Individual Bones Research Articles

Investigating the Decreased Bone Density Prevalence in People with Common Risk Factors Referred to Al-Zahra Educational-Medical Center in Isfahan City Years of 2018 and 2019

Introduction: Osteoporosis is a disease in skeletal system that is recognized by a lack of bone density and degeneration of bone tissue and can lead to increase the risk of bone fracture or even death. So, this study was conducted to determine the prevalence of decreased bone density in people with common risk factors referred to Al-Zahra Educational-Medical Center in Isfahan City years 2018-2019.
 Methods: This was a cross-sectional study. 3780 participants were included in the study by census sampling from April 2018 to March 2019. The risk factors considered in this study included gender, age, menopausal age, body mass index, history of mild trauma or fracture after the age of 40, hip fracture, autoimmune diseases, corticosteroid use, diabetes, hypothyroidism, hyperthyroidism, liver diseases, kidney diseases, malnutrition, alcohol consumption, smoking, and weight loss. Patients underwent bone densitometry. The criterion for diagnosing osteoporosis is T score, which indicated the ratio of an individual's bone density to baseline. Data were collected by a checklist and then analyzed in SPSS software version 16 at a significance level of 0.05.
 Results: The hip T-score in 1780 (47.1%) individuals and the spine T-score in 1724 (45.6%) individuals were between -1 and -2.5. There was a significant relation among gender, age, height, weight and body mass index, corticosteroid use, chronic kidney disease, premature menopause, hyperthyroidism, weight loss, autoimmune diseases, hip fracture, and the history of trauma or fracture after the age of 40. hip T score, and there was a significant relationship between age, height, weight and body mass index, hyperthyroidism, weight loss, premature menopause, corticosteroid use, (P> 0.05). Spine T score was related to factors such as age, height, weight and body mass index, hyperthyroidism, weight loss, early menopause, corticosteroid use, history of trauma or fracture after 40 years (P<0.05).
 Conclusion: This study showed that the prevalence of osteoporosis increases with age, and especially women with early menopause, and also in people with a history of trauma or fracture over the age of 40, hip fracture, corticosteroid use, hyperthyroidism, and autoimmune disease, chronic kidney disease, obesity and weight loss are common. Therefore, in order to prevent osteoporosis, necessary measures should be taken to prevent and correct the risk factors.

Bioprinting for bone tissue engineering.

The shape transformation characteristics of four-dimensional (4D)-printed bone structures can meet the individual bone regeneration needs, while their structure can be programmed to cross-link or reassemble by stimulating responsive materials. At the same time, it can be used to design vascularized bone structures that help establish a bionic microenvironment, thus influencing cellular behavior and enhancing stem cell differentiation in the postprinting phase. These developments significantly improve conventional three-dimensional (3D)-printed bone structures with enhanced functional adaptability, providing theoretical support to fabricate bone structures to adapt to defective areas dynamically. The printing inks used are stimulus-responsive materials that enable spatiotemporal distribution, maintenance of bioactivity and cellular release for bone, vascular and neural tissue regeneration. This paper discusses the limitations of current bone defect therapies, 4D printing materials used to stimulate bone tissue engineering (e.g., hydrogels), the printing process, the printing classification and their value for clinical applications. We focus on summarizing the technical challenges faced to provide novel therapeutic implications for bone defect repair.

Quaternary ungulates of the Abismo Ponta de Flecha Cave, Ribeira of Iguape Valley, Southeast Brazil: Zooarchaeological and Paleoenvironmental aspects

The Ribeira de Iguape Valley, located in the south of the state of São Paulo, presents a complex system of caves developed from Precambrian carbonate rocks. The presence of such karstic system favored the preservation of numerous fossilized remains of Quaternary mammals. The Abismo Ponta de Flecha Cave, located in the municipality of Iporanga, is a vertical cave divided into several lateral galleries with abundant vertebrate specimens. Among the most common are the ungulates, a clade of mammals characterized mainly by the presence of hooves, represented by the Holoarctic ungulates families Cervidae, Tayassuidae, Tapiridae, and the South American native ungulate Toxodontidae. The most common family in the deposit is Tayassuidae, with several individuals assigned to the species Tayassu pecari, Dicotyles tajacu, as well as an indeterminate large Tayassuidae. The Cervidae remains found in the cave have two species assigned to the genus Mazama; M. americana and M. gouazoubira. A specimen of the Tapiridae family, Tapirus sp., was also found. Only one species attributed to the extinct family Toxodontidae, Toxodon platensis, was recorded. Many specimens of Tayassuidae and Cervidae were subadults, and one individual of Tayassu pecari was very young. The origin of the specimens might be the result of the transport of individual bone parts, the death of accidently trapped animals as well as the disposal of such remains by human groups that inhabited the region in the past.

Pursuing the Clonal Dynamics of Minimal Residual Disease (MRD) in Relapsed and Refractory Acute Myeloid Leukemia

Acute Myeloid Leukemia (AML) is a myelogenous malignancy that frequently relapses despite complete remission (CR) and elicits non-responsiveness (refractory) to treatment. Recent studies have emphasized that acquiring resistance to treatment and/or residual subclones bearing drug persistency such as Cancer stem cells (CSCs) or Minimal residual disease (MRD) clones can lead to relapse and treatment-refractory in AML. However, due to the AML's cytogenetic clonal heterogeneity, drug persistent MRD having leukemogenic properties and its clinical relevance have not yet been fully explained. In this study, we investigate the clonal dynamics of AML MRD by pursuing their genotypic/phenotypic changes in the individual AML patient's Bone Marrow (BM) niche. To investigate, we collected longitudinal BM samples at diagnosis (Dx), remission (CR), relapse (Rel), and treatment-refractory (Per) from two patients of relapsed/refractory AML. By bulk Whole Exome Sequencing (WES), somatic variants were analyzed, and selected four oncogenic variants (Patient #01: FLT3 D835E, WT1 R375Pfs; Patient #02: KIT D816Y, ASXL1 A722L) showing a significant change according to the treatment process. Seven blood cell fractions (4 HSPCs, Hematopoietic Stem and Progenitors: HSC/MPP, LMPP, CMP/MEP, GMP, LSC-like populations; 3 Mature leukocytes: Myeloid cells, T/B Lymphocytes) from AML patient's bone marrow samples were sorted by cell surfaces antigens. Selected AML-associated variants were detected by droplet digital PCR (ddPCR) in DNA of each sorted seven single cell fractions. In the AML patient BM, we found that the clones with an oncogenic (or likely oncogenic) variant were distributed in not only primitive cell populations with the HSPC (LSC-like) phenotype, but also mature (differentiated) cell populations such as leukocytes. These clones were not completely disappeared even after intense AML chemotherapy, and remained in minimal quantities. In our sequential analysis, some residual clones distributed in LSC-like populations exhibited the traditionally well-known MRD's character, such as repopulating LSC proportions. Furthermore, some other residual clones only in mature populations also seemed to be played a role in functional MRD resulting in the repopulation of LSCs. However, whether these residual clones in LSC-like populations or mature populations eventually induced repopulating of LSC-like fractions during AML relapse, and particularly in the relapse before an endpoint, these clones also tended to be highly enriched in LSC-like populations by 30% (based on the VAF). While the variant clones in mature populations may be the temporal salvages of AML-MRD clones (functional MRD) to survive against treatment, the variant clones in LSC-like populations might be the AML-MRDs practically contributing to AML recurrence and treatment-refractory. This approach suggests the methodology for specifying AML-MRD and pursuing its clonal evolution according to the treatment progress. This will help to improve AML risk stratification and the diagnostic methodology, enabling the preemptive detection of AML MRD at the initial diagnosis/treatment. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Density functional theory demonstrates orientation effects in the Raman spectra of hydroxy‐ and carbonated apatite

AbstractRaman spectroscopy is widely used to examine the carbonate content within bone apatite, but Raman spectra are also sensitive to orientation effects between the polarisation of the incoming laser light and the sample orientation. This may lead to discrepancies when using Raman spectroscopy to evaluate the carbonate content as the extent of crystal organisation can change depending on the type of bone, age, and presence of mineralisation disorders in the organism. It is experimentally very challenging to evaluate the effect of orientation using individual bone crystals. Therefore, we have used density functional theory to examine the effect of orientation in apatitic materials. We examined hydroxyapatite and three different types of carbonated apatite: A‐type where the carbonate ion substitutes the two OH groups in the unit cell, B‐type where co‐substitution occurs between carbonate in a phosphate position and Na+ for Ca2+ to maintain charge balance, and AB‐type where carbonate sits in both A‐site and B‐site. Our simulations show that the OH group in hydroxyapatite has a strong orientation dependence, consistent with previous literature. In addition, the phosphate and carbonate bands of the apatitic structures are predicted to be orientation dependent, where the maximum scattering efficiency occurs in configurations in which the laser polarisation is parallel to the crystallographic axes of the material. The intensity changes of the phosphate and carbonate bands are not consistent upon changing orientations and thus may lead to an underestimation of carbonate contents if insufficient sampling points are used during bone analysis.

Development of the sphenoid sinus from newborn to age 18: A computed tomography imaging analysis

The sphenoid sinus (SS) is an important anatomical formation in terms of its location and relationship with important neurovascular structures. It is essential to evaluate the pneumatization and dimensions of the SS with Computed Tomography (CT) in the preoperative period of transsphenoidal interventions to be performed on tumors located in this region. The aim of this study was to evaluate the correlation of the volume and dimensions of the SS measured with CT with age in the period from birth to 18 years of age. In this retrospective study, a total of 360 brain, paranasal sinus, temporal bone and maxillofacial CT scans of individuals from birth to 18 years of age were evaluated. The cohort was divided into 18 groups with 20 (10 female, 10 male) patients in each age group. The height, width, length and volume values of the SS were measured on CT and their correlations with age and the differences between genders were evaluated statistically. It has been determined that the increases in the size and volume of the SS accelerate especially between 1 and 2 years of age and begins to reach adult dimensions after 12 years of age. Height and length of the sphenoid sinus showed a high correlation coefficient (r=0.717 and r=0.731 respectively) with age, while its width and volume showed a moderate correlation coefficient (r=0.662 and 0.543 respectively). There was no statistically significant difference between the genders in terms of SS height, width, length and volume. SS dimensions and volume showed a logaritmic growth pattern from birth to 18 years. The results of this study may help to better understand the normal development of SS in children and may serve as a reference for more comprehensive CT studies. In addition, it can help surgeons to evaluate the developmental characteristics of SS in surgical interventions for SS in children.

Computed tomography and three-dimensional reconstruction of the skull of the stem tetrapod Crassigyrinus scoticus Watson, 1929

ABSTRACT The early tetrapod Crassigyrinus scoticus was a large aquatic predator known from the lower- to mid-Carboniferous (upper Tournasian to upper Visean/lower Serpukovian, approximately 350–330 Ma) of Scotland and Canada. Crassigyrinus is enigmatic in terms of its phylogenetic position due to its unusual morphology, which features a mixture of primitive and derived characters. Previous reconstructions, based on five incomplete and deformed specimens, have suggested a dorsoventrally tall skull with a short and broad snout, large orbits and external nares, and an extended postorbital region. In this study, we scanned four specimens using computed tomography and segmented imaging data to separate bone from matrix and individual bones from each other. Based on these data, we present a revised description of the upper and lower jaws, including sutural morphology and abundant new anatomical information. Damage was repaired and the skull retrodeformed to create a hypothetical three-dimensional reconstruction of the skull of Crassigyrinus that is dorsoventrally flatter than earlier reconstructions, yet still morphologically unique amongst early tetrapods. Overall skull shape, the size and distribution of the teeth, sutural morphology, and the specialized anatomy of the jaw joint and mandibular symphysis all suggest that Crassigyrinus was a powerful aquatic predator capable of hunting and subduing large prey.

First evidence of Proganochelys quenstedtii (Testudinata) from the Plateosaurus bonebeds (Norian, Late Triassic) of Frick, Canton Aargau, Switzerland

Proganochelys quenstedtii represents the best-known stem turtle from the Late Triassic, with gross anatomical and internal descriptions of the shell, postcranial bones and skull based on several well-preserved specimens from Central European fossil locations. We here report on the first specimen of P. quenstedtii from the Late Triassic (Klettgau Formation) Frickberg near the town of Frick, Canton Aargau, Switzerland. Similar to other Late Triassic ‘Plateosaurus-bearing bonebeds’, Proganochelys is considered to be a rare faunal element in the Swiss locality of Frick as well. The specimen, which is largely complete but was found only partially articulated and mixed with large Plateosaurus bones, overall resembles the morphology of the classical specimens from Germany. Despite being disarticulated, most skull bones could be identified and micro-computed tomography (CT) scanning of the posterior skull region reveals new insights into the braincase and neurovascular anatomy, as well as the inner ear region. These include the presence of a fenestra perilymphatica, potentially elongated cochlear ducts, and intense vascularization of small tubercles on the posterior end of the skull roof, which we interpret as horn cores. Other aspects of the skull in the braincase region, such as the presence or absence of a supratemporal remain ambiguous due to the fusion of individual bones and thus lack of visible sutures (externally and internally). Based on the size of the shell and fusion of individual elements, the specimen is interpreted as a skeletally mature animal.

Environmental signal in the evolutionary diversification of bird skeletons.

Characterizing how variation in the tempo and mode of evolution has structured the phenotypic diversity of extant species is a central goal of macroevolution1-3. However, studies are typically limited to a handful of traits4-6, providing incomplete information. We analyse morphological diversification in living birds, an ecologically diverse group7, documenting structural scales from 'pan-skeletal' proportions down to the localized three-dimensional shape changes of individual bones. We find substantial variation in evolutionary modes among avian subgroups and among skeletal parts, indicating widespread mosaicism and possible differences in the structure of the macroevolutionary landscape across Earth's main environments. Water-linked groups, especially Aequorlitornithes (waterbirds), have repeatedly explored a large portion of their total morphospace, emphasizing variation in body proportions and in the shape of bones close to the body core, which are functionally related to the mechanics of locomotion8. By contrast, landbirds (Inopinaves) evolved distinct, group-specific body forms early in the aftermath of the K-Pg and subsequently emphasized local shape variation, especially in the head and distal limb bones, which interact more directly with the environment. Passerines, which comprise more than half of all bird species, show a conservative evolutionary dynamic that resulted in low disparity across all skeletal parts. Evidence for early establishment of the morphospace of living birds is clear for some skeletal parts, including beaks and the combined skeletal morphology. However, we find little evidence for early partitioning of that morphospace, contrary to more specific predictions of 'niche-filling' models1,9. Nevertheless, early divergence among broad environmental types may have caused an early divergence of evolutionary modes, suggesting an important role for environmental divergence in structuring the radiation of crown-group birds.

An Epidemiological Analysis of Orthopedic Fractures, a Retrospective Single-Center Study from Jordan

Background: Studies on musculoskeletal fractures are limited in Jordan. Therefore, this study includes all orthopedic fractures in the tertiary center from Jordan. Fractures are evaluated for etiologies, age distribution, gender, mechanism of injury, and associated injuries. Therefore, this could assist in discovering the needs of our healthcare system and endorse recommendations on fracture treatment and prevention. Materials and Methods: This retrospective study reviewed 3,387 fractures admitted from July 2018 to December 2021 at King Hussein Medical City in Amman, the capital of Jordan. Fractures were assessed regarding age, gender, mechanism of injury and variation across years. Fractures were allocated into eleven bones where forearm, hand, leg and foot were considered individual bones to facilitate analysis. Results: The males represented 57.8% of patients. The lower limb was affected in 47.4%, the femur was the most commonly affected bone (26.6%), and the proximal femur accounted for 20.9% of all fractures. Men were more likely to sustain injuries to long bone, hand and foot injuries, while women were at higher risk of fragility fractures. Most hospitalizations were in patients over the age of fifty. Two-thirds of injuries were induced by simple falls. Open fractures were reported in 7.3% of fractures and neurological and vascular injuries in 1.9% and 1.5%, respectively. Conclusions: Multicenter and epidemiological studies are needed to adequately assess orthopedic fractures in Jordan so that we can establish guidelines for fracture prevention and treatment.

Palaeobiological inferences for the South American dicraeosaurid Brachytrachelopan mesai (Dinosauria; Sauropoda) based on bone histology of the holotype

ABSTRACT Brachytrachelopan is a dicraeosaurid sauropod that comes from the Jurassic of Argentine Patagonia. With the purpose to infer different palaeobiological traits (e.g., ontogenetic stage, growth dynamics, temporal correlation between morphological and anatomical parameters of maturation), we perform an osteohistological study on different postcranial elements from the holotype individual, including axial (i.e., cervical hemispinous process, dorsal ribs) and appendicular (i.e., femur) bones. The absence of a distinct external fundamental system indicates that the individual died before full body size achievement (i.e., somatic maturity). Furthermore, although not conclusive, the histological data suggest that despite its body size, which is comparable with fully grown individuals of other dicraeosaurid taxa, the individual also corresponds to a sexually immature specimen. Predominance of highly vascularised fibrolamelar with only a cyclical growth mark (CGM) in the outer cortex of the femur reveals a sustained, accelerated growth, typical feature of neosauropod dinosaurs. The external anatomy (i.e., neurocentral sutures are visible in presacral vertebrae) is consistent with histological data, since both indicate some degree of immaturity. Dorsal ribs are best elements to estimate age. The new evidence reinforces the hypothesis that mechanical forces were higher in the anterior edge of cervical hemispinous processes, although, these findings do not support the presence of horn cores or interspinous ligament system in the neck of Brachytrachelopan.

The feasibility of virtual reality for anatomic training during temporal bone dissection course

Introduction: In recent decades, the lack of educational resources for cadaveric dissections has complicated the hands-on otological surgical training of otorhinolaryngology residents due to the poor availability of cadaver temporal bones, facilities, and limited hours for practice. Since students must gain adequate and patient-safe surgical skills, novel training methods need to be considered. In this proof-of-concept study, a new virtual reality (VR) software is described; this was used during a national temporal bone dissection course where we investigated its feasibility for otological surgical training.Methods: A total of 11 otorhinolaryngology residents attended the annual 2-day hands-on temporal bone dissection course; they were divided into two groups with similar experience levels. Both groups received a lecture on temporal bone anatomy. A total of 22 cadaver temporal bones were harvested for the course; 11 of these bones were imaged by computed tomography. VR software designed for preoperative planning was then used to create 3D models of the imaged temporal bones. Prior to dissection training, the first group underwent a 30-min VR session, where they identified 24 surgically relevant anatomical landmarks on their individual temporal bone. The second group proceeded directly to dissection training. On the second day, the groups were switched. The feasibility of VR training was assessed with three different metrics: surgical performance evaluation using a modified Hopkins objective structured assessment of technical skill (OSATS), time for the surgical exposure of anatomical landmarks, and the user experience collected with a Likert scale questionnaire.Results: No differences were noted in the overall performance between the groups. However, participants with prior VR training had a lower mean time for surgical exposure of anatomical landmarks (antrum 22.09 vs. 27.64 min, p = 0.33; incus 60.00 vs. 76.00, p = 0.03; PSCC 71.83 vs. 88.50, p = 0.17) during dissection training. The participants considered VR beneficial for anatomy teaching, surgery planning, and training.Conclusion: This study demonstrated the feasibility of implementing VR training in a temporal bone dissection course. The VR training demonstrated that even short expert-guided VR sessions are beneficial, and VR training prior to the dissections has a positive effect on the time needed to perform surgical tasks while maintaining comparable performance scores.

Domestic donkey (Equus asinus asinus) at Gonur Depe and its distribution in the Ancient East

The domestic donkey (Equus asinus asinus) is a hardy, versatile working animal. This species still plays an important role in the traditional economy of the peoples of Central Asia and adjacent regions. At the same time, very little is known about the ways in which this domestic species appeared in the region and the nature of its use in the early historical epochs. The morphological features of ancient donkeys are also poorly studied. It is as-sumed that donkeys appear in the Middle East in the 4th millennium BC. Zooarchaeological data shows that the ancient population of Turkmenistan did not breed the donkey until the Late Bronze Age. Equid bones found at Chalcolithic, Early and Middle Bronze Age sites belong to the onager (Equus hemionus). Donkey bones first ap-peared in the materials from the excavations of the sites of the Bactria-Margiana Archaeological Culture (BMAC). One of the most famous site of BMAC is Gonur Depe, the administrative and ceremonial center of ancient Margi-ana. It is located in the ancient delta of the Murghab River. Gonur Depe dates from 2500 till 1500 BC. The protourban center includes two main sites — North and South Gonur. During the excavation at Gonur, 142 indi-vidual bones and 9 complete skeletons of the domestic donkey were found. Perhaps the isolated donkey bones fell into the trash layers during the destruction of the ritual objects. No traces of purposeful slaughter of these animals and consumption of their meat were found. The donkey skeletons were found inside the human burials or in associated structures, although there are independent burials of these animals as well. So, for example, at the area 8, the donkey, surrounded by ceramic vessels was placed in a tomb made of adobe bricks. In the burials 3200 and 3900, the skeletons of donkeys were found alongside the skeletons of double-humped camels and re-mains of four-wheeled wagons. In total, 4 burials with carts were found at Gonur, where the skeletons of camels are always present, whereas only in two of them — the skeletons of donkeys. It is possible that the bulls and camels were main draft animals of the Gonur people, while the donkeys mainly played the role of a pack and rid-ing animals. The height at the withers of the Gonur donkeys, reconstructed on the basis of measurements of the complete skeletons, was 115–120 cms. These were animals of average size for their species.

Experimental study on the effect of selected sterilization methods on mechanical properties of polylactide FFF specimens

PurposeBiodegradable polymers are widely used in personalized medical devices or scaffolds for tissue engineering. The manufacturing process should be finished with sterilization procedure. However, it is not clear how the different sterilization methods have an impact on the mechanical strength of the three-dimensional (3D)-printed parts, such as bone models or personalized mechanical devices. This paper aims to present the results of mechanical testing of polylactide-based bone models before and after sterilization.Design/methodology/approachPolylactide specimens prepared in fused filament fabrication technology were sterilized with different sterilization methods: ultraviolet (UV) and ethylene oxide. Mechanical properties were determined by testing tensile strength, Young’s modulus and toughness.FindingsThe tensile strength of material after sterilization was significantly higher after ethylene oxide sterilization compared to the UV sterilization, but in both sterilization methods, the specimens characterized lower tensile strength and Young’s modulus when compared to the control. In comparison of toughness results, there was no statistically significant differences. The findings are particularly significant in the perspective of using individual implants, bone grafts and dental guides.Originality/valueAlthough fused filament fabrication (FFF) 3D printing devices equipped with UV light sterilization options are available, experimental results of the effect of selected sterilization methods on the mechanical strength of additively manufactured parts have not been described. This paper completes the present state of the art on the problem of sterilization of FFF parts from biodegradable materials.

Giant cell tumor of bone: Epidemiological profile (fifth version) – A study protocol

The giant cell tumor of bone (GCTB) represents approximately 5% of primary bone tumors, and more than half of cases affect individuals between 20 and 50 years of age. Despite being a benign neoplasm, 3 to 5% of cases may show pulmonary metastases, besides it has high potential for bone destruction at the main site of the lesion, often in the epiphyses of long bones, which may lead to serious functional problems in affected patients. Multidisciplinary treatment of GCTB has been a cause for discussion in the last decade due to the discovery of drugs such as denosumab that prevent tumor progression and may be useful in cases of patients with local recurrences and unresectable tumors. The therapeutic basis of GCTB remains the isolated surgical treatment by intralesional (with adjuvants), marginal or wide resection. Intralesional treatment presents higher rates of recurrence, however it preserves the adjacent joint function and much of the individual bone stock. Resection with wide margins presents lower recurrence rates but has shown worse functional results and frequent complications in bone reconstructions. Current knowledge of GCTB surgical outcomes has been based on major world series - there is a lack of Brazilian epidemiological and surgical data on this specific type of neoplasm, except for a few series of cases. The primary objective of this paper is to identify the epidemiological profile of GCTB; the secondary objectives are to describe the surgical aspects in the main diagnostic centers and treatment of bone tumors, to analyze the clinical and surgical aspects of patients with GCTB of wrist and hand, and to analyze the clinical and surgical aspects of patients with knee GCTB. These findings may help in the maintenance or change of national guidelines for the treatment of GCTB. This study protocol was submitted to ethical assessment under the CAAE (Ethical Appreciation Presentation Certificate) registry No. 94280918.0.0000.5327 (5th version), evaluated through the substantiated opinion No. 4.770.705, and approved by the Institutional Research Ethics Committee on June 12, 2022.

Simulation of loads created by a dental bridge prosthesis based on maxilla implants

The study aims to assess the primary stability of the prosthetics on 8 implants for edentu-lous maxilla. Cases of individual implants failure and different bone mineralization are considered. The model of the maxilla was made in accordance with the three-dimensional tomographic image. Modeling of primary stability failure of implants under the influence of various loading cases were carried out. Bone materials were assumed to be isotropic, but normal and critical bone mineralization were considered. The problems were solved using the finite element method. The Coulomb-Mohr strength criterion was used to assess the primary stability. Critical prosthetics scenarios depending on the implants failure configuration and degree of bone mineralization are indicated on the basis of criterion. The most critical schemes of implant failure in the distal region for any type of mineralization with unilateral chewing load. The considered configuration of the prosthesis on 8 implants increases the risk of damage the cortical bone with age, even when all implants have survived.

Variation of the human skull bone thickness with the age, gender, and body stature: an autopsy study of the Sri Lankan population

<strong><em>Introduction: </em></strong>Many characteristics of the skull bones used in identification are subjective. Since the human skull thickness (HST) can be used as a more objective criterion, it can be used in more accurate identification in forensic anthropology, and according to literature; no such studies were conducted in Sri Lanka. The aim of this study is to assess the thickness of individual skull bones and the association of the HST with age, gender, and body stature. <strong><em>Methods:</em></strong> A cross-sectional analytical study was carried out among 100 autopsies selected randomly at the National Hospital Kandy, and Teaching Hospital Peradeniya, Sri Lanka. Socio-demographic profile was collected using an interviewer-administered questionnaire; bone thickness was measured using a calibrated vernier caliper and body height was measured using a measuring tape.<em> </em>The association between the bone thickness with age and body stature was assessed using the Pearson linear correlation. The association of bone thickness with gender was calculated with Chi-square. <em></em> <strong><em>Results:</em></strong> The mean skull bone thicknesses obtained were temporal (4.7mm on both), parietal (6.1mm on right and 5.8mm on left), occipital (7.2mm on right and 6.4mm on left), and frontal (8.8mm), with the frontal bone being the thickest among both males and females. Skull bone thickness showed a significant difference with gender in occipital and frontal bones. Only the left temporal bone thickness showed a small positive correlation with age. HST showed no correlation with body stature.<em></em> <strong><em>Conclusion: </em></strong>This study shows that there are variations in HST with gender and no correlation with body stature.

The postcranial skeleton of the gliding reptile Coelurosauravus elivensis Piveteau, 1926 (Diapsida, Weigeltisauridae) from the late Permian Of Madagascar

ABSTRACT The postcranial skeleton of the gliding neodiapsid reptile Coelurosauravus elivensis (Lower Sakamena Formation, ?upper Permian, southwestern Madagascar) is re-described in detail based on all previously referred specimens. The exquisite preservation of the material provides three-dimensional details of the individual bones, which are missing in the Laurasian weigeltisaurid material. A new skeletal reconstruction of C. elivensis is proposed including the first reconstruction of a weigeltisaurid reptile in lateral view. The re-examination of the material highlights interspecific differences in the postcranium of weigeltisaurids, in particular in the trunk and patagial spars. These animals have long been considered as arboreal and gliding reptiles. However, new information on the postcranium of C. elivensis reveals strong similarities with both extant and extinct quadrupeds specialized for a clinging arboreal lifestyle. Additionally, the presence of an additional phalanx in the fifth digit of the manus is now attested for all weigeltisaurids where this region is preserved. We suggest that this morphology could have allowed weigeltisaurids to grasp their patagium as observed in the extant gliding agamid Draco. Weigeltisaurids are thus the earliest known gliding vertebrates and some of the first tetrapods with an obligatory arboreal lifestyle, but also represent the only known vertebrates with a hyperphalangy aligned with a gliding apparatus.

Radiological and pathochemical characteristics of osteoporosis process in rabbits

Various bone and joint pathology is quite common among companion animals, a significant risk factor for which is considered to be a violation of bone metabolism. The aim of the work is to determine radiological and pathochemical criteria in the dynamics of osteoporosis process in the model of rabbits. The experimental (n = 18) and control (n = 9) groups of animals were formed. Experimental osteoporosis in rabbits of the experimental group was caused by the administration of 0.4% solution of dexamethasone (4 mg / ml) (KRKA, Slovenia) for the 21st day at a dose of 1.2 mg / kg body weight 1 time / day. Control animals were injected with saline. Blood samples for biochemical studies were taken before the induction of osteoporosis and on the 7th, 14th, 21st day. Serum levels of total calcium (Ca) and phosphorus, activity of total alkaline phosphatase and its bone isoenzyme, tartrate-resistant acid phosphatase were determined. Measurements were performed with a spectrophotometer Stat Fax 4500. X-ray examinations were performed on an X-ray machine RUM-20 before the induction of osteoporosis and on the 7th, 14th, 21st day of the study. On the 14th day of the study, some areas of the spongy substance of the proximal femur have the appearance of a large-loop pattern due to the resorption of individual bone beams. There is also an expansion of the bone marrow canal due to bone resorption, thinning and emphasizing the edges of the cortical layer. On the 21st day, changes characteristic of osteoporosis were observed - low intensity of X-ray contrast shadow of bone, significant thinning of bone structure. Radiographically established changes in bone tissue correlate with biochemical parameters of rabbit blood. On the 21st day of osteoporosis induction in experimental animals, the level of total Ca decreased 2.1 times (p &lt;0.001), and inorganic P increased 1.8 times (p &lt;0.001), compared with normal and control animals. The level of total alkaline phosphatase and bone isoenzyme alkaline phosphatase on the 21st day of the study exceeded the performance of clinically healthy and control animals 1.1 times (p &lt;0.001). The activity of tartrate-resistant acid phosphatase increased dynamically and on the 14th day was 30.7 ± 0.36 units / l, which is 1.1 times (p &lt;0.001) higher than its level in clinically healthy animals, and 21st day - 1.2 times (p &lt;0.001), respectively. The corticosteroid model of osteoporosis causes the manifestation of its radiological signs on the 14th day after induction, accompanied by hypocalcemia, hyperphosphatemia with a decrease in Ca:P and increased activity of alkaline and tartrate-resistant acid phosphatases. The complete pathochemical phase of osteoporosis occurs on the 21st day, which is manifested by a significant decrease in the ratio of phosphatases. Key words: secondary osteoporosis, bone fractures, corticosteroids, dexamethasone, compact and spongy bone tissue, rabbits.

Recognition and Segmentation of Individual Bone Fragments with a Deep Learning Approach in CT Scans of Complex Intertrochanteric Fractures: A Retrospective Study.

The characteristics of bone fragments are the main influencing factors for the choice of treatment in intertrochanteric fractures. This study aimed to develop a deep learning algorithm for recognizing and segmenting individual fragments in CT images of complex intertrochanteric fractures for orthopedic surgeons. This study was based on 160 hip CT scans (43,510 images) of complex fractures of three types based on the Evans-Jensen classification (40 cases of type 3 (IIA) fractures, 80 cases of type 4 (IIB)fractures, and 40 cases of type 5 (III)fractures) retrospectively. The images were randomly split into two groups to construct a training set of 120 CT scans (32,045 images) and a testing set of 40 CT scans (11,465 images). A deep learning model was built into a cascaded architecture composed by a convolutional neural network (CNN) for location of the fracture ROI and another CNN for recognition and segmentation of individual fragments within the ROI. The accuracy of object detection and dice coefficient of segmentation of individual fragments were used to evaluate model performance. The model yielded an average accuracy of 89.4% for individual fragment recognition and an average dice coefficient of 90.5% for segmentation in CT images. The results demonstrated the feasibility of recognition and segmentation of individual fragments in complex intertrochanteric fractures with a deep learning approach. Altogether, these promising results suggest the potential of our model to be applied to many clinical scenarios.