Does the Epi-No® Birth Trainer reduce levator trauma? A randomized controlled trial Shek, KL, Chantarasorn V, Langer S, Phipps H, Dietz HP

Trisha Jenkyns 8-8-2012

Primary Aim:
To evaluate whether antepartum use of a birth trainer (Epi-No®) may reduce levator trauma.

Null hypothesis was: “Antepartum use of the Epi-No® device does not reduce the incidence of trauma to the puborectalis muscle”.

 

“The Epi-No® Birth Trainer (Starnberg Medical, Tecsana GMBH, Muenchen, Germany) was designed by a German doctor, Wilhelm Horkel. He designed an inflatable silicon balloon coupled to a pressure display hand pump to gradually stretch the vagina and perineum in late pregnancy to reduce the risk of perineal trauma during vaginal birth. To date, the limited data available in the literature seem to support his observation.”

Study Design: Randomized controlled pilot study

Subjects

200 women with singleton pregnancy

146 women returned for follow- up 5.6 months (range 2.3–22.1) post partum

Methods:

200 nulliparous women were recruited at the antenatal clinic of two tertiary hospitals between July 2007 and July 2009 in Australia.  Inclusion criteria: singleton pregnancy, 18 years old or older and aiming for vaginal delivery.  Women were then computer randomized into intervention (Epi-No) & control groups.  Assessors were blinded to which group each patient was assigned.

4D Translabial US: Volume acquisition was performed:

·    At rest

·    On maximum Valsalva maneuver (at least 3 Valsalva maneuvers were performed for each patient; the best or the maneuver with the greatest descent was used for analysis of microtrauma)

·    On maximum pelvic floor muscle contraction (PFMC)

Epi-No group: Women were instructed to use the device from 37 weeks until delivery up to two 20-min sessions every day. The balloon is inserted 2/3’s into the vagina and inflated to the level of personal comfort and left in place until completion of the session. The balloon is expelled out by maternal effort (while still inflated) at the end of the session to allow measurement of balloon diameter. Women were encouraged to gradually increase the size of the balloon from session to session.

All participants were invited for F/U 3 months postpartum.  At the F/U appointment the ultrasound assessment was repeated again with the assessor blinded to all delivery data.  Women were asked not to divulge any information regarding their delivery and group allocation until after the US assessment.

Results

·         Of the 200 participants, 96 were randomized to the control group, and 104 to the Epi-No® group. There was no significant difference in demographic and delivery variables.

o    82 returned in Epi-No group and 64 returned in control group

·         Data analysis was performed several months after the US assessment.

·         Hiatal area was measured at the plane of minimal hiatal dimension (in the mid-sagittal plane)

·         Microtrauma was defined as a 20% peripartum increase in hiatal area on Valsalva or irreversible over-distension of the levator hiatus

o    Authors considered any increment in hiatal areas greater than 20% could be reasonably assumed to be the effect of childbirth.

o    Hiatal area on Valsalva instead of area at rest was used in the definition as it has been shown in previous studies to be more strongly associated with pelvic organ descent

·         Macrotrauma or avulsion was determined by looking at volumes on PFMC, or at rest in those patients who failed to perform PFMC (n = 3). Tomographic US slices were obtained in the axial plane.

o    Levator avulsion was diagnosed if three central slices showed a clearly abnormal muscle insertion.  (methodology has been previously validated)

o    Ultrasound diagnosis of levator avulsion (kappa greater than or equal to 0.7) has also been previously demonstrated with good repeatability

·         A subgroup analysis on women with cesarean section was performed in order to test for any possible undesirable effect of the Epi-No® Birth Trainer on hiatal biometry and pelvic organ support in women after abdominal delivery

o    Since it is a possible concern that the Epi-No® device may have permanent effects on the pelvic floor in women who do not deliver vaginally; a subgroup analysis was done for women who delivered by C-section.  No significant differences in peripartum changes were found between the control and Epi-No® groups (in hiatal areas and pelvic organ descent).   BUT... the group sizes were very small, larger sample sizes are needed to confirm these reassuring findings!!

·         11 women in the control group used the Epi-No® before birth and 8 women in the Epi-No® group did not use the birth trainer. To account for these crossovers, a treatment received analysis was performed, revealing largely similar findings compared to the modified ITT analysis!!

o    For women in the Epi-No® group who did not use the device …the risk of microtrauma reduced from 38% to 26% (for women who used it < or equal to 20X) and to 17% (for women who used it >20X).  “However, this finding did not reach statistical significance (P=0.4), likely due to a lack of power.”

Discussion:

The article states: “Despite the fact that our study failed to demonstrate a statistically significant difference in the incidence of levator trauma between the control and Epi-No® group, the result is noteworthy for the 53% reduction in avulsion in the Epi-No® group in the modified intention to treat and 42% in the treatment received analysis. It is likely that our pilot study was insufficiently powered. Based on the findings of this pilot study a power calculation revealed that an intention to treat analysis would need a sample size of 660 women to show a reduction in the incidence of avulsion by 50% as significant, and recruitment is continuing towards this target.”

 

·         The effect of the Epi-No® device on the incidence of microtrauma was not obvious in the modified ITT analysis. But the use of the Epi-No® device may affect results, as the risk of microtrauma reduced as it was used more.

·         In the treatment received analysis there was a 30% decrease in the incidence of microtrauma in women who actually used the birth trainer before delivery, irrespective of the initial group allocation.

·         Compliance should be stressed to participants to increase the power of future studies.

Limitations (not all are listed here):

·         Valsalva maneuver was not standardized which implies that Valsalva strength could be a potential confounder of the assessment of hiatal area on Valsalva. According to other studies, standardizing the Valsalva maneuver has been largely unsuccessful.

·         Study showed a weak trend towards a lower incidence of levator avulsion and irreversible over-distension in women allocated to the Epi-No® group (for those who actually used the device).

·         Not FDA approved in the United States…In looking into why it is not FDA approved I found that the device was previously FDA approved but due to an adverse reaction, the FDA has pulled the product off the market. As far as I know it is presently available in Canada, Australia, New Zealand, Israel & the UK. You may want to keep your eyes open for the RCT and if the results are favorable, the product may return to the U.S.

Clinical Application:

Even though the device is not FDA approved for the U.S.; the concept may be possible to apply. 

Comments:

There was much discussion around the actual & potential benefits.

It was thought that the most benefit is likely from sensory awareness, the practice of expelling the device and the confidence gained; not so much from the actual stretch. A concern was stated that too much stretch might occur with the use of the device.  Obviously more research is needed.