Levator trauma is associated with pelvic organ prolapse

Abstract

Objective To estimate the risk of prolapse associated with levator avulsion injury among a urogynaecological clinic population.Design Retrospective observational study.Setting Tertiary urogynaecological unit.Sample A total of 934 women seen for interview, examination using the pelvic organ prolapse quantification (POP-Q) staging system and imaging of the levator ani muscle by four-dimensional translabial ultrasound.Methods Retrospective review of charts and stored imaging data.Main outcome measures Pelvic organ prolapse stage II and higher and presence of defects of the levator ani muscle.Results After exclusion of 137 women with a history of antiincontinence or prolapse surgery, and a further exclusion of 16 women in whom either examination or imaging was impossible, we compared prolapse and imaging data in 781 women. Mean age was 53 years (range 15-89 years), and median parity was 2 (range 0-12). Women reported stress incontinence (76%), urge incontinence (69%), frequency (47%), nocturia (49%) and symptoms of prolapse (38%). Significant prolapse (stage II or higher) was diagnosed in 415 (53%) women, and 181 (23%) women were found to have levator avulsion defects. Prolapse was seen in 150/181 (83%) women with avulsion and in 265/600 (44%) women without avulsion, giving a relative risk (RR) of 1.9 (95% CI 1.7-2.1). The association was strongest for cystocele (RR 2.3, 95% CI 2.0-2.7) and uterine prolapse (RR 4.0, 95% CI 2.5-6.5).Conclusions Women with levator avulsion defects were about twice as likely to show pelvic organ prolapse of stage II or higher than those without. This effect is mainly due to an increased risk of cystocele and uterine prolapse.Keywords 3D ultrasound, avulsion, birth trauma, levator ani, pelvic floor ultrasound, pelvic organ prolapse.Please cite this paper as: Dietz H, Simpson J. Levator trauma is associated with pelvic organ prolapse. BJOG 2008;115:979-984.

Recent studies of genetic dysfunction in pelvic organ prolapse: The role of collagen defects

“…This injury occurs in up to 36% of women 72 and has been shown to be associated with prolapse, particularly in the anterior and central compartment. 70 More recently, levator avulsion defects have also been found to be strongly associated with recurrent pelvic organ prolapse after prolapse repair. [73][74][75] It is likely that the conflicting results in the published literature on the association between collagen and prolapse aetiology are complicated by the presence of major anatomical trauma related to childbirth, as these factors are often not taken into account and controlled for during the assessment of collagen integrity.…”

“…Furthermore, other factors, such as fascial fibre tearing, altered skeletal anatomy, reduced levator ani tone due to neuronal damage and levator ani avulsion following childbirth, may also contribute to prolapse development. 2,70,71 Levator avulsion defect is the traumatic muscle detachment of the puborectalis muscle from its insertion on the inferior pubic rami. This injury occurs in up to 36% of women 72 and has been shown to be associated with prolapse, particularly in the anterior and central compartment.…”

Minimal criteria for the diagnosis of avulsion of the puborectalis muscle by tomographic ultrasound

“…While this condition can be diagnosed by palpation, this requires substantial training [16,17]. Diagnosis by magnetic resonance imaging and pelvic floor ultrasound is highly repeatable [1,18].…”

“…It is clearly related to vaginal childbirth [3,4], with Forceps delivery, length of second stage and foetal size as likely risk factors [5,6]. Such trauma is associated with abnormal muscle biometry and function as well as female pelvic organ prolapse [1,2,[7][8][9]. Avulsion increases the area of the levator hiatus [5,7], the largest potential hernial portal in the abdominal envelope.…”

“…Major morphological abnormalities of the puborectalis muscle ('avulsion') are likely to be an etiological factor in the development of female pelvic organ prolapse [1,2]. It is clearly related to vaginal childbirth [3,4], with Forceps delivery, length of second stage and foetal size as likely risk factors [5,6].…”