Correlation between levator ani muscle injuries on magnetic resonance imaging and fecal incontinence, pelvic organ prolapse, and urinary incontinence in primiparous women

Abstract

Objective-To correlate the presence of major levator ani muscle (LAM) injuries on magnetic resonance imaging (MRI) with fecal incontinence (FI), pelvic organ prolapse (POP) and urinary incontinence (UI) in primiparous women 6-12 months postpartum.Study design-A published scoring system was used to characterize LAM injuries on MRI dichotomously (MRI−, no/mild versus MRI+, major).Results-Major LAM injuries were observed in 17/89(19.1%) women who delivered vaginally with external anal sphincter (EAS) injuries, in 3/88(3.5%) who delivered vaginally without EAS injury, and in 0/29(0%) who delivered by Cesarean before labor (p=0.0005). Among women with EAS injuries, those with major LAM injuries trended towards more FI, 35.3% vs. 16.7% (p=0.10) and POP, 35.3% vs. 15.5% (p=0.09), but not UI (p=1.0).Conclusion-These data support the growing body of literature suggesting that both EAS and LAM are important for fecal continence and that multiple injuries contribute to pelvic floor dysfunction.Keywords fecal incontinence; levator ani muscle; magnetic resonance imaging (MRI); pelvic floor muscle; pelvic organ prolapse; urinary incontinence INTRODUCTIONVaginal birth increases the likelihood that women will have pelvic floor dysfunction. Recent advances in pelvic floor imaging and neuromuscular testing provide evidence to pinpoint the specific anatomical and functional abnormalities caused by vaginal birth that are associated with increased occurrence of fecal incontinence (FI), pelvic organ prolapse (POP) and stress urinary incontinence (SUI).Visible damage to the pubic portion of the levator ani muscle (LAM) is one specific injury associated with vaginal delivery.(1-3) Pelvic imaging using magnetic resonance imaging (MRI) can improve our understanding of anatomic observations and clinical conditions that occur after childbirth. In a case-control study, young women with de novo SUI, nine months after a first vaginal birth, were more than twice as likely to have a LAM defect imaged on MRI compared to women without SUI (28% versus 11%).(1) However, using a different casecontrol mix of middle-aged women with and without stress SUI, the same researchers found similar rates of LAM injury in each group. (4) The relationship of LAM injury to other known injuries is not entirely clear. In a case control study of primiparous women with and without de novo postnatal stress incontinence, LAM injury was more common in those who experienced an anal sphincter rupture at delivery compared to those who did not (62% versus 17%, OR = 8.1).(2) The effect of this injury on fecal incontinence (FI), pelvic organ prolapse (POP) and stress urinary incontinence (SUI) is not fully known.The Childbirth and Pelvic Symptoms (CAPS) study assessed the prevalence and incidence of FI, POP and UI in a population of primiparous women after primary repair of clinically diagnosed 3 rd or 4 th degree sphincter tears, compared to women who underwent vaginal delivery without a tear and those who underwent a Cesarean delivery prior to labor. Two hundred and thirt...

The relationship between postpartum levator ani muscle avulsion and signs and symptoms of pelvic floor dysfunction

“…45 Our findings on objective assessment are in accordance with the literature, where POP, enlarged hiatus and LAM avulsion are inter-related. 5,6,10,14,16,46 In contrast to another study performed postpartum, 18 we found that women both with and without major LAM avulsion had significantly more faecal incontinence, without differences between groups. As shown previously we expected women with major avulsions to report more faecal incontinence, as the incidence of OASIS was higher (n = 8/30) (K. W. M. Van Delft, R. Thakar, A. H. Sultan, N. Schwertner-Tiepelmann, K. B. Kluivers [accepted].…”

“…An increase of PFMS during pregnancy, followed by a reduction in strength postpartum, has been described previously. 42 Although worsening of POP following vaginal delivery has been demonstrated previously in prospective studies, 18,41,43 this was not related to LAM avulsion. Our study revealed more anterior compartment prolapse for women with LAM avulsion.…”

“…Although the relationship between LAM avulsion and faecal [17][18][19][20] and urinary incontinence [21][22][23][24][25] has been evaluated, sexual function has not been studied in relation to LAM avulsion. We are not aware of a study in the literature that has utilised validated methods for objective and subjective assessment of PFD in relation to LAM avulsion before and after childbirth.…”

ACR Appropriateness Criteria Pelvic Floor Dysfunction

“…Determining the presence of atrophy can help predict the success of sphincter defect repair in patients being considered for surgery [60]. Concurrent abnormalities of the levator ani muscle complex are also demonstrated on MRI [61,62].…”

“…Larger genital hiatus and a greater fixed and dynamic perineal descent are seen in patients with abnormal levator muscle [79,80]. In addition, major muscle loss can be seen in combination with external anal sphincter injury on MRI in postpartum patients [61]. In patients with recurrent POP after surgery, major levator muscle defects may be a contributing factor [81][82][83][84].…”