Surgery in the Womb Saves Twins Lives

Cassellius Twins
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Groundbreaking new surgery on identical twins was performed within the mother's womb leading to their successful birth this week in Minnesota. Babies Gavin and Owen Cassellius were diagnosed at 19 weeks of pregnancy as having a shared placenta where one twin looses blood to the other and the death of one or both is them is the usual result. This time, doctors teamed up at Abbott Northwestern Hospital in Minneapolis and Children’s Hospitals and Clinics of Minnesota and attempted a new procedure called fetoscopic laser ablation. They threaded a tiny laser light into the uterus and severed the shared blood vessels that cause the imbalance of blood flow.

Twin to twin transfusion syndrome occurs in 5-10% of identical (monochorionic) twin pregnancies. Because one twin receives more blood than the other, the growth rates are uneven and premature birth and severe complications can occur. This unequal placental sharing is usually diagnosed by ultrasound and only occurs with identical twins. There is a 70-80% mortality rate without treatment.

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Previously the treatment was amnioreduction where amniotic fluid is repeatedly withdrawn from the placenta through a large needle placed into the sac of the recipient twin. Complications are common and despite treatment, the odds of saving these fetuses have been low.

Fetoscopic laser surgery is more invasive than amnioreduction and has a greater risk for the mother. It was first tried in 1990 with poor results but a few centers around the world have continued perfecting this treatment in an attempt to save twins. In some reports from centers who do the procedure, women treated by fetoscopic laser instead of serial amnioreduction had a higher proportion of pregnancies with greater than one survivor. (79% vs. 60%).

Drs. William Block and Brad Feltis decided not to accept the certain death of the Cassellius twins after they traveled to Belgium to learn the technique. They performed the operation on July 3 and watched closely to see if the blood flow and fluid levels returned to normal and if the growth rate of the twins leveled out. Dr. Block reported, “Really, within about 48 hours we start to see those corrections.”

The twins were born at 36 weeks, which is almost full term. Their weights were almost identical at 5 #, 9 ounces and 5 #, 4 ounces. The “miracle twins” will be going home with their delighted parents to Hudson, Wisconsin.

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