Incidence of pelvic floor injury after a first normal vaginal delivery in women with and without a mediolateral episiotomy (EPILEVA study)

The levator ani muscle, also called the pelvic floor, is attached to the
internal surface of the true pelvis and is subdivided into three parts
according to their attachments and pelvic viscera to which they are related,
namely ileococcygeal, pubococcygeal and puborectal muscle. The pelvic floor is
funnel shaped, with the puborectal muscle as the most caudal and central
component.
MRI and three dimensional (3D) and four dimensional (4D) transperineal
ultrasound technique can visualize abnormalities of the levator ani muscle or
pelvic floor.(1,4,20)
Whilst MRI is not widely available, invasive and expensive, 3D/4D transperineal
ultrasound offers the same advantages, is less expensive and is well tolerated
by the patients. With the increasing experience in these dynamic imaging
techniques, new insights have been gained on pelvic floor dysfunction and the
impact this has on symptoms and anatomical abnormalities. Anatomical
abnormalities are prescribed as a detachment of the puborectalis part at its
origin on the pubic bone and are also called a levator avulsion (figure 1).
These avulsions can occur either unilateral or bilateral. Most authors assume
that levator avulsion happen during crowning of the fetal head.(21)
Lien et al(22) showed that a remarkable degree of distension of levator ani
has to appear during labour (figure 2). This study showed that the
mediococcygeus muscles undergo the greatest stretch of the levator ani muscle
during vaginal birth and therefore at that time are at the greatest risk to
develop injury. The diameter of the fetal head is around 9 cm, and assuming
that the size of a normal *non pregnant female* is around 2.5 cm, means that
the tissue of the pelvic floor, i.e the levator ani has to stretch 3.54 in
length and fourfold in proportion to the ratio of the diameter of the hiatus of
the levator ani. These findings were confirmed in a recent study in which 227
nulliparous pregnant women were examined before and after childbirth. In this
study the levator ani muscle dilated between 25% to 245% during
parturition.(23)
Using MRI, DeLancey et al(4) were the first to report a relation between
levator ani avulsion and vaginal deliveries. Levator ani avulsion was
identified in 20% of women after their first vaginal delivery. No pelvic floor
abnormalities were found in nulliparous women. Dietz et al(4,20) reported
similar findings using 3D transperineal ultrasound. Levator ani avulsion was
identified in up to 36 percent of the women after vaginal delivery. They found
no pelvic floor abnormalities in women after Caesarean section. These findings
indicate that pelvic floor damage is most likely caused by vaginal delivery.
Furthermore, it has been proven that these defects are significantly associated
with pelvic organ prolapse and the risk of developing recurrence of prolapsed
after surgery.(24) Pelvic organ prolapse is a common condition and the
estimated prevalence is around 40%. Childbirth is considered to be a risk
factor for developing pelvic organ prolapse by 4 to 11 times and stress urinary
incontinence by 2.7 times. One in three women complaining of pelvic organ
prolapse symptoms require surgery and 30% of these operations require a
re-operation at some stage.(25) Re-operation usually includes a more extensive
procedure, such as a laparoscopic sacrocolpopexy or Mesh Implants.
Vaginal delivery may injure the levator ani in a number of different patterns
sometimes termed *defects*.(4) For a long time it has been difficult to examine
the pelvic floor in young asymptomatic nulliparous women due to the inherent
limitations of magnetic resonance imaging and the logistic problems of
performing MRI. With the introduction of 3D pelvic floor ultrasound imaging
since the 1990s a non invasive and more practical technique for assessment of
levator ani morphology became possible.(1,26) Transperineal ultrasound is an
easy accessible investigation and an objective non-invasive method to examine
levator ani avulsion. Several studies have shown that this investigation is
reliable and repeatable. (27-28)
Prevention of levator avulsion is important, because until now it is not
possible to repair this damage. Prevention is possible by identifying risk
factors for developing levator avulsion.
Previous research showed that a mediolateral episiotomy during operative
vaginal delivery and restrictive use during normal vaginal delivery can protect
against anal sphincter injuries another type of pelvic floor injury.(6-9)
A mediolateral episiotomy in certain studies showed also to be preventive for
levator avulsion, but other studies show no effect or an increase in levator
avulsions.(10-14) The potential benefits of mediolateral episiotomy need to be
weighed against potential adverse effects resulting from this procedure,
including unsatisfactory anatomic results (eg, skin tags, asymmetry, fistula,
narrowing of introitus), increased blood loss, increased postpartum pain,
higher rates of infection and dehiscence and sexual dysfunction.(15-19)
To examine this hypothesis we aim to investigate differences in incidence of
levator avulsion and morphological abnormalities of the levator ani on 3D/4D
transperineal ultrasound volumes and urogynaecological complaints, in women
after a first, normal vaginal delivery with and without a mediolateral
episiotomy.

Primary Objective
Difference in incidence of an avulsion injury and morphological changes of the
levator ani muscle after a first normal vaginal delivery between participants
with and without a mediolateral episiotomy.

Secondary Objective
Changes in quality of life and pelvic floor symptoms questionnaires between
both groups.
Differences in angle and length of the mediolateral episiotomy and incidence of
levator avulsion.

Retrospective observational cohort study

Women who underwent a first normal vaginal delivery between January 2012- May
2013 will be invited to participate and women between May 2013- May 2014 will
be asked permission to contact them after their normal vaginal delivery with or
without mediolateral episiotomy to invited them to participate in our study.
This permission is obtained prior to their delivery around 37 weeks gestation,
directly after the delivery or 6 weeks after delivery at their postpartum
check-up. A mediolateral episiotomy was performed by the women*s obstetrician
or midwife for medical reasons during labour. The investigators have not been
involved in the participants* delivery. Women that gave prior permission will
be called 6 months after delivery to invited them to participate. 200
participants divided in two groups, women with and without a mediolateral
episiotomy, will be invited to participate 6 months after delivery to fill in
an anonymized standardized questionnaire on urogynaecological complaints and
impact of complaints on quality of life. After this the participants will
undergo one additional exam, measurement of angle en length episiotomy and a
3D/4D transperineal ultrasound. This will take about 30 minutes. No further
efforts of the participants are required.

Duration of study
18 months

Setting of study
Outpatient clinic Amphia Hospital Breda

Participants in both groups will fill out a standardized questionnaire on
urogynaecological complaints.
All participants will be asked to visit the outpatient clinic for one
additional examination: dynamic 3D/4D transperineal ultrasound. 3D/4D
transperineal ultrasound is a non-invasive, safe imaging method without any
risks for the participants. The exam will be performed in a supine position
after voiding. The participant will be asked to take off their underwear. The
angle and the length of the mediolateral episiotomy will be measured with a set
triangle. During the examination the transducer will be covered with a glove
and some ultrasound gel placed on the outside of the perineum. Imaging volumes
will be acquired in rest, contraction and at Valsalva. This examination takes
approximately 30 minutes.
As we only use 3D/4D transperineal ultrasound no harmful adverse effects of
this study is expected on the maternal health.
There are no benefits for the participants. The results of the study may
contribute to prevent injuries in a future population.