The findings of new research suggest a new potential side effect of major surgery, indicating that the procedures may come with an increased risk of long-term impairment to a person’s brain function.
Researchers from the U.S., U.K. and France found that major surgery doubled the odds of experiencing substantial cognitive decline. While it does increase the risk of brain function decline, medical treatment in the hospital increased the risk of decline even more.
The findings were published August 7, in the journal The BMJ, involving a study with 7,500 patients in the United Kingdom who took as many as five cognitive assessments between 1997 and 2016, in the Whitehall II study testing things like thinking skills, memory, reasoning and verbal fluency.
The study focused on major hospital admissions requiring more than one overnight stay during follow-up. Overall, there were more than 4,500 operations, 4,300 medical admissions to the hospital, and 151 people suffered a stroke.
Having major surgery was associated with patients facing double the risk of having their brain function impaired. However, the overall risks are small. The impairment was the equivalent on average to less than five months of aging. Researchers accounted for the expected age-related decline in brain function before factoring the risk.
In comparison, admissions for medical problems treated with medications were linked to an additional aging of 1.4 years. People who suffered a stroke had an increased risk of 13 years of cognitive aging.
Substantial cognitive decline occurred in 2.5% of participants with no hospital admissions, 5.5% of surgical admissions, and 12.7% of medical admissions.
Compared to patients with no major hospital admissions, those with surgical or medical events were more likely to have substantial cognitive decline from their predicted trajectory of typical cognitive aging.
Similarly, emergency surgery was linked to greater cognitive decline than non-emergency procedures.
It is unclear how surgery may affect brain function and this study didn’t focus on cause and effect. However, researchers think inflammation, strokes, mini strokes and medications taken around the time of surgery may be factors.
Additionally, anesthesia also may play a role as well. One study found a connection between lengthy doses of anesthesia during surgery or repeat exposure to general anesthesia and an increased risk of damage to a child’s brain development.
“Overall our data suggest that major surgery is associated with a small long term mean change in the age related cognitive trajectory, with the odds of substantial decline doubling. Hence although the mean association is small and the absolute incidence of substantial cognitive decline is low, major surgery is associated with a long term effect on cognition,” the researchers determined. “This information should be conveyed to patients and be weighed against the potential health and quality of life benefits of surgery during informed consent discussions with patients.”