1058 Iatrogenic septostomy during fetoscopic laser surgery for twin twin transfusion syndrome: risk factors and outcomes

Abstract

Iatrogenic septostomy (IOS) complicates approximately 6-20% fetoscopic laser surgery (FLS) for twin twin twin transfusion syndrome (TTTS) and is associated with early delivery. We sought to determine risk factors and perinatal outcomes associated with IOS. This is a prospective cohort study of patients with monochorionic-diamniotic twins undergoing FLS for TTTS between 2011 and 2019. IOS was defined as intraoperative observation of septostomy or the development of free-floating intervening membranes with equal echogenicity fluid in each pocket observed intraoperatively or within 24 hours of FLS. We excluded patients that underwent selective reduction and those that delivered less than 24 hours after FLS. Post-op management of IOS varied depending on the referring physicians’ practices. Indications for delivery were determined by review of hospital records. Patient characteristics and pregnancy outcomes, including indication for delivery, were compared between those with versus without IOS. Of 475 patients that underwent FLS for TTTS, 33 (6.9%) had IOS. No intraoperative variables were associated with IOS (Table 1, footnote). IOS was more likely to occur when FLS was undertaken at later gestational ages (GA, 1.6 weeks later, p < 0.01) and with increased recipient maximum vertical pockets (<0.01; Table 1). Concomitant selective intrauterine grown restriction (discordance >25%) was associated with decreased risk (p = 0.02). Regarding outcomes, IOS was associated with earlier GA at delivery (29.5 vs. 31.0 wks, p < 0.01) and shorter intervals between FLS and delivery (7.4 vs. 10.5 wks, p < 0.01; Figure). There were no differences in the indication for delivery between groups. While overall twin survival between groups was similar, composite morbidity was more common in twins following IOS (p = 0.03). IOS occurred more often at later GA, with more severe polyhydramnios with smaller growth discordance, suggestive of smaller membrane reflection areas. Outcomes are similar to those previously reporting including higher perinatal morbidity due to prematurity.View Large Image Figure ViewerDownload Hi-res image Download (PPT)