BACKGROUND AND OBJECTIVE: The prevalence of pelvic floor muscle injuries induced by childbirth is higher than 23 % in the general women population. Such injuries can lead to prolapses and other pathologies in future female life. Leveraging computational biomechanics, the study implements an advanced female pelvic floor model for computing the maximum pelvic muscle strain, which serves as an injury risk indicator. The design of experiment method, abbreviated as DoE, is used to compute the maximum strain for boundary values of bony pelvis dimensions, namely the anterior-posterior diameter (abbreviated as APD) and the transverse diameter (abbreviated as TD). This is done in combination with small, medium and large percentiles of fetal head circumference (abbreviated as HC). METHODS: We utilized a previously developed finite element model of a female pelvic floor, as a reference, and enhanced it with new features, including a more detailed tissue geometry and advanced constitutive material models. The APD and TD dimensions were sourced from the set of MRI of 64 nulliparous women. This data was used to estimate the boundary dimensions of the female bony pelvis, combining both small and large values of APD and TD. Together with the 10th and the 95th percentiles for HC, a three-dimensional domain was constructed to assess the maximum pelvic muscle strain. In boundary cases, the maximum pelvic muscle strain was computed across 8 full-factorial design models (each situated at one corner of the domain, thereby combining the minimum and the maximum values of APD, TD and HC). This was done to define a response surface that predicts the maximum pelvic muscle strain within the domain. The accuracy of this response surface prediction was validated using 15 additional intermediate design models. These models were placed at the center of the domain (1 point), the centres of the domain boundary surfaces (6 points), and midway along each domain boundary edge (8 points). RESULTS: The maximum strain results for 8 combinations of APD, TD, and HC were employed to construct a linear response surface as a function of APD, TD, and HC. Tests at an additional 19 domain points served to evaluate the efficiency of the response surface prediction. The response surface demonstrated strong predictability, with an absolute average error of 1.52 %, an absolute median error of 1.52 %, and an absolute maximum error of 11.11 %. HC emerged as the most influencing dimension, accounting for 16 % of influence. CONCLUSIONS: The reference finite element pelvic floor model was scaled to 8 full-factorial female-specific pelvic floor models, which represent the combination of boundary values for APD, TD, and HC. The maximum pelvic floor muscle strain from these 8 models was used to design a response surface. When implementing the DoE approach to construct the response, there was consistent predictability for the maximum perineal muscle strain, as validated by the additional 19 intermediate design models. As a result, the response surface methodology can serve as an initial predictor for potential childbirth-induced pelvic floor muscle injury.
- MeSH
- kosterní svaly diagnostické zobrazování MeSH
- lidé MeSH
- magnetická rezonanční tomografie MeSH
- pánevní dno diagnostické zobrazování fyziologie MeSH
- porod * fyziologie MeSH
- těhotenství MeSH
- vedení porodu * MeSH
- Check Tag
- lidé MeSH
- těhotenství MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
OBJECTIVES: Postpartum retained products of conception are a relatively rare diagnosis occurring in approximately 1% of cases after spontaneous deliveries and abortions. The most common clinical signs are bleeding and abdominal pain. The diagnosis is based on clinical signs and ultrasound examination. MATERIAL AND METHODS: Retrospective analysis of 200 surgical procedures for the diagnosis of residua postpartum obtained in 64 months. We correlated the method and accuracy of diagnosis with definitive histological findings. RESULTS: During 64 months, we performed 23 412 deliveries. The frequency of procedures for diagnosis of retained products of conception (RPOC) was 0.85%. Most (73.5%) of the D&C were performed within six weeks of delivery. Histologically, the correct diagnosis was confirmed in 62% (chorion + amniotic envelope). There was interestingly lower concordance of histologically confirmed RPOC in post-CS patients (only 42%). In women after spontaneous delivery of the placenta, the diagnosis of RPOC was confirmed by histological correlate in 63%, and the highest concordance occurred in women after manual removal of the placenta in 75%. CONCLUSIONS: Concordance with histological findings of chorion or amnion was seen in 62% of cases; this means that the incidence rate in our study was around 0.53%. The lowest concordance is after CS deliveries, 42%. D&C for RPOC should be performed after adequate clinical evaluation and in the knowledge of 38% false positivity. There is certainly more space for a conservative approach under appropriate clinical conditions, especially in patients after CS.
- MeSH
- komplikace těhotenství * MeSH
- lidé MeSH
- poporodní období MeSH
- retrospektivní studie MeSH
- samovolný potrat * MeSH
- těhotenství MeSH
- zadržená placenta * diagnostické zobrazování chirurgie epidemiologie MeSH
- Check Tag
- lidé MeSH
- těhotenství MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
INTRODUCTION AND HYPOTHESIS: We aimed to summarize the knowledge on the pathogenesis of pelvic organ prolapse (POP) generated in animal models. METHODS: We searched MEDLINE, Embase, Cochrane and the Web of Science to establish what animal models are used in the study of suggested risk factors for the development of POP, including pregnancy, labor, delivery, parity, aging and menopause. Lack of methodologic uniformity precluded meta-analysis; hence, results are presented as a narrative review. RESULTS: A total of 7426 studies were identified, of which 51 were included in the analysis. Pregnancy has a measurable and consistent effect across species. In rats, simulated vaginal delivery induces structural changes in the pelvic floor, without complete recovery of the vaginal muscular layer and its microvasculature, though it does not induce POP. In sheep, first vaginal delivery has a measurable effect on vaginal compliance; measured effects of additional deliveries are inconsistent. Squirrel monkeys can develop POP. Denervation of their levator ani muscle facilitates this process in animals that delivered vaginally. The models used do not develop spontaneous menopause, so it is induced by ovariectomy. Effects of menopause depend on the age at ovariectomy and the interval to measurement. In several species menopause is associated with an increase in collagen content in the longer term. In rodents there were no measurable effects of age apart of elastin changes. We found no usable data for other species. CONCLUSION: In several species there are measurable effects of pregnancy, delivery and iatrogenic menopause. Squirrel monkeys can develop spontaneous prolapse.
- MeSH
- krysa rodu rattus MeSH
- modely u zvířat MeSH
- ovce MeSH
- pánevní dno MeSH
- parita MeSH
- prolaps pánevních orgánů * MeSH
- těhotenství MeSH
- vedení porodu MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- těhotenství MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- systematický přehled MeSH
