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Fertility and Sterility Jan 2023To demonstrate a step-by-step approach for restoration of pelvic anatomy in frozen pelvis using a systematic approach to make the steps reproducible, safe, and time...
OBJECTIVE
To demonstrate a step-by-step approach for restoration of pelvic anatomy in frozen pelvis using a systematic approach to make the steps reproducible, safe, and time efficient.
DESIGN
Video presentation.
SETTING
Academic medical center.
PATIENT(S)
A 30-year-old nulliparous woman with lifelong dysmenorrhea and 4 years of infertility who presented for the surgical management of stage IV endometriosis.
INTERVENTION(S)
An abdominopelvic survey was first in a systematic fashion to assess the extent of adhesive disease and evalaute for normal anatomy. Dissection was then started on the patient's left side to mobilize the sigmoid colon at the pelvic brim. Subsequently, the ureters were identified and bilateral ureterolysis was performed as the retroperitoneal spaces were explored. Once the ureters were safely dissected, the adnexa were mobilized bilaterally. Attention was then turned to the dissection of the medial pararectal spaces (Okabayashi's space) before the dissection of the rectovaginal space. With the restoration of anatomy, the remaining planned surgery was completed.
MAIN OUTCOMES MEASURE(S)
Restoration of pelvic anatomy, excision of endometriosis, and resolution of symptoms.
RESULT(S)
The patient had an uncomplicated procedure with complete excision of endometriosis and an estimated blood loss of 45 mL. She was discharged on the same day and had an uneventful postoperative period. At her follow-up appointment, she had resolution of symptoms and was initiated on medical hormone suppression therapy until ready for in vitro fertilization.
CONCLUSION(S)
A frozen pelvis is a condition in which the pelvic organs are distorted and tethered to each other as a result of adhesive processes. This can obscure normal anatomical landmarks and surgical planes making dissection extremely difficult, thus increasing the risk of interoperative and postoperative complications. Although an uncommon surgical condition, it is not rare to come across in clinical practices, thus creating a challenge to reproductive surgeons as it is commonly seen with endometriosis-associated infertility. It is important for surgeons to be able to recognize the relevant anatomy and have the knowledge to open proper pelvic avascular spaces in the pelvis to mitigate these risks. Following this video's step-by-step approach can help restore pelvic anatomy for planned surgical procedures.
Topics: Humans; Female; Adult; Laparoscopy; Endometriosis; Pelvis; Dysmenorrhea; Gastrointestinal Diseases; Infertility
PubMed: 36456208
DOI: 10.1016/j.fertnstert.2022.10.007 -
PloS One 2022The purpose of this study was to analyse the biomechanical characteristics of pedicle screws with different placement methods and diameters in the treatment of Tile C1...
OBJECTIVE
The purpose of this study was to analyse the biomechanical characteristics of pedicle screws with different placement methods and diameters in the treatment of Tile C1 pelvic fractures by finite element simulation technology and to compare them with the plate fixation model to verify the effectiveness of pedicle screw fixation.
METHODS
A three-dimensional digital model of a normal pelvis was obtained using computed tomography images. A finite element model of a normal pelvis containing major ligaments was built and validated (Model 1). Based on the verified normal pelvis finite element model, a Tile C1 pelvic fracture model was established (Model 2), and then a plate fixation model (Model 3) and a pedicle screw fixation model with different screw placement methods and diameters were established (Models 4-15). For all pelvic fracture fixation models, a vertical load of 500 N was applied on the upper surface of the sacrum to test the displacement and stress distribution of the pelvis in the standing state with both legs.
RESULTS
The finite element simulation results showed the maximum displacement of Model 1 and Models 3-15 to be less than 1 mm. The overall maximum displacement of Models 4-15 was slightly larger than that of Model 3 (the maximum difference was 177.91×10-3 mm), but the maximum displacement of iliac bone and internal fixation in Models 4-15 was smaller than that of Model 3. The overall maximum stress (maximum stress of the ilium) and maximum stress of internal fixation in Models 4-15 were less than those in Model 3. The maximum displacement difference and maximum stress difference at the fracture of the pubic ramus between each fixed model were less than 0.01 mm and 1 MPa, respectively. The greater the diameter and number of pedicle screws were, the smaller the maximum displacement and stress of the pelvic fracture models were.The maximum displacement and stress of the pelvic fracture models of the screws placed on the injured side of the pubic region were smaller than the screws on the healthy side.
CONCLUSION
Both the anterior and posterior pelvic rings are fixed with a pedicle screw rod system for treatment of Tile C1 pelvic fractures, which can obtain sufficient biomechanical stability and can be used as a suitable alternative to other implants.The greater the diameter and number of pedicle screws were, the greater the pelvic stability was, and the greater was the stability of the screws placed on the injured side of the pubic region than the screws on the healthy side.
Topics: Biomechanical Phenomena; Finite Element Analysis; Fracture Fixation, Internal; Fractures, Bone; Humans; Pedicle Screws; Pelvic Bones; Pelvis; Sacrum
PubMed: 36006983
DOI: 10.1371/journal.pone.0273351 -
Medical Physics Mar 2022The purpose of this work was to develop and validate a deep convolutional neural network (CNN) approach for the automated pelvis segmentation in computed tomography (CT)...
PURPOSE
The purpose of this work was to develop and validate a deep convolutional neural network (CNN) approach for the automated pelvis segmentation in computed tomography (CT) scans to enable the quantification of active pelvic bone marrow by means of Fluorothymidine F-18 (FLT) tracer uptake measurement in positron emission tomography (PET) scans. This quantification is a critical step in calculating bone marrow dose for radiopharmaceutical therapy clinical applications as well as external beam radiation doses.
METHODS
An approach for the combined localization and segmentation of the pelvis in CT volumes of varying sizes, ranging from full-body to pelvis CT scans, was developed that utilizes a novel CNN architecture in combination with a random sampling strategy. The method was validated on 34 planning CT scans and 106 full-body FLT PET-CT scans using a cross-validation strategy. Specifically, two different training and CNN application options were studied, quantitatively assessed, and statistically compared.
RESULTS
The proposed method was able to successfully locate and segment the pelvis in all test cases. On all data sets, an average Dice coefficient of 0.9396 0.0182 or better was achieved. The relative tracer uptake measurement error ranged between 0.065% and 0.204%. The proposed approach is time-efficient and shows a reduction in runtime of up to 95% compared to a standard U-Net-based approach without a localization component.
CONCLUSIONS
The proposed method enables the efficient calculation of FLT uptake in the pelvis. Thus, it represents a valuable tool to facilitate bone marrow preserving adaptive radiation therapy and radiopharmaceutical dose calculation. Furthermore, the method can be adapted to process other bone structures as well as organs.
Topics: Dideoxynucleosides; Image Processing, Computer-Assisted; Neural Networks, Computer; Pelvis; Positron Emission Tomography Computed Tomography; Radiopharmaceuticals
PubMed: 34982836
DOI: 10.1002/mp.15440 -
Physics in Medicine and Biology Oct 2022. This work aims to develop an automated segmentation method for the prostate and its surrounding organs-at-risk in pelvic computed tomography to facilitate prostate...
. This work aims to develop an automated segmentation method for the prostate and its surrounding organs-at-risk in pelvic computed tomography to facilitate prostate radiation treatment planning.. In this work, we propose a novel deep learning algorithm combining a U-shaped convolutional neural network (CNN) and vision transformer (VIT) for multi-organ (i.e. bladder, prostate, rectum, left and right femoral heads) segmentation in male pelvic CT images. The U-shaped model consists of three components: a CNN-based encoder for local feature extraction, a token-based VIT for capturing global dependencies from the CNN features, and a CNN-based decoder for predicting the segmentation outcome from the VIT's output. The novelty of our network is a token-based multi-head self-attention mechanism used in the transformer, which encourages long-range dependencies and forwards informative high-resolution feature maps from the encoder to the decoder. In addition, a knowledge distillation strategy is deployed to further enhance the learning capability of the proposed network.. We evaluated the network using: (1) a dataset collected from 94 patients with prostate cancer; (2) and a public dataset CT-ORG. A quantitative evaluation of the proposed network's performance was performed on each organ based on (1) volume similarity between the segmented contours and ground truth using Dice score, segmentation sensitivity, and precision, (2) surface similarity evaluated by Hausdorff distance (HD), mean surface distance (MSD) and residual mean square distance (RMS), (3) and percentage volume difference (PVD). The performance was then compared against other state-of-art methods. Average volume similarity measures obtained by the network overall organs were Dice score = 0.91, sensitivity = 0.90, precision = 0.92, average surface similarities were HD = 3.78 mm, MSD = 1.24 mm, RMS = 2.03 mm; average percentage volume difference was PVD = 9.9% on the first dataset. The network also obtained Dice score = 0.93, sensitivity = 0.93, precision = 0.93, average surface similarities were HD = 5.82 mm, MSD = 1.16 mm, RMS = 1.24 mm; average percentage volume difference was PVD = 6.6% on the CT-ORG dataset.. In summary, we propose a token-based transformer network with knowledge distillation for multi-organ segmentation using CT images. This method provides accurate and reliable segmentation results for each organ using CT imaging, facilitating the prostate radiation clinical workflow.
Topics: Humans; Image Processing, Computer-Assisted; Male; Neural Networks, Computer; Organs at Risk; Pelvis; Tomography, X-Ray Computed
PubMed: 36170872
DOI: 10.1088/1361-6560/ac95f7 -
Biological Reviews of the Cambridge... Oct 2021The term 'obstetrical dilemma' was coined by Washburn in 1960 to describe the trade-off between selection for a larger birth canal, permitting successful passage of a...
The term 'obstetrical dilemma' was coined by Washburn in 1960 to describe the trade-off between selection for a larger birth canal, permitting successful passage of a big-brained human neonate, and the smaller pelvic dimensions required for bipedal locomotion. His suggested solution to these antagonistic pressures was to give birth prematurely, explaining the unusual degree of neurological and physical immaturity, or secondary altriciality, observed in human infants. This proposed trade-off has traditionally been offered as the predominant evolutionary explanation for why human childbirth is so challenging, and inherently risky, compared to that of other primates. This perceived difficulty is likely due to the tight fit of fetal to maternal pelvic dimensions along with the convoluted shape of the birth canal and a comparatively low degree of ligamentous flexibility. Although the ideas combined under the obstetrical dilemma hypothesis originated almost a century ago, they have received renewed attention and empirical scrutiny in the last decade, with some researchers advocating complete rejection of the hypothesis and its assumptions. However, the hypothesis is complex because it presently captures several, mutually non-exclusive ideas: (i) there is an evolutionary trade-off resulting from opposing selection pressures on the pelvis; (ii) selection favouring a narrow pelvis specifically derives from bipedalism; (iii) human neonates are secondarily altricial because they are born relatively immature to ensure that they fit through the maternal bony pelvis; (iv) as a corollary to the asymmetric selection pressure for a spacious birth canal in females, humans evolved pronounced sexual dimorphism of pelvic shape. Recently, the hypothesis has been challenged on both empirical and theoretical grounds. Here, we appraise the original ideas captured under the 'obstetrical dilemma' and their subsequent evolution. We also evaluate complementary and alternative explanations for a tight fetopelvic fit and obstructed labour, including ecological factors related to nutrition and thermoregulation, constraints imposed by the stability of the pelvic floor or by maternal and fetal metabolism, the energetics of bipedalism, and variability in pelvic shape. This reveals that human childbirth is affected by a complex combination of evolutionary, ecological, and biocultural factors, which variably constrain maternal pelvic form and fetal growth. Our review demonstrates that it is unwarranted to reject the obstetrical dilemma hypothesis entirely because several of its fundamental assumptions have not been successfully discounted despite claims to the contrary. As such, the obstetrical dilemma remains a tenable hypothesis that can be used productively to guide evolutionary research.
Topics: Animals; Biological Evolution; Female; Parturition; Pelvic Bones; Pelvis; Pregnancy; Primates
PubMed: 34013651
DOI: 10.1111/brv.12744 -
IEEE Transactions on Medical Imaging Apr 2020We propose a new method for generating synthetic CT images from modified Dixon (mDixon) MR data. The synthetic CT is used for attenuation correction (AC) when...
mDixon-Based Synthetic CT Generation for PET Attenuation Correction on Abdomen and Pelvis Jointly Using Transfer Fuzzy Clustering and Active Learning-Based Classification.
We propose a new method for generating synthetic CT images from modified Dixon (mDixon) MR data. The synthetic CT is used for attenuation correction (AC) when reconstructing PET data on abdomen and pelvis. While MR does not intrinsically contain any information about photon attenuation, AC is needed in PET/MR systems in order to be quantitatively accurate and to meet qualification standards required for use in many multi-center trials. Existing MR-based synthetic CT generation methods either use advanced MR sequences that have long acquisition time and limited clinical availability or use matching of the MR images from a newly scanned subject to images in a library of MR-CT pairs which has difficulty in accounting for the diversity of human anatomy especially in patients that have pathologies. To address these deficiencies, we present a five-phase interlinked method that uses mDixon MR acquisition and advanced machine learning methods for synthetic CT generation. Both transfer fuzzy clustering and active learning-based classification (TFC-ALC) are used. The significance of our efforts is fourfold: 1) TFC-ALC is capable of better synthetic CT generation than methods currently in use on the challenging abdomen using only common Dixon-based scanning. 2) TFC partitions MR voxels initially into the four groups regarding fat, bone, air, and soft tissue via transfer learning; ALC can learn insightful classifiers, using as few but informative labeled examples as possible to precisely distinguish bone, air, and soft tissue. Combining them, the TFC-ALC method successfully overcomes the inherent imperfection and potential uncertainty regarding the co-registration between CT and MR images. 3) Compared with existing methods, TFC-ALC features not only preferable synthetic CT generation but also improved parameter robustness, which facilitates its clinical practicability. Applying the proposed approach on mDixon-MR data from ten subjects, the average score of the mean absolute prediction deviation (MAPD) was 89.78±8.76 which is significantly better than the 133.17±9.67 obtained using the all-water (AW) method (p=4.11E-9) and the 104.97±10.03 obtained using the four-cluster-partitioning (FCP, i.e., external-air, internal-air, fat, and soft tissue) method (p=0.002). 4) Experiments in the PET SUV errors of these approaches show that TFC-ALC achieves the highest SUV accuracy and can generally reduce the SUV errors to 5% or less. These experimental results distinctively demonstrate the effectiveness of our proposed TFCALC method for the synthetic CT generation on abdomen and pelvis using only the commonly-available Dixon pulse sequence.
Topics: Abdomen; Cluster Analysis; Fuzzy Logic; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Pelvis; Positron-Emission Tomography; Support Vector Machine; Tomography, X-Ray Computed
PubMed: 31425065
DOI: 10.1109/TMI.2019.2935916 -
Ideggyogyaszati Szemle Sep 2019To understand if children with and without cerebral palsy share the same lumbar postural control threshold on the sagittal plane for the transition between each walking...
BACKGROUND AND PURPOSE
To understand if children with and without cerebral palsy share the same lumbar postural control threshold on the sagittal plane for the transition between each walking locomotor stage.
METHODS
Observational analysis of sagittal trunk-pelvis kinematics of 97 children with cerebral palsy and 73 with typical development, according to their locomotor stage.
RESULTS
Among children with typical development, all average and minimum measurements of the sagittal lumbar curve during the gait events were correlated with age and the locomotor stages of development. Among children with cerebral palsy, there were significant correlations between all average and minimum values of the sagittal lumbar curve and locomotor stages of development but not age.
CONCLUSION
We conclude that, for the same locomotor level, there are no common postural patterns between children with typical development and those with spastic bilateral cerebral palsy for the position between trunk and pelvis in the sagittal plane. Maximal lordosis reduction between trunk and pelvis may change with age or even training, but does not make a positive effect on the locomotor level, while basal and maintenance capacities could explain locomotor function. Trials that failed to assess quality of movement may now have a better understanding of how different interventions improve posture towards the next functional level.
Topics: Biomechanical Phenomena; Cerebral Palsy; Child; Child, Preschool; Female; Gait; Humans; Male; Motor Skills; Pelvis; Posture; Range of Motion, Articular; Spine; Torso
PubMed: 31625701
DOI: 10.18071/isz.72.0343 -
Journal of Digital Imaging Dec 2022The rotation and tilt of the pelvis during anteroposterior pelvic radiography can lead to misdiagnosis of developmental dysplasia of the hip (DDH) in children. At... (Randomized Controlled Trial)
Randomized Controlled Trial
The rotation and tilt of the pelvis during anteroposterior pelvic radiography can lead to misdiagnosis of developmental dysplasia of the hip (DDH) in children. At present, no method exists for accurately and conveniently measuring the precise rotation and tilt angles of pelvic on radiographs. The objective of this study was to develop several rotation and tilt measurement models using transfer learning and digital reconstructed radiographs (DRRs), and to compare their performances on pelvic radiographs. Based on the inclusion criteria, 30 of 92 children who underwent 3D hip CT scans at Xijing Hospital from 2015 to 2020 were included in the study. Using DRR techniques, radiographs were generated by rotating and tilting the pelvis in CT datasets at - 12 to 12° (projected every 3°) and were randomized to a 2:1:1 ratio of training dataset, validation dataset, and test dataset. Five pre-trained networks, including VGG16, Xception, VGG19, ResNet50 and InceptionV3 were used to develop pelvic rotation measurement models and tilt measurement models, and these models were trained with training dataset. The callback function was used during the training to slow down the learning rate when learning was stalled. Then, the validation set was used to optimize each model and compare their performances. At last, we tested the final performances of optimal rotation measurement model and optimal tilt measurement model on test dataset. The mean absolute error (MAE) was employed to assess the performance of the models. A total of 2430 pelvic DRRs were collected based on 30 CT datasets. Among 5 pre-trained transfer learning models, VGG16-Tilt achieved the best tilt prediction performance at the same BS and different LR. VGG16-Tilt model achieved its best performance on validation set at LR = 0.001 and BS = 4, and the final MAE on the test set was 0.5250°. In terms of rotation prediction, VGG16-Rotation also achieved the best performance, and it achieved its best performance on validation set at LR = 0.002 and BS = 8. The final MAE of VGG16-Rotation on the test set was 1.0731°. Pretrained transfer learning models worked well in predicting tilt and rotation angles of the pelvis on radiographs in children. Among them, VGG16-Tilt and VGG16-Rotation had the best effect in dealing with such problems despite their simple structures. These models deployed in devices can give orthopedic surgeons a powerful aid in DDH diagnosis.
Topics: Child; Humans; Rotation; Radiography; Pelvis; Diagnostic Errors; Machine Learning
PubMed: 35711070
DOI: 10.1007/s10278-022-00672-1 -
Proceedings of the National Academy of... Sep 2020A large brain combined with an upright posture in humans has resulted in a high cephalopelvic proportion and frequently obstructed labor. Fischer and Mitteroecker [B....
A large brain combined with an upright posture in humans has resulted in a high cephalopelvic proportion and frequently obstructed labor. Fischer and Mitteroecker [B. Fischer, P. Mitteroecker, 112, 5655-5660 (2015)] proposed that the morphological covariations between the skull and pelvis could have evolved to ameliorate obstructed labor in humans. The availability of quantitative data of such covariation, especially of the fetal skull and maternal pelvis, however, is still scarce. Here, we present direct evidence of morphological covariations between the skull and pelvis using actual mother-fetus dyads during the perinatal period of , a species that exhibits cephalopelvic proportions comparable to modern humans. We analyzed the covariation of the three-dimensional morphology of the fetal skull and maternal pelvis using computed tomography-based models. The covariation was mostly observed at the pelvic locations related to the birth canal, and the forms of the birth canal and fetal skull covary in such a way that reduces obstetric difficulties. Therefore, cephalopelvic covariation could have evolved not only in humans, but also in other primate taxa in parallel, or it could have evolved already in the early catarrhines.
Topics: Animals; Anthropology, Physical; Biological Evolution; Cephalopelvic Disproportion; Delivery, Obstetric; Female; Fetus; Hominidae; Humans; Macaca mulatta; Parturition; Pelvis; Pregnancy; Skull
PubMed: 32817513
DOI: 10.1073/pnas.2002112117 -
Journal of Digital Imaging Feb 2020Patient-specific 3D modeling is the first step towards image-guided surgery, the actual revolution in surgical care. Pediatric and adolescent patients with rare tumors... (Review)
Review
Patient-specific 3D modeling is the first step towards image-guided surgery, the actual revolution in surgical care. Pediatric and adolescent patients with rare tumors and malformations should highly benefit from these latest technological innovations, allowing personalized tailored surgery. This study focused on the pelvic region, located at the crossroads of the urinary, digestive, and genital channels with important vascular and nervous structures. The aim of this study was to evaluate the performances of different software tools to obtain patient-specific 3D models, through segmentation of magnetic resonance images (MRI), the reference for pediatric pelvis examination. Twelve software tools freely available on the Internet and two commercial software tools were evaluated using T2-w MRI and diffusion-weighted MRI images. The software tools were rated according to eight criteria, evaluated by three different users: automatization degree, segmentation time, usability, 3D visualization, presence of image registration tools, tractography tools, supported OS, and potential extension (i.e., plugins). A ranking of software tools for 3D modeling of MRI medical images, according to the set of predefined criteria, was given. This ranking allowed us to elaborate guidelines for the choice of software tools for pelvic surgical planning in pediatric patients. The best-ranked software tools were Myrian Studio, ITK-SNAP, and 3D Slicer, the latter being especially appropriate if nerve fibers should be included in the 3D patient model. To conclude, this study proposed a comprehensive review of software tools for 3D modeling of the pelvis according to a set of eight criteria and delivered specific conclusions for pediatric and adolescent patients that can be directly applied to clinical practice.
Topics: Humans; Imaging, Three-Dimensional; Magnetic Resonance Imaging; Pelvis; Software; Surgery, Computer-Assisted
PubMed: 31236743
DOI: 10.1007/s10278-019-00239-7