Endoscopic intrauterine surgery in primates: overcoming technical obstacles

Lessons from the Barn to the Operating Suite: A Comprehensive Review of Animal Models for Fetal Surgery

The International Fetal Medicine and Surgery Society was created in 1982 and proposed guidelines for fetal interventions that required demonstrations of the safety and feasibility of intended interventions in animal models prior to application in humans. Because of their short gestation and low cost, small animal models are useful in early investigation of fetal strategies. However, owing to the anatomic and physiologic differences between small animals and humans, repeated studies in large animal models are usually needed to facilitate translation to humans. Ovine (sheep) models have been used the most extensively to study the pathophysiology of congenital abnormalities and to develop techniques for fetal interventions. However, nonhuman primates have uterine and placental structures that most closely resemble those of humans. Thus, the nonhuman primate is the ideal model to develop surgical and anesthetic techniques that minimize obstetrical complications.

Feasibility of ultrasound-guided percutaneous samplings in the pregnant baboon: a model for studies on transplacental transport

OBJECTIVE

A study was conducted to test the feasibility of cordocenteses and amniocenteses at different gestational ages in pregnant baboons.

STUDY DESIGN

Experiments were performed in 10 pregnant baboons at a median gestational age of 131 (range 92-169) days. At different time intervals, percutaneous samplings of amniotic fluid and fetal blood were performed under ultrasound guidance. Simultaneously, maternal blood samples were drawn.

RESULTS

With a median fetal weight of 431 g (range 111-690 g), 29 of 30 cordocenteses (96.6%) and all 30 amniocenteses and maternal samplings (100%) were successful in obtaining the required quantities for analysis. One cordocentesis was abandoned because of insufficient visualization of the umbilical cord due to a placental haemorrhage.

CONCLUSION

Percutaneous amniocentesis and cordocentesis can be performed with a high success rate in the pregnant baboon model. In combination with a 100% success rate in obtaining simultaneous maternal blood samples, this method is able to provide data on transplacental transport.

Gasless fetoscopy: a new approach to endoscopic closure of a lumbar skin defect in fetal sheep

OBJECTIVE

To develop a new endoscopic approach to the correction of a myelomeningocele-like defect in fetal sheep.

METHODS

The fetuses of 9 pregnant ewes, with an average gestational age of 115 days, were subjected to a 3.0 x 2.0 cm removal of the skin over the lumbar spine, performed through hysterotomy. The uterus was closed, and three 5-mm endoscopic cannulas, without valve mechanisms, were inserted. In the pilot phase (2 animals), we initially worked exclusively in the amniotic fluid space. In the study phase, we partially withdrew the fetus from the amniotic fluid to completely expose its back. By simply allowing air to enter the amniotic cavity (without gas injection), a working space was created using a uterine lift device. The skin around the defect was dissected, and a biosynthetic cellulose material was applied to cover the area. A continuous suture of the skin was performed to completely hide the material.

RESULTS

The combined air/fluid space allowed the skin to be successfully closed in 6 out of 7 cases in the study phase. All fetuses were alive at the end of the procedures. Time to complete the endoscopic part of the procedure fell from 3 to 1 h by the end of this series. Premature birth occurred in 2 of the 4 cases allowed to continue with the pregnancy.

CONCLUSION

A new gasless fetoscopic surgery technique was developed as an alternative to current techniques used for fetal endoscopic surgery.

Foetal surgery and cleft lip and palate: current status and new perspectives

Now-a-days, high-resolution ultrasound allows an accurate and relatively early diagnosis of congenital malformations. In a limited number of such conditions foetal surgery may be lifesaving. However, premature labour has been the major drawback for open foetal surgery. Recently, improvement of video-endoscopic technology has boosted the development of operative techniques for feto-endoscopic surgery, which has been demonstrated to be less invasive than the open approach. Main clinical application of fetoscopic procedures today is the treatment of feto-foetal transfusion syndrome. Although still in development, feto-endoscopic surgery seems to offer new hope for surgical foetal therapy not only in cases of life threatening conditions. Experimental intrauterine correction of cleft lip and palate (CLP) has been lately performed using the feto-endoscopic approach. This procedure offers two major advantages: first, scarless foetal wound healing and bone healing without callus formation, which would also allow a better/normal maxillary growth, and second, significant decrease of foetal and maternal morbidity. Herein, we report the current status of experimental and clinical foetal surgery and propose possible directions for continuing research to make intrauterine procedures safer. Furthermore, we discuss current knowledge and new perspectives of experimental foetal cleft lip and palate repair, which in the future may lead to such excellent results in the operative treatment of clefts, that less or no secondary corrections and therapies, such as orthodontic, dental, logopedic, etc. would be needed. Only if these conditions can be fulfilled, will we be able to improve substantially our therapy for the human foetus with a cleft lip and palate. In spite of all efforts, however, it must be considered that it may not ever be possible to find the optimal treatment method for this or other craniofacial malformations.

Intrauterine autogenous foetal bone transplantation for the repair of cleft-like defects in the mid-gestational sheep model

AIM

The success of intrauterine surgery in treating non-life-threatening malformations such as myelomeningocoele, has also renewed strong interest in using this technique for treating craniofacial malformations. Nevertheless, the only experimental cleft-like defect models known, are those concerning wound healing of soft tissues.

MATERIAL AND METHODS

Attempts were made to repair artificial cleft-like defects including transplantation of 11 autogenous foetal bone grafts from the iliac crest or ulna, and were randomly assigned to three study groups, using the mid-gestational sheep model. In a 4th study group, lyophilized collagen, a bone-regenerating bioresorbable implant material, was used to fill the alveolar defect.

RESULTS

In all groups, there was a slight degree of asymmetry and thinning of the lip. Radiological studies demonstrated a variable degree of abnormality of the maxilla, ranging from none to a mild deviation. Three-dimensional computer tomography, two-dimensional maximal intensity projection findings, and histological analysis confirmed bony healing of the alveolar cleft-like defect.

DISCUSSION/CONCLUSION

Intrauterine autogenous foetal bone transplantation for the repair of cleft-like defects in the sheep is feasible. This is a reliable and valuable model toward a possible clinical application for intrauterine treatment of clefts.

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.

Fetal endoscopic surgery: lessons learned and trends reviewed

PURPOSE

Fetal surgery is performed increasingly with minimal access approaches. The authors report their experience with fetal endoscopic procedures (fetendo) with emphasis on changing techniques and outcome trends.

METHODS

All fetal endoscopic cases performed at a single institution from January 1996 to August 2001 were reviewed (n = 66). Cases were examined with respect to year performed, type of operation, operative data, and outcome.

RESULTS

Twin-twin transfusion syndrome (26 cases) and congenital diaphragmatic hernia (35 cases) were the most common diseases treated. From 1996 to 2001, there was a decrease in average operating time (256 to 127 minutes [P =.0006]), number of ports utilized (3.8 to one [P =.00001]), pump volume (28.7 to 2.7 L [P =.00001]), and estimated blood loss (408 to 29 mL [P =.008]). In addition, port size changed from 10 mm to 5 mm. Chorioamniotic separation (31 of 66), premature rupture of membranes (32 of 66), chorioamnionitis (12 of 66), and fetal death (10 of 66) continued to be significant complications.

CONCLUSIONS

Fetal endoscopic surgery over the last 6 years has evolved toward shorter operating time, the use of smaller and fewer ports, decreased pump fluid exchange, and decreased blood loss, with the types of cases centered on twin-twin transfusion syndrome and congenital diaphragmatic hernia.

Genetics of cleft lip and palate

Cleft lip with or without cleft palate (CL/CP) is one of the most common structural birth defects, with treatment including multiple surgeries, speech therapy, and dental and orthodontic treatments over the first 18 years of life. As a result of the treatment interventions, pediatric nurses may be required to care for these children beginning in infancy through adolescence. Providing care for these patients and families can include educating patients and parents about the genetics of CL/CP, as well as meeting their immediate medical needs. A basic overview of normal lip and palate development, classification of clefts, pathophysiology of CL/CP, incidence, inheritance, genetic and environmental causes, genetic counseling, prenatal diagnosis, fetal surgery, and nursing implications is provided to educate pediatric nurses about the basics of the genetics of CL/CP.