TREATMENT OF THE TWIN-TWIN TRANSFUSION SYNDROME - INITIAL EXPERIENCE USING LASER-INDUCED INTERSTITIAL THERMOTHERAPY

This paper describes our initial experience with laser-induced interst itial thermotherapy (LITT) for the treatment of the twin-twin transfus ion syndrome (TTTS). This procedure was utilized in four pregnancies - three monochorionic twin pregnancies and one triplet pregnancy (20-26 weeks of gestation) - with severe TTTS with fetal dropsy, polyhydramn ion of the acceptor, and anhydramnion of the donor. In vitro examinati ons of placental tissue had shown that laser coagulation can be monito red by sonography, hence we used this method for the first time in the se four pregnancies. Blood vessels connecting the two umbilical cords were determined prior to the treatment using a new ultrasound color te chnique which is highly sensitive and capable of representing slow blo od flow velocities. A 1.2 mm thick puncture needle was then directed t o the shunt under on-line ultrasound central. All patients had an ante rior wall placenta. The laser fiber was inserted via this thin needle. A coagulation time of 2-3 min was necessary at 3 W. In the one twin p regnancy the intrauterine fetal death of the smaller child occurred 10 weeks after LITT, the other child survived and is healthy. A cesarian section was necessary in another twin pregnancy 1 week after LITT due to the intrauterine death of the smaller child. In the third twin pre gnancy, the donor, who had already had distinct bradycardia prior to t he treatment, died immediately after LITT. The intrauterine fetal deat h of the donor in the triplet pregnancy occurred 3 days after LITT onc e the volume of amniotic fluid had basically returned to normal. The t ragic intrauterine death of the uninvolved child occurred 13 weeks lat er as a result of umbilical cord strangulation, the surviving child is healthy. All four pregnancies were severe and advanced cases of TTTS with a very poor prognosis, leaving us with no other alternative to th e described method of treatment, The instruments we used are a lot thi nner than those utilized for fetoscopic laser treatment to date. Furth ermore, it is not necessary to penetrate the amniotic sac in patients with an anterior wall placenta; intraplacental vessels can be coagulat ed, and the laser energy required for LITT is also much lower In our o pinion these advantages justify the utilization of LITT under more pro mising conditions than those described above.