No difference was observed in USI between patients with and without LAM lesions (microtrauma or macrotrauma) 36 months post-delivery.

We conclude that the phase of delivery that causes a major increase in the area of the levator hiatus area and in the levator ani muscle area is when the fetal head reaches the 4th plane of Hodge. Furthermore, data in our paper indicates that the exact moment in which the avulsion of the levator ani muscle is produced is when the bulging of the fetal head on the maternal perineum occurs.

Abbreviations: CI, confidence interval; LAM, levator ani muscle; OR, odds ratio. AbstractIntroduction: Forceps delivery is associated with a high rate of levator ani muscle (LAM) trauma (avulsion) at 35%-65% whereas data on avulsion rates after vacuum delivery vary greatly. Nevertheless, a common characteristic of all previous studies carried out to evaluate the association between instrumental deliveries (forceps and vacuum) and LAM avulsion, is the fact that characteristics of the instrumentation have not been described or evaluated. The objective of this study is to compare the rate of LAM avulsion between forceps and vacuum deliveries according to the characteristics of the instrumentation. Material and methods: Prospective, observational study, including 263 nulliparous women, who underwent an instrumental delivery with either Malmström vacuum or Kielland forceps. The characteristics of the instrumentation, position (anterior position and other position) and height of the fetal head at the moment of instrumentation (low instrumentation [vertex at +2 station] and mid-instrumentation [head isinvolved but leading part above +2 station]) were assessed. Evaluation of LAM avulsion was performed at 6 months postpartum by three-/four-dimensional transperineal ultrasound. Using the multi-view mode, a complete avulsion was diagnosed when the abnormal muscle insertion was identified in all three central slices, that is, in the plane of minimal hiatal dimensions and the 2.5-mm and 5.0-mm slices cranial to this one. To detect a 30% or 15% difference in the LAM injury rate, with 80% power and 5% α-error, we needed, respectively 42 and 99 women per study group.Results: In all, 263 nulliparous individuals have been evaluated (162 vacuum deliveries, 101 forceps deliveries). Instrumentation in an occipito-anterior position was more frequent in vacuum deliveries (75.3% vs 56.4%, P = .002), whereas other positions were more frequent in the forceps deliveries group (24.7% vs 43.6%). No statistically significant differences were noted regarding the height of the fetal head at the moment of instrumentation. No statistically significant differences were found in the presence of LAM avulsion (41.4% vs 38.6%) between vacuum and forceps deliveries.The univariate analysis of the crude odds ratio was 1.17, 95% CI 0.67-1.98, P = .70 for

The number of vacuum tractions needed to complete fetal extraction is not associated to a higher LAM avulsion rate nor with differences in levator hiatus area.

Objective: To determine if physiotherapy treatment applied to patients with levator ani muscle (LAM) avulsion identified after a vaginal delivery, reduces the LAM hiatus area. Material and Methods: A prospective observational study of 52 nulliparous (26 in the experimental and 26 in the control group). We included patients with LAM avulsion, diagnosed by 3-4D/transperineal ultrasound performed 3 months after delivery. Patients in the experimental group underwent a program of pelvic floor exercises, assisted by biofeedback and lumbopelvic stabilization exercises. Assessment of LAM was carried out at 6 and 9 months postpartum, using 3-4D/transperineal ultrasound, and taking the following measurements: levator hiatus area at rest, during Valsalva and at maximum contraction; LAM area, and thickness of right and left LAM. Results: Patients in the experimental group presented a reduction in the levator hiatus area at rest (17.0, 15.7, 15.9 cm 2 ), during Valsalva (23.0, 20.8, 19.9 cm 2 ) and at maximum contraction (15.6, 14.4 and 13.5 cm 2 ), in comparison with patients in the control group, who presented a levator hiatus area at rest of 17.4, 17.2 and 16.8 cm 2 , during Valsalva of 21.0, 20.8 and 20.3 cm 2 , and at maximum contraction of 16.6, 16.1 and 15.6 cm 2 , at 1, 6 and 9 months postpartum respectively (P < 0.05). However, no changes were appreciated in the successive examinations regarding LAM area between study groups: experimental 9.5, 8.9, 9.6 cm 2 versus 8.9, 9.0, 9.2 cm 2 in the control group. Conclusions: Physiotherapy treatment based on pelvic floor exercises with lumbopelvic stabilization exercises in patients with LAM avulsion reduces the levator hiatus area at rest, during Valsalva and at maximum contraction.