Levator ani avulsion and risk of recurrence after surgery for anterior compartment prolapse: Current status

Objective Avulsion seems to be associated with recurrence of pelvic organ prolapse (POP) following surgery. The overall prevalence of levator ani avulsion in female gender after vaginal delivery is 13-36% at the ultrasound examination (US) and 20% at MRI. Relationship between avulsion of levator ani muscle (LAM) and prolapse of pelvic floor organs is well established in literature, even if there are few studies in the current literature that investigate the relationship between LAM avulsion and risk of POP recurrence after pelvic floor surgery. The few literature reports on LAM avulsion and risk of recurrence after pelvic surgery for anterior compartment prolapse will be reviewed in this article. Methods A systematic literature review was conducted using the PubMed database. The search keyword used was “levator avulsion”. In addition these articles were hand searched for additional citations. Results This paper reviews the available data on LAM avulsion and risk of recurrence after pelvic floor surgery in 13 articles; 9 retrospective studies and 4 prospective studies. Conclusions The reported results indicate that the presence of LAM avulsion increased the risk of recurrence after pelvic floor surgery. Società Italiana di Chirurgia Colo Rettale www.siccr.org 2017; 46: 396-404 www.siccr.org 397 Introduction Pelvic organ prolapse (POP) is a common condition that occurs in 41% of women between 50 and 79 years and is one of the most common indications for gynecological surgery. However recurrent prolapse after pelvic floor surgery is still quite common. The objective of this article is to understand the role of the levator ani muscle (LAM) injury in the recurrence of prolapse after pelvic floor surgery. The first childbirth puborectalis muscle injury was documented in 1943 by Howard Gainey . Later many studies have identified the trauma of the pelvic floor consequence to vaginal delivery as the main risk factor for LAM avulsion. During vaginal delivery the levator ani muscle plays a crucial role, running into considerable distension that result in abnormal hiatal biometry and abnormal biomechanical properties of the muscle itself. LAM avulsion is the main cause of prolapse of the anterior compartment. Avulsion seems to be associated with the recurrence of prolapse after pelvic floor surgery. The risk factors involved in trauma of the levator ani and the subsequent development of genital prolapse may be congenital or acquired, as shown in the table 1. There are many clinical and instrumental definitions of levator ani injury and these are well reported in a recent review by SchwertnerTiepelmann. Commonly, LAM avulsion is a detachment of the puborectalis branch from its insertion on the inferior pubic ramus. The muscle tone decrease leads over time to an enlargement of the urogenital jatus “ballooning” with consequent prolapse of pelvic organs. Many studies in literature argue that a defect of the levator ani muscle is associated with an incidence of approximately double of genital prolapse. It was observed that women with significant genital prolapse have a chance 4 times greater of LAM avulsion than women without prolapse. In a recent Cochrane review are illustrated the different diagnostic techniques for LAM avulsion. Diagnosis is possible with clinical examination or MRI but the gold standard remains ultrasound examination (2d transperineal ultrasound, 3D ultrasound / 4D transperineal 3D transvaginal ultrasound). Nowadays surgical approach is divided in two big branches: the fascial surgery (native tissue repair such as colporrhaphy, colposuspension and sacrospinous fixation) and the mesh surgery (biological graft repair or synthetic meshes). Pelvic reconstructive surgery can be performed through the vagina or abdominally (via a traditional incision or through laparoscopy). A recent Cochrane review shows that biological graft repair or absorbable mesh provides minimal advantage compared with native tissue repair. Graft repairs have an increased risk of SUI (stress urinary incontinence) and bladder injury; native tissue repairs have a high risk of recurrence. Some studies are going on to asses safety and efficacy of polypropylene meshes. Società Italiana di Chirurgia Colo Rettale www.siccr.org 2017; 46: 396-404 www.siccr.org 398 CONGENITAL ACQUIRED Pelvic conformation Pregnancy Bone framework Childbirth Perineal muscle variations Forceps delivery Short ano-vulvar distance Long second stage of labour Collagen abnormalities Fetal macrosomia Occipito-posterior position