Pelvic Tissue Research Articles

Episiotomy scar as a physiotherapeutic problem - case study

The article presents the case of a 28-year-old woman after vaginal delivery assisted by the use of a vacuum extractor. During delivery, the II° perineal rupture and pelvic floor tissue damage occurred. The patient came to the urogynecological physiotherapy practise because of major pain associated with the episiotomy scar. The article describes effects of physiotherapy.

A novel antibacterial biomaterial mesh coated by chitosan and tigecycline for pelvic floor repair and its biological performance.

The biomaterials composed of mammalian extracellular matrix (ECM) have a great potential in pelvic floor tissue repair and functional reconstruction. However, bacterial infection does cause great damage to the repair function of biomaterials which is the major problem in clinical utilization. Therefore, the development of biological materials with antimicrobial effect is of great clinical significance for pelvic floor repair. Chitosan/tigecycline (CS/TGC) antibacterial biofilm was prepared by coating CS/TGC nanoparticles on mammalian-derived ECM. Infrared spectroscopy, scanning electron microscopy, bacteriostasis circle assay and static dialysis methods were used to characterize the membrane. MTS assay kit and DAPI fluorescence staining were used to evaluate cytotoxicity and cell adhesion. The biocompatibility was assessed by subabdominal implantation model in goats. Subcutaneous antimicrobial test in rabbit back was used to evaluate the antimicrobial and repairing effects on the infected wounds in vivo. Infrared spectroscopy showed that the composite coating had been successfully modified. The antibacterial membrane retained the main structure of ECM multilayer fibers. In vitro release of biomaterials showed sustained release and stability. In vivo studies showed that the antibacterial biological membrane had low cytotoxicity, fast degradation, good compatibility, anti-infection and excellent repair ability.

Wound healing of the pelvic floor concerning pelvic organ prolapse – What do we know?

O prolapso de órgão pélvico (POP) é resultado do enfraquecimento dos tecidos de sustentação e de suspensão dessa região, incluindo os músculos levantadores do ânus, a fáscia endopélvica, os ligamentos e a parede vaginal. Sabe-se que os fatores de risco mais importantes para o POP, como gravidez, parto vaginal e aumento da pressão intra-abdominal, causam lesão nos tecidos do assoalho pélvico. Assim, é possível que um processo de cicatrização imperfeito desses tecidos possa afetar sua homeostase e contribuir para o desenvolvimento do POP. Dessa forma, o objetivo deste artigo é revisar a fisiologia da cicatrização de tecidos do assoalho pélvico e discutir os fatores que interferem nesse processo. Para isso, foi feita uma revisão da literatura na base de dados do MEDLINE até 2017. Percebeu-se que, assim como na pele, a cicatrização das lesões do assoalho pélvico ocorre em quatro fases (hemostasia, inflamação, proliferação e remodelação), porém a duração de cada fase é maior nas diferentes estruturas do assoalho pélvico. Além disso, a pressão constante no assoalho pélvico está associada ao aumento da atividade da colagenase, afetando negativamente a cicatrização, enquanto o estrogênio melhora as propriedades mecânicas do tecido estirado e parece ser benéfico para a cicatrização das lesões na parede vaginal. De acordo com a literatura, os músculos, nervos, ligamentos ou parede vaginal danificados não recuperam totalmente suas características prévias. Desse modo, conclui-se que uma cicatrização imperfeita no assoalho pélvico resulta em tecidos com composição e propriedades mecânicas alteradas, o que pode levar à incidência ou progressão do POP.

OBSTETRIC GYNECOLOGICAL SOCIETY IN Cologne.
 Meeting on January 7, 1892

Following Eberhart's demonstration of a patient with a vagus liver, Pelzer reported one non-operative case of cervical cancer that had spread to the pelvic tissue and vagina. In view of the previous observations, a small cotton swab soaked in a paste of Acidi arsenicosi cum Saccharo albo 1.0: 10.0 was placed on the ulcerative surface in the vagina. Bleeding and discharge decreased significantly, superficial ulceration disappeared.

Attitude of influenza to diseases of female genital organs

The influenza epidemic this year was not as widespread as it was 2 years ago, but for that it was much stronger and was accompanied by more severe complications. This also applies to the complications of her pelvic tissue diseases, as the author had to observe.

A joint kinematics driven model of the pelvic soft tissue artefact

When skin-markers trajectories are used in human movement analysis, compensating for their relative movement with respect to the underlying bone (soft tissue artefact, STA) is essential for accurate bone-pose estimation; information about the artefact is required in the form of a mathematical model. Such model, not available for pelvic artefacts, could allow pelvic STA compensation in routine gait analysis by embedding it in skeletal kinematics estimators and developing ad-hoc optimization problems for the estimate of subject-specific model parameters. It was developed as driven by adjacent body segment kinematics. Model architecture feasibility was tested; its compensation effectiveness was assessed evaluating the error in pelvic orientation after removing the modelled artefact from the measured one. Five volunteers with a wide body mass range (BMI: 22–37) underwent MRI scans to reconstruct subject-specific pelvic digital bone models. Multiple anatomical calibrations performed in different static postures, as occurring during walking and star-arc movements, registering the bone-models with points digitized through stereophotogrammetry over pelvic bony prominences, allowed to define the relevant poses of a pelvis-embedded anatomical coordinate system. Such approach allowed to measure STAs over several pelvic anatomical landmarks, for each posture and subject. Model parameters were estimated by minimizing the least squares difference between measured and modelled STAs. The measured STAs were appropriately modelled with subject-specific calibrations, both in terms of shape (correlation coefficient: median [inter-quartile-range]: 0.72 [0.36]) and amplitude (root mean square residual: 3.0 [3.2] mm). Consequently, the overall error in pelvic orientation vector (5.1 [4.4] deg) was reduced after removing the modelled artefacts (2.5 [1.9] deg).

Retrospective audit of inter-fraction motion for pelvic node radiotherapy in prostate cancer patients

IntroductionPelvic lymph nodes move independently to the prostate. When delivering radiotherapy to prostate and pelvic lymph nodes, daily inter- and intra-fraction anatomical changes need to be accounted for. Planning target volume (PTV) margins, grown from the pelvic lymph node clinical target volume need to be determined, to account for this variation in position. MethodsTwenty patients who had daily online image guided radiotherapy to prostate and pelvic lymph nodes between April and December 2018 were selected. Ten pre-treatment verification images using cone beam CT from each patient were registered to pelvic bone anatomy, prostate soft tissue or fiducial markers and pelvic lymph node soft tissue to assess the accuracy of treatment delivery. Population systematic and random errors and PTV margins were calculated. ResultsPTV margins of 0.4 cm, 0.4 cm and 0.7 cm left–right (LR), superior–inferior (SI) and anterior–posterior (AP) respectively were derived for the pelvic lymph nodes when registering to prostate. PTV margins of 0.3 cm, 0.2 cm and 0.4 cm LR, SI and AP respectively were derived for the pelvic lymph nodes when registering to bone. There was a posterior systematic shift of the prostate during the treatment course. ConclusionThere is differential motion of pelvic lymph nodes to prostate and in the era of prostate and pelvic radiotherapy for patients with node positive prostate cancer; there is increasing importance in the accuracy of dose delivery to the involved lymph node. Hence, this group of patients may benefit from personalised radiotherapy PTV margins, especially if the involved pelvic lymph node is within the anterior part of the clinical target volume. Implications for practiceOptimisation of dose delivery to the pelvic lymph nodes when prioritising the prostate in prostate and pelvic lymph node image guided radiotherapy.

AUTOPSY FEATURES AT THE ACUTE DESTRUCTIVE PANCREATITIS

In all variants of the destructive form of pancreatitis, the involvement of adipose tissue of both para-pancreatic and distant localization was noted. In this case, it is necessary to improve the pathological diagnosis of acute destructive pancreatitis. The aim of the study was to develop new techniques for postmortem examination of those who died from complications of acute pancreatitis. Pathological studies were supplemented by the methods proposed by the authors, which made it possible to clarify the spread of the infectious agent through the retroperitoneal tissue. The scheme proposed by the authors for recording changes in the tissue of the pancreas and surrounding tissues after a contrast study made it possible to clarify the main ways of propagation of the purulent-necrotic process along the retroperitoneal tissue. The results of postmortem examination of 67 deaths from complications of acute pancreatitis are presented. Based on the study, 5 types of acute destructive pancreatitis were identified. In type I, the pathological process involves the right half of the retroperitoneal tissue, including the mesentery root of the small intestine, the para-pancreatic region, the right para-kidney and sub-hepatic space. The second type is characterized by the presence of inflammatory and destructive changes in the fiber of the right lateral canal, the actual retroperitoneal space on the right and the mesentery root of the transverse colon. Purulent-necrotic changes in para-pancreatic, left perineal tissue, mesentery of the transverse colon, also in peritoneum were typical for type III acute destructive pancreatitis. For type IV disease, in addition to areas of involvement as in type III, involvement of the pelvic tissue and the left sections of the retroperitoneal space itself were noted. The spread of the infectious agent to both the right and left parts of the retroperitoneal tissue was defined as type V acute destructive pancreatitis.

Abdominal and pelvic adipose tissue distribution and risk of prostate cancer recurrence after radiation therapy.

Fat distribution varies between individuals of similar body mass index (BMI). We hypothesized that visceral obesity is more strongly associated with poor prostate cancer outcomes than overall obesity defined by BMI. We quantified abdominal visceral and subcutaneous fat area (VFA and SFA), and pelvic periprostatic adipose tissue area (PPAT), using computed tomography scans from radiation-treated prostate cancer patients at the Durham North Carolina Veterans Administration Hospital. Multivariable-adjusted Cox regression examined associations between each adiposity measure and risk of recurrence, overall and stratified by race and receipt of androgen deprivation therapy (ADT). Of 401 patients (59% black) treated from 2005 to 2011, 84 (21%) experienced recurrence during 9.3 years median follow-up. Overall, obesity defined by BMI was not associated with recurrence risk overall or stratified by race or ADT, nor was any measure of fat distribution related to the risk of recurrence overall or by race. However, higher VFA was associated with increased risk of recurrence in men who received radiation only (hazard ratio [HR], 1.79; 95% confidence interval [CI], 0.87-3.66), but inversely associated with recurrence risk in men treated with radiation and ADT (HR, 0.49; 95% CI, 0.24-1.03; P-interaction = .002), though neither association reached statistical significance. Similar patterns of ADT-stratified associations were observed for PPAT and SFA. Associations between abdominal and pelvic adiposity measures and recurrence risk differed significantly by ADT receipt, with positive directions of association observed only in men not receiving ADT. If confirmed, our findings suggest that obesity may have varying effects on prostate cancer progression risk dependent on the hormonal state of the individual.

Head, Neck, Trunk, and Pelvis Tissue Mass Predictions for Older Adults using Anthropometric Measures and Dual-Energy X-Ray Absorptiometry

Background: Regression equations using anthropometric measurements to predict soft (fat mass [FM], lean mass [LM], wobbling mass [WM]) and rigid (bone mineral content [BMC]) tissue masses of the extremities and core body segments have been developed for younger adults (16-35 years), but not older adults (36-65 years). Tissue mass estimates such as these would facilitate biomechanical modeling and analyses of older adults following fall or collision-related impacts that might occur during sport and recreational activities. Purpose: The purpose of this study was to expand on the previously established tissue mass prediction equations of the head, neck, trunk, and pelvis for healthy, younger adults by generating a comparable set of equations for an older adult population. Methods: A generation sample (38 males, 38 females) was used to create head, neck, trunk, and pelvis tissue mass prediction equations via multiple linear stepwise regression. A validation sample (13 males, 12 females) was used to assess equation accuracy; actual tissue masses were acquired from manually segmented full body Dual-Energy X-ray Absorptiometry scans. Results: Adjusted R2 values for the prediction equations ranged from 0.326 to 0.949, where BMC equations showed the lowest explained variances overall. Mean relative errors between actual and predicted masses ranged from –2.6% to 6.1% for trunk LM and FM, respectively. All actual tissue masses except head BMC (R2 = 0.092) were significantly correlated to those predicted from the equations (R2 = 0.403 to 0.963). Conclusion: This research provides a simple and effective method for predicting head, neck, trunk, and pelvis tissue masses in older adults that can be incorporated into biomechanical models for analyzing sport and recreational activities. Future work with this population should aim to improve core segment BMC predictions and develop equations for the extremities.

Climacturia After Radical Prostatectomy: MRI-Based Predictors

BackgroundAfter radical prostatectomy (RP), climacturia is a prevalent and distressing problem. To date, no specific predictors have been identified. AimIn this analysis, we sought to find associated pelvic magnetic resonance imaging (MRI) parameters. MethodsWe identified all men in our departmental database who (i) had climacturia post-RP, ≥3 episodes; (ii) underwent a pre-RP endorectal MRI; (iii) had no radiation or androgen deprivation therapy (ADT). Soft tissue and bony dimensions were measured by 2 raters blinded to clinical and pathological data. OutcomesMRI parameters included the following: maximum height, width, and depth of prostate, prostate volume, urethral width and length, lower conjugate of pelvis, bony femoral width, outer and inner levator distances and thickness. Point-biserial correlations were run on univariate associations. Logistic regression was used for the multivariable model. Results194 consecutive pre-RP MRI studies were reviewed (56 men with and 138 without climacturia). Mean age was 60 ± 7 years, average time post-RP at assessment, 7 ± 7 months. Of MRI parameters, urethral width (r = 0.13, P = .03) and lower conjugate (r = 0.12, P = .05) were associated with presence of persistent climacturia. 2 others met criteria for multivariable analysis, prostate depth and outer levator distance. Of the non-MRI parameters, none were significantly related to climacturia and only body mass index (BMI) met criteria for multivariable analysis. On multivariable analysis, only urethral width was associated with climacturia (OR = 1.23, 95% CI: 1.01–1.49, P = .04); the wider the urethra, greater the chance of climacturia. Clinical ImplicationsImproved ability to predict the occurrence of orgasm-associated incontinence in the preoperative setting. Strengths and LimitationsLimitations include the fact that the MRI endorectal probe may have distorted pelvic tissues during imaging and that our study population size was small. However, prospective data collection, blinded measurements by 2 trained readers, and rigorous statistical analysis should be considered strengths. ConclusionBy identifying preoperative risk factors, such as urethral width on MRI, we may be able to better understand the pathophysiology of this condition and furthermore may permit us to better counsel men regarding this postoperative outcome.Sullivan JF, Ortega Y, Matsushita K, et al. Climacturia After Radical Prostatectomy: MRI-Based Predictors. J Sex Med 2020;17:1723–1728.

Estimation of secondary cancer risk after radiotherapy in high-risk prostate cancer patients with pelvic irradiation.

We aimed to estimate the risk of secondary cancer after radiotherapy (RT) in high‐risk prostate cancer (HRPC) patients with pelvic irradiation. Computed tomography data of five biopsy‐proven HRPC patients were selected for this study. Two different planning target volumes (PTV1 and PTV2) were contoured for each patient. The PTV1 included the prostate, seminal vesicles, and pelvic lymphatics, while the PTV2 included only the prostate and seminal vesicles. The prescribed dose was 54 Gy for the PTV1 with a sequential boost (24 Gy for the PTV2). Intensity‐modulated RT (IMRT) and volumetric modulated arc therapy (VMAT) techniques were used to generate treatment plans with 6 and 10 MV photon energies with the flattening filter (FF) or flattening filter‐free (FFF) irradiation mode. The excess absolute risks (EARs) were calculated and compared for the bladder, rectum, pelvic bone, and soft tissue based on the linear‐exponential, plateau, full mechanistic, and specific mechanistic sarcoma dose‐response model. According to the models, all treatment plans resulted in similar risks of secondary bladder or rectal cancer and pelvic bone or soft tissue sarcoma except for the estimated risk of the bladder according to the full mechanistic model using IMRT(6MV;FF) technique compared with VMAT techniques with FFF options. The overall estimation of EAR indicated that the radiation‐induced cancer risk due to RT in HRPC was lower for bladder than the rectum. EAR values ranged from 1.47 to 5.82 for bladder and 6.36 to 7.94 for rectum, depending on the dose–response models used. The absolute risks of the secondary pelvic bone and soft tissue sarcoma were small for the plans examined. We theoretically predicted the radiation‐induced secondary cancer risk in HRPC patients with pelvic irradiation. Nevertheless, prospective clinical trials, with larger patient cohorts with a long‐term follow‐up, are needed to validate these model predictions.

Cellular senescence: A pathogenic mechanism of pelvic organ prolapse (Review).

Pelvic organ prolapse (POP) is a common symptom of pelvic floor disorders which is characterized by the descent of the uterus, bladder or bowel from their normal anatomical position towards or through the vagina. Among the older population, the incidence of POP increases with age. It is becoming necessary to recognize that POP is a degenerative disease that is correlated with age. In recent years, studies have been performed to improve understanding of the cellular and molecular mechanisms concerning senescent fibroblasts in pelvic tissues, which contribute to the loss of structure supporting the pelvic organs. These mechanisms can be classified into gene and mitochondrial dysfunctions, intrinsic senescence processes, protein imbalance and alterations in stem cells. The present review provides an integrated overview of the current research and concepts regarding POP, in addition to discussing how fibroblasts can be targeted to evade the negative impact of senescence on POP. However, it is probable that other mechanisms that can also cause POP exist during cell senescence, which necessitates further research and provides new directions in the development of novel medical treatment, stem cell therapy and non-surgical interventions for POP.

Algorithms for the surgical management of benign and malignant presacral tumors

Presacral (or retrorectal) tumors are rare tumors which arise in the space between the mesorectum and the sacrum. This space contains tissues derived from all three germ cell layers and from which presacral tumors may arise. Presacral tumors can be broadly categorized as congenital or acquired, and benign or malignant, and morphologically they may be cystic, solid or heterogeneous. This group of tumors are often asymptomatic and may be identified incidentally on clinical examination or pelvic imaging. Magnetic resonance imaging (MRI) is the gold standard imaging modality as it can accurately demonstrate the relationship between the tumor and adjacent structures and helps to delineate between benign and malignant lesions. PET/CT can be useful when assessing malignant and indeterminate lesions in order to identify aggressive pathology and exclude metastatic disease. Radiologically-guided percutaneous biopsy of malignant or indeterminate tumors can be performed safely in order to obtain a histological diagnosis and determine whether there is a role for adjuvant therapies. Surgery is the mainstay of treatment of presacral tumors. Benign lesions can be monitored with regular MRI, particularly smaller lesions which are asymptomatic. If resection is required, benign lesions can often be “shelled out” with preservation of adjacent structures and therefore function, whereas malignant tumors generally require radical excision with wide margins and sacrifice of involved pelvic organs or soft tissues, bone and neurovascular structures.

Extensive Extramedullary Hematopoiesis in Thalassemia

We report the case of a 45-year-old man with thalassemia major referred for a bone scan as a workup for generalized bone pain. Tc-MDP SPECT CT showed multiple elongated soft tissue masses along the inner aspects of ribs and along both sides of dorsal spine with calcification and mild tracer uptake. There was also a large lobulated presacral soft tissue mass displacing the bladder and involving the adjacent pelvic bone. Biopsy of mildly avid tracer uptake in pelvic soft tissue mass was extramedullary hematopoiesis confirmed by biopsy.

Quantitative CT measurement of left colonic and pelvic mesenteric adipose volume in radiation proctitis.

The edema of left colonic and pelvic mesenteric adipose tissues has long been recognized in surgery as a characteristic feature of radiation proctitis (RP). However, the correlation between mesenteric adipose volume and RP has not been extensively clarified. The purpose of this study was thus to assess the variation of left colonic and pelvic mesenteric adipose volume in RP. From March 2013 to June 2015, the data of 52 patients with locally advanced rectal cancer who underwent neoadjuvant chemoradiotherapy, including 23 patients with RP and 29 with non-RP (nRP), were retrieved. The mesenteric adipose volume was quantified via a computed tomography (CT) reconstruction method. Corresponding analyses were conducted to observe the correlation between the relative change of mesenteric adipose volume and the thickening degree of the rectal wall. The baseline data of the RP group and the nRP group were comparable. There was no significant difference in the relative change of the left colonic mesenteric adipose volume in each vertebral space from the third lumbar vertebra to the first sacral vertebra before and after radiotherapy. The relative change of pelvic mesenteric adipose volume (ΔVp%) was notably higher in the RP group compared to the nRP group. With a ΔVp% cutoff value of 3.67%, the sensitivity and specificity for the diagnosis of RP were 65.2% and 86.2%, respectively. According to the correlation analysis, ΔVp% in the RP group was significantly correlated with the thickening degree of the rectal wall after radiotherapy (r=0.47, P=0.024). The increment of the relative change of pelvic mesenteric adipose volume quantitatively measured by CT can be clinically useful in identifying RP.

Computer-Aided Biomedical Imaging of Periiliac Adipose Tissue Identifies Perivascular Fat as a Marker of Disease Complexity in Patients with Lower Limb Ischemia

The aim of the study was to develop a semi-automated, computer-aided imaging technique to quantify the amount and distribution of perivascular fat at the level of the iliac arteries (periiliac adipose tissue—PIAT), and to investigate the association of this new computer-aided imaging biomarker with other biomedical imaging biomarkers, which characterize the pelvic adipose tissue (SAT—subcutaneous adipose tissue; VAT—visceral adipose tissue). We included 34 patients with peripheral arterial disease, in whom the volumes of PIAT, SAT and VAT were quantified using a dedicated software, at the level of right and left iliac arteries. Median value of PIAT was five milliliters. Patients with PIAT > five milliliters were in more advanced Fontaine classes, with more complex arterial lesions, compared to those with low PIAT (<5 mL) (p < 0.0001). PIAT volumes presented a gradual increase with the Trans-Atlantic Inter-Society Consensus (TASC) class (2.57 +/− 1.98 in TASC A, 4.65 +/− 1.63 in TASC B, 8.79 +/− 1.99 in TASC C and 13.77 +/− 2.74 in TASC D). The distribution of PIAT between the left and right iliac axis was quasi-uniform (correlation between right and left PIAT: r = 0.46, p = 0.005). Linear regression analysis showed that the mean PIAT volume was correlated with VAT (r = 0.38, p = 0.02), but not with the SAT at the level of iliac artery origin (r = 0.16, p = 0.34). PIAT may represent a novel biomedical imaging derived biomarker, which characterizes the distribution of adipose tissue in the pelvic area and may serve as an indicator of the severity and complexity of lower limb ischemia.

Extralevator abdominoperineal excision for advanced low rectal cancer: Where to go.

Since its introduction, extralevator abdominoperineal excision (ELAPE) in the prone position has gained significant attention and recognition as an important surgical procedure for the treatment of advanced low rectal cancer. Most studies suggest that because of adequate resection and precise anatomy, ELAPE could decrease the rate of positive circumferential resection margins, intraoperative perforation, and may further decrease local recurrence rate and improve survival. Some studies show that extensive resection of pelvic floor tissue may increase the incidence of wound complications and urogenital dysfunction. Laparoscopic/robotic ELAPE and trans-perineal minimally invasive approach allow patients to be operated in the lithotomy position, which has advantages of excellent operative view, precise dissection and reduced postoperative complications. Pelvic floor reconstruction with biological mesh could significantly reduce wound complications and the duration of hospitalization. The proposal of individualized ELAPE could further reduce the occurrence of postoperative urogenital dysfunction and chronic perianal pain. The ELAPE procedure emphasizes precise anatomy and conforms to the principle of radical resection of tumors, which is a milestone operation for the treatment of advanced low rectal cancer.

Elastin homeostasis is altered with pelvic organ prolapse in cultures of vaginal cells from a lysyl oxidase-like 1 knockout mouse model.

Pelvic organ prolapse (POP) decreases quality of life for many women, but its pathophysiology is poorly understood. We have previously shown that Lysyl oxidase‐like 1 knockout (Loxl1 KO) mice reliably prolapse with age and increased parity, similar to women. Both this model and clinical studies also indicate that altered elastin metabolism in pelvic floor tissues plays a role in POP manifestation, although it is unknown if this is a cause or effect. Using Loxl1 KO mice, we investigated the effects of genetic absence of Loxl1, vaginal parity, and presence of POP on the expression of genes and proteins key to the production and regulation of elastic matrix. Cultured cells isolated from vaginal explants of mice were assayed with Fastin for elastic matrix, as well as RT‐PCR and Western blot for expression of genes and proteins important for elastin homeostasis. Elastin synthesis significantly decreased with absence of LOXL1 and increased with parity (p < .001), but not with POP. Cells from prolapsed mice expressed significantly decreased MMP‐2 (p < .05) and increased TIMP‐4 (p < .05). The results suggest changes to elastin structure rather than amounts in prolapsed mice as well as poor postpartum elastin turnover, resulting in accumulation of damaged elastic fibers leading to abnormal tropoelastin deposition. POP may thus, be the result of an inability to initiate the molecular mechanisms necessary to clear and replace damaged elastic matrix in pelvic floor tissues after vaginal birth.

Pelvic floor shape variations during pregnancy and after vaginal delivery

Background and objectiveStrong evidence suggests that pelvic soft tissues soften during pregnancy to facilitate vaginal delivery while protecting against maternal birth injury. We hypothesized that these adaptations likely result in changes to the shape of the pelvic floor. Thus, this study aimed to compare midsagittal pelvic floor shapes from MRIs of nulliparous, gravid, and vaginally parous women using statistical shape modeling. MethodsA retrospective study of 22 nulliparous, 29 gravid (vaginally nulliparous), and 18 vaginally parous women who underwent pelvic MRI was performed. The pelvic floor was segmented from pubic symphysis to coccyx as a 2D polyline in the midsagittal plane. Once corresponding landmarks were computed and the variances between them determined by principal component analysis, the principal component scores were calculated for modes that explained variance greater than noise. These became the dependent variables in a MANOVA with univariate ANOVAs, linear regressions, and Benjamini-Hochberg corrections post hoc. Two initial statistical shape analyses were conducted to analyze differences based on gestational age (1st/2nd vs 3rd trimester) and vaginal parity (VP1 vs VP2-4). There were significant differences based on gestational age, but not vaginal parity. Thus, the final statistical shape analysis evaluated pelvic floor shapes of nulliparous, 3rd trimester gravid, and all vaginally parous subjects. ResultsIn the final analysis, six modes described variance—a measure of shape variability—greater than noise. Groups differed significantly for modes 1, 2, and 4 (p < 0.001, p = 0.021, and p = 0.015, respectively) and only differed between the nulliparous and gravid groups (p < 0.001, p = 0.018, and p = 0.012, respectively). Anatomically, these modes described levator plate relaxation and level III support protrusion in gravid compared to nulliparous subjects while the parous group straddled the other two. ConclusionsThe shape of the pelvic floor changes significantly during pregnancy and some of those changes are present after vaginal delivery. The fact that the nulliparous and gravid groups differ while the parous is similar to both suggests that some parous women regain their nulliparous shape after pregnancy and delivery while others do not. This indicates that remodeling during pregnancy and/or injury during vaginal delivery can have lasting effects on the pelvic floor.