CHICAGO, June 30 (UPI) -- The risk of blindness after spinal fusion surgery has plunged in the last two decades, even as the surgery has become one of the most common in the United States, according to a recent study.
Patients undergoing spinal fusion are nearly three times less likely to lose their sight after the procedure, researchers at the University of Illinois at Chicago found in a recent study, which they attribute at least partially to improvements in how the surgery is performed.
Spinal fusion is a last-resort treatment for pain and nerve damage in which surgeons remove the cartilage from between two vertebrae and join them using bone grafts and screws. The surgery is necessary if a disc degrades, caused by anything from trauma to obesity to aging, and since there is no blood supply to the disc, it does not regenerate like other tissues, causing significant discomfort for patients.
In addition to shifts in how anesthesia is used during the surgery, an increase in minimally invasive surgeries and improvement in how they are done has likely also contributed to the drop in blindness, researchers suggest.
"The characteristics of the patients undergoing spine fusion haven't changed all that much over the years, although the population has aged," Dr. Steven Roth, a professor of anesthesiology at the University of Illinois at Chicago's College of Medicine, said in a press 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."
For the study, published in the journal Anesthesiology, researchers analyzed medical data on the outcome of spinal fusion surgeries linked to ischemic optic neuropathy collected between 1998 and 2012 as part of the Nationwide Inpatient Sample.
Of 2,511,073 patients who had the surgery during the 14-year span, 257 developed ischemic optic neuropathy, an incidence of 1.02 cases per 10,000 surgeries, but over that period the risk of losing sight after the surgery dropped 60 percent.
Among factors increasing risk for going blind after spinal fusion surgery was advanced age, blood transfusion, obesity and being male, while the data showed being female had a protective effect.
"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," Roth said.