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Residual Anastomoses After Fetoscopic Laser Surgery in Twin-to-Twin Transfusion Syndrome: Frequency, Associated Risks and Outcome
Abstract
Fetoscopic laser coagulation of placental vascular anastomoses is considered to be the treatment of choice in severe twin-to-twin transfusion syndrome. The aim of fetoscopic laser surgery is to separate completely the inter-twin placental circulation. Incomplete laser coagulation may result in residual vascular anastomoses. The incidence and clinical implications of residual anastomoses in twin-to-twin transfusion syndrome treated with fetoscopic laser surgery has not yet been studied. We examined all placentas treated with fetoscopic laser surgery and delivered at our center between June 2002 and December 2005 with vascular injection using colored dyes. Presence of residual anastomoses was studied in association with adverse outcome and inter-twin hemoglobin difference at birth. Adverse outcome was defined as fetal demise, neonatal death or severe cerebral injury. The relation between residual anastomoses and placental localization (anterior or posterior uterine wall) was evaluated. A total of 52 laser-treated placentas were studied. Residual anastomoses were detected in 33% (17/52) of placentas. Adverse outcome was similar in the groups with and without residual anastomoses, 18% (6/34) and 29% (20/70), respectively (p=0.23). Large inter-twin hemoglobin differences (>5g/dL) were found in 65% (11/17) of cases with residual anastomoses and 20% (7/35) of cases without residual anastomoses (p<0.01). Anterior placental localization was not associated with a more frequent presence of residual anastomoses. In conclusion, residual anastomoses at our institution are seen in one-third of monochorionic placentas treated with fetoscopic laser surgery. Although residual anastomoses in our study were not associated with adverse outcome, they were often associated with neonatal hematological complications.
... This treatment requires precise identification and laser ablation of placental vascular anastomoses [3]. Despite recent advancements in instrumentation and imaging for TTTS [4], residual anastomoses still represent a major complication [5]. This may be explained considering the challenges, from the surgeon's side, of limited field of view (FoV) and constrained maneuverability of the fetoscope, especially for anterior placenta. ...
... We measure the performance of our framework using the structural similarity index measure (SSIM) over a number (n) of frames, with n ∈ [1,5], for fair comparison with Bano et al. [8]. We call this metric s. ...
... International Journal of Computer Assisted Radiology and Surgery Fig. 4 Boxplots of s over n frames (with n in range [1][2][3][4][5]) obtained with (blue) SIFT, (red) [8] and (orange) the proposed framework where u and v are the groundtruth displacements of the four corners, and û and v are the estimated displacements. For qualitative evaluation, the registered frames are blended together using the Mertens-Kautz-Van Reeth exposure fusion algorithm [31] to tackle the non-uniform light exposure of the FoV along the fetoscopic video sequence. ...
Purpose
In twin-to-twin transfusion syndrome (TTTS), abnormal vascular anastomoses in the monochorionic placenta can produce uneven blood flow between the two fetuses. In the current practice, TTTS is treated surgically by closing abnormal anastomoses using laser ablation. This surgery is minimally invasive and relies on fetoscopy. Limited field of view makes anastomosis identification a challenging task for the surgeon.
Methods
To tackle this challenge, we propose a learning-based framework for in vivo fetoscopy frame registration for field-of-view expansion. The novelties of this framework rely on a learning-based keypoint proposal network and an encoding strategy to filter (i) irrelevant keypoints based on fetoscopic semantic image segmentation and (ii) inconsistent homographies.
Results
We validate our framework on a dataset of six intraoperative sequences from six TTTS surgeries from six different women against the most recent state-of-the-art algorithm, which relies on the segmentation of placenta vessels.
Conclusion
The proposed framework achieves higher performance compared to the state of the art, paving the way for robust mosaicking to provide surgeons with context awareness during TTTS surgery.
... Lopriore et al. reported an incidence of 33% of RPPVAS in 52 TTTS patients treated with laser at their institution. 24 In comparison, the rate of RPPVAS after SLPCV by our groups, using a common technique and common technology, has consistently been the contrary, if the terminal end of an artery was followed by a vein returning to the other twin, this was identified labeled as AV anastomosis. A-A anastomoses were apparent since the artery of one twin would continue as an artery to the other twin as well. ...
... Given that the Solomon technique is still associated with approximately 20% of RPPVAS, the initial rationale for the technique, that is, to reduce the high rate of RPPVAS, does not appear to hold. Furthermore, given that the proponents of the Solomon technique have also shown that most missed anastomoses are located in the margins of the placenta, 24 lasering inexistent placental vascular anastomoses in otherwise healthy placental tissue between vascular anastomoses within the main body of the placenta is incongruent with the rationale (Table 3 and Fig. 1). Altogether, the Solomon technique would seem to represent a backward step in the ability to correctly identify all of the placental vascular anastomoses, by accepting the unproven theory of the presence of nonvisible placental vascular anastomoses on otherwise healthy-appearing fetal surface of the placenta. ...
... 35 In another report of 123 patients, surgery could not be completed in five cases for a stuck twin obscuring the equator (2), poor visualization (2), and a large anastomotic vessel (1). 24 Obviously, the goal is to try to perform the surgery selectively as close to 100% of the time as possible. 22,34,36 ...
... Anemia after demise of one of the fetuses was also noted as a complication, which is indirect evidence of residual patent placental vascular anastomoses as well. Lopriore et al. (2006) reported an incidence of 33% of residual patent placental vascular anastomoses in 52 TTTS patients treated with laser at their institution. In comparison, the rate of residual patent placental vascular anastomoses after SLPCV by our group, using similar technique and technology, has consistently been less than 5%, with no anemia after demise of the co-twin, and an incidence of reverse or persistent TTTS of only 1-1.5% (USFetus Consortium; Quintero, 2007). ...
... Given that the Solomon technique is still associated with approximately 20% of residual patent placental vascular anastomoses, the initial rationale for the technique, that is, to reduce the high rate of residual patent placental vascular anastomoses, does not appear to hold. Furthermore, given that the proponents of the Solomon technique have also shown that most missed anastomoses are located in the margins of the placenta (Lopriore et al., 2006), lasering inexistent placental vascular anastomoses in otherwise healthy placental tissue between vascular anastomoses within the main body of the placenta is incongruent with the rationale (Table 3, Figure 1(a) and (b)). Altogether, the Solomon technique would seem to represent a step backwards in the ability to correctly identify all of the placental vascular anastomoses, by accepting the unproven theory of the presence of non-visible placental vascular anastomoses on the otherwise healthy appearing fetal surface of the placenta. ...
... For example, in that same article, the authors showed that they were able to perform a selective surgery in only 34% of cases (Stirnemann et al., 2008). In another report of 123 patients, surgery could not be completed in five cases for a stuck twin obscuring the equator (2), poor visualization (2) and a large anastomotic vessel (1) (Lopriore et al., 2006). Obviously, the goal is to try to perform the surgery selectively as close to 100% of the time as possible (Chmait et al., 2011;Crisan et al., 2010;Kontopoulos et al., 2015). ...
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.
... However, irrespective of surgical technique, the complete occlusion of anastomoses is not always achieved, as prior literature has documented at varying incidences upon placental examination. [10][11][12][13][14][15] There have been no previous systematic reviews describing or quantifying these residual anastomoses, or investigating factors that may influence numbers of residual anastomoses. The impact that residual anastomoses have on fetal outcomes also requires further investigation. ...
... Nineteen included studies presented data on residual anastomoses following laser ablation within MC twins complicated by TTTS. 4,[10][11][12][13][14][15]33,34,[36][37][38][39]41,42,44,45,47,48,50 One study was an RCT, two were prospective cohort studies, seven were retrospective cohort studies, and nine were case series papers. ...
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.
... Despite all the advancements in instrumentation and imaging for TTTS (Cincotta and Kumar, 2016;Maselli and Badillo, 2016), residual anastomoses after monochorionic placentas treated with fetoscopic laser surgery still represent an issue (Lopriore et al., 2007). This may be explained considering challenges from the surgeon's side, such as limited field of view (FoV), poor visibility and high inter-subject variability. ...
Fetoscopy laser photocoagulation is a widely adopted procedure for treating Twin-to-Twin Transfusion Syndrome (TTTS). The procedure involves photocoagulation pathological anastomoses to regulate blood exchange among twins. The procedure is particularly challenging due to the limited field of view, poor manoeuvrability of the fetoscope, poor visibility, and variability in illumination. These challenges may lead to increased surgery time and incomplete ablation. Computer-assisted intervention (CAI) can provide 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 challenge, we released the first largescale multicentre TTTS dataset for the development of generalized and robust semantic segmentation and video mosaicking algorithms. 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. 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. The challenge provided an opportunity for creating 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-centre fetoscopic data, we provide a benchmark for future research in this field.
... Regarding the more advanced stages of TTTS, most studies conclude that fetoscopic laser coagulation is the gold standard for treatment of severe TTTS at midgestation (16-26 gw). 41,42,[48][49][50][51][52][53] TAPS Twin anemia polycythemia sequence (TAPS) is a chronic form of unbalanced twin-to-twin transfusion through tiny placental anastomoses in MC twins, leading to anemia in the donor twin and polycythemia in the recipient fetus. 54 Also, TAPS is an uncommon complication, belonging to MC twins only. 1 ...
... This treatment requires precise identification and laser ablation of placental vascular anastomoses (Beck et al., 2012). Despite recent advancements in instrumentation and imaging for TTTS (Cincotta and Kumar, 2016), residual anastomoses after ablation still represent a major complication (Lopriore et al., 2007). This may be explained considering the challenges, from the surgeon's side, of limited Field of View (FoV) and constrained manoeuvrability of the fetsocope, especially for anterior placenta. ...
In Twin-to-Twin Transfusion Syndrome (TTTS), abnormal vascular anastomoses in the monochorionic placenta can produce uneven blood flow between the two fetuses. In the current practice, TTTS is treated surgically by closing abnormal anastomoses using laser ablation. This surgery is minimally invasive and relies on fetoscopy. Limited field of view makes anastomosis identification a challenging task for the surgeon. To tackle this challenge, we propose a learning-based framework for in-vivo fetoscopy frame registration for field-of-view expansion. The novelties of this framework relies on a learning-based keypoint proposal network and an encoding strategy to filter (i) irrelevant keypoints based on fetoscopic image segmentation and (ii) inconsistent homographies. We validate of our framework on a dataset of 6 intraoperative sequences from 6 TTTS surgeries from 6 different women against the most recent state of the art algorithm, which relies on the segmentation of placenta vessels. The proposed framework achieves higher performance compared to the state of the art, paving the way for robust mosaicking to provide surgeons with context awareness during TTTS surgery.
... The process involves surgeons searching for abnormal vascular anastomoses using the fetoscope. The field of view of a fetoscope is limited compared to the area being operated, and this may lead to anastomoses being missed by the surgeon and incomplete treatment [19]. Other common problems encountered include unusual placenta position (anterior or posterior placenta), poor visibility, and limited maneuverability. ...
Purpose:
Fetoscopic laser photocoagulation is a minimally invasive procedure to treat twin-to-twin transfusion syndrome during pregnancy by stopping irregular blood flow in the placenta. Building an image mosaic of the placenta and its network of vessels could assist surgeons to navigate in the challenging fetoscopic environment during the procedure.
Methodology:
We propose a fetoscopic mosaicking approach by combining deep learning-based optical flow with robust estimation for filtering inconsistent motions that occurs due to floating particles and specularities. While the current state of the art for fetoscopic mosaicking relies on clearly visible vessels for registration, our approach overcomes this limitation by considering the motion of all consistent pixels within consecutive frames. We also overcome the challenges in applying off-the-shelf optical flow to fetoscopic mosaicking through the use of robust estimation and local refinement.
Results:
We compare our proposed method against the state-of-the-art vessel-based and optical flow-based image registration methods, and robust estimation alternatives. We also compare our proposed pipeline using different optical flow and robust estimation alternatives.
Conclusions:
Through analysis of our results, we show that our method outperforms both the vessel-based state of the art and LK, noticeably when vessels are either poorly visible or too thin to be reliably identified. Our approach is thus able to build consistent placental vessel mosaics in challenging cases where currently available alternatives fail.
... Despite all the advancements in instrumentation and imaging for TTTS [11], residual anastomoses still represent a major complication in monochorionic placentas treated with fetoscopic laser surgery [12]. This may be explained considering the challenges in identifying anastomoses in conditions of poor visibility and constrained maneuverability of the fetsocope, especially in the presence of anterior placenta due to the unfavourable viewing angle. ...
Fetoscopy laser photocoagulation is a widely used procedure for the treatment of Twin-to-Twin Transfusion Syndrome (TTTS), that occur in mono-chorionic multiple pregnancies due to placental vascular anastomoses. This procedure is particularly challenging due to limited field of view, poor manoeuvrability of the fetoscope, poor visibility due to fluid turbidity, variability in light source, and unusual position of the placenta. This may lead to increased procedural time and incomplete ablation, resulting in persistent TTTS. Computer-assisted intervention may help overcome these challenges by expanding the fetoscopic field of view through video mosaicking and providing better visualization of the vessel network. However, the research and development in this domain remain limited due to unavailability of high-quality data to encode the intra- and inter-procedure variability. Through the \textit{Fetoscopic Placental Vessel Segmentation and Registration (FetReg)} challenge, we present a large-scale multi-centre dataset for the development of generalized and robust semantic segmentation and video mosaicking algorithms for the fetal environment with a focus on creating drift-free mosaics from long duration fetoscopy videos. In this paper, we provide an overview of the FetReg dataset, challenge tasks, evaluation metrics and baseline methods for both segmentation and registration. Baseline methods results on the FetReg dataset shows that our dataset poses interesting challenges, offering large opportunity for the creation of novel methods and models through a community effort initiative guided by the FetReg challenge.
... Despite all the advancements in instrumentation and imaging for TTTS [9], residual anastomoses still represent a high percentage after monochorionic placentas treated with fetoscopic laser surgery [17]. This may be explained considering the challenges in identifying anastomoses in conditions of poor visibility. ...
Fetoscopy laser photocoagulation is a widely used procedure for the treatment of Twin-to-Twin Transfusion Syndrome (TTTS), that occur in mono-chorionic multiple pregnancies due to placental vascular anastomoses. This procedure is particularly challenging due to limited field of view, poor manoeuvrability of the fetoscope, poor visibility due to fluid turbidity, variability in light source, and unusual position of the placenta. This may lead to increased procedural time and incomplete ablation, resulting in persistent TTTS. Computer-assisted intervention may help overcome these challenges by expanding the fetoscopic field of view through video mosaicking and providing better visualization of the vessel network. However, the research and development in this domain remain limited due to unavailability of high-quality data to encode the intra- and inter-procedure variability. Through the Fetoscopic Placental Vessel Segmentation and Registration (FetReg) challenge, we present a large-scale multi-centre dataset for the development of generalized and robust semantic segmentation and video mosaicking algorithms for the fetal environment with a focus on creating drift-free mosaics from long duration fetoscopy videos. In this paper, we provide an overview of the FetReg dataset, challenge tasks, evaluation metrics and baseline methods for both segmentation and registration. Baseline methods results on the FetReg dataset shows that our dataset poses interesting challenges, which can be modelled and competed for through our crowd-sourcing initiative of the FetReg challenge.
... The incidence of residual anastomoses after FLS using the standard selective technique was reported to be up to 30% (Lopriore et al., 2007); thus, the Solomon technique, in which the entire vascular equator is ablated, was developed to reduce residual anastomoses (Lopriore, Slaghekke et al., 2009;Slaghekke et al., 2014). Since a randomized controlled trial revealed that the Solomon technique reduced the risk of complications associated with residual anastomoses (Slaghekke et al., 2014), this technique has been widely adopted at fetal treatment centers around the world (Akkermans et al., 2015). ...
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.
... Based on abstract review, 54 of these publications were selected to be reviewed in their entirety [1,2,4,5,7,[9][10][11][12]16,19,. The secondary search of bibliographies produced three additional publications which were also reviewed in their entirety for a total 57 publications [6,66,67]. The publications are detailed in Table 1 and reasons for exclusion are summarized in Figure 1. ...
Twin anemia polycythemia sequence (TAPS) is a rare complication of monochorionic diamniotic (MCDA) twins. Middle cerebral artery peak systolic velocity (MCA-PSV) measurements are used to screen for TAPS while fetal or neonatal hemoglobin levels are required for definitive diagnosis. We sought to perform a systematic review of the efficacy of MCA-PSV in diagnosing TAPS. Search criteria were developed using relevant terms to query the Pubmed, Embase, and SCOPUS electronic databases. Publications reporting diagnostic characteristics of MCA-PSV measurements (i.e., sensitivity, specificity or receiver operator curves) were included. Each article was assessed for bias using the Quality Assessment of Diagnostic Accuracy Studies II (QUADAS II) tool. Results were assessed for uniformity to determine whether meta-analysis was feasible. Data were presented in tabular form. Among publications, five met the inclusion criteria. QUADAS II analysis revealed that four of the publications were highly likely to have bias in multiple areas. Meta-analysis was precluded by non-uniformity between definitions of TAPS by MCA-PSV and neonatal or fetal hemoglobin levels. High-quality prospective studies with consistent definitions and ultrasound surveillance protocols are still required to determine the efficacy of MCA-PSV in diagnosing TAPS. Other ultrasound findings (e.g., placenta echogenicity discordance) may augment Doppler studies.
... Fetoscopic treatment of TTTS aims at photocoagulating the abnormal vessels in the placenta using a fetoscopic camera with a retractable laser ablation tool in its working channel, interrupting the undesired blood transfusion from one twin to the other [20]. The technique has many challenges related to poor visibility [15], varying placenta position [8], and vessel identification [18] that can cause some target vessels to be missed [16]. To safely perform photocoagulation, the surgeon requires a clear view of the placenta and a clear path between the ablation tool and the target vessels. ...
Purpose:
Fetoscopic laser photocoagulation is a minimally invasive surgery for the treatment of twin-to-twin transfusion syndrome (TTTS). By using a lens/fibre-optic scope, inserted into the amniotic cavity, the abnormal placental vascular anastomoses are identified and ablated to regulate blood flow to both fetuses. Limited field-of-view, occlusions due to fetus presence and low visibility make it difficult to identify all vascular anastomoses. Automatic computer-assisted techniques may provide better understanding of the anatomical structure during surgery for risk-free laser photocoagulation and may facilitate in improving mosaics from fetoscopic videos.
Methods:
We propose FetNet, a combined convolutional neural network (CNN) and long short-term memory (LSTM) recurrent neural network architecture for the spatio-temporal identification of fetoscopic events. We adapt an existing CNN architecture for spatial feature extraction and integrated it with the LSTM network for end-to-end spatio-temporal inference. We introduce differential learning rates during the model training to effectively utilising the pre-trained CNN weights. This may support computer-assisted interventions (CAI) during fetoscopic laser photocoagulation.
Results:
We perform quantitative evaluation of our method using 7 in vivo fetoscopic videos captured from different human TTTS cases. The total duration of these videos was 5551 s (138,780 frames). To test the robustness of the proposed approach, we perform 7-fold cross-validation where each video is treated as a hold-out or test set and training is performed using the remaining videos.
Conclusion:
FetNet achieved superior performance compared to the existing CNN-based methods and provided improved inference because of the spatio-temporal information modelling. Online testing of FetNet, using a Tesla V100-DGXS-32GB GPU, achieved a frame rate of 114 fps. These results show that our method could potentially provide a real-time solution for CAI and automating occlusion and photocoagulation identification during fetoscopic procedures.
... Placental injection studies after laser therapy have revealed that residual anastomoses are present in over 30% of placentas Article highlights • Twin-twin transfusion syndrome (TTTS) is caused by intertwin shifts of blood through placental anastomoses in monochorionic twin pregnancies • Fetoscopic laser surgery is the primary treatment for TTTS and has improved with the development of new techniques over the past decades • The Solomon technique aims to separate the twins' circulations completely and has been shown to decrease the incidence of postlaser twin anemia-polycythemia sequence (TAPS) and recurrence of TTTS • Brain injury and long-term neurodevelopmental impairment remain major concerns after TTTS, but fortunately the incidences of both have decreased significantly over time • Centralization in high output fetal therapy centers is crucial to guarantee the best quality of care in rare diseases needing highly specialized interventions like TTTS and laser surgery [40,41]. Residual anastomoses can cause post-laser TAPS or recurrence of TTTS and these complications are linked to adverse fetal, neonatal and long-term outcomes [42,43]. ...
Introduction: Twin-twin transfusion syndrome (TTTS) is a devastating complication of monochorionic twin pregnancy and remains a major challenge for worldwide fetal medicine specialists. In TTTS, inter-twin transfusion through vascular anastomoses in the shared placenta leads to severe hemodynamic imbalance. This review summarizes the current knowledge of TTTS.
Areas covered: The most recent insights concerning the management of TTTS, as well as fetal and neonatal complications are described. Relevant articles were selected based on a Pubmed search using the keywords below. Understanding of the underlying pathophysiology has improved greatly as a result of placental injection studies. Advancements in antenatal management have led to increased perinatal survival and a decreased incidence of neonatal complications, including brain injury and neurodevelopmental impairment.
Expert opinion: Further opportunities for improvement comprise technological innovations in laser procedures and the prevention of preterm rupture of membranes with subsequent prematurity. A non-invasive treatment such as high-intensity focused ultrasound (HIFU) seems to hold promise for the future treatment of TTTS. Fetal MRI studies are important to improve our understanding of fetal brain injury and should relate their findings to long-term neurodevelopment. International collaboration and centralization of care are of paramount importance to ensure the best care for our patients.
... Similar to TTTS, it is characterized by anemia of the donor twin and polycythemia of the recipient twin. It occurs spontaneously in 3%-5% of MC twins after 26 weeks gestation (47) and in approximately 13% of cases treated with fetoscopic laser ablation for TTTS because of incomplete dichorionization (48). ...
The twin birth rate is increasing in the United States. Twin pregnancies can be dichorionic or monochorionic (MC). MC twins account for 20% of twin pregnancies but 30% of all-cause pregnancy-related complications. This article describes the imaging findings that establish chorionicity and amnionicity. Ideally, these are established in the first trimester when accuracy is high, but they can also be determined later in pregnancy. Complications unique to MC twin pregnancy include twin-twin transfusion syndrome, twin anemia polycythemia sequence, twin reversed arterial perfusion sequence, and selective fetal growth restriction. The US features, staging systems, and management of these complications are reviewed, and the consequences of MC twin demise are illustrated. Ongoing surveillance for these conditions starts at 16 weeks gestation. Monoamniotic (MA) twins are a small subset of MC twins. In addition to all of the MC complications, specific MA complications include cord entanglement and conjoined twinning. Radiologists must be able to determine chorionicity and amnionicity and should be aware of potential complications so that patients may be referred to appropriate regional specialized centers. A proposed algorithm for referral to specialized fetal treatment centers is outlined. Online supplemental material is available for this article.©RSNA, 2019.
... However, both of these modalities provide insufficient contrast to visualize small anastomosing vessels beneath the chorionic placental surface [8]. Missed anastomoses or incomplete photocoagulation are associated with an increased risk of recurrent TTTS, intrauterine fetal death and twin anemia polycythaemia sequence [9][10][11][12]. With the procedural aim of occluding all anastomoses and thereby separating the twins' circulations, the "Solomon technique" involves photocoagulation of the entire vascular equator [12,13]. ...
Minimally invasive fetal interventions require accurate imaging from inside the uterine cavity. Twin‐to‐twin transfusion syndrome (TTTS), a condition considered in this study, occurs from abnormal vascular anastomoses in the placenta that allow blood to flow unevenly between the fetuses. Currently, TTTS is treated fetoscopically by identifying the anastomosing vessels, and then performing laser photocoagulation. However, white light fetoscopy provides limited visibility of placental vasculature, which can lead to missed anastomoses or incomplete photocoagulation. Photoacoustic (PA) imaging is an alternative imaging method that provides contrast for haemoglobin, and in this study, two PA systems were used to visualise chorionic (fetal) superficial and subsurface vasculature in human placentas. The first system comprised an optical parametric oscillator for PA excitation and a 2D Fabry‐Pérot cavity ultrasound sensor; the second, light emitting diode arrays and a 1D clinical linear‐array ultrasound imaging probe. Volumetric photoacoustic images were acquired from ex vivo normal term and TTTS treated placentas. It was shown that superficial and subsurface branching blood vessels could be visualised to depths of approximately 7 mm, and that ablated tissue yielded negative image contrast. This study demonstrated the strong potential of PA imaging to guide minimally invasive fetal therapies. This article is protected by copyright. All rights reserved.
... Apesar da terapia laser constituir o tratamento de escolha nas situações de STFF, a presença de anastomoses residuais (AR) constitui um problema que pode ser detetado em mais de um terço dos casos 53,54 . A maioria das AR situam-se nas margens da placenta e são de diâmetro reduzido (inferior a 1mm) 55 . ...
Twin-Twin Transfusion Syndrome affects 10-15% of monochorionic twin gestations. When left untreated, the perinatal mortality rates are above 90%. The surveillance of these pregnancies allows early detection of this syndrome to improve long-term outcomes. There are several forms of treatment but laser ablation is the first-line treatment in severe cases occurring before 26 weeks. In stage I the best management is not defined. The preterm birth influences negatively perinatal morbidity and mortality
... More precisely, surgeons perform a progressive visual exploration of the placenta, with the aim of localising and eliminating the anastomoses which allow a direct blood transfer between the two twins. Due to the difficulty of manipulating the fetoscope and due to the very limited field-of-view available at each timepoint to the surgeon, some anastomoses can be missed by the surgeon leading to an only incomplete treatment [13]. To assist a clinician during TTTS surgery, mosaicking approaches are desirable to create a map of the placenta from a video acquired during fetoscopy. ...
Purpose:
The standard clinical treatment of Twin-to-Twin transfusion syndrome consists in the photo-coagulation of undesired anastomoses located on the placenta which are responsible to a blood transfer between the two twins. While being the standard of care procedure, fetoscopy suffers from a limited field-of-view of the placenta resulting in missed anastomoses. To facilitate the task of the clinician, building a global map of the placenta providing a larger overview of the vascular network is highly desired.
Methods:
To overcome the challenging visual conditions inherent to in vivo sequences (low contrast, obstructions or presence of artifacts, among others), we propose the following contributions: (1) robust pairwise registration is achieved by aligning the orientation of the image gradients, and (2) difficulties regarding long-range consistency (e.g. due to the presence of outliers) is tackled via a bag-of-word strategy, which identifies overlapping frames of the sequence to be registered regardless of their respective location in time.
Results:
In addition to visual difficulties, in vivo sequences are characterised by the intrinsic absence of gold standard. We present mosaics motivating qualitatively our methodological choices and demonstrating their promising aspect. We also demonstrate semi-quantitatively, via visual inspection of registration results, the efficacy of our registration approach in comparison with two standard baselines.
Conclusion:
This paper proposes the first approach for the construction of mosaics of placenta in in vivo fetoscopy sequences. Robustness to visual challenges during registration and long-range temporal consistency are proposed, offering first positive results on in vivo data for which standard mosaicking techniques are not applicable.
... For this study, we excluded placentas with severe placental maceration due to fetal demise of one or more infants. Part of the placental data used in this study has been used in previous reports [3,5,6,11]. The study was approved by the Leiden University Medical Centre Medical Ethics Committee. ...
Objectives:
To evaluate the incidence of residual anastomoses (RA) after laser therapy for twin-twin transfusion syndrome (TTS) and investigate risk factors for incomplete laser surgery.
Material and methods:
All available TTS placentas treated with laser at our center between 2002 and 2016 were injected with color dye to assess the presence of RA. We evaluated the incidence of RA over the past 15 years by dividing the cohort into three time periods, and studied the association with risk factors and neonatal outcome.
Results:
Overall, RA were detected in 21.0% (78/371) of placentas. The incidence of RA decreased from 38.8% (26/67) in the initial period to 11.7% (16/137) in the most recent period (p < 0.001). On multivariate analysis, several risk factors were independently associated with the risk of RA, including Solomon laser technique (odds ratio [OR] 0.17, 95% CI 0.09-0.33) and estimation of surgical success (OR 19.28, 95% CI 8.17-45.49). Premature delivery and neonatal morbidity occurred more often in TTS cases with RA.
Conclusions:
The incidence of RA after laser therapy for TTS decreased significantly in the past 15 years and is now below 15% due to the use of the Solomon technique.
... Механизмы, приводящие к развитию СФФТ у монохориальных двоен с сосудистыми коммуникациями, остаются недостаточно понятными. Предполагается, что основным пусковым механизмом служит патология развития плаценты донора, результатом которой является повышение периферической резистентности плацентарного кровотока, что приводит к шунтированию крови к плоду-реципиенту [5][6][7][8][9][10][11]. Таким образом, страдание плода-донора происходит в результате гиповолемии (вследствие потери крови) и гипоксии (вследствие плацентарной недостаточности). ...
... However, fetoscopic laser surgery is not always complete and (small) residual anastomoses may be left patent in up to a third of cases, allowing persistence of TTTS or development of post-laser TAPS (see next paragraph) [19]. In both the situations, large inter-twin hemoglobin differences may still be found at birth [20]. Between 2002 and 2016, 47 TTTS twin pairs were treated with laser coagulation surgery and had residual anastomoses, resulting in post-laser TAPS or recurrent TTTS. ...
Introduction:
Monochorionic twins are at risk of severe complications including twin-twin transfusion syndrome (TTTS), twin anemia-polycythemia sequence (TAPS) and acute peripartum TTTS. The pathophysiology is based on inter-twin blood transfusion through placental vascular anastomoses. Areas covered: This review focuses on the incidence, management and outcome of neonatal hematological complications at birth in TTTS, TAPS and acute peripartum TTTS. Expert commentary: Hematological disorders are often present at birth in monochorionic twins and include acute or chronic anemia, polycythemia and thrombocytopenia. Routine measurement of complete blood counts in all complicated monochorionic twins is strongly recommended. Increased awareness on these disorders and correct diagnostic tests will lead to prompt and adequate management at birth.
... This condition occurs in approximately 5% of MCDA pregnancies spontaneously. It is seen even more frequently (12%) after fetoscopic laser treatment for TTTS [75][76][77][78][79][80] Poor neurodevelopmental outcomes including isolated cognitive delay, motor delay and cerebral palsy rates range greatly be- ...
Background/objectives:
Multiple pregnancies have tripled in the United States over the past 3 decades. Attributed to increasing maternal age at delivery but more so assisted reproductive technological advances, an effort has been made to decrease twinning through elective single embryo transfer. We sought to review and evaluate risks of monochorionic twinning as a predictable consequence of increasing utilization of elective single embryo transfer on perinatal outcomes. Primary outcomes included twinning rates, fetal anomalies, growth, preterm birth, and mortality. Secondary outcomes included neurological and pulmonary disability, intrauterine growth restriction, and congenital cardiac anomalies and twin-twin transfusion syndrome.
Data sources:
PubMed and Embase.
Results:
A total of 106 studies identified by systematic search met the inclusion criteria. The trend for lower numbers of embryos transferred has inadvertently led to an increase in monochorionic twinning. This is associated with worse outcomes compared to dichorionic twinning and singleton gestations for all outcomes studied.
Discussion:
Of great concern for monochorionic twins is the risk profile of significant morbidity and mortality. Transfer of 2 embryos should be considered to avoid higher risks inherent to the shared placental phenomena related to monochorionic twins.
... We considered TTTS and acute feto-fetal hemorrhage (AFFH) as differential diagnoses in the present case. TAPS has been described as a form of chronic fetofetal transfusion [9]. TTTS is also a form of chronic fetofetal transfusion, but TTTS leads to hypovolemia, oliguria and oligohydramnios in the donor ...
Twin anemia-polycythemia sequence (TAPS) is a group of disorders in monochorionic twins characterized by a large intertwin hemoglobin difference without amniotic fluid discordance. Reticulocyte count is used to diagnose this condition, but little is known about the role of erythroblasts, which are the prior stage of reticulocytes. In the present case of TAPS, the 25-yr-old Japanese mother showed no signs of oligohydramnios or polyhydramnios throughout gestation. The twins were born at 36 weeks and 6 days, weighing 2,648g and 1,994g. The intertwin hemoglobin difference in umbilical cord blood was (21.1-5.0=) 16.1g/dL and the donor twin showed signs of chronic anemia, including myocardial hypertrophy and pericardial effusion. Erythroblastosis of the donor twin was prolonged (53,088.5, 42,114.8 and 44,217.9/μL on days 0, 1 and 2, respectively). Erythroblastosis, which indicates chronic anemia, is also a good diagnostic indicator of TAPS.
... El análisis secundario del ensayo clínico aporta las diferencias estadísticamente significativas encontradas respecto al porcentaje de anastomosis residuales menores en la técnica de Solomon (32,33). Estas comunicaciones residuales pueden ser responsables de complicaciones severas postoperatorias como secuencia anemia policitemia en un 13-16% o recurrencia del síndrome de transfusión feto/fetal en un 7-14% (34,35). ...
Introduction: Between 15 to 20% of monochorionic diamniotic twin pregnancies are complicated by the twin-twin transfusion syndrome. It has a mortality greater than 90% and a significant morbidity, 50% in the surviving twin. The Solomon technique (laser photocoagulation of the main vascular channels of the chorionic plate surface along the entire vascular equator) has been suggested to reduce the recurrence, and prevent secondary complications without increasing adverse results. Methods: Systematic review of electronic searches of the literature from 2000 to 2015 (MEDLINE, EBSCO, OVID, PROQUEST, COCHRANE, Lilacs, and SciELO). We included review articles and original investigations comparing the standard photocoagulation technique with laser ablation against the Solomon technique. The primary results were reduction of Anemia Polycythemia Sequence incidence, twin-twin transfusion syndrome recurrence, perinatal mortality and severe neonatal morbidity. Results: Of 200 articles, we selected six: one clinical essay and its secondary analysis, two retrospective cohort studies, one systematic review and a study comparing neurodeve lopmental outcomes. The studies suggested a survival improvement in some fetuses using the Solomon technique, less twin-twin transfusion syndrome recurrence and Anemia Polycythemia Sequence without the presence of adverse effects. Conclusion: Solomon technique improves the survival of some twins, although we cannot conclude there is mortality improvement, because the studies do not have enough power to determine that.
... The goal of fetoscopic laser surgery is to coagulate all of the placental vascular anastomoses. However, in up to 33% of treated pregnancies inter-twin vascular connections may remain patent (Lewi et al., 2006;Lopriore et al., 2007). These residual patent anastomoses can cause severe complications such as TAPS and/or recurrent TTTS in up to 21% of pregnancies (Robyr et al., 2006;. ...
Monochorionic twin pregnancies can be complicated by twin-to-twin transfusion syndrome (TTTS). The best treatment option for TTTS is fetoscopic laser coagulation of the vascular anastomoses between donor and recipient. After laser therapy, up to 33% residual anastomoses were seen. These residual anastomoses can cause twin anemia polycythemia sequence (TAPS) and recurrent TTTS. In order to reduce the number of residual anastomoses and their complications, a new technique, the Solomon technique, where the whole vascular equator will be coagulated, was introduced. The Solomon technique showed a reduction of recurrent TTS compared to the selective technique. The incidence of recurrent TTTS after the Solomon technique ranged from 0% to 3.9% compared to 5.3–8.5% after the selective technique. The incidence of TAPS after the Solomon technique ranged from 0% to 2.9% compared to 4.2–15.6% after the selective technique. The Solomon technique may improve dual survival rates ranging from 64% to 85% compared to 46–76% for the selective technique. There was no difference reported in procedure-related complications such as intrauterine infection and preterm premature rupture of membranes. The Solomon technique significantly reduced the incidence of TAPS and recurrent TTTS and may improve survival and neonatal outcome, without identifiable adverse outcome or complications; therefore, the Solomon technique is recommended for the treatment of TTTS.
... Additionally, the operator should be trained to identify and characterize the vascular anastomoses of the monochorionic placenta. Placental dye injection examination [8,9] of the monochorionic placenta should be an important step before attempting laser surgery ( Fig. 1). All vessels on the placental surface can be precisely differentiated by fetoscopic inspection; arteries principally cross over veins and the color of arteries is dark blue due to deoxygenated blood, whereas veins appear bright red due to oxygenated blood from the placenta. ...
Fetoscopic laser surgery for severe twin-twin transfusion syndrome (TTTS) has become the optimal treatment choice since the release of the Eurofetus randomized clinical trial. These techniques have been adopted throughout the globe, and many institutions have instituted or will soon institute fetoscopic laser surgery procedures; however, laser surgery has a steep learning curve because of the following: challenging placental location, complex and unexpected communicating anastomoses, residual anastomoses after surgery, or discolored amniotic fluid. We have been performing laser surgery since 2002 in Japan; to date, we have compiled a series of 170 cases. Our data indicates a 78% of overall survival with 5% neonatal morbidity, 63% of survival of both twins, and 93% survival of at least one twin. The recurrent TTTS rate was 1% and the residual vessel rate was 3%. To improve the learning curve of laser surgery, the employment of various techniques is recommended to achieve a successful surgical outcome: (1) Mapping: before laser ablation, a very thorough mapping of vascular anastomoses should be done, and should be repeated after ablation; (2) Sequential order: obliteration of arterio-venous anastomoses from donor to recipient should be done first to avoid donor hypotension and/or anemia; (3) Trocar (cannula) assisted technique: Trocar assisted technique: Using gentle indent the trocar to the placenta by withdrawing the scope shortly, then anastomoses could be ablated easily; (4) Line method: to avoid residual anastomoses, the laser should draw a virtual line at the hemodynamic equator; The operator must be careful not to miss small anastomoses. These techniques can help achieve a successful outcome for fetoscopic laser surgery and improve the outcome for cases of severe TTTS.
Twin pregnancy is associated with an increased risk of perinatal and maternal complications, and early establishment of the chorionicity type defines this risk. In monochorionic (MC) pregnancies, the fetuses share the same placental mass and exhibit vascular anastomoses crossing the intertwin membrane, and the combination and pattern of anastomoses determine the primary clinical picture and occurrence of future complications.
Twin Anemia-Polycythemia Sequence (TAPS) was first described in 2006 after fetoscopic laser surgery in twin-to-twin transfusion syndrome (TTTS) twins, and in 2007, the first spontaneous cases were reported, recognizing TAPS as an individualized vascular identity in fetofetal transfusion syndromes. There are two types of TAPS: spontaneous (3-5%) and iatrogenic or postlaser (2-16%). TAPS consists of small diameter arteriovenous anastomoses (<1 mm) and low-rate, small-caliber AA anastomoses in the absence of amniotic fluid discordances. There are certain antenatal and postnatal diagnostic criteria, which have progressively evolved over time. New, additional secondary markers have been proposed, and their reliability is being studied. The best screening protocol for TAPS in MC twins is still a matter of debate.
This review provides a survey of the relevant literature on the epidemiology, vascular pathophysiology, underlying hemodynamic factors that regulate mismatched vascular connections, and diagnostic criteria of this condition. The aim is to increase awareness and knowledge about this recently identified and frequently unrecognized and misdiagnosed pathology.
Multiple pregnancies are associated with higher risks for both mother and babies. Women with multiple pregnancies have an increased risk of miscarriage, anemia, hypertensive disorders, haemorrhage, and postnatal illness. These pregnancies are more likely to need an operative delivery, and maternal mortality is generally 2.5 times that of singleton births. Fetuses are at increased risk for anatomic and genetic anomalies, growth abnormalities, prematurity, and several physiological problems related to monochorionicity. This book provides a much needed, up-to-date guide to the management of multiple pregnancies. Presented with a uniform approach to all chapters, information is easily navigable, evidence-based, and highly practical. Heavily illustrated, particularly with ultrasound images – the cornerstone of management of multiple pregnancies - this book will appeal to obstetricians and specialists in maternal-fetal medicine, midwives and ultrasonographers and will improve outcomes for mothers and babies.
Background
Complete coagulation of the vascular equator (i.e. ‘Solomon’ technique) has been suggested to reduce post-operative complications such as twin anemia polycythemia syndrome (TAPS) and recurrence of TTTS following fetoscopic laser coagulation of chorionic vessels for twin-twin transfusion syndrome (TTTS).
Objective
We aimed to evaluate the benefit of this technique on perinatal outcome, compared to 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, cases operated by selective surgery were matched to cases operated with the ‘Solomon’ technique according to gestational age at laser therapy, placental localization and Quintero stage, using propensity score matching.
Results
Within a total of 994 cases, 399 matched pairs were included in the analysis. Compared with selective ablation, the ‘Solomon’ technique was associated significantly improved survival: Overall twin survival at delivery and at discharge were 72 % vs 79% (p=0.003) and 69% vs 75% (p=0.006) respectively, double twin survival rate at discharge was 55% vs 65% (p=0.02), and the rate of intrauterine death dropped from 18% to 12% (p=0.003). The ‘Solomon’ technique significantly reduced the rate of TAPS (10% vs 4%, p=0.02), leading to fewer rescue secondary procedures (13% vs 7.3%, p=0.01). However, the ‘Solomon’ technique was associated with an increased risk of PROM, especially at early gestational ages (3.8% vs 11%, p<0.001 for PROM<24 weeks). Among the survivors at delivery, both groups had similar gestational age at birth. Both neonatal mortality and severe neurological morbidity were similar in both groups. However, an increased risk of bronchopulmonary dysplasia was found in the ‘Solomon’ group (4.5% vs 12%, p<0.001).
Conclusions
Although the risk of PPROM has increased, the introduction of the Solomon technique has significantly improved the perinatal outcome in pregnancies affected with TTTS.
In Twin-twin transfusion syndrome (TTTS) communicating placental vessels on the chorionic plate between the donor and recipient twin are responsible for the chronic imbalance of blood flow. Regarding treatment, evidence demonstrates that fetoscopic laser ablation is superior to serial amnioreductions in terms of survival and neurological outcome for stage II-IV TTTS. However, the optimal management of stage I TTTS remains controversial. It is well established that all chorionic plate anastomoses should be closed by laser. 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%. In this review we discuss the controversies in diagnosis and management of TTTS. In particular the optimal management in stage I cases, very early or late diagnosis, and the optimal laser technique. Furthermore, we will debate a stage related outcome after laser surgery and whether it is necessary at all to distinguish between stage I and II. Finally, the optimal timing as well as mode of delivery after TTTS laser treatment will be debated.
With advances in ultrasound, birth defects are increasingly detected during pregnancy and may be amenable to surgical correction before delivery, to improve outcomes. This essential book discusses the different birth defects that can be treated during pregnancy and the important anesthetic considerations for the mother and fetus undergoing these procedures. Experts in the fields of anesthesiology, maternal fetal medicine, surgery, and pediatrics have come together to develop the content of this book. Enhanced throughout with full color images and illustrations, the book covers important topics such as spina bifida, twin-twin transfusion syndrome, sacrococcygeal teratoma, and lung masses, as well as fetal cardiac intervention, intrauterine transfusion, ex utero intrapartum treatment, and multidisciplinary approaches to fetal surgery. An invaluable guide for pediatric and obstetric anesthesiologists, anesthesiology, obstetrics, and surgical trainees, nurse anesthetists, and maternal-fetal medicine specialists.
We propose an original method of complex assessment of the placental angioarchitechtonics based on computed tomography (CT) and morphological examination. A prerequisite condition of successful examination and assessment of the placental angioarchitechtonics is the pre-preparative stage including clearing of the placental and umbilical cord vessels from blood clots by placement of placenta into 10% hypertonic NaCl solution and then on a hygroscopic substrate. The major stage of this method is injection of contrast staining mixtures into the umbilical vessels followed by CT. The concentration of radiocontrast agent in water solution of gouache should be 70% for arteries and 15% for veins. The volumes of mixtures for contrast staining should be calculated according to the weight of the placenta. The contrast staining mixture was first injected into the catheterized unpaired umbilical vein, and then into both umbilical arteries. Each injection of the contrast staining mixture was visually inspected; then branching of the stained vessel was photographed and scanned by CT. The CT scans were used to construct 3D models of placental vessels and spectral color maps, which made it possible to examine the peculiarities of placental angioarchitechtonics, to identify and evaluate anastomoses of placental vessels, and to establish the type of these anastomoses.
Hematological disorders are often present at birth in monochorionic twins and are primarily due to the invariable presence of placental vascular anastomoses connecting the blood circulations of two fetuses. These vascular anastomoses may lead to unbalanced intertwin transfusion and play a key role in the development of severe complications such as twin-twin transfusion syndrome (TTTS) and twin anemia-polycythemia sequence (TAPS). In addition, vascular anastomoses may also allow rapid loss of blood from one twin to the other during delivery, the so-called acute peripartum TTTS. Hemoglobin differences at birth are often found in these complicated monochorionic twins and can help distinguish between the various complications.
With an increasing incidence of twin gestations, understanding the inherent risks associated with these pregnancies is essential in modern obstetrics. The unique differences in placentation in twins contribute to the increased risks. Monochorionic twins are susceptible to complications because of their unique placental architecture, including twin-to-twin transfusion syndrome, the twin anemia-polycythemia sequence, selective intrauterine growth restriction, and the twin reversed arterial perfusion sequence. Knowing the clinical correlations of placental anatomy in these gestations helps perinatal pathologists perform a more informed placental evaluation, allowing for better care for the mother and her children.
The increase in multiple gestation pregnancies has resulted in significant health care implications for both mother and child. Our ability to diagnose and intervene on an at-risk multi-gestation pregnancy has dramatically improved. It is important for the pediatric surgeon to be equipped with a basic fund of knowledge concerning these pregnancies. An understanding of amnionicity and chorionicity will equip the practitioner with the ability to identify which pregnancies are at risk for specific complications. This article highlights multi-gestation pregnancies that are monochorionic (single shared placenta) and can be complicated by twin-twin transfusion syndrome (TTTS), twin reversed arterial perfusion (TRAP) sequence, twin anemia polycythemia sequence (TAPS), or selective fetal intrauterine growth restriction (sIUGR). The risk of fetal demise is significant in these pregnancies. Understanding recommended surveillance and warning signs can alert surgeons to developing complications. Specialized fetal care centers possess the ability to intervene on these pregnancies in utero.
Obesity is a risk factor for complications in singleton and twin pregnancies; however, there are limited data regarding maternal body mass index (BMI) in the setting of twin-twin transfusion syndrome (TTTS). We hypothesized that increased BMI in TTTS is associated with adverse perinatal outcomes and vascular pathology. A retrospective study of twin reversed arterial perfusion (n = 4), selective intrauterine growth restriction (n = 10) and TTTS (n = 33) was conducted. Treatment included fetoscopic laser photocoagulation (FLP) (n = 35) or Solomon technique (n = 12). Ex vivo placental intravascular injections, immunohistochemistry, and perinatal outcomes were compared by maternal BMI. In pregnancy complicated by TTTS, 16/33 women were obese (BMI > 30 kg/m2) and 11/33 were overweight (BMI 25-29.9 kg/m2). Women who were overweight or obese had an increased rate of premature rupture of membranes (PPROM), cesarean delivery, and/or concomitant co-morbidities when compared to the normal weight group. Duration of neonatal intensive care unit (NICU) admission was longer in neonates of overweight/obese women versus normal weight. Placental examination of FLP sites in the obese group showed larger infarcts, increased adipose triglyceride lipase, and a proangiogenic phenotype. Increased BMI is common in our TTTS cohort and it is associated with higher rate of co-morbidity, PPROM, prolonged NICU stay, and an imbalance of placental metabolic and vascular mediators.
Proximate cord insertions are a variant of umbilical cord insertions that can be identified in monochorionic twins, making fetoscopic laser photocoagulation for twin-to-twin transfusion syndrome technically challenging. The existing literature is controversial for successful fetoscopic laser photocoagulation in twin-to-twin transfusion syndrome cases with proximate cord insertions. We presented two cases with twin-to-twin transfusion syndrome complicated by proximate cord insertions that underwent a successful laser ablation using our proposed technique.
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.
Laser ablation of all placental vascular anastomoses is the optimal treatment for twin-twin transfusion syndrome (TTTS). This requires proper endoscopic identification of the anastomoses and proper photocoagulation. However, two important controversies have recently become apparent: (1) a gap between concept and performance and (2) a question as to whether all the anastomoses can indeed be identified endoscopically and, therefore, whether blind lasering of healthy placental tissue between anastomoses (Solomon technique) is justified. The purpose of this article is to address the potential source of the gap between concept and performance by analyzing the fundamental steps needed to successfully accomplish the surgery and to discuss the resulting competency benchmarks reported with the different surgical techniques.
Twin-to-twin transfusion syndrome (TTTS) complicates 10% of monochorionic twin pregnancies and it is consequence of an unbalanced exchange blood through the vascular anastomoses at placental surface. If not treated, mortality rates in TTTS may be as high as 80 to 100%. Laser photocoagulation of the placental anastomoses is the first treatment option, however in some situations the damage of the placenta in the postpartum may become difficult the residual anastomoses identification. We propose a new non-invasive technique to assess the residual anastomoses using computed tomography (CT) scan data to generate a three-dimensional (3D) virtual placentoscopy.
The diagnosis of twin twin transfusion syndrome is an emergency and is generally easily done by ultrasound. Once the diagnosis is established patients should be referred rapidly for counselling and treatment within a network that can offer fetoscopic laser surgery as first-line treatment. Invasive treatments should be proscribed until then since they may impair fetoscopic visualization and therefore the overall prognosis, should this treatment be required. Depending on the presentation, other options may be offered such as cord coagulation, expectant management or delivery. Other treatment modalities such as amnioreduction or septostomy have almost no indications. Post-operative follow-up will be oriented by secondary hemodynamical complications and fetal neurological damage. An MRI may be a useful adjunct for ischemic/haemorrhagic brain injuries. Moderate prematurity may be justified, regarding the incidence of severe delayed complications.
Monochorionic twin placentation occurs in 20% of spontaneous twin pregnancies and almost 5% of those are obtained by medically assisted reproduction [1]. Monochorionic diamniotic (McDa) twin fetuses have the unique characteristic of living upon one single placenta. This situation can lead to specific complications including twin-to-twin transfusion syndrome (TTTS) [2, 3], twin-anemia-polycythemia sequence (TAPS) [4, 5], and selective intrauterine growth retardation (s-IUGR) [6]. These complications are likely to explain most of the 6- to 12-fold increase in perinatal mortality in monochorionic twins compared to dichorionic twins [7–10].
TTTS, also called twin oligohydramnios-polyhydramnios sequence (TOPS), complicates around 15% of monochorionic pregnancies irrespective of the mode of conception [7]. It is a hemodynamic, and probably hormonal, discordance secondary to imbalanced blood flows through the vascular anastomoses aforementioned [11–14]. The natural history of untreated TTTS leads to intra- or perinatal death in as many as 90% of cases [15, 16]. Impaired neurological development is reported in up to 50% of survivor-twins as a consequence of prematurity or of the intrauterine fetal demise (IUFD) of the co-twin [17, 18]. It is hence crucial to diagnose and treat TTTS as early as possible and using the best-proven management strategy. In this chapter, we will mainly discuss its treatment options focusing on fetoscopic laser ablation of anastomoses. We will also discuss the benefits and risks associated with this treatment.
The etiology of TTTS is connected with the architecture of the placenta, and intertwine vascular connections known as anastomoses within the placenta. Actually all MC placentas have anastomoses that connect the fetal circulations. Fortunately, not all MC twins develop TTTS. Three main types of anastomoses might be distinguished: venovenous (VV), arterioarterial (AA), and arteriovenous (AV). The imbalance of blood flow through the placental anastomoses leads to volume depletion in the donor twin, with oliguria and oligohydramnios, and to volume overload in the recipient twin, with polyuria and polyhydramnios. There also appear to be additional factors beyond placental morphology, such as complex interactions of the renin-angiotensin system in the twins involved in the development of this disorder. There are no randomized trials to evaluate the effectiveness of antenatal monitoring or pregnancies complicated by TTTS. Weekly monitoring of the umbilical artery Doppler flow and MVP of amniotic fluid of each fetus may be considered. The evidence for effectiveness of serial (eg, weekly or twice/wk) nonstress tests, biophysical profiles, and other antenatal testing modalities is insufficient to make a recommendation, but these tests can be considered. The management options described for TTTS include expectant management, amnioreduction, intentional septostomy of the intervening membrane, fetoscopic laser photocoagulation of placental anastomoses, and selective reduction. There are no clinical trials regarding optimal timing of delivery for TTTS pregnancies. This depends on several factors, including disease stage and severity, progression, effect of interventions, and results of antenatal testing. Recommendations regarding timing of delivery with TTTS vary, with some endorsing planned preterm delivery as early as 32-34 weeks, and others individualizing care and allowing gestation to progress to 34-37 weeks, particularly in cases of mild disease (eg. stages I and II) with reassuring surveillance.
Twin-to-twin transfusion syndrome (TTTS) is a complication of monochorionic twin pregnancies associated with high perinatal mortality and morbidity. Placental vascular anastomoses, almost invariably present in monochorionic placentas, are the essential anatomical substrate for the development of TTTS. According to recent studies, different pathophysiologic mechanisms may play a role. Diagnosis of TTTS is no longer based on neonatal criteria such as birth weight discordance and hemoglobin difference, but on strict prenatal ultrasound criteria. A significant evolution in prenatal care strategies and management options for patients with TTTS has occurred during the last decade. Endoscopic laser ablation of communicating placental vessels is a new treatment modality that has led to an increase in survival rates. In perinatology, a decrease in mortality rates may be associated with an increase in morbidity rates. Follow-up studies in infants with TTTS are shedding more light on the wide range of morbidity associated with TTTS, such as neurological, cardiac and renal sequelae. This review analyzes the possible pathophysiologic mechanisms involved, discusses the latest findings in diagnosis, therapy and prognosis, and focuses on neonatal and pediatric morbidity associated with TTTS.
Objective To assess the clinical effectiveness of endoscopic laser coagulation of placental vessels in the
Design Prospective study.
Setting Three referral centres for the management of twin-to-twin transfusion syndrome.
Population One hundred and thirty-two pregnancies complicated by severe twin-to-twin transfusion syndrome, reflected by polyhydramnios and enlarged bladder of one twin and oligoanhydramnios and collapsed bladder of the other twin, presenting before 28 weeks of gestation.
Methods Prospective collection of data on pre-procedure assessment, the procedure and the follow up were collected prospectively. Laser coagulation of placental vessels crossing the intertwine membrane on the chorionic surface under sono-endoscopic guidance, followed by amniodrainage.
Main outcome measures Maternal and pregnancy complications, perinatal death and morbidity were assessed over the last five years with follow up of survivors.
Results Endoscopic laser was carried out at a median gestation of 21 weeks. The total number of surviving infants was 144 (55%) and there was at least one survivor in 97 cases (73%). At a minimum age of one year neurological handicap was suspected in six survivors (4.2%).
Conclusions The results of this multicentre study are similar to those in our original report on the first 45 cases. In comparison with serial amniodrainage, the survival rate may be similar, but the handicap rate in survivors appears much lower. This study stresses the need for a prospective study comparing treatment of severe transfusion syndrome threse two techniques.
Twin reversed-arterial-perfusion sequence is a serious complication of monozygotic multiple gestations, affecting 1 percent of monozygotic twins, or 1 in 35,000 births1. It has been hypothesized that in the presence of artery-to-artery and vein-to-vein anastomoses in a monozygotic placenta, blood is perfused by the hemodynamically advantaged twin (“pump” twin) to the other twin (“recipient” twin) by means of retrograde flow2. Inadequate perfusion of the recipient twin is responsible for the development of a characteristic and invariably lethal set of anomalies, including acardia and acephalus. Typically, the pump twin is structurally normal, but it is at risk for in . . .
Although cerebral palsy (CP) is the most common cause of motor deficiency in young children, it occurs in only a to 3 per 1000 live births. In order to monitor prevalence rates, especially within subgroups (birthweight, clinical type), it is necessary to study large populations. A network of GP surveys and registers was formed in 14 centres in eight countries across Europe. Differences in prevalence rates of GP in the centres prior to any work on harmonization of data are reported. The subsequent process to standardize the definition of CP, inclusion/exclusion criteria, classification, and description of children with CP is outlined. The consensus that was reached on these issues will make it possible to monitor trends in CP rate, to provide a framework for collaborative research, and a basis for services planning among European countries.
An acardiac is a gravely malformed foetus, with no functional heart, whose blood supply is maintained by the other, normally developed, twin. The double work load often severely compromises the cardiac function of the normal foetus, called the pump twin. In four pregnancies in women aged 28, 32, 32 and 37 years respectively, the acardiac's cord blood flow was interrupted by minimally invasive laparoscopic foetal surgery. In the first two cases, treated before 20 weeks gestation, the intervention was performed electively using endoscopic-guided laser coagulation. In the other two other cases, at 23 and 28 weeks, the intervention was performed because of signs of cardiac decompensation in the pump twin, and ultrasound-guided bipolar forcipal coagulation was used. The first and the fourth pregnancies ended with term birth of a healthy neonate. The two other pregnancies ended with foetal death, probably caused by entanglement of the acardiac's cord with that of the pump twin. In monoamniotic pregnancies, but also in some diamniotic cases with anhydramnios in the acardiac's sac and close proximity of the cord insertions, cord entanglement is an important threat to the pump twin. Cutting the acardiac's cord after arresting its blood flow may be life-saving to the pump twin in such cases.
One of the major concepts espoused in this volume is that placental form can be as important to the outcome of a twin conception as the genetic derivation of the conceptuses. The most clear-cut evidence for this concept is in monochorionic monozygotic twinning. Except for genetic considerations, monozygotic twins with dichorionic placentas have similar developmental and gestational risks as dizygotic twins. Monochorionic monozygotic twins, however, have two additional potential sources of problems—vascular anastomoses between the fetuses and/or abnormalities of duplication.1, 2 The consequences of aberrations of monochorionic twinning may be a pair of remarkably different so-called identical twins—an argument for avoiding the term as it is not only inaccurate but potentially confusing when counseling affected families. Some of the most bizarre anomalies of human reproduction are seen in these cases—as Antonio asks of Sebastian “How have you made division of yourself?” (Shakespeare, Twelfth Night, V, i).
As we learn more about the human genome and develop more sophisticated ways of studying diseases, disorders, and disturbed development, the borders between these abnormalities become harder to define. For example, as we learn more about the underlying biochemical defects in dwarfing syndromes such as thanatophoric dysplasia, this “malformation” becomes more like an inborn error of metabolism—a genetic defect or alteration with a specifically altered or absent product, leading to a predictable set of consequences depending on the role of that product. Considering this concept, it is perhaps somewhat artificial to discuss developmental/morphologic/structural anomalies separate from the sorts of diseases and disorders reviewed in Chapter 6. However, we are still a long way from defining the underlying molecular mechanisms in most structural variations from “normal,” so there is probably more we can learn from reviewing them in a broader context. Careful analysis of patterns of malformations and associated epidemiologic characteristics may help define where the basic defect could be looked for, and examinations of malformations in twins may provide particularly useful data.
OBJECTIVE: Monoamniotic twin gestations with a non-viable fetus represent an inordinately high therapeutic challenge. Cord entanglement or spontaneous fetal demise of one of the fetuses may result in loss of the pregnancy Since vascular communications are present in virtually all cases, KCI selective feticide cannot he performed, and other intravascular methods are unreliable. We report our experience with ligation and transection of the umbilical cord (L&T U-C) to manage these patients. STUDY DESIGN: Four patients with pre-viable monoamniotic twin gestations in which one fetus was considered non-viable were assessed. L&T U-C was offered if the abnormal twin was non-viable or if cord entanglement with obvious hemodynamic compromise of one of the fetuses was present. A normal karyotype was required. Percutaneous L&T U-C was performed under general anesthesia with combined endoscopic and sonographic guidance using 2-3 mm custom-designed ports. Perioperative intravenous tocolysis and antibiotics were given. RESULTS: The mean gestational age at the time of the procedure was 17.5 weeks (range 16-19). Two patients had an acardiac twin with a normal co-twin, 1 patient had a discordant twin with cystic hygroma and dysplastic kidneys, and 1 patient had cord entanglement with pericardial effusion and evidence of hemodynamic decompensation of one of the fetuses by pulsed Doppler. L&T U-C was successfully performed in all cases. When possible, two knots were placed around the umbilical cord, and the transection was performed between the sutures; otherwise, the cord was transected proximal to the anomalous fetus. Post-operative disentanglement of the umbilical cords was documented with ultrasound. The average time gained after L&T U-C was 17 weeks (range 11-21), and all patients delivered after 30 weeks. Premature rupture of membranes (PROM) within three weeks of the procedure occurred in 1/4 (25%) cases, but was sealed with a percutaneous amniopatch and the pregnancy progressed to term. Two patients (50%) were electively delivered at term. One patient developed oligohydramnios and placental insufficiency at 30 weeks, and the other delivered prematurely at 34 weeks. Neonatal outcomes were unremarkable. CONCLUSIONS: L&T U-C is a reliable technique for the management of complicated monoamniotic twin gestations. Transection of the cord effectively avoids the possibility of cord entanglement and subsequent death of the remaining twin. L&T U-C may also be used prior to spontaneous death of a non-viable twin to prevent neurologic and other complications in the survivor. L&T U-C probably should not be offered to otherwise uncomplicated monoamniotic twins. Transection of the umbilical cord may also improve the outcome of complicated diamniotic monochorionic gestations in which the dividing membrane has been breached during ligation of the umbilical cord.
The twin-twin transfusion syndrome is a serious complication of monochorionic twin pregnancies. Partly as a result of an inadequate understanding of the pathophysiology of the syndrome, there is a lack of consensus in clinical management. We sought to review the available information on the etiology of twin-twin transfusion syndrome, to identify parameters that contribute to the severity of the syndrome, and propose a rational management plan based on pathophysiology, clinical presentation and the efficacy of therapies. We therefore amalgamated recent advances in twin-twin transfusion syndrome computer modelling and clinical studies, particularly on therapeutic outcomes. We found that the oligo-polyhydramnios sequence that defines twin-twin transfusion syndrome prenatally represents a wide continuum of severity in the imbalance between the fetoplacental circulations of both twins. In severe twin-twin transfusion syndrome cases, in which the circulatory imbalance deteriorates beyond fetal control, fetoscopic laser therapy of all anastomoses along the placental vascular equator is predicted to have significantly better survival rates and fewer neurological sequelae than amnioreduction. In contrast, mild twin-twin transfusion syndrome cases have better outcomes after one or at most a few amnioreductions than laser therapy, as a result of significantly fewer procedure-related risks. In conclusion, optimal individual therapy may possibly achieve an 85% survival rate in twin-twin transfusion syndrome, but requires advancement in non-invasive criteria that predict the severity of the syndrome. Identifying such criteria is a future challenge. For the interim, twin-twin transfusion syndrome diagnosed before 26 weeks' gestation has significantly better survival rates and fewer neurological sequelae after laser therapy than amnioreduction. Twin-twin transfusion syndrome diagnosed after 26 weeks can best be treated by amnioreduction, or delivery. Contrary to previous claims, fetoscopic laser therapy has outgrown its experimental status. Although improvements in technique and technology are likely, laser placental ablation has a firm scientific and clinical basis.
Monochorionic monozygotic twins frequently suffer complications from the presence of vascular anastomoses in their monochorionic placentas. Also, sharing of perfusion zones may be unequal, leading to marked growth discordance.This paper analyzes four measures of perinatal outcome (gestational age at delivery, perinatal mortality, birth weight discordance, and presence/absence of hydramnios) according to the vascular patterns of the monochorionic placentas. The worst clinical outcomes were associated with arteriovenous anastomoses in the absence of arterio-arterial and veno-venous anastomoses.The vascular patterns of monochorionic placentas cause significant fetal environmental differences within pairs of monochorionic monozygotic twins. These differences may cause life-long discordance for several phenotypic traits that are not genetically based, and which cause monochorionic monozygotic twins to be “non-identical.” © 1996 Wiley-Liss, Inc.
Background and ObjectivesTo describe laparoscopic management of adnexal mass during pregnancy between January 1994 and November 2003 and give an overview of existing literature on this subject (1992–2003).DesignObservational (descriptive) study with prospectively collected database supplemented by retrospective chart review.SettingTertiary-care referral centre.SubjectsEleven consecutive pregnant patients with an adnexal mass.InterventionsTen patients had laparoscopy with the open entry technique and one with the closed entry technique.Main outcome measuresBlood loss, operating time, number of conversions to laparotomy, complications and pregnancy outcome.ResultsThe incidence of laparoscopic management of adnexal pathology during pregnancy in our institution was 1:1,206 pregnancies (0.1%). One patient was suspected to have an ovarian malignancy, which appeared to be a large malignant tumour originating from the intestine. Ovarian malignancy was not found. In seven cases, surgery was postponed until the 16th week of gestation; however, four patients required surgery earlier in pregnancy due to suspicion of ovarian malignancy (n=1) or adnexal torsion (n=3). No entry-related or intra-operative complications occurred. Two procedures were converted to laparotomy but were not due to laparoscopic complications. One intra-uterine foetal death occurred at 24 weeks of gestation (12 weeks after adnexal detorsion). No postoperative maternal complications occurred, and nine healthy infants were born. One patient continues to have an uncomplicated pregnancy.ConclusionsAdnexal masses requiring surgical intervention can be explored laparoscopically. We advise the open entry technique in order to avoid entry-related complications, e.g. to the pregnant womans uterus and the adnexal mass.
Of all monochorionic twin pregnancies 10-15% are complicated by severe second trimester twin-twin transfusion syndrome (tts). Prognosis of untreated tts is very poor. Fetoscopic laser coagulation of the vascular anastomoses along the vascular equator on the placental surface is a causal treatment for tts and was developed in 1990. Since August 2000, this therapy is available in the Netherlands, at the Leiden University Medical Centre. Between August 2000 and January 2003, we treated 82 patients with severe second trimester tts with fetoscopic laser coagulation of vascular anastomoses. Median gestational age was 20 weeks at laser treatment and 33 weeks at birth. Perinatal survival rate was 70% (114/164). Diagnosis and treatment in the early Quintero-stages resulted in significantly higher perinatal survival. The treatment resulted in at least one survivor in 83% of the pregnancies. These results are similar to those in specialised foreign centres.
By the use of the corrosion technique vascular communications between the fetal vascular beds were studied in 22 dichorionic diamniotic and 23 monochorionic diamniotic placentas.The following observations were made: 1.1. Vascular anastomoses were demonstrated in 20 monochorionic diamniotic placentas.2.2. Not in all of these cases superficial arterio-arterial were present, nor did each placenta show deep arteriovenous anastomoses.3.3. None of the placentas contained more than three cotyledons shared by both twins.4.4. Six main types of vascular communications were found; these appeared in twelve different combinations.5.5. The vascular connection in shared cotyledons is by way of the villous capillaries and the paravascular capillary network.6.6. Evidence of the twin transfusion syndromes was present in three cases of twins with monochorionic diamniotic placentas.
Twin pregnancy has a disproportionate effect on perinatal mortality, being six times higher than for singleton gestations. The major threats to perinatal survival are from two very different pathological processes: spontaneous preterm delivery, and the interlacing clinical complications of monochorionicity. With the realization that perinatal loss/handicap is higher in monochorionic than dichorionic twins, attempts have been made in the last decade to assign chorionicity ultrasonographically, using single or composite parameters, such as number of placental masses, fetal sex, septal thickness and twin peak signs. Such knowledge will allow (a) risk stratification of twin gestations, (b) appropriate selection of prenatal screening and diagnostic methods, (c) vigilant monitoring for early diagnosis of twin-twin transfusion syndrome and growth restriction, and (d) management of preterm labour, congenital malformation, single intra-uterine death and polyhydramnios. By contrast, prospective knowledge of zygosity is unlikely to influence perinatal outcome, since approximately 25 per cent of monozygous conceptions have dichorionic placentation. Postnatal determination of zygosity in like sex twin pairs with dichorionic placenta is important for the future consideration of organ transplantation compatibility and to evaluate the genetic component of various diseases.
In the acardiac, acephalic twin malformation the normal co-twin is put at risk because of the extra cardiac work-load. Surgical procedures may be hazardous to the mother. We describe a novel approach--the insertion of a helical metal coil to induce thrombosis in the umbilical artery of the acardiac twin--which immediately interrupted flow. The co-twin was delivered at 39 weeks and his neonatal course has been normal.
Intrauterine death of one twin in monochorionic pregnancies is associated with increased mortality and morbidity for the survivor. This has been attributed to the consequences of intrauterine disseminated intravascular coagulation (DIC) initiated by the dead twin. We describe a case in which the fetal cerebral and renal lesions typically found in survivors occurred without any derangement in coagulation. Instead, acute twin-twin transfusion was suggested by the presence of severe anemia in the surviving fetus at delivery. We suggest that the lesions frequently found in the survivors are often due to acute hemodynamic and ischemic changes resulting from acute twin-twin transfusion at the time of intrauterine death, rather than to late-onset DIC. This hypothesis has an important implication for future management: Intervention must occur before intrauterine death if neurologic sequelae in the survivor are to be prevented.
Necrosis of the cerebral white matter may be identified in living infants with echoencephalography. Echoencephalographic studies were performed in 89 twins and 12 triplets at less than 36 weeks of gestation to determine the incidence and complications associated with antenatal necrosis of the cerebral white matter. Antenatal necrosis of the cerebral white matter was identified when brain atrophy or cavities in the white matter were present by day 3 of life. Fourteen infants (13.8%) were considered to have antenatal necrosis of the cerebral white matter. The incidence of antenatal necrosis of the cerebral white matter was higher in monochorionic than in dichorionic infants (30% vs 3.3%; p less than 0.001). Univariate analysis showed that antenatal necrosis of the cerebral white matter was significantly associated with polyhydramnios, intrauterine fetal death of the cotwin, hydrops, multiple placental vascular connections, and placental artery-to-artery, vein-to-vein, and artery-to-vein anastomosis. Logistic regression analysis showed that antenatal necrosis of the cerebral white matter was predicted by the presence of either artery-to-artery or vein-to-vein anastomosis and by intrauterine fetal death of a cotwin. Vein-to-vein anastomosis had the strongest association, because 89% of seven infants with vein-to-vein anastomosis demonstrated antenatal necrosis of the cerebral white matter (p = 0.003). Monochorionic multiple gestations frequently are complicated by antenatal necrosis of the cerebral white matter. Multiple vascular connections with vein-to-vein anastomosis appear as the most important associated factor for antenatal necrosis of the cerebral white matter in this population.
Twin-twin transfusion syndrome associated with acute polyhydramnios in one sac and severe oligohydramnios in the other, which characteristically is diagnosed between 18 and 28 weeks, is associated with a high mortality rate for the involved twins. Patients who are managed without intervention have essentially 100% perinatal mortality. Nineteen patients with this diagnosis were treated at Good Samaritan Medical Center over a 5-year period. Because of the known perinatal mortality and because of early experiences with the twin-twin transfusion syndrome, we began to actively intervene in such patients with various modes of therapy. As experience was gained, it was found that repeated therapeutic amniocenteses, if performed before severe maternal abdominal distention or labor, appears to be beneficial.
Most pregnancies with severe twin-twin transfusion syndrome before 27 weeks' gestation result in perinatal death. Previous attempts at therapy have been generally unsatisfactory and rarely successful. We have developed a technique for intrauterine ablation of the vascular communications between the fetoplacental circulations with a fetoscopically directed neodymium:YAG laser. The operation was performed on three women at risk for pregnancy loss from acute hydramnios at 18.5, 22, and 22.5 weeks' gestation. The first two procedures were uneventful, but the third was complicated by a placental vessel perforation. The first two patients delivered at 27 and 34 weeks after premature rupture of membranes and spontaneous labor, whereas the third woman developed severe preeclampsia at 29 weeks which necessitated delivery. Four of the six infants survived. Clinical and ultrasonographic evidence, as well as pathologic examination of the placentas, suggested that stabilization or resolution of the syndrome was due to photocoagulation of the vascular communications. This initial experience suggests that fetoscopic laser occlusion of placental vessels is feasible and superior to previous therapies because it treats the underlying pathophysiology directly.
The "stuck twin" phenomenon in monochorionic diamniotic (MCDA) pregnancies is characterized by marked disparity in both fluid volume and fetal size between the twin gestations. To determine the prevalence, sonographic characteristics, and clinical outcome of this phenomenon, discharge summaries, placental pathologic reports, and prenatal sonograms from 307 twin pregnancies were reviewed. Of 52 cases of MCDA pregnancies, 18 (35%) demonstrated marked disparity in amniotic fluid volume. In 16 of these 18 cases there was discordant twin growth, further suggesting the diagnosis of twin transfusion syndrome. All 16 cases and an additional nine cases supplied by another center demonstrated a small, morphologically normal fetus in an oligohydramniotic sac suspended anteriorly (72%) or laterally (28%) in the uterus. The amniotic membrane separating this twin from the larger twin in the polyhydramniotic sac was thin, closely applied to the smaller fetus, and difficult to detect. Perinatal morbidity was 100% for all twin pairs, and premature labor occurred in all cases. Perinatal mortality ranged from 88% for the larger/poly twin to 96% for the small/oligo twin.
Serial measurements of fetal bladder volume were obtained by real-time ultrasonography at 2- to 5-minute intervals, and the hourly fetal urine production rate was calculated. The mean hourly fetal urine production rate increased from 5 ml/hr at 20 weeks' gestation to 51 ml/hr at 40 weeks. These values are double those reported in previous studies that measured fetal bladder volumes at 15- to 30-minute intervals because the cycle length is shorter than previously thought.
We studied a life-saving method for the unaffected twin in two recent patients who had acardiac monster in twin pregnancy. We succeeded in blocking the umbilical blood flow of the acardiac monster in utero as radical treatment for this abnormality in one of the patients. In case 1, tocolysis and amniocentesis with puncture to the cyst of the acardiac monster were performed to prevent premature labor. However, the patient underwent premature labor at 27 weeks of gestation, and the newborn died. In case 2, fetal treatment was given: A steel coil was placed in the umbilical cord close to the abdominal wall of the acardiac monster under ultrasonographic guidance at 23 weeks of gestation to block blood flow. As a result, no enlargement of the acardiac monster was observed, and the cardiac function of the unaffected fetus improved. At 38 weeks of gestation, the patient delivered a normal baby weighing 2,237g and an acardiac monster weighing 110g. There were no complications in either the mother or newborn. There has been no report describing blockage of the umbilical blood flow of an acardiac monster in utero. Our method is considered efficient and less risky to the mother and the unaffected twin.
One hundred seventy-eight consecutive twin pregnancies were studied to reevaluate the standard diagnostic criteria for chronic twin-to-twin transfusion syndrome of an intertwin hemoglobin difference greater than 5 gm/dl and a birth weight difference greater than 20%. Hemoglobin differences greater than 5 gm/dl were found in six pregnancies with monochorionic placentas but also in seven with dichorionic placentas. Birth weight differences greater than 20% occurred no more commonly in monochorionic than in dichorionic pregnancies. Of the four pregnancies with a coexisting hemoglobin difference greater than 5 gm/dl and birth weight difference greater than 20%, only one had a monochorionic placenta and therefore likelihood of vascular anastomoses. Diagnosis of twin-to-twin transfusion syndrome cannot be definitively established by current standard diagnostic criteria.
A pregnancy complicated by twin transfusion syndrome is presented. When signs of cardiac failure (edema, ascites and hydramnios) persisted in the recipient twin, maternal digoxin therapy was instituted at 27 weeks' gestation. The signs of failure resolved, and the twins were delivered electively by cesarean section at 34 weeks. At birth, the syndrome was confirmed by examination of the infants and placenta. Both infants survived. Digoxin therapy is recommended for fetal heart failure from circulatory overload in twin transfusion.
Vascular communication between placental vessels can occur when there is a fused placental mass in twin gestation. The presence of anastomotic channels can lead to the twin-twin transfusion syndrome in the fetuses. A study was conducted on 278 twin pairs to determine the incidence of vascular communication in fused twin placentas and the frequency of twin-twin transfusion syndrome. Anastomotic communication was found almost universally in monochorionic placentation and very rarely with dichorionic placentas. Twin-twin transfusion syndrome occurred uncommonly despite the high frequency of occurrence of cross-placental vascular communication. Misdiagnosis of intrauterine growth retardation in one twin can be avoided by determination of chorionicity by inspection of the placentas of twin gestation.
The evaluation of 2 cases of twin transfusion syndrome by conventional and real-time B-scan ultrasound is described. The importance of differentiating this syndrome from the isolated growth failure of 1 fetus in a twin pregnancy with a normally developing second fetus is emphasized. Assessment of placentation, fetal size and activity, as well as amount of fluid by diagnostic ultrasound is an important aid in the management of multiple gestation. © 1981 The American College of Obstetricians and Gynecologists.
To assess accuracy of detecting cord entanglement in monoamniotic twins, and to describe perinatal outcomes with aggressive obstetric management.
Seven nonconjoined monoamniotic twin pregnancies and one pseudomonoamniotic twin pregnancy were diagnosed sonographically and evaluated with serial scans and cardiotocography. In the absence of other indications, patients were delivered by elective cesarean on demonstration of lung maturity at or beyond 32 weeks' gestation.
Cord entanglement was diagnosed correctly in four pregnancies, missed in one, and excluded correctly in three. Four pregnancies were delivered after demonstration of pulmonary maturity, three because of premature rupture of membranes or uncontrollable preterm labor, and one because of fetal heart rate abnormality during tocolysis for preterm labor. The mean gestational age at delivery was 33.2 +/- 1.6 weeks, with birth weight 2011 +/- 262 g; all neonates were live-born. Newborn stays averaged 12.0 +/- 5.8 days for the eight neonates delivered electively.
Monoamniotic twin pregnancies and cord entanglement in such twins were diagnosed reliably by ultrasound. Abnormal tracings prompting cesarean delivery occurred in two of the five pregnancies with cord entanglement. Amniocentesis reflected pulmonary maturity of both twins in all pregnancies so assessed, and delivery after 32 weeks' gestation, with lung maturity, resulted in good perinatal outcomes. Statistical validity of these findings is limited by our small sample size.
Twin reversed arterial perfusion sequence is a rare complication of monochorionic twinning, in which the normal pump twin perfuses the abnormal acardiac twin in a reversed fashion via an artery-to-artery placental anastomosis. Mortality in the normal twin exceeds 50% as a result of preterm labor, polyhydramnios, and congestive heart failure.
A twin pregnancy complicated by the twin reversed arterial perfusion sequence developed early hemodynamic decompensation in the pump twin with increasing size of the acardiac twin. Ablation of the acardiac twin at 23 weeks' gestation was achieved successfully by injecting 1 mL of absolute alcohol into the intra-abdominal portion of the single umbilical artery.
Direct ultrasound-guided intravascular injection of absolute alcohol is an easy and straightforward technique to occlude circulation to the acardiac twin. This vessel can be identified easily by color Doppler ultrasonography away from the main venous trunk. Selection of this target, rather than occlusion at the level of the umbilical cord, could reduce the risks of cord accidents and inadvertent intravenous injection of the ablative material.
Gangrene of an extremity in a twin pregnancy has been attributed to the release of thromboplastin from a dead fetus or to a combination of polycythemia and anomalous vasculature. It has not been described in a situation where both twins survived.
In a pregnancy complicated by twin-twin transfusion syndrome and managed with repeated amniocenteses, both twins survived. The recipient twin had necrosis of the left lower leg, which had appeared in the antenatal period and was associated with polycythemia, but not anomalous vasculature.
Antenatally, polycythemia alone may cause necrosis of an extremity. Necrosis could be detected with ultrasound examination and may be an additional argument for laser photocoagulation of the chorioangiopagus.
We undertook a pilot study to determine the feasibility and efficacy of fetoscopic laser occlusion of chorioangiopagous vessels in severe previable twin-twin transfusion syndrome.
A total of 35 patients were referred to the investigators with ultrasonographic findings consistent with twin-twin transfusion syndrome, posterior placental implantation, gestational age < 25 weeks, and clinical hydramnios. Placental vessel occlusion was performed with a rigid 2.9 x 3.85 mm dual-channel fetoscope and neodymium:yttrium-aluminum-garnet laser light.
Of the original 35 patients, 5 were eliminated preoperatively and 4 intraoperatively for various factors. The 26 treated patients had a mean gestational age of 20.8 weeks (range 18 to 24) and a mean fundal height of 36.1 cm (range 29 to 44). One patient has surviving triplets, 8 have surviving twins, 9 have a single survivor (2 neonatal and 7 fetal deaths occurred in this group), and 8 have no survivors (all had pregnancy loss within 3 weeks of treatment). The cases with survivors were delivered for obstetric indications at a mean of 32.2 weeks (range 26 to 37), having gained a mean of 11.7 weeks (range 6 to 17) in utero. Fifty-three percent (28/53) of the fetuses survived with 96% (27/28) developing normally at a mean age of 35.8 months (range 1 to 68). Thirty-three of 35 placentas were monochorionic with chorioangiopagous vessels on gross and microscopic evaluation.
Fetoscopic laser occlusion of chorioangiopagous vessels is technically feasible and improves the course and outcome of severe twin-twin transfusion syndrome in previable fetuses.
In monozygotic twin pregnancies, there are placental vascular communications between the two fetuses. In 15 percent of such pregnancies there is an imbalance in net blood flow between the twins, resulting in the twin-twin transfusion syndrome. The recipient twin may have severe hydramnios during the second trimester of pregnancy, and there is a high risk of perinatal death and cerebral palsy in survivors. This condition can now be treated by endoscopic coagulation of the vascular anastomoses responsible for fetofetal transfusion with a neodymium:yttrium-aluminum-garnet (Nd: YAG) laser.
We performed intrauterine surgery in 45 pregnant women carrying twins at 15 to 28 weeks of gestation (median, 21); in each case there was severe hydramnios in one fetus due to the twin-twin transfusion syndrome. With the use of local anesthesia and continuous ultrasound visualization, a rigid fetoscope 2 mm in diameter, housed in a 2.7-mm cannula, was introduced transabdominally into the amniotic cavity of the recipient twin. A systematic search was made for all vessels approaching or crossing the membrane between the twins, and these were coagulated with an Nd:YAG laser by means of a fiber in the side arm of the cannula.
Coagulation of the communicating vessels was successful in all cases. The total number of fetuses who survived to delivery was 48 (53 percent), and the number of pregnancies with at least 1 survivor was 32 (71 percent). Among the live-born infants, the median gestational age at delivery was 35 weeks (range, 25 to 40), and the median birth weight was 2098 g (range, 550 to 4252). The median interval between the endoscopic laser procedure and delivery was 14 weeks (range, 0 to 21). All the survivors were developing normally at a median age of 12 months (range, 2 to 24).
Our preliminary experience suggests that the twin-twin transfusion syndrome can be treated effectively by endoscopic laser coagulation of the communicating placental vessels.
Twin-twin transfusion syndrome in the midtrimester is associated with a perinatal mortality rate exceeding 80%. Although attributed to intertwin transfusion along vascular anastomoses, these occur in all monochorial placentas, not just the 10% with twin-twin transfusion syndrome. We compared fetoplacental angioarchitecture in monochorionic twin placentas with and without twin-twin transfusion syndrome.
The fetoplacental circulations of both twins in 20 monochorial placentas were perfused immediately after delivery under optimal physiologic conditions and anastomoses delineated by dye-contrast injection. Ten were from pregnancies with evidence of midtrimester twin-twin transfusion syndrome and 10 were from pregnancies without twin-twin transfusion syndrome.
Placentas from pregnancies with twin-twin transfusion syndrome had significantly fewer anastomoses than did those without twin-twin transfusion syndrome, both overall (median one versus six, respectively; p < 0.001) and for each of the different types (arterioarterial, venovenous, and arteriovenous, p < 0.001). Whereas multiple anastomoses were present in all controls, only one twin-twin transfusion syndrome placenta had more than a single communication. Anastomoses in the twin-twin transfusion syndrome group were more likely to be of the deep than the superficial type (80% vs 36% in controls, p < 0.01).
Placental vascular anastomoses in monochorial pregnancies complicated by twin-twin transfusion syndrome are both fewer in number and of a different type than those without twin-twin transfusion syndrome. These differences seem implicated in the underlying pathophysiologic features of twin-twin transfusion syndrome and are of relevance to the development of newer therapies such as placental laser surgery.
Despite advances in maternal fetal medicine, the management of severe twin-to-twin transfusion syndrome in the second trimester presents a significant challenge. Presently, there is no uniformly accepted management protocol that is available for the treatment of this syndrome. We report the use of indomethacin in three cases of severe twin-to-twin transfusion syndrome in the second trimester. In the three cases of severe twin-to-twin transfusion syndrome no reduction of amniotic fluid in either sac was demonstrated. Two cases were complicated by single intrauterine fetal death within 72 hours of initiating indomethacin therapy. Because of our experience with these three cases, we conclude that indomethacin does not prevent perinatal mortality in patients with severe twin-to-twin transfusion syndrome.
To evaluate the prevalence of velamentous cord insertion in twin-twin transfusion using the hypothesis that such insertions may contribute to the etiology of the condition.
All cases of placentas referred for pathologic evaluation at the University of California at San Francisco from 1984-1992 were reviewed for the citation of diamniotic-monochorionic placentation, including the presence of velamentous cord insertions. Maternal and infant records were studied for findings consistent with twin-twin transfusion syndrome.
Thirty-eight cases of monochorionic-diamniotic twins were identified, 11 of which showed twin-twin transfusion syndrome. The prevalence of velamentous cord insertion in the transfusion syndrome subset was 63.6%, compared with 18.5% in those without (significant difference at P < .01). Twin-twin transfusion syndrome pregnancies with velamentous insertions were delivered at a significantly earlier gestational age; they also had fewer surviving infants and were more likely to have been treated prenatally than transfusion syndrome pregnancies without velamentous insertion, although these latter two findings were not significantly different.
Velamentous cord insertions are more common in twin-twin transfusion syndrome pregnancies and may contribute to the development of profound disparity in fluid volume because the membranously inserted cord can be easily compressed, reducing blood flow to one twin. Large-volume amniocentesis may reduce this compressive force on the cord insertion, thus explaining the success of this mode of intervention.
We report on the successful intrauterine surgical treatment of a twin pregnancy with an acardiac fetus. At 18 weeks of gestation the patient presented with polyhydramnios and a hydropic acardius acephalus and the donor twin showed signs of congestive heart failure. Colour Doppler ultrasound allowed localisation of the communicating vessels running on the placental surface towards the umbilicus of the acardiac twin. At 20 weeks we performed endoscopic laser coagulation of the umbilical vessels of the acardiac twin. A sheath (9.8 Charriere) with a 1.9 mm diameter rigid fetoscope (field of vision 60 degrees) was introduced percutaneously under local anesthesia into the amniotic cavity of the "pump" twin. Under sonographic control the fetoscope was directed towards the communicating vessels on the placental surface. A Nd-YAG laser (0.4 mm diameter fiber) was used to coagulate two vessels, artery and vein, until interruption of the reversed arterial perfusion was accomplished. Tricuspid regurgitation of the normal twin disappeared throughout the following two weeks and no further complications occurred throughout pregnancy. At 39 weeks a healthy girl was delivered vaginally. No at the age of 3 months she is developing normally. Minimal invasive endoscopic laser coagulation of the umbilical vessels of the acardiac twin appears to be the optimal currently available treatment for the normal twin, for which otherwise a high mortality ( > 50%) and morbidity must be expected.
The study examines a possible association between increased nuchal translucency thickness at 10-14 weeks of gestation in monochorionic twin pregnancies and the subsequent development of severe twin-to-twin transfusion syndrome (TTS). In 132 monochorionic twin pregnancies, including 16 that developed severe TTS at 15-22 weeks of gestation and 116 that did not develop TTS, crown-rump length, nuchal translucency thickness and fetal heart rate were measured at 10-14 weeks. In those that developed severe TTS, the prevalence of nuchal translucency thickness above the 95th centile of the normal range and the intertwin difference in nuchal translucency thickness and fetal heart rate were significantly higher than in the non-TTS group; there were no significant differences between the groups in the inter-twin difference in crown-rump length. For fetal nuchal translucency above the 95th centile, the positive and negative predictive values for the development of TTS were 38% and 91%, respectively; the likelihood ratios of nuchal translucency above or below the 95th centile for the development of severe TTS were 4.4 (1.8-9.7) and 0.7 (0.4-0.9), respectively. These findings demonstrate that the underlying hemodynamic changes associated with TTS may manifest as increased fetal nuchal translucency thickness at 10-14 weeks of gestation.
In an ultrasound screening study at 10 to 14 weeks of gestation for measurement of fetal nuchal translucency thickness there were 102 monochorionic and 365 dichorionic twin pregnancies. In the monochorionic compared with the dichorionic pregnancies there was a higher rate of fetal loss before 24 weeks of gestation (12.2% versus 1.8%), perinatal mortality (2.8% versus 1.6%), prevalence of delivery before 32 weeks (9.2% versus 5.5%), and prevalence of birthweight below the 5th centile in both twins (7.5% versus 1.7%). However, the proportion of pregnancies with a birthweight discordancy of more than 25% was similar in the two groups (11.3% versus 12.1%).
To investigate cranial ultrasonographic findings in survivors of monochorionic pregnancies complicated by fetofetal transfusion syndrome.
Case details of all monochorionic twin pregnancies complicated by fetofetal transfusion syndrome were obtained from the Centre for Fetal Care database for a 3-year period. Fetofetal transfusion syndrome was diagnosed according to ultrasonographic criteria. Eligible for entry were twin pregnancies resulting in live-born preterm infants and complicated by fetofetal transfusion syndrome severe enough to require amnioreduction. Cranial ultrasonographic scans performed within 48 hours of birth were reviewed for evidence of abnormality.
Seventeen pregnancies were eligible for inclusion in the study. Median gestational age was 25 weeks (between 17 and 29 weeks) at diagnosis and 30 weeks (between 25 and 35 weeks) at delivery. Three infants died before ultrasonography could be performed. The remaining 31 twin infants received an early cranial ultrasonographic scan. One of the 31 had a major cerebral infarct; 10 others had evidence of other, more minor, antenatally acquired lesions.
Both donor and recipient survivors from pregnancies complicated by fetofetal transfusion syndrome are at significant risk for antenatally acquired cerebral lesions. Long-term neurologic follow-up studies are indicated to determine the clinical significance of these lesions.