The impact of levator ani muscle trauma and contraction on recurrence after prolapse surgery

Introduction and hypothesis

The objective was to explore the impact of levator ani muscle (LAM) trauma and pelvic floor contraction on symptoms and anatomy after pelvic organ prolapse (POP) surgery.

Methods

Prospective study including 200 women with symptomatic POP ≥ grade 2 examined 3 months prior to and 6 months after surgery. Prolapse in each compartment was graded using the Pelvic Organ Prolapse Quantification (POP-Q) system, and women answered yes/no to a question about bulge sensation. Pelvic floor muscle contraction was assessed with transperineal ultrasound measuring proportional change in levator hiatal anteroposterior diameter from rest to contraction. LAM trauma was diagnosed using tomographic ultrasound imaging. Statistical analysis was performed using multivariate logistic regression analysis.

Results

A total of 183 women (92%) completed the study. Anatomical recurrence (POP ≥ grade 2) was found in 76 women (42%), and a bulge sensation was reported by 35 (19%). Ninety-two women (50%) had LAM trauma, and this was associated with increased risk of anatomical recurrence (OR 2.1 (95% CI 1.1–4.1), p = 0.022), but not bulge sensation (OR 1.1 (95% CI 0.5–2.4), p = 0.809). We found a reduced risk of bulge sensation for women with absent to weak contraction compared with normal to strong contraction (OR 0.4 (95% CI 0.1–0.9), p = 0.031), but no difference in risk for POP ≥ 2 after surgery (OR 1.5 (95% CI 0.8–2.9), p = 0.223).

Conclusions

Levator ani muscle trauma was associated with increased risk of anatomical failure 6 months after POP surgery. Absent to weak pelvic floor muscle contraction was associated with reduced risk of bulge sensation after surgery.

Effect of preoperative pelvic floor muscle training on pelvic floor muscle contraction and symptomatic and anatomical pelvic organ prolapse after surgery: randomized controlled trial

OBJECTIVES

To evaluate the effect of preoperative pelvic floor muscle training (PFMT) on pelvic floor muscle (PFM) contraction, symptoms of pelvic organ prolapse (POP) and anatomical POP, 6 months after prolapse surgery, and to assess the overall changes in PFM contraction, POP symptoms and pelvic organ descent after surgery.

METHODS

This was a randomized controlled trial of 159 women with symptomatic POP, Stage 2 or higher, scheduled for surgery. Participants were randomized to intervention including daily PFMT from inclusion to surgery (n = 81) or no intervention (controls; n = 78). Participants were examined at inclusion, on the day of surgery and 6 months after surgery. PFM contraction was assessed by: vaginal palpation using the Modified Oxford scale (MOS; 0-5); transperineal ultrasound, measuring the percentage change in levator hiatal anteroposterior diameter (APD) from rest to maximum PFM contraction; vaginal manometry; and surface electromyography (EMG). POP distance from the hymen in the compartment with the most dominant prolapse and organ descent in the anterior, central and posterior compartments were measured on maximum Valsalva maneuver. POP symptoms were assessed based on the sensation of vaginal bulge, which was graded using a visual analog scale (VAS; 0-100 mm). Linear mixed models were used to assess the effect of PFMT on outcome variables.

RESULTS

Of the 159 women randomized, 151 completed the study, comprising 75 in the intervention and 76 in the control group. Mean waiting time for surgery was 22 ± 9.7 weeks and follow-up was performed on average 28 ± 7.8 weeks after surgery. Postoperatively, no difference was found between the intervention and control groups with respect to PFM contraction assessed by vaginal palpation (MOS, 2.4 vs 2.2; P = 0.101), manometry (19.4 vs 19.7 cmH₂ O; P = 0.793), surface EMG (33.5 vs 33.1 mV; P = 0.815) and ultrasound (change in hiatal APD, 20.9% vs 19.3%; P = 0.211). Furthermore, no difference between groups was found for sensation of vaginal bulge (VAS, 7.4 vs 6.0 mm; P = 0.598), POP distance from the hymen in the dominant prolapse compartment (-1.8 vs -2.0 cm; P = 0.556) and sonographic descent of the bladder (0.5 vs 0.8 cm; P = 0.058), cervix (-1.3 vs -1.1 cm; P = 0.569) and rectal ampulla (0.3 vs 0.4 cm; P = 0.434). In all patients, compared with findings at initial examination, muscle contraction improved after surgery, as assessed by palpation (MOS, 2.1 vs 2.3; P = 0.007) and ultrasound (change in hiatal APD, 17.5% vs 20.1%; P = 0.001), and sensation of vaginal bulge was reduced (VAS, 57.6 vs 6.7 mm; P < 0.001). In addition, compared with the baseline examination, POP distance from the hymen in the dominant prolapse compartment (1.9 vs -1.9 cm; P < 0.001) and sonographic descent of the bladder (1.3 vs 0.6 cm; P < 0.001), cervix (0.0 vs -1.2 cm; P < 0.001) and rectal ampulla (0.9 vs 0.4 cm; P = 0.001) were reduced.

CONCLUSIONS

We found no effect of preoperative PFMT on PFM contraction, POP symptoms or anatomical prolapse after surgery. In all patients, PFM contraction and POP symptoms were improved at the 6-month follow-up, most likely due to the anatomical correction of POP. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Ultrasound assessment of pelvic floor muscle contraction: reliability and development of an ultrasound-based contraction scale

OBJECTIVES

To determine intra- and interrater reliability and agreement for ultrasound measurements of pelvic floor muscle contraction and to assess the correlation between ultrasound and vaginal palpation. We also aimed to develop an ultrasound scale for assessment of pelvic floor muscle contraction.

METHODS

This was a cross-sectional study of 195 women scheduled for stress urinary incontinence (n = 65) or prolapse (n = 65) surgery or who were primigravid (n = 65). Pelvic floor muscle contraction was assessed by vaginal palpation using the Modified Oxford Scale (MOS) and by two- and three-dimensional (2D/3D) transperineal ultrasound. Proportional change in 2D and 3D levator hiatal anteroposterior (AP) diameter and 3D levator hiatal area between rest and contraction were used as measures of pelvic floor muscle contraction. One rater repeated all ultrasound measurements on stored volumes, which were used for intrarater reliability and agreement analysis, and three independent raters analyzed 60 ultrasound volumes for interrater reliability and agreement analysis. Reliability was assessed using the intraclass correlation coefficient (ICC) and agreement using Bland-Altman analysis. Tomographic ultrasound was used to identify women with major levator injury. Spearman's rank correlation coefficient (r_S ) was used to assess the correlation between ultrasound measurements of pelvic floor muscle contraction and MOS score. The proportion of women allocated to each category of muscle contraction (absent, weak, moderate or strong) by palpation was used to determine the cut-offs for the ultrasound scale.

RESULTS

Intrarater ICC was 0.81 (95% CI, 0.74-0.85) for proportional change in 2D levator hiatal AP diameter. Interrater ICC was 0.82 (95% CI, 0.72-0.89) for proportional change in 2D AP diameter, 0.80 (95% CI, 0.69-0.88) for proportional change in 3D AP diameter and 0.72 (95% CI, 0.56-0.83) for proportional change in hiatal area. The prevalence of major levator injury was 22.6%. The strength of correlation (r_S ) between ultrasound measurements and MOS score was 0.52 for 2D AP diameter, 0.62 for 3D AP diameter and 0.47 for hiatal area (P < 0.001 for all). On the ultrasound contraction scale, proportional change in 2D levator hiatal AP diameter of < 1% corresponds to absent, 2-14% to weak, 15-29% to normal and > 30% to strong contraction.

CONCLUSIONS

Ultrasound seems to be an objective and reliable method for evaluation of pelvic floor muscle contraction. Proportional change in 2D levator hiatal AP diameter had the highest ICC and moderate correlation with MOS score assessed by vaginal palpation, and we constructed an ultrasound scale for assessment of pelvic floor muscle contraction based on this measure. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Association between pelvic floor muscle trauma and contraction in parous women from a general population

OBJECTIVE

To study possible associations between pelvic floor muscle contraction, levator ani muscle (LAM) trauma and/or pelvic organ prolapse (POP) ≥ Stage 2 in parous women recruited from a general population.

METHODS

This was a secondary analysis of data from a cross-sectional study of 608 parous women from a general population examined using the POP quantification system (POP-Q) and three-dimensional/four-dimensional transperineal ultrasound for identification of LAM macrotrauma (avulsion) and microtrauma (distension of levator hiatal area > 75^th percentile on Valsalva maneuver). Muscle contraction was assessed using the modified Oxford scale (MOS), perineometry and ultrasound measurement of proportional change of anteroposterior hiatal diameter and levator hiatal area at rest and on pelvic floor muscle contraction. The Mann-Whitney U-test was used to study associations between pelvic floor muscle contraction, LAM trauma and POP.

RESULTS

Women with macrotrauma (n = 113) had significantly weaker median pelvic floor muscle contraction, as measured using MOS and perineometry, than did women with an intact LAM (n = 493) (contraction strength was 1.5 (range, 0.0-5.0) vs 3.5 (range, 0.0-5.0) on MOS, and vaginal squeeze pressure was 15.0 (range, 0.0-78.0) cmH₂ O vs 28.0 (range, 0.0-129.0) cmH₂ O on perineometry; P < 0.001). This was also demonstrated by ultrasound measurement, with a proportional change in hiatal area of 19.9% (range, 4.1-48.0%) vs 34.0% (range, 0.0-64.0%) (P < 0.001) and proportional change in anteroposterior diameter of 16.2% (range, -5.7 to 42.6%) vs 26.0% (range, -3.4 to 49.4%) (P < 0.001). No statistically significant difference between women with (n = 65), and those without (n = 378), microtrauma was found after excluding women with macrotrauma. Women with POP had weaker muscle contraction than those without; in those with POP-Q ≥ 2 (n = 275) compared with those with POP-Q < 2 (n = 333), muscle contraction strength was 3.0 (range, 0.0-5.0) vs 3.5 (range, 0.0-5.0) on MOS, vaginal squeeze pressure was 21.0 (range, 0.0-98.0) cmH₂ O vs 28.0 (range, 3.0-129.0) cmH₂ O on perineometry, proportional change in hiatal area was 29.6% (range, 0.0-60.9%) vs 33.8% (range, 0.0-64.4%) and proportional change in anteroposterior diameter was 22.8% (range, -5.7 to 49.4%) vs 25.7% (range, -3.4 to 49.4%) (P < 0.001 for all).

CONCLUSIONS

LAM macrotrauma was associated with weaker pelvic floor muscle contraction measured using palpation, perineometry and ultrasound. Women with POP had weaker contraction than did women without POP. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.