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].