Микроструктурна адаптација коштаног ткива фацијалног скелета на дистрибуцију оклузалног оптерећења код особа са пуним зубним низом и њена улога у настанку прелома фацијалног скелета

Occlusal forces have traditionally been explained to transfer through the facial skeleton along specific osseous trajectories known as buttresses. These regions were assumed as zones of strength due to their thick cortical bone structure, while the areas between the buttresses containing thin cortical bone were considered weak and fragile. However, recent studies revealed that both cortical and trabecular bone of the mid-facial skeleton of dentulous individuals exhibit remarkable regional variations in structure and elastic properties. These variations have been frequently suggested to result from the different involvement of cortical and trabecular bone in the transfer of occlusal forces, although there has been no study to link bone microarchitecture to the occlusal loading. Moreover, although the classical concept of buttresses has been extensively studied by mechanical methods, such as finite element (FE) analysis, there is still no direct evidence for occlusal load distribution through the cortical and trabecular bone compartments individually. Additionally, relatively less scientific attention has been paid to the investigation of bone structure along Le Fort fracture lines that have traditionally been assumed as weak areas at which the mid-facial skeleton commonly fractures after injury. Papers published so far in this field focused mainly on the epidemiology and the role of injury mechanism in the fracture development, without considering the structural basis of increased bone fragility along the Le Fort fracture lines...Према традиционалном објашњeњу, пренос оклузалног оптерећења кроз кости лица током жвакања обавља се дуж специфичних путања унутар кости званих трајекторије или „батреси“. Ови делови костију лица сматрани су јаким зонама јер их изграђује кортикална кост велике дебљине, док су делови кости смештени између трајекторија сматрани слабим и фрагилним због њихове танке кортикалне грађе. Међутим, недавним истраживањима је откривено да и кортикална и трабекуларна кост средњег масива лица код особа са пуним зубним низом показују значајне регионалне варијације у грађи и еластичним својствима. Ове се варијације често сматрају адаптацијом кортикалне и трабекуларне кости на различито оптерећење у преносу оклузалних сила током жвакања, иако повезаност микроархитектуре кости и оклузалног оптерећења до сада није испитивана код људи. Штавише, иако је класични концепт преноса оклузалног оптерећења дуж трајекторија интензивно проучаван механичким методама, као што је метод коначних елемената, још увек није испитано на који начин се оклузалне силе преносе појединачно кроз кортикалну и трабекуларну кост. Значајно мању научну пажњу је привлачило испитивање грађе костију лица дуж Le Fort линија које су традиционално сматране најчешћим местима прелома костију фацијалног скелета узрокованих механичким силама. Досадашње студије у овој области су биле фокусиране углавном на епидемиолошка истраживања и улогу механизма повреде у настанку ових прелома, док структурна основа повећане фрагилности кости дуж Le Fort линија није испитивана..

Side asymmetry in nasal resistance correlate with nasal obstruction severity in patients with septal deformities: Computational fluid dynamics study

Objectives The objective of this study was to investigate the relationship between side asymmetry in nasal resistance (NR) and severity of the nasal airway obstruction (NAO) in patients with different types of nasal septal deformity (NSD). Design Computational fluid dynamics (CFD) study. Setting The study was conducted in a tertiary medical centre. Participants The study included 232 patients, who were referred to the CT examination of the paranasal sinuses. Exclusion criteria were sinonasal and respiratory diseases that may interfere with the nasal obstruction. The presence and the type of NSD were recorded according to the Mladina's classification. Main outcome measures The presence and severity of NAO in each patient were assessed by NOSE questionnaire. Eight computational models of the nasal cavity were created from CT scans. Models represented seven Mladina's NSD types and a straight septum of a symptomless patient. CFD calculated airflow partitioning and NR for each nasal passage. Side differences in NR were calculated by the equation increment NR = NRleft - NRright. The relationship between NOSE scores, airflow partitioning and side differences in NR was explored using Spearman's correlation analysis. Results Mladina's types of NSD showed differences in airflow partitioning and the degree of side asymmetry in NR. A significant positive correlation was detected between side differences in NR and NOSE scores (R = .762, P = .028). A significant negative correlation was found between the per cent of unilateral airflow and NR (R = -.524, P = .037). Conclusions Our results demonstrated that side asymmetry in NR could explain differences in NAO severity related to the NSD type.This is the peer-reviewed version of the article: Janović, N.; Cocić, A.; Stamenić, M.; Janović, A.; Đurić, M. Side Asymmetry in Nasal Resistance Correlate with Nasal Obstruction Severity in Patients with Septal Deformities: Computational Fluid Dynamics Study. Clinical Otolaryngology 2020. [https://doi.org/10.1111/coa.13563

Paranasal sinus osteoma: is there any association with anatomical variations?

Background: Developmental disturbances of the paranasal sinuses are proposed as the cause of osteoma. We examined whether such disturbances may result in the frequent presence of anatomical variations of the paranasal sinuses in patients with osteoma. Methodology/Principal: The study was performed retrospectively on 2,820 patients subjected to CT examination during 2005 - 2011. Demographic and CT characteristics of osteoma, and associated pathological findings were evaluated for 104 patients with diagnosed osteoma. The presence of anatomical variations was assessed for 51 osteoma patients with a complete medical history, and for 1,233 patients from a control group. Results: The prevalence of osteomas was found to be 3.69%, with male to female ratio 1.08:1. The frontal sinus was most commonly affected, The presence of anatomical variations was more frequent in patients with osteoma than in controls, with significant differences confirmed for the sphenomaxillary plate, infraorbital cell, and crista galli pneumatization. Conclusions: The paranasal sinus osteoma is associated with higher prevalence of anatomical variations, This can be explained either by the stronger influence of genetic and/or environmental factors on the development of the paranasal sinuses in patients with osteoma, or by their higher susceptibility to abovementioned factors

Hyoid Bone and Thyroid Cartilage Metastases from Sigmoid Colon Adenocarcinoma: A Case Report

Background: Secondary tumours of the hyoid bone and thyroid cartilage are extremely rare. In this paper, we present a case of the hyoid bone and thyroid cartilage metastases in a patient treated for sigmoid colon adenocarcinoma. Case Report: Four years after sigmoid colon adenocarcinoma was diagnosed and treated with surgery and chemotherapy, the patient developed bone metastases in the left sacroiliac joint and right proximal humerus. Although the patient did not complain of any related symptoms, in a bone scintigraphy the accumulation of Technetium-99m was incidentally detected in the two sites of the anterior neck. On ultrasound examination there were two hyperechoic and heterogeneous masses with calcifications placed in front of the hyoid bone and thyroid cartilage. Computerized tomography demonstrated massive hyoid bone and thyroid cartilage destruction. Conclusion: In patients with progressive sigmoid colon adenocarcinoma, destruction of the hyoid bone and thyroid cartilage could be suspected for metastases

Trauma of the frontal region is influenced by the volume of frontal sinuses. A finite element study

Anatomy of frontal sinuses varies individually, from differences in volume and shape to a rare case when the sinuses are absent. However, there are scarce data related to influence of these variations on impact generated fracture pattern. Therefore, the aim of this study was to analyse the influence of frontal sinus volume on the stress distribution and fracture pattern in the frontal region. The study included four representative Finite Element models of the skull. Reference model was built on the basis of computed tomography scans of a human head with normally developed frontal sinuses. By modifying the reference model, three additional models were generated: a model without sinuses, with hypoplasic, and with hyperplasic sinuses. A 7.7 kN force was applied perpendicularly to the forehead of each model, in order to simulate a frontal impact. The results demonstrated that the distribution of impact stress in frontal region depends on the frontal sinus volume. The anterior sinus wall showed the highest fragility in case with hyperplasic sinuses, whereas posterior wall/inner plate showed more fragility in cases with hypoplasic and undeveloped sinuses. Well-developed frontal sinuses might, through absorption of the impact energy by anterior wall, protect the posterior wall and intracranial contents.This work was supported in part by grants from the Serbian Ministry of Education, Science and Technological Development III45005, III41007, ON174028 and EU project FP7 ICT SIFEM 600933

Side asymmetry in nasal resistance correlate with nasal obstruction severity in patients with septal deformities: Computational fluid dynamics study

Objectives The objective of this study was to investigate the relationship between side asymmetry in nasal resistance (NR) and severity of the nasal airway obstruction (NAO) in patients with different types of nasal septal deformity (NSD). Design Computational fluid dynamics (CFD) study. Setting The study was conducted in a tertiary medical centre. Participants The study included 232 patients, who were referred to the CT examination of the paranasal sinuses. Exclusion criteria were sinonasal and respiratory diseases that may interfere with the nasal obstruction. The presence and the type of NSD were recorded according to the Mladina's classification. Main outcome measures The presence and severity of NAO in each patient were assessed by NOSE questionnaire. Eight computational models of the nasal cavity were created from CT scans. Models represented seven Mladina's NSD types and a straight septum of a symptomless patient. CFD calculated airflow partitioning and NR for each nasal passage. Side differences in NR were calculated by the equation increment NR = NRleft - NRright. The relationship between NOSE scores, airflow partitioning and side differences in NR was explored using Spearman's correlation analysis. Results Mladina's types of NSD showed differences in airflow partitioning and the degree of side asymmetry in NR. A significant positive correlation was detected between side differences in NR and NOSE scores (R = .762, P = .028). A significant negative correlation was found between the per cent of unilateral airflow and NR (R = -.524, P = .037). Conclusions Our results demonstrated that side asymmetry in NR could explain differences in NAO severity related to the NSD type.Peer-reviewed manuscript: [http://smile.stomf.bg.ac.rs/handle/123456789/2527

Side asymmetry in nasal resistance correlate with nasal obstruction severity in patients with septal deformities: Computational fluid dynamics study

Objectives The objective of this study was to investigate the relationship between side asymmetry in nasal resistance (NR) and severity of the nasal airway obstruction (NAO) in patients with different types of nasal septal deformity (NSD). Design Computational fluid dynamics (CFD) study. Setting The study was conducted in a tertiary medical centre. Participants The study included 232 patients, who were referred to the CT examination of the paranasal sinuses. Exclusion criteria were sinonasal and respiratory diseases that may interfere with the nasal obstruction. The presence and the type of NSD were recorded according to the Mladina's classification. Main outcome measures The presence and severity of NAO in each patient were assessed by NOSE questionnaire. Eight computational models of the nasal cavity were created from CT scans. Models represented seven Mladina's NSD types and a straight septum of a symptomless patient. CFD calculated airflow partitioning and NR for each nasal passage. Side differences in NR were calculated by the equation increment NR = NRleft - NRright. The relationship between NOSE scores, airflow partitioning and side differences in NR was explored using Spearman's correlation analysis. Results Mladina's types of NSD showed differences in airflow partitioning and the degree of side asymmetry in NR. A significant positive correlation was detected between side differences in NR and NOSE scores (R = .762, P = .028). A significant negative correlation was found between the per cent of unilateral airflow and NR (R = -.524, P = .037). Conclusions Our results demonstrated that side asymmetry in NR could explain differences in NAO severity related to the NSD type

Association between regional heterogeneity in the mid-facial bone micro-architecture and increased fragility along Le Fort lines

Background/AimLe Fort lines have traditionally been considered as zones of weakness in the mid-facial skeleton although the structural basis of increased bone fragility at these sites has not yet been investigated. Considering recent findings of occlusal loading-related regional heterogeneity in the mid-facial bone micro-architecture, the aim of this study was to explore whether such heterogeneity in cortical and cancellous bone micro-architecture may contribute to increased fragility at Le Fort fracture sites. Materials and MethodsTwenty-five cortical and thirteen cancellous bone specimens were harvested from a dry skull and analyzed by micro-CT. Specimens were classified into Le Fort or Non-Le Fort groups based on their location in the mid-facial skeleton. ResultsCortical bone along Le Fort lines showed tendencies toward lower thickness (1.50.63 vs 1.75 +/- 0.79; P=.39) and greater porosity (11.48 +/- 5.67 vs 10.28 +/- 5.28; P=.59). A significant difference was detected in the trabecular degree of anisotropy which was higher in cancellous bone from Le Fort fracture sites (2.14 +/- 0.69 vs 1.58 +/- 0.34; P=.02). ConclusionsRegional heterogeneity in cortical bone micro-architecture could not fully explain increased fragility of the mid-facial skeleton at the Le Fort lines. However, regional differences in trabecular bone anisotropy may contribute to increased bone fragility

Occlusal load distribution through the cortical and trabecular bone of the human mid-facial skeleton in natural dentition: A three-dimensional finite element study

Understanding of the occlusal load distribution through the mid-facial skeleton in natural dentition is essential because alterations in magnitude and/or direction of occlusal forces may cause remarkable changes in cortical and trabecular bone structure. Previous analyses by strain gauge technique, photoelastic and, more recently, finite element (FE) methods provided no direct evidence for occlusal load distribution through the cortical and trabecular bone compartments individually. Therefore, we developed an improved three-dimensional FE model of the human skull in order to clarify the distribution of occlusal forces through the cortical and trabecular bone during habitual masticatory activities. Particular focus was placed on the load transfer through the anterior and posterior maxilla. The results were presented in von Mises stress (VMS) and the maximum principal stress, and compared to the reported FE and strain gauge data. Our qualitative stress analysis indicates that occlusal forces distribute through the mid-facial skeleton along five vertical and two horizontal buttresses. We demonstrated that cortical bone has a priority in the transfer of occlusal load in the anterior maxilla, whereas both cortical and trabecular bone in the posterior maxilla are equally involved in performing this task Observed site dependence of the occlusal load distribution may help clinicians in creating strategies for implantology and orthodontic treatments. Additionally, the magnitude of VMS in our model was significantly lower in comparison to previous FE models composed only of cortical bone. This finding suggests that both cortical and trabecular bone should be modeled whenever stress will be quantitatively analyzed

Trauma of the Frontal Region Is Influenced by the Volume of Frontal Sinuses. A Finite Element Study

Anatomy of frontal sinuses varies individually, from differences in volume and shape to a rare case when the sinuses are absent. However, there are scarce data related to influence of these variations on impact generated fracture pattern. Therefore, the aim of this study was to analyse the influence of frontal sinus volume on the stress distribution and fracture pattern in the frontal region. The study included four representative Finite Element models of the skull. Reference model was built on the basis of computed tomography scans of a human head with normally developed frontal sinuses. By modifying the reference model, three additional models were generated: a model without sinuses, with hypoplasic, and with hyperplasic sinuses. A 7.7 kN force was applied perpendicularly to the forehead of each model, in order to simulate a frontal impact. The results demonstrated that the distribution of impact stress in frontal region depends on the frontal sinus volume. The anterior sinus wall showed the highest fragility in case with hyperplasic sinuses, whereas posterior wall/inner plate showed more fragility in cases with hypoplasic and undeveloped sinuses. Well-developed frontal sinuses might, through absorption of the impact energy by anterior wall, protect the posterior wall and intracranial contents