Fetal Surgery

Current state of fetal surgery: The field encompasses a narrow set of accepted indications—primarily twin-twin transfusion syndrome (TTTS), severe congenital diaphragmatic hernia (CDH), myelomeningocele (MMC), and select lung lesions—with most congenital defects still managed postnatally . TTTS laser photocoagulation achieves 92–94% survival of at least one twin and 75–88% dual survival in stages 1–3, with careful vascular mapping critical to avoid missed anastomoses [e1025-c9, e1025-c11, e9231-c11]. For severe left CDH (lung-to-head ratio ≤25%), fetal endoscopic tracheal occlusion (FETO) increases survival from 8–15% to 40–60%, though preterm rupture of membranes and tracheomalacia (typically resolving by 55 months) are recognized sequelae [e1025-c1, e5404-c11, e9334-c2, e9334-c7]. The MOMS trial established that open prenatal MMC repair halves shunt dependency (40% vs. 82%) and doubles independent ambulation (42% vs. 21%), with recent registry data showing uterine dehiscence reduced to 3.7% through refined technique [e1026-c34, e1026-c35, e10241-c10]. Fetoscopic MMC repair—via percutaneous or laparoscopy-assisted approaches—permits vaginal delivery and achieves comparable hindbrain reversal with delivery at 37 weeks, though long-term motor outcomes await rigorous comparison [e10241-c13, e10241-c14, e9984-c18]. Lung lesions and technical evolution: Congenital pulmonary airway malformations (CPAMs) with cyst volume ratio >1.6 carry high hydrops risk, but maternal betamethasone now rescues >50% of cases, rendering open fetal lobectomy exceedingly rare (<1 case per 5 years at major centers) [e1027-c6, e1027-c7, e1027-c8, e884-c8]. Macrocystic lesions may require thoracoamniotic shunting (70–75% survival), and EXIT procedures—though historically overused—remain reserved for CVR >2 with compressive physiology [e1027-c12, e1088-c2]. Bronchial atresia and extra-lobar sequestrations are more refractory to steroids and carry higher intervention risk [e1027-c10, e1027-c14]. For lower urinary tract obstruction (LUTO), vesico-amniotic shunting improves pulmonary outcomes but not renal function; fetoscopic laser ablation of posterior urethral valves offers etiologic diagnosis and more physiologic drainage, achieving 55% two-year survival with 73% of survivors retaining normal renal function [e6024-c36, e6024-c38]. Serial amnioinfusion with lactated Ringer's (volume = GA×10 mL) sustains lung development in renal-failure fetuses, with 88% birth survival and 70% neonatal survival in early series, though 20% chorioamnionitis risk mandates vigilance [e6017-c22, e6017-c27, e6017-c36].