Slobodan Nikolić

Frequency and severity of injuries in correlation with the height of fall

The main aim of this study was to examine the correlation between the height of fall and the frequency, extensiveness, and type of injuries of certain body regions and organs. The specific objective was to determine characteristic injuries of the analyzed body regions in relation to the certain height of fall. The study included 660 cases of fatal falls from height (469 males and 191 females). Results support the hypothesis that the frequency and extent of the injured body regions and organs are related to the fall height. Head injuries are characteristic of the falls from heights up to 7 m and beyond 30 m. Brain injuries in high falls from heights beyond 30 m show an absence of contre coup contusions and macroscopically evident intracranial bleeding. The extensiveness of chest injuries is significantly statistically associated with fall height. In cases of high falls, the frequency of abdominal injuries is not significantly statistically related to the height of fall. Liver injuries are the most common abdominal injury and the critical height of fall at which the liver injury occurs is 15 m. Injuries of liver and spleen are concomitant in high falls from heights beyond 24 m, irrespective of the manner of impact. The height of fall over 15 m appears to be a reasonable boundary height beyond which the injuries of two or three body regions are generally associated.

Analysis of neck injuries in hanging

Retrospective study of suicidal hangings was made on 175 cases (133 male victims, 42 female victims) for a 5-year period. The mean age was 47.33 ± 17.51 years. The sample was divided in 4 groups according to the position of the ligature knot (anterior, right, left, and posterior hanging). The authors analyzed all visible injuries of soft tissues and bones and cartilage of the neck, and in 150 cases (85.7%), we established that there was at least one injury of these structures (hematoma or fracture for example). The most frequent injury was to sternocleidomastoid muscles. Fracture of throat skeleton was detected in 119 cases (68%). The proportion of fractures increases with age of the deceased. There was no clear correlation between frequency of neck injuries and type of hanging.

Micro-structural basis for particular vulnerability of the superolateral neck trabecular bone in the postmenopausal women with hip fractures

In this study we analyzed the trabecular bone micro-architecture in the inferomedial and superolateral subregions of the femoral neck in a group with hip fractures and a control group of elderly women, with aim to clarify the micro-structural basis of bone fragility. Proximal femora from 29 Caucasian female cadavers were collected at Institute of Forensic Medicine in Belgrade (15 women with hip fracture: age 79.5±8.5 yrs.; and 14 women without hip fractures: age 74.1±9.3 yrs.). The femoral neck section was scanned in dry conditions using a micro-computed tomography (Scanco μCT 40), at 70 kV, 114 μA, 300 ms integration time, 36 μm resolution, isotropic, 1024×1024 pixels per slice, automatically evaluating trabecular micro-architecture using the built-in program of the micro-CT with direct 3D morphometry. The samples were foam padded to avoid any movement artifacts during scanning. Analysis of the neck section in the fracture group compared to the control cases demonstrated significantly lower bone volume fraction (mean: 6.3% vs. 11.2%, p=0.002), lower connectivity density (0.33/mm(3) vs. 0.74/mm(3), p=0.019) and higher trabecular separation (0.87 mm vs. 0.83 mm, p=0.030). Division into the superolateral and inferomedial regions of interest revealed that the superolateral neck displayed even more differences in micro-architectural properties between the fracture and non-fracture groups. Namely, while in the inferomedial neck only bone volume fraction and degree of anisotropy displayed significant inter-group variability (lower BV/TV with higher degree of anisotropy in the fracture group), in the superolateral neck almost all parameters were different between the fracture cases and the controls, where the fracture group showed a lower trabecular bone volume fraction (3.6% vs. 8.2%, p=0.001), lower connectivity (0.21 vs. 0.63/mm(3), p=0.008), more rod like trabecular structure (SMI: 2.94 vs. 2.62, p=0.049), higher separation and the thinned trabeculae (Tb.Sp: 0.89 vs. 0.85 mm, p=0.013; Tb.Th: 0.17 vs. 0.20 mm, p=0.05). In addition, after adjusting for the effects of BV/TV, the majority of differences disappeared, demonstrating that the bone loss manifests itself via the changes in micro-architectural parameters: trabecular thinning, rising the spacing between individual trabeculae, reducing trabecular connectivity and accentuating trabecular perforations leading to predominance of rod-like trabecular elements. Preferential impairment of the superolateral neck trabecular structure and organization in women with hip fracture reveals the region-dependent micro-structural basis of bone fragility in elderly women.

Evaluation of the Suchey–Brooks Method for Aging Skeletons in the Balkans

ABSTRACT: This study has been carried out to examine whether the Suchey–Brooks (S&B) methods could be successfully applied in age assessment of populations from the Balkans. The known‐age sample consists of 33 females and 52 males pairs of pubic bones collected from the autopsy cases. Age estimation by S&B method showed an accuracy of 89.74% in males and 72.0% in females. Statistical analysis showed a positive correlation between the actual age of the investigated individuals and age phases obtained by the S&B method, although the mean values of the sixth age category differed significantly compared with the original model. The most reliable indicators in both sexes were the relief of the symphyseal surface, lipping, symphyseal rim, and dorsal margin. The discriminating power of these indicators was the least reliable in distinguishing S&B phases 2 and 3. Based on these results, the appropriate recommendations for aging Serbian populations are made. There was a good agreement between two observers (κ=0.726).

Age-related deterioration in trabecular bone mechanical properties at material level: Nanoindentation study of the femoral neck in women by using AFM

Despite general belief that the mechanical properties of bone material contribute to whole bone strength, it is still obscure what the age effects are on mechanical behavior of the bone material, particularly in the case of the femoral neck trabeculae. In this study, atomic force microscopy was used for imaging and measuring the size of mineral grains, as well as nano-scale mechanical characterization (nanoindentation) of the bone mineralized matrix of trabeculae, with the aim to explore the age effects on bone elasticity and give new insight into age-related bone fragility. The bone samples in this study comprised trabecular bone specimens of the femoral neck region, collected from eight skeletal healthy women (five young adults: 27-38yrs., three elderly: 83-94yrs.) at autopsy. Bone trabeculae in the elderly displayed a higher modulus and nanohardness, signifying a decreased amount of energy that can be accommodated by the bone tissue during loading. Regression analysis revealed that nearly 65% of variability in the bone matrix elastic modulus can be statistically explained by the changes in size of the matrix mineral grains. This study revealed that the bone trabeculae of elderly women express less elastic behavior at the material level, which makes them more vulnerable to unusual impact loads originating from a fall. The observed age-related structural and mechanical alteration at the bone material level adds new evidence for understanding why hip fractures are more frequent in elderly women.

Nano-structural, compositional and micro-architectural signs of cortical bone fragility at the superolateral femoral neck in elderly hip fracture patients vs. healthy aged controls.

To unravel the origins of decreased bone strength in the superolateral femoral neck, we assessed bone structural features across multiple length scales at this cortical fracture initiating region in postmenopausal women with hip fracture and in aged-matched controls. Our combined methodological approach encompassed atomic force microscopy (AFM) characterization of cortical bone nano-structure, assessment of mineral content/distribution via quantitative backscattered electron imaging (qBEI), measurement of bone material properties by reference point indentation, as well as evaluation of cortical micro-architecture and osteocyte lacunar density. Our findings revealed a wide range of differences between the fracture group and the controls, suggesting a number of detrimental changes at various levels of cortical bone hierarchical organization that may render bone fragile. Namely, mineral crystals at external cortical bone surfaces of the fracture group were larger (65.22nm±41.21nm vs. 36.75nm±18.49nm, p<0.001), and a shift to a higher mineral content and more homogenous mineralization profile as revealed via qBEI were found in the bone matrix of the fracture group. Fracture cases showed nearly 35% higher cortical porosity and showed significantly reduced osteocyte lacunar density compared to controls (226±27 vs. 247±32#/mm(2), p=0.05). Along with increased crystal size, a shift towards higher mineralization and a tendency to increased cortical porosity and reduced osteocyte lacunar number delineate that cortical bone of the superolateral femoral neck bears distinct signs of fragility at various levels of its structural organization. These results contribute to the understanding of hierarchical bone structure changes in age-related fragility.

Nanostructure and mineral composition of trabecular bone in the lateral femoral neck: implications for bone fragility in elderly women.

Despite interest in investigating age-related hip fractures, the determinants of decreased bone strength in advanced age are not clear enough. Hitherto it has been obscure how the aging process affects the femoral neck nanostructure and composition, particularly in the lateral subregion of the femoral neck, which is considered as a fracture-initiating site. The femoral bone samples used in this study were obtained at autopsy in 10 women without skeletal disease (five younger: aged 20-40 years, and five elderly: aged 73-94 years). Atomic force microscopy (AFM) was applied to explore the mineral grain size in situ in young vs. old trabecular bone samples from the lateral femoral neck. The chemical compositions of the samples were determined using inductively coupled plasma optical emission spectroscopy and direct current argon arc plasma optical emission spectrometry. Our AFM study revealed differences in trabecular bone nanostructure between young and elderly women. The mineral grain size in the trabeculae of the old women was larger than that in the young (median: 95 vs. 59nm), with a particular bimodal distribution: 45% were small grains (similar to the young) and the rest were larger. Since chemical analyses showed that levels of calcium and phosphorus were unchanged with age, our study suggests that during aging the existing bone mineral is reorganized and forms larger aggregates. Given the mechanical disadvantage of large-grained structures (decreased material strength), the observed nanostructural differences contribute to our understanding of the increased fragility of the lateral femoral neck in aged females. Moreover, increasing data on mineral grains in natural bone is essential for advancing calcium-phosphate ceramics for bone tissue replacement.

Characteristics of chest injury in falls from heights

This study included 660 victims injured due to high fall. All cases are with injuries caused by the free-fall model of high fall. The range of the heights was from 0 to 70 m. The sample was divided into three groups of growing height: low falls up to 7 m, high falls from 7 to 30 m, and very high falls above 30 m. Statistical analysis was performed using two way ANOVA according to Scheirer-Ray-Hare in complete uneven block. Males were 71% (469), females 29% (191). In the analyzed sample, apart from the height of fall, the number of accidents is about 44% (290 cases) and suicides about 56% (370 cases). Thirty six percent, i.e., 238 of 660 victims had consumed alcohol before death (alcoholemia >0.5 per thousand). The objective of our study was to analyze characteristics of chest injuries made by falling from a height. The frequency of thoracic injuries is statistically significantly related to the height of fall (p<0.05); it increases constantly in falls from heights beyond 3m, so that the rib fractures were present in all falls from heights beyond 40m. The aortic ruptures were found in 21%, and the heart injuries in 16% of all cases. The frequency of aortic and heart ruptures was not statistically significantly related to the height of fall (p>0.05). A rupture of the aorta was the most commonly located on its arch (82%). The heart ruptures were the most commonly located on the atrial posterior wall (70%).

Enhanced trabecular micro-architecture of the femoral neck in hip osteoarthritis vs. healthy controls: a micro-computer tomography study in postmenopausal women

PurposeA controversial relationship between osteoarthritis (OA) and bone fragility has been attracting considerable attention. However, despite interest in the effects of OA on femoral neck fracture risk and numerous studies analysing the changes in the arthritic femoral head, there is insufficient data about femoral neck 3D bone micro-architecture in individuals with hip osteoarthritis. We compared trabecular micro-architecture of the femoral neck between postmenopausal women with coxarthrosis and controls to explore whether coxarthrosis may indicate reduced bone fragility from the trabecular micro-architectural perspective.MethodsThe study sample included nine women with hip osteoarthritis and 13 age-matched controls. The femoral neck sections were scanned using micro-computed tomography, evaluating the cancellous bone from the superolateral and inferomedial neck subregions.ResultsOsteoarthritic subjects demonstrated a general trend of improved trabecular micro-architecture in both analysed subregions when compared with age-matched controls. In particular, several architectural properties that are important predictors of cancellous bone strength showed significantly better values in the OA group, even after adjusting for bone volume fraction. Namely, the OA group expressed higher trabecular connectivity (p = 0.008), lower SMI indicating more plate-like structure (p = 0.005), and reduced anisotropy (p = 0.006) particularly in the inferomedial neck. Osteoarthritic cases also trended towards higher BV/TV, particularly in the superolateral neck. All micro-architectural parameters displayed significant regional heterogeneity (p ≤ 0.01), with the inferomedial neck region showing more favourable values than the superolateral region.ConclusionsEnhanced trabecular micro-architecture of the femoral neck in postmenopausal osteoarthritic subjects suggests reduced cancellous bone fragility in comparison with their age-matched healthy controls.

Mechanisms of aortic blunt rupture in fatally injured front-seat passengers in frontal car collisions: an autopsy study

We tried to explain the mechanisms of the aortic blunt ruptures in fatally injured drivers and front passengers, unrestrained by seatbelts, by analyzing the frequencies of both aortic ruptures and concomitant injuries to 12 organs and body regions. The sample consisted of 393 subjects: 251 drivers and 142 front passengers (325 male and 68 female passengers, the mean age 41.0 ± 15.5). The total number of the complete blunt aortic ruptures in the sample was 116 (80 in the drivers and 36 in the front passengers). The weakest part of the aorta seems to be the isthmus (47 isthmus ruptures in the drivers and 27 in the front passengers). The statistically significant concomitant injured organs and body regions with the aortic ruptures were the liver, the sternum, and the diaphragm in the car drivers and the head and the neck in the front passengers. According to these results, the mechanisms of thoracic aorta rupture are different for fatally injured drivers and front passengers. For car drivers, they are associated and simultaneous with both thoracic and abdominal compression due to deceleration of the body at the moment when the drivers body slides forward and flexes across and against the steering wheel. For the front passengers, the mechanism is the caudorostral hyperextension of the thoracic aorta at the moment when the body is stopped by a dashboard, but the head continues forward with great velocity: the carotid vessels pull the aortic arch forward at the same time as the intercostal arteries fix the thoracic part of the aorta and pull it downwards.