Levator ani avulsion: a Systematic evidence review (LASER)

Abstract

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.

How does the type of delivery affect pelvic floor structure? MRI parameter-based anatomical study

“…This suggested that mechanical forces have an effect on the levator ani, which is the biggest support factor of the pelvic floor during the delivery process. In support of our results, various studies have shown that vaginal delivery creates a defect on the levator ani muscle, especially in the puborectalis muscle [22,23].…”

Multicenter study of the evolution of different types of avulsion over the 12 months after delivery

“… 12 , 14 , 15 A recent systematic review advised practitioners to avoid performing imaging tests during the early postpartum period owing to the risk of overdiagnosis; consequently, it seems reasonable to postpone a final diagnosis until 6 months after delivery or until more than 12 months after forceps‐assisted delivery. 27 Furthermore, it has been suggested that the current criteria for the diagnosis of LAM avulsion may not be appropriate after the first delivery, 15 because the diagnosis may depend on the clinician. Therefore, we performed a multicenter study with the objective of verifying that LAM avulsion occurs in a similar way regardless of the center, examiner, or type of ultrasound used.…”

Re: The evolution of levator ani muscle trauma over the first 9 months after vaginal birth

“…Currently, the vast majority of studies that refer to the number of LAM after instrumented delivery ultrasound examination was performed up to 6 months after delivery. 5 This would make us doubt whether the figures for permanent LAM avulsion in operative delivery are correct. Therefore, research should be needed to resolve this issue and clarify the evolution of LAM avulsion after postpartum.…”

“…2 Considering that an early exploration of the LAM after childbirth can lead to errors in the diagnosis, a recent meta-analysis adjusts the suitable moments to make the diagnosis of LAM avulsion. 5 Rusavy et al advise that the diagnosis of LAM avulsion should be made after 6 months postpartum and in forceps deliveries after 12 months postpartum. 5 This conclusion could be due to the existence of recoverable LAM avulsions, as the authors reflect in this study.…”

“…5 Rusavy et al advise that the diagnosis of LAM avulsion should be made after 6 months postpartum and in forceps deliveries after 12 months postpartum. 5 This conclusion could be due to the existence of recoverable LAM avulsions, as the authors reflect in this study. However, I do not consider that the terminology applied for LAM avulsion (partial vs. complete) is the most suitable and should be replaced by type I and type II.…”