1 - Assessing age, based on bone maturation: scientific and ethical aspects
1. To become familiar with current indications for bone age assessment.
2. To learn about the methods' precision and accuracy.
3. To appreciate the caveats in using bone maturation to determine chronological age.
Age assessment is an important, yet complex and challenging issue that authorities may need to perform to determine whether an individual is an adult or a child in circumstances where their age is unknown. There is currently no method which can identify the exact age of an individual and there are concerns about the invasiveness and accuracy of the methods in use, namely analysis of documentary evidence, interviews, physical or other form of medical examination such as imaging. The main imaging methods include carpal, collar bone and dental examinations. Whilst many countries make use of these methods they do not apply them in the same way and often use different combinations and/or order. One of the main reasons for this is the fact that age assessment procedures remain to a large extent determined by national legislation, with procedures evolving through national jurisprudence (Ref.: European Asylum Support Office (EASO Age Assessment Practice in Europe)). During this session, different methods of bone age assessment, their precision and accuracy will be addressed by experts within the field, followed by a presentation/discussion on ethical and legal aspects of using bone age to determine age.
1. To learn about current medical indications for bone-age assessment.
2. To become familiar with the different methods.
3. To understand the differences between the different methods.
The use of appropriate methods for determining the age is necessary for medical, medico-legal, and sporting contexts. Paediatric endocrinologists have an important interest for bone maturation to evaluate children for advanced or delayed growth and physical development. The developmental status of a child can be assessed by analysing various parameters such as height, weight, secondary sexual characteristics, bone age (BA) and dental age. The factors determining a normal skeletal maturational pattern are not clearly defined; however, genetic, nutritional, metabolic, social and emotional as well as environmental factors and hormones have an impact on bone development. BA assessment is a common procedure used in the management of children with various endocrinopathies and growth disorders. A significant discrepancy between BA and chronological age (CA) indicates abnormalities in skeletal development. When integrated with other clinical findings, clinicians can separate the normal from the relatively advanced or retarded physical development. The literature concerning age assessment, especially hand and wrist radiographies is oversized. Besides chronological methods, some morphological methods can be performed with a citation method (Tanner-Whitehouse, Fels, Sempé, Fishman) or with an atlas (Greulich and Pyle [GP], Gilzang-Ratib, Thiemann-Nitz-Schmeling). Different automated software have been developed for this purpose. The future seems to be represented by non-ionizing techniques like MRI. Nevertheless, the GP atlas, published in the 1950s, is still the most world-wide used method, although the reference sample compared to contemporary European population presents a different socio-economic status and a different ethnics.
1. To learn about an automated radiographic method.
2. To understand the difference between the method’s precision and its accuracy.
3. To acknowledge the need for different reference standards by ethnicity.
The automated method for assessing bone age from radiographs has recently been extended up to 19 years of bone age for boys. The precision of the automated method is defined as its ability to give the same results on repeated x-rays of the hand, and it is reported as the SD = 0.18 years of such repeated determinations. Manual reading by different rater has a precision error of SD = 0.58 years. The accuracy of the automated method is defined as the SD error when compared to manual rating and it has been determined to be 0.75 years, when comparing to a single rater and to 0.52 years when compared to the average of many raters. When the automated method is used to predict the age, the accuracy is larger, with SD approx. 1 years. This holds for Caucasians in Western Europe; for other populations, the age assessment is biased to the extent that maturation proceeds differently in these populations. This has been studied by the automated method by presenting bone age reference curves, where the average bone age advancement (i.e. average BA-CA, BA = bone age, CA = chronological age) is shown versus CA. Such curves have been established for eight populations. The magnitude of BA-CA can be up to 1 year, in particular at the end of puberty. Such differences should be taken into account when using bone age to estimate age, so new studies need to be performed in countries wherefrom asylum seekers originate.
1. To learn about MRI in the assessment of bone age.
2. To become familiar with the method's precision and accuracy.
3. To appreciate potential pitfalls.
Magnetic resonance imaging (MRI) emerged as a potential technique in the assessment of bone age maturity in the context of international football competitions supported by the Fédération Internationale de Football Association - FIFA - due to the need to estimate the ‘real’ age of healthy adolescent football players. Meanwhile, the clinical use of MRI in the assessment of bone age is limited to the field of endocrine disorders related to alterations in developmental age. Lately, and due to war situation in different countries, MRI has been proposed as a forensic tool to establish the age of migrant unaccompanied children without official documents evidencing their ‘real’ age. MRI technique not only avoids the radiation that conventional radiography leads to but also provides detailed image of the growth plate. With this purpose, several groups in the world have been working with different magnetic fields (0.2, 0.3, 1.5, 3T), sequences and gradients (T1 tse, ge, vibe/flash, T2, PD, FFE), body areas (wrist, hand, clavicle, knee, ankle), grade scales and consequently with different results. The majority of the studies have been conducted with males and Caucasians. No consideration regarding other potential factors of influence such as ethnicity, gender, height and weight, nutritional level and socioeconomic factors was taken into account. Whatever the purpose to use MRI for assessment of bone age, there is a pressing need to coordinate our efforts to get consensus not only elaborating standard MRI protocols and grade scales to use, but also in other influencing factors.
1. To understand the difference between bone age as "a marker of disease", and "a substitute for age".
2. To become familiar with ethical aspects.
3. To appreciate legal aspects.
Numerous bone age (BA) methods have been used by clinical practitioners in assessing growth or developmental disorders. BA does not reflect the child’s chronological age, which is an objective element that does not take account of individual variability. Many studies carried out in diverse populations have not always yielded concordant results, but one constant finding emerges: large individual variability exists whatever the method. A princeps study, revealed a link between socioeconomic, health level and BA. The existence in the Greulich and Pyle (GP) atlas of age categories of up to 19 years in boys may perpetuate the illusion that the GP atlas enables classification of individuals aged under or over 18 years. It appears indispensable to apply the recommendations of the Study Group for Forensic Age Estimation. To assess the age of persons who are assumed to be at least 18 years, an additional CT examination of the clavicles is possible. The use of methods of BA estimation in a judicial context raises a number of ethical problems, especially for a delinquent minor. The width of the prediction intervals and the limits of agreement make it possible to emphasize some restrictions when a BA method is used to estimate the age of an individual in a judicial context. In individuals with a bone age of more than 10 years, the prediction interval is nearly 4 years. This raises the question of whether it is relevant to use bone age in judicial context.