Reference data for the Thiemann-Nitz method of assessing skeletal age for the purpose of forensic age estimation

Forensic age estimation at the University Center of Legal Medicine Lausanne-Geneva: a retrospective study over 12 years

With the undeniable increase in asylum requests from unaccompanied alleged minors, age estimation of living individuals has become an essential part of the routine work in European forensic centers. This study aims to review the forensic age estimations performed in our center since 2010, to evaluate the state-of-the-art of this practice in Switzerland with the evolution of the methodology according to upcoming recommendations. Our institute's expert reports performed between 2010 and 2022 were retrospectively analyzed. We gathered the following parameters: demographic data, morphological characteristics, alleged age compared with the assessed minimum age, sexual maturation, dental and bone age. When available, we collected personal and family history, medical history, records of torture-related/self-inflicted injuries, and information about eating habits that might affect skeletal development. Data collection amounted to 656 cases. Forensic age estimations ordered by the Swiss Secretariat for Migration (SEM) represented 76.4% of cases, with 23.6% of them ordered by the Court/Public Prosecutor. Most alleged minors were male (94.5%) and came from Afghanistan (53.4%). Adjunction of CT scans of the sternoclavicular joints was necessary in 86.4% of cases. Only 25.2% of our reports concluded on most probable minority, with 55.6% of definite majors; in 19.2% of our cases, minority could not be excluded. This study aspires to further broaden our expertise regarding forensic age estimations. Given the increasing migratory flows, we can expect a notable increase in the frequency of these requests. Consequently, this study aims to promote a multidisciplinary approach and the international standardization of the methodology of these estimations.

Ultrasonographic evaluation of the wrist and elbow joints: A pilot study to explore a non-invasive technique for age estimation

Age estimation is a vital aspect of the process of identification. Studying the appearance and fusion of long bones is one of the most commonly used methods for age estimation. Most research conducted on age estimation using the study of the appearance and fusion of ossification centres has been roentgenographic in nature. However, X-ray examination and computed tomography examination are associated with ionisation radiation. The present study investigated the use of ultrasonography (USG) as a means of visualising ossification centres of the elbow and wrist joints for age estimation in 31 Maharashtrian boys from Ahmednagar, India. The Schmeling et al. method of grading was used to score the fusion of ossification centres, and simple and multiple linear regression models were developed for age estimation. It was found that the ossification centres of the elbow and wrist joints followed a set pattern of maturation and fusion. The ossification centres of the elbow joint fused before the ossification centres of the wrist joint. The fusion scores of proximal radial epiphyses had the highest correlation with the decimal age of the participants, making its fusion the best indicator among all the ossification centres examined in this study for age estimation. Regression models to estimate age were generated using all the ossification centres. USG was found to be suitable for the purpose of age estimation based on ease of examination, minimal ionisation risks, its non-invasive nature and clear visualisation of ossification centres.

Dentistry to the rescue of missing children: A review

Today's society is becoming increasingly unsafe for children: we frequently hear about new incidents of missing children, which lead to emotional trauma for the loved ones and expose systemic failures of law and order. Parents can take extra precautions to ensure the safety of their children by educating them about ways to protect themselves and keep important records of the child such as updated color photographs, fingerprints, deoxyribonucleic acid (DNA) samples, etc., handy. However, in spite of all efforts, the problem of missing children still remains. Developments in the field of dentistry have empowered dentists with various tools and techniques to play a pivotal role in tracing a missing child. One such tool is Toothprints, a patented arch-shaped thermoplastic dental impression wafer developed by Dr. David Tesini, a paediatric dentist from Massachusetts. Toothprints enables a unique identification of the missing children not only through the bite impression but also through salivary DNA. Besides the use of Toothprints, a dentist can assist investigating agencies in identifying the missing children in multiple ways, including postmortem dental profiling, labeled dental fixtures, DNA extraction from teeth, and serial number engraving on the children's teeth. More importantly, all these tools cause minimal inconvenience to the individual, making a dentist's role in tracking a missing child even more significant. Thus, the simple discipline of maintaining timely dental records with the help of their dentists can save potential hassles for the parents in the future.

Forensic Age Estimation

BACKGROUND

Forensic age estimation is requested by courts and other government authorities so that immigrants whose real age is unknown should not suffer unfair disadvantages because of their supposed age, and so that all legal procedures to which an individual's age is relevant can be properly followed. 157 age estimations were requested in Berlin in 2014, more than twice as many as in 2004.

METHODS

This review is based on pertinent articles retrieved by a selective search in the PubMed and MEDPILOT databases, supplemented by relevant recommendations and by the findings of the authors' own research.

RESULTS

The essential components of age estimation are the history, physical examination, X-rays of the hands, panorama films of the jaws, and, if indicated, a thin-slice CT of the medial clavicular epiphyses, provided that there is a legal basis for X-ray examinations without a medical indication. Multiple methods are always used in combination, for optimal accuracy. Depending on the legal issues at hand, the examiner may be asked to estimate the individual's minimum age and/or his or her most probable age. The minimum-age concept can be used in determinations whether an individual has reached the age of legal majority. It is designed to ensure that practically all persons classified as adults have, in fact, attained legal majority, even though some other persons will be incorrectly classified as minors.

CONCLUSION

Forensic age estimation lets courts and other government authorities determine the official age of persons whose actual age is unknown-in most cases, unaccompanied refugees who may be minors. The goal is to carry out age-dependent legal procedures appropriately in accordance with the rule of law. The minimum-age concept is designed to prevent the erroneous classification of minors as legal adults.

Ages of legal importance: Implications in relation to birth registration and age assessment practices

Assessment of age is a common procedure routinely conducted in many countries following birth date disputes, particularly following asylum claims and criminal offenses. UNICEF reports that only 65% of children in the world were registered, and the numbers of children who possess an authentic birth certificate were significantly lower than those registered. Legally important ages can be categorized into defined age ranges that vary among different countries. Recently, following an increase in the number of age-specific crimes, many countries have revised their legally important ages. This article is intended to report the most recent data on the ages of legal importance in the major countries of the world and implicate its relevance to birth registration and age assessment practices.

Intercanine width as a tool in two dimensional reconstruction of face: An aid in forensic dentistry

Context:

Dental evidence is a valuable tool in identifying individuals, especially when disasters befall. Reference points in faciomaxillary region such as interpupillary distance, intercanthal distance, interalar distance and bizygomatic width can significantly contribute toward reconstruction of two-dimensional (2D) facial profiles. This study was researched upon to determine the relationship between the maxillary intercanine width and the different reference points of the face.

Aim:

The aim of the following study is to ascertain whether maxillary intercanine width can be used to detect interpupillary distance, intercanthal distance, interalar distance and bizygomatic distance and to evaluate the role of maxillary intercanine width in the 2D reconstruction of the face.

Materials and Methods:

The study was carried out by consent and involved 90 subjects-45 males and 45 females who satisfied the inclusion criteria. Subjects were divided into three age groups, i.e. 18-24, 25-28, 29-35. Four parameters were measured– intercanine width, interpupillary distance, intercanthal distance and interalar distance. All the measurements were carried out with a digital Vernier caliper. The bizygomatic width was measured from posterior-anterior view. Two empiricists were assigned for the task. Each test was carried out twice to validate the soundness of the findings and to reduce bias.

Statistical Analysis:

Analysis of variance and Pearson correlation was established. Regression analysis was performed to predict the study variables by intercanine width.

Results:

Intercanine width showed a significant relationship with different points. The width varied with age and gender.

Conclusion:

Inter canine width can be used as a valuable parameter in the reconstruction of face in two dimensional as it shows significant relationship with faciomaxillary reference point such as interpupillary distance, intercanthal distance, interalar distance and bizygomatic width.

Correlation between age and the parameters of medial epiphysis and metaphysis of the clavicle using CT volume rendering images

OBJECTIVES

The aim of this study was to evaluate the correlation between age and the parameters of medial epiphysis of clavicle based on CT volume rendering (VR) images.

MATERIALS AND METHODS

The CT images of the medial clavicle from 795 teenagers (387 male and 408 female) between 15 and 25 years were collected in East and South China. VR images were recombined from 0.60 mm thickness slice CT images. The ratio of epiphyseal diameter/metaphyseal diameter and the ratio of epiphyseal area/metaphyseal area of two sides of medial clavicle were measured and calculated by three different examiners, the quantitative data consistency was checked by intraclass correlation coefficients (ICC). The diameter ratio of left and right side are depicted as X1 and X3, and the area ratio of left and right side as X2 and X4. Descriptive statistic analysis of the data was performed and several mathematical models were established using least square. CT images from additional 60 teenagers (30 male and 30 female) were used to verify the accuracy of the established mathematical models.

RESULTS

ICC indicated that the measurement of epiphyseal diameter, metaphyseal diameter, the ratio of epiphyseal diameter/metaphyseal diameter, epiphyseal area, metaphyseal area and the ratio of epiphyseal area/metaphyseal area of medial clavicle in the left and right side of the three examiners was approaching 1. The 95% reference range for the mean of every examination of both genders gradually increased with age. Females' data indicated by medial epiphysis of the clavicle development were earlier than male's, especially from 15 to 21 years. The difference of medial epiphysis of the clavicle development in gender becomes smaller after 21 years. The highest accuracy of the mathematical models made clear that male's accuracy was 73.5% (±1.0 year) and 85.3% (±1.5 year), and female's was 68.6% (±1.0 year) and 82.2% (±1.5 year) respectively.

CONCLUSION

The methods of data collection and analysis were reliable and feasible. Combined the high accuracy of these established mathematical models, it is applicable to use the ratio of epiphyseal diameter/metaphyseal diameter and the ratio of epiphyseal area/metaphyseal area of left and right side of medial clavicle to estimate the teenager's age. Bearing this in mind, further studies are needed to evaluate slice thickness as the most critical parameter.

Comparative study of Greulich and Pyle Atlas and Maturos 4.0 program for age estimation in a Portuguese sample

Age estimation of living individuals has become one of the big issues of forensic anthropology. The increase of children and adolescents with no valid proof of their chronological age is a legal concern to many countries, especially in situations of illegal immigration, sub adult delinquency and juvenile work. For this purpose, the use of radiological methods for evaluation of skeletal maturation is particularly useful. In this study we compare the two of the most common methods applied in age estimation by hand/wrist radiographs: the Radiographic Atlas of Skeletal Development of the Hand and Wrist made by Greulich and Pyle (GP), 1959,and the Sempé method developed for computer--Maturos 4.0 (MT) program. These methods were applied to a sample of 230 radiographs of the hand and wrist from Portuguese children and adolescents of known sex age and age, aged between 12 and 20 years, who performed medical examination at the University of Coimbra Hospitals during 2005. The methods achieved different performances, depending on the age group. Between 12 and 15 years the bone age with the MT program is closer to the chronological age, whereas in older ages the GP Atlas method is more trustworthy. At the ages with legal consequences in Portugal (16 and 18 years) the GP Atlas method is most accurate, namely to decide whether an individual is younger or older than 18 years. Around 16 years old, although there are doubts in relation to the accuracy of both methods, GP Atlas seems to perform better.

Enhanced possibilities to make statements on the ossification status of the medial clavicular epiphysis using an amplified staging scheme in evaluating thin-slice CT scans

Thin-slice computed tomography provides the imaging modality of choice in analysing the ossification process of the medial clavicular epiphysis for the purpose of forensic age diagnostics in the living in the course of criminal proceedings. The classification of the ossification stages by Schmeling et al. compass the emergence of an epiphyseal ossification centre (stage 2), the partial fusion of the epiphysis with the metaphysis (stage 3), the complete fusion of these osseous elements including a visible epiphyseal scar (stage 4), and the complete fusion without a visible epiphyseal scar (stage 5). In the present study, each of the ossification stages 2 and 3 was divided into an early, intermediate and late phase. The authors evaluated the thin-slice CT scans of 185 patients aged between 13 and 26 years. In all these cases, a stage 2 or 3 had been determined in a previous study. The late stage 3, which is characterized by a fusion between metaphysis and epiphysis completing more than two thirds of the former epiphyseal gap, first appeared at age 19 in both sexes. If a late stage 3 is found, it is therefore possible to substantiate that an individual has already reached the legally important age threshold of 18 years.

Evaluation of the radiographic visibility of the root pulp in the lower third molars for the purpose of forensic age estimation in living individuals

The question of whether an individual has reached the age of 18 is of crucial importance in forensic age estimation practice. In some countries, the age threshold of 21 years is relevant as well. A completed mineralization of third molars is not a sufficient criterion for a diagnosis of a minimum age of 18 years with the required probability. In a material of 1,198 orthopantomograms from 629 females and 569 males aged between 15 and 40 years, the visibility of the root pulp of fully mineralized lower third molars was evaluated according to stages 0, 1, 2, and 3. In females, stage 0 was first noticed at age 17.2 years, in males at age 17.6 years. In either sex, the earliest observation of stage 1 was between 21.0 and 22.4 years. Stage 2 was first achieved by males between 22.3 and 22.7 years, by females between 23.4 and 24.7 years. The occurrence of stage 3 was first found in both sexes between 25.1 and 25.9 years. These findings indicate that for stage 0, an age below 18 years cannot be excluded. However, for stage 1, the examined individual must be over 18 years of age and most probably over 21 years of age. For stages 2 and 3, the age can safely be stated to be over 21 years of age. This method may be a powerful tool for forensic dentists in age estimation in asylum and criminal proceedings.

Ultrasound studies on the time course of clavicular ossification

When preparing forensic age estimates for living subjects over 18 years of age, it is crucial to evaluate the stage of ossification of the medial clavicular epiphysis. The establishment of radiation-free imaging techniques for assessment of clavicular ossification would be desirable in order to reduce the radiation exposure associated with forensic age estimations. In the present study, 84 right clavicles of test subjects 12-30 years of age were prospectively evaluated by means of ultrasound. Ossification stage classification was possible in 80 of the 84 medial clavicular epiphyses studied. In the remaining cases, stage classification was not possible due to the presence of developmental anomalies. The earliest ages at which the respective ossification stages were observed were 17.1 years for stage 2, 16.7 years for stage 3, and 22.5 years for stage 4. The age intervals observed for the ossification stages are consistent with the known data from radiological and computed tomography assessments. The present study results should be confirmed in a larger number of cases and with analysis of observer variability. Evaluation of medial clavicular epiphyseal ossification by ultrasound could ultimately be a rapid and economic non-ionizing diagnostic imaging procedure for forensic age estimation.

Radiographic staging of ossification of the medial clavicular epiphysis

Determination of the stage of ossification of the medial clavicular epiphysis is a crucial part of forensic age estimation when evaluating living subjects over 18 years of age. In the present study, we comparatively assessed conventional radiographs and computed tomography (CT) scans of sternoclavicular joints used to perform forensic age assessments in 57 individuals undergoing criminal proceedings. With CT, it was possible to determine the ossification stage of all clavicles studied. In the case of conventional radiography, reliable assessment of ossification stage was not possible in 15 out of 114 clavicles studied due to the superimposition of other structures. Regarding agreement between the methods, both radiography and CT produced identical staging results in 97 out of 99 clavicular epiphyses. In two cases, however, ossification was classified as stage 2 by CT and as stage 3 by conventional radiography. Regarding stages 4 and 5, both methods produced identical staging results in all cases. In forensic age estimation practice, it is necessary that conventional radiographic reference studies be used for ossification stage classification by conventional radiography and that CT reference studies be used for ossification stage classification by CT. Further studies in dead bodies of known age are required to issue a recommendation as to whether conventional radiography using obtained in three planes or CT is the method of choice for the assessment of clavicular ossification.

Assessment of the accuracy of three-dimensional manual craniofacial reconstruction: a series of 25 controlled cases

The aim of this work was to estimate the accuracy of craniofacial reconstruction (CFR), from a series of 25 controlled cases. Three protocols of blind CFRs (exhibiting an increasing complexity from A to C) were assessed in this paper, allowing comparison of the CFR with the actual face of the deceased. The whole results showed that an excellent, or good, to middle resemblance (between the blind CFR and the actual face of the subject) was reached in 9 out of 25 cases, but the success gradually increased from the A to the C protocol of CFR, reaching six cases out of eight in the latter. Statistical comparison of measurements (between the blind CFR and the actual face) was also achieved, revealing that some anthropological distances were constantly underestimated or overestimated. This experiment shows that a thorough anthropological, odontological, and X-ray analysis is indispensable before performing a CFR, and these encouraging results justify further efforts of research in this field.

Age estimation in children by measurement of open apices in teeth: a European formula

The aim of the present paper was to improve and expand research with a larger number of children from various European countries and to provide a common formula useful for all these countries. Orthopantomographs taken from 2,652 European Caucasian children (1,382 boys, 1,270 girls) aged between 4 and 16 years were analyzed. The children came from Croatia, Germany, Kosovo, Italy, Slovenia, Spain, and the UK. Following the pilot study, subjects' age was modeled as a function of gender (g), morphological variables (predictors) x 5(second premolar), s (sum of normalized open apices) N 0, and the first-order interaction between s and N 0. The results showed that all these variables contributed significantly to the fit, so that all were included in the regression model, yielding the following linear regression formula: Age = 8.387 + 0.282 g - 1.692 x 5 + 0.835 N 0 - 0.116 s - 0.139 s x N 0, where g is a variable, 1 for males and 0 for females. The equation explained 86.1% (R2 = 0.861) of total deviance. The median of the residuals (=observed age minus predicted age) was -0.114 years, with (RefB.2) interquartile range = 1.22 years.

New method for height estimation of subjects represented in photograms taken from video surveillance systems

The article describes a method developed and applied by the authors for the purpose of determining the height of subjects taped on video surveillance systems. The determination of height is obtained by developing a virtual telecamera having the same characteristics of the video surveillance system with which the images have been shot. The results demonstrate that height is a parameter that can be accurately estimated with the method proposed, in the experimental conditions described, and consequently, can be utilized in probatory inquiry.

Comparative study on the effect of ethnicity on wisdom tooth eruption

The current knowledge base for evaluating the influence of ethnic origin on wisdom tooth eruption is still inadequate. We therefore analyzed and compared the chronology of wisdom tooth eruption in three ethnic populations-German, Japanese, and black South African-based on evidence from 2,482 conventional orthopantomograms. The investigated German population ranked in the middle in terms of the age of wisdom tooth eruption. The black South African population was the fastest and the Japanese population the slowest in terms of reaching the respective eruption stages. Population-specific reference data should be used when evaluating wisdom tooth eruption for the purpose of forensic age estimation.

Magnetic resonance imaging of the clavicular ossification

Assessment of the degree of ossification of the medial clavicular epiphyseal cartilage is of vital importance in forensic age diagnostics of living individuals aged more than 18 years. To date, reference studies on the assessment of clavicular ossification using imaging procedures only relate to conventional radiography and computed tomography (CT). In this study, magnetic resonance (MR) scans of 54 sternoclavicular joints of bodies aged between 6 and 40 years were evaluated prospectively. All of the examined medial clavicular epiphyseal cartilages permitted an assessment of the degree of ossification. Stage 2 was first observed at the age of 15.0 years, the earliest age at which stage 3 was observed was 16.9 years, and stage 4 was first observed at the age of 23.8 years. The observed age intervals of the respective degrees of ossification correspond to the known data from X-ray and CT scan examinations. The achieved results should be examined with a larger number of cases. A modified examination protocol is required for the MR examination of the medial clavicular epiphyseal cartilage for the purpose of forensic age diagnostics of living individuals.

Estimation of pediatric skeletal age using geometric morphometrics and three-dimensional cranial size changes

This paper presents a method for estimating the skeletal age of children based on the centroid size of their face and their basicranium, derived from the three-dimensional coordinates of anatomical landmarks. The sample consists of computed tomography scans of 127 children (54 boys, 73 girls) of mixed origin living in the area of Toulouse (France), ranging in age from a few days to 18 years. The purpose of the present investigation was, first, to increase the variety of age-related structures theoretically available for pediatric skeletal age estimation and, second, to devise a method that can be applicable from early postnatal age to the end of adolescence with a satisfactory accuracy independent of age and even a better accuracy with greater age. We examined the relationship between the chronological age and the centroid size, calculated by using geometric morphometric methods and a linear model. With the aid of cross-validations, the statistical analysis indicates that the centroid size of the facial skeleton can be used an age-related variable without any loss of accuracy with increased age, contrary to most of the methods of pediatric age estimation. The standard error was always lower or equal to 2.1 years (at the 95% confidence level) and decreased in our sub-sample of older children represented by a larger number of individuals.

Comparative analysis of the applicability of the skeletal age determination methods of Greulich–Pyle and Thiemann–Nitz for forensic age estimation in living subjects

Evaluation of hand ossification is a main pillar of radiological age diagnosis in living subjects. In the present study, we comparatively assessed the Greulich-Pyle and Thiemann-Nitz methods for accuracy of age estimation and degree of acceleration in the respective reference populations. For this, the skeletal age of 649 hand X-rays from German subjects aged 1-18 years was determined by both methods. Accuracy of the age estimates was determined based on regression and measures of certainty. In terms of accuracy, both methods seem to be equally well suited for forensic age diagnostics. The degree of acceleration in the reference populations for the two methods was calculated as the mean difference between the estimated skeletal age and the actual age of a test subject. Compared to the Greulich-Pyle population, the Thiemann-Nitz population was accelerated by 0.44 years in both male and female subjects. When an expert opinion is required and one cannot exclude the possibility that the investigated subject may come from a population with a high acceleration status, the Thiemann-Nitz method should preferably be used to prevent overestimation of age.

Age estimation of unaccompanied minors

In recent years many countries have experienced a sharp increase in the demand for forensic age estimates of unaccompanied minors. In many countries the age thresholds of relevance to criminal prosecution lie between 16 and 22 years. In line with recommendations issued by the Study Group on Forensic Age Diagnostics, for determining the age of live subjects a forensic age estimate should combine the results of a physical examination, an X-ray of the hand and a dental examination which records dentition status and evaluates an orthopantomogram. To assess the age of persons who are assumed to be at least 18 years old, an additional radiographic or CT examination of the collar bones is recommended. Forensic age estimates should take account of the ethnic origin and socio-economic status of the person under examination.