Perinatal Outcome in Fetuses with Dislodged Thoraco-Amniotic Shunts

Fetal thoraco-amniotic shunts (TASs) can dislodge in utero, migrating internally into the fetal thorax or externally into the amniotic cavity. Our objective was to evaluate the perinatal and long-term outcome of fetuses with TAS dislodgement and conduct a review of the literature.

This is a retrospective review of all TAS inserted for primary pleural effusions and macrocystic congenital pulmonary airway malformations (CPAMs) in a tertiary fetal medicine center (1991-2020). Antenatal history, procedural factors, and perinatal and long-term outcomes were reviewed in all fetuses with dislodged shunts and compared to fetuses with shunts that did not dislodge.

Of 211 TAS inserted at a mean gestational age of 27.8 weeks ± 5.47 (17.4-38.1 weeks), 187 (89%) were inserted for pleural effusions and 24 (11%) for macrocystic CPAMs. Shunts dislodged in 18 fetuses (8.5%), 17 (94%) of which were for pleural effusions. Shunts migrated into the chest wall/amniotic cavity or into the thorax among 7/18 (39%) and 11/18 (61%) fetuses, respectively. Eleven (61%) fetuses were initially hydropic, which resolved in 8 (72%) cases. Effusions were bilateral in 9 (50%), amnioreduction was required in 6 (33%), and fetal rotation in 8 cases (44%). Four (22%) fetuses underwent repeat shunting, 12 (67%) neonates required ventilatory support, and 2 (11%) neonates required chest tubes. There was no significant difference in technical factors or outcomes between infants with shunts that dislodged and those that did not. Among 11 intrathoracic shunts, 2 (18%) were removed postnatally and the remainder are in situ without any shunt-related or respiratory complications over a follow-up period of 9 months to 22 years.

TAS dislodged antenatally in 8.5% of fetuses, with 2/3 of shunts migrating into the thorax, and nearly 25% requiring re-shunting. Retained intrathoracic shunts were well tolerated and may not necessarily require surgical removal after birth.