Comparison of Solomon technique with selective laser ablation for twin-twin transfusion syndrome: a systematic review

Stage-based recipient and donor outcome in twin-to-twin transfusion syndrome treated by fetoscopic laser surgery using Solomon technique

OBJECTIVE

To evaluate twin survival stratified by Quintero stage in patients with twin-to-twin transfusion syndrome (TTTS) after Solomon laser treatment.

METHODS

This was a single-center study at Johns Hopkins Center for Fetal Therapy, investigating a cohort of consecutive twin pregnancies treated with the Solomon laser technique for TTTS. Preoperative Quintero stage, perioperative characteristics and obstetric factors were investigated in relation to neonatal survival of the recipient and donor twins at discharge. Determinants of twin survival were evaluated using univariate logistic regression and cumulative survival probability analyses.

RESULTS

Of 402 pregnancies with TTTS that underwent Solomon laser treatment, 80 (19.9%) were diagnosed with Quintero Stage-I TTTS, 126 (31.3%) with Stage II, 169 (42.0%) with Stage III and 27 (6.7%) with Stage IV. Post-laser twin anemia polycythemia sequence or recurrent TTTS occurred in 19 (4.7%) patients and 11 (2.7%) required repeat laser surgery. Preterm prelabor rupture of membranes occurred in 150 (37.3%) patients and median gestational age at delivery was 32 + 1 weeks. In 303 (75.4%) patients, both twins were alive at discharge; 67/80 (83.8%) were Stage I, 101/126 (80.2%) were Stage II, 113/169 (66.9%) were Stage III and 22/27 (81.5%) were Stage IV (P = 0.062). Donor twin survival was lower than that of recipients in cases with Stage-III TTTS (118/169 (69.8%) vs 145/169 (85.8%) (χ2 = 26.076, P < 0.0001)). Higher intertwin size discordance and absent or reversed umbilical artery (UA) end-diastolic velocity (EDV) were associated with donor demise (Nagelkerke R2, 0.38; P < 0.001). Overall, spontaneous post-laser donor demise occurred in 53 (39.6%) patients, accounting for the majority of all losses. Cumulative donor survival decreased from 92% to 65% when intertwin size discordance was >30% and to 48% when UA-EDV was absent or reversed (P < 0.001).

CONCLUSIONS

The Solomon laser technique achieves TTTS resolution and double twin survival in a high proportion of cases. Recipient and donor survival is comparable unless there is significant intertwin size discordance and placental dysfunction. This degree of unequal placental sharing, typically found in Stage-III TTTS, is the primary factor preventing double survival due to a higher rate of donor demise. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.

Placental architectural characteristics following laser ablation within monochorionic twins complicated by twin-twin transfusion syndrome: A systematic review and meta-analysis of outcomes

INTRODUCTION

Twin-twin transfusion syndrome (TTTS) complicates approximately 10%-15% of all monochorionic twin pregnancies. The aim of this review was to evaluate the placental architectural characteristics within TTTS twins following laser and elucidate their impact on fetal outcomes and operative success.

MATERIAL AND METHODS

Five databases were searched from inception to August 2023. Studies detailing post-delivery placental analysis within TTTS twins post-laser were included. Studies were categorized into two main groups: (1) residual anastomoses following laser and (2) abnormal cord insertion: either velamentous and/or marginal or proximate. The primary outcome was to determine the proportion of TTTS placentas with residual anastomoses and abnormal cord insertions post-laser. Secondary outcomes included assessing residual anastomoses on post-laser fetal outcomes and assessing the relationship between abnormal cord insertion and TTTS development. Study bias was critiqued using the Joanna Briggs Institute checklists and Cochrane risk of bias tool. Random-effects meta-analysis was used, and results were reported as pooled proportions or odds ratio (OR) with 95% confidence interval (CI). PROSPERO registration: CRD42023476875.

RESULTS

Twenty-six studies, comprising 4013 monochorionic twins, were included for analysis. The proportion of TTTS placentas with residual anastomoses following laser was 24% (95% CI, 0.12-0.41), with a mean and standard deviation of 4.03 ± 2.95 anastomoses per placenta. Post-laser residual anastomoses were significantly associated with intrauterine fetal death (OR, 2.38 [95% CI, 1.33-4.26]), neonatal death (OR, 3.37 [95% CI, 1.65-6.88]), recurrent TTTS (OR, 24.33 [95% CI, 6.64-89.12]), and twin anemia polycythemia sequence (OR, 13.54 [95% CI, 6.36-28.85]). Combined abnormal cord (velamentous and marginal), velamentous cord, and marginal cord insertions within one or both twins following laser were reported at rates of 49% (95% CI, 0.39-0.59), 27% (95% CI, 0.18-0.38), and 28% (95% CI, 0.21-0.36), respectively. Combined, velamentous and marginal cord insertions were not significantly associated with TTTS twins requiring laser (p = 0.72, p = 0.38, and p = 0.71, respectively) versus non-TTTS monochorionic twins.

CONCLUSIONS

To the best of our knowledge, this is the first review to conjointly explore outcomes of residual anastomoses and abnormal cord insertions within TTTS twins following laser. A large prospective study is necessitated to assess the relationship between abnormal cord insertion and residual anastomoses development post-laser.

Perinatal and neonatal outcomes for fetoscopic laser ablation for the treatment of twin twin transfusion syndrome at a single center

OBJECTIVE

To describe the perinatal and neonatal outcomes of fetal laser ablation (FLA) for the treatment of twin-twin transfusion syndrome (TTTS) in our single center institution.

STUDY DESIGN

Retrospective study of 76 treated pregnant women. Procedural complications, perinatal and neonatal outcomes analyzed. Differences in outcomes between two procedural techniques, selective and Solomon, compared.

RESULTS

FLA occurred at median gestational age (GA) of 20.8 weeks (IQR 18.1-22.9) with low incidence of procedural complications (5.3%). High survival rate with delivery of at least one neonate (96%) [95% CI: 88.9-99.2%]; 73.7% [95% CI: 62.3-83.1%] were twins. Median GA at birth was 33.1 weeks (IQR 28.0-35.0). Neonatal mortality and morbidities were 9.4% and 48.3% of cases respectively, and associated with lower GA. Solomon cases had comparatively higher median GA, and lower incidences of neonatal morbidities.

CONCLUSION

Our small single center study showed favorable outcomes for using the Solomon technique in the treatment of TTTS.

Solomon versus selective fetoscopic laser photocoagulation for twin-twin transfusion syndrome: A systematic review and meta-analysis

This meta-analysis aims to compare the perinatal outcome of twin-twin transfusion syndrome (TTTS) pregnancies undergoing selective versus vascular equator (Solomon) fetoscopic laser photocoagulation (FLP). We performed a systematic search in PubMed and Web of Science from inception up to 25 July 2021. Studies comparing the Solomon and selective techniques of FLP for treatment of TTTS pregnancies were eligible. Random-effects or fixed-effect models were used to pool standardized mean differences (SMD) and log odds ratio. Seven studies with a total of 1664 TTTS pregnancies (n = 671 undergoing Solomon and n = 993 selective techniques) were included. As compared to the selective FLP, Solomon was associated with a lower risk of recurrent TTTS compared to the selective technique (Log odds ratio [OR]: -1.167; 95% credible interval [CrI]: -2.01, -0.33; p = 0.021; I² : 67%). In addition, Solomon was significantly associated with a higher risk of placental abruption than the selective technique (Log [OR]: 1.44; 95% CrI: 0.45, 2.47; p = 0.012; I² : 0.0%). Furthermore, a trend for the higher risk of preterm premature rupture of membranes was observed among those undergoing Solomon (Log [OR]: 0.581; 95% CrI: -0.43, 1.49; p = 0.131; I² : 17%). As compared to selective FLP, the Solomon technique for TTTS pregnancies is associated with a significantly lower recurrence of TTTS; however, it significantly increases the risk of placental abruption.

Solomon technique vs selective fetoscopic laser photocoagulation for twin-twin transfusion syndrome: systematic review and meta-analysis of maternal and perinatal outcomes

OBJECTIVE

To ascertain maternal and perinatal outcomes of monochorionic twin pregnancies complicated by twin-twin transfusion syndrome (TTTS) treated with the Solomon technique compared with selective fetoscopic laser photocoagulation (SFLP) of placental anastomoses.

METHODS

MEDLINE, EMBASE and The Cochrane Library were searched to identify relevant studies. The outcomes observed were perinatal loss and survival, preterm prelabor rupture of membranes (PPROM), preterm birth (PTB), gestational age (GA) at delivery, interval between laser treatment and delivery, maternal bleeding, septostomy or chorioamniotic separation, placental abruption, twin anemia-polycythemia sequence (TAPS), recurrence of TTTS, neonatal morbidity and neurological morbidity. Random-effects head-to-head meta-analyses were used to analyze the data. Pooled odds ratios (OR) and mean differences (MD) and their 95% CIs were calculated.

RESULTS

Nine studies were included in the systematic review. There was generally no difference in the main maternal and pregnancy characteristics between pregnancies treated using the Solomon technique and those treated using SFLP of placental anastomoses. The risks of fetal loss (pooled OR, 0.69 (95% CI, 0.50-0.95); P = 0.023), neonatal death (pooled OR, 0.37 (95% CI, 0.16-0.84); P = 0.018) and perinatal loss (pooled OR, 0.56 (95% CI, 0.38-0.83); P = 0.004) were significantly lower in pregnancies treated using the Solomon technique than in those treated with SFLP. Likewise, pregnancies treated using the Solomon technique had a significantly higher chance of survival of at least one twin (pooled OR, 2.31 (95% CI, 1.03-5.19); P = 0.004) and double survival (pooled OR, 2.18 (95% CI, 1.29-3.70); P = 0.001). There was no difference in the risk of PPROM (P = 0.603), PPROM within 10 days from laser surgery (P = 0.982), PTB (P = 0.207), maternal bleeding (P = 0.219), septostomy or chorioamniotic separation (P = 0.224) or chorioamnionitis (P = 0.135) between the two groups, while the risk of placental abruption was higher in pregnancies treated using the Solomon technique (pooled OR, 2.90 (95% CI, 1.55-5.44); P = 0.001). In the Solomon technique group, pregnancies delivered at a significantly earlier GA than did those treated with SFLP (pooled MD, -0.625 weeks (95% CI, -0.90 to -0.35 weeks); P < 0.001), while there was no difference in the interval between laser treatment and delivery (P = 0.589). The rate of recurrence of TTTS was significantly lower in pregnancies undergoing the Solomon technique (pooled OR, 0.43 (95% CI, 0.22-0.81); P < 0.001), while there was no difference in the risk of TAPS between the two groups (P = 0.792). Finally, there was no difference in the overall risk of neonatal morbidity (P = 0.382) or neurological morbidity (P = 0.247) between the two groups.

CONCLUSIONS

Monochorionic twin pregnancies complicated by TTTS undergoing laser treatment using the Solomon technique had a significantly higher survival rate and lower recurrence rate of TTTS but were associated with an increased risk of placental abruption and earlier GA at delivery compared to those treated with SFLP. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Clinical Value and Treatment Progress of Prenatal Ultrasonography in Twin Pregnancy: A Systematic Review

Assisted reproductive technology has continued to develop in recent years, the technology has become more and more mature, and it has improved the total gestational age of the population. Assisted reproductive technology has improved twin pregnancy rates with the use of ovulation-inducing drugs. The risk factor of twins is much higher than singletons, and adverse pregnancy outcomes such as stillbirth and premature birth are more likely to occur than singletons, especially the special complications of monochorionic twins (MC), and the neonatal mortality and morbidity are also increased. Prenatal diagnosis and prognosis of twin pregnancy, as well as therapeutic interventions, are of current concern. Ultrasound can realize the understanding of intrauterine growth and development of twin pregnancy fetuses during pregnancy, can more accurately determine gestational age, organ function, and maturity, and timely detect fetal growth and development abnormalities in twin pregnancy, while the prognosis and treatment still need further improvement. The purpose of this study was to investigate the clinical value and treatment progress of prenatal ultrasound monitoring in twin pregnancy.

Effect of gestational age at laser therapy on perinatal outcome in monochorionic diamniotic pregnancies affected by twin-to-twin transfusion syndrome

OBJECTIVE

To evaluate the effect of gestational age at laser therapy for twin-to-twin transfusion syndrome (TTTS) on perinatal outcome.

DESIGN AND SETTINGS

Single retrospective observational cohort.

POPULATION

All consecutive pregnancies affected by TTTS and referred to our department between January 2013 and August 2020.

METHODS

Gestational age was modelled both as a categorical and as a continuous variable. Log-binomial regression was used to estimate the odds ratios (crude and adjusted for placental location, Quintero stage and cervical length) as well as the adjusted predicted probability of survival and fetal loss according to gestational age at laser therapy.

MAIN OUTCOMES

Fetal and neonatal survival, preterm prelabour rupture of membranes (PPROM).

RESULTS

Of the 503 pregnancies referred for TTTS, 431 were treated by laser therapy. Gestational age at laser therapy was positively and significantly associated with the overall survival at birth and at discharge (adjusted odds ratio [aOR] 1.12, 95% CI 1.05-1.19), as with a reduction in double fetal loss (aOR 0.81, 95% CI 0.71-0.92). Conversely, the rate of PPROM before 24 weeks was significantly higher in early cases (32% of PPROM <24 weeks when laser therapy was performed before 17 weeks versus 1.5% after 22 weeks, p < 0.001, aOR 0.60, 95% CI 0.48-0.72). Among the survivors, preterm birth before 28 weeks was significantly related to the gestational age at laser (OR 0.91, 95% CI 0.84-0.99), resulting in a significant impact on neonatal morbidity (OR 0.91, 95% CI 0.85-0.97).

CONCLUSION

Our results suggest a significant and independent impact of the gestational age at laser surgery on perinatal survival, PPROM and neonatal morbidity.

Selective vs complete fetoscopic coagulation of vascular equator: a matched comparative study

BACKGROUND

Complete coagulation of the vascular equator (as in the Solomon technique) has been suggested to reduce postoperative complications such as twin anemia polycythemia syndrome and the recurrence of twin-twin transfusion syndrome following fetoscopic laser coagulation of chorionic vessels for twin-twin transfusion syndrome.

OBJECTIVE

We aimed to evaluate the benefit of this technique on perinatal outcomes compared with selective ablation of anastomoses.

STUDY DESIGN

We conducted a monocentric retrospective study comparing selective laser coagulation of anastomoses to the Solomon technique from January 2006 to August 2020. To adjust for potential confounders, the cases operated by selective surgery were matched to the cases operated with the Solomon technique according to the gestational age at laser therapy, placental localization, and Quintero stage using propensity score matching.

RESULTS

With a total of 994 cases, 399 matched pairs were included in the analysis. Compared with selective ablation, the Solomon technique was associated with significantly improved survival: the overall twin survival at delivery and discharge was 72% vs 79% (P=.003) and 69% vs 75% (P=.006), respectively; the double twin survival rate at discharge was 55% vs 65% (P=.02), respectively, and the rate of intrauterine death dropped from 18% to 12% (P=.003), respectively. The Solomon technique significantly reduced the rate of twin anemia polycythemia syndrome (10% vs 4%; P=.02), leading to fewer secondary rescue procedures (13% vs 7.3%; P=.01). However, the Solomon technique was associated with an increased risk of preterm rupture of membranes, especially at early gestational ages (3.8% vs 11%; P<.001 for preterm rupture of membranes <24 weeks). Among the survivors at delivery, both the groups had similar gestational ages at birth. Both neonatal mortality and severe neurologic morbidity were similar in both the groups. However, an increased risk of bronchopulmonary dysplasia was found in the Solomon group (4.5% vs 12%; P<.001).

CONCLUSION

Although the risk of preterm premature rupture of membranes has increased, the introduction of the Solomon technique has significantly improved perinatal outcomes in pregnancies affected with twin-twin transfusion syndrome.

Pathophysiology, diagnosis, and management of twin anemia polycythemia sequence in monochorionic multiple gestations

Twin anemia polycythemia sequence (TAPS) is a consequence of unequal sharing of red blood cells between monochorionic twins resulting in anemia in the donor and polycythemia in the recipient twin. Prenatally TAPS can occur spontaneously or complicate incomplete laser surgery for twin transfusion syndrome. While there may be clinical overlap with twin transfusion syndrome or selective fetal growth restriction, diagnosis relies on Doppler measurement of middle cerebral artery peak systolic velocities. Significantly discordant velocities are diagnostic, while severity staging is based on signs of cardiovascular compromise. Conservative management, fetoscopic laser coagulation, selective twin reduction, fetal blood and exchange transfusion, and delivery may be selected guided by the gestational age of diagnosis, the severity of the condition, the likelihood of success, and the patients' priorities. Prenatal curative treatment that minimizes the risk for prematurity and residual morbidity at birth is most likely to offer the greatest short-term and long-term benefits.

Maternal Fetal Surgery: Intervention and Management

Congenital malformations occur in about 3% of all live births and are a leading cause of perinatal morbidity and mortality. An evolving understanding of the developing human fetus, advances in imaging, availability of cutting-edge instrumentation, and enhanced understanding of fetal pathophysiology, have allowed for prenatal surgical interventions to improve fetal diseases and neonatal outcomes. Fetal surgical therapy is no longer restricted to life-threatening prenatal diagnoses and can be categorized into either open surgical techniques or minimally invasive endoscopic/ultrasound-guided techniques. Patient selection requires a thorough multidisciplinary evaluation and shared decision-making process.

Risk Profiling of the Solomon Technique versus Selective Technique of Fetoscopic Laser Surgery for Twin-Twin Transfusion Syndrome

We evaluated the outcomes and adverse events after fetoscopic laser surgery (FLS) for twin-twin transfusion syndrome (TTTS) using the Solomon technique in comparison to the selective technique. A retrospective analysis of a single-center consecutive cohort of FLS-treated TTTS using the selective (January 2010 to July 2014) and Solomon (August 2014 to December 2017) techniques was performed. Among 395 cases, 227 underwent selective coagulation and 168 underwent the Solomon technique. The incidence rates of recurrent TTTS (Solomon vs. selective: 0% vs. .9%, p = .510) and twin anemia-polycythemia sequence (.6% vs. .4%, p = .670) were very low in both groups. The incidence rates of placental abruption (Solomon vs. selective: 10.7% vs. 3.5%, p = .007) and preterm premature rupture of the membranes (pPROM) with subsequent delivery before 32 weeks (20.2% vs. 7.1%, p < .001) were higher in the Solomon group. The median birth recipient weight was significantly smaller in the Solomon group (1790 g vs. 1933 g, p = .049). The rate of survival of at least one twin was significantly higher in the Solomon group (98.2% vs. 93.8%, p = .046). The Solomon technique and total laser energy were significant risk factors for pPROM (odds ratio: 2.64, 1.07, 95% CI [1.32, 5.28], [1.01, 1.13], p = .006, p = .014, respectively). These findings suggest that the Solomon technique led to superior survival outcomes but increased risks of placental abruption, pPROM and fetal growth impairment. Total laser energy was associated with the occurrence of pPROM. Close attention to adverse events is required for perinatal management after FLS to treat TTTS using the Solomon technique.

Perinatal outcomes and factors affecting the survival rate of fetuses with twin-to-twin transfusion syndrome treated with fetoscopic laser coagulation: a single-center seven-year experience

OBJECTIVES

This single-center study aimed to assess the perinatal outcomes and its associated factors in fetuses with twin-to-twin transfusion syndrome (TTTS) treated by fetoscopic laser coagulation (FLC).

METHODS

In this retrospective study, we included fetuses prenatally diagnosed with TTTS at Asan Medical Center, Seoul, Korea, between October 2011 and December 2018. All patients with TTTS stage II or higher and those with stage I TTTS coupled with symptomatic polyhydramnios or cardiac dysfunction were eligible for FLC.

RESULTS

A total of 172 cases of monochorionic diamniotic twins and one case of dichorionic triamniotic triplets were prenatally diagnosed with TTTS and treated with FLC. The median gestational ages (GAs) at diagnosis and FLC were 20.3 and 20.5 weeks, respectively. The median GA of survivors at delivery was 32.5 weeks. The overall at least one twin- and double-survival rates within 28 days after birth were 82.1% and 55.5%, respectively. The GAs at diagnosis and FLC, Quintero stage, inter-twin weight discordance, associated selective intrauterine growth restriction (sIUGR), procedure time, volume of amnioreduction, preterm prelabor rupture of membranes (PPROM) within one week after FLC, intraoperative intrauterine bleeding, and chorioamnionitis were significant predictive factors of perinatal death. Associated sIUGR, absent end-diastolic flow of umbilical artery, and abnormal cord insertion were significantly associated with donor demise in utero, whereas lower GA at diagnosis and FLC, smaller twins at FLC, pulsatile umbilical vein, and presence of mitral regurgitation were significantly associated with recipient demise in utero. Since the application of the Solomon technique, the survival rate has improved from 75.4% to 88.8%. The FLC before 17 weeks was associated with PPROM within one week after FLC and lower survival rate, whereas that after 24 weeks was associated with twin anemia-polycythemia sequence and higher survival rate. We reached a survival rate of 82% for at least one survival with only 12 procedures.

CONCLUSIONS

FLC is an effective treatment for TTTS. The learning curve reached the acceptable target faster than in previous studies. Several prenatal parameters are identified as predictive factors of fetal survival in TTTS treated with FLC.

Management of Twin Pregnancies: A Comparative Review of National and International Guidelines

Importance

Twin pregnancies are associated with a higher risk of perinatal mortality and morbidity compared with singleton and require more intensive prenatal care.

Objective

The aim of this study was to review and compare the recommendations from published guidelines on twin pregnancies.

Evidence Acquisition

A descriptive review of guidelines from the Royal College of Obstetricians and Gynaecologists, the International Society of Ultrasound in Obstetrics and Gynecology, the Royal Australian and New Zealand College of Obstetricians and Gynaecologists, the National Institute for Health and Care Excellence, the Institute of Obstetricians and Gynaecologists of the Royal College of Physicians of Ireland, the International Federation of Gynecology and Obstetrics, the Society of Obstetricians and Gynaecologists of Canada, and the American College of Obstetricians and Gynecologists on the management of twin pregnancies was conducted.

Results

All the guidelines highlight the importance of an accurate assessment of chorionicity, amnionicity, and gestational age in the first trimester. They also recommend the performance of nuchal translucency and a detailed anomaly scan. The ultrasound surveillance protocol is similar in all guidelines, that is, every 2 weeks for monochorionic and every 4 weeks for dichorionic twins. On the other hand, there are differences regarding the timing and mode of delivery, especially in monochorionic diamniotic twins, in the definition and management of fetal growth discordance, the use of cervical length to screen for preterm birth, and the timing of corticosteroids' administration.

Conclusions

The differences in the reviewed guidelines on the management of twin pregnancies highlight the need for an adoption of an international consensus, in order to improve perinatal outcomes of twin pregnancies.

Neurological complications after therapy for fetal-fetal transfusion syndrome: a systematic review of the outcomes at 24 months

OBJECTIVE

The main objective of this study was to review the available scientific evidence about mid-term neurological outcomes in twins after laser therapy for twin-to-twin transfusion syndrome (TTTS).

METHODS

A systematic review of studies on neurodevelopmental outcomes (cognition, motor development, communication skills and cerebral palsy) of twins after laser therapy for TTTS was conducted. Outcomes at 24 months of age and the use of validated scales for assessment were the selected criteria. Electronic and manual research identified 25 studies, and nine of them were eligible for the review.

RESULTS

The global mean rate of neurological injury in twins treated with laser was 14.07%. The mean rate of cognitive impairment was 8.41%, 11.14% for motor delay, 16.5% for communication delay and 5.73% for cerebral palsy. These rates were higher than the results found in dichorionic twins, but lower than the results found in twins treated with amnio-reductions or conservative management.

CONCLUSION

Laser therapy is associated with a lower rate of neurological injury at 24 months of age compared to other therapeutic techniques. This tendency was also observed with specific incidences regarding cognition, motor skills and cerebral palsy.

Model Surgical Training: Skills Acquisition in Fetoscopic Laser Photocoagulation of Monochorionic Diamniotic Twin Placenta Using Realistic Simulators

Fetoscopic laser coagulation of arterio-venous anastomoses (AVA) in a monochorionic placenta is the standard of care for twin-twin transfusion syndrome (TTTS), but is technically challenging and can lead to significant complications. Acquiring and maintaining the necessary surgical skills require consistent practice, a critical caseload, and time. Training on realistic surgical simulators can potentially shorten this steep learning curve and enables several proceduralists to acquire procedure-specific skills simultaneously. Here we describe realistic simulators designed to allow the user familiarity with the equipment and specific steps required in the surgical treatment of TTTS, including fetoscopic handling, approaches to anterior and posterior placenta, recognition of anastomoses, and efficient coagulation of vessels. We describe the skills that are especially important in conducting placental laser coagulation that the surgeon can practice on the model and apply in a clinical case. These models can be adapted easily depending on the availability of materials and require standard fetoscopy equipment. Such training systems are complementary to traditional surgical apprenticeships and can be useful aids for fetal medicine units that provide this clinical service.

Twin-twin transfusion syndrome - What we have learned from clinical trials

Monochorionic twin pregnancies are at increased risk for adverse outcome compared to dichorionic twin pregnancies and singletons. Monochorionic-specific complications include twin-twin transfusion syndrome (TTTS), twin anemia-polycythemia sequence, single intrauterine fetal demise and its consequences on the co-twin, and selective intrauterine growth restriction. Whereas the natural history of monochorionic-specific complications carries a high risk of fetal death or severe neurologic disability, a framework now exists, based on well-designed clinical trials, for optimal treatment of these entities. Fetoscopic selective laser coagulation of anastomotic vessels on the chorionic plate has been clearly demonstrated to improve survival and neurologic outcomes for Quintero stage ≥2 TTTS. However, many challenges remain unsolved, the most important of which is preterm premature rupture of membranes. Further improvement in the outcomes of monochorionic pregnancies will require improvements in the rate of premature delivery, and improved diagnosis and treatment strategies for early and late onset TTTS.

Fetoscopic laser coagulation in 1020 pregnancies with twin-twin transfusion syndrome demonstrates improvement in double-twin survival rate

OBJECTIVE

To investigate the growing experience and learning curve of fetoscopic laser coagulation of the placental vascular anastomoses in severe mid-trimester twin-twin transfusion syndrome (TTTS) and its influence on perinatal outcome in a single-center setting.

METHODS

Between January 1995 and March 2013 we performed laser therapy in 1020 consecutive pregnancies with TTTS between 15.1 and 27.4 weeks' gestation. We compared perinatal outcome in blocks of five sequential groups of 200 cases, taking into account several covariates in order to adjust for case mix and to demonstrate learning curves and success rates.

RESULTS

The percentage of pregnancies with survival of both fetuses increased from 50.0% (n = 100) in the first 200 cases to 69.5% (n = 153) in the last 220 cases (P = 0.018 for trend) and the overall survival rate for both fetuses in the complete series of 1019 cases with known outcome was 63.3% (n = 645). The survival rate of at least one fetus increased from 80.5% (161/200) in the first group to 91.8% (202/220) in the last group (P = 0.072 for trend) and the overall survival rate of at least one fetus in the complete series was 86.7% (883/1019). In the total population, the mean gestational age at delivery of pregnancies with at least one liveborn neonate was 33.7 ± 3.2 weeks, with a mean interval of 12.9 ± 4.0 weeks between intervention and delivery. Among the first two groups, 124 pregnancies had anterior placentae and were treated with a 0° fetoscope. These cases had the poorest overall outcome, with a double-twin survival rate of 44.4% (55/124), which increased to 65.1% (207/318; P = 0.001) after the introduction of a 30° fetoscope for cases with anterior placenta. The success rate for double-twin survival reached a plateau of 69% at 600 procedures, a rate equalled by a new operator who was trained hands-on and performed 174 of the last 400 procedures.

CONCLUSIONS

We report the largest single-center experience of laser coagulation in TTTS. We observed a continuous increase in double-twin survival rate owing to the growing experience based on the learning curve and refinements in fetoscopic instruments and techniques. These data provide strong arguments for the centralization of minimally invasive intrauterine surgery in specialized high-volume centers. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Trauma induces overexpression of Cx43 in human fetal membrane defects

Objective

We developed an in vitro model to examine whether trauma induces connexin 43 (Cx43) expression and collagen organisation in the amniotic membrane (AM) of fetal membrane (FM) defects.

Method

Term human FM was traumatised in vitro. Cell morphology and Cx43 were examined in the wound edge AM by immunofluorescence (IMF) confocal microscopy and compared to control AM. Collagen microstructure was examined by second harmonic generation (SHG) imaging. Cell viability was assessed with calcein and ethidium staining.

Results

After trauma, the AM showed a dense region of cells, which had migrated towards the wound edge. In wound edge AM, Cx43 puncta was preferentially distributed in mesenchymal cells compared to epithelial cells with significant expression in the fibroblast layer than epithelial layer (p < 0.001). In the fibroblast layer, the collagen fibres were highly polarised and aligned in parallel to the axis of the wound edge AM. There was an absence of cell migration across the defect with no healing after 168 h. Cell viability of the FM after trauma was maintained during culture.

Conclusion

Cx43 overexpression in wounded AM drives structural changes in collagen that slows down efficacy of cell migration across the FM defect. © 2017 The Authors. Prenatal Diagnosis published by John Wiley & Sons, Ltd.

What's already known about this topic?

After fetal surgery, the human fetal membrane shows limited healing and overexpression of Cx43 at the wound edge.

Cx43 knockdown leads to accelerated wound healing by influencing cell migration and tissue dynamics.

What does this study add?

We developed an artificial fetal membrane model to examine Cx43 expression after trauma and changes in collagen dynamics.

We observed Cx43 overexpression and polarised collagen at the wound edge. These changes were found to be similar to human fetoscopic wounds after fetal surgery.

Postnatal survival after endoscopic equatorial laser for the treatment of twin-to-twin transfusion syndrome

BACKGROUND

Endoscopic laser coagulation of placental anastomoses is the first-line treatment for severe twin-to-twin transfusion syndrome. A recent randomized controlled trial reported that laser coagulation along the entire vascular equator was associated with a similar dual survival and survival of at least 1 twin compared with the group that was treated with the selective technique. In addition, there was a significantly lower incidence of postoperative recurrence of twin-to-twin transfusion syndrome and the development of twin anemia-polycythemia sequence in the equatorial group.

OBJECTIVE

The purpose of this study was to report on neonatal survival in twin-to-twin transfusion syndrome pregnancies that were treated with endoscopic laser therapy with the use of the equatorial technique and to examine the relationship between preoperative factors and twin loss.

STUDY DESIGN

Endoscopic equatorial laser therapy was carried out as the primary treatment for twin-to-twin transfusion syndrome in all consecutive monochorionic diamniotic twin pregnancies that were referred at a single fetal surgery Center over a 4-year period. All visible placental anastomoses were coagulated; additional laser ablation of the placental tissue between the coagulated vessels was carried out. Pre-laser ultrasound data, periprocedural complications, pregnancy outcome, and postnatal survival at hospital discharge were recorded and analyzed.

RESULTS

A total of 106 pregnancies were treated during the study period. Median gestational age at laser therapy was 19.7 weeks (range, 15.1-27.6 weeks). There was postoperative recurrence of twin-to-twin transfusion syndrome or the development of twin anemia-polycythemia sequence in 2 (1.9%) and 2 (1.9%) cases, respectively. The survival rates of both and at least 1 twin were 56.6% and 83.0%, respectively. Donor survival was significantly lower compared with the recipient co-twin (64.2% vs 75.5%, respectively; P < .05). The rate of fetal death, which was the most common cause of twin loss, was significantly higher in donors compared with recipient fetuses (23.6% vs 10.4%, respectively; P < .05). In cases with absent or reversed end-diastolic velocity in the donor umbilical artery, dual and donor survival rates were significantly lower compared with the remaining twin-to-twin transfusion syndrome pregnancies (40.0% vs 64.8% and 40.0% vs 76.1%, respectively; P < .05). There were no significant differences between the 2 groups in the survival of at least 1 twin and in the recipient survival.

CONCLUSIONS

Endoscopic equatorial laser therapy was associated with a survival of both and at least 1 twin of approximately 55% and 83%, respectively, with a low rate of recurrent twin-to-twin transfusion syndrome and twin anemia-polycythemia sequence. In addition, the preoperative finding of abnormal donor umbilical artery Doppler on ultrasound identified a subgroup of twin-to-twin transfusion syndrome pregnancies with a lower dual survival rate caused by increased intrauterine deaths of donor twins.