Levator ani avulsion: a Systematic evidence review (LASER).

Area of Science:

• Obstetrics and Gynecology
• Pelvic Floor Imaging
• Maternal Health

Background:

• Levator avulsion (LA) is a significant childbirth injury with variable reported incidence.
• Limited research exists on the specific risk factors influencing LA occurrence.

Purpose of the Study:

• To determine the incidence rate of levator avulsion (LA) based on delivery mode.
• To analyze LA incidence across different imaging modalities and diagnostic timings.
• To investigate the laterality of avulsion in relation to birth type.

Main Methods:

• A systematic literature search was conducted across major medical databases (MEDLINE, EMBASE, CINAHL, AMED, MIDIRS) up to April 2019.
• Included were 37 non-randomized studies involving 5594 women where LA was assessed via imaging post-birth.
• Meta-analyses were performed using RevMan v5.3, with specialized statistical packages for imaging analysis.

Main Results:

• LA incidence rates varied significantly: 1% (cesarean), 15% (spontaneous), 21% (vacuum-assisted), and 52% (forceps).
• Spontaneous birth carried a 10.69-fold higher odds of LA compared to cesarean.
• LA was more common unilaterally after spontaneous and vacuum-assisted births; higher incidence observed with assessment within 4 weeks postpartum.

Conclusions:

• Forceps delivery presents the highest risk for levator avulsion (52%), while cesarean delivery has the lowest (1%).
• Ultrasound and MRI are comparable for diagnosing LA.
• Early postpartum diagnosis (within 4 weeks) is associated with higher LA detection rates.