Interspinous Diameter Research Articles

Variations in pelvic floor thickness in relation to bony dimensions in South African women: using computed tomography scans

Pelvic floor disorders (PFDs) are a common reason for urogynaecological consultation around the world, especially in elderly women. These disorders have been associated with disruption to the structural integrity of the pelvic floor. This study explored whether there are variations in pelvic floor muscle (PFM) thickness in relation to parity, population group and age. Additionally, the study explored whether there were any correlations between PFM thickness and the bony pelvic parameters measured. This was a quantitative retrospective analysis of computerised tomography (CT) scans. A total of 125 CT scans of women belonging to black and white South African population groups were sampled from a tertiary hospital in Pretoria, South Africa. Statistical analyses were performed using Paleontological Statistics (PAST). A thicker pelvic floor was noted in black compared to white women. Pelvic floor thickness decreased with parity and age in both population groups. The intertuberous diameter, as well as the surface areas of the urogenital triangle and the perineum, were statistically significantly larger in white than in black women. Correlations between PFM thickness and bony dimensions were statistically significant for anteroposterior (AP) pelvic outlet diameter, where a greater AP outlet was associated with thinner PFMs in black women. Bony correlations with parity showed that the interspinous diameter in black women increased significantly with parity. The variations in bony pelvic dimensions and pelvic floor muscle thicknesses noted between population groups, in addition to the co-factors of parity and aging, will contribute to a better understanding of the anatomical reasons for incontinence.

Risk factors for ischemia/necrosis of the colonic stump after proctectomy and delayed coloanal anastomosis.

Delayed coloanal anastomosis (DCAA) is a two-stage procedure. DCAA has been increasingly reused in recent years in the management of rectal cancer. Such increased use of DCAA has highlighted the complications associated with this procedure. We aimed to evaluate the risk and risk factors of ischemia/necrosis of the colonic stump between the two stages of DCAA. All patients who underwent a proctectomy with a DCAA were included in this retrospective single-centre study from November 2012 to June 2022. Two groups of patients were defined: patients with a well vascularized colonic stump (well vascularized group) and those who experienced ischemia or necrosis of the colonic stump (ischemic group). The primary endpoint was the rate of ischemia or necrosis of the colonic stump and an evaluation of the associated risk factors. During the study period, 43 patients underwent DCAA. Amongst them, 32 (75%) had a well-vascularized colonic stump (well-vascularized group) and 11 (25%) ischemia of the colonic stump (ischemic group). Relative to patients in the well-vascularized group, those in the ischemic group were more often men (81.8% vs 40.6%, p = 0.034), had a higher BMI (29.2kg/m2 vs 25.7kg/m2, p = 0.03), were more frequently diabetic (63.6% vs 21.9%, p = 0.01) and more frequently had had preoperative radiotherapy (100% vs 53.1%, p = 0.008). On the preoperative CT scan, the interspinous diameter was shorter in the ischemic group (9.4 ± 1.01cm vs 10.6 ± 1.01cm, p = 0.001), the intertuberosity diameter was shorter (9.2 ± 1.18cm vs 11.9 ± 1.18cm, p < 0.0001), and the length of the anal canal was longer (31.9 ± 3mm vs 27.4 ± 3.2mm, p < 0.0001). This study highlights clear risk factors for ischemia/necrosis of the colonic stump after proctectomy with DCAA.

Magnetic resonance imaging pelvimetric measurements as predictors for emergent cesarean delivery in obstructed labor.

This study aimed to investigate the usefulness of various magnetic resonance imaging (MRI) pelvimetric parameters for predicting emergent cesarean delivery due to obstructed labor. This was a prospective observational study. MRI pelvimetry was performed in cases of a clinically suspected maternal narrow pelvis, maternal short stature, fetal overgrowth, and abnormal placental position. MRI pelvimetry was performed at 34.7±4.2 gestational weeks using a 1.5T MRI system. The pelvic inlet angle, pelvic inclination, obstetric conjugate, sacral outlet diameter (SOD), and coccygeal pelvic outlet were measured in the sagittal section. The interspinous diameter and intertuberous diameter were measured in coronal sections. Fetal anomalies, cesarean deliveries before the onset of labor, and non-reassuring fetal status were excluded from the analysis. MRI pelvimetry was performed in 154 patients. After excluding 76 cases, including 19 cases of absolute cephalopelvic disproportion, 78 cases of trial of labor were included. Of these, 63 were vaginal deliveries and 15 were emergent cesarean deliveries due to obstructed labor. The cut-off value for body mass index (BMI) was 22.2, with an area under the curve (AUC) of 0.69, for predicting obstructed labor. The cut-off value for the SOD was 10.7cm with an AUC of 0.69. BMI alone had a sensitivity of 80%, specificity of 66%, positive predictive value (PPV) of 36%, and negative predictive value (NPV) of 93%. When BMI and SOD were combined, sensitivity was 53%, specificity was 90%, PPV was 57%, and NPV was 89%. The odds ratio for emergent cesarean delivery was 5.42 (95% confidence interval 1.06-27.6, p=0.041) if the SOD was less than the cut-off value in the binomial logistic regression analysis in cases with an BMI >22. We confirmed that MRI pelvimetry was a reliable tool for better patient selection for obstructed labor. The SOD was the best predictor of obstructed labor, with a cut-off value of 10.7cm for women with a low BMI.

Comparison of Bony Pelvic Dimensions and Demographic Risk Factors in Individuals With and Without Pelvic Organ Prolapse [ID: 1377653

INTRODUCTION: Previous studies have noted a correlation between bony pelvic measurements and the diagnosis of prolapse via musculofascial insertion points on magnetic resonance imaging. We investigated the importance of bony measurements of the lumbar spine and pelvis as risk factors in the development of prolapse via routine computed tomography (CT) imaging. METHODS: We sampled 171 UBMD obstetrics and gynecology clinic patients who were at least 40 years of age and had an abdominal/pelvic CT scan. Demographic and medical history was reviewed and collected. Participants were then divided into those with and without prolapse. CT images were uploaded to 3D Slicer 5.10. Each study was analyzed by a trained annotator blinded to prolapse status. The area of the anterior pelvis, interspinous diameter, pelvic outlet, ischial spine to pubic symphysis, sacrococcygeal junction to ischial spine, and lumbar and sacrococcygeal curvature were annotated. Demographic characteristics and measured annotations were compared using χ2 test. RESULTS: Women with prolapse were more likely to be older (P&lt;.05) and of lower weight (mean 71.6 kg, P&lt;.05) than controls. Patients with prolapse had a significantly larger area of their anterior pelvis (P&lt;.05) and a significantly longer interspinous diameter (P&lt;.05). Distance from ischial spine to pubic symphysis was significantly longer (P&lt;.05), and pelvic outlet in women with prolapse was significantly longer than in controls (P&lt;.05). CONCLUSION: In addition to known risk factors, bony measurements of the pelvis are significantly different in those with and without pelvic organ prolapse, which may be observed on routine CT imaging.

Comparison of the anterior pelvis and levator ani muscle on MRI in women with and without anterior pelvic organ prolapse.

The objective was to compare the differences in pelvic and levator ani muscle diameters in women with and without anterior pelvic organ prolapse. Three groups were included, including 50 nulliparous women (nulliparous group), 50 women with stage III-IV anterior vaginal prolapse (prolapse group), and 50 women of the same age as the prolapse group but without prolapse (nonprolapse control group). The ischial interspinous diameter (ISD), anterior pelvic area (APA), levator defect score (LDS), levator ani hiatus width (LH-W), H-line, M-line, levator ani plate length, levator ani plate angle, and cervix length (CL) were measured. There were no significant differences in ISD (10.6±0.8 vs 10.6±0.9cm), LH-W (3.0±0.4 vs 3.3±0.4cm), or CL (2.9±0.6 vs 3.0±0.5cm) between the nulliparous group and the nonprolapse control group (p>0.05). However, there were significant differences between them and the prolapsed group (11.2±0.6cm, 3.6±0.4cm, 4.2±1.5cm; p<0.05). There were no significant differences in LDS (0.70±0.61 vs 0.70±0.65) or APA (58.4±8.4 vs 60.1±7.4 cm2) between the nonprolapse control group and the prolapse group (p>0.05), but they were significantly different from those of the nulliparous group (0.08±0.34, 55.1±6.0 cm2) (p<0.05). The area under the receiver-operating characteristic curve for the ISD of nonprolapse control and prolapse groups was 0.713, and the cutoff value was 10.95cm. The levator ani hiatus width and cervix length were larger in patients with anterior vaginal prolapse than in those without prolapse. An ischial ISD greater than 10.95cm was associated with prolapse.

Predictive Value of MRI Pelvimetry in Vaginal Delivery and Its Practicability in Prolonged Labour-A Prospective Cohort Study.

Pelvic dimensions are crucial variables in the labour process. We used magnetic resonance imaging (MRI) pelvimetry to predict the probability of vaginal delivery and distinguish the cephalopelvic disproportion risk in women with prolonged active labour. This prospective cohort study enrolled term nulliparous women willing to undergo MRI pelvimetry and a trial of labour. A nomogram, with vaginal birth as the outcome, was developed and evaluated by calibration curve and decision curve analyses. The pairwise association between maternal and fetal parameters and a prolonged first stage of labour was quantified. Head circumference (HC), abdominal circumference (AC), intertuberous distance (ITD), interspinous diameter (ISD), and body mass index (BMI) were introduced to develop a nomogram with good diagnostic performance (area under the curve = 0.799, sensitivity = 83%, and specificity = 73%). The cephalopelvic index of diameter (CID) in 54 women with a prolonged first stage of labour was much smaller in those who delivered via cesarean section compared with those who delivered vaginally (18.09 ± 1.14 vs. 21.29 ± 1.06; p = 0.046). An MRI pelvimetry-based nomogram may predict the probability of vaginal delivery. Practitioners should reassess the pelvimetry parameters to decide whether the trial of labour should be continued if it is prolonged.

Do the Externally Measurable Pelvic Diameters Estimate the Relevant Birth Canal Parameters in A Reproductive-Age Woman? Pelvimetry by Reformatted Computed Tomography at Sodo Christian Hospital, Southern Ethiopia

Introduction: Assessment of the size of the female pelvis is an important obstetric practice to identify mothers at risk of cephalopelvic disproportion. Due to the problem of accessing radiological instruments to carry out pelvimetry in health centers of resource-limited countries, clinical pelvimetry remains a routine practice. The present study was aimed at assessing the prediction capability of intertuberous diameter, anterior interspinal diameter, and bi-trochanteric diameters on the pelvic inlet and mid-pelvis diameters as an alternative method to estimate different birth canal parameters. Subjects and Methods: Institution-based retrospective cross-sectional study design was conducted on randomly selected 423 abdominopelvic computed tomography images of reproductive-age women who visited Sodo Christian hospital from September 2018 to November 2020. Pelvic diameters were measured on a 3D workstation using multiplanar reconstruction and volume rendering images. Pearson’s correlation, partial correlation, and multivariate regression analysis were done for assessing the relationship between the variables by using STATA 16. Results: The present study demonstrated that the intertuberous diameter (ITD) is a significant predictor of obstetric conjugate diameter (OCD), the transverse diameter of the pelvic inlet (TDI), and interspinous diameter (ISD). A millimeter increase in ITD is associated with 0.552 mm, 0.558 mm, and 0.74 mm increase in OCD, TDI, and ISD, respectively. The TDI is the only lesser pelvis diameter significantly predicted by the anterior interspinal diameter (AISD). A millimeter increase in AISD is associated with a 0.229 mm increase in TDI. Jointly the ITD and AISD were shown to predict 81% of TDI. The bi-trochanteric diameter (BTD) was found statistically insignificant predictor of OCD, TDI, and ISD. Conclusion: As to the present study, the ITD is a potential predictor of the pelvic inlet and mid pelvic diameters. Besides, only the TDI could be estimated from AISD, whereas the BTD could not estimate any of the birth canal parameters.

Magnetic resonance imaging pelvimetry predicts the technical difficulty of rectal surgery

BackgroundThe relationships between the pelvimetry and technical difficulties in performing rectal surgery for mid-low rectal cancer remain unclear. MethodsTwo hundred and twenty-one cases of mid-low rectal cancer patients who underwent sphincter-preserved total mesorectum excision (TME) were analyzed. The data of the pelvimetry and the relative position between trocar site and tumor were measured with magnetic resonance imaging (MRI). ResultsUnivariate analysis showed that the interspinous diameter, the sacrococcygeal distance, and the angle of sacral promontory inclination were significantly associated with the technical difficulty during laparoscopic surgery, but only the interspinous diameter remained an independent risk factor in multivariate analysis. The simulated trocar angle θ was an independent risk factor affecting the operation time during laparoscopic surgery, simulated trocar angle η was significantly related to intraoperative blood loss in both laparoscopic surgery and transanal TME (taTME) surgery groups. ConclusionInterspinous diameter can predict difficulty in laparoscopic surgery and may provide useful information for preoperative planning and consideration of approach.

Comparing the pelvis of Tibetan and Chinese Han women in rural areas of China: two population-based studies using coarsened exact matching

This study aims to investigate the difference of pelvic size and shape between Tibetan and Chinese Han women. Data on pelvic dimension measures including interspinous diameter (IS), intercrestal diameter (IC), external conjugate (EC) and transverse outlet (TO) were acquired from two population-based studies amongst Tibetan women in Lhasa, and Chinese Han women in Shaanxi province in China. After coarsened exact matching, there was no statistical difference between any characteristics amongst Tibetan and Chinese Han women (p>.05). The generalised estimating equation models showed Tibetan women had significantly lower IS and IC means than Chinese Han women (IS: 24.39 cm vs. 24.77 cm, p<.001; IC: 26.35 cm vs. 26.93 cm, p<.001) but statistically higher in TO mean (9.12 cm vs. 9.03 cm, p<.001). This study showed Tibetan women have smaller pelvis compared to Chinese Han women. This should offer a useful literature on the comparison of pelvis between Tibetan and Chinese Han women although the difference is small. Impact Statement What is already known on this subject? Previous studies in China indicated different populations have different dimensions of pelvis, with the pelvis of Uighur women being bigger than Chinese Han women, and that of Zhuang and Tu women being smaller than Chinese Han women. Little research reports the specific size of Tibetan women’s pelvis. Living at high altitude, the Tibetan population have differentiated demographics and show local adaptions, such as unelevated haemoglobin, and significant catch-up growth for infants compared with Chinese Han infants. Therefore, there is a strong rationale for better understanding pelvic characteristics amongst this population. What the results of this study add? This study showed Tibetan women have smaller pelvises compared to Chinese Han women. Tibetan women have a smaller interspinous diameter and intercrestal diameter than Chinese Han women, which leads to relatively narrow hip. What the implications are of these findings for clinical practice and/or further research? This study provides useful comparative information on pelvic features between Tibetan and Chinese Han women although the findings of differences were small. In addition, during the formulation of women’s health policy, the results of this study can provide data to support the selection of appropriate indicators of obstetrics and gynaecology for different populations of pregnant women during antenatal care and delivery.

Pelvic and neonatal size correlations in light ofevolutionary hypotheses.

This study aimed to analyze the correlations between maternal size, neonatal size, and gestational variables. Our sample comprises 131 mother-infant dyads. We investigated correlations between five neonatal traits (gestational age, birthweight, head, suboccipito-brematic, and abdominal girths), three maternal traits (height, BMI, and uterus height), and three pelvic variables (conjugate, inter-spinous diameters, and sub-pubic angle) using computed tomography pelvimetry. We found that the five neonatal traits were significantly intercorrelated. BMI was not correlated with neonatal traits while maternal height was correlated with birthweight, suboccipito-brematic, and abdominal girth. In the multiple regression models, gestational age was correlated with birthweight, head, and abdominal girth. Among the neonatal and pelvimetry correlations, conjugate diameter was slightly correlated with suboccipito-bregmatic girth, but inter-spinous and sub-pubic angle were not correlated with neonatal traits. Uterus height predicted all neonatal variables, but it was not correlated with gestational age. Our results suggest that fetal growth is shaped by maternal phenotype rather than external ecological factors. The association of the inlet size with suboccipito-bregmatic girth reflects the tight fit between the neonatal brain and the maternal pelvis dimensions, an adaptation that would reduce the risk of cephalo-pelvic disproportion, while the absence of tight fit at the midplane and outlet could be due to the effect of the pelvic relaxation. Uterus distention is not the only mechanism involved in the initiation of parturition. Birth and pregnancy are complex processes and we suggest that maternal-neonatal associations are the result of a combination of multiple obstetric tradeoffs.

Pelvic cross-sectional area at the level of the levator ani and prolapse.

Intraabdominal pressure acts on the pelvic floor through an aperture surrounded by bony and muscular structures of the pelvis. A small pilot study showed the area of the anterior portion of this plane is larger in pelvic organ prolapse. We hypothesize that there is a relationship between prolapse and anterior (APA) and posterior (PPA) pelvic cross-sectional area in a larger, more diverse population. MRIs from 30 prolapse subjects and 66 controls were analyzed in this case-control study. The measurement plane was tilted to approximate the level of the levator ani attachments. Three evaluators made measurements. Patient demographic characteristics were compared using Wilcoxon rank-sum and Fisher's exact tests. A multivariable logistic regression model identified factors independently associated with prolapse. Controls were 3.7years younger and had lower parity, but groups were similar in terms of race, height, and BMI. Cases had a larger APA (p < 0.0001), interspinous diameter (ISD) (p = 0.001), anterior-posterior (AP) diameter (p = 0.01), and smaller total obturator internus muscle (OIM) area (p = 0.002). There was no difference in the size of the PPA(p = 0.12). Bivariate logistic regression showed age (p = 0.007), parity (p = 0.009), ISD (p = 0.002), AP diameter (p = 0.02), APA (p < 0.0001), and OIM size (p = 0.01) were significantly associated with prolapse; however, PPA was not (p = 0.12). After adjusting for age, parity, and major levator defect, prolapse was significantly associated with increased anterior pelvic area (p = 0.001). We confirm that a larger APA and decreasing OIM area are associated with prolapse. The PPA was not significantly associated with prolapse.

Determination of The Relationship Between External Pelvic Measurements and Body Mass Index in Young Adults

Objective: This study was conducted to evaluate the relationship between pelvic measurements and body mass index (BMI) among pre-pregnancy young adult women in our population. Method: The sample group consisted of 83 midwifery students who agreed to participate in the study. The anthropometric pelvic measurements which are intercrestal diameter (IC), interspinous diameter (IS), intertrochanteric diameter (IT), intertuberous diameter (ITb), and Baudelocque diameter (anteroposterior diameter) was obtained by a single investigator with a pelvimeter. The program Statistical Package for Social Sciences (version 21.0) was used to create a descriptive analysis, and the Pearson correlation coefficient was performed to determine significance (p0.05). Results: The participants’ mean age was 19.72±1.16. The mean values of BMI, IC, IS, IT, ITb and Baudelocque diameter of participants were 22.71±3.26, 27.88±1.74, 25.31±2.01, 32.54±2.23, 12.41±1.51, and 20.40±1.62, respectively. Significant positive correlations were found between IC and BMI (r=0.434), IS and BMI (r=0.285), IT and BMI (r=0.051), and Baudelocque diameter and BMI (r=0.502). No significant differences were found between ITb and BMI (r=0.051 and p&amp;gt;0.05). Conclusion: The data indicates that IC, IS, IT, and Baudelocque diameter all correlate with BMI.

Sacrococcygeal dimensions and curvature are associated with resection quality in rectal cancer excision.

Technical factors affect oncologic outcomes in rectal cancer surgery. The anatomy of the bony pelvis can affect technical aspects of surgery, but is seldom considered preoperatively. We performed a morphometric analysis of the bony pelvis in patients having rectal cancer resection to assess its effect on surgical specimen quality. We performed a retrospective analysis of a prospectively maintained database of patients who had resection for rectal cancer from January 2014 to December 2017. Preoperative magnetic resonance imaging (MRI) and computed tomography (CT) images were accessed and measurements of sacrococcygeal distance, sacrococcygeal recess depth/area, sacrococcygeal angulation, anteroposterior pelvic inlet/outlet, pubic height and interspinous distance were made. Outcome measures included anatomical variation, operating time and mesorectal specimen grade. In patients having extra-levator abdominoperineal excision (eLAPE) with coccygectomy, the completeness of coccygeal resection was assessed by postoperative CT scan. Data were analysed using binomial and multinomial logistic regression and linear regression. One hundred and twenty-two consecutive rectal cancer resections were performed (39 open, 42 laparoscopic, 12 laparoscopic-converted and 29 robotic). The median age was 72years (range: 29-88years). The male:female ratio was 83:39. Eighty-one patients had anterior resection, 8 had low Hartmann's resection and 32 had APE. Of those who had APE, 21 had eLAPE (all with coccygectomy). Females had a larger pelvic inlet (female: 124.9mm, male: 114.9mm), interspinous diameter(female:112.8mm, male:97.6mm), sacrococcygeal depth (female:42.6mm, 39.35mm) and sacrococcygeal area recess than males (female: 3697mm2, male: 3481.5mm2). Males had a greater pubic height (female: 51.8mm, male: 54.05mm) and greater sacrococcygeal distance (female: 116.7mm, male: 123.65mm) than females. In patients having anterior resection, tumour distance from the anal verge (p = 0.004), sacrococcygeal distance (p = 0.006) and sacrococcygeal curvature (p = 0.002) were associated with specimen quality. In patients who had eLAPE, median preoperative coccygeal length was 41mm (IQR: 35.1-45.5). The median length of coccygeal resection was 9mm (IQR: 1-17.45mm). The median length of coccyx remaining postoperatively was 33mm (IQR: 21.35-39mm). Sacrococcygeal curvature and distance as well as tumour distance from the anal margin were associated with specimen quality in anterior resection. Coccygectomy was not performed as completely as surgeons thought. Surgeons should include sacrococcygeal bony anatomy in rectal cancer surgical planning to potentially improve outcomes in both anterior resection and eLAPE approaches.

Investigation of correlation between bony pelvis dimensions and pelvic organ prolapse in different compartments

ObjectiveTo investigate the association between bony pelvis dimensions and anterior, apical, and posterior compartment pelvic organ prolapse (POP) and explore the mechanism of different types of POP from an anatomical point of view. Study designA total of 253 patients with POP were selected as the experimental group (138 patients with anterior compartment defect, 86 with apical compartment defect, and 29 with posterior compartment defect); 253 patients with uterine myoma constituted the control group. Their demographics were recorded, and anteroposterior diameters of the pelvic inlet, intertuberous diameter, and interspinous diameter were measured. One-way analysis of variance, least significant difference t-test, and Student’s t-test were used to evaluate the pelvic measurements among the four groups. ResultsThe anteroposterior diameter of the pelvic inlet in the apical compartment POP group was smaller than that in the other groups (P < 0.05). Interspinous diameters in the anterior and apical groups were larger than those in the posterior POP and control groups (P < 0.05). Intertuberous diameter in the control group was smaller than that in the anterior and apical POP groups and larger than that in the posterior POP group (P < 0.05). ConclusionWomen with apical compartment POP are more likely to have a smaller anteroposterior diameter. Larger interspinous and intertuberous diameters were associated with anterior and apical POP, and smaller intertuberous diameter was associated with posterior POP.

Neonatal Size and Birth Canal Dimensions

The limitation of the fetal growth process during pregnancy is supposed to be an adaptative response to a physical or a physiological constraint: the pelvic size or the maternal resources and metabolism. In this study 131 mother-infant dyads were recruited. We investigate correlation between maternal traits (height, BMI) pelvic variables (conjugate diameter, inter-spinous diameter, sub-pubic angle) and neonatal traits (gestational age, birthweight, head, suboccipito-brematic and abdominal girth). We found that the three neonatal variables are significantly inter-correlated. Among maternal traits, height is highly correlated with conjugate and inter-spinous diameters. Subpubic angle is correlated with inter-spinous diameter. Among neonatal and pelvimetry correlations, conjugate diameter is highly correlated with suboccipito-bregmatic girth. The pelvic size seems to be the primary constraint to the fetal growth process. This adjustement of fetus size to the birth canal dimensions limits the risk of dystocia. But the way this adjustement occurs at the end of pregnancy is unclear. We assume that the uterus expansion limitation may be an intermediate mechanism explaining the high correlation between pelvic and neonatal traits.

Evaluation of the link between pelvimetry based on computed tomography and predicting status’ delivery

Objectives: The aim of this study is an anthropometric study in non-pregnant reproductive-aged women to predicting kind of delivery. Methods: This study was based on the archived information of Hazrat-e Rasool university hospital on 157 generative age women from 16 to 60 years old. who underwent CT between March of 2015 until March of 2018. Results: The obtained results showed that the three conjugates on sagittal plane, transverse diameter, anteroposterior sagittal diameter, interspinous diameter and intertuberous diameter on the coronal plane. The obstetrical conjugate was (123.3 mm in normal vaginal delivery and 113.9 mm in Cesarean section) which it was slightly longer than delivery group. The mean interspinous and intertuberous diameters measured by CT scans were 105.0 mm and 107.4 mm. Conclusion: The results of our study showed that because of the reduction in diameter of the inlet and middle pelvis, the rate of cesarean section was higher in under 35 years ages.

Developmental origins of variability in pelvic dimensions: Evidence from nulliparous South Asian women in the United Kingdom.

ObjectivesPelvic growth may be sensitive to early‐life nutrition, with implications for maternal risk of obstructed labor. However, the “developmental origins” of adult pelvic variability require further investigation. We tested whether adult pelvic dimensions are associated with two components of height, indexing different periods of linear growth: tibia length, a proxy for early postnatal growth, and height‐residual (height regressed on tibia length), a proxy for later growth. We also tested whether adult pelvic dimensions are associated with birth weight, a marker of nutritional investment in utero.MethodsIn this cross‐sectional study, data were obtained on 68 nulliparous young women of South Asian ancestry. Pelvic dimensions (bi‐iliac and bi‐acetabular breadth, anteroposterior pelvic inlet and outlet, interspinous and intertuberous diameter) were measured using magnetic resonance imaging. Height and tibia length were measured manually. Birth weight and gestational age were obtained by recall. Multivariable regression models were fitted with a given pelvic dimension regressed on height‐residual, tibia, and birth weight, with the latter adjusted for gestational age.ResultsControlling for birth weight, height‐residual was predictive of bi‐acetabular breadth, bi‐iliac breadth, and the pelvic inlet, while tibia length significantly predicted all dimensions except interspinous diameter. Controlling for the linear growth variables, birth weight was predictive of bi‐iliac breadth only.ConclusionsMarkers of linear growth during both early and later development were associated with adult pelvic dimensions, whereas size at birth was poorly predictive. Efforts to reduce stunting in early life may facilitate the attainment of maximum potential growth for both height and the pelvis.

How reproducible are classical and new CT-pelvimetry measurements?

PurposeThe objective of this study was to assess the reliability and reproducibility of existing and new computed tomography (CT)-pelvimetry measurements. Material and methodsA retrospective cohort study of 63 women with a mean age of 33.9±5.2 (SD) years (range: 19–49 years) was conducted. Classical pelvimetry measurements were collected including the obstetric conjugate (OC), median transverse diameter (MTD), and interspinous diameter (ISD). Additionally, we used multiplanar reconstruction (MPR) mode to define two oblique planes: inlet pelvic plane (IPP) and mid-pelvic plane (MPP) and measure new pelvic parameters, including anteroposterior (APD), transverse diameters and circumference of both IPP and MPP (inletAPD, inletMTD, inletCIRC and midAPD, ISD, midCIRC, respectively). The reproducibility (intra- and inter-observer) of our results were assessed. Multivariate analyses using principal component analysis and clustering methods were conducted to analyze the association between pelvimetry measurements and identify patient sub-groups. ResultsAll linear measurements (OC, inletAPD, MTD, inletMTD, midAPD, and ISD) showed statistically “almost perfect” intra- and inter-observer correlation coefficients (range: 0.924–0.980). Circumferences (inletCIRC and midCIRC) showed statistically “almost perfect” intra- (range: 0.847–0.857) and inter-observer correlation coefficients (range: 0.923–0.957). The measurement of 6 pelvimetric parameters allowed determining three groups of pelvis size. ConclusionNew pelvic measurements have excellent reproducibility and are similar to the classical measurements, based on the MPR analysis of CT planes adjusted to the inner bony pelvis.

A novel measurement of pelvic floor cross-sectional area in older and younger women with and without prolapse

An increase in size of the aperture of the pelvis that must be spanned by pelvic floor support structures translates to an increase in the force on these structures. Prior studies have measured the bony dimensions of the pelvis, but the effect of changes in muscle bulk that may affect the size of this area are unknown. To develop a technique to evaluate the aperture size in the anterior pelvis at the level of the levator ani muscle attachments, and to identify age-related changes in women with and without prolapse. This was a technique development and pilot case-control study evaluating pelvic magnetic resonance imaging from 30 primiparous women from the Michigan Pelvic Floor Research Group MRI Data Base: 10 younger women with normal support, 10 older women with prolapse, and 10 older menopausal women without prolapse. Anterior pelvic area measurements were made in a plane that included the bilateral ischial spines and the inferior pubic point, approximating the level of the arcus tendineus fascia pelvis. Measurements of the anterior pelvic area, obturator internus muscles, and interspinous diameter were made by 5 independent raters from the Society of Gynecologic Surgeons Pelvic Anatomy Group who focused on developing pelvic imaging techniques, and evaluating interrater reliability. Demographic characteristics were compared across groups of interest using the Wilcoxon rank sum test, χ2, or Fisher exact test where appropriate. Multiple linear regression models were created to identify independent predictors of anterior pelvic area. Per the study design, groups differed in age and prolapse stage. There were no differences in race, height, body mass index, gravidity, or parity. Patients with prolapse had a significantly longer interspinous diameter, and more major (>50% of the muscle) levator ani defects when compared to both older and younger women without prolapse. Interrater reliability was high for all measurements (intraclass correlation coefficient= 0.96). The anterior pelvic area (cm2) was significantly larger in older women with prolapse compared to older (60±5.1 vs 53 ± 4.9, P= .004) and younger (60 ± 5.1 vs 52 ± 4.6, P= .001) women with normal support. The younger and older women with normal support did not differ in anterior pelvic area (52 ± 4.6 vs 53 ± 4.9, P= .99). After adjusting for race and body mass index, increased anterior pelvic area was significantly associated with the following: being an older woman with prolapse (β= 6.61 cm2, P= .004), and interspinous diameter (β= 4.52 cm2, P= .004). Older women with prolapse had the largest anterior area, suggesting that the anterior pelvic area is a novel measure to consider when evaluating women with prolapse. Interspinous diameter, and being an older woman with prolapse, were associated with a larger anterior pelvic area. This suggests that reduced obturator internus muscle size with age may not be the primary factor in determining anterior pelvic area, but that pelvic dimensions such as interspinous diameter could play a role. The measurements were highly repeatable. The high intraclass correlation coefficient indicates that all raters were able to successfully learn the imaging software and to perform measurements with high reproducibility.

A study of lesser pelvic parameters and their correlation with age by reformatted computed tomography in western Indian Gujarati female population

Abstract Background &amp; aims: Pelvic parameters vary according to age, race and population. The study is aimed at assessing female pelvic parameters using reformatted 3D CT images, compare the obtained values with other studies and correlate these parameters with age. Material &amp; Methods: Reformatted three-dimensional CT images were obtained from stored abdominopelvic computed tomography [CT] scan images. Image analysis software was used to determine various diameters of the lesser pelvis. Data were analysed to derive mean ± SD, SE, 95% Cl, paired t test and Pearson correlation test were used for comparison and correlation of variables. Results: Mean± standard deviation of obstetric conjugate diameter was 10.94±1.18 cm, transverse diameter of inlet was 12.46±0.81 cm, sagittal diameter of midplane wasl 1.74±0.80 cm, interspinous diameter was 9.78±0.75 cm, sagittal diameter of outlet was 8.99±1.02 cm and intertuberous diameter was 10.69±0.86. All the parameters except sagittal diameter of midplane and interspinous diameter showed correlation with age. Conclusion: The present study provides reference values for various pelvic parameters in western Indian Gujarati female population. Parameters obtained in present study vary greatly from previous studies from other populations. The results demonstrated that significant age-related changes occurred in pelvic inlet and outlet parameters.