Introduction Embryoscopy and Fetoscopy Applications Future Directions References


APPLICATIONS

Embryofetoscopy can be utilized to study embryonic development through direct visualization of structures, anomalies and developmental milestones, especially those in aborted embryos as risk of failure is not as catastrophic.  For example, at 6 weeks fetal face can show forehead, widely spaced eyes, oral and nasal cavities and by week 10 the facial features become more prominent.  Development of trunk and limbs, closure of the neural tube by week 9 as well as fully developed hands and feet can also be seen [2].  The embryo itself is very difficult to examine after it has been evacuated due to damage during surgery or spontaneous vaginal exit.  Employing embryofetoscopy before evacuation occurred can thus allow to examine the embryo in its intact condition and thus study developmental defects and causes for death in utero, which can often originate from single gene defects or abnormal karyotypes.  Obtaining this knowledge can further help the parents avoid recurrence of the defects in future pregnancies [1]. 

Embryofetoscopy is also often used with a high degree of confidence as a verification tool for definite diagnosis of genetic disorders and congenital anomalies after high-resolution ultrasonography identified their possibility and detailed morphologic assessment is not possible [3].  Such diseases include Smith-Lemli-Opitz syndrome, van der Woude syndrome, Pierre Robin syndrome or Meckel-Gruber syndrome, just to name a few [1].  Other abnormalities that have been diagnosed with embryofetoscopy are polydactyly, unilateral cleft lip, limb and facial anomalies, ectrodactily, cleft palate, occipital encephalocele, club hands, hypoplasia of forearm, frontal encephalocele, Pierre Robin sequence, cutaneous angioma, clinodactily, facial dysmorphia, Cystic hygroma, Omphalocele, and neural tube defect [4].  Embryofetoscopy image examples of muscle biopsy in suspects of Duchenne’s muscular dystrophy, fetal antegrade cystourethoroscopy for lower urinary tract obstruction, view of constricting amniotic band around upper extremity of a fetus with amniotic band syndrome, view of cord coagulation for TRAP (twin reversal arterial perfusion) sequence, view of chorioangiopagus on a monochorionic placenta in a case of severe TTTS (twin-twin transfusion syndrome) are shown in the next sequence of images [7].  Careful planning of needly entry needs to be performed as only partial view of the fetus is possible as can be seen from these images[3].  Embryofetoscopy can also be used to confirm the normality of  the patient even with high risk of genetic disorders or suspicious results from other imaging techniques [2].

















 Figure 4:  Image 1--Fetoscopic view of muscle biopsy  being performed on a fetus at 18 weeks'gestation;  Image 2--Fetal antegrade cystourethoroscopy.  (Left)  Trabeculated bladder but nondilated ureteral orifice  (arrow).  (Right)  Wire probe verifying presence of  urethral atresia; Image 3--Fetoscopic view of a  constricting amniotic band around the upper extremity of  a fetus with amniotic band syndrom; Image 4--Fetoscopic  view of cord coagulation for TRAP sequence.  (Left)  Umbilical cord being grasped by the bipolar device and  bubbles forming as heat is generated during cord coagulation.  (Right)  Umbilical cord after coagulation (arrow); Image 5--Fetoscopic view of chorioangiopagus on a monochroionic placenta before and after selective fetoscopic laser photocoagulation in a case of severe TTTS.  (Left)  An artery entering a cotyledon and a vein draining the same cotyledon crossing to the opposite twin.  (Right)  Blanched area of the photocoagulated vein.

Moreover, embryofetoscopy can be theoretically used for fetal blood sampling and therapy much earlier than currently existing technologies would allow.  Not having to wait for the 2nd trimester to obtain results about deviant chromosomes can significantly decrease parents’ anxiety and allow the opportunity for early termination if necessary.  Some headway has already been accomplished in this area when Reece et al. [8] obtained a small aliquot of blood by using 3.5-mm fiber-optic endoscope passed transcervically [1].