Perinatologist and twin expert, Dr. Larry Rand, describes the risks and advantages of placental laser ablation therapy, the most effective treatment for TTTS that has reached or exceeded stage 2. Expected long-term outcomes are also discussed.
Refer to Fetal Treatment Center
We've talked about the staging system for twin to twin transfusion and why that's so important to help us determine what the next best steps are to managing a complicated monochorionic twin pregnancy. In our experience, the most important differentiation is whether you are still stage one or you've developed stage 2 or worse disease. Stage 1 has a 50% chance of resolving and improving on its own. Stage two. You suddenly have an 80-90% chance of losing both fetuses. There's a phenomenal difference between stage one and stage two, which is why we make a really big deal about differentiating between them. If you have stage one disease, we'll work really hard to try to find an AA which gives us some reassurance that we expect things to remain relatively stable. If we can't find an AA, that doesn't mean one isn't there. But to keep the twins safe, they'll need very close surveillance with ultrasound to either demonstrate that they remain stable or improve, or to make sure that we catch it if they progress to stage 2 or beyond. With stage 2 twin to twin transfusion or worse. The best treatment option is laser ablation. Fetoscopic placental laser ablation is a procedure that involves inserting a 3 millimeter scope into the uterus and using the small camera that's embedded into that scope to find the one-way AV connections and burn or ablate. Them using a laser. Laser definitely has risks though. There is a 10 to 15% risk of something going wrong with the laser procedure. That risk does include breaking your water, or going into labor, or losing the pregnancy altogether. A 10 to 15% risk of something going wrong. is pretty significant, and we take that seriously. For comparison, an amniocentesis is something that people generally really wring their hands about. As long as you're having an uncomplicated pregnancy, is it worth taking the risk associated with an amniocentesis? Well, that risk is 1 in 400 or 0.25%. With laser, we're talking about 10 to 15%, and that's a significant risk, but you're comparing that risk to an 80 to 90% chance of losing one or both of the fetuses, and under those conditions and circumstances, it's acceptable. Unfortunately, although laser is the best treatment available for TTTS, it's far from perfect. The likelihood that you'll end up with two surviving twins is only 65%. The likelihood of having at least one surviving fetus is 80 to 85%. Perhaps most importantly, infants who've had twin to twin and were treated with a laser and survive have up to an 11% chance of a long-term neurologic injury. 2/3 of these injuries are pretty severe, like cerebral palsy, and the other third are milder, including things like learning disabilities, developmental delay, and milder cognitive deficiencies. The single greatest risk factor for having one of these neurologic injuries is being born at an early gestational age. And unfortunately, twins, especially monocryonic twins who've been complicated by TTTS and required laser therapy, are at risk of being born early. However, laser can be successful, and when it is, the average gestational age for delivery is 35 weeks, and that would be considered a fantastic outcome.
