Operative fetoscopy: new perspective in fetal therapy?

Amnion-Analogous Medical Device for Fetal Membrane Healing: A Preclinical Long-Term Study

Although recent invasive fetal surgeries have improved fetal outcomes, fetal membrane rupture remains a major complication, leading to premature delivery, thus undermining the complete benefits of such procedures. A biocompatible amnion-analogous medical device (AMED) consisting of polycaprolactone framework and decellularized amniotic membrane (dAM)-derived hydrogel for restoration of amniotic membrane defect is developed using 3D printing technology. Its efficacy on healing iatrogenic fetal membrane defects in vitro is evaluated, showing that the dAM gel contains migratory and proliferative properties. The fetoscope feasibility of the developed AMED is assessed using a pregnant swine model. All animals had successfully recovered from anesthesia and the fetoscopic procedure and maintained a healthy condition until the end of the pregnancy. AMED exhibits superior surgical handling characteristics and is easy to manufacture, nonimmunogenic, biocompatible, and suitable for storage and transport for off-the-shelf use; hence, it can be used in successfully sealing defect sites, thus improving the preservation of the amniotic fluid, which in turn improves fetal survival and development.

Connexin 43 is overexpressed in human fetal membrane defects after fetoscopic surgery

OBJECTIVE

We examined whether surgically induced membrane defects elevate connexin 43 (Cx43) expression in the wound edge of the amniotic membrane (AM) and drives structural changes in collagen that affects healing after fetoscopic surgery.

METHOD

Cell morphology and collagen microstructure was investigated by scanning electron microscopy and second harmonic generation in fetal membranes taken from women who underwent fetal surgery. Immunofluoresence and real-time quantitative polymerase chain reaction was used to examine Cx43 expression in control and wound edge AM.

RESULTS

Scanning electron microscopy showed dense, helical patterns of collagen fibrils in the wound edge of the fetal membrane. This arrangement changed in the fibroblast layer with evidence of collagen fibrils that were highly polarised along the wound edge but not in control membranes. Cx43 was increased by 112.9% in wound edge AM compared with controls (p < 0.001), with preferential distribution in the fibroblast layer compared with the epithelial layer (p < 0.01). In wound edge AM, mesenchymal cells had a flattened morphology, and there was evidence of poor epithelial migration across the defect. Cx43 and COX-2 expression was significantly increased in wound edge AM compared with controls (p < 0.001).

CONCLUSION

Overexpression of Cx43 in the AM after fetal surgery induces morphological and structural changes in the collagenous matrix that may interfere with normal healing mechanisms. © 2016 The Authors. Prenatal Diagnosis published by John Wiley & Sons, Ltd.

Congenital asymptomatic diaphragmatic hernias in adults: a case series

INTRODUCTION

Congenital diaphragmatic hernia is a major malformation occasionally found in newborns and babies. Congenital diaphragmatic hernia is defined by the presence of an orifice in the diaphragm, more often to the left and posterolateral, that permits the herniation of abdominal contents into the thorax. The aim of this case series is to provide information on the presentation, diagnosis and outcome of three patients with late-presenting congenital diaphragmatic hernias. The diagnosis of congenital diaphragmatic hernia is based on clinical investigation and is confirmed by plain X-ray films and computed tomography scans.

CASE PRESENTATIONS

In the present report three cases of asymptomatic abdominal viscera herniation within the thorax are described. The first case concerns herniation of some loops of the large intestine into the left hemi-thorax in a 75-year-old Caucasian Italian woman. The second case concerns a rare type of herniation in the right side of the thorax of the right kidney with a part of the liver parenchyma in a 57-year-old Caucasian Italian woman. The third case concerns herniation of the stomach and bowel into the left side of the chest with compression of the left lung in a 32-year-old Caucasian Italian man. This type of hernia may appear later in life, because of concomitant respiratory or gastrointestinal disease, or it may be an incidental finding in asymptomatic adults, such as in the three cases featured here.

CONCLUSIONS

Patients who present with late diaphragmatic hernias complain of a wide variety of symptoms, and diagnosis may be difficult. Additional investigation and research appear necessary to better explain the development and progression of this type of disease.

Tissue engineering a fetal membrane

The aim of this study was to construct an artificial fetal membrane (FM) by combination of human amniotic epithelial stem cells (hAESCs) and a mechanically enhanced collagen scaffold containing encapsulated human amniotic stromal fibroblasts (hASFs). Such a tissue-engineered FM may have the potential to plug structural defects in the amniotic sac after antenatal interventions, or to prevent preterm premature rupture of the FM. The hAESCs and hASFs were isolated from human fetal amniotic membrane (AM). Magnetic cell sorting was used to enrich the hAESCs by positive ATP-binding cassette G2 selection. We investigated the use of a laminin/fibronectin (1:1)-coated compressed collagen gel as a novel scaffold to support the growth of hAESCs. A type I collagen gel was dehydrated to form a material mimicking the mechanical properties and ultra-structure of human AM. hAESCs successfully adhered to and formed a monolayer upon the biomimetic collagen scaffold. The resulting artificial membrane shared a high degree of similarity in cell morphology, protein expression profiles, and structure to normal fetal AM. This study provides the first line of evidence that a compacted collagen gel containing hASFs could adequately support hAESCs adhesion and differentiation to a degree that is comparable to the normal human fetal AM in terms of structure and maintenance of cell phenotype.

Selective reduction and termination of multiple pregnancies

The substantial increase in high order multiple pregnancies in the last two decades as a result of assisted reproductive techniques has necessitated the development of multifetal pregnancy reduction as a management tool to decrease fetal number and improve perinatal survival. The evidence in favour of reduction in pregnancies with more than four fetuses to twins is undisputed. Despite the recent improvements in expectant management of triplets with reasonable perinatal outcomes, the evidence suggests that reduction to twins significantly reduces the risk of preterm delivery without an increase in miscarriage rates. Recent advances in vascular-occlusive techniques have allowed the possibility of selective termination in monochorionic pregnancies in the presence of discordant anomalies or indeed multifetal reduction in non-trichorionic triplets, with radiofrequency ablation and cord occlusion appearing to be the most successful. However, the techniques vary in complexity and complication rates, which increase with gestation. Hence the need to refer these pregnancies early to specialist centres.

Successful diagnostic and therapeutic intrauterine fetal interventions by natural orifice transluminal endoscopic surgery (with videos)

BACKGROUND

Despite advances in the development of fetal surgery, morbidity and mortality are substantial. A natural orifice transluminal endoscopic surgery (NOTES)-guided approach to the gravid uterus may offer a less-invasive technique.

OBJECTIVE

To assess the feasibility of NOTES for diagnostic and therapeutic intrauterine fetal interventions.

SETTING

Survival and nonsurvival experiments on pregnant sheep.

DESIGN AND INTERVENTION

Nonsurvival experiments performed in 2 pregnant sheep (80-110 days' gestation). A third ewe underwent NOTES and survived for 4 weeks. Transgastric (nonsurvival ewes) and transvaginal (1 nonsurvival and the survived ewe) peritoneoscopy was performed after standard needle-knife entry into the peritoneal cavity. Endoscopic access to the gravid uterus was assessed. EUS-guided, transuterine injection of saline solution into the fetal cardiac ventricle and vessels was attempted in all.

MAIN OUTCOME MEASUREMENTS

Feasibility of NOTES- and EUS-guided intervention in a pregnant animal model, visibility of fetal parts via EUS compared with transabdominal US.

RESULTS

Entry into the peritoneal cavity was achieved in each ewe. Access to and complete visualization of the gravid uterus were successful once within the abdominal cavity. Visualization of the fetal parts and the placental cotyledons by EUS was achieved in all animals. EUS-guided amniocenteses and transuterine intracardiac and intravascular injection of saline were successful. There were no complications or preterm delivery after the procedures.

LIMITATIONS

Animal model.

CONCLUSIONS

NOTES is technically feasible in the pregnant ewe. Intraperitoneal EUS via a NOTES approach provides excellent access and visualization of the intrauterine cavity and fetal parts.

[Fetoscopic tracheal occlusion for the treatment of severe congenital diaphragmatic hernia: preliminary results]

OBJECTIVES

To evaluate survival and lung growth in fetuses with severe congenital diaphragmatic hernia (CDH) treated with fetoscopic tracheal occlusion (FETO) compared with control fetuses and to analyze possible complications of the anesthetic techniques used.

PATIENTS AND METHODS

This prospective study was performed on fetuses with CDH. FETO was undertaken before the 29th week of gestation on fetuses with a lung-to-head ratio (LHR) less than 1. FETO was not performed on fetuses with an LHR between 1.0 and 1.5 or those with an LHR less than 1 where consent was not given. Lung growth was monitored by means of LHR. FETO was performed under fetal intramuscular anesthesia and maternal epidural anesthesia and sedation with remifentanil.

RESULTS

Seventeen fetuses were included in the study. FETO was performed on 11 fetuses and was effective in 9. The median percentage difference between LHR at diagnosis and prior to FETO was 1.15% (P=.183); between diagnosis and before removing the balloon, the difference was 130.5% (P=.003); and between diagnosis and before delivery, 90.18% (P=.003). In the control group (n=6), the median percentage difference between LHR at diagnosis and before delivery was 49.25% (P=.028). No significant hemodynamic or respiratory changes occurred in either mother or fetus during fetoscopy. All the fetuses in the control group died; 45.5% of those in the FETO group survived.

CONCLUSIONS

The use of FETO in cases of CDH appears to increase survival and lung growth. Fetal anesthesia in association with maternal epidural anesthesia and sedation makes it possible to place and remove the endotracheal balloon via fetoscopy with acceptable maternal comfort and without notable complications.

Doppler imaging using spectrally-encoded endoscopy

The capability to image tissue motion such as blood flow through an endoscope could have many applications in medicine. Spectrally encoded endoscopy (SEE) is a recently introduced technique that utilizes a single optical fiber and miniature diffractive optics to obtain endoscopic images through small diameter probes. Using spectral-domain interferometry, SEE is furthermore capable of three-dimensional volume imaging at video rates. Here we show that by measuring relative spectral phases, this technology can additionally measure Doppler shifts. Doppler SEE is demonstrated in flowing Intralipid phantoms and vibrating middle ear ossicles.

Endoscopic fetal surgery: in vitro thermic effect of electrosurgical units

OBJECTIVE

The study focused on the safety of electrosurgical devices in endoscopic fetal surgery. The thermic effects of monopolar electric waves were studied in vitro in order to obtain safety indications in terms of mode of intramniotic application of electrical devices (time and number of shots; volts; and distance from tissues to be preserved).

STUDY DESIGN

A glass model filled with saline solution, and an electrical device with resistor and voltage supply, were constructed to reproduce the physical effects of thermic conductivity in vitro; a Swan-Ganz thermic sensor was used to measure the temperature inside the beuta. Different series of tests were carried out.

RESULTS

The maximal increase (8.60 +/- 0.04 degrees C) takes place at the external surface of the resistor (distance: 0 cm), while at 2 cm, the temperature of the saline solution does not change.

CONCLUSIONS

Our tests demonstrate that in order to avoid any kind of risk during electrosurgical procedures on fetuses, the electrode must be placed at least 0.5 cm from delicate tissues.

Telemetric monitoring of tracheal pressure after tracheal occlusion for treatment of severe congenital diaphragmatic hernia

INTRODUCTION

Prenatal tracheal occlusion using endoscopic techniques obstructs the normal egress of lung fluid during pulmonary development and stimulates lung growth in cases of congenital diaphragmatic hernia (CDH). Although FETO might be an effective strategy for treatment of CDH, the mechanism especially due to the supposed increasing transpulmonary pressure is unknown.

OBJECTIVE

The purpose of this study was to monitor the pressure below the attached balloon in the fetal lamb telemetrically.

METHODS

Four time-dated pregnant Merino ewes underwent fetal and maternal surgery. A special prepared silicone catheter was placed below the epiglottis by laryngoscopy on day 110 or 140 of gestation. The tracheal pressure below the fixed catheter could be monitored telemetrically using the Data Sciences TA11-PA-C40 pressure device. Hundred and twenty measurement points were recorded over a period of 2 min.

RESULTS

A maximum of lung pressure rate was found immediately after implantation (23.7 +/- 4.6 mm Hg). During the first hour, the pressure decreased to an average value of 16.9 mmHg. About 70 h after the block, this value decreased to a minimum level of 8.3 +/- 0.4 mmHg.

CONCLUSION

Decreasing pressure variation might indicate that lung growth has stopped and that the ideal point of time to remove the balloon is achieved. Increasing pressure has to be related to the morphometric analysis of the lung's structural development and maturation, comparing the efficacy of FETO in preventing or reversing pulmonary hypoplasia. Further investigation of continuous telemetric monitoring of tracheal pressure in the fetal lamb is required.

Ultrasound-guided injection and occlusion of the trachea in fetal sheep

OBJECTIVES

To access the fetal sheep trachea by ultrasound-guided transthoracic injection in order to deliver gene therapy vectors or occlude the trachea with a detachable balloon.

METHODS

Fetal sheep were operated on at a mean gestational age of 102 (range, 81-116) days (term = 145 days). Under ultrasound guidance, either a 20-G spinal (for vector delivery) or a 16-G Kellett (for placement of an occlusive balloon) needle was inserted via the fetal thorax into the fetal trachea.

RESULTS

Using the 20-G spinal needle the trachea was accessed successfully in 33/36 fetuses, with 97% survival. Failure to inject was related to fetal position and gestational age. Blood vessel damage causing significant morbidity occurred in two fetuses (6%). Tracheal occlusion was achieved by puncturing the trachea with the 16-G needle and advancing an endoluminal balloon in three out of five attempts in a mean time of 17 (range, 16-19) min, with 100% survival. In one case, the balloon became sited within the accessory lobe bronchus and was not inflated. At postmortem examination 21 days later, all balloons remained inflated and occluded the trachea, and the lung-to-body weight ratio and airways morphometric indices were consistent with relative pulmonary hyperplasia in the obstructed lungs.

CONCLUSIONS

Ultrasound-guided transthoracic tracheal puncture is a reliable technique in fetal sheep, with low morbidity and mortality. Using this technique, a detachable endotracheal balloon can be placed to provoke pulmonary growth. Advances in needle design and balloon size may improve the success rate.

Management of other complications specific to monochorionic twin pregnancies

Monochorionic (MC) twins have a 3-10-fold higher perinatal mortality and morbidity than dichorionic twins. This is largely attributable to their common vascular architecture and the high rate of discordant fetal growth, growth restriction and congenital abnormalities. In the event of a single intrauterine death (IUD), intertwin agonal transfusion results in up to a 38% risk of death and a 46% risk of neurological injury to the co-twin. This chapter addresses the management of complications unique to MC twins. The primary aim of management is to prevent single IUD or, if inevitable, prevent agonal transfusion occurring by vascular occlusive selective feticide. Older fetoscopic techniques have been replaced by the simpler ultrasound-guided techniques of interstitial laser and bipolar cord occlusion. Their application in twin reversed-arterial perfusion sequence has been associated with a 50% reduction of perinatal mortality in the pump twin. Moreover, prophylactic interstitial laser therapy in early pregnancy might obviate the technical and clinical difficulties in the presence of fetal decompensation in later pregnancy. Recent strategies to reduce the high perinatal mortality due to cord entanglement in antenatally diagnosed monoamniotic twins including medical amnioreduction and elective caesarean delivery at 32 weeks, are also discussed.

Tératomes sacrococcygiens. Y a-t-il une place pour le traitement in utero des formes compliquées ? À propos de trois cas

The majority of sacrococcygeal teratomas diagnosed before birth can be managed by planned delivery and postnatal surgery. However, large tumors early in gestation may result in placentomegaly, hydrops and fetal death and a preeclampsia-like syndrome in the mother. This is due to high output cardiac failure in the fetus caused by arteriovenous shunting through the tumor. In these cases, in utero treatment may offer improved chances of survival, and emerging technologies should lower fetal and maternal morbidity. Nevertheless, these therapeutics need to be correctly evaluated.

Minimal-access fetal surgery for twin-to-twin transfusion syndrome

BACKGROUND

Laser ablation of placental vessels effectively halts severe twin-to-twin transfusion syndrome (TTTS), but fetal surgery remains a dangerous approach. The authors present the technical aspects of endoscopic fetal surgery in their initial clinical experience.

METHODS

Altogether, 11 women underwent endoscopic fetal surgery for severe TTTS. Access to the recipient's sac was obtained by the Seldinger technique via minilaparotomy. A 12-Fr peel-away introducer was used as a cannula to accommodate a custom-curved 9-Fr sheath containing a 1.9-mm semirigid fiber endoscope. Laser ablation was performed on all unpaired vessels crossing the intertwin membrane using a 400- micro m neodymium: yttrium-aluminum-garnet (Nd: YAG) fiber. The cannula was removed over a gelatin sponge plug.

RESULTS

The median operating time was 65 min (range, 45-105 min). No patient experienced amniotic leak postoperatively. The length of hospital stay was 2.8 +/- 1.6 days. Immediate improvement of the TTTS was noted in all but two patients. Pneumonia developed, in one mother leading to premature labor. There were no other major surgical complications. Fetal survival at 2 weeks was 73%.

CONCLUSIONS

The safety and efficacy of endoscopic fetal surgery for severe TTTS can be optimized with the application of current minimal-access techniques. The superiority of this approach over less invasive means is still being evaluated through prospective studies.

Prenatal intervention: ethical considerations for life-threatening and non-life-threatening anomalies

Ethical issues in maternal-fetal surgery require special consideration because of the often-conflicting interests of the mother and fetus. Over the past 2 decades an ethical framework for fetal therapy and maternal-fetal surgery has been developed. This framework continues to evolve as new procedures are developed and new controversies arise. The most recent ethical challenge has been the application of maternal-fetal surgery to nonlethal fetal anomalies, specifically, repair of fetal myelomeningocele. Such procedures require early evaluation by randomized clinical trials to avoid premature dissemination of unproven therapy. These trials currently are being initiated, and the ethical framework for proceeding requires careful consideration. This review will summarize the current ethical issues and controversies in maternal-fetal surgery in the context of these new developments.

Endoscopic examination of the fetus in early pregnancy

OBJECTIVE

To assess if fetal examination is feasible by endoscopy in the late first-early second trimester.

SETTING

Tertiary referral center for high risk obstetrics and genetics.

PATIENTS AND METHODS

Patients (total number 9) submitted to pregnancy termination for social reason (7) or for chromosomal abnormality (2) between 10 and 14 weeks of pregnancy. Visualisation of the foetus by a transabdominally introduced endoscope (19 gauge) under local anaesthesia. Step by step examination of the foetal contour and double check of the recordings by a senior Pathologist.

RESULTS

Patients complained no serious discomfort. Visualisation was accomplished in all cases with ease and the images were judged satisfactory by the Pathologist. Fetal examination was found easier at 10-12 weeks of gestation rather than at 13-14 weeks.

DISCUSSION

Endoscopy is a simple and well tolerated procedure, which enables precise visualization of external fetal anatomy as early as the first trimester of gestation. Therefore it can be proposed before surgical termination of pregnancy.

Bipolar coagulation of the umbilical cord in complicated monochorionic twin pregnancy

OBJECTIVES

In monochorionic twin pregnancy in which one twin is a nonviable fetus, selective feticide may be considered. We aimed to occlude the umbilical cord with a bipolar forceps for doing so.

STUDY DESIGN

This was a multicenter experience in 10 consecutive patients either with twin-to-twin transfusion syndrome and one fetus affected by a condition not compatible with normal extrauterine life or with acardiac twinning.

RESULTS

There were no intraoperative problems, and the mean procedure time was 17.5 minutes. The flow was stopped in all 10 cases. Two cases were complicated by rupture of the fetal membranes within 2 days, and the pregnancies were terminated. The other 8 pregnancies resulted in the live birth of a healthy baby. The mean interval between procedure and birth was 15.1 weeks (range, 7-20 weeks). In one patient emergency cesarean delivery for abruptio placentae was done at 26 weeks, 7 weeks after the procedure. The other 7 patients were delivered beyond the 36th week of gestation. All 8 children are alive and well, with a mean follow-up of at least 1 year.

CONCLUSION

Bipolar coagulation is a safe, effective, and simple procedure for cord coagulation that is feasible through a single port and can be performed solely under ultrasonographic guidance.

First trimester prenatal diagnosis: embryoscopy and fetoscopy

Embryoscopy and fetoscopy are techniques that render the developing embryo/fetus and its environment accessible to the "outside" world, which includes diagnosis and, potentially, therapy. Embryocopy and fetoscopy, sometimes referred to as embryofetoscopy, uses high-resolution fiber optic equipment for direct visualization of the embryo/fetus. This has been used to identify developmental milestones from weeks 4 to 8 after conception. With this technique, it has been possible to identify anomalies and confirm those previously diagnosed by ultrasound. Its application has generally included the first and early second trimester of pregnancy for prenatal diagnosis in continuing pregnancies. In addition, fetal blood sampling has also been successfully performed experimentally with this technology, extending its potential applications into the realm of fetal therapy. Future applications for embryofetoscopy include therapeutic interventions such as gene or cell therapy at a time when the embryo is immunologically tolerant. This article focuses on the importance of embryoscopy and fetoscopy (embryofetoscopy) to perinatal medicine and its potential contributions to the concept of fetal therapy.

Closure techniques for fetoscopic access sites in the rabbit at mid-gestation

Operative fetoscopy may be limited by its relatively high associated risk of preterm prelabour rupture of membranes. The objective of this study was to study closure techniques of the access site for fetoscopy in the mid-gestational rabbit. A total of 32 does (288 amniotic sacs) at 22 days gestational age (GA; term = 32 days) underwent 14 gauge needle fetoscopy, by puncture through surgically exposed amnion. Entry site was randomly allocated to four closure technique groups: myometrial suture (n = 14), fibrin sealant (n = 15), autologous maternal blood plug (n = 13), collagen plug (n = 14); 16 sacs were left unclosed (positive controls), and the unmanipulated 216 sacs were negative controls. Membrane integrity, presence of amniotic fluid and fetal lung to body weight ratio (FLBWR) were evaluated at 31 days GA. Following fetoscopy without an attempt to close the membranes, amniotic integrity was restored in 41% of cases (amniotic integrity in controls 94%; P = 0.00001). When the access site was surgically closed, the amnion resealed in 20-44% of cases, but none of the tested techniques was significantly better than the others or than positive controls. Permanent amniotic disruption was associated with a significantly lower FLBWR in all groups. In conclusion, the rate of fetoscopy-induced permanent membrane defects in this model did not improve by using any of the closure techniques tested here.

Twin-twin transfusion syndrome

Twin-twin transfusion syndrome is a complication of monochorionic twin pregnancies associated with extremely high perinatal morbidity and mortality. This article describes the ultrasound features associated with this condition and possible pathophysiological mechanisms. Management options are outlined, including recent development such as laser ablation of placental vascular communications.

The midgestational rabbit as a model for the creation of membrane defects after needle fetoscopy

OBJECTIVES

The aim of the study was to determine whether the pregnant rabbit at mid gestation could be used as a suitable in vivo model for the study of membrane defects after invasive procedures.

STUDY DESIGN

Pregnant rabbits at gestational ages of 22 and 18 days (term is 32 days' gestation) underwent needle insertion with different instrument diameters (1.1 mm, 1.35 mm, 2.0 mm, and 2.7 mm). Two different insertion techniques were evaluated, blind amniotic puncture and puncture through surgically exposed amnion. Membrane integrity, presence of amniotic fluid, and fetal lung/body weight ratio were evaluated at 31 days' gestation.

RESULTS

Among rabbits operated on at 22 days' gestation the amniotic integrity restoration at 31 days' gestation ranged from 46% to 76% in the different diameter and access technique groups, as compared with 98% in untreated sacs (P <.05 for all groups). Fetuses from sacs with persisting membrane defects had oligohydramnios and significantly lower fetal lung/body weight ratios. Survival rates among fetuses operated on at 18 days' gestation were so poor that appropriate statistical analysis was not possible in this group.

CONCLUSIONS

The rabbit at mid gestation can be used as a model to reproduce permanent membrane defects after fetoscopy, reproducing oligohydramnios and pulmonary hypoplasia. This may provide a suitable in vivo model for the study of iatrogenic membrane defects.

Obstetrical endoscopy

Fetoscopy has been reintroduced in fetal diagnosis and therapy, as a result of instrumental innovations. It has been suggested that fetoscopy be used to guide endoscopic operations on the fetus, but this application is still in the experimental phase. Its use for surgical interventions on the placenta, umbilical cord, and to a lesser extent the fetal membranes, could be called 'obstetrical' endoscopy. Nd:YAG laser coagulation of chorionic plate vessels for feto-fetal transfusion syndrome is the most common operation carried out today. Survival rates of 60% or more have recently been reported on both sides of the Atlantic Ocean. Neurological morbidity does not exceed 6%, which compares favorably with serial amnioreductions and may become the most important incentive for performing the operation. A randomized trial comparing both therapies as a next step is being proposed. Fetoscopy has also been used for cord ligation, but because of the complexity of the operation and the high risk for preterm prelabor rupture of the membranes, other alternatives have been investigated. Most experience has been gathered with bipolar cord occlusion, a procedure which can be performed under ultrasound guidance. The instrumental considerations and potential complications of fetoscopy are discussed.

Experience with fetoscopic cord ligation

OBJECTIVE

In the case of a monochorionic multiple pregnancy with one non-viable fetus who compromises its co-twin, fetoscopic cord ligation may be performed. We describe our fetoscopic cord ligation technique and discuss the efficacy of cord ligation for salvaging the co-twin, based on available data.

STUDY DESIGN

Descriptive case series of four cases and review of the cases published up to 1996.

RESULTS

We performed four successful ligations. Of the 23 reported cases, which include the present series, two ligations failed. Four fetuses died in utero, and 17 were born alive at a mean of 8 weeks following the procedure. Two babies died in the perinatal period, a third after 60 days. Preterm uterine contractions do not seem to be a clinical problem. Preterm prelabour rupture of the membranes (PPROM) complicates about 40% of cases, the majority occurring prior to 32 weeks.

CONCLUSION

Fetoscopic cord ligation is a feasible procedure with a 71% survival rate and a high risk for PPROM.

Twin-twin transfusion syndrome: the challenge of etiology-based management decisions

Studies published in the past year have attempted to model the pathophysiology of the twin-twin transfusion syndrome and also to establish the minimal diagnostic criteria for the condition. Many papers focused on treatment regimens and their sequelae. Aggressive treatment with serial amnioreduction continues to predominate, and appears to be more successful than conservative medical management, whereas selective feticide is reserved for cases that fail to respond to amnioreduction. Small series utilizing laser ablation and amniotic septostomy appeared; with laser proponents suggesting that their approach may carry a lower risk of neurological sequelae. Progress in ultrasound and Doppler techniques has begun to yield earlier and better diagnostic approaches which, coupled with an awareness of the possible anastomotic configurations, may allow for the selection of the management protocol most likely to succeed in each individual case.