A safe, low-cost, easy-to-use 3D camera platform to assess risk of obstructed labor due to cephalopelvic disproportion.

Cephalopelvic disproportion (CPD)-related obstructed labor is accountable for 3-8% of the maternal deaths worldwide. The consequence of CPD-related obstructive labor in the absence of a Caesarian section (C/S) is often maternal or perinatal mortality or morbidity to the mother and/or the infant. Accurate and timely referral of at-risk mothers to health facilities where C/S is a delivery option could reduce maternal mortality in the developing world. The goal of this work was to develop and test the feasibility of a safe, low-cost, easy-to-use, portable tool, using a Microsoft Kinect 3D camera, to identify women at risk for obstructed labor due to CPD. Magnetic resonance imaging (MRI) scans, 3D camera imaging, anthropometry and clinical pelvimetry were collected and analyzed from women 18-40 years of age, at gestational age ≥36+0 weeks with previous C/S due to CPD (n = 43), previous uncomplicated vaginal deliveries (n = 96), and no previous obstetric history (n = 148) from Addis Ababa, Ethiopia. Novel and published CPD risk scores based on anthropometry, clinical pelvimetry, MRI, and Kinect measurements were compared. Significant differences were observed in most anthropometry, clinical pelvimetry, MRI and Kinect measurements between women delivering via CPD-related C/S versus those delivering vaginally. The area under the receiver-operator curve from novel CPD risk scores base on MRI-, Kinect-, and anthropometric-features outperformed novel CPD risk scores based on clinical pelvimetry and previously published indices for CPD risk calculated from these data; e.g., pelvic inlet area, height, and fetal-pelvic index. This work demonstrates the feasibility of a 3D camera-based platform for assessing CPD risk as a novel, safe, scalable approach to better predict risk of CPD in Ethiopia and warrants the need for further blinded, prospective studies to refine and validate the proposed CPD risk scores, which are required before this method can be applied clinically.

The pelvic radius technique in the assessment of spinopelvic sagittal alignment of degenerative spondylolisthesis and lumbar spinal stenosis.

BACKGROUND: Degenerative spondylolisthesis (DS) and lumbar spinal stenosis (LSS) are the most common degenerative spinal diseases. The evaluating of spinopelvic sagittal alignment of the two diseases using pelvic radius (PR) technique have not been reported. The purpose of this study was to use PR measurement technique to compare the differences in spinopelvic sagittal alignment between DS and LSS. METHODS: A total of 145 patients with DS or LSS were retrospectively reviewed. Seventy patients with DS (DS group) and 75 age-matched patients with LSS (LSS group) were enrolled. Spinopelvic parameters including pelvic angle (PA), regional lumbopelvic lordosis (PR-L1, PR-L2, PR-L3, PR-L4 and PR-L5), total lumbopelvic lordosis (PR-T12), pelvic morphology (PR-S1), sagittal vertical axis from the C7 plumb line (SVA), lumbar lordosis (LL), thoracic kyphosis (TK), L4 slope and L5 slope were assessed in the two groups. Several parameters of DS and LSS group were compared with the normal population (NP). RESULTS: The PR-L4, PR-L5 and PR-S1 in the DS group were significantly smaller than those in the LSS group. There was no difference in PR-T12 between the DS group and NP (p > 0.05), while PR-T12 of the LSS group were significantly lower (p < 0.01). Degree of correlations among spinopelvic parameters differed between the two groups. PR-T12 of the DS group was more strongly correlated with PA (r = -0.829, p < 0.001) than with LL (r = 0.664, p < 0.001), TK (r = 0.582, p < 0.001). PR-T12 of the LSS group was more strongly correlated with LL (r = 0.854, p < 0.001), TK (r = 0.616, p < 0.001) than with PA (r = -0.582, p < 0.001). CONCLUSIONS: PR-L4 and PR-L5 may be the predisposing factors for DS development. Spinopelvic morphology differed in patients with DS and LSS compared to NP. The compensatory mechanisms to maintain spinopelvic sagittal alignment in DS and LSS patients may be different.

Can three-dimensional pelvimetry using low-dose stereoradiography replace low-dose CT pelvimetry?

PURPOSE: To evaluate the reliability of pelvimetric measurements performed using stereoradiographic imaging (SRI), and to assess maternal and fetal radiation doses compared to low-dose computer tomography (CT) pelvimetry. MATERIALS AND METHODS: Thirty-five pregnant women (mean age, 29.6±5.5 [SD] years; range: 20-41 years) were prospectively included. All women underwent simultaneous frontal and lateral low-dose SRI and low-dose CT examination of the pelvis. Pelvimetry measurements were obtained from both examinations and radiation doses obtained with the two techniques were compared. RESULTS: SRI-CT correlation (Pearson coefficient correlation [r]; mean bias [mb]) was strong for transverse inlet diameter (r=0.92; mb=-0.09cm), anteroposterior diameter of the pelvic inlet (r=0.92; mb = 0.47cm), maximal transverse diameter (r=0.9; mb=0.21cm), sacrum length (r=0.9; mb=0.09cm). Correlation was good. Correlation was good for the sacrum depth (r=0.75; mb=0.06cm) and Magnin's index (r=0.7; mb=0.5cm). Correlation was moderate for anteroposterior diameter of pelvic outlet (r=0.6; mb=0.52cm). The fetal dose was 13.1 times lower using SRI (87±26µGy) than CT (1140±220µGy, P<0.0001). The effective maternal dose was 3.1 times lower using SRI (97±21µSv) than CT (310±60µSv; P<0.0001). CONCLUSION: Pelvic inlet measurements using SRI are reliable. Compared to CT pelvimetry, SRI leads to a significant decrease in fetal and maternal radiation doses. These findings should prompt physicians to use SRI as the first-line approach for pelvimetry.

Comparison between the Valsalva maneuver and intraoperative traction measurements in pelvic organ prolapse assessment.

OBJECTIVE: To compare the assessment of pelvic organ prolapse (POP) between the Pelvic Organ Prolapse Quantification (POP-Q) system with Valsalva maneuver and intraoperative measurement with mechanical traction. METHODS: A prospective observational study included 100 women with POP attending a tertiary urogynecology clinic in the UK and undergoing vaginal prolapse surgical procedures between October 2011 and October 2014. The women were examined in the clinic using POP-Q with the Valsalva maneuver and in the operating theater under general anesthesia with mechanical traction. The two sets of measurements were compared. RESULTS: All POP-Q measurements obtained with traction demonstrated significantly higher descent as compared with those measured by Valsalva maneuver (mean differences: Aa 0.64 cm; Ap 1.32 cm; Ba 0.96 cm; Bp 1.34 cm; C 3.57 cm; D 3.40 cm; all P<0.001). The perineal body and total vaginal lengths did not differ significantly. CONCLUSION: Measurements of six POP-Q points obtained with traction showed a higher grade of POP than those assessed with Valsalva maneuver. On this basis, surgeons might decide on the extent of surgical procedure after examination under anesthesia; however, preoperative patient counselling would be essential to obtain consent for this approach. The clinical significance of the findings requires further evaluation.

Sexual dimorphism in relative sacral breadth among catarrhine primates.

As the sacrum contributes to the size and shape of the birth canal, the sexually dimorphic sacrum of humans is frequently interpreted within obstetric contexts. However, while the human sacrum has been extensively studied, comparatively little is known about sacral morphology in nonhuman primates. Thus, it remains unclear whether sacral sexual dimorphism exists in other primates, and whether potential dimorphism is primarily related to obstetrics or other factors such as body size dimorphism. In this study, sacra of Homo sapiens, Hylobates lar, Nasalis larvatus, Gorilla gorilla, Pongo pygmaeus, Pan troglodytes, and Pan paniscus were evaluated for sexual dimorphism in relative sacral breadth (i.e., the ratio of overall sacral breadth to first sacral vertebral body breadth). Homo sapiens, H. lar, N. larvatus, and G. gorilla exhibit dimorphism in this ratio. Of these, the first three species have large cephalopelvic proportions, whereas G. gorilla has small cephalopelvic proportions. P. pygmaeus, P. troglodytes, and P. paniscus, which all have small cephalopelvic proportions, were not dimorphic for relative sacral breadth. We argue that among species with large cephalopelvic proportions, wide sacral alae in females facilitate birth by increasing the pelvic inlet's transverse diameter. However, given the small cephalopelvic proportions among gorillas, an obstetric basis for dimorphism in relative sacral breadth appears unlikely. This raises the possibility that sacral dimorphism in gorillas is attributable to selection for relatively narrow sacra in males rather than relatively broad sacra in females. Accordingly, these results have implications for interpreting pelvic dimorphism among fossil primates, including hominins.

MRI assessment of the bony pelvis may help predict resectability of rectal cancer.

OBJECTIVE: The outcome after surgical treatment of rectal cancer may be influenced by the technical difficulty of the operation, which is thought to be affected by pelvic size. The aim of this study was to examine the association between bony pelvic dimensions and CRM involvement. PATIENTS AND METHODS: All patients with primary rectal cancer between December 1999 and January 2002 were studied. Staging was performed by pelvic MRI. Nine pelvic dimensions were measured from the MR images on a workstation. Pathology reports were obtained for all patients and the mesorectal specimen was examined. Technical difficulty was assessed by circumferential resection margin (CRM) involvement. RESULTS: Of 126 patients with primary rectal cancer, 88 had staging MRI and rectal excision; there were significant differences between the sexes in all 9 pelvic dimensions (P < 0.05). In females, the interspinous diameter was significantly shorter in patients with CRM involvement compared with patients with a negative CRM. In female patients predicted to have a negative CRM, the anteroposterior diameter of the inlet, the anteroposterior diameter of the midplane and the transverse diameter of the midplane (interspinous distance) were significantly shorter in patients who actually had a positive CRM compared with those in whom the CRM was negative. In male patients, there was no correlation between pelvic dimensions and CRM status. CONCLUSIONS: In certain patients with rectal cancer, CRM positivity may be predicted from pre-operative MRI pelvic measurements. This may influence the choice of adjuvant therapy.

Computed tomographic pelvimetry in German shepherd dogs.

Pelvimetry was performed on a computed tomographic scanner using dorsal and lateral scout-view images of 10 adult German shepherd dogs. The vertical and transverse diameters of the pelvis were measured and the pelvic inlet and pelvic outlet areas were also calculated. No significant correlations between the pelvic measurements and body weight, age and sex were found. Although the conjugata vera, diameter verticalis, diameter sacralis, sagittal diameter and the distance between the two medial tubera ischiadica were longer in females, no significant statistical difference was found between male and female animals for all measurements. It is proposed that the computed tomographic pelvimetry should be preferred for the sensitive measurements when the normal standards are determined for different animal species and the cost is reduced to an acceptable level.

Pelvimetry and patient acceptability compared between open 0.5-T and closed 1.5-T MR systems.

Our objective was to compare maternal pelvimetry and patient acceptability between open low-field (0.5-T) and closed 1.5-T MR systems. Thirty women referred for pelvimetry (pregnant: n=15) were scanned twice in the supine position, once in the vertical open system and once in the closed system. Each patient completed a comfort and acceptability questionnaire. Pelvimetric and questionnaire data were compared between systems. Total scan time was double in the open system (7:52+/-1:47 vs 3:12+/-1:20 min). Poor image quality in the open system prevented assessment of interspinous and intertuberous diameters in one woman and all measurements in another, both pregnant, with abdominal circumferences >120 cm. The open system was much more acceptable in terms of claustrophobia and confinement (both p<0.01). Claustrophobia interrupted one closed examination. Thirty-three percent of pregnant women in both systems reported fear of fetal harm. Sixty percent of all women preferred the open system, 7% the closed system, and 33% had no preference. Limits of agreement of 3-5% from the mean for all diameters confirmed good pelvimetric reproducibility. Women's preference for open-system MR pelvimetry is feasible with abdominal circumferences

Radiographic pelvimetry for assessment of dystocia in bitches: a clinical study in two terrier breeds.

Radiographic pelvimetry was used to assess the role of pelvic anatomy in obstructive dystocia in bitches. Based on the history of previous whelpings, 20 Boston terrier and 14 Scottish terrier bitches were divided into two equal groups: normally whelping bitches and bitches with obstructive dystocia. Additional whelpings during the period of study were closely observed and the pups were immediately weighed and measured. The bitches were clinically examined and the pelvis was radiographed in ventrodorsal and lateral projections. Measurements from the radiographs showed a significantly smaller pelvic size in the bitches with obstructive dystocia compared to the normally whelping bitches. Fetal-pelvic disproportion in the Scottish terrier was mainly due to a dorsoventrally flattened pelvic canal, whereas in the Boston terrier it arose from the combination of a dorsoventrally flattened pelvic canal and big fetuses with large heads. These results suggest that radiographic pelvimetry could be used to predict a disposition for dystocia in individual bitches, and as a basis for selection of breeding animals.

Assessment of computed tomographic pelvimetry within a selective breech presentation management protocol.

A vital component of selective protocols in term breech presentation management is exclusion of the gravida with borderline pelvic dimensions. Computed tomographic (CT) pelvimetry was employed to evaluate potential candidates for a trial of labor with a breech fetus at term. Thirty-seven of 39 women who underwent labor after this selection had a successful assisted vaginal breech delivery. Adequate pelvic dimensions by CT pelvimetry reliably predicted a safe vaginal delivery in patients managed within a standard breech protocol.

[Methods, techniques and assessment criteria in obstetric pelvimetry]. / Methoden, Techniken und Beurteilungskriterien der geburtshilflichen Pelvimetrie.

Size and shape of the bony pelvis are important factors determining the progress of labor and delivery. Clinical evaluation of the pelvis and sonographic examination of the fetal size are important tools for the planning of labor and in most cases allow to diagnose cephalopelvic disproportion. Pelvimetry by computed tomography (CT) and by magnetic resonance imaging (MRI) are exact and simple techniques with low or absent ionizing radiation. These new techniques offer distinct advantages over conventional X-ray pelvimetry. However, the value of the measurements of the pelvic dimensions in predicting labor outcome and in the diagnosis of cephalopelvic disproportion remains limited. Only if the pelvimetric data are combined with data on fetal dimensions obtained by ultrasound or by postpartum measurements, the efficacy of the examination in predicting the success of labor and identifying the presence or absence of cephalopelvic disproportion is increased. This combination therefore may confirm the diagnosis of cephalopelvic disproportion after operative delivery, which is important with respect to subsequent deliveries. Furthermore this method could play and important role in selecting patients with term breech presentation for possible vaginal delivery.

Maternal height and shoe size as predictors of pelvic disproportion: an assessment.

A total of 351 women who gave birth in the Paddington and North Kensington Health District were studied in order to establish a factual basis for recording height and shoe size as indicators of pelvic adequacy. Because only 19 women had radiological pelvimetry assessment, type of delivery and length of labour were used as proxy measures of disproportion. Of the 57 women with a shoe size less than 4 1/2, 21% were delivered by caesarean section compared with 10% of the group with shoe size between 4 1/2 and 6 and only 1% of the group with shoe size greater than or equal to 6 1/2. Similar relations with height were not generally found. The data were further examined using logistic regression models of the expected percentages of mothers having an adverse delivery. The models confirmed and extended the more simple analysis.

Assessment of the predictive value of X-ray pelvimetry and biparietal diameter in cephalopelvic disproportion.

The value of X-ray pelvimetry and ultrasonic measurement of the biparietal diameter for trial of labor prognosis was assessed in 172 healthy primiparas with suspected cephalopelvic disproportion. A decision diagram which is able to correctly predict 50% of the cesarean sections without increasing the number of unnecessary cesarean sections is proposed. In addition, the study confirms the superfluity of X-ray pelvimetry in cases of high station of the fetal head at the end of pregnancy.

Assessment of dystocia pelvis by ultrasound pelvimetry.

Following successful preceding studies, a quantitative analysis of the female pelvic cavity was made using contact compound scanning procedures. The subjects were seventy-seven, 3 day postpartum women and ultrasonic tomograms were obtained concerning the five pelvic transections in each individual. For the quantitative analysis, variables of binary digits were used. Such were based on the standard of "normopelvis" in the polar coordinate system plus the external criteria, normal progress of labor, protraction and arrest disorders. Characteristics of the dystocia pelvis included an abnormal side wall of the small pelvis as well as an increased resistance of the muscles of the pelvic floor. The efficiency of the discrimination was greatest when those variables were adopted from each transection (78.3%). Arrest disorders could be clearly distinguished from the normal cases, however, cases of protraction disorder presented more difficulty as the distribution was wide between normal and the arrest disorder. Here, the pelvic floor muscles contribute significantly. The newly developed numerical system should make feasible an early prediction of dystocia, assist in screening processes and pave the way for accurate assessments of the interaction of anatomical factors related to the mechanics and processes of labor.