211: Chorioamniotic separation after prenatal myelomeningocele repair

Abstract

To assess the risks associated with development of CAS after prenatal MMC repair We conducted a retrospective cohort study of patients who underwent open or fetoscopic prenatal MMC repair from December 2011-May 2018. Open repair technique was performed as reported in the MOMS Trial. Fetoscopic repair was performed using uterine CO2 insufflation, two or three ports, and an exteriorized uterus. Perinatal outcomes of patients who developed CAS after prenatal MMC repair were compared with those of patients who did not develop CAS. Degree of CAS was classified as mild if CAS occupied <25% of uterine surface area, moderate if 25-50%, or severe if >50%. Comparisons between cases with and without CAS were performed using Student's t-test, Chi-square, or Fisher’s exact test. Logistic regression analysis was used to determine risk of developing CAS, PPROM, or preterm delivery. Of 73 patients who underwent prenatal MMC repair, 24 (32.9%) developed CAS. CAS was detected at median of 28.9 (25.4 – 37.6) weeks gestation and 4 (0.4 – 12.6) weeks post-surgery. 70.8% of CAS cases were identified after fetoscopic repairs and 29.2% after open repairs (p=0.05). Development of CAS after fetoscopic repairs was independent of number of ports (3 ports: 35.3% vs. 2 ports: 64.7%; p=0.7) or maximal uterine pressure used (CAS: 11.9±1.7 mmHg vs. no CAS: 11.8±1.9 mmHg; p=0.7). Four variables were assessed for increased risk of developing CAS. Anterior placenta was the only variable with significant predictive value (p=0.03; OR: 3.23, 95% CI: 1.1-18.2). Fetoscopic repair, duration of surgery >3 hours, and use of three ports did not significantly increase risk of developing CAS. Cases with CAS developed PPROM 5.2 times more frequently than cases without CAS (95% CI:1.5-18.3; p<0.01). Cases of PPROM preceded by CAS occurred at later gestational age than those not preceded by CAS. A trend was noted for an association between CAS and placental abruption. When cases of moderate or severe CAS (n=11) were compared with mild CAS cases (n=12; severity of 1 case could not be assessed) at time of diagnosis, a trend for longer interval between CAS and delivery was observed in mild cases [7.8 (1.3-12.28) weeks vs. 2 (0.1-13.2 weeks); p=0.02]. Development of CAS increases the risk of adverse perinatal events. Efforts should be taken to reduce its incidence after prenatal MMC repair.