The purpose of this review is to provide an overview of the perinatal outcomes of fetuses who underwent fetal surgery for the management of Amniotic Band Syndrome (ABS). A systematic review of studies reporting on the perinatal outcome of fetuses undergoing fetoscopic release of amniotic bands according to the (PRISMA) guidelines was performed. The MEDLINE, Embase, Scopus, and Cochrane Library databases were systematically searched. In total, 17 studies reporting 37 cases of ABS that underwent amniotic band release by fetoscopy were included. The median gestational age at which fetal surgery was performed was 22 weeks (range 18-29 weeks). PPROM occurred in 51.3%, while fetal survival reached 89.2%. The success of fetal surgery was 75.7% in preserving and maintaining the functionality of the affected limb. Fetoscopic release of amniotic bands can preserve the affected limb and its function in cases of ABS and prevent fetal death in cases of ABS involving the umbilical cord. Further studies are needed to determine the optimal criteria for selecting patients who can benefit from fetal surgery, considering that it is an intervention that is not free of perinatal complications.

Objective: To summarize the clinical value of fetoscopy in the prenatal diagnosis and treatment of amniotic band syndrome (ABS). Methods: A retrospective analysis was conducted on the clinical data of seven ABS fetuses who underwent prenatal fetoscopic intervention at the Third Affiliated Hospital of Zhengzhou University from December 2020 to August 2023. Literatures related to fetoscopic treatment of ABS were searched in databases including China National Knowledge Infrastructure, Wanfang Data, and PubMed. Clinical data were extracted and the characteristics and intervention effects of fetoscopic surgery in the treatment of ABS were summarized. Results: (1) Preoperative evaluation: the gestational age at diagnosis for the seven ABS fetuses was (19.8±4.4) weeks, and the gestational age at fetoscopic intervention was (22.2±2.8) weeks. The indications for fetoscopic intervention included umbilical cord involvement (3 cases), limb amniotic band with circular constriction (2 cases), and unclear visualization of digits (3 cases). (2) Pregnancy outcomes: among the seven ABS fetuses, four cases underwent selective termination of pregnancy due to severe intrauterine limb amputation, and three cases underwent fetoscopic lysis of amniotic bands. Among the latter three cases, one case experienced intrauterine fetal death (IUFD) two weeks after the procedure, and two cases had good postoperative outcomes. (3) Literature review: a total of 40 cases, including 37 cases from 17 articles and three cases from our institution, were included in the analysis. The indications for fetoscopic surgery included limb amniotic band with circular constriction and involvement of the umbilical cord. The success rate of the surgery was 82% (33/40), and 78% (29/37) of the affected limbs retained good functionality. Premature rupture of membranes was the most common complication, with an incidence rate of 48% (16/33). The average interval from the surgery to membrane rupture was (6.1±5.1) weeks, and the average interval from the surgery to delivery was (10.5±4.1) weeks, with an average gestational age at delivery of (33.7±3.6) weeks. The pregnant women were divided into single Trocar group (27 cases) and double Trocar group (13 cases) based on the surgical approach. The success rates in single Trocar group and double Trocar group were 78% (21/27) and 12/13, respectively, and the difference was not statistically significant (χ2=0.474, P=0.491). The gestational age of delivery in the single Trocar group and double Trocar group was (32.7±3.4) and (35.4±3.2) weeks, respectively, and the difference was statistically significant (t=-2.185, P<0.05). There were no statistically significant differences in the success rate of the surgery, incidence of premature rupture of membranes, interval between surgery and membrane rupture, interval between surgery and delivery, and preterm delivery rate between the two groups (all P>0.05). Conclusions: Fetoscopy could be used for prenatal assessment and intrauterine treatment of ABS. Fetoscopic lysis of amniotic bands may be an effective method for treating ABS, which helps preserve limb function and prevent intrauterine limb amputation and IUFD.
目的： 探讨胎儿镜在羊膜带综合征（ABS）宫内诊断和治疗中的临床应用价值。 方法： 回顾性分析2020年12月至2023年8月于郑州大学第三附属医院行宫内胎儿镜干预的7例ABS胎儿的临床资料。在中国知网、万方、PubMed数据库检索胎儿镜治疗ABS的文献，提取临床资料，总结胎儿镜手术治疗ABS的特点和干预效果。 结果： （1）胎儿镜干预前评估：7例ABS胎儿的诊断孕周为（19.8±4.4）周，干预孕周为（22.2±2.8）周，胎儿镜干预指征包括：脐带受累（3例），肢体羊膜带出现缩窄环（2例），指端显示不清（3例）。（2）妊娠结局：7例ABS胎儿中，4例因胎儿镜检查发现严重宫内截肢或截指选择优生引产；3例行胎儿镜羊膜带松解术，其中1例术后2周发生胎儿宫内死亡（IUFD），2例预后良好。（3）文献复习结果：纳入文献17篇（共37例ABS胎儿），加上本院实施胎儿镜手术治疗的3例，共纳入40例胎儿镜羊膜带松解术，手术指征包括肢体羊膜带伴缩窄环形成、脐带受累，手术成功率82%（33/40），33例手术成功胎儿累及的37例次肢体受累中，78%（29/37）的受累肢体保留了良好的功能。33例手术成功胎儿中，胎膜早破是最主要的并发症，发生率为48%（16/33），手术至胎膜早破的时间间隔为（6.1±5.1）周，手术至分娩的时间间隔（10.5±4.1）周，分娩孕周为（33.7±3.6）周；按手术路径使用穿刺套管（Trocar）数目，分为单Trocar组（27例）与双Trocar组（13例），成功率分别为78%（21/27）、12/13，两组比较，差异无统计学意义（χ2=0.474，P=0.491）；手术成功者的分娩孕周分别为（32.7±3.4）、（35.4±3.2）周，两组比较，差异有统计学意义（t=-2.185，P<0.05），两组的手术成功率、胎膜早破发生率、手术至胎膜早破时间间隔、手术至分娩时间间隔、早产率分别比较，差异均无统计学意义（P均>0.05）。 结论： 胎儿镜可用于ABS的宫内诊断和治疗，胎儿镜羊膜带松解术可能是治疗ABS的有效方法，有助于保留肢体功能、防止宫内截肢和IUFD的发生。.

Background: We aimed to conduct a systematic review and meta-analysis to evaluate the fetoscopic tracheal occlusion in patients with isolated severe and left-sided diaphragmatic hernia. Methods: Cochrane Library, Embase, and PubMed (Medline) databases were searched from inception to February 2024 with no filters or language restrictions. We included studies evaluating the outcomes of fetoscopic intervention compared to expectant management among patients with severe congenital diaphragmatic hernia exclusively on the left side. A random-effects pairwise meta-analysis was performed using RStudio version 4.3.1. Results: In this study, we included 540 patients from three randomized trials and five cohorts. We found an increased likelihood of neonatal survival associated with fetoscopic tracheal occlusion (Odds Ratio, 5.07; 95% Confidence Intervals, 1.91 to 13.44; p < 0.01) across general and subgroup analyses. Nevertheless, there were higher rates of preterm birth (OR, 5.62; 95% CI, 3.47-9.11; p < 0.01) and preterm premature rupture of membranes (OR, 7.13; 95% CI, 3.76-13.54; p < 0.01) in fetal endoscopic tracheal occlusion group compared to the expectant management. Conclusions: Our systematic review and meta-analysis demonstrated the benefit of fetoscopic tracheal occlusion in improving neonatal and six-month postnatal survival in fetuses with severe left-sided CDH. Further studies are still necessary to evaluate the efficacy of tracheal occlusion for isolated right-sided CDH, as well as the optimal timing to perform the intervention.

BACKGROUND: We aimed to investigate the incidence, prenatal factors and outcomes of twin-to-twin transfusion (TTTS) with right ventricular outflow tract obstruction (RVOTO).
METHODS: A systematic search was conducted to identify relevant studies published until February 2023 in English using the databases PubMed, Scopus and Web of Science. Studies reporting on pregnancies with TTTS and RVOTO were included. The random-effect model pooled the mean differences or odds ratios (OR) and the corresponding 95% confidence intervals. Heterogeneity was assessed using the I2 value.
RESULTS: A total of 17 studies encompassing 4332 TTTS pregnancies, of which 225 cases had RVOTO, were included. Incidence of RVOTO at time of TTTS diagnosis was 6%. In all, 134/197 (68%) had functional pulmonary stenosis and 62/197 (32%) had functional pulmonary atresia. Of these, 27% resolved following laser and 55% persisted after birth. Of those persisting, 27% required cardiac valve procedures. Prenatal associations were TTTS stage III (53% vs 39% in no-RVOTO), stage IV TTTS (28% in RVOTO vs 12% in no-RVOTO) and ductus venosus reversed a-wave (60% in RVOTO vs 19% in no-RVOTO). Gestational age at laser and gestational age at delivery were comparable between groups. Survival outcomes were also comparable between groups, including fetal demise of 26%, neonatal death of 12% and 6-month survival of 82% in RVOTO group. Findings were similar when subgroup analysis was done for studies including head-to-head analysis.
CONCLUSIONS: RVOT occurs in about 6% of the recipient twins with TTTS, especially in stages III and IV and those with reversed ductus venosus a-wave. The findings from this systematic review support the need for a thorough cardiac assessment of pregnancies complicated by TTTS, both before and after laser, to maximize perinatal outcome, and the importance of early diagnosis of TTTS and timely management.

Pulmonary hypoplasia is one of main causes of neonatal mortality and morbidity in patients with congenital diaphragmatic hernia. With most cases diagnosed prenatally, the emphasis is put on prediction of the severity of this defect. Several attempts are made to reduce the mortality and provide optimal prenatal and postnatal care. Appropriate estimation of risk of pulmonary hypoplasia also provides an important inclusion criterion for prenatal intervention. The main tool used for the detection and prediction of pulmonary hypoplasia is ultrasound, with an increasing number of available formulas to estimate the risk of occurrence of this phenomenon and complication associated with it. For most of the formulas used in this measurement method, the main limitations are either gestational-age dependency or limited research. Other imaging methods used to assess the risk of pulmonary hypoplasia involve magnetic resonance imaging and vascular assessment of affected lungs. The limitation in these remains the limited accessibility. Currently, the most widely used indexes are observed-to-expected lungs-to-head ratio and presence of liver herniation. These are the 2 most commonly used measurement methods, as they are the basis for patient qualification for fetoscopic endoluminal tracheal occlusion. This article aims to review the evaluation of pulmonary hypoplasia or hypoplastic lung disease as an important determinant of clinical outcomes in infants with congenital diaphragmatic hernia. In this review, we emphasize the importance of early prenatal diagnosis of congenital diaphragmatic hernia and present a summary of different methods of prenatal risk assessment of lung hypoplasia in congenital diaphragmatic hernia.

BACKGROUND: Our objective was to investigate outcomes in twin-to-twin transfusion syndrome (TTTS) treated with fetoscopic laser surgery (FLS) at <18 weeks vs ≥18 weeks, and to conduct subgroup analysis of TTTS with FLS at <16 weeks vs 16-18 weeks.
METHODS: PubMed, Scopus and Web of Science were searched systematically from inception until May 2023. Primary outcome was survival, and secondary outcomes included preterm premature rupture of membranes (PPROM), preterm birth and gestational age (GA) at delivery.
RESULTS: Nine studies encompassing 1691 TTTS pregnancies were included. TTTS stage III was significantly more common in TTTS pregnancies treated with FLS at <18 weeks (odds ratio [OR] 2.84, 95% confidence interval [CI] 1.24-6.54), and procedure duration was shorter at <18 weeks (MD -5.27 minutes, 95% CI -9.19 to -1.34). GA at delivery was significantly earlier in TTTS pregnancies treated with FLS at <18 weeks (MD -3.12 weeks, 95% CI -6.11 to -0.13). There were no significant differences in outcomes, including PPROM, PPROM at <7 days post-FLS, preterm birth at <28 and <32 weeks, delivery at <7 days post-FLS, and survival outcomes, including fetal demise, live birth and neonatal survival. Similarly, TTTS stage III was more common in TTTS with FLS at <16 weeks than at 16-18 weeks (OR 2.95, 95% CI 1.62-5.35), with no significant differences in the aforementioned outcomes.
CONCLUSIONS: In early TTTS treated with FLS, outcomes were comparable between those treated at <18 weeks compared with ≥18 weeks except for GA at delivery, which was 3 weeks earlier. In the subset treated at <16 weeks vs 16-18 weeks, the procedure was feasible without an increased risk of very early preterm birth or perinatal mortality.

BACKGROUND: Preterm prelabor rupture of membranes (PPROM) remains a major complication of fetal laser surgery in the treatment of twin-to-twin transfusion syndrome (TTTS). The aim of the study was to determine the impact of cannula size on pregnancy outcomes, with a particular focus on PPROM.
METHODS: The protocol was developed and registered in the PROSPERO database under registration number CRD42022333630. The PubMed, Web of Science, and EMBASE databases were searched electronically on May 18, 2022, and updated on March 2, 2023, utilizing a combination of the relevant MeSH terms, keywords, and word variants for \"TTTS\" and \"laser\". Randomized controlled trials, prospective and retrospective cohorts, case-control studies, and case reports/series with more than five participants were considered eligible for inclusion. Studies reporting the cannula diameter and PPROM rate after laser surgery in the treatment of monochorionic pregnancies affected by TTTS between 16- and 26 weeks\' gestation were included. Data was extracted independently, and when appropriate, a random-effects meta-analysis was undertaken to calculate pooled estimates and their confidence intervals. Heterogeneity in the effect estimates of the individual studies was calculated using the I2 statistic. The primary outcome was PPROM rate. Secondary outcomes were survival rate, preterm birth, and incomplete surgery. The quality of the included studies was assessed using a modified quality in prognosis study tool.
RESULTS: We included a total of 22 studies, consisting of 3426 patients. Only one study was scored as low quality, seven as moderate quality, and the remaining 14 as high quality. The mean PPROM rate after laser surgery treating TTTS was 22.9%, ranging from 11.6% for 9 French (Fr) to 54.0% for 12 Fr. Subsequent meta-regression for the clinically relevant PPROM rate before 34 weeks of gestation, showed increased PPROM rates for increased cannula size (p-value 0.01).
CONCLUSIONS: This systematic review confirmed PPROM as a frequent complication of fetal laser surgery, with a mean PPROM rate of 22.9%. A larger cannula diameter relates to a significant higher PPROM risk for PPROM before 34 weeks gestation. Hence, the ideal balance between optimal visualization requiring larger port diameters and shorter operation time and more complete procedures that benefit from larger diameters is crucial to reduce iatrogenic PPROM rates.

Fetoscopy laser photocoagulation is a widely adopted procedure for treating Twin-to-Twin Transfusion Syndrome (TTTS). The procedure involves photocoagulation pathological anastomoses to restore a physiological blood exchange among twins. The procedure is particularly challenging, from the surgeon\'s side, due to the limited field of view, poor manoeuvrability of the fetoscope, poor visibility due to amniotic fluid turbidity, and variability in illumination. These challenges may lead to increased surgery time and incomplete ablation of pathological anastomoses, resulting in persistent TTTS. Computer-assisted intervention (CAI) can provide TTTS surgeons with decision support and context awareness by identifying key structures in the scene and expanding the fetoscopic field of view through video mosaicking. Research in this domain has been hampered by the lack of high-quality data to design, develop and test CAI algorithms. Through the Fetoscopic Placental Vessel Segmentation and Registration (FetReg2021) challenge, which was organized as part of the MICCAI2021 Endoscopic Vision (EndoVis) challenge, we released the first large-scale multi-center TTTS dataset for the development of generalized and robust semantic segmentation and video mosaicking algorithms with a focus on creating drift-free mosaics from long duration fetoscopy videos. For this challenge, we released a dataset of 2060 images, pixel-annotated for vessels, tool, fetus and background classes, from 18 in-vivo TTTS fetoscopy procedures and 18 short video clips of an average length of 411 frames for developing placental scene segmentation and frame registration for mosaicking techniques. Seven teams participated in this challenge and their model performance was assessed on an unseen test dataset of 658 pixel-annotated images from 6 fetoscopic procedures and 6 short clips. For the segmentation task, overall baseline performed was the top performing (aggregated mIoU of 0.6763) and was the best on the vessel class (mIoU of 0.5817) while team RREB was the best on the tool (mIoU of 0.6335) and fetus (mIoU of 0.5178) classes. For the registration task, overall the baseline performed better than team SANO with an overall mean 5-frame SSIM of 0.9348. Qualitatively, it was observed that team SANO performed better in planar scenarios, while baseline was better in non-planner scenarios. The detailed analysis showed that no single team outperformed on all 6 test fetoscopic videos. The challenge provided an opportunity to create generalized solutions for fetoscopic scene understanding and mosaicking. In this paper, we present the findings of the FetReg2021 challenge, alongside reporting a detailed literature review for CAI in TTTS fetoscopy. Through this challenge, its analysis and the release of multi-center fetoscopic data, we provide a benchmark for future research in this field.

BACKGROUND: Pseudoamniotic band sequence (PABS) is a rare iatrogenic consequence of invasive fetal interventions, most commonly fetoscopic laser surgery (FLS) in monochorionic multiple pregnancies complicated by twin-to-twin transfusion syndrome (TTTS).
OBJECTIVE: The aim of this study was to investigate prenatal risk factors and perinatal outcomes for pregnancies involving PABS after FLS for TTTS and compare outcomes between those undergoing fetoscopic band release versus 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.
CONCLUSIONS: 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.

To investigate the outcomes of asymptomatic stage I twin-to-twin transfusion syndrome (stage I TTTS) among patients treated with fetoscopic laser photocoagulation (FLP) versus expectant management. Databases such as PubMed, Web of Science and Scopus were systematically searched from inception up to March 1st, 2022. The primary outcome was at least one fetal survival at birth and secondary outcomes included gestational age at delivery, preterm premature rupture of membranes < 32 weeks, preterm birth < 32 weeks, and single and dual fetal survival. Five studies were included in the meta-analysis. There was no significant difference in terms of at least one survival (odds ratio (OR) = 1.40, 95%CI= (0.26, 7.43), P = 0.70), single survival (OR = 0.87, 95%CI= (0.51, 1.48), P = 0.60) and dual survival (OR = 1.63, 95%CI= (0.74, 3.62), P = 0.23) among FLP and expectant groups. Gestational age at delivery (mean difference = 1.19, 95%CI= (-0.25, 2.63), P = 0.10), the risk of PTB<32 weeks (OR = 0.88, 95%CI= (0.50, 1.54), P = 0.65), and pPROM<32 weeks (OR = 1.80, 95% CI= (0.41, 7.98), P = 0.44) were also comparable between the groups. Routine FLP of the placental anastomoses before 26 weeks of gestation is unlikely to be beneficial among asymptomatic stable stage I TTTS patients without cervical shortening as the procedure does not offer a survival advantage compared with expectant management.