How to make a digital reconstruction of the human ribcage.

Up to now, there have been no publication standardizing the digital reconstruction of the modern human ribcage from commingled costo-vertebral material. Consequently, we designed a validated protocol based on anatomical features observed in the literature and the CT scanned ribcages of 10 adult European individuals. After quantifying the shape of these ribcages using 3D geometric morphometrics, we split each vertebra and rib within their corresponding (semi)landmarks. Subsequently, individual bones + (semi)landmarks were imported to LhpFusionBox, commingled and 3D reconstructed. To validate the accuracy of the protocol, we first reconstructed a randomly chosen ribcage three times and then compared these reconstructions to the rest of the sample. Since these reconstructions were closer to their original counterpart than to the others, the remaining sample was reconstructed once. Next, we tested the intra-observer error during reconstructing using the Procrustes distances among the original ribcages and the reconstructions. We observed that first each ribcage reconstruction was clustered to its original counterpart and second there was a learning curve showing an improvement in the reconstruction process over time. Subsequently, we explored general size and shape differences among the original and reconstructed ribcages through a study of centroid size and a permutation test on the Procrustes distances (10,000 permutations), respectively. Specific shape differences between both groups were further examined through a principal component analysis in shape space. None of these analyses found statistical differences between the original and reconstructed ribcages (p > 0.05). Eventually, we extracted the mean shapes of the original ribcages and the reconstructions in order to visualize potential deviations caused by the anatomical considerations of the researcher. These results demonstrate that the protocol is accurate enough to be used when reconstructing a disarticulated human ribcage.

Determination of the value of vertebral heart size regarding the weight and body area in canines / Determinação dos valores do vertebral heart size em relação ao peso e área corporal canina

The vertebral heart size is a method used to measure the cardiac dimension in order to identify the remodeling of the chambres in heart disease. This study aims to determinate the vertebral heart size values at right lateral and ventrodorsal radiographs views relating to canines weight and body area variations. For the purpose of the study 40 healthy dogs within the age of 1 to 6 years, males and females, with deep or intermediated thorax were selected, brachycephalic dogs were not included in the study; the dogs were separated in four groups: group 1(n=9) compound of dogs up to 5 kg; group 2 (n=8) with dogs from 5,1 to 10 kg; group 3 (n=12) with dogs from 10,1 to19 kg and group 4 (n=11) with dogs weighing more than 19,1 kg. The values of body score, body mass index and the thorax configuration where previously measured, as well as the vertebral heart size and the depth width ratio from the radiographs. The results demonstrated intervals of right lateral-lateral vertebral heart size 9.9 to 10.4v and ventro-dorsal vertebral heart size of 9.8-10.3v. The study results show that the vertebral heart size numbers did not correlate with weight or body area, regardless the type of radiography view. Therefore, it can be concluded that the vertebral heart size in right lateral and ventrodorsal radiography can be used to rate the cardiac area, not suffering influence by the dog's weight or body area.

O vertebral heart size é um método utilizado para mensurar a dimensão cardíaca visando identificar os remodelamentos das câmaras nas cardiopatias. O objetivo do estudo foi determinar os valores de vertebral heart size nas projeções radiográficas latero-lateral direita e ventro-dorsal conforme as variações do peso e área corporal. Para isso, foram selecionados 40 cães hígidos com idade entre 1 e 6 anos, machos e fêmeas, com padrão torácico intermediário e profundo, com exclusão dos braquicefálicos; os cães foram divididos em quatro grupos: grupo 1 (n=9) composto por cães de até 5 kg; grupo 2 (n=8) com cães de 5,1 a 10 kg; grupo 3 (n=12) com cães de 10,1 a 19 kg e grupo 4 (n=11) com cães acima de 19,1 kg. Os valores de escore corporal, índice de massa corporal e conformação torácica foram previamente mensurados, bem como os valores dos vertebral heart size a relação profundidade/largura torácica das radiografias. Os resultados demonstraram intervalos de vertebral heart size latero-lateral 9.9 a 10.4v e vertebral heart size ventro dorsal de 9.8-10.3v. Os valores não apresentaram correlação com o peso e área corporal nos grupos estudados, independente das projeções estudas. Assim, pode-se concluir que método vertebral heart size nas projeções estudadas é aplicável na avaliação da área cardíaca, não sofrendo influências do peso e área corporal canina.

Utility of thoracic cage width in assessing surgical difficulty of minimally invasive esophagectomy in left lateral decubitus position.

BACKGROUND: This study aimed to assess the surgical difficulty of minimally invasive esophagectomy in the left lateral decubitus position for patients with esophageal cancer from the perspective of short-term outcomes, including operation time, blood loss, and morbidity. MATERIALS AND METHODS: The initial 44 consecutive patients with esophageal cancer who underwent minimally invasive esophagectomy were statistically analyzed retrospectively. Thoracic cage area was measured from preoperative computed tomography as a factor affecting the surgical difficulty of minimally invasive esophagectomy, as well as other patient characteristics. Correlations with short-term outcomes including chest operation time, blood loss, and morbidity rate were then examined. RESULTS: In univariate analyses, smaller area of the upper thoracic cage width correlated with prolonged thoracic procedure time (p = 0.0119) and greater blood loss during thoracic procedures (p = 0.0283), but area of the lower thoracic cage showed no correlations. History of respiratory disease was associated with thoracic procedure time (p < 0.0001), but not blood loss. In multivariate analysis, small area of the upper thoracic cage was independently associated with prolonged thoracic procedure time (p = 0.0253). Small upper thoracic cage area was not directly correlated with morbidity rate, but prolonged thoracic procedure time was associated with increased blood loss (p < 0.0001) and morbidity rate (p = 0.0204). Empirical time reduction (p = 0.0065), but not blood loss, was associated with thoracic procedure time. However, area of the upper thoracic cage did not correlate with empirical case number. In multivariate analysis, area of the upper thoracic cage (p = 0.0317) and empirical case number (p = 0.0193) correlated independently with thoracic procedure time. CONCLUSION: A small area of the upper thoracic cage correlated significantly with prolonged thoracic procedure time and increased thoracic blood loss for minimally invasive esophagectomy in the left lateral decubitus position, suggesting the surgical difficulty of minimally invasive esophagectomy in the left lateral decubitus position.

Trunk Growth in Early-Onset Idiopathic Scoliosis Measured With Biplanar Radiography.

STUDY DESIGN: Cross-sectional and longitudinal retrospective study. OBJECTIVES: To measure thoracic dimensions and volume during growth in early-onset idiopathic scoliosis (EOIS) patients and to compare them to a population of asymptomatic adults and to the previous literature. SUMMARY OF BACKGROUND DATA: Data on trunk growth for scoliotic children between 6 and 14 years of age is sparse in the literature. METHODS: Thirty-six patients (29 girls and 7 boys, between 3 and 14 years old, average Cobb angle 33°±15°) were included, all with a minimum two-year follow-up. Sixty-one asymptomatic girls and 54 asymptomatic adults were included as control groups. All subjects underwent biplanar radiography and 3D reconstruction of the spine, pelvis, and rib cage. EOIS patients repeated their radiologic examination every six months. Cobb angle, rib cage volume, anteroposterior and transverse diameters, thoracic index, thoracic perimeter, pelvic incidence, and T1-T12 and T1-S1 distance were calculated. Reproducibility of measurement was assessed. RESULTS: Measurement reliability in such young patients was comparable to previous studies in adolescents and adults. Geometrical parameters of EOIS patients increased linearly with age. For instance, rib cage volume in girls with EOIS increased from 2200 cm3 at six to seven years of age to 4100 cm3 at 13-14 years (65% of adult values, 294 cm3/y). Comparison with asymptomatic girls showed that EOIS could affect growth spurt. Longitudinal analysis on a cohort of six girls who had a follow-up of six years confirmed the cross-sectional data. CONCLUSIONS: In this longitudinal and cross-sectional study, trunk growth between 3 and 14 years of age was characterized, for the first time, with biplanar radiography and 3D reconstruction. The results can be useful to estimate patient growth and thus have potential application in the surgical planning of EOIS patients. LEVEL OF EVIDENCE: Level II, retrospective study.

Three-dimensional analysis of sexual dimorphism in ribcage kinematics of modern humans.

OBJECTIVES: Sexual dimorphism is an important biological factor underlying morphological variation in the human skeleton. Previous research found sex-related differences in the static ribcage, with males having more horizontally oriented ribs and a wider lower ribcage than females. Furthermore, a recent study found sex-related differences in the kinematics of the human lungs, with cranio-caudal movements of the caudal part of the lungs accounting for most of the differences between sexes. However, these movements cannot be quantified in the skeletal ribcage, so we do not know if the differences observed in the lungs are also reflected in sex differences in the motion of the skeletal thorax. MATERIALS AND METHODS: To address this issue, we quantified the morphological variation of 42 contemporary human ribcages (sex-balanced) in both maximal inspiration and expiration using 526 landmarks and semilandmarks. Thoracic centroid size differences between sexes were assessed using a t test, and shape differences were assessed using Procrustes shape coordinates, through mean comparisons and dummy regressions of shape on kinematic status. A principal components analysis was used to explore the full range of morphological variation. RESULTS: Our results show significant size differences between males and females both in inspiration and expiration (p < .01) as well as significant shape differences, with males deforming more than females during inspiration, especially in the mediolateral dimension of the lower ribcage. Finally, dummy regressions of shape on kinematic status showed a small but statistically significant difference in vectors of breathing kinematics between males and females (14.78°; p < .01). DISCUSSION: We support that sex-related differences in skeletal ribcage kinematics are discernible, even when soft tissues are not analyzed. We hypothesize that this differential breathing pattern is primarily a result of more pronounced diaphragmatic breathing in males, which might relate to differences in body composition, metabolism, and ultimately greater oxygen demand in males compared to females. Future research should further explore the links between ribcage morphological variation and basal metabolic rate.

Three-dimensional printed models of the rib cage in children with non-accidental injury as an effective visual-aid tool.

Three-dimensional (3-D) printing is gaining terrain in medical education, presurgical evaluation and recently as forensic evidence in court. Physicians, including radiologists, often provide expert testimony in court cases involving children with rib fractures and other injuries concerning for child physical abuse. Effectively communicating the complexities of fractures and other skeletal findings to nonmedical personnel using standard radiology studies can be challenging, especially during medical courtroom testimony. For this reason, we printed two 3-D models of the rib cage from the chest computed tomography (CT) scans of two patients with suspected non-accidental injury. The patients also had available chest radiographs. The DICOM (Digital Imaging and Communications in Medicine) data were 3-D reconstructed and segmented using two attenuation thresholds. We removed unwanted structures and printed them on a commercially available scanner. A pediatric radiologist, blinded to clinical data, reviewed both 3-D models, identified all rib lesions and classified them according to their healing stage. We compared the 3-D models and the chest radiograph against the chest CT as the standard of care. We convened a meeting with the Child Protection Team at out institution to get their feedback and opinions about the models. From our observations of our experts, three spontaneous interactions were observed. Instinctively, the experts picked up and grasped the models, rotating them, feeling them and angling them to better visualize the fractures from multiple angles. The experts expressed a willingness to consider using the models in court.

Standard and viscoelastic mechanical properties of respiratory system compartments in dogs: Effect of volume, posture, and shape.

In 9 anesthetized, paralyzed dogs lung and chest-wall standard (viscous resistance, Rint, and quasi-static elastance, Est) and viscoelastic parameters (resistance, Rvel, and time constant, τvel) were measured in the supine posture before and after rib-cage block, after application of an expiratory threshold load, and after 75° head-up tilting before and after wide chest opening. Lung and chest-wall τvel were the same under all conditions. Rvel was independent of volume and posture, and greater for the lung. Chest-wall Rint was independent of flow, volume, and posture. Lung Rint decreased with increasing volume. Chest-wall Rint, Est and Rvel increased with rib-cage block, allowing the assessment of both abdominal-wall and rib-cage characteristics. When chest opening did not elicit bronchoconstriction, the decrease of Rvel was ∼6%. Main conclusions: lung and chest-wall exhibit linear tissue viscoelasticity within the range studied; rib-cage and abdomen characteristics are similar, and asynchronous motion is not expected at physiological respiratory rates; in normal lungs, heterogeneity of parallel time constants plays a marginal role.

Traumatic thoracic rib cage hernias: Operative management and proposal for a new anatomic-based grading system.

BACKGROUND: Traumatic Rib Cage Hernias (TRCH) requiring operative repair are rare and there is currently no literature to guiding surgical management. METHODS: Perioperative review of TRCH over 32 years. Five operative grades were developed based on extent of tissue/bone damage, size, and location. RESULTS: Twenty-four patients (20 blunt, 4 penetrating) underwent operative repair. Lung was the herniated organ in 88% with a median of 4 rib fractures and average size of 60.25 cm. Types of operation were well clustered by assigned TRCH grade. The majority required mesh (75%) and/or rib plating (79%). Complex tissue flap reconstruction was required in 10%. Full range-of-motion was maintained in 88% with79% returning to pre-injury activity levels. Five patients had continued pain at final follow up (mean = 7months). CONCLUSION: The size and degree of injury has important implications in the optimal surgical management of TRCHs. These operative grades effectively direct surgical care for these rare and complex injuries.

Morfometria do osso esterno e sua correlação com o volume pulmonar / Sternum bone morphology and its correlation with lung volume

Este estudo teve por objetivo desenvolver um modelo matemático que a partir da extensão do osso esterno fornecesse o tamanho do pulmão compatível para o receptor. Foram coletadas as medidas antropométricas do tórax de 250 indivíduos, através de exame de tomografia computadorizada. Os resultados apontam que a medida do osso esterno (distância da incisura jugular até processo xifóide) apresenta correlação positiva com todas as outras medidas do tórax (medida ântero-posterior e látero-medial entre II e III costela, e ápice à base de ambos os pulmões). Entretanto, o volume pulmonar e sua relação com o osso esterno apresentam discrepâncias quando analisados sob a correlação de Pearson, pois a relação entre a medida da incisura jugular ao processo xifóide e a medida do ápice à base do pulmão direito e esquerdo, apresenta correlação positiva média (0,31-0,6). Já a medida da incisura jugular ao processo xifóide com a medida ântero-posterior e látero-medial do tórax, apresenta correlação significativa baixa (0-0,3). Então, a análise estatística da correlação de Pearson demonstrou ser inviável o desenvolvimento da fórmula, pois esta não seria confiável já que funcionaria para cerca de apenas 39% dos pacientes. Assim, o melhor método para determinar o doador para o transplante, continua sendo a análise de fatores de risco, a capacidade vital forçada do doador e receptor com estatura maior do que a do doador.

This study aimed at developing a mathematical model that can provide the compatible lung size for the recipient from the length of the sternum bone. Anthropometric chest measurements of 250 individuals were collected through a CT scan. The results indicate that the measurement of the sternum bone (distance from the jugular notch to the xiphoid process) shows a positive correlation with all other thorax measurements (antero-posterior and medial-posterior measurement between ribs II and III, and apex-to-base on both lungs). However, lung volume and its correlation to the sternal bone present discrepancies when analyzed under Pearson's correlation, since the relation between the jugular notch measurement and the apex measurement at the base of the right and left lungs shows a positive correlation mean (0.31-0.6). The measurement of the jugular notch in the xiphoid process with the anterior-posterior and medial-medial measurements, presents a low significant correlation (0-0.3). Therefore, the statistical analysis of the Pearson's correlation showed that the formula could not be applied since it would not be reliable since it would work for only 39% of the patients. Thus, the best method to determine the donor for transplantation remains the analysis of risk factors, the forced vital capacity of the donor, and the recipient being taller than the donor.

Cardiothoracic Ratio and All-Cause Mortality and Cardiovascular Disease Events in Hemodialysis Patients: The Q-Cohort Study.

BACKGROUND: Cardiothoracic ratio by chest radiography is commonly used to assess volume status. Little is known about the relationships between cardiothoracic ratio and the incidence of clinical outcomes in patients undergoing hemodialysis (HD). STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: 3,436 participants in the Q-Cohort Study 18 years or older who underwent maintenance HD in Japan. PREDICTOR: Cardiothoracic ratio. OUTCOMES & MEASUREMENTS: All-cause mortality and cardiovascular disease (CVD) events. RESULTS: During a 4-year follow-up period, 564 (16.4%) patients died of any cause and 590 (17.2%) developed CVD events. From baseline cardiothoracic ratios, participants were categorized into sex-specific quartiles because cardiothoracic ratio distribution differed by sex. The 4-year event-free survival rate, in terms of all-cause mortality and CVD events, was significantly lower with higher cardiothoracic ratios. Compared to the lowest cardiothoracic ratio (quartile 1), multivariable-adjusted HRs for all-cause mortality were 0.89 (95% CI, 0.66-1.20), 1.41 (1.08-1.86), and 1.52 (1.17-2.00) in patients from quartiles 2, 3, and 4, respectively. Similarly, in comparison to quartile 1, multivariable-adjusted HRs for CVD events were 1.00 (95% CI, 0.77-1.31), 1.18 (0.92-1.53), and 1.37 (1.07-1.76) in patients from quartiles 2, 3, and 4, respectively. Furthermore, the combination of higher cardiothoracic ratio and normohypotension (systolic blood pressure < 140mmHg and diastolic blood pressure < 90mmHg) was associated with higher risk for CVD events. LIMITATIONS: Single measurement of all variables, potentially less-heterogeneous patient population, and limited ascertainment of cardiac parameters and the outcomes. CONCLUSIONS: Higher cardiothoracic ratio is associated with higher risk for both all-cause mortality and CVD events in patients undergoing HD.

A parametric ribcage geometry model accounting for variations among the adult population.

The objective of this study is to develop a parametric ribcage model that can account for morphological variations among the adult population. Ribcage geometries, including 12 pair of ribs, sternum, and thoracic spine, were collected from CT scans of 101 adult subjects through image segmentation, landmark identification (1016 for each subject), symmetry adjustment, and template mesh mapping (26,180 elements for each subject). Generalized procrustes analysis (GPA), principal component analysis (PCA), and regression analysis were used to develop a parametric ribcage model, which can predict nodal locations of the template mesh according to age, sex, height, and body mass index (BMI). Two regression models, a quadratic model for estimating the ribcage size and a linear model for estimating the ribcage shape, were developed. The results showed that the ribcage size was dominated by the height (p=0.000) and age-sex-interaction (p=0.007) and the ribcage shape was significantly affected by the age (p=0.0005), sex (p=0.0002), height (p=0.0064) and BMI (p=0.0000). Along with proper assignment of cortical bone thickness, material properties and failure properties, this parametric ribcage model can directly serve as the mesh of finite element ribcage models for quantifying effects of human characteristics on thoracic injury risks.