A Southern California fetal surgery institute, one of only a handful in the United States, has posted enormously successful rates in treating a dangerous disorder that affects 10 percent of unborn identical twins.
One of the largest studies conducted in the United States for the treatment of Twin-Twin Transfusion Syndrome (TTTS) with laser surgery has found that the USC Fetal Therapy Program at Hollywood Presbyterian Medical Center has achieved a 91 percent survival rate for at least one fetus and a 72 percent survival rate for both fetuses.
Conducted from March 2006 through March 2008, the groundbreaking study examined 99 consecutive patients who underwent laser surgery for the treatment of TTTS. The majority of the placentas subsequently underwent pathological review to analyze the technical success of the surgery.
"Using a modification of the standard laser technique, we found significantly improved survival in the especially vulnerable donor fetus," said Dr. Ramen Chmait, who led the study and conducted all 99 surgeries. He is among a handful of physicians who perform fetal laser surgery.
TTTS occurs only in monochorionic pregnancies (identical twins who share a placenta). It results in unequal sharing of blood and disproportionate distribution of blood volume between the twins. One twin receives excess blood volume, while the donor twin becomes blood-volume depleted. If untreated early in pregnancy, there is a 90 percent chance that both twins will die.
TTTS is usually diagnosed with a routine ultrasound during the second trimester--at a time when most expectant parents are beginning to adjust to the news of having twins.
"My first prenatal appointment revealed eight-week-old twins; my second, identical twins; and my third appointment revealed two little girls. It seemed like one shock after the next, with blended emotions of delight and uncertainty," says Jody Madden, who was to go on to have life-saving surgery performed by Dr. Chmait.
During that second appointment, Jody recalls that her perinatologist mentioned a possibility of very serious complications in cases of identical twins.
As time progressed, Jody, who already had a 17-month-old child, felt that the pregnancy was progressing unusually. She experienced excruciating headaches and extreme body pain. The skin around her belly had become abnormally taught and painful.
Her gynecologist ordered an ultrasound, and a diagnosis of TTTS was made. Jody was told she could do nothing--and inevitably miscarry at around 22 weeks--or undergo fetal surgery to save at least one fetus, though her perinatologist was pessimistic about that outcome.
Jody would meet Dr. Chmait the next day.
Three hours after her appointment with Dr. Chmait, Jody underwent fetal laser surgery. After 11 weeks of strict bed rest, she went into preterm labor at 33 weeks to deliver Giselle Kora Madden and Ginger Kalina Madden, now thriving 14-month-olds.
"Today, the only evidence that TTTS struck our home is the tiny scar on my skin," says Jody. "Dr. Chmait is just a humble doctor--who has given the gift of life to families across the globe."
In successful TTTS fetal surgery, the shared blood vessels that allow transfusion from one twin to the other are identified and laser-occluded (blocked, so that blood flow ceases), allowing each fetus to have use of a separate portion of the placenta.
"Laser surgery renders the twins independent of each other," explains Dr. Chmait,
Dr. Chmait has performed approximately 200 cases of laser surgery for the treatment of TTTS at the Institute for Maternal Fetal Health, which is located at Hollywood Presbyterian Medical Center in Los Angeles, in collaboration with University of Southern California and Children's Hospital Los Angeles.
About the Study
To measure surgical success, the 99 patients in the study were asked to submit placentas for pathological review, and 73 percent agreed to do so. Those placentas were sent to Dr. Kurt Benirschke at the University of California San Diego for analysis.
There, Dr. Benirschke found that patent anastomosis (blood vessels that remained open) occurred in only 4 percent of patients who participated in the review.
"When discussing outcomes, success is based on identifying all vascular communication," says Dr. Chmait--that is, whether any blood vessels remained open and so continued to allow transfusion from one fetus to the other.
Hollywood Presbyterian Medical Center