Tridimensional sonographic anatomical changes on pelvic floor muscle according to the type of delivery

Feasibility and reproducibility of new technique for measurement of transverse diameter of levator ani muscle hiatus using two-dimensional transperineal ultrasound in nulliparous women with term pregnancy

OBJECTIVES

The aim of the present study was two-fold. Firstly, we aimed to develop and describe a technique for measurement of the transverse diameter (TD) of the levator ani muscle (LAM) hiatus in the coronal view using two-dimensional (2D) transperineal ultrasound (TPUS) in nulliparous women with a term pregnancy. Secondly, we aimed to evaluate the feasibility and reproducibility of 2D-TPUS assessment of LAM hiatal TD and assess intermethod agreement between 2D-TPUS and three-dimensional (3D) TPUS measurement of TD in the axial plane, which is considered the gold standard in nulliparous women with term pregnancy.

METHODS

We recruited a group of nulliparous women with term pregnancy before the onset of labor. The study was conducted in two phases: Phase 1 involved developing and describing the 2D-TPUS technique for measuring LAM hiatal TD, and Phase 2 focused on assessing the technique's feasibility, reproducibility and intermethod agreement with 3D-TPUS measurement of LAM hiatal TD. In Phase 1, we enrolled 30 women. Each woman underwent acquisition of a 3D-TPUS volume, which was analyzed using multiplanar mode to identify and determine the appearance of the lateral borders of the LAM in the coronal plane, at the level of the plane of minimal hiatal dimensions. These borders were used as landmarks for TD measurement. Additionally, we measured the distance between the plane used for TD measurement and the center of the urethra in the axial view. In Phase 2, we recruited 100 women. Each woman underwent acquisition of three 2D-TPUS videoclips in the coronal plane, each encompassing a sweep of the entire LAM hiatus, and a 3D volume, all obtained during rest. On the 2D videoclips, TD was measured twice by one operator and once by another operator. In the 3D volume, TD was measured once, by one operator, in the axial plane; this measurement was considered the gold standard. Each operator was blinded to all other measurements during their assessments. We analyzed intraobserver and interobserver reproducibility and performed an intermethod (2D vs 3D) comparison. Bland-Altman analysis was conducted, and Levene's W0 test and Student's t-test were performed to explore clinical factors that might contribute to systematic differences.

RESULTS

In Phase 1, we identified successfully the landmarks denoting the lateral borders of the LAM hiatal TD in the coronal view. These appeared as two symmetrical hypoechogenic indentations located at the inner border of the hyperechogenic structure of the LAM, at the point of maximum distance between the two sides of the LAM. The distance between the urethra and the plane where TD should be measured using 3D-TPUS in the axial plane had a median of 4 mm and varied from 0 to 9 mm. This enabled us to describe a method for assessing LAM hiatal TD in the coronal plane using 2D-TPUS. In Phase 2, LAM hiatal TD was measured successfully in all 2D and 3D acquisitions from the entire group of 100 women. The analyses for intraobserver and interobserver reproducibility and the intermethod comparison (2D vs 3D) revealed almost perfect agreement in TD measurements using 2D-TPUS, with intraclass correlation coefficients of 0.95 (95% CI, 0.92-0.96), 0.87 (95% CI, 0.78-0.92) and 0.85 (95% CI, 0.78-0.90), respectively. The average differences between measurements were 0.1 mm for intraobserver, 1.0 mm for interobserver and 0.2 mm for intermethod repeatability. No systematic differences were observed in any of the measurement sets, except in the interobserver analysis, although this difference was clinically not significant (38.2 vs 37.2 mm, P = 0.01). None of the examined clinical factors (maternal body mass index and maternal age) exhibited a statistically significant impact on intraobserver, interobserver or intermethod reliability.

CONCLUSIONS

Utilizing our technique, described herein, to measure the LAM hiatal TD in the coronal view using 2D-TPUS is not only feasible but also highly reproducible and accurate in nulliparous women with term pregnancy. Moreover, it yields measurements that are comparable to those obtained in the reconstructed axial plane generated by 3D-TPUS. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.

Obstetric risk factors for levator ani muscle avulsion: A systematic review and meta-analysis

OBJECTIVES

Women have a 11% lifetime risk of undergoing surgery for vaginal prolapse. Levator ani muscle (LAM) avulsion is one etiological factor associated with primary and recurrent pelvic organ prolapse. Pelvic organ prolapse has been shown to greatly affect the quality of life and well-being of women. Conduct a meta-analysis identifying risk factors associated with LAM avulsion recognised on transperineal ultrasound (TPUS) or magnetic resonance imaging (MRI) in primiparous women after vaginal birth.

STUDY DESIGN

OVID Medline, Embase and the Cochrane Library from inception to January 2021 were searched. Review Manager 5.3 (The Cochrane Collaboration) was used to analyse data. Odds ratios (OR) with 95% confidence intervals (95% CIs) were calculated. The heterogeneity among studies was calculated using the I2statistic.

RESULTS

Twenty-five studies were eligible for inclusion (n = 9333 women). Major LAM avulsion was diagnosed in an average of 22 % (range 12.7-39.5 %) of cases. Twenty-two studies used TPUS and three used MRI to diagnose avulsion. Modifiable and non-modifiable risk factors were identified. Significant predictors identified were forceps (OR 6.25 [4.33 - 9.0]), obstetric anal sphincter injuries (OR 3.93 [2.85-5.42]), vacuum (OR 2.41 [1.40-4.16]), and maternal age (OR 1.06 [1.02-1.10]).

CONCLUSIONS

This is the first meta-analysis of both modifiable and non-modifiable risk factors associated with LAM avulsion. This information could be used to develop a clinically applicable risk prediction model to target postnatal women at risk of LAM avulsion with a view to prevent the onset of pelvic floor organ prolapse.

Effect of different electrostimulation currents on female urinary incontinence: A protocol of a randomized controlled trial

INTRODUCTION

Urgency urinary incontinence (UUI) is characterized by involuntary urine leakage immediately after reporting of sudden, compelling desire to void. Electrostimulation and non-invasive neuromodulation have been considered as the first and third line of UUI treatment but there is a lack of consensus on which parameters are more efficient. Thus, this study aims to compare the effect of low versus medium frequency currents on urinary incontinence severity and quality of life in women with UUI complains.

METHODS

It will be a randomized controlled trial with 5 arms, double-blinded (outcome assessor and statistician). The study was approved by the Research Ethics Committee (CAAE: 11479119.9.0000.5406) and has been prospectively registered on the Brazilian Registry of Clinical Trials (RBR-8bkkp6). Concerning, double-blind process, the blinded assessor will be responsible for evaluate primary and secondary outcomes at baseline and follow-up without information about allocation and the statistician will perform analyses without information about group codification. One hundred and five participants will be randomized to receive: (1) Transcutaneous tibial nerve stimulation-low frequency, (2) Transcutaneous tibial nerve stimulation-high frequency, (3) Aussie median frequency, (4) Interferencial median frequency or (5) High voltage stimulation. The application will be performed during 20 sessions of 45-minutes, twice a week for 10 weeks, in groups of maximum 5 participants. The participants will be evaluated before treatment (baseline- 0 week), during the treatment (5 weeks) and after the last treatment session (10 weeks). The primary outcomes measures will be UI severity and quality of life, and the secondary outcome will be pelvic floor strength. Statistical analysis will be performed using SPSS software version 24.0 for Windows (IBM Corp., Armonk, N.Y., USA). The variables will be described by the mean and 95% confidence interval. The distribution of normality will be analyzed by the Shapiro-Wilk test. ANOVA for repeated measures will be performed. Mauchly's test the hypothesis of sphericity and when if this violated the hypotheses, the analyses will be based on the Greenhouse-Geisser test. Peer-to-peer comparisons will be performed using the Bonferroni Post-Hoc test. The significant level adopted will be 5% (p ≤ 0.05).

CONCLUSION

This study will enhance knowledge about effect of different neuromodulation currents in the improvement of UUI.

Risk factors of pelvic floor muscle strength in south Chinese women: a retrospective study

Objectives

To evaluate pelvic floor muscle strength using surface electromyography and risk factors for pelvic floor muscle strength in the early postpartum period.

Methods

This retrospective study included 21,302 participants who visited Fujian Maternity and Child Health Hospital from September 2019 to February 2022. All participants were assessed by medical professionals for general information and surface electromyography.

Results

Univariate analysis indicated that age was inversely related to tonic and endurance contractions. In contrast, all the other variables, including education level, body mass index, neonatal weight, and number of fetuses, had a positive impact on rapid, tonic, and endurance contractions. Likewise, parity was also positively associated with rapid contractions. In addition, compared with vaginal delivery, cesarean section delivery had a protective effect on the amplitude of the three types of contractions. Stepwise regression analysis showed that both age and neonatal weight had a negative linear relationship with the amplitude of rapid, tonic and endurance contractions. In contrast, the amplitude of rapid, tonic and endurance contractions significantly increased as body mass index, parity (≤ 3), education level and gestational weight gain (endurance contractions only) increased. Participants with cesarean section delivery showed positive effects on rapid, tonic, and endurance contractions compared to participants with vaginal delivery.

Conclusions

We found that age, neonatal weight, vaginal delivery, episiotomy, and forceps delivery were risk factors for pelvic floor muscle strength; in contrast, body mass index, parity (≤ 3) and gestational weight gain had a positive relationship with pelvic floor muscle strength.

Levator ani avulsion: a Systematic evidence review (LASER)

BACKGROUND

There is variation in the reported incidence rates of levator avulsion (LA) and paucity of research into its risk factors.

OBJECTIVE

To explore the incidence rate of LA by mode of birth, imaging modality, timing of diagnosis and laterality of avulsion.

SEARCH STRATEGY

We searched MEDLINE, EMBASE, CINAHL, AMED and MIDIRS with no language restriction from inception to April 2019.

STUDY ELIGIBILITY CRITERIA

A study was included if LA was assessed by an imaging modality after the first vaginal birth or caesarean section. Case series and reports were not included.

DATA COLLECTION AND ANALYSIS

RevMan v5.3 was used for the meta-analyses and SW SAS and STATISTICA packages were used for type and timing of imaging analyses.

RESULTS

We included 37 primary non-randomised studies from 17 countries and involving 5594 women. Incidence rates of LA were 1, 15, 21, 38.5 and 52% following caesarean, spontaneous, vacuum, spatula and forceps births, respectively, with no differences by imaging modality. Odds ratio of LA following spontaneous birth versus caesarean section was 10.69. The odds ratios for LA following vacuum and forceps compared with spontaneous birth were 1.66 and 6.32, respectively. LA was more likely to occur unilaterally than bilaterally following spontaneous (P < 0.0001) and vacuum-assisted (P = 0.0103) births but not forceps. Incidence was higher if assessment was performed in the first 4 weeks postpartum.

CONCLUSIONS

LA incidence rates following caesarean, spontaneous, vacuum and forceps deliveries were 1, 15, 21 and 52%, respectively. Ultrasound and magnetic resonance imaging were comparable tools for LA diagnosis.

TWEETABLE ABSTRACT

Levator avulsion incidence rates after caesarean, spontaneous, vacuum and forceps deliveries were 1, 15, 21 and 52%, respectively.

The correlation between the type of forceps application and the rate of levator ani muscle avulsion: A prospective cohort study

OBJECTIVES

The association between the use of forceps and levator ani muscle (LAM) avulsion seems to be clear-cut. However, whether the lesion is due to the mechanical trauma yielded by the instrument or to the intrinsic complexity of this type of delivery, is yet to be determined. This study aims at determining the difference in LAM avulsion rate between Kielland rotational forceps and non-rotational forceps.

STUDY DESIGN

Prospective observational study with 94 nulliparous women with forceps-assisted deliveries (FD) between July 2015 and January 2016. 3D-TpUS was performed 6 months after every patient's delivery, during which LAM avulsion, and levator hiatus area and anteroposterior and transverse diameters were assessed.

RESULTS

A total of 89 nulliparous were studied, comprising 27 rotational-FD, and 62 non-rotational-FD. No differences in obstetric, intrapartum, or neonatal characteristics were observed between study groups. There were no statistically significant differences in the presence of avulsion between cases of rotational forceps (44.4% vs 35.5%, OR: 1.5 [0.6-3.6]), correction of asinclitism of the fetal head (34.4% vs. 40.4% OR: 0.8 [0.3-1.9]) or station (midforceps: 32.8% vs low forceps: 50.0% OR: 2.0 [0.8-5.1]).

CONCLUSIONS

We have not observed differences in the LAM-avulsion rate between rotational forceps and non-rotational forceps performed by highly experienced personnel in instrumental deliveries.

Anatomic and functional evaluation of the levator ani muscle after an obstetric anal sphincter injury

PURPOSE

To study the relationship between symptoms of anal incontinence (AI) and the anatomy and functionality of the levator ani muscle in women with a history of obstetric anal sphincter injury (OASI).

METHODS

This is a cohort study including patients with OASI from 2013 to 2016. Patients were assessed by a physical examination, endoanal ultrasound using Starck Scale, perineometry and 4D transperineal ultrasound. AI in all patients was measured with the Wexner scale. Correlation between variables has been analyzed in these patients.

RESULTS

72 patients were analyzed: 28 with a IIIA degree tear, 26 with a IIIB, 13 with a IIIC and 5 with a IV. 38 patients showed a residual anal sphincter (AS) defect on endoanal ultrasound with an average Starck score of 6.5 ± 3.7. 21 patients expressed AI, with an average Wexner score of 4.1 ± 2.4. In 27 (37.5%) patients, a levator ani avulsion was observed: 17 unilateral and 10 bilateral. Patients with a levator ani defect had weaker pelvic floor muscle (PFM) function. These differences were statistically significant with perineometry (p = 0.01 and p = 0.03) but not for the Oxford test (p = 0.08). Patients with a residual AS defect as well as an injury to the levator ani muscle expressed greater AI symptomatology than patients with residual sphincter injury who maintain the integrity of the levator ani: Wexner 4.9 0.9 vs 3.3 1 (p = 0.02).

CONCLUSIONS

The PFM has correlation with AI symptom development in patients with a history of OASI. Therefore, we suggest a key role of anatomical and functional assessments of the levator ani muscle in these patients.

Delivery mode and the risk of levator muscle avulsion: a meta-analysis

INTRODUCTION AND HYPOTHESIS

Female pelvic organ prolapse (POP) is a common condition, with a lifetime risk for surgery of 10-20%. Pregnancy and childbirth are the commonest modifiable risk factors for POP, and avulsion of the levator ani muscle is likely to be an etiological factor. Avulsion is more common in instrumental delivery. However, we were unable to identify a meta-analysis on this issue. Our aim was to perform a systemic review and quantitative meta-analysis of the prevalence of avulsion relative to delivery mode.

METHODS

Four electronic databases (MEDLINE, PubMed, Embase, and Google Scholar) were searched for studies published between 1991 and 1 October 2018 without language restrictions.

RESULTS

Twenty studies met inclusion criteria, and 14 were prospective. Seventeen used sonographic techniques; three were magnetic resonance (MR) studies. For this review, three comparisons were performed: forceps vs. vacuum (9 studies), forceps vs. normal vaginal delivery (NVD) (12 studies), and vacuum vs. NVD (12 studies). The first meta-analysis showed an increased risk for avulsion following forceps compared with vacuum, with an odds ratio (OR) of 4.57 and confidence interval (CI) 3.21-6.51, p < 0.001. The second showed an increased risk for avulsion following forceps compared with NVD, with an OR of 6.94 (4.93-9.78), p < 0.001. The third showed no significant increased risk for avulsion following vacuum compared with NVD, with an OR of 1.31 (1.00-1.72), p = 0.051.

CONCLUSIONS

Forceps is a strong risk factor for avulsion, with an OR of 6.94 (4.93-9.78) compared with NVD and an OR of 4.57 (3.21-6.51) compared with vacuum birth.

Fundal pressure in second stage of labor (Kristeller maneuver) is associated with increased risk of levator ani muscle avulsion

OBJECTIVE

To investigate the association between application of fundal pressure during the second stage of labor (Kristeller maneuver) and the risk of levator ani muscle (LAM) injury.

METHODS

This was a prospective case-control study of women recruited immediately after their first vaginal delivery in our university hospital between March 2014 and September 2016. Women who underwent the Kristeller maneuver were recruited as cases. For each case, a control (no Kristeller) was recruited matched for body mass index, use of epidural analgesia, duration of second stage of labor and birth weight. All women were invited to undergo four-dimensional (4D) transperineal ultrasound (TPU) 3-6 months postpartum. The main outcome measure was the presence of LAM avulsion on 4D-TPU. TPU results were compared between cases and controls. Multivariate logistic regression analysis was performed to identify independent risk factors for LAM avulsion.

RESULTS

During the study period, 134 women in the Kristeller maneuver group and 128 women in the control group underwent TPU assessment. Women who underwent the Kristeller maneuver had a higher prevalence of LAM avulsion than did controls (38/134 (28.4%) vs 18/128 (14.1%); P = 0.005). In addition, women in the Kristeller-maneuver group had a larger hiatal area on maximum Valsalva maneuver and a greater increase in hiatal area from rest to maximum Valsalva. On multivariate logistic regression analysis, use of the Kristeller maneuver was the only independent factor associated with LAM avulsion (odds ratio, 2.5 (95% CI, 1.29-4.51)).

CONCLUSION

The Kristeller maneuver is associated with an increased risk of LAM avulsion when applied in women during their first vaginal delivery. This should be taken into account when deciding to use fundal pressure to accelerate the second stage of labor and when counseling women following childbirth. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Recommended standardized terminology of the anterior female pelvis based on a structured medical literature review

BACKGROUND

The use of imprecise and inaccurate terms leads to confusion amongst anatomists and medical professionals.

OBJECTIVE

We sought to create recommended standardized terminology to describe anatomic structures of the anterior female pelvis based on a structured review of published literature and selected text books.

STUDY DESIGN

We searched MEDLINE from its inception until May 2, 2016, using 11 medical subject heading terms to identify studies reporting on anterior female pelvic anatomy; any study type published in English was accepted. Nine textbooks were also included. We screened 12,264 abstracts, identifying 200 eligible studies along with 13 textbook chapters from which we extracted all pertinent anatomic terms.

RESULTS

In all, 67 unique structures in the anterior female pelvis were identified. A total of 59 of these have been previously recognized with accepted terms in Terminologia Anatomica, the international standard on anatomical terminology. We also identified and propose the adoption of 4 anatomic regional terms (lateral vaginal wall, pelvic sidewall, pelvic bones, and anterior compartment), and 2 structural terms not included in Terminologia Anatomica (vaginal sulcus and levator hiatus). In addition, we identified 2 controversial terms (pubourethral ligament and Grafenberg spot) that require additional research and consensus from the greater medical and scientific community prior to adoption or rejection of these terms.

CONCLUSION

We propose standardized terminology that should be used when discussing anatomic structures in the anterior female pelvis to help improve communication among researchers, clinicians, and surgeons.

Maternal birth trauma: why should it matter to urogynaecologists?

PURPOSE OF REVIEW

There is increasing awareness of the importance of intrapartum events for future pelvic floor morbidity in women. In this review, we summarize recent evidence and potential consequences for clinical practice.

RECENT FINDINGS

Both epidemiological evidence and data from perinatal imaging studies have greatly improved our understanding of the link between childbirth and later morbidity. The main consequences of traumatic childbirth are pelvic organ prolapse (POP) and anal incontinence. In both instances the primary etiological pathways have been identified: levator trauma in the case of POP and anal sphincter tears in the case of anal incontinence. As most such trauma is occult, imaging is required for diagnosis.

SUMMARY

Childbirth-related major maternal trauma is much more common than generally assumed, and it is the primary etiological factor in POP and anal incontinence. Both sphincter and levator trauma can now be identified on imaging. This is crucial not only for clinical care and audit, but also for research. Postnatally diagnosed trauma can serve as intermediate outcome measure in intervention trials, opening up multiple opportunities for clinical research aimed at primary and secondary prevention.

New Measures for Predicting Birth-Related Pelvic Floor Trauma

OBJECTIVES

The aim of this study was to establish the predictive role of obstetric variables for obstetric outcomes and birth related levator ani muscle (LAM) trauma.

METHODS

In this prospective study, women underwent 3-dimensional pelvic floor ultrasound at their first appointment at 36 weeks and also 3 months postpartum. The measurements included minimal levator hiatus circumference (MLHC) and the ratio of fetal head circumference to MLHC = head-induced stretch ratio (HISR) as an indicator of the discrepancy between passage and passing canal. To derive the true impact of baby's mass on the levator ani musculature, we devised the levator ani stretch ratio (LASR), which was calculated by multiplying the HISR and the baby's weight.

RESULTS

Data set of 173 women was available for analysis. Mean HISR and LASR values were statistically different across all binary outcome categories, with 1 exception for HISR and levator ani injury. The odds ratios for LASR indicated positive and statistically significant associations with all obstetric outcomes examined. The probability of the LASR correctly classifying those with the adverse obstetric outcome, as estimated by the area under the curve, ranged from 0.64 to 0.80 with the strongest discriminatory ability observed for severe LAM trauma.

CONCLUSIONS

Fetal head circumference/mother MLHC ratio (HISR) is associated with longer length of second stage of labor, assisted delivery, and increased severity of perineal trauma. Similar associations were observed for LASR, but in addition, LASR had good discriminatory ability to identify severe LAM trauma.

Forceps delivery is associated with increased risk of pelvic organ prolapse and muscle trauma: a cross-sectional study 16-24 years after first delivery

OBJECTIVES

To study possible associations between mode of delivery and pelvic organ prolapse (POP) and pelvic floor muscle trauma 16-24 years after first delivery and, in particular, to identify differences between forceps and vacuum delivery.

METHODS

This was a cross-sectional study including 608 women who delivered their first child in 1990-1997 and were examined with POP quantification (POP-Q) and pelvic floor ultrasound in 2013-2014. Outcome measures were POP ≥ Stage 2 or previous prolapse surgery, levator avulsion and levator hiatal area on Valsalva. Univariable and multivariable logistic regression analyses and ANCOVA were applied to identify outcome variables associated with mode of delivery.

RESULTS

Comparing forceps to vacuum delivery, the adjusted odds ratios (aOR) were 1.72 (95% CI, 1.06-2.79; P = 0.03) for POP ≥ Stage 2 or previous prolapse surgery and 4.16 (95% CI, 2.28-7.59; P < 0.01) for levator avulsion. Hiatal area on Valsalva was larger, with adjusted mean difference (aMD) of 4.75 cm(2) (95% CI, 2.46-7.03; P < 0.01). Comparing forceps with normal vaginal delivery, the adjusted odds ratio (aOR) was 1.74 (95% CI, 1.12-2.68; P = 0.01) for POP ≥ Stage 2 or surgery and 4.35 (95% CI, 2.56-7.40; P < 0.01) for levator avulsion; hiatal area on Valsalva was larger, with an aMD of 3.84 cm(2) (95% CI, 1.78-5.90; P < 0.01). Comparing Cesarean delivery with normal vaginal delivery, aOR was 0.06 (95% CI, 0.02-0.14; P < 0.01) for POP ≥ Stage 2 or surgery and crude OR was 0.00 (95% CI, 0.00-0.30; P < 0.01) for levator avulsion; hiatal area on Valsalva was smaller, with an aMD of -8.35 cm(2) (95% CI, -10.87 to -5.84; P < 0.01). No differences were found between vacuum and normal vaginal delivery.

CONCLUSIONS

We found that mode of delivery was associated with POP and pelvic floor muscle trauma in women from a general population, 16-24 years after their first delivery. Forceps was associated with significantly more POP, levator avulsion and larger hiatal areas than were vacuum and normal vaginal deliveries. There were no statistically significant differences between vacuum and normal vaginal deliveries. Cesarean delivery was associated with significantly less POP and pelvic floor muscle trauma than were normal or operative vaginal delivery.

Pregnancy-induced adaptations in the intrinsic structure of rat pelvic floor muscles

OBJECTIVE

Maternal birth trauma to the pelvic floor muscles (PFMs) is a major risk factor for pelvic floor disorders. Modeling and imaging studies suggest that demands placed on PFMs during childbirth exceed their physiologic limits; however many parous women do not sustain PFM injury. Here we determine whether pregnancy induces adaptations in PFM architecture, the strongest predictor of muscle function, and/or intramuscular extracellular matrix (ECM), responsible for load bearing. To establish if parallel changes occur in muscles outside of the PFM, we also examined a hind limb muscle.

STUDY DESIGN

Coccygeus, iliocaudalis, pubocaudalis, and tibialis anterior of 3-month-old Sprague-Dawley virgin, mid-pregnant, and late-pregnant; 6-month-old virgin; and 4- and 12-week postpartum rats (N = 10/group) were fixed in situ and harvested. Major architectural parameters determining muscle's excursion and force-generating capacity were quantified, namely, normalized fiber length (Lfn), physiologic cross-sectional area, and sarcomere length. Hydroxyproline content was used as a surrogate for intramuscular ECM quantity. Analyses were performed by 2-way analysis of variance with Tukey post hoc testing at a significance level of .05.

RESULTS

Pregnancy induced a significant increase in Lfn in all PFMs by the end of gestation relative to virgin controls. Fibers were elongated by 37% in coccygeus (P < .0001), and by 21% in iliocaudalis and pubocaudalis (P < .0001). Importantly, no Lfn change was observed in the tibialis anterior. Physiologic cross-sectional area and sarcomere length were not affected by pregnancy. By 12 weeks' postpartum, Lfn of all PFMs returned to the prepregnancy values. Relative to virgin controls, ECM increased by 140% in coccygeus, 52% in iliocaudalis, and 75% in pubocaudalis in late-pregnant group, but remained unchanged across time in the tibialis anterior. Postpartum, ECM collagen content returned to prepregnancy levels in iliocaudalis and pubocaudalis, but continued to be significantly elevated in coccygeus (P < .0001).

CONCLUSION

This study demonstrates that pregnancy induces unique adaptations in the structure of the PFMs, which adjust their architectural design by adding sarcomeres in series to increase fiber length as well as mounting a substantial synthesis of collagen in intramuscular ECM.

Forceps: towards obsolescence or revival?

Cesarean section rates have become a political issue, attracting the attention of governments, health bureaucrats and professional organizations. In some instances this has led to a renewed interest in forceps delivery, even Kielland's rotational forceps. It is suggested that calls for a greater use of forceps, especially rotational forceps, are ill-advised and commonly based on ignorance of recent urogynecological and imaging literature. Forceps use is associated with a much higher likelihood of major maternal trauma, especially to the anal sphincter and levator ani muscles, which may result in substantial future morbidity. Hence, its use should be avoided whenever possible. This is particularly obvious for rotational forceps.

Prolonged second stage of labor and levator ani muscle injuries

Objective:

To determine the effect of pregnancy and vaginal delivery on the pelvic floor and levatorani morphology and function.

Methods:

Design. Cross-sectional study. Setting. Tertiary care teaching hospital. Population. 75 primigravid women were recruited for assessment at 6 weeks postpartum compared with 25 nulliparous women. Hiatal morphology and levator ani muscle avulsion were assessed by 4-dimensional translabial ultrasound examination. The volume achievement obtained by ultrasound was performed in supine position with empty bladder at rest, on maximum Valsalva maneuver, and on maximum pelvic floor muscle contraction. Main Outcome Measures. Hiatal diameter and area were measured at the plane of minimal hiatal dimension as defined in the midsagittal plane and Levator avulsion was assessed.

Results:

There were significant differences in hiatal area morphology at rest, on Valsalva maneuver and during contraction of muscles among the study groups, but there was no difference in pelvic diameter at rest, on Valsalva maneuver, and during contraction. There were 21 cases of puborectalis avulsion (42%) with no significant difference between non-progressive labor (8 cases) and Normal Vaginal Delivery (NVD) (13 cases) groups.

Conclusions:

The results of the present study showed that non-progressive labor is the main risk factor for pelvic muscle injuries, indicating the necessity of a better management and timely cesareans in women with prolonged second stage of labor.

How common is pelvic floor muscle atrophy after vaginal childbirth?

OBJECTIVE

To determine if there is evidence of levator ani atrophy in primiparous women.

METHODS

This was a prospective observational cohort study of 202 primiparous women recruited between November 2006 and March 2008. Translabial ultrasound volumes were obtained at 36-38 weeks' gestation and at a mean of 4.5 months postpartum. Peripartum changes in bladder neck elevation and reduction of anteroposterior hiatal diameter on pelvic floor muscle contraction (PFMC) and changes in muscle thickness were analyzed.

RESULTS

Of the 202 participants enrolled, 158 (78%) completed the study. There was a significant reduction in bladder neck elevation (P = 0.001) and change in anteroposterior hiatal diameter (P = 0.03) on PFMC when comparing antenatal and postnatal results, the latter being significantly associated with delivery mode (P = 0.013). No significant changes were detected in muscle thickness (P = 0.76).

CONCLUSIONS

There is a reduction in sonographic measures of pelvic floor function after childbirth, but muscle atrophy is unlikely to be a significant factor.

Pelvic floor trauma in childbirth

The investigation of female pelvic floor function and anatomy is moving from the fringes to the mainstream of urogynaecology and female urology, and it is becoming increasingly relevant for obstetrics. We are coming to realise that pelvic floor trauma in labour is common, usually overlooked, and a major factor in the causation of pelvic organ prolapse. Modern imaging methods such as magnetic resonance and 3D/4D ultrasound have enabled us to diagnose such trauma reliably and accurately, most commonly in the form of an avulsion of the puborectalis muscle; that is, a disconnection of the muscle from its insertion on the os pubis. Such damage to the levator muscle is macroscopically evident and can also be palpated, a skill that is available to every clinician, requiring neither investment nor specialised equipment. In this review, I will describe pelvic floor assessment by palpation and ultrasound and illustrate the commonest abnormalities and their clinical consequences. This paper will not focus on magnetic resonance imaging due to technical restrictions, cost and access issues in most jurisdictions, and because several papers have recently shown that ultrasound is at least as effective in diagnosing such trauma. Anal sphincter trauma is generally well covered in the literature and hence not subject of this review.

Diagnosis of levator avulsion injury: a comparison of three methods

OBJECTIVE

Levator avulsion is common after vaginal delivery and is strongly associated with prolapse and prolapse recurrence. The aim of this study was to compare assessment by digital palpation and two ultrasound methods, one using rendered volumes and the other multislice imaging, for the diagnosis of levator avulsion.

METHODS

We retrospectively analyzed randomly identified datasets of 266 women seen at a tertiary urogynecology unit. Each patient had undergone an interview, vaginal examination and 3D/4D translabial ultrasound examination. Analysis of the retrieved ultrasound volumes was performed offline, with the operator blinded to all clinical data, using two techniques: assessment of rendered volumes and evaluation on multislice imaging. We tested agreement between the three methods and the association of each method's results with symptoms and signs of pelvic organ prolapse.

RESULTS

Agreement between the findings on palpation and the two ultrasound methods with regard to diagnosis of levator avulsion ranged from 80% to 87% (Cohen's kappa, 0.35-0.56). The findings for all methods were significantly associated with symptoms, signs and ultrasound findings of pelvic organ prolapse (P=0.007 to < 0.001), with no single method appearing superior to the others.

CONCLUSIONS

Depending on the availability of local expertise and equipment, any of the three methods tested in this study may be used to document avulsion of the puborectalis muscle.

Can we identify the limits of the puborectalis/pubovisceralis muscle on tomographic translabial ultrasound?

OBJECTIVE

In order to determine the relative locations of puborectalis/pubovisceralis (PR/PV) and iliococcygeus (IC) muscles, we undertook an analysis of four-dimensional (4D) ultrasound datasets obtained after suburethral sling placement.

METHODS

This was a retrospective analysis of ultrasound volume data obtained in 110 women after undergoing the Monarc suburethral sling procedure. Tomographic ultrasound imaging (TUI) was performed with eight slices in the axial plane, from 5 mm below to 12.5 mm above the plane of minimal hiatal dimensions. Hyperechogenic tape material was rated as absent, present or as producing an anechoic acoustic shadow overlying the muscle in each slice.

RESULTS

Slices 7 and 8 virtually always showed evidence of the implant or its acoustic shadow on the pelvic sidewall (98% for slice 8 and 96% for slice 7), suggesting that these slices are located at the level of the obturator foramen. This implies that these slices do not generally contain PR/PV muscle, but rather IC muscle.

CONCLUSION

On standardized tomographic imaging of the levator hiatus and muscle, slices located ≥ 1 cm over the plane of minimal dimensions are very likely to contain IC muscle rather than PR/PV muscle.

Ultrasound in the investigation of posterior compartment vaginal prolapse and obstructed defecation

Recent developments in diagnostic imaging have made gynecologists, colorectal surgeons and gastroenterologists realize as never before that they share a common interest in anorectal and pelvic floor dysfunction. While we often may be using different words to describe the same phenomenon (e.g. anismus/vaginismus) or attributing different meanings to the same words (e.g. rectocele), we look after patients with problems that transcend the borders of our respective specialties. Like no other diagnostic modality, imaging helps us understand each other and provides new insights into conditions we all need to learn to investigate better in order to improve clinical management. In this review we attempt to show what modern ultrasound imaging can contribute to the diagnostic work-up of patients with posterior vaginal wall prolapse, obstructed defecation and rectal intussusception/prolapse. In summary, it is evident that translabial/perineal ultrasound can serve as a first-line diagnostic tool in women with such complaints, replacing defecation proctography and MR proctography in a large proportion of female patients. This is advantageous for the women themselves because ultrasound is much better tolerated, as well as for healthcare systems since sonographic imaging is much less expensive. However, there is a substantial need for education, which currently remains unmet.

Four-dimensional sonographic evaluation of avulsion of the levator ani according to delivery mode

OBJECTIVE

To determine the frequency of avulsion of the levator ani muscle in primiparous women according to delivery mode, using introital four-dimensional ultrasonography.

METHODS

We performed a prospective observational study at a tertiary obstetric unit. One hundred and eighty primiparous women were included and divided into three groups: normal vaginal delivery without episiotomy, forceps delivery and Cesarean section groups. Between 40 and 120 days after delivery, four-dimensional ultrasonography was performed in order to evaluate the integrity of the levator ani muscle. The operator was blinded to all clinical data and was not aware of delivery mode. The influence of other variables associated with delivery such as birth weight, body mass index, maternal age and use of epidural anesthesia was also studied.

RESULTS

Avulsion of the puborectalis component of the levator ani muscle was detected on ultrasonography in 61.7% of women who had undergone a forceps delivery, compared with 13.3% of those who had had a normal vaginal delivery and 0% of those who had had a Cesarean section. Bilateral avulsion was observed in 12/60 (20.0%) of the forceps group and in 2/60 (3.3%) of the normal vaginal delivery group (P < 0.001). Other variables did not seem to influence prevalence.

CONCLUSIONS

Forceps delivery is associated with an increased rate of avulsion of the puborectalis component of the levator ani muscle. The effect of forceps use is independent of other delivery-related variables.