Quantification of 3/4D ultrasound pelvic floor changes induced by postpartum muscle training in patients with levator ani muscle avulsion: a parallel randomized controlled trial.

Background: We believe that physiotherapy with muscle training (MT) of the postpartum pelvic floor may lead to a change in the clinical management of patients with avulsion of the puborectal portion of the levator ani muscle (LAM). Our objective is to assess whether physiotherapy with MT of the postpartum pelvic floor in patients with LAM avulsion produces changes in pelvic floor morphology evaluated by 3/4D transperineal ultrasound.

Methods: This parallel randomized controlled trial (RCT) included 97 primiparous patients. A study was conducted in three parts. In the first part (3 months postpartum), primiparous patients with LAM avulsion were recruited, and the levator hiatus and the LAM areas were measured using 3/4D transperineal ultrasound. In the second part (3 to 6 months postpartum), patients were randomized into two groups, with one undergoing rehabilitation (experimental group) and another without rehabilitation (control group). At the end of 6 months, a new transperineal ultrasound was performed. In the third part (9 months postpartum), the levator hiatus and LAM dimensions were analyzed again. The RCT was registered at ClinicalTrials.gov (NCT03686956). Project PI16/01387 funded by Instituto de Salud Carlos III (Spain) integrated in the national I+D+i 2013-2016 and cofounded by the European Union (ERDF/ESF, "Investing in your future").

Results: A total of 92 completed the study, including 46 patients in the experimental group and 46 in the control group. The experimental group had a greater LAM area at 6 months (9.2±1.9 7.6±2.1 cm, P=0.008; 95% CI: 0.6-3.0) and 9 months after labor (9.4±2.7 7.6±2.0 cm, P=0.012; 95% CI: 0.4-3.2), which was not observed at 3 months postpartum (8.3±1.6 7.5±2.3 cm; P=0.183; 95% CI: 0.39-1.99). The levator hiatus area decreased more in the experimental group in almost all comparisons. The most significant change occurred from 3 to 6 months during the Valsalva maneuver (-3.92±5.12 0.45±3.06 cm; P<0.005; 95% CI: 2.64-5.00).

Conclusions: Women with a rehabilitated LAM through physiotherapy showed a significant reduction in the levator hiatus area during Valsalva while receiving in-person physical therapy (3 to 6 months after delivery). These differences did not persist once physical therapy was completed (6 to 9 months after delivery).

Trial Registration: ClinicalTrials.gov identifier NCT03686956.