Age-related trends of lesser pelvic architecture in females and males: a computed tomography pelvimetry study

Population affinity estimation using pelvic measurements based on computed tomographic data acquired from Japanese and Western Australian populations

The present study analyzes morphological differences in the pelvis of Japanese and Western Australian individuals and investigates the feasibility of population affinity classification based on computed tomography (CT) data. The Japanese and Western Australian samples comprise CT scans of 207 (103 females; 104 males) and 158 (78 females; 80 males) adult individuals, respectively. Following volumetric reconstruction, a total of 19 pelvic landmarks were obtained on each sample, and 11 measurements, including two angles, were calculated. Machine learning methods (random forest modeling [RFM] and support vector machine [SVM]) were used to classify population affinity. Classification accuracy of the two-way models was approximately 80% for RFM: the two-way sex-specific and sex-mixed models for SVM achieved > 90% and > 85%, respectively. The sex-specific models had higher accurate classification rates than the sex-mixed models, except for the Japanese male sample. The classification accuracy of the four-way sex and population affinity model had an overall classification accuracy of 76.71% for RFM and 87.67% for SVM. All the correct classification rates were higher in the Japanese relative to the Western Australian sample. Our data suggest that pelvic morphology is sufficiently distinct between Japanese and Western Australian individuals to facilitate the accurate classification of population affinity based on measurements acquired in CT images. To the best of our knowledge, this is the first study investigating the feasibility of population affinity estimation based on CT images of the pelvis, which appears as a viable supplement to traditional approaches based on cranio-facial morphology.

Anthropometric study using three-dimensional pelvic CT scan in sex determination among adult Indonesian population

This study aims to determine pelvic anthropometry characteristics and logistic regression formula for adult sex identification obtained from adult three-dimensional pelvic computed tomography images. This study was an observational analytical study with retrospective regression and cross-sectional approach. The population was all patients at Radiology Installation of Dr. Soetomo General Academic Hospital as referral hospital in East Indonesian region, from September to December 2019 who underwent 3D pelvic CT examination. Then, age distribution and pelvic measurements data were obtained. In this case, statistical analysis was conducted for all the data obtained. A number of 204 samples were included in this study. All radiologic components were also significantly different between sexes (p < 0.05) except for transverse diameter of sacral segment (p = 0.180). Moreover, the conjugate pelvic inlet diameter (CPID), the left innominate height (LIH), and sub pubic angle (SPA) showed significant values for regression formula to determine an adult's sex using 3D pelvic CT. The calculation result > 0 is a prediction for female while < 0 is a prediction for male. From logistic regression model calculation, a high validity value (91.05%) was found with 100% sensitivity to identify male sex and 81.1% specificity to identify female sex. There were differences on radiometric variable characteristics in pelvic anthropometric study among adult Indonesians at Dr. Soetomo General Academic Hospital, Surabaya. The estimated values of pelvic measurements using 3D CT images could develop a pelvic model with a regression formula with high accuracy value using CPID, LIH, and SPA values.

Age targeted human body models indicate increased thoracic injury risk with aging

OBJECTIVE

The objective of this study is to generate age targeted versions of the male and female Global Human Body Models Consortium (GHBMC) occupant human body models (HBMs), to validate each in frontal impacts, and to assess rib fracture probability of each.

METHODS

Six age targeted models were developed based on the GHBMC average male and small female occupant models (M50-O v6.0 and F05-O v6.0, respectively). All age targeted models were modified to represent population means for height, weight, shape, and relevant material properties. The thin plate spline method was used to morph models, and material properties were modified using available literature. Validation focused on chest response. Models were evaluated in a rigid body frontal chest impact at 6.7 m/s. Furthermore, the male and female age targeted models were evaluated against published data from 40 km/hr and 30 km/hr frontal sled tests respectively.

RESULTS

Chest deflections and landmark kinematics reasonably matched the respective corridors in the M50-O and F05-O aged models. Regional probability of rib fracture was assessed using probabilistic methods based on cortex strain. Increasing rib fracture with age was observed in both impacts for both sexes. For the rigid chest impact, the M50-O 70YO resulted in 10 ribs exceeding 50% probability of fracture whereas the younger ages reported 4 to 6 ribs exceeding the same probability. In the same simulation, the F05-O 70YO resulted in 8 regions exceeding 50% probability of rib fracture as opposed to 3 and 0 such regions at the youngest ages. Sled simulation demonstrated similar trends. The 70YO age adjusted models best aligned with the reported extent of fractures from the referenced PMHS studies, which tend to be composed of subjects of advanced age.

CONCLUSIONS

Age targeted HBMs demonstrated increased fracture probability with age when subjected to equivalent impacts. Gross model kinematics approximate PMHS data but showed little difference between targeted age models. The findings indicate that while gross kinematics are unaffected by age-targeting models, such models can capture trends of increased thoracic injury risk observed in experimental and field studies, and further suggest their potential use to target interventions for vulnerable driving populations, such as older adults.

The evolution of pelvic canal shape and rotational birth in humans

BACKGROUND

The human foetus typically needs to rotate when passing through the tight birth canal because of the complex shape of the pelvis. In most women, the upper part, or inlet, of the birth canal has a round or mediolaterally oval shape, which is considered ideal for parturition, but it is unknown why the lower part of the birth canal has a pronounced anteroposteriorly oval shape.

RESULTS

Here, we show that the shape of the lower birth canal affects the ability of the pelvic floor to resist the pressure exerted by the abdominal organs and the foetus. Based on a series of finite element analyses, we found that the highest deformation, stress, and strain occur in pelvic floors with a circular or mediolaterally oval shape, whereas an anteroposterior elongation increases pelvic floor stability.

CONCLUSIONS

This suggests that the anteroposterior oval outlet shape is an evolutionary adaptation for pelvic floor support. For the pelvic inlet, by contrast, it has long been assumed that the mediolateral dimension is constrained by the efficiency of upright locomotion. But we argue that the mediolateral elongation has evolved because of the limits on the anteroposterior diameter imposed by upright posture. We show that an anteroposteriorly deeper inlet would require greater pelvic tilt and lumbar lordosis, which compromises spine health and the stability of upright posture. These different requirements of the pelvic inlet and outlet likely have led to the complex shape of the pelvic canal and to the evolution of rotational birth characteristic of humans.

Inter- and intrarater reliability of unidigital and bidigital vaginal palpation to evaluation of maximal voluntary contraction of pelvic floor muscles considering risk factors and dysfunctions

AIMS

To evaluate inter- and intrarater reliability of unidigital and bidigital vaginal palpation of pelvic floor muscle (PFM) maximal voluntary contraction (MVC) according to PFM risk factors and dysfunctions.

METHODS

A total of 187 women were recruited and evaluated by two examiners. Both performed the evaluation of MVC with unidigital and bidigital palpation, graded by Modified Oxford Scale. After 7-10 days, one examiner repeated the assessment. To analyze reliability by Cohen's linear Kappa (κw), participants were allocated into different groups according to: body mass index (BMI), menopause, parity, type of delivery and PFM dysfunctions, as pelvic organ prolapse (POP), constipation, urgency, urgency urinary incontinence, pelvic pain, and stress urinary incontinence.

RESULTS

Inter-rater reliability of unidigital palpation was considered fair (κw = 0.21-0.40) to moderate (κw = 0.41-0.60) according to BMI, postmenopausal status, parity, type of delivery, and PFM dysfunctions. Inter-rater reliability of bidigital palpation varied from none (κw = 0.00-0.20) to moderate for all risk factors and PFM dysfunctions. Intra-rater reliability of unidigital palpation was considered fair only for women with POP (κw = 0.37) and moderate to substantial (κw = 0.61-0.80) to all other variables. Intra-rater reliability of bidigital palpation ranged from moderate to almost perfect (κw = 0.81-1.00).

CONCLUSIONS

When performing vaginal palpation, physiotherapists must consider the way that is performing the evaluation, as some PFM risk factors and dysfunctions could influence the inter- and intrarater reliability of unidigital and bidigital palpation.

Sex estimation using subpubic angle from reconstructed three-dimensional computed tomography pelvic model in a contemporary Malaysian population

Research in forensic anthropology is recent in Malaysia due to limited access to documented skeletal collections. However, advanced imaging techniques provide virtual bone samples for use in morphometric studies to establish population-specific standards by virtual anthropology. This study examined sexual dimorphism in the subpubic angle using a three-dimensional computed tomography model of the pelvis, in a contemporary Malaysian population. The sample comprised multidetector computed tomography (MDCT) scans of 50 male and 50 female adults. Segmentation of the MDCT scans was performed using 3D Slicer, and four landmarks were acquired using Stratovan Checkpoint for the subpubic angle measurement. The technical error of measurement (TEM), relative TEM, and coefficient of reliability (R) exhibited high reliability in measurements. Results showed that the subpubic angle in males was 68.6°±7.6° and in females 87.4°±6.5°. The subpubic angle in females was significantly larger than in males (P<0.001). Inverse correlation was found between the subpubic angle and age, in both males (r=−0.449, P<0.01) and females (r=−0.385, P<0.01). The overall accuracy of sex estimation using the subpubic angle was 94% (P<0.001). The subpubic angle, with a demarcating point of 78.6°, showed a sensitivity and specificity of 94% in the classification of female individuals. In conclusion, sex estimation using the subpu bic angle is highly accurate, with a high degree of expected sensitivity and specificity in the Malaysian population.

"Comparative intra- and inter-rater reliability of maximal voluntary contraction with unidigital and bidigital vaginal palpation and construct validity with Peritron manometer"

AIMS

Evaluate the intra- and inter-rater reliability of maximal voluntary contraction (MVC) of pelvic floor muscle (PFM) assessment by unidigital and bidigital vaginal palpation. As a secondary aim, evaluate the construct validity of vaginal palpation and a manometer.

METHODS

A total of 120 women were recruited and allocated into three groups according to age (group 1 [G1]: 18-35; G2: 36-59; G3: ≥60 years). Examiner A conducted an interview and examiners B and C performed evaluations of PFM function using both unidigital and bidigital vaginal palpation. Seven to 10 days later, examiner B repeated both types of vaginal palpation and measured the MVC pressure with a Peritron. Reliability was analyzed using Cohen's linear weighted Kappa (κ_w ). The construct validity was calculated using the Spearman's correlation (r_s ).

RESULTS

Intra-rater reliability of unidigital and bidigital palpation was κ_w  = 0.75 and κ_w  = 0.58 in G1, κ_w  = 0.59 and κ_w  = 0.73 in G2, and κ_w  = 0.79 and κ_w  = 0.86 in G3, respectively. Inter-rater reliability of unidigital and bidigital palpation was κ_w  = 0.52 and κ_w  = 0.48 in G1, κ_w  = 0.47 and κ_w  = 0.52 in G2, and κ_w  = 0.50 and κ_w  = 0.64 in G3, respectively. Spearman's correlation coefficients were significant at r_s  = 0.79 and r_s  = 0.80 for unidigital and bidigital vaginal palpation, respectively.

CONCLUSIONS

Unidigital or bidigital vaginal palpation were indicated to evaluate G1 and G2 but bidigital palpation was more reliable in G3 when two examiners performed the evaluation. For the assessment conducted by one examiner, unidigital palpation was more reliable in G1 while bidigital palpation was more reliable in G2 and G3. Both unidigital and bidigital palpation have high measures of validity.