Supplementary Material for: Prenatal Risk Factors and Outcomes of Pseudoamniotic Band Sequence Following Fetoscopic Laser Surgery, Systematic Review and Meta-analysis

Introduction: To investigate prenatal risk factors and perinatal outcomes for pregnancies involving pseudoamniotic band sequence (PABS) after fetoscopic laser surgery (FLS) for twin-to-twin transfusion syndromes (TTTS) and compare outcomes between those undergoing fetoscopic band release vs. not. Methods: We conducted a systematic search of PubMed, Scopus, and Web of Science on studies reporting PABS following FLS for TTTS. A meta-analysis of pooled proportions was conducted. Results: There were 16 studies covering 47 pregnancies complicated by PABS following FLS, mostly case series and case reports. The incidence of PABS was 2%, with the recipient twin affected in 94% of the cases. Pregnancies complicated by PABS were associated with inter-twin septostomy in 32% and chorioamniotic separation (CAS) in 90%. The mean gestational age (GA) at FLS and delivery were 17.7 and 30.9 weeks respectively. Preterm premature rupture of membranes (PPROM) happened in 62% of pregnancies. The risk of preterm birth (PTB) <34 weeks, <32 weeks, and <28 weeks were 94%, 67%, and 31%, respectively. There were 41% fetal demises and 64% live births among the affected fetuses. Results of fetoscopic band release versus not were comparable, including GA at delivery, PPROM, and PTB at 32 weeks. It was noted that the likelihood of PTB by 28 weeks (67% vs 23%) and fetal death (50% vs 39%) were higher in the band release group. It was similar between groups in terms of postnatal amputation. Conclusion: PABS causes amputations or fetal death in more than one-third of cases. Pregnancies with an inter-twin septostomy, CAS, advanced TTTS staging, and early GA are more likely to experience PABS. In addition, more than a third of FLS-treated TTTS resulted in PTB and PPROM. PABS cases with prenatal band release showed higher rates of PTB and fetal death, but the data were from small, heterogeneous studies.

引言：本研究旨在探究双胎输血综合征（twin-to-twin transfusion syndromes, TTTS）患者接受胎儿镜激光手术（fetoscopic laser surgery, FLS）后并发假羊膜带序列（pseudoamniotic band sequence, PABS）的产前危险因素及围产期结局，并对比接受胎儿镜带松解术与未接受该手术者的结局差异。方法：我们对PubMed、Scopus及Web of Science数据库中报道TTTS经FLS治疗后并发PABS的相关研究进行系统性检索，并开展了合并率的Meta分析。结果：共纳入16项研究，涉及47例TTTS经FLS治疗后并发PABS的妊娠病例，其中多数为病例系列及病例报告。PABS的发生率为2%，其中94%的病例累及受血双胎。并发PABS的妊娠中，32%存在双胎间隔膜造口术史，90%合并羊膜绒毛膜分离（chorioamniotic separation, CAS）。患者接受FLS时的平均胎龄（gestational age, GA）及分娩时平均胎龄分别为17.7周和30.9周。62%的妊娠发生早产胎膜早破（preterm premature rupture of membranes, PPROM）。胎龄<34周、<32周及<28周的早产（preterm birth, PTB）风险分别为94%、67%和31%。受累胎儿中，41%发生胎儿死亡，64%获得活产。胎儿镜带松解术组与未松解组的结局相当，包括分娩时胎龄、PPROM发生率及32周前早产率。但数据显示，28周前早产率（67% vs 23%）及胎儿死亡率（50% vs 39%）在带松解组中更高。两组的产后截肢率无显著差异。结论：超过三分之一的PABS病例会导致截肢或胎儿死亡。存在双胎间隔膜造口术史、CAS、TTTS晚期分期及早期胎龄的妊娠更易并发PABS。此外，接受FLS治疗的TTTS患者中，超过三分之一会发生早产及PPROM。产前接受带松解术的PABS患者早产及胎儿死亡风险更高，但此类数据均来自样本量较小且异质性较强的研究。