Spinal fusion surgery has tended to carry with it the risk of blindness. However, a recent study suggests that the risk has dropped almost three-fold since the late 1990s.

“While there are significant complications that can result from spinal fusion surgery, it seems that blindness, a catastrophic and devastating complication, is one that has become far rarer in recent years,” says senior author Steven Roth, MD, FARVO, the Michael Reese Endowed Professor of Anesthesiology at the University of Illinois at Chicago College of Medicine, in a media release from University of Illinois at Chicago.

Among the nearly 480,000 spinal fusions performed in the US each year, there is a between one-in-1,000 and one-in-10,000 chance of blindness, aka ischemic optic neuropathy. Since the numbers of people receiving spinal fusion surgery has increased in the last 20 years, spinal surgeons and anesthesiologists have been concerned about this risk, per the release.

To determine whether the blindness rate as a result of these surgeries was stable, or increased or decreased over time, Roth and colleagues performed their study, which was published online recently in Anesthesiology.

According to the release, the team estimated that 2,511,073 spinal fusions were performed, resulting in 257 instances of ischemic optic neuropathy, or 1.02 per 10,000 surgeries. But over that time span, the risk decreased 2.7 fold, or 60%.

A significantly increased risk for ischemic optic neuropathy during spinal fusion surgery resulted from age over 50, male sex, receiving a blood transfusion during the procedure, and obesity. Roth attributes the decline in risk to the increasing use of minimally invasive surgical techniques.

“The characteristics of the patients undergoing spine fusion haven’t changed all that much over the years, although the population has aged,” Roth says in the release. “So the variables that must be contributing to the decline in blindness caused by spine fusion surgery are most likely the result of changes made in how the surgery is performed.”

Roth adds in the release that changes in anesthesia practice—such as stricter limits by anesthesiologists regarding how low they will allow the patient’s blood pressure to drop during the surgery—may also be driving the decrease in blindness risk.

[Source(s): University of Illinois at Chicago, Science Daily]