Natural history of levator ani muscle avulsion 4 years following childbirth

OBJECTIVES

The primary aim was to evaluate prospectively the natural history of levator ani muscle (LAM) avulsion 4 years following first delivery and its correlation with signs and symptoms of pelvic floor dysfunction (PFD). The secondary aim was to investigate the effect of a second vaginal delivery on the incidence of LAM avulsion and PFD.

METHODS

This was a prospective longitudinal study of nulliparous women recruited antenatally, who were assessed at 36 weeks' gestation and 3 months, 1 year and 4 years postpartum for signs and symptoms of PFD and presence of LAM avulsion. Pelvic floor muscle strength was assessed by digital palpation, and pelvic organ prolapse (POP) was assessed using the POP quantification (POP-Q) system. Validated questionnaires were used to evaluate urinary, bowel and sexual function and symptoms of POP. Transperineal ultrasound was performed to assess LAM integrity and hiatal biometry. Differences in signs and symptoms of PFD over time were evaluated using a linear mixed model, separately in women who had had one delivery and in those who had two or more deliveries during the study period.

RESULTS

Of 269 women recruited, 147 (55%) attended the 4-year follow-up and were examined at a mean interval of 3.8 ± 0.4 years after their first delivery. Of these, 74 (50%) had a subsequent delivery. The prevalence of LAM avulsion 4 years after a first vaginal delivery was 13%, with no difference between women who had one and those who had two or more vaginal deliveries. Women with an intact LAM and one or more deliveries showed no change in signs and symptoms of PFD at 4 years compared with the previous assessments. Of women with one vaginal delivery who were diagnosed with LAM avulsion 3 months or 1 year postpartum, those in whom the LAM avulsion was no longer evident at 4 years (42%) showed worsening of POP-Q measurements, whereas those with persistent LAM avulsion (58%) showed significant worsening in pelvic floor muscle strength and hiatal area on ultrasound. After a second vaginal delivery, no new avulsions were diagnosed, however, previous LAM avulsion became more extensive in 44% of women and hiatal area increased in women with persistent LAM avulsion.

CONCLUSIONS

The first vaginal delivery carries the greatest risk for LAM avulsion, with impact on signs of PFD 4 years later. A second vaginal delivery could result in deterioration of LAM avulsion, but no new avulsions were found. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Women with advanced pelvic organ prolapse and levator ani muscle avulsion would significantly benefit from mesh repair surgery

OBJECTIVES

Mesh repair surgery for pelvic organ prolapse (POP) has been suspended in some countries owing to concerns about its associated complications. However, mesh repair has been shown to reduce the risk of prolapse recurrence after surgery. In view of this controversy, our aim was to assess the incidence of subjective and objective recurrence of POP following mesh repair surgery vs native-tissue repair in women with Stage-III or Stage-IV POP.

METHODS

This was a prospective observational study of women who presented with Stage-III or Stage-IV POP and received primary prolapse surgery between 2013 and 2018. Transperineal ultrasound was performed before the operation and volumes were analyzed offline to assess the presence of levator ani muscle (LAM) avulsion. All women were counseled on either mesh repair or native-tissue reconstruction. The mesh-repair group was followed up for up to 5 years and the native-tissue-repair group for up to 2 years after the operation. Prolapse symptoms and POP quantification (POP-Q) staging were assessed at follow-up. Subjective recurrence of POP was defined as symptoms of prolapse (vaginal bulge sensation or dragging sensation) reported by the patient. Objective recurrence was defined as POP-Q ≥ Stage II. The subjective and objective recurrences of prolapse were compared between women with and those without mesh use. Multivariate regression analysis was used to identify risk factors for the recurrence of POP.

RESULTS

A total of 154 Chinese women with Stage-III or Stage-IV prolapse were recruited. Of these, 104 (67.5%) underwent mesh repair (transabdominal in 57 women and transvaginal in 47 women) and 50 (32.5%) had native-tissue repair surgery. Ninety-five (61.7%) women had LAM avulsion. Both the subjective POP recurrence rate (4.8% vs 20.0%; P = 0.003) and the objective recurrence rate (20.2% vs 46.0%; P = 0.001) were significantly lower in the mesh-repair group than in the native-tissue-repair group. On multivariate logistic regression analysis, mesh repair was associated significantly with a reduced risk of subjective recurrence (odds ratio (OR), 0.20 (95% CI, 0.07-0.63)) and of objective recurrence (OR, 0.16 (95% CI, 0.07-0.55)) of prolapse. On subgroup analysis of women with LAM avulsion, mesh repair significantly reduced the risk of subjective recurrence (OR, 0.24 (95% CI, 0.07-0.87)) and objective recurrence (OR, 0.23 (95% CI, 0.09-0.57)) of POP. The incidence of mesh-related complications was low, and mesh exposure could be treated conservatively or by minor surgery.

CONCLUSIONS

Mesh repair surgery, compared with native-tissue repair, was associated with a 5-fold reduction in the risk of subjective recurrence and a 6-fold reduction in the risk of objective recurrence of prolapse in women with Stage-III or Stage-IV POP. In women with concomitant LAM avulsion, mesh repair surgery was associated with a 4-fold reduction in both objective and subjective recurrence of POP. The rate of mesh-related complications was low, and mesh exposure could be treated conservatively or by minor surgery. The benefit of mesh surgery for these high-risk women appears to outweigh the risks of mesh complications, and it could be a treatment option for this group of women. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Change in prevalence of major levator ani muscle defects from 6 weeks to 1 year postpartum, and maternal and obstetric risk factors: A longitudinal ultrasound study

INTRODUCTION

The present study aimed first to investigate the change in prevalence of major levator ani muscle (LAM) defects, also called avulsions, from 6 weeks to 1 year postpartum, and second to assess maternal and obstetric risk factors for having persistent major LAM defects/avulsions at 1 year postpartum.

MATERIAL AND METHODS

This is a secondary analysis of data from a prospective cohort study including 300 nulliparous women at 17-19 weeks of gestation. Major LAM defects were diagnosed at 6 weeks and 1 year postpartum using transperineal ultrasonography. We defined persistent major LAM defects as a defect diagnosed both at 6 weeks and 1 year postpartum. Maternal and obstetric data were obtained from the hospital's electronic birth records. Pelvic floor muscle function was measured vaginally by manometer at 21 weeks of gestation. The main outcome measurement was change in prevalence of major LAM defects. Maternal and obstetric risk factors for having persistent major LAM defect were also assessed.

RESULTS

Prevalence of major LAM defects was 19.4% at 6 weeks and 10.4% at 1 year postpartum. No new major LAM defects were diagnosed at 1 year postpartum. Persisting major LAM defects were associated with longer second stage of labor (median 74.5 minutes vs median 48.0 minutes, P = .012) and higher neonatal birthweight (mean difference of 232.3 g, 95% confidence interval [CI] 21.5-443.1). Vacuum delivery was independently associated with persistent major LAM defects, adjusted OR 3.0 (95% CI 1.0-9.0).

CONCLUSIONS

There was a 50% reduction of sonographically diagnosed major LAM defects from 6 weeks to 1 year postpartum. This finding suggests that assessment of the major LAM 6 weeks postpartum may be too early to diagnose defects/avulsions. Long second stage of labor, high neonatal birthweight and vacuum delivery were associated with persistent major LAM defects/avulsions.

Influence of the disengagement of the forceps on levator ani muscle injuries in instrumental delivery: A multicenter study

INTRODUCTION

Forceps use is the main risk factor for levator ani muscle (LAM) injuries. We believe that the disengagement of the forceps branches before delivery of the fetal head could influence LAM injuries, so we aimed to determine the influence of the disengagement of the forceps on the occurrence of LAM avulsion during forceps delivery.

MATERIAL AND METHODS

A prospective, observational, multicenter study was conducted with 261 women who underwent forceps delivery. The women were classified according to whether the branches of the forceps had been disengaged before delivery of the fetal head. LAM avulsion was defined using a multislice mode (3 central slices).

RESULTS

In all, 255 women completed the study (160 without disengagement and 95 with disengagement). LAM avulsions were observed in 37.9% of women in the group with disengagement and in 41.9% of women in the group without disengagement. The crude OR (without disengagement vs with disengagement) for avulsion was 0.90 (95% CI 0.49-1.67, P = 0.757) and an adjusted OR of 0.82 (95% CI 0.40-1.69, P = 0.603).

CONCLUSIONS

We did not observe a statistically significant reduction in the LAM avulsion rate with disengagement of the forceps branches before delivery of the fetal head.

Pelvic organ prolapse as a function of levator ani avulsion, hiatus size, and strength

BACKGROUND

Obstetrical levator ani muscle avulsion is detected after 10%-30% of vaginal deliveries and is associated with pelvic organ prolapse later in life. However, the mechanism by which levator avulsion may contribute to prolapse is unknown.

OBJECTIVES

This study investigated the extent by which size of the levator hiatus and pelvic muscle weakness may explain the association between levator avulsion and pelvic organ prolapse.

STUDY DESIGN

This was a supplementary study of a longitudinal cohort of parous women enrolled 5-10 years after first delivery and assessed annually for prolapse (defined as descent beyond the hymen) for up to 9 annual visits. For this substudy, vaginally parous participants were assessed for levator avulsion using 3-dimensional transperineal ultrasound. Ultrasound was performed at a median interval of 11 years from delivery. Ultrasound volumes also were used to measure levator hiatus area with Valsalva. Pelvic muscle strength was measured with perineometry. Women with and without pelvic organ prolapse were compared for levator avulsion, levator hiatus area, and pelvic muscle strength, using multivariable logistic regression yielding a measure of mediation. Bootstrap methods were used to calculate the confidence interval corresponding to the measure of mediation by hiatus area and pelvic muscle strength.

RESULTS

Prolapse was identified in 109 of 429 (25%) and was significantly associated with levator avulsion (odds ratio, 4.17; 95% confidence interval, 2.28-7.31). Prolapse also was associated with levator hiatus area (odds ratio, 1.52 per 5 cm²; 95% confidence interval, 1.34-1.73) and inversely with muscle strength (odds ratio, 0.87 per 5 cm H₂O; 95% confidence interval, 0.81-0.94). In a multivariable logistic model including levator avulsion, levator hiatus area, and strength, the association between levator avulsion and prolapse was substantially attenuated and indeed was no longer statistically significant (odds ratio, 1.75; 95% confidence interval, 0.91-3.39). Hiatus area and strength mediated 61% (95% confidence interval, 34%-106%) of the association between avulsion and prolapse. Furthermore, since the 95% confidence interval for this estimate contained 100%, it cannot be ruled out that the 2 markers fully mediate the effect of avulsion on prolapse.

CONCLUSIONS

The strong association between pelvic organ prolapse and levator avulsion can be explained to a large extent by a larger levator hiatus and weaker pelvic muscles after levator avulsion.

Impact of levator muscle avulsions on Manchester procedure outcomes in pelvic organ prolapse surgery

INTRODUCTION

Levator ani muscle avulsions potentially increase recurrence after anterior colporrhaphies. We aimed at evaluating the impact of avulsions on anatomical and patient-reported outcomes 1 year after the Manchester procedure for primary anterior compartment pelvic organ prolapse.

MATERIAL AND METHODS

Prospective cohort study of 189 women undergoing the Manchester procedure between October 2014 and January 2017. Avulsions were diagnosed by transperineal ultrasound. Women with and without avulsions were compared for 1-year postoperative outcomes; Pelvic Organ Prolapse Quantification measurements, subjective satisfaction (1-worse to 4-cured), failure (new prolapse treatment), response to validated questionnaires on pelvic floor distress and sexual function, and a composite outcome (subjectively cured and optimal anterior compartment outcome (stage 0-I)). Optimal mid-compartment outcome was defined as cervix ≥5 cm above the hymen. Factors potentially associated with poor anatomical outcomes (anterior compartment stage ≥II) or pelvic floor distress were analyzed using regression analyses.

RESULTS

Fewer women with avulsions (present in 50.8%) obtained optimal mid-compartment outcomes (88.2% vs 77.1%; P = 0.05). The groups were otherwise similar in terms of mid-compartment reduction, anterior compartment results, failure rate, subjective satisfaction, pelvic floor/sexual symptoms, and combined optimal subjective and anatomical outcome. Only preoperative anterior compartment stage ≥III was associated with poor anatomical outcome (P < 0.01). A high preoperative symptom score was associated with a high postoperative symptom score (P < 0.001).

CONCLUSIONS

Although fewer women with avulsions obtained optimal mid-compartment results, avulsions had no impact on other anatomical or symptomatic outcomes 1 year after the Manchester procedure for primary anterior compartment prolapse.

Longitudinal pelvic floor biometry: which factors affect it?

OBJECTIVES

To evaluate pelvic floor biometry of women 3-5 years after their first delivery. The effect of a subsequent delivery and the mode of delivery on pelvic floor biometry were also studied.

METHODS

Three-hundred and twenty-eight women who had been examined by translabial ultrasound during their first singleton pregnancy and at 8 weeks and 1 year postpartum, were invited for a follow-up 3-5 years later. The positions of the bladder neck, cervix, anorectal junction and hiatal area (HA) were evaluated using translabial ultrasound. The effects of parity, mode of delivery and levator ani muscle avulsion were studied.

RESULTS

A total of 240 women completed the study. Of these, 179 had one or more vaginal deliveries (VD) (VD-only group), 52 had one or more Cesarean sections (CS) (CS-only group) and nine had both VD and CS at follow-up. The mean interval between the first delivery and follow-up was 3.8 years. A significantly lower bladder neck and anorectal junction on Valsalva, a lower cervix at rest, on Valsalva and pelvic floor muscle contraction, and a greater HA were observed in the VD-only group at follow-up, compared with findings at 1 year of follow-up or in the first pregnancy. The findings were similar in the CS-only group, except without a lower anorectal junction on Valsalva. Compared with the primiparous VD-only group, a greater HA at rest was observed in the multiparous VD-only group (P = 0.027). The VD-only group had a greater HA than the CS-only group.

CONCLUSIONS

At 3-5 years after first delivery, a lower bladder neck, cervix and anorectal junction, and a greater HA were observed compared with findings in the first trimester and at 1 year of follow-up, regardless of parity or mode of delivery. Women with two or more VDs had a greater HA compared with those who had only one VD, and women with at least one VD had a greater HA compared with those who delivered by CS only. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Longitudinal follow-up of levator ani muscle avulsion: does a second delivery affect it?

OBJECTIVES

To evaluate the morphological outcome of levator ani muscle (LAM) avulsion 3-5 years after a first delivery and to assess the effect of a second delivery on this condition. The impact of LAM avulsion on pelvic floor disorders was also studied.

METHODS

Six hundred and sixty-six women who had been assessed for LAM avulsion 8 weeks after their first delivery were invited for a follow-up examination 3-5 years later. Women completed the Pelvic Floor Distress Inventory including the Urinary Distress Inventory (UDI) and Pelvic Organ Prolapse Distress Inventory (POPDI) questionnaires to explore symptoms of pelvic floor disorders, and the pelvic floor was examined using three-dimensional translabial ultrasound and assessed using the pelvic organ prolapse quantification system.

RESULTS

Three hundred and ninety-nine women completed the study, of whom 151 were multiparous. Mean interval between first delivery and follow-up was 42.3 ± 7.6 months. Among 69 women who had LAM avulsion 8 weeks after their first delivery, nine (13.0%) had no LAM avulsion at follow-up. One (0.9%) woman had a new LAM avulsion after her second vaginal delivery. A greater proportion of women with LAM avulsion reported symptoms of stress urinary incontinence (SUI) (adjusted odds ratio, 2.09 (95% CI, 1.18-3.70); P = 0.01) and symptoms of prolapse than did women without avulsion; however, this difference did not reach statistical significance (P = 0.61). Women with LAM avulsion had higher UDI and POPDI scores than did women without avulsion (median UDI score, 17.7 (interquartile range (IQR), 5.0-32.4) vs 9.2 (IQR, 0.0-22.1); P = 0.045 and median POPDI score, 20.8 (IQR, 8.8-40.5) vs 10.7 (IQR, 0.0-32.8); P = 0.021).

CONCLUSIONS

The risk of developing new LAM avulsion after a second vaginal delivery is low (0.9%). Healing of LAM avulsion was observed in 13% of women who had at least one vaginal delivery. At 3-5 years after delivery, women with LAM avulsion reported symptoms of SUI more often than did those without, and had higher UDI and POPDI scores, implying more bothersome symptoms. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Is obstetric anal sphincter injury a risk factor for levator ani muscle avulsion in vaginal delivery?

OBJECTIVE

To analyze whether women who sustain obstetric anal sphincter injury (OASI) in their first vaginal delivery have a higher incidence of levator ani muscle (LAM) avulsion than do women without OASI.

METHODS

We conducted a prospective observational cohort study of 80 primiparous women who gave birth at our tertiary obstetric unit between September 2011 and July 2013. The women were divided into two groups: women diagnosed with OASI during vaginal delivery (n = 40) and women without OASI (n = 40), matched by mode of delivery and newborn birth weight. Four-dimensional (4D) transperineal ultrasound was performed in all participants at 6-12 months after delivery to assess for integrity or avulsion of the LAM. Ultrasound images were evaluated by two observers who were blinded to group assignment and clinical data. Interobserver agreement was assessed to determine the reproducibility of 4D transperineal ultrasound for diagnosing LAM avulsion.

RESULTS

We found no statistically significant differences between the two groups. The incidence of LAM avulsion was 24.3% in the OASI group and 34.2% in the control group (P = 0.448). Interobserver agreement in the diagnosis of LAM avulsion in the study population using 4D transperineal ultrasound was 89.5%, with a kappa index of 0.76.

CONCLUSIONS

Our findings do not support OASI as a risk factor for LAM avulsion. Prospective studies in larger populations are needed to establish the biomechanical relationships of the pelvic floor structures involved in vaginal delivery. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Inter-rater reliability of assessment of levator ani muscle strength and attachment to the pubic bone in nulliparous women

OBJECTIVES

The modified Oxford scale (MOS) has been found previously to have poor inter-rater reliability, whereas digital assessment of levator ani muscle (LAM) attachment to the pubic bone has been shown to have acceptable reliability. Our aim was to evaluate inter-rater reliability of the validated MOS and to develop a reliable classification system for digital assessment of LAM attachment, correlating this to findings on transperineal ultrasound (TPUS) examination.

METHODS

Evaluation of the MOS by palpation was performed in nulliparous women by two investigators. LAM attachment was evaluated using digital palpation, for which a novel classification system was developed with four grades based on the position of the attachment and presence of discernible muscle. Findings were compared with those on TPUS examination. Inter-rater reliability was assessed using Cohen's kappa statistic.

RESULTS

Twenty-five nulliparous women were examined. There was agreement in MOS scores between the investigators in 64% of women (n = 16), with a kappa of 0.66 (indicating substantial agreement). There was agreement in palpation of LAM attachment using the new grading system in 96% of women (n = 24), with a kappa of 0.90 (indicating almost perfect agreement). TPUS examination did not show LAM avulsion in any woman, with the exception of one with a partial avulsion.

CONCLUSION

In this group of nulliparous patients, there was substantial agreement between the two investigators in evaluation of the MOS and there was good agreement between grades of LAM attachment using the new classification system, which correlated with findings on TPUS examination. It therefore appears that these results are reproducible in nulliparous women and the techniques can be readily learned and reliably incorporated into clinical practice and research after appropriate training. Further research is required to establish clinical utility of the grading system for LAM attachment in postpartum women and in women with symptomatic pelvic organ prolapse.