Selective versus non-selective laser photocoagulation of placental vessels in twin-to-twin transfusion syndrome.

OBJECTIVE: We have recently described a surgical technique for the treatment of twin-to-twin transfusion syndrome (TTTS) that allows precise identification of vascular anastomoses (selective laser photocoagulation of communicating vessels, or S-LPCV). The purpose of this study was to compare S-LPCV with the previous non-selective technique (NS-LPCV) that targeted all vessels crossing the dividing membrane.

MATERIALS AND METHODS: Patients with TTTS were treated with NS-LPCV from May 1994 to June 1997 and with S-LPCV from July 1997 to December 1999. TTTS was defined as polyhydramnios of > or = 8 cm maximum vertical pocket (MVP) in the recipient twin and oligohydramnios of < or = 2 cm MVP in the donor twin. Outcome was measured as survival per number of pregnancies and per number of fetuses together with limited morbidity data.

RESULTS: NS-LPCV was used in 18 patients and 74 were treated with S-LPCV. Three patients interrupted their pregnancies electively after surgery (S-LPCV) and were removed from further analysis. Survival of at least one fetus was higher in S-LPCV (83.1%) than in NS-LPCV (61.1%) (P = 0.04), mostly due to a lower rate of dual intra-uterine fetal demise in S-LPCV (5.6%) than in NS-LPCV (22%) (P = 0.05). There were more hydropic fetuses in the NS-LPCV group (27%) than in the S-LPCV group (5.4%), but this difference did not account for the results. There was no difference in the survival per number of fetuses between the two groups.

CONCLUSIONS: S-LPCV represents an important evolution in the surgical treatment of TTTS. The use of this technique by all centers should allow better comparison of fetal survival and morbidity rates. S-LPCV should be the standard technique in trials comparing amniocentesis versus laser for the treatment of severe TTTS.