Association of amnioinfusion volume at the time of surgery for twin-twin transfusion syndrome and latency to delivery.

OBJECTIVE: To evaluate the impact of amnioinfusion and other peri-operative factors on pregnancy outcomes in the setting of Twin-twin transfusion syndrome (TTTS) treated via fetoscopic laser photocoagulation (FLP). METHODS: Retrospective study of TTTS treated via FLP from 2010 to 2019. Pregnancies were grouped by amnioinfusion volume during FLP (<1 L vs. ≥1 L). The primary outcome was latency from surgery to delivery. An amnioinfusion statistic (AIstat) was created for each surgery based on the volume of fluid infused and removed and the preoperative deepest vertical pocket. Regression analysis was planned to assess the association of AIstat with latency. RESULTS: Patients with amnioinfusion of ≥1 L at the time of FLP had decreased latency from surgery to delivery (61 ± 29.4 vs. 73 ± 28.8 days with amnioinfusion <1 L, p < 0.001) and increased preterm prelabor rupture of membranes (PPROM) <34 weeks (44.7% vs. 33.5%, p = 0.042). Amnioinfusion ≥1 L was associated with an increased risk of delivery <32 weeks (aRR 2.6, 95% CI 1.5-4.5), 30 weeks (aRR 2.4, 95% CI 1.5-3.8), and 28 weeks (aRR 1.9, 95% CI 1.1-2.3). Cox-proportional regression revealed that AIstat was inversely associated with latency (HR 1.1, 95% CI 1.1-1.2). CONCLUSION: Amnioinfusion ≥1 L during FLP was associated with decreased latency after surgery and increased PPROM <34 weeks.

Effect of allograft patch closure on incidence of spinal inclusion cyst formation following open fetal myelomeningocele repair.

OBJECTIVE: The aim of this study was to evaluate the incidence of spinal inclusion cyst (sIC) formation after open fetal myelomeningocele (fMMC) repair and the effect of dural patch closure. METHODS: The authors conducted a retrospective review of patients who underwent open fMMC repair at their institution between March 2011 and June 2020. All patients met the criteria for intervention defined by the Management of Myelomeningocele Study (MOMS). The primary outcomes investigated were development of sIC and need for surgical intervention. Secondary outcomes included need for CSF diversion, extent of reversal of hindbrain herniation, and ambulatory status. RESULTS: Of 56 patients who underwent open fMMC repair, 52 had adequate spinal imaging for review. Twelve of these patients (23%) developed sIC (95% CI 0.11-0.35). Six patients experienced symptoms and required surgical detethering with sIC resection. Six additional patients had evidence of sIC on surveillance MRI but remained asymptomatic. The authors found a statistically significant relationship between the use of a dural allograft patch and sIC formation (p = 0.05). In terms of sIC development, there was no statistically significant difference between patients who underwent primary closure and those who received an allograft at the level of the fascia (p = 0.34) or skin (p = 0.26). The rate of hydrocephalus requiring CSF diversion was 52%. Interestingly, 98% of patients had improvement in extent of hindbrain herniation. Dural patch closure did not have any effect on the rate of progressive hydrocephalus (p = 0.33) or degree of reversal of hindbrain herniation (p > 0.99). CONCLUSIONS: This study suggested that children with prenatally repaired MMC are at higher risk for development of sIC and associated symptoms than those who undergo postnatal repair. The presentation of symptoms was also earlier in these patients than previously reported after postnatal repair. The use of a dural allograft patch appears to have a positive correlation with sIC formation. Future investigations evaluating the incidence of sIC after fetoscopic MMC repair, in which primary dural closure typically cannot be achieved and a dural patch is most often utilized, will be helpful in facilitating prenatal counseling for patients considering fetal intervention.

Comparison of Pregnancy Outcomes of Previable and Periviable Rupture of Membranes After Laser Photocoagulation for Twin-Twin Transfusion Syndrome.

OBJECTIVE: To describe the pregnancy outcomes of patients who experienced previable and periviable prelabor rupture of membranes (PROM) after the treatment of twin-twin transfusion syndrome. METHODS: We conducted a retrospective cohort study of patients whose pregnancies were complicated by twin-twin transfusion syndrome who were treated with fetoscopic laser photocoagulation at a single fetal center and subsequently experienced PROM from April 2010 to June 2019. Outcomes were infant survival and latency from PROM to delivery. Patients were grouped by gestational age at PROM (before 26 weeks of gestation and 26 weeks or later). The group with PROM before 26 weeks of gestation was stratified by gestational age at PROM for further description of outcomes. RESULTS: Two-hundred fifty of 653 patients (38%) developed PROM, 81 before 26 weeks of gestation and 169 after 26 weeks of gestation. In the setting of PROM before 26 weeks of gestation, the rate of survival of both twins to neonatal intensive care unit (NICU) discharge was 46.3%, compared with 76.9% in the setting of PROM at 26 weeks of gestation or later ( P <.001); the survival rate of at least one twin was 61.2% and 98.5%, respectively ( P <.001). Fourteen, 22, and 45 patients experienced PROM at 16-19 6/7, 20-22 6/7, and 23-25 6/7 weeks of gestation, respectively. Survival of both twins and at least one twin to NICU discharge was 25.0%, 47.4%, 52.8% (for two) and 33.3%, 47.4%, and 77.8% (for at least one), respectively, among those groups. Fifty-seven of the 81 patients with PROM before 26 weeks of gestation experienced a latency longer than 48 hours. In the setting of PROM before 26 weeks of gestation, when latency lasted longer than 48 hours, overall survival was improved (69.6% vs 53.7%, respectively, P =.017). With latency longer than 48 hours and PROM at 16-19 6/7, 20-22 6/7, and 23-25 6/7 weeks of gestation, survival of both twins to NICU discharge was 60.0%, 61.5%, and 60.7%, respectively, and survival of at least one twin was 80.0%, 61.5%, and 85.7%, respectively. CONCLUSION: Earlier gestational age at PROM after laser photocoagulation is associated with longer latency but lower rates of survival. When PROM occurs before 26 weeks of gestation and latency exceeds 48 hours, rates of neonatal survival are significantly improved.

Fetoscopic Multilayer, Dural Patch Closure Technique for Intrauterine Myelomeningocele Repair: 2-Dimensional Operative Video.

Myelomeningocele (MMC) is the most common open neural tube defect associated with long-term survival. In 2011, The Management of Myelomeningocele Study (MOMS) trial demonstrated that fetal repair for MMC reduced the rate of shunted hydrocephalus and improved developmental, motor, and ambulation outcomes at 30 mo compared to postnatal intervention.1 Recent studies have demonstrated the safety and feasibility of fetoscopic MMC repair as well as reduction in preterm birth, lower risk of uterine dehiscence, and the option of vaginal delivery with this approach compared to open fetal repair.2-4 The patient is a 25-yr-old female, G4 P2, who presented at 20 wk's gestation with ultrasound findings concerning for MMC and Chiari II malformation. These findings were further corroborated with fetal magnetic resonance imaging. After extensive prenatal counseling in a multidisciplinary fashion and discussion regarding risks and benefits of prenatal closure of the MMC, the patient chose to undergo prenatal repair and surgical consent was obtained. At 25 wk's gestation, the patient underwent a fetoscopic multilayer closure with dural patch repair using a standardized, 3-port, carbon dioxide insufflation technique for the intrauterine treatment of MMC without any postoperative complications. The duration of the entire procedure was 275 min. At 36 wk's and 1 d's gestational age, the patient had a spontaneous vaginal delivery, resulting in a healthy male newborn. The surgical site was well healed without complications, and follow-up radiographic imaging was reassuring. This edited, 2-dimensional operative video highlights the key steps of the fetoscopic closure with follow-up postnatal clinical and radiographic outcomes.