A biomechanical study of the birth position: a natural struggle between mother and fetus.

Birth trauma affects millions of women and infants worldwide. Levator ani muscle avulsions can be responsible for long-term morbidity, associated with 13-36% of women who deliver vaginally. Pelvic floor injuries are enhanced by fetal malposition, namely persistent occipito-posterior (OP) position, estimated to affect 1.8-12.9% of pregnancies. Neonates delivered in persistent OP position are associated with an increased risk for adverse outcomes. The main goal of this work was to evaluate the impact of distinct fetal positions on both mother and fetus. Therefore, a finite element model of the fetal head and maternal structures was used to perform childbirth simulations with the fetus in the occipito-anterior (OA) and OP position of the vertex presentation, considering a flexible-sacrum maternal position. Results demonstrated that the pelvic floor muscles' stretch was similar in both cases. The maximum principal stresses were higher for the OP position, and the coccyx rotation reached maximums of 2.17[Formula: see text] and 0.98[Formula: see text] for the OP and OA positions, respectively. Concerning the fetal head, results showed noteworthy differences in the variation of diameters between the two positions. The molding index is higher for the OA position, with a maximum of 1.87. The main conclusions indicate that an OP position can be more harmful to the pelvic floor and pelvic bones from a biomechanical point of view. On the other side, an OP position can be favorable to the fetus since fewer deformations were verified. This study demonstrates the importance of biomechanical analyses to further understand the mechanics of labor.

Deep learning and capsule endoscopy: automatic identification and differentiation of small bowel lesions with distinct haemorrhagic potential using a convolutional neural network.

OBJECTIVE: Capsule endoscopy (CE) is pivotal for evaluation of small bowel disease. Obscure gastrointestinal bleeding most often originates from the small bowel. CE frequently identifies a wide range of lesions with different bleeding potentials in these patients. However, reading CE examinations is a time-consuming task. Convolutional neural networks (CNNs) are highly efficient artificial intelligence tools for image analysis. This study aims to develop a CNN-based model for identification and differentiation of multiple small bowel lesions with distinct haemorrhagic potential using CE images. DESIGN: We developed, trained, and validated a denary CNN based on CE images. Each frame was labelled according to the type of lesion (lymphangiectasia, xanthomas, ulcers, erosions, vascular lesions, protruding lesions, and blood). The haemorrhagic potential was assessed by Saurin's classification. The entire dataset was divided into training and validation sets. The performance of the CNN was measured by the area under the receiving operating characteristic curve, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). RESULTS: A total of 53 555 CE images were included. The model had an overall accuracy of 99%, a sensitivity of 88%, a specificity of 99%, a PPV of 87%, and an NPV of 99% for detection of multiple small bowel abnormalities and respective classification of bleeding potential. CONCLUSION: We developed and tested a CNN-based model for automatic detection of multiple types of small bowel lesions and classification of the respective bleeding potential. This system may improve the diagnostic yield of CE for these lesions and overall CE efficiency.

Effect of the birthing position on its evolution from a biomechanical point of view.

BACKGROUND AND OBJECTIVE: During vaginal delivery, several positions can be adopted by the mother to be more comfortable and to help the labor process. The positions chosen are very influenced by factors such as monitoring and intervention during the second stage of labor. However, there is limited evidence to support the most ideal birthing position. This work aims at contributing to a better knowledge associated with the widening of the pubic symphysis and the biomechanics of flexible and non-flexible sacrum positions that can be adopted during the second stage of labor, as well as their resulting pathophysiological consequences. METHODS: A validated computational model composed by the pelvic floor muscles attached to the bones, and a fetus head was used to simulate vaginal deliveries. This model was modified to mimic two birthing positions: one that allows the free movement of the coccyx as in flexible sacrum positions and other in which this movement is more restricted as in non-flexible sacrum positions. The widening of the pubic symphysis was also considered to facilitate the passage of the fetus head. RESULTS: The results obtained showed that, in non-flexible sacrum positions, where the coccyx movement is restricted, occur a rotation of 3.6° of the coccyx and a widening of 6 mm of the pubic symphysis. In contrast, in flexible sacrum positions, where the coccyx is free to move, occur a rotation of 15.7° of the coccyx and a widening of the pubic symphysis of 3 mm, appearing to be more beneficial for the mother's pelvis, but slightly higher stresses were detected in the pelvic floor muscles. CONCLUSIONS: Globally, the results obtained allow to conclude that different birthing positions lead to changes in the female pelvic space, so certain positions can be adopted by the mother during the second stage of labor to reduce the risk of obstructed labor and the development of several dysfunctions. More specifically, flexible sacrum positions, such as kneeling, standing, squatting and sitting positions, are more beneficial for the bone structure of her pelvis as they allow a higher coccyx movement and lower widening of the pubic symphysis.

A numerical study on fetal head molding during labor.

During vaginal delivery, the fetal head molds into an elongated shape to adapt to the birth canal, a process known as fetal head molding. However, excessive molding can occur due to prolonged labor or strong contractions, leading to several disorders on the fetal head. This work aims to perform a numerical study on the biomechanics of fetal head molding by measuring specific diameters and the corresponding molding index. A finite element model of the pelvic floor muscles and the fetal body was used. The fetal head is composed of the skin and soft tissues, the skull with sutures and fontanelles, and the brain. The sutures and fontanelles were modeled with membrane elements and characterized by a visco-hyperelastic constitutive model adapted to a plane stress state. Simulations were performed to replicate the second stage of labor in the vertex presentation and occipito-anterior position. With the introduction of viscoelasticity to assess a time-dependent response, a prolonged second stage of labor resulted in higher molding. The pressure exerted by the birth canal and surrounding structures, along with the presence of the pelvic floor muscles, led to a percentage of molding of 9.1%. Regarding the pelvic floor muscles, a 19.4% reduction on the reaction forces and a decrease of 2.58% in muscle stretching was reported, which indicates that sufficient molding may lead to fewer injuries. The present study demonstrates the importance of focusing on the fetus injuries with non-invasive methods that can allow to anticipate complications during labor.

Evaluation of the pelvic floor muscles training in older women with urinary incontinence: a systematic review.

BACKGROUND: Urinary incontinence (UI) is defined as any involuntary urine loss that predominantly affects older women. There is evidence that pelvic floor muscles training (PFMT) program is effective on the treatment of pelvic floor (PF) dysfunctions and is considered to be first-line treatment. The evaluation of pelvic floor muscles (PFM) function and strength is central to validate the effectiveness of the training protocol in UI decrease. The Oxford Grading Scale and manometry are fundamental to evaluate the PFM function and strength. OBJECTIVE: The aim of the study was to systematize the scientific evidence about the effects of PFMT in older women, assessing the PF function and strength through Oxford Grading Scale and manometry. METHODS: The research of randomized controlled clinical trials was performed through B-on, EBSCO, PEDro, Pubmed, and SciELO data carried out from 2003 to 2016. RESULTS: A total of 35 studies were identified, 26 of these were selected and fully analyzed. From the analyzed studies (n = 26), 20 were excluded for not meeting the criteria for inclusion, and only 6 studies were classified as high methodological quality, scoring an overall 4 points according the PEDro scale. CONCLUSION: The PFMT seems to be effective in treating UI in older women; the Oxford Grading Scale and manometry are considered the most reliable in the random and controlled clinical trials results. However, future investigations with high methodological quality with older women are necessary to support these results.

Numerical study of Hough technique in surgery of otosclerosis, using the finite element method.

PURPOSE: Otosclerosis is a metabolic bone disease of the otic capsule that can cause the stapes fixation, resulting in conductive hearing loss or, in a profound sensorineural deafness threshold. Surgery is one of the possible treatments for the otosclerosis. To repair small focus of otosclerosis in the anterior crus of the stapes, in 1960, Hough suggested the implementation of a technique in which part of the anterior crus is fractured and the stapes turned. As a result, the posterior crus of the stapes is the only connection with the inner ear. In this work, the outcome of Hough's surgical technique was simulated. METHODS: Based on computerized images, a finite element model of middle ear ossicles and tympanic membrane was created, as well as a model where the stapes has changed. The discretization of the tridimensional solid model was made using the ABAQUS software. The mechanical properties used were taken from the literature and adequate boundary conditions were applied. RESULTS: The results obtained with the Hough technique simulation were compared with a representative model of the normal ear, taking into account the displacements obtained on the central part of the stapes footplate and the maximum principal stress in the stapes crus. CONCLUSIONS: The results obtained are closer to the normal ear model, therefore Hough technique stands out as a good option to correct small focus of otosclerosis.

Comparison of otoacoustic emissions in patients with tinnitus having normal hearing versus mild hearing loss.

INTRODUCTION: Tinnitus is an auditory sensation whose source comes from external stimulus to the body. All studies that can help people with this disorder are very imperative. OBJECTIVE: This study investigates the cochlear function in patients with tinnitus, using Distortion Products Otoacoustic Emissions (DPOAE). MATERIAL AND METHODS: Ears where the subjects referred to feel the tinnitus were considered for the study group while other ears without this sensation of tinnitus acted as a control group. Fifty subjects suffering from unilateral or bilateral tinnitus with normal hearing sensitivity or mild hearing loss were recruited. RESULTS AND CONCLUSIONS: Where comparing the control and study group, the highest percentage of cases of DPOAE detected was in the control group, although these differences were not statistically significant. When the analyzed frequency is the same as the tinnitus frequency, the prevalence of detected DPOAE is in tinnitus ears (50.0 %). In ears where tinnitus was not perceived (73.5 %) a p value of 0.024 (< 0.05) was found, which means that the undetected DPOAE could be influenced by tinnitus. Based on the results, tinnitus might not be caused by changes in the outer hair cells but seems to be affected by that.

Application of a finite element model in the diagnosis process of middle ear pathologies.

The ear is a complex organ that can be affected by various pathologies that are still fairly misunderstood. This work tests the possibilities of studying the ear and its pathologies using a virtual environment and thus bypassing expensive and time-consuming clinical trial. A previous validated finite element model of the middle ear was employed to study two pathological states of the middle ear. It was shown that the model obtained results very close to the clinical evaluation thus proving of being a proper tool for further investigations of middle ear pathologies.