It’s not often that infants need multiple surgeries in the first two years of life, but for those who do, there may be long-terms risks associated with visits to the operating room, a new study finds.
In a study published in the journal Pediatrics, Dr. Randall Flick and his colleagues at the Mayo Clinic report that infants who undergo multiple surgical procedures before age 2 may show developmental problems that go beyond the risks of the procedures themselves.
He and his team found that the association had to do with the anesthesia: babies who had multiple exposures to anesthesia had more than twice the rate of learning disabilities by age 19, compared with children who hadn’t had operations. The researchers made several different evaluations of the children’s cognitive and learning abilities as they grew older, including standardized tests of reading, writing, language and math, as well as group achievement tests and enrollment in special programs for emotional or behavioral disorders.
While multiple exposures to anesthesia were associated with an increased risk of learning disorders, single exposure was not.
How did the researchers know that the heightened risk was attributable to the anesthesia, and not the condition for which the children needed surgery in the first place? Many of the infants in the study were anesthetized in order to have tubes put into their ears to drain excess fluid, a common problem for young babies that is not associated with learning disorders. Other surgical procedures included hernia repairs and eye surgeries, which are also not associated with learning disabilities, Flick says.
In addition, Flick and his team matched each of the 350 youngsters who had had surgery before age 2 with two matched controls who hadn’t had surgery. Of course, the scientists were not able to match the surgery group with controls who had the same condition but did not undergo surgery, since it would have been unethical for children in need of surgery to be denied the procedures.
To account for differences in overall health status between the surgery group and the controls, Flick ranked all children according to scale that is commonly used by anesthesiologists to assess the general strength of their patients’ health before surgery. This allowed Flick and his colleagues to match children by their particular health status, and approximate a perfect control group. The researchers also accounted for known factors that influence learning disabilities such as birth weight, gestational age, mother’s education, and baby’s gender.
“I believe these results are concerning, and not just based on our findings, but because the Food and Drug Administration has carried out a series of studies on monkeys, and showed that monkeys at four years old have persistent learning problems after being exposed to anesthetics very early in life,” says Flick. “Put our data in context with that information, and it raises the bar.”
But whether that bar is high enough to change the advice doctors currently give parents with infants who face surgery is a different matter. “We still don’t have enough information to tell parents what they should or shouldn’t do,” he says.
In fact, the FDA convened a committee, on which Flick served, to look into the potentially long lasting effects of anesthesia on young babies. After a review of the literature, which included preliminary results of the current study, the committee members could not come up with definitive guidelines for parents. “We decided the advice was too vague and uninformative,” says Flick.
So, for now, it’s up to individual doctors and parents to decide on the specific risks and benefits of exposing infants to anesthesia. To help clarify the issue, Flick is preparing another study that he hopes will target anesthesia’s effects more accurately; he plans to compare outcomes in children who undergo repair of inguinal hernias (in which parts of the intestines poke through weak portions of the protective abdominal wall) under local anesthesia of the spine to those in children who are put under general anesthesia.
That research may also help highlight the differences in the way local and general anesthesia work. Doctors believe that general anesthetics may accelerate the normal pruning, or death, of neurons that occurs early in life, as babies’ brains, which are constantly forming new connections, feel out which ties will be essential and which are dispensable. Exposure to the agents in anesthesia, for some reason, triggers nerves to die off, which can lead to thinner neural networks and contribute to learning problems later in life.
Flick also notes that the anesthetic drug involved in the current study, which included children born between 1976 and 1982, is no longer used. But that agent is part of a larger family of anesthetics that are common in ORs today and likely have similar effects.
And as frustrating as the findings are, especially for parents who may need to make a decision about whether their child should undergo a surgical procedure, Flick says the results will continue to add to our knowledge about how the youngest brains react to being put to sleep. The more information doctors have, the better advice they will be able to provide to parents.