Case Report: Successful fetoscopic release of pseudoamniotic bands in twin-to-twin transfusion syndrome and twin reversed arterial perfusion sequence: report of two rare cases and review of the literature.

BACKGROUND

Pseudoamniotic band syndrome (PABS) is an iatrogenic amniotic disruption sequence that may occur after invasive fetal procedures, including fetoscopic laser therapy and amniocentesis. Fetoscopic release of the bands has been reported in singleton pregnancies, but it remains rare in twin pregnancies after intrauterine fetal surgery. This study aimed to report two rare cases of PABS occurring after invasive fetal interventions-one for twin-to-twin transfusion syndrome (TTTS) and one for twin reversed arterial perfusion (TRAP) sequence-both of which were successfully managed by fetoscopic band release, and to review the clinical characteristics of PABS in TTTS.

METHODS

We describe one rare case off fetal abdominal constriction caused by amniotic bands following TTTS fetoscopic surgery, and one case of PABS in TRAP sequence after microwave ablation and amniocentesis. Both cases were successfully treated in utero via subsequent fetoscopic band release later. A literature review was conducted on PABS cases after TTTS intervention, comparing cases managed expectantly versus those treated with fetoscopic release.

RESULTS

We reported two cases of PABS with constriction of the fetal abdomen and ankle, respectively, treated by fetoscopic band release, and both cases achieved successful outcomes after fetoscopic band release. A literature review identified 50 reported PABS cases after TTTS treatment. PABS occurred predominantly in recipients (78.0%, 39/50 cases), primarily affecting fetal limbs (88.2%, 45/51 fetuses). Antenatal detection was low (20.0%, 10/50 cases), and without intervention, 9.5% (4/42 fetuses) developed fetal limb amputation. Including our case, only 8 PABS cases in TTTS have undergone fetoscopic release, with a median interval of 4.3 weeks post-TTTS fetoscopic laser. The median GA at fetoscopic release surgery was 23.5 (range, 21-27.4) weeks, with a median interval of 5.6 (range, 0.8-11.9) weeks between fetoscopic release and delivery (at 30.7 weeks; range, 24.7-34.9). Of these, 37.5% (3/8) of the newborns required further plastic surgery after birth, but all fully recovered functionally without amputation.

CONCLUSION

Serial ultrasound surveillance after fetal interventions should include PABS assessment, particularly 4 weeks post-procedure. Although antenatal diagnosis remains challenging, fetoscopic band release appears technically feasible in twin pregnancies and potentially beneficial in carefully selected, antenatally diagnosed cases, but the evidence remains limited and vulnerable to publication bias.