Trocar-assisted selective laser photocoagulation of communicating vessels: A technique for the laser treatment of patients with twin–twin transfusion syndrome with inaccessible anterior placentas

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.

Third-trimester fetoscopic ablation therapy for types II and III vasa previa

BACKGROUND

Vasa previa is an obstetrical condition in which fetal vessels located near the cervix traverse the fetal membranes unprotected by underlying placenta. Type I vasa previa arises directly from a velamentous cord root, whereas types II and III arise from an accessory lobe or a distal lobe of the same placenta, respectively. Fetoscopic laser ablation for types II and III vasa previa is a novel therapeutic option with benefits that include surgical resolution of the vasa previa, avoidance of prolonged hospitalization, and opportunity for a term vaginal delivery. The potential risks of fetoscopy can be mitigated by delaying laser surgery until a gestational age of 31 to 33 weeks, immediately before anticipated hospitalized surveillance.

OBJECTIVE

This study aimed to assess feasibility and outcomes of types II and III vasa previa patients treated via fetoscopic laser ablation in the third trimester.

STUDY DESIGN

This is a retrospective study of singleton pregnancies with types II and III vasa previa treated with fetoscopic laser ablation at a gestational age ≥31 weeks at a single center between 2006 and 2022. Pregnancy and newborn outcomes were assessed. Continuous variables are expressed as mean±standard deviation.

RESULTS

Of 84 patients referred for vasa previa, 57 did not undergo laser ablation: 19 either had no or resolved vasa previa, 25 had type I vasa previa (laser-contraindicated), and 13 had type II or III vasa previa but declined laser treatment. Of the remaining 27 patients who underwent laser ablation, 7 were excluded (laser performed at <31 weeks and/or twins), leaving 20 study patients. The mean gestational age at fetoscopic laser ablation was 32.0±0.6 weeks, and total operative time was 62.1±19.6 minutes. There were no perioperative complications. All patients had successful occlusion of the vasa previa vessels (1 required a second procedure). All patients were subsequently managed as outpatients. The mean gestational age at delivery was 37.2±1.8 weeks, the mean birthweight was 2795±465 g, and 70% delivered vaginally. Neonatal intensive care unit admission occurred in 3 cases: 1 for respiratory distress syndrome and 2 for hyperbilirubinemia requiring phototherapy. There were no cases of neonatal transfusion, intraventricular hemorrhage, sepsis, patent ductus arteriosus, or death.

CONCLUSION

Laser ablation for types II and III vasa previa at 31 to 33 gestational weeks was technically achievable and resulted in favorable outcomes.

Subclassification of fetal growth restriction type IIa vs type IIb applied to twin-twin transfusion syndrome

BACKGROUND

Subclassification of monochorionic twins with selective fetal growth restriction type II into IIa vs IIb has been proposed because of differing neonatal survival outcomes of the fetus with growth restriction after laser surgery based on preoperative Doppler findings in the middle cerebral artery and ductus venosus. There is substantial clinical overlap between selective fetal growth restriction and twin-twin transfusion syndrome.

OBJECTIVE

This study aimed to compare donor twin neonatal survival after laser surgery in cases of twin-twin transfusion syndrome with concomitant donor fetal growth restriction type IIa vs IIb.

STUDY DESIGN

This was a retrospective study of monochorionic multifetal pregnancies treated with laser surgery for stage III twin-twin transfusion syndrome and concomitant donor twin fetal growth restriction type II at a referral center from 2006 to 2021. Donor fetal growth restriction type II was defined as having an estimated fetal weight <10th percentile with persistent absent and/or reversed end-diastolic velocity in the umbilical artery. Moreover, patients were subclassified as type IIa (having normal middle cerebral artery peak systolic velocities and ductus venosus Doppler waveforms) vs type IIb (having middle cerebral artery peak systolic velocities ≥1.5 multiples of the median and/or ductus venosus with persistent absent or reversed atrial systolic flow). This study compared 30-day neonatal survival of the donor twin by fetal growth restriction type IIa vs IIb using logistic regression to adjust for relevant preoperative covariates (P<.10 in bivariate analysis).

RESULTS

Of 919 patients who underwent laser surgery for twin-twin transfusion syndrome, 262 had sstage III donor or donor and recipient twin-twin transfusion syndrome; of these patients, 189 (20.6%) had concomitant donor fetal growth restriction type II. Moreover, 12 patients met the exclusion criteria, yielding 177 patients (19.3%) who composed the study cohort. Patients were subclassified as donor fetal growth restriction type IIa (146 [82%]) vs type IIb (31 [18%]). Donor neonatal survival for fetal growth restriction type IIa vs IIb was 71.2% vs 41.9% (P=.003). Recipient neonatal survival did not differ between the 2 types (P=1.000). Patients classified with twin-twin transfusion syndrome and concomitant donor fetal growth restriction type IIb were 66% less likely to have neonatal survival of the donor after laser surgery (adjusted odds ratio, 0.34; 95% confidence interval, 0.15-0.80; P=.0127). The logistic regression model was adjusted for gestational age at the procedure, estimated fetal weight percent discordance, and nulliparity. The c-statistic was 0.702.

CONCLUSION

For patients with stage III twin-twin transfusion syndrome and concurrent donor fetal growth restriction with persistent absent or reversed end-diastolic velocity in the umbilical artery (ie, fetal growth restriction type II), subclassification into fetal growth restriction type IIb based on elevated middle cerebral artery peak systolic velocity and/or abnormal ductus venosus flow in the donor conveyed poorer prognosis. Although donor neonatal survival after laser surgery was lower for patients with stage III twin-twin transfusion syndrome with donor fetal growth restriction type IIb than patients with stage III twin-twin transfusion syndrome with donor fetal growth restriction with type IIa, laser surgery for fetal growth restriction type IIb in the setting of twin-twin transfusion syndrome (as opposed to pure selective fetal growth restriction type IIb) still allows for the possibility of dual survivorship and should be offered with shared decision-making when counseling patients on management options.

Single fetal demise following fetoscopic ablation for twin-to-twin transfusion syndrome-cohort study, systematic review, and meta-analysis

BACKGROUND

Several studies have assessed preoperative and operative factors associated with fetal demise after laser for TTTS, yet these findings are not completely conclusive.

OBJECTIVE

This study aimed to identify risk factors for single fetal demise (recipient and donor twins) after fetoscopic laser photocoagulation for twin-to-twin transfusion syndrome.

STUDY DESIGN

We searched PubMed, Scopus, and Web of Science systematically from the inception of the database to June 2020. We conducted a systemic review on studies investigating risk factors for fetal demise (donor and/or recipient) after fetoscopic laser photocoagulation in monochorionic pregnancies complicated with twin-to-twin transfusion syndrome. Initially, we investigated the cohort of women with twin-to-twin transfusion syndrome that underwent fetoscopic laser photocoagulation at our 2 high-volume fetal centers between 2012 and 2020 to identify risk factors for donor demise and recipient demise. Furthermore, we conducted a systematic review of the literature to better characterize these factors. Among studies that met the entry criteria, multiple preoperative and operative factors were tabulated. The random-effect model was used to pool the standardized mean differences or odds ratios and corresponding 95% confidence intervals. Heterogeneity was assessed using the I² value.

RESULTS

A total of 514 pregnancies with twin-to-twin transfusion syndrome managed with fetoscopic laser photocoagulation were included in the final analysis. Following the logistic regression, factors that remained significant for donor demise were selective fetal growth restriction (odds ratio, 1.9; 95% confidence interval, 1.3-2.8; P=.001) and umbilical artery blood flow with absent or reversed end-diastolic velocity of the donor (odds ratio, 2.06; 95% confidence interval, 1.2-3.4; P=.004). A significant factor associated with recipient demise was absent or reversed a-wave in the ductus venosus of the recipient (odds ratio, 1.74; 95% confidence interval, 1.07-3.13; P=.04). Data from 23 studies and our current cohort were included. A total of 4892 pregnancies with twin-to-twin transfusion syndrome managed with fetoscopic laser photocoagulation were analyzed for risk factors for donor demise, and 4594 pregnancies with twin-to-twin transfusion syndrome were analyzed for recipient demise. Among studies, the overall incidence rates ranged from 10.9% to 35.8% for donor demise and 7.3% to 24.5% for recipient demise. Significant risk factors for donor demise were intertwin estimated fetal weight discordance of >25% (odds ratio, 1.86; 95% confidence interval, 1.44-2.4; I², 0.0%), selective fetal growth restriction (odds ratio, 1.78; 95% confidence interval, 1.4-2.27; I², 0.0%), twin-to-twin transfusion syndrome stage III (odds ratio, 2.18; 95% confidence interval, 1.53-3.12; I², 0.0%), umbilical artery blood flow with absent or reversed end-diastolic velocity of the donor (odds ratio, 2.31; 95% confidence interval, 1.9-2.8; I², 23.7%), absent or reversed a-wave in the ductus venosus of the donor (odds ratio, 1.83; 95% confidence interval, 1.45-2.3; I², 0.0%), and presence of arterioarterial anastomoses (odds ratio, 2.81; 95% confidence interval, 1.35-5.85; I², 90.7%). Sequential selective coagulation was protective against donor demise (odds ratio, 0.31; 95% confidence interval, 0.16-0.58; I², 0.0%). Significant risk factors for recipient demise were twin-to-twin transfusion syndrome stage IV (odds ratio, 2.18; 95% confidence interval, 1.01-4.6; I², 16.5%), umbilical artery blood flow with absent or reversed end-diastolic velocity of the recipient (odds ratio, 2.68; 95% confidence interval, 1.91-3.74; I², 0.0%), absent or reversed a-wave in the ductus venosus of the recipient (odds ratio, 2.37; 95% confidence interval, 1.55-3.64; I², 60.2%), and middle cerebral artery peak systolic velocity of >1.5 multiple of the median (odds ratio, 3.06; 95% confidence interval, 1.36-6.88; I², 0.0%).

CONCLUSION

Abnormal blood flow patterns represented by abnormal Doppler studies and low fetal weight were associated with single fetal demise in women with twin-to-twin transfusion syndrome undergoing laser therapy. Although sequential selective coagulation was protective against donor demise, the presence of arterioarterial anastomoses was considerably associated with donor demise. This meta-analysis extensively investigated the association of a wide range of preoperative and operative factors with fetal demise. These findings may be important inpatient counseling, in further understanding the disease, and perhaps in improving surgical techniques.

Twin-to-twin transfusion syndrome: Controversies in the diagnosis and management

In twin-to-twin transfusion syndrome (TTTS) communicating placental vessels on the chorionic plate between the donor and recipient twins are responsible for the chronic imbalance of blood flow. Evidence demonstrates that fetoscopic laser ablation is superior to serial amnioreductions in terms of survival and neurological outcome for stages II-IV TTTS. However, the optimal management of stage I TTTS remains poorly understood. It is well established that all chorionic plate anastomoses should be closed by laser ablation. Compared to the selective laser method, the Solomon technique yields a significant reduction of recurrent TTTS and post-laser twin anemia polycythemia sequence (TAPS). Over the past 25 years, survival rates after fetoscopic laser surgery have significantly increased. High volume centers report up to 70% double survival and at least one survivor in >90% cases. In this review, we discuss the controversies in the diagnosis and management of TTTS, especially, the optimal management in stage I cases, very early or late diagnosis, and the optimal laser technique. Furthermore, we will discuss a stage-related outcome after laser surgery and examine whether it is necessary at all to distinguish between stages I and II. Finally, the optimal timing as well as mode of delivery after TTTS laser treatment will be discussed.

Outcomes of laser surgery for stage I twin-twin transfusion syndrome

OBJECTIVE

A recent randomized controlled trial (RCT) demonstrated no difference in 6 month survival in expectantly managed stage I twin-twin transfusion syndrome (TTTS) patients and those undergoing immediate laser surgery. We aimed to describe outcomes following immediate laser surgery at a single fetal surgery center.

METHODS

A retrospective study of monochorionic diamniotic twins diagnosed with stage I TTTS who underwent laser surgery between 16 and 26 gestational weeks from 2006 to 2019. The primary outcome was 6 month survivorship. Intact survival was also assessed. Secondarily, outcomes were compared to the RCT expectant management group.

RESULTS

Of 126 consecutive stage I TTTS patients, 114 (90.5%) met inclusion criteria. Median (range) gestational age at delivery was 34.1 (20.6-39.4) weeks. At 6 months, the proportion of patients with at-least-one survivor in the single-center-laser cohort was 97.4%, with 88.6% dual survivorship. Neurological morbidity outcomes were available in 110 pregnancies (220 fetuses). Severe neurological morbidity occurred in 2.7% (6/220), and 6 month survival without severe neurological morbidity was 90.0%. Outcomes compared favorably with the RCT expectant management group.

CONCLUSIONS

Given favorable survival and neurological outcomes, laser surgery is a reasonable treatment option for stage I TTTS at experienced fetal surgery centers. Further study is warranted to optimize treatment strategies.

Outcomes of laparoscopy-assisted fetoscopic laser photocoagulation for twin-twin transfusion syndrome: An established alternative for inaccessible anterior placenta

OBJECTIVE

To evaluate laparoscopy-assisted fetoscopic laser photocoagulation (FLPC) of placental anastomoses in the treatment of twin-to-twin-transfusion syndrome (TTTS).

STUDY DESIGN

We performed a retrospective cohort study analyzing pregnancies complicated by TTTS who underwent FLPC in a single university-affiliated tertiary medical-center. Outcomes were compared between patients who received laparoscopy-assisted FLPC (study group) and patients who underwent the conventional FLPC technique (control group). Baseline characteristics, sonographic findings, procedure details, and neonatal outcomes were compared between groups.

RESULTS

The cohort included 278 women with 31 in the study group and 247 in the control group. Sonographic parameters, including fetal biometry and TTTS stage, were comparable between study groups. Gestational age at delivery did not differ between the groups (29.22 ± 4.55 weeks in the study group vs. 30.62 ± 4.3 weeks in the control group, p = 0.09). There were no differences in neonatal survival rates at birth and at 30 days between both groups. A subanalysis comparing the laparoscopy-assisted group to only those patients with anterior placenta in the control group, showed a lower rate of incomplete Solomonization in the laparoscopy-assisted study group (3.4% vs. 33%, p = 0.01).

CONCLUSION

Laparoscopy-assisted FLPC is a reasonable and safe option that may be offered in cases of FLPC where an anterior placenta restricts adequate surgical access.

Early laser surgery is not associated with very preterm delivery or reduced neonatal survival in TTTS

OBJECTIVE

To evaluate the association of laser photocoagulation of placental anastomoses (LPA) prior to 18 weeks' gestation (early LPA) with very preterm delivery and neonatal survival in pregnancies with twin-twin transfusion syndrome (TTTS).

METHODS

This was a retrospective cohort study of monochorionic diamniotic twin pregnancies with TTTS undergoing LPA between 2002 and 2018 at two institutions. The rates of delivery < 28, < 30 and < 32 weeks' gestation, preterm prelabor rupture of membranes (PPROM) and 30-day survival of one or both infants were compared between pregnancies undergoing early LPA and those undergoing LPA ≥ 18 weeks' gestation. Regression analysis was performed to determine the association of early LPA with very preterm delivery and 30-day survival, adjusted for Quintero stage, study phase, selective fetal growth restriction, gestational age at delivery, maternal age ≥ 35 years, body mass index > 35 kg/m² , placental location, use of Seldinger method to place the operative trocar, size of the trocar, participating center, use of Solomon technique, cerclage and PPROM. Survival analysis using the Cox proportional hazard model was applied to examine the LPA-to-delivery interval according to the timing of surgery, adjusted for confounding variables.

RESULTS

A total of 414 TTTS pregnancies were included in the study, of which 68 (16.4%) underwent early LPA. In the total cohort, the incidence of delivery at < 28, < 30 and < 32 weeks' gestation was 22.7%, 39.6% and 53.4%, respectively. Survival of both twins and survival of at least one twin at 30 days were 67.5% and 90.8%, respectively. No significant difference was noted between pregnancies that underwent early LPA and those that had LPA ≥ 18 weeks in the rate of delivery < 28 weeks (19.1% vs 23.4%; P = 0.4), < 30 weeks (38.2% vs 39.9%; P = 0.8) and < 32 weeks (44.1% vs 55.2%; P = 0.1) and PPROM (29.0% vs 24.1%; P = 0.4), or in the incidence of double-twin survival (63.9% vs 68.1%; P = 0.5) and survival of at least one infant (91.8% vs 90.6%; P = 0.7) at 30 days. Early LPA was not associated with very preterm delivery or neonatal survival in the regression analyses. Early LPA was associated with a longer LPA-to-delivery interval compared with LPA performed ≥ 18 weeks (median, 106.9 days (range, 2-164 days) vs median, 69.3 days (range, 0-146 days); P < 0.001) when adjusted for confounding variables (hazard ratio, 2.56 (95% CI, 1.76-3.73); P < 0.001).

CONCLUSION

Laser surgery before 18 weeks is not associated with an increased rate of very preterm delivery and PPROM or with reduced neonatal survival when compared with LPA after 18 weeks. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Selective intrauterine growth restriction (SIUGR) type II: proposed subclassification to guide surgical management

Background: Optimal surgical management of monochorionic diamniotic twins complicated by selective intrauterine growth restriction (SIUGR) type II is unknown. Surgical management may involve selective laser photocoagulation of communicating vessels (SLPCV), which offers the possibility of dual twin survivors versus umbilical cord occlusion (UCO) of the SIUGR twin.Objective: To identify patient characteristics associated with SIUGR twin survival for those undergoing SLPCV.Study design: All patients studied were those who underwent fetal treatment for SIUGR type II at our center from 2006-2018. SIUGR type II was defined as an estimated fetal weight <10th percentile with persistent absent and/or reversed end diastolic flow in the umbilical artery of the SIUGR twin, in the absence of twin-twin transfusion syndrome. Patients were offered SLPCV versus UCO, and those undergoing SLPCV, patient characteristics associated with 30-day survival of the SIUGR twin were examined using bivariate analysis and multiple logistic regression models.Results: Fifty-four consecutive SIUGR type II patients were treated, 45 via SLPCV and nine via UCO. Of the 45 SLPCV cases, there were 16 (35.6%) with SIUGR twin (and dual) survival. SIUGR twin survival appeared associated with middle cerebral artery (MCA) peak systolic velocity (psv) <1.5 multiples of the median, and forward atrial systolic flow in the ductus venosus (DV). In a post hoc analysis, we subsequently categorized patients as: SIUGR type IIa (N = 32 (71.1%)): normal MCA psv, and normal DV waveform, versus SIUGR type IIb (N = 13 (28.9%)): MCA psv ≥1.5 multiples of the median, and/or DV with absent or reversed atrial systolic flow. Thirty-day survival of the SIUGR twin was 50% for type IIa and 0% for type IIb.Conclusion: Over one-third of SIUGR type II patients experienced dual survival after treatment with laser surgery. Normal MCA psv and normal DV waveforms were associated with SIUGR type II survival of the SIUGR twin. Post hoc exploration and subclassification of SIUGR type II patients by preoperative Doppler indices created two groups, one (type IIa) with 50% survival and one (type IIb) with 0% survival of the SIUGR twin after laser surgery. Upon further confirmation, these findings may provide guidance for counseling patients and conducting fetal therapy.

Percent Absent End-Diastolic Velocity in the Umbilical Artery and Donor Twin Demise after Laser Surgery for Twin-Twin Transfusion Syndrome

INTRODUCTION

To examine the association of preoperative absent end-diastolic velocity (AEDV) and percent AEDV (%AEDV) in the umbilical artery (UA) with donor twin intrauterine fetal demise (IUFD) after laser surgery for twin-twin transfusion syndrome (TTTS).

METHODS

We performed a retrospective study of stage III/IV TTTS patients who underwent laser surgery from 2006 to 2016. Donors were classified as having preoperative persistent AEDV (yes/no). %AEDV was calculated for those with AEDV as 100× the proportion of the total cardiac cycle in AEDV. Using multiple logistic regression, we tested for an association between the outcome donor IUFD and AEDV risk factors (part 1) and %AEDV (part 2). We stratified these analyses by estimated fetal weight (EFW) discordance ≥20 versus <20%.

RESULTS

Of 344 cases, 153 (44.5%) donors had AEDV. Part 1 did not confirm an independent association between AEDV and donor IUFD. In the part 2 analysis of the 153 patients with AEDV, %AEDV was a positive risk factor for donor IUFD only in those with discordance (n = 129) (OR 1.04, 95% CI 1.01-1.08, p = 0.0278) when adjusting for %EFW discordance, presence of arterioarterial anastomoses, and multiparity.

DISCUSSION

Among stage III/IV TTTS patients with AEDV, %AEDV was a risk factor for donor IUFD only in the presence of EFW discordance.

Update on twin-to-twin transfusion syndrome

Twin-to-twin transfusion syndrome (TTTS) is a serious complication that affects 10-15% of monochorionic multiple pregnancies. Communicating placental vessels on the chorionic plate between the donor and recipient twin are responsible for the imbalance of blood flow. There is evidence for the superiority of fetoscopic laser ablation over serial amnioreductions regarding survival and neurological outcome for stages II-IV TTTS. However, the optimal management of stage I is still debated. The "Solomon" technique showed a significant reduction in recurrent TTTS and post laser twin anemia-polycythemia sequence (TAPS) in comparison to the selective laser method without improvement in perinatal mortality or neonatal morbidity. Survival rates after fetoscopic laser surgery have significantly increased over the last 25 years. High volume centers report up to 70% double survival and at least one survivor in >90%. Long-term neurodevelopmental impairment occurs in about 10% of children after laser surgery. In this review we discuss the optimal management, innovations in laser technique, long-term neurodevelopmental outcome, and future aspects of TTTS treatment.

Outcome reporting across randomized trials and observational studies evaluating treatments for twin-twin transfusion syndrome: systematic review

OBJECTIVE

Twin-twin transfusion syndrome (TTTS) is associated with significant mortality and morbidity. Potential treatments for the condition require robust evaluation. The aim of this study was to evaluate outcome reporting across observational studies and randomized controlled trials assessing treatments for TTTS.

METHODS

Cochrane Central Register of Controlled Trials, EMBASE and MEDLINE were searched from inception to August 2016. Observational studies and randomized controlled trials reporting outcome following treatment for TTTS in monochorionic-diamniotic twin pregnancy and monochorionic-triamniotic or dichorionic-triamniotic triplet pregnancy were included. Outcome reporting was systematically extracted and categorized.

RESULTS

Six randomized trials and 94 observational studies were included, reporting data from 20 071 maternal participants and 3199 children. Six different treatments were evaluated. Included studies reported 62 different outcomes, including six fetal, seven offspring mortality, 25 neonatal, six early childhood and 18 maternal/operative outcomes. Outcomes were reported inconsistently across trials. For example, when considering offspring mortality, 31 (31%) studies reported live birth, 31 (31%) reported intrauterine death, 49 (49%) reported neonatal mortality and 17 (17%) reported perinatal mortality. Four (4%) studies reported respiratory distress syndrome. Only 19 (19%) studies were designed for long-term follow-up and 11 (11%) of these reported cerebral palsy.

CONCLUSIONS

Studies evaluating treatments for TTTS have often neglected to report clinically important outcomes, especially neonatal morbidity outcomes, and most are not designed for long-term follow-up. The development of a core outcome set could help standardize outcome collection and reporting in TTTS studies. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Fetal interventional procedures and surgeries: a practical approach

The identification of congenital birth defects and fetal malformations continues to increase during the antenatal period with improved imaging techniques. Understanding of how to treat specific fetal conditions continues to improve outcomes from these treatment modalities. In an effort to further improvement in this field, we provide a review that begins with a brief background of fetal surgery including the history of fetal surgery, ethics surrounding fetal surgery, and considerations of how to treat the fetus during intervention. A synopsis of the most commonly encountered disease processes treated by fetal intervention/surgery including definitions, treatment modalities, and outcomes following fetal intervention/surgery is then provided. Within the sections describing each disease process, methodology is described that has helped with efficiency and success of procedures performed at our institution.

Twin-twin transfusion and laser therapy

PURPOSE OF REVIEW

Twin-to-twin transfusion syndrome (TTTS) is an uncommon, but dangerous, complication of monochorionic diamniotic twin gestations. The purpose of this review is to provide an update on the evolving treatments in TTTS as it pertains primarily to laser photocoagulation, as well as to provide recently published information on outcomes.

RECENT FINDINGS

The Solomon laser technique, in which selective fetoscopic laser photocoagulation is first performed and then followed by laser of the vascular equator from one side of the placenta to the other, reduces TTTS complications of twin anemia-polycythemia syndrome and recurrent TTTS. The addition of fetal echocardiography to the historical staging of TTTS adds important information that may guide future therapies. The postlaser ablation rate of neurodevelopmental delay in TTTS has recently been reported to be 14%. Cotwin demise is a significant complication of untreated TTTS and survival carries a 25% risk of cystic periventricular leukomalacia, middle cerebral artery infarction, and injury to other central nervous system structures as noted by neuroimaging.

SUMMARY

Laser therapy for TTTS is clearly the only therapy that halts the disease process, allows both fetuses an opportunity to survive and protects a surviving cotwin in the event of the demise of one twin. Laser techniques have evolved greatly over the last 25 years and recent reports with the addition of the Solomon technique appearing to reduce some postlaser complications (twin anemia-polycythemia sequence and recurrent TTTS). Future focus of TTTS therapy should be centered on understanding the pathophysiology of the disease better with improvement in staging of the disease and on comparison of different laser techniques with the overall goal of not only increasing twin survival rates but also reducing long term neurodevelopmental morbidity.

Laser Treatment of Twin–to–Twin Transfusion Syndrome

Objective: Laser ablation of all placental vascular anastomoses is the optimal treatment for twin–twin transfusion syndrome (TTTS). However, two important controversies are apparent in the literature: (a) a gap between concept and performance, and (b) controversy regarding whether all the anastomoses can be identified endoscopically and whether blind lasering of healthy placenta is justified. The purpose of this article is: (a) to address the potential source of the gap between concept and performance by analyzing the fundamental steps needed to successfully accomplish the surgery, and (b) to discuss the resulting competency benchmarks reported with the different surgical techniques. Materials and Methods: Laser surgery for TTTS can be broken down into two fundamental steps: (1) endoscopic identification of the placental vascular anastomoses, (2) laser ablation of the anastomoses. The two steps are not synonymous: (a) regarding the endoscopic identification of the anastomoses, the non-selective technique is based upon lasering all vessels crossing the dividing membrane, whether anastomotic or not. The selective technique identifies and lasers only placental vascular anastomoses. The Solomon technique is based on the theory that not all anastomoses are endoscopically visible and thus involves lasering healthy areas of the placenta between lasered anastomoses, (b) regarding the actual laser ablation of the anastomoses, successful completion of the surgery (i.e., lasering all the anastomoses) can be measured by the rate of persistent or reverse TTTS (PRTTTS) and how often a selective technique can be achieved. Articles representing the different techniques are discussed. Results: The non-selective technique is associated with the lowest double survival rate (35%), compared with 60–75% of the Solomon or the Quintero selective techniques. The Solomon technique is associated with a 20% rate of residual patent placental vascular anastomoses, compared to 3.5–5% for the selective technique (p < .05). Both the Solomon and the selective technique are associated with a 1% risk of PRTTTS. Adequate placental assessment is highest with the selective technique (99%) compared with the Solomon (80%) or the ‘standard’ (60%) techniques (p < .05). A surgical performance index is proposed. Conclusion: The Quintero selective technique was associated with the highest rate of successful ablation and lowest rate of PRTTTS. The Solomon technique represents a historical backward movement in the identification of placental vascular anastomoses and is associated with higher rate of residual patent vascular communications. The reported outcomes of the Quintero selective technique do not lend support to the existence of invisible anastomoses or justify lasering healthy placental tissue.

Comparison between laparoscopically assisted and standard fetoscopic laser ablation in patients with anterior and posterior placentation in twin-twin transfusion syndrome: a single center study

BACKGROUND

The objective of our study was to compare outcomes following laparoscopically assisted procedure (LAP group) with those seen following a standard approach used in patients with either an anterior placenta (SAP group) or posterior placenta (SPP group).

METHOD

This was a retrospective review of all the cases of twin-twin transfusion syndrome treated in our fetal center from October 2011 to July 2013. Technical characteristics of the procedure, perinatal survival outcome, and maternal morbidity were compared.

RESULTS

The laser procedure time was significantly longer in the SAP group (44 ± 10 min) in contrast with SPP (19.3 ± 13.9 min, p < 0.001) and LAP group (32 ± 11 min, p: 0.012). Preterm premature rupture of membranes (PPROM) before 32 and 34 weeks of pregnancy was significantly more common with LAP versus SAP and SPP (90 vs 33.3 and 70.8% for 32 weeks respectively, p: 0.015; 100 vs 50 and 79.1% for 34 weeks respectively, p: 0.021). In terms of maternal morbidity and neonatal outcome, there were no significant differences between the three groups.

CONCLUSION

LAP may be useful in cases where SAP is not feasible. Despite the increased risk of PPROM with LAP, perinatal survival and maternal outcomes are similar to that seen in SAP and SPP patients.

Perinatal outcome after laser surgery for triplet gestations with feto-fetal transfusion syndrome

OBJECTIVE

The objective of this study is to evaluate the outcomes of fetoscopic laser photocoagulation (FLP) for a triplet gestation with feto-fetal transfusion syndrome (FFTS).

METHOD

On the basis of chorionicity, perinatal outcome at 28 days in triplets with FFTS after FLP were evaluated.

RESULTS

Fetoscopic laser photocoagulation was completed for all 16 cases including nine dichorionic triamniotic (DT) cases and seven monochorionic triamniotic (MT) cases. The placenta was located anteriorly in six cases. The median gestational age at surgery was 21 (16-25) weeks, and the median operation time was 51 (25-125) minutes. Several technical maneuvers to complete the procedure in MT, such as trocar assistance in two cases, intentional septostomy of the dividing membrane in one, and double uterine entry in one, were used. The median gestational age at delivery was 31 (23-34) weeks. Overall perinatal survival in DT was 74% and that of MT was 95%. All 16 cases resulted in at least one survival, whereas three neonates survived in 44% of DT cases and in 86% of MT cases. Two MT neonates suffered severe intraventricular hemorrhages.

CONCLUSIONS

Fetoscopic laser photocoagulation for FFTS in MT as well as DT triplets seems a valuable treatment.

Establishing a national program for fetoscopic guided laser occlusion for twin-to-twin transfusion syndrome in Sweden

OBJECTIVE

To describe the establishment of the fetoscopic guided laser occlusion (FLOC) technique for treatment of twin-to-twin transfusion syndrome (TTTS) and the initial results in a Swedish national center.

DESIGN

Retrospective, descriptive study.

SETTING

Tertiary level university hospital.

POPULATION

All referred and treated cases suffering significant TTTS.

METHODS

The present study includes all cases of FLOC for TTTS at the Center of Fetal Medicine at Karolinska University Hospital, Stockholm, Sweden from October 2001 until December 2009. Patients were referred from all over Sweden and a few from other Nordic countries. The patients were evaluated with ultrasound examination between gestational ages of 18 and 26 weeks. Data from patients were extracted from our electronic medical record system and, in addition, families were contacted and medical records requested from referring hospitals.

MAIN OUTCOME MEASURES

Pregnancies with one or more surviving infants after FLOC treatment categorized according to stage of TTTS.

RESULTS

In 75% of pregnancies, one or more infant was born alive. At stage I, both infants survived in one pregnancy and one survived in the second. There was no significant difference between cases at stage II or III, i.e. 73 vs. 78% of pregnancies resulted in one or more surviving infant. At stage IV, 66% of pregnancies ended with one or more surviving infant.

CONCLUSIONS

Treatment of TTTS is feasible in a rather small country like Sweden, with comparable results to other centers. There are strong arguments for centralization and further improvement of this kind of highly specialized treatment.

Use of the Learning Curve-Cumulative Summation test for quantitative and individualized assessment of competency of a surgical procedure in obstetrics and gynecology: fetoscopic laser ablation as a model

OBJECTIVE

We sought to determine the learning curve (LC) for fetoscopic laser photocoagulation (FLP) as a model for the evaluation of training in surgical procedures.

STUDY DESIGN

A retrospective review of consecutive case series of FLP from 2 centers with 3 operators (operator I [O-I], observer trained; operator II [O-II], hands-on trained; and operator III [O-III], clinical fellow) was performed and the LC-cumulative summation (CUSUM) test was plotted.

RESULTS

The acceptable and unacceptable success rates for at least 1 fetus survival after FLP were set at 82% and 70%, respectively, from a systematic review. A total of 171 consecutive cases were performed by the 3 operators (O-I, 91; O-II, 49; and O-III, 31). From LC-CUSUM test O-I needed 60 procedures, O-II needed 20 procedures, and O-III needed 20 procedures to reach an acceptable performance rate for at least 1 survivor.

CONCLUSION

The LC-CUSUM test can be used to accurately assess the LC in a surgical procedure in obstetrics and gynecology. Hands-on trained operators exhibit a shorter LC.