To follow on from a study in a recent “neonatal updates”, there is a new publication from an Australian group that have been pursuing a prospective cohort of full term infants who had major surgery in the first 90 days of life.
In contrast to the other study, this was prospective, population based, and only included major surgery (defined by opening of a body cavity). The early developmental results have already been published Walker K, et al. Early developmental outcomes following major noncardiac and cardiac surgery in term infants: a population-based study. The Journal of pediatrics. 2012;161(4):748-52 e1.
Now the authors have been testing the infants at 3 years of age. Walker K, et al. Developmental outcomes at 3 years of age following major non-cardiac and cardiac surgery in term infants: A population-based study. J Paediatr Child Health. 2015. They examined 62 infants who had cardiac and 124 who had non-cardiac surgery, and 162 controls, all from New South Wales. The Bayley scales of infant development, version 3 were used. Basically the non-cardiac surgery babies tested lower than the controls on just about all the subscales, and the cardiac surgery babies tested lower than the controls on just about all the subscales.
The proportion of babies whose scores fell into the mild, moderate and severe delay definitions were also increased. Most, as you would expect, were mildly affected, but nevertheless they were affected, and for expressive language and gross motor delay the proportions affected are substantial, 1/3 of the cardiac, and 1/6 of the non-cardiac surgery infants, compared to 1/20 of the controls (all of which were mild except fro 3 babies in the expressive language subscale who were moderate). With proportions like that these babies should all be followed up in order to identify those who may benefit from intervention. If we could identify them early then follow up could be selective. It seems (from other data) that more than 1 surgery increases the risk (Wilder RT, et al. Early exposure to anesthesia and learning disabilities in a population-based birth cohort. Anesthesiology. 2009;110(4):796-804.), and longer anesthesia also seems a risk factor.
Several studies of specific types of surgery usually have shown similar results, (for example for oesophageal atresia and gastroschisis) so it is presumably just the fact of having surgery/anesthesia that is important, and not pre-existing associated CNS anomalies. Although some details of how the surgery is done have been studied, such as circulatory arrest times, and hemodilution (both in cardiac surgery), most of the details of the surgical or anesthetic techniques have not been evaluated.
A good recent review is available Sinner B, et al. General anaesthetics and the developing brain: an overview. Anaesthesia. 2014;69(9):1009-22.