EMBRYOSCOPY AND FETOSCOPY

Fetal surgery

Fetal surgery has emerged from the realm of medical curiosity into an exciting, multidisciplinary specialty now capable of improving patient outcomes for a wide variety of diseases. Recent advances allow prenatal providers to both accurately diagnose and treat many fetal anomalies while maintaining maternal safety. As the initial postnatal health care providers to the majority of these newborns, neonatologists need to be familiar with some of the more recent state-of-the-art procedures currently being used. In this review, the authors discuss the prenatal evaluation process and various operative approaches (ie, open hysterotomy, fetoscopy, and percutaneous) to conduct fetal surgery. They then analyze the effectiveness of some of the more established and experimental prenatal therapies that are being performed for a number of fetal anomalies, including twin-twin transfusion syndrome, thoracic malformations, airway obstruction, congenital diaphragmatic hernia, myelomeningocele, and aortic valve stenosis.

Intrauterine endoscopic creation of urinary tract obstruction in the fetal lamb: a model for fetal surgery

OBJECTIVE

Our purpose was to evaluate the feasibility of intrauterine endoscopic fetal surgery in a fetal lamb model by creating a urinary tract obstruction.

STUDY DESIGN

Lower urinary tract obstruction was created by ligation of the urethra and urachus in 21 fetal lambs, eight at 95 to 105 days' gestation (term 145 days) and 13 at 70 to 75 days. The endoscopic approach consisted of a 0-degree 5 mm telescope, three 5 mm cannulas, uterine distention by amnioinfusion, and adapted instrumentation. Intrauterine fetal monitoring included temperature and pulse oximetry registration.

RESULTS

In 20 cases the urachus could be identified and ligated inside the umbilical cord. The urethra was ligated in the anterior abdominal wall (n = 7) or obstructed at the level of the penis (n = 13). Mean fetal heart rate was 147 +/- 35 beats/min, and fetal temperature at the end of intervention was 38.14 degrees +/- 2.1 degrees C. The overall postoperative survival rate was 76%.

CONCLUSION

Urinary tract obstruction can be created endoscopically in the fetal lamb. This operation can serve as a model for endoscopic fetal surgery.

Hydrolaparoscopy in the rabbit: a fine model for the development of operative fetoscopy

OBJECTIVE

Our goal was to become adept at performing laparoscopic procedures within a fluid medium and at using miniature instruments in a small animal model.

STUDY DESIGN

Adult female New Zealand rabbits underwent carbon dioxide laparoscopy while they were under general anesthesia with the use of 2 mm instruments. The abdominal cavity was filled with lactated Ringer's solution. Visualization of the intraabdominal organs and surgical procedures were performed below the fluid level.

RESULTS

Excellent visualization of the abdominal organs below the fluid level was obtained. Several surgical tasks were accomplished, including cutting and coagulation of the uterine horns with monopolar electrocautery, creation of a defect in the mesovarium and mesometrium, extracorporeal knot tying, and intraabdominal cutting of suture material. Relatively high amounts of energy were needed during electrocautery within the liquid medium (> 25 W). Occasional fluid and gas leakage through the skin punctures was prevented with accessory clamps.

CONCLUSION

Hydrolaparoscopy can be performed in the rabbit with miniature instruments. As it simulates the human intraamniotic environment, it is a useful model for the development of operative fetoscopy.

Effect of endoscopic white light on the developing visual pathway: a histologic, histochemical, and behavioral study

OBJECTIVE

We examined the potential teratogenic effect of endoscopic white light on the developing visual pathways.

STUDY DESIGN

The right eye of chicken embryos (n = 22) was exposed to maximal endoscopic light intensity on day 10 of development. At day 17 of development the histologic characteristics of the light-exposed retinas were compared with those of the control embryos (n = 4). Normal functioning of the light-exposed eye was assessed by intravitreal injection of wheat germ agglutinin-horseradish peroxidase and observation of its axonal transport pattern to the diencephalic and mesencephalic visual centers. Axonal transport patterns were compared with those found in previous studies of normal embryos. Behavioral feeding patterns were compared between two groups of newly hatched chickens, one exposed to endoscopic light after hatching (n = 13) and the other, an unexposed control group (n = 12).

RESULTS

No evidence of retinal damage, altered axonal transport or altered feeding patterns could be found between control and experimental animals.

CONCLUSION

Endoscopic white light does not appear to be harmful to the developing retina and visual pathway.