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

! 1! Re: The evolution of levator ani muscle trauma over the first 9 months 1! after vaginal birth 2! 3! Authors: José Antonio García-Mejido1,2 4! 5! Afiliation: 6! 1Department of Obstetrics and Gynecology, Valme University Hospital, Seville, 7! Spain. 8! 2Department of Obstetrics and Gynecology, University of Seville, Spain. 9! 10! 11! Corresponding author: 12! José! Antonio! García! Mejido.,! Department! of! Obstetrics! and! Gynecology! Valme!13! University!Hospital,!Seville,!Spain.!ENmail:![email protected]!!14! 15! 16! Author's Contribution: 17! José Antonio García-Mejido: Data collection, data analysis, manuscript writing. 18! 19! 20! Funding information: None 21! 22! 23! Keywords: Levator ani . Avulsion . Hematoma . Pelvic floor . Vaginal birth . 4D 24! translabial ultrasound 25! ! 2! Re: The evolution of levator ani muscle trauma over the first 9 months 26! after vaginal birth 27! 28! Abstract: 29! 30! The disappearance of levator ani muscle(LAM) avulsions has given rise to two theories 31! that try to justify the disappearance of LAM avulsion over time (diagnostic errors or 32! possible natural healing process of LAM avulsion). It is difficult to confirm one of these 33! two theories in a study.There are two types of LAM avulsion. Type I injury is limited to 34! individual portions of the pubovisceral muscle with parts of the muscle missing, while 35! the levator arch remains intact. Type II injury consists of detachment of the catenary-36! shaped levator arch from the pubic bone due to excessive tension created in this region 37! during vaginal delivery, with loss of the normal architecture of the lateral pelvic wall 38! due to the loss of this union.These lesions have also been diagnosed by transperineal 39! ultrasound. LAM type I avulsion assessed at 6 months postpartum was shown to 40! disappear one year postpartum. Type II LAM avulsion diagnosed 6 months after 41! delivery persisted one year postpartum. They did not observe the appearance of new 42! lesions (type I and type II LAM avulsion) between the exploration carried out at 6 43! months and the modification at one year postpartum. 44! 45! Currently, the vast majority of studies that refer to the number of LAM after 46! instrumented delivery ultrasound examination was performed up to 6 months after 47! delivery. This would make us doubt whether the figures for permanent LAM avulsion in 48! operative delivery are correct. Therefore, research should be needed to resolve this issue 49! and clarify the evolution of LAM avulsion after postpartum. 50! 51! Letter ti the Editor: 52! 53! In this study we provide a new approach, currently discussed in the literature, assessing 54! spontaneous recovery from levator ani muscle (LAM) avulsion (1). The authors justify 55! the differences in LAM avulsion rates, between the first days after delivery and 6-10 56! weeks postpartum, by the presence of hematomas in the LAM (1). Hematomas ceased 57! to be visible after 6-10 weeks postpartum, coinciding with the results previously 58! published. Therefore, it is recommended not to make a diagnosis of LAM avulsion until 59! 3 months after delivery to avoid diagnostic errors. 60! ! 3! 61! However, the most important data in this study lies in the disappearance of LAM 62! avulsions between the ultrasound at 6-10 weeks and the ultrasound at 6-9 months after 63! delivery (1). These results are consistent with those previously published by other 64! authors, as indicated in the work (2). This fact has given rise to two theories that try to 65! justify the disappearance of LAM avulsion over time. The first one defends that 66! excessively early ultrasound exploration after childbirth can favor diagnostic errors (3) 67! and the second focuses on the possible natural healing process (3) of LAM avulsion 68! along weather. It is difficult to confirm one of these two theories in a study. However, 69! the work of Kim et al. (4) could help us understand a logical explanation for this 70! process. Kim et al. establishes through anatomical study and magnetic resonance 71! imaging that there are two types of LAM avulsion. Type I injury is limited to individual 72! portions of the pubovisceral muscle with parts of the muscle missing, while the levator 73! arch remains intact (4). Type II injury consists of detachment of the catenary-shaped 74! levator arch from the pubic bone due to excessive tension created in this region during 75! vaginal delivery, with loss of the normal architecture of the lateral pelvic wall due to the 76! loss of this union. (4). These lesions have also been diagnosed by transperineal 77! ultrasound (Figure 1)(2). LAM type I avulsion assessed at 6 months postpartum was 78! shown to disappear one year postpartum (2). Type II LAM avulsion diagnosed 6 months 79! after delivery persisted one year postpartum (2). They did not observe the appearance of 80! new lesions (type I and type II LAM avulsion) between the exploration carried out at 6 81! months and the modification at one year postpartum (2). 82! 83! Considering that an early exploration of the LAM after childbirth can lead to errors in 84! the diagnosis, a recent meta-analysis adjusts the suitable moments to make the diagnosis 85! of LAM avulsion (5). Rusavy et al. advise that the diagnosis of LAM avulsion should 86! be made after 6 months postpartum and in forceps deliveries after 12 months 87! postpartum (5). This conclusion could be due to the existence of recoverable LAM 88! avulsions, as the authors reflect in this work. However, I do not consider that the 89! terminology applied for LAM avulsion (partial vs. complete) is the most suitable and 90! should be replaced by type I and type II. In fact, this has been verified in the literature, 91! when we analyze the published images shown by the articles that refer to the recovery 92! of the LAM avulsion (3), we observe that the cases of recovery from the avulsion they 93! correspond to a type I LAM avulsion. 94! ! 4! 95! Currently, the vast majority of studies that refer to the number of LAM after 96! instrumented delivery ultrasound examination was performed up to 6 months after 97! delivery (5). This would make us doubt whether the figures for permanent LAM 98! avulsion in operative delivery are correct. Therefore, research should be needed to 99! resolve this issue and clarify the evolution of LAM avulsion after postpartum. 100! ! 5! References: 101! 1 Kreft M, Cai P, Furrer E, Richter A, Zimmermann R, Kimmich N. The evolution of 102! levator ani muscle trauma over the first 9 months after vaginal birth. Int Urogynecol J. 103! 2022 ; 16. doi: 10.1007/s00192-021-05034-z. 104! 2 García-Mejido JA, Sainz JA. Neurourol Urodyn. Type of levator ani muscle avulsion 105! as predictor for the disappearance of avulsion. 2020;39(8):2293-2300. 106! 3 van Delft KW, Thakar R, Sultan AH, IntHout J, Kluivers KB. The natural history of 107! levator avulsion one year following childbirth: a prospective study. BJOG. 108! 2015;122(9):1266- 73. 109! 4 Kim J, Betschart C, Ramanah R, Ashton-Miller JA, DeLancey JO. Anatomy of the 110! pubovisceral muscle origin: macroscopic and microscopic findings within the injury 111! zone. Neurourol Urodyn. 2015;34(8):774-780. 112! 5 Rusavy Z, Paymova L, Kozerovsky M, Veverkova A, Kalis V, Kamel RA, et al. 113! Levator ani avulsion: a Systematic evidence review (LASER). BJOG. 2021;10. doi: 114! 10.1111/1471-0528.16837. 115! 116! !117! ! !118! ! 6! Figure and table legend 119! 120! Figure 1: A: Type I LAM avulsion (right). B: Type II LAM avulsion (bilateral). 121! ! !122! ! 7! Figure 1: A: Type I LAM avulsion (right). B: Type II LAM avulsion (bilateral). 123! 124! 125!