Pelvic Shape Research Articles

Gradual exacerbation of obstetric constraints during hominoid evolution implied by re-evaluation of cephalopelvic fit in chimpanzees.

Under the obstetrical dilemma hypothesis, sexual dimorphism in pelvic shape is a solution to accommodate high fetopelvic constraints. It is therefore unclear why chimpanzees display a human-like pattern of pelvic sexual dimorphism despite having easier births enabled by small neonates and capacious pelvic canals. Here we reassessed chimpanzee fetopelvic fit using three-dimensional simulations, revealing a similarly constricted midpelvis as in humans, with even narrower outlet dimensions. Geometric morphometric analyses confirm that female chimpanzees have larger pelvic canals than males despite a smaller body size and a morphology that maximizes pelvic dimensions favourable for parturition, particularly in smaller-bodied individuals. Together with evidence for increased neurological immaturity at birth relative to monkeys, our findings imply substantial obstetric constraints in chimpanzees and possibly other apes. We therefore propose that difficult birth did not arise abruptly in Homo with increasing encephalization but evolved gradually through a series of obstetric compromises from an already constricted birth canal shared across anthropoid primates. Specifically, we propose that obstetric selection pressures exacerbated incrementally with the stiffening of the symphysis that accompanied body size increase in hominoids, while subsequent adaptations to bipedalism shortened the ilium. The resulting contorted birth canal required obligatory fetal rotation, thus greatly increasing birth difficulty.

No birth-associated maternal mortality in Japanese macaques (Macaca fuscata) despite giving birth to large-headed neonates

Human fetuses at term are large relative to the dimensions of the maternal birth canal, implying that their birth can be associated with difficulties. The tight passage through the human birth canal can lead to devastating outcomes if birth becomes obstructed, including maternal and fetal death. Although macaques have to accommodate similarly large fetuses, relative to their maternal birth canals, it was not known whether macaque mothers face birth difficulties similar to humans. Based on 27 y of demographic data from a semi-free-ranging, closely monitored population of Japanese macaques (Macaca fuscata), we found no birth-associated mortality in macaques. This differs from the situation in many human populations. We suggest three nonmutually exclusive hypotheses to explain these observations. i) The macaque fetal skull is similarly flexible as the human fetal skull. ii) The macaque pelvis and connective tissue show greater flexibility during birth. iii) The interplay between macaque pelvic shape and birth dynamics is smoother and incurs fewer complications than in humans.

Bone remodeling after revision total hip arthroplasty for large acetabular defects.

Large acetabular bone defects are challenging in hip revision surgery. Clinical assessment is crucial to evaluate modern technologies in surgical reconstruction. We aimed to better understand the bone remodeling that occurs following acetabular reconstruction. Our objectives were: (1) To characterize changes in the shape of the pelvis by studying sequential computed tomography (CT) scans collected immediately and 1-year postoperatively and (2) to identify which part of the pelvis is most susceptible to remodeling. We used the CT scans taken at two timepoints, of 24 patients with acetabular bone defects classified as Paprosky IIIB, treated with three-dimensional (3D)-printed custom-made acetabular implants. Segmented 3D models of the bony pelvis were co-registered using three different techniques. A global co-registration of the full pelvis was conducted, followed by the co-registration of the innominate bone and then ilium only, on the ipsilateral reconstructed side. The relative movements of the ilium, ischium, and pubis were analyzed from visual inspection and using co-registration metrics (root mean square error and intersection over union). No bone remodeling was found in 14/24 patients (58%). The co-registration of the innominate bone indicated bone remodeling in five cases (21%), while the remaining five cases (21%) presented remodeling in the global co-registration but not the innominate bone co-registration, suggestive of changes occurring at the sacroiliac joint. Changes in the pelvic shape were greatest at the pubis and ischium. Bone remodeling may occur in complex cases of Paprosky type IIIB defects, after acetabular reconstruction (occurrence of 21%, 5/24 cases). Surgeons and engineers should consider this when monitoring implant migration.

Sex differences in pelvic size and shape in the striped field mouse from Slovakia

Morphometric analysis and evaluation of 260 striped field mice (Apodemus agrarius) were carried out to identify sexual size dimorphism in pelvic bones regarding the age of individuals and the reproductive history of females. Pelvic size was found to differ between subadult and adult individuals of both sexes. A comparison using the Mann–Whitney U test between the right and left parts of the pelvis showed statistically non-significant differences between the pelvis dimensions. In the inter-sexual comparison of both ages (subadult, adult), statistically significant differences were found for only four traits in adults: length of the coxal bone (LP1), width of the ischiopubis (WP1), length of the obturator foramen (LSF) and width of the obturator foramen (WSF). The two indices (WSF/LSF and WP1/LP2) evaluated clearly reflected changes in the pelvic shape, which were most pronounced in adult mice. For the group of subadult males and females, the differences in measured traits and indices were not as pronounced. Several analyses, such as the Mann–Whitney U test, principal component analysis (PCA) as well as discriminant analysis (DFA), showed sex differences in pelvic morphology and shape, although the two sexes overlapped. Similarly, one-way ANCOVA showed that there was a significant difference between the sexes for the adjusted means. Analyses showed that for a given body mass, it appears that females tend to have larger pelvises. Thus, the sexual dimorphism of females was related to pelvic size and shape in A. agrarius. The breeding history showed differences in pelvic dimensions in following direction: the nulliparous < primigravid < primiparous direction.

Shape variations of pelvis in different classes of dogs using geometric morphometry.

The ossa coxae are the bones that connect the hindlimbs to the axial skeleton. The right and left os coxae join at the median plane to form the pelvis. In this study, variations in pelvis shape and the asymmetric structure of the pelvis were investigated across different classes of dogs. To achieve this, computed tomography images of the pelvis were obtained from 35 dogs, and 3D modelling of the pelvis was created. Subsequently, 45 landmarks were identified on these models. As a result of the Principal Component Analysis, the shape variation was observed in the pelvic canal and crista iliaca. Directional asymmetry between Principal Component 1 and Principal Component 2 accounted for 33.84% of the total variation, while fluctuating asymmetry contributed 23.66%. Canonical variate analysis revealed that canonical variate (CV) 1 explained 56.56% of the total variation between groups, with CV 2 explained 28.98%. Male dogs exhibited greater pelvic variation than females. Procrustes ANOVA indicated that the greatest proportion of shape variation corresponds to the effect of differences among individuals. While directional asymmetry was statistically significant, fluctuating asymmetry was not. Male dogs displayed more pronounced pelvic shape asymmetry, typically towards the right. Gundogs had a narrower pelvic canal and a wide crista iliaca, whereas terriers had a wider pelvic canal and smaller crista iliaca in shape. Geometric morphometry enables statistical analysis and the derivation of average shapes from samples, making it a vital tool in veterinary anatomy. This study provides insights into pelvic geometric morphometry across different classes of dogs.

Specific pelvic shape in patients with developmental dysplasia of the hip on 3D morphometric homologous model analysis.

To clarify the morphological factors of the pelvis in patients with developmental dysplasia of the hip (DDH), three-dimensional (3D) pelvic morphology was analyzed using a template-fitting technique. Three-dimensional pelvic data of 50 patients with DDH (DDH group) and 3D pelvic data of 50 patients without obvious pelvic deformity (Normal group) were used. All patients were female. A template model was created by averaging the normal pelvises into a symmetrical and isotropic mesh. Next, 100 homologous models were generated by fitting the pelvic data of each group of patients to the template model. Principal component analysis was performed on the coordinates of each vertex (15,235 vertices) of the pelvic homologous model. In addition, a receiver-operating characteristic (ROC) curve was calculated from the sensitivity of DDH positivity for each principal component, and principal components for which the area under the curve was significantly large were extracted (p<0.05). Finally, which components of the pelvic morphology frequently seen in DDH patients are related to these extracted principal components was evaluated. The first, third, and sixth principal components showed significantly larger areas under the ROC curves. The morphology indicated by the first principal component was associated with a decrease in coxal inclination in both the coronal and horizontal planes. The third principal component was related to the sacral inclination in the sagittal plane. The sixth principal component was associated with narrowing of the superior part of the pelvis. The most important factor in the difference between normal and DDH pelvises was the change in the coxal angle in both the coronal and horizontal planes. That is, in the anterior and superior views, the normal pelvis is a triangle, whereas in DDH, it was more like a quadrilateral.

Analyzing Pelvic Asymmetry by Sex and Ancestry: Insights From an Osteological Collection.

Pelvic asymmetry has been noted in pelvic imaging, and might influence the development of various spinal pathologies, most notably scoliosis. There is a limited understanding of the relationship between pelvic asymmetry and sex and ancestry, and limited use of 3D modeling. The purpose of this study was to identify pelvic asymmetry and morphology differences between sex and ancestry utilizing 3D modeling on young adults in an osteological collection. Thirty-three osteological pelvic specimens aged 18-25 years (average age 21.4 ± 2.0 years) were scanned to create virtual 3D models for analysis. Pelvic asymmetry and morphology were measured and compared across sex (male and female) and ancestry (European American and African American). Multivariate regression analysis was performed to examine the relationship between the variables measured. Multivariate regression analysis demonstrated statistically significant relationships between innominate-pelvic ring ratio and both sex (p < 0.001) and ancestry (p= 0.003) with larger ratios in male and African American specimens respectively. There was also a statistically significant relationship of greater sacral 1 coronal tilt in European American specimens (p= 0.042). There were no statistically significant differences with sex or ancestry in terms of innominate or sacral asymmetry. Although there are differences in overall pelvic shape between sex and ancestry, there is no relationship between these two variables versus pelvic asymmetry in the axial or sagittal planes in young adult osteological specimens.

Twins found in a Late Dynastic/Coptic Egyptian mummy

AbstractDuring research conducted in 2019 regarding pelvic shape in population groups and its effects on successful delivery, one of the individuals studied was a Late Dynastic/Coptic Egyptian female mummy approximately 14–17 years old (USNM catalogue number 258601). She had an associated fetus that was wrapped and placed between her legs during mummification (USNM 258602). In 1908, the mother and child were excavated and autopsied for analysis. Field notes from 1908 said she had died from obstetric complications. For our 2019 study, the mummy was CT scanned to acquire the measurements of her pelvis and determine if cephalopelvic disproportion played a role in her death. While examining the CT images, elements of what was believed to be the fetus were identified in the mother. However, there were repetitions of elements, and a second fetus was discovered in the chest cavity of the mummy. The mother was carrying twins. For this study, re‐scanning by CT and plain film radiography of the torso were performed on the mother as well as plain film radiography on the external fetus. Additionally, records and photographs from the 1908 expedition were reviewed to gather additional information on the mummy. Results note this mummy was pregnant with twins and in the middle of the birthing process at the time of her death.

Testing the reliability of the rearticulation of osteological primate pelves in comparative morphological studies.

The evolution of human pelvic form is primarily studied using disarticulated osteological material of living and fossil primates that need rearticulation to approximate anatomical position. To test whether this technique introduces errors that impact biological signals, virtual rearticulations of the pelvis in anatomical position from computed tomography scans were compared with rearticulated models from the same individuals for one female and one male of Homo sapiens, Pan troglodytes, Macaca mulatta, Lepilemur mustelinus, Galago senegalensis, and Nycticebus pygmaeus. "Cadaveric" pelvic bones were first analyzed in anatomical position, then the three bones were segmented individually, intentionally scattered, and "rearticulated" to test for rearticulation error. Three-dimensional landmarks and linear measurements were used to characterize the overall pelvis shape. Cadaveric and rearticulated pelves were not identical, but inter-specific and intra-specific shape differences were higher than the landmarking error in the cadaveric individuals and the landmarking/rearticulation error in the rearticulated pelves, demonstrating that the biological signal is stronger than the noise introduced by landmarking and rearticulation. The rearticulation process, however, underestimates the medio-lateral pelvic measurements in species with a substantial pubic gap (e.g., G. senegalensis, N. pygmaeus) possibly because the greater contribution of soft tissue to the pelvic girdle introduces higher uncertainty during rearticulation. Nevertheless, this discrepancy affects only the caudal-most part of the pelvis. This study demonstrates that the rearticulation of pelvic bones does not substantially affect the biological signal in comparative 3D morphological studies but suggests that anatomically connected pelves of species with wide pubic gaps should be preferentially included in these studies.

Artificial intelligence-based forensic sex determination of East Asian cadavers from skull morphology

Identification of unknown cadavers is an important task for forensic scientists. Forensic scientists attempt to identify skeletal remains based on factors including age, sex, and dental treatment remains. Forensic scientists commonly consider skull or pelvic shape to evaluate the sex; however, these evaluations require sufficient experience and knowledge and lack objectivity and reproducibility. To ensure objectivity and reproducibility for sex evaluation, we applied a gated attention-based multiple-instance learning model to three-dimensional (3D) skull images reconstructed from postmortem head computed tomography scans. We preprocessed the images, trained with 864 training data, validated the model with 124 validation data, and evaluated the performance of our model in terms of accuracy with 246 test data. Furthermore, three forensic scientists evaluated the 3D skull images, and their performances were compared with those of the model. Our model showed an accuracy of 0.93, which was higher than that of the forensic scientists. Our model primarily focused on the entire skull owing to visualization but focused less on the areas often investigated by forensic scientists. In summary, our model may serve as a supportive tool to identify cadaver sex based on skull shape. Further studies are required to improve the model’s performance.

A hierarchical clustering approach for examining the relationship between pelvis-proximal femur geometry and bone stress injury in runners

Bone stress injury (BSI) risk in runners is multifactorial and not well understood. Unsupervised machine learning approaches can potentially elucidate risk factors for BSI by identifying groups of similar runners within a population which differ in BSI incidence. Here, a hierarchical clustering approach is used to identify groups of collegiate cross country runners based on 2-dimensional frontal plane pelvis and proximal femur geometry, which was extracted from dual-energy X-ray absorptiometry scans and dimensionally reduced by principal component analysis. Seven distinct groups were identified using the cluster tree, with the initial split being highly related to female-male differences. Visual inspection revealed clear differences between groups in pelvis and proximal femur geometry, and groups were found to differ in lower body BSI incidence during the subsequent academic year (Rand index = 0.53; adjusted Rand index = 0.07). Linear models showed between-cluster differences in visually identified geometric measures. Geometric measures were aggregated into a pelvis shape factor based on trends with BSI incidence, and the resulting shape factor was significantly different between clusters (p < 0.001). Lower shape factor values, corresponding with lower pelvis height and ischial span, and greater iliac span and trochanteric span, appeared to be related to increased BSI incidence. This trend was dominated by the effect observed across clusters of male runners, indicating that geometric effects may be more relevant to BSI risk in males, or that other factors masked the relationship in females. More broadly, this work outlines a methodological approach for distilling complex geometric differences into simple metrics that relate to injury risk.

Pelvic shape change in adult Japanese macaques and implications for childbirth at old age

Pelvic morphology exhibits a particular sexual dimorphism in humans, which reflects obstetrical constraints due to the tight fit between neonates and mothers. Huseynov et al. [Proc. Natl. Acad. Sci. U.S.A. 113, 5227-5232 (2016)] showed that in humans, pelvic sexual dimorphism is greatest around the age of highest fertility, and it becomes less marked in association with menopause in females. They proposed that this reflects changes of obstetrical versus locomotor functional demands in females. It remains unknown whether such developmental adjustment of the pelvic morphology is unique to humans. Macaques exhibit human-like cephalopelvic proportions, but they lack menopause and usually maintain fertility throughout adulthood. Here, we track pelvic development in Japanese macaques from neonate to advanced ages using computed tomography-based data. We show that female pelvic morphology changes throughout adult life, reaching the obstetrically most favorable shape at advanced ages rather than around primiparity. We hypothesize that pelvic morphology in Japanese macaques is developmentally adjusted to childbirth at advanced ages, where obstetrical risks are potentially higher than at younger ages. Our data contribute to the growing evidence that the female primate pelvis changes its morphology during the whole lifespan, possibly adjusting for changing functional demands during adulthood.

Association between posterior tibial slope and anatomic spinopelvic parameters: a retrospective cross-sectional study

PurposeOnly a few publications considered the influence of the spinopelvic parameters on below-hip anatomy. There is a lack of evidence about the relationship between the anatomic spinopelvic parameters and the posterior tibial slope (PTS). Therefore, the aim of this study was to analyze the association between fixed anatomic spinopelvic parameters and PTS.MethodsAdult patients presenting with lumbar, thoracic, or cervical complaints together with knee pain at a single hospital between 2017 to 2022 with available standing full-spine lateral radiograph and lateral knee radiograph were retrospectively reviewed. The measured parameters included the pelvic incidence (PI), the sacral kyphosis (SK), the pelvisacral angle, the sacral anatomic orientation (SAO), the sacral table angle, the sacropelvic angle and the PTS. Pearson’s correlations and linear regression analyses were conducted.ResultsA total of 80 patients (44 women), median age 63 years were analyzed. A strong positive correlation was identified between PI and PTS (r = 0.70, p < 0.001). A strong negative correlation was observed between PI and SAO (r = − 0.74, p < 0.001). A strong positive correlation was observed between PI and SK (r = 0.81, p < 0.001). A univariable linear regression analysis showed that PTS can be deduced from PI according to the following formula: PTS = 0.174 × PI − 1.138.ConclusionThis study is the first to support a positive correlation between the PI and the PTS. We demonstrate that knee anatomy is individually correlated to pelvic shape and therefore influences spinal posture.

Changes in plasticity of the pelvic girdle from infancy to late adulthood in Homo sapiens

Previous research on the effects of body mass on the pelvic girdle focused mostly on adult females and males. Because the ontogenetic plasticity level in the pelvis remains largely unknown, this study investigated how the association between body mass index (BMI) and pelvic shape changes during development. It also assessed how the large variation in pelvic shape could be explained by the number of live births in females. Data included CT scans of 308 humans from infancy to late adulthood with known age, sex, body mass, body stature, and the number of live births (for adult females). 3D reconstruction and geometric morphometrics was used to analyze pelvic shape. Multivariate regression showed a significant association between BMI and pelvic shape in young females and old males. The association between the number of live births and pelvic shape in females was not significant. Less plasticity in pelvic shape in adult females than during puberty, perhaps reflects adaptation to support the abdominopelvic organs and the fetus during pregnancy. Non-significant susceptibility to BMI in young males may reflect bone maturation accelerated by excessive body mass. Hormonal secretion and biomechanical loading associated with pregnancy may not have a long-term effect on the pelvic morphology of females.

Development of a Statistical Shape Model and Assessment of Anatomical Shape Variations in the Hemipelvis.

Knowledge about anatomical shape variations in the pelvis is mandatory for selection, fitting, positioning, and fixation in pelvic surgery. The current knowledge on pelvic shape variation mostly relies on point-to-point measurements on 2D X-ray images and computed tomography (CT) slices. Three-dimensional region-specific assessments of pelvic morphology are scarce. Our aim was to develop a statistical shape model of the hemipelvis to assess anatomical shape variations in the hemipelvis. CT scans of 200 patients (100 male and 100 female) were used to obtain segmentations. An iterative closest point algorithm was performed to register these 3D segmentations, so a principal component analysis (PCA) could be performed, and a statistical shape model (SSM) of the hemipelvis was developed. The first 15 principal components (PCs) described 90% of the total shape variation, and the reconstruction ability of this SSM resulted in a root mean square error of 1.58 (95% CI: 1.53-1.63) mm. In summary, an SSM of the hemipelvis was developed, which describes the shape variations in a Caucasian population and is able to reconstruct an aberrant hemipelvis. Principal component analyses demonstrated that, in a general population, anatomical shape variations were mostly related to differences in the size of the pelvis (e.g., PC1 describes 68% of the total shape variation, which is attributed to size). Differences between the male and female pelvis were most pronounced in the iliac wing and pubic rami regions. These regions are often subject to injuries. Future clinical applications of our newly developed SSM may be relevant for SSM-based semi-automatic virtual reconstruction of a fractured hemipelvis as part of preoperative planning. Lastly, for companies, using our SSM might be interesting in order to assess which sizes of pelvic implants should be produced to provide proper-fitting implants for most of the population.

Pelvis shape analysis with geometric morphometry in crossbreed cats.

In this study, the geometric morphometry of the pelvis of 32 (16 male, 16 female) crossbreed cats was investigated. Pelvis images of cats were obtained by computerized tomography method. Then, these images were modelled and geometric morphometry was applied. Shape variations of the pelvis of all individuals were obtained by principal component analysis. The first principal component (PC1) value explained 18.44% of the total variation. Second principal component (PC2) and third principal component (PC3) values explained 16.84% and 13.60% of the total variation, respectively. The difference in the shape of the pelvis of female and male cats was more pronounced in PC2 and PC3, which differed in the linea terminalis. The centroid size difference in terms of sex in the Procrustes ANOVA result is statistically insignificant (p > 0.05). However, the shape difference was statistically significant (p < 0.001). As a result of discriminant analysis, the pelvis of female and male cats was completely separated from each other. The crista iliaca of males was more lateral than females. Linea terminalis was wider in shape in females. The edge of the acetabulum was higher in shape in males. Regression analysis was performed to see whether the age and weight of the cats had an effect on the centroid size of the cats. Age and weight were not found to be effective on centroid size. The shape variations of the anatomical formations obtained by geometric morphometry method can be revealed, and it can be examined whether there is a shape difference between the groups.

SYSTEMATIC REVIEW ON MATERNAL POSITION AND MOBILITY DURING FIRST STAGE OF LABOR

This systematic review is the product of 10 top published journals. The search engines adopted in this study were PubMed, Medline, Cochrane Library, Google Scholar, and Research gate. The inclusion criteria were:1. Papers published between 2004-2020, 2. Top tier journal articles (High quality), 3. Term Mobility and rst stage of labor, duration of labor, Maternal and neonatal outcome. The present highlight is that the active phase of labor enhances the effect of gravity that helps the fetus to descend comfortably as there is adequate space to move downwards as the diameter of the pelvis expands to its maximum. The pressure on the nerve in the spine during labor is reduced and thus reducing and relieving pain. If the membranes are intact, the woman is allowed to walk about. This attitude prevents vena cava compression and encourages descent of the head. Ambulation can reduce the duration of labor, need for analgesia and improve maternal comfort. Mobilization improves frequency, strength and length of contractions, decreases the use of oxytocin to augment labor and improves oxygen supply to the fetus. It improves alignment of pelvic bones and the shape and capacity of pelvis, and optimizes the good t between fetus and pelvis. This paper shows the research gaps from different studies in the review of the literature. In this present study of systematic review, 10 recent multiple interventions based on RCTs and Non RCTs studies between 2004 to 2020 were systematically reviewed using the keywords search method. The ndings are discussed and research gaps are listed accordingly Systematic review on Mobility/Ambulation during the First Stage of Labor:

The shape of the kidney pelvis in the fetus with hydronephrosis grade III as a predictor of surgical treatment in postnatal period

BACKGROUND: Fetal hydronephrosis is one of the most common malformations of the urinary system. The main goal of prenatal diagnostics is to identify a risk group with a dilatation of the renal collecting system due to mechanical obstruction of the pelvic-ureteral segment.&#x0D; AIM: The aim of the study is to definition of a prenatal risk group with a high probability of early surgical intervention in the postnatal period based on an assessment of the predictor properties of the pelvis shape in hydronephrosis grade III.&#x0D; MATERIALS AND METHODS: A prospective analysis of the results of prenatal ultrasound examination of 77 fetuses (82 renal units) with grade III hydronephrosis (SFU classification) was carried out. The anteroposterior diameter of the pelvis was measured in millimeters at the level of the kidney gate. With the ellipsoid shape of the pelvis, the compression ratio of the ellipse was calculated as the ratio of the small semi-axis of the ellipse to its large semi-axis. All parameters were recorded in the third trimester of pregnancy. The study included cases of hydronephrosis with parenchymal thickness not differing by more than two sigma deviations from the standard value. The first ultrasound examination in the postnatal period was performed during the first month of life and then at 3, 6 and 12 months.&#x0D; RESULTS: Prenatally, 57 kidneys had an elliptical pelvis and 25 funnel-shaped. The anteroposterior diameter of ellipsoid (16.5 [13; 20]) and funnel-shaped pelvis (15.0 [13; 17.8]) did not differ statistically significantly (p = 0.39). 36 (43.9%) patients were operated on, 29 of them were operated at the age of 13 months, due to the increase in APD from 17.56.0 to 27.98.2 (p = 0.001) and the transition of hydronephrosis to the IV degree by 1 month of life. The remaining 7 children had gradual progression of hydronephrosis and were operated at the age of 12 months and older. In 56.1%, resolution, regression or stabilization of hydronephrosis were noted during dynamic observation lasting 1 year. With a single-variant analysis, it was found that the configuration of the pelvis and the compression ratio of the ellipse statistically significantly correctly predicted the progression of hydronephrosis and the probability of surgery at 69.5% and 80.5%, respectively. At the same time, the compression ratio had a higher sensitivity and specificity.&#x0D; CONCLUSIONS: Fetal hydronephrosis with a funnel-shaped configuration of the pelvis, has a functional nature and regresses after birth during the first year of life. The antenatal ellipsoid configuration of the pelvis, approaching the circumference, is a statistically significant predictor of surgical intervention due to the progression of hydronephrosis due to external causes of obstruction.

An integrative approach to examining the influences of size, phylogeny, and locomotion on os coxae shape variation in primates

AbstractObjectivesAspects of three‐dimensional (3D) pelvis shape are associated with body size and adaptations to locomotor behaviors in primates, while the effect of phylogeny is less well understood. This study examines 3D os coxae shape in primates using an integrated, phylomorphospace approach to investigate the relationships among shape, phylogeny, locomotor function, and size.Materials and Methods3D landmarks (N = 20) were collected on a large sample of primate pelves (736 individuals, 60 species) and standard geometric morphometric methods were used to examine shape variation. Phylogenetic and non‐phylogenetic generalized least squares models were constructed with Procrustes coordinates as dependent variables and locomotor behavior and size as independent variables; analyses were conducted on all primates and on a nonhuman primate subsample.ResultsThe degree of phylogenetic signal in these models was statistically significant, but less than would be expected under a Brownian motion model of evolution. Among all primates, both size and locomotion have significant effects on os coxae shape while accounting for the effects of phylogeny. However, these group differences are relatively small and as a result, locomotion is not significantly related to os coxae shape among the nonhuman primate sample when accounting for phylogeny.DiscussionAlthough closely related primate taxa share locomotor behavior, there are size and locomotor differences in os coxae shape that cannot be solely accounted for by phylogeny alone and must be considered alongside previously identified mechano‐functional morphological differences. Phylogenetic comparative methods make it difficult to identify adaptation when locomotion and phylogeny are closely linked.

Spinal stability analysis of lumbar interbody fusion according to pelvic type and cage angle based on simplified spinal model with various pelvic indices.

Recently, the objectives of lumbar interbody fusion (LIF) have been extended to include the correction of broader/relative indications in addition to spinal fixation. Accordingly, LIF must be optimized for sagittal alignment while simultaneously achieving decompression. Therefore, a representative model classified into three pelvic types, i.e., neutral pelvis (NP), anterior pelvis (AP), and retroverted pelvis (RP), was selected according to the pelvic index, and LIF was performed on each representative model to analyze Lumbar lordosis (LL) and the corresponding equivalent stress. The finite element (FE) model was based on a sagittal 2D X-ray image. The calculation efficiency and convergence were improved by simplifying the modeling of the vertebral body in general and its posterior portion in particular. Based on the position of the pelvis, according to the pelvic shape, images of patients were classified into three types: AP, RP, and NP. Subsequently, representative images were selected for each type. The fixation device used in the fusion model was a pedicle screw and a spinal rod of a general type. PEEK was used as the cage material, and the cage shape was varied by using three different cage angles: 0°, 4°, and 8°. Spinal mobility: The pelvic type with the highest range of motion (ROM) for the spine was the NP type; the AP type had the highest LL. Under a combination load, the NP type exhibited the highest lumbar flexibility (LF), which was 2.46° lower on average compared to the case where a pure moment was applied. Equivalent stress on the spinal fixation device: The equivalent stress acting on the vertebrae was lowest when cage 0 was used for the NP and AP type. For the RP type, the lowest equivalent stress on the vertebrae was observed when cage 4 was used. Finally, for the L5 upper endplate, the stress did not vary significantly for a given type of cage. In conclusion, there was no significant difference in ROM according to cage angle, and the highest ROM, LL and LF were shown in the pelvic shape of NP type. However, when comparing the results with other pelvic types, it was not possible to confirm that LF is completely dependent on LL and ROM.