The major risks specific to lumbar spinal surgery include permanent nerve damage, recurrent disk herniation and lack of relief from symptoms. Major risks associated with all major surgeries also apply, including heart attack, stroke, bleeding, infection, reaction to anesthesia or other drugs, and blood clots, according to WebMD.
The risks vary among different types of surgery. For the most common spinal surgery, in which surgeons remove a spinal disc and fuse the vertebrae above and below it together, there is a risk that the loss of mobility between the fused vertebrae places extra stress on discs above or below the fusion site, causing them to become herniated, according to Spine-Health. In another type of surgery, which has surgeons using an artificial disc to replace the original disc, there may be a slight risk of the artificial disc slipping out of place or malfunctioning, according to WebMD.
An individual's risk for major medical complications such as stroke or heart attack depends on the patient's age and overall health before surgery. In one study of more than 12,000 patients who underwent lumbar spinal surgeries between 1998 and 2009, the risk of major medical complications was found to be less than 1 percent for patients under age 50 and 4 percent in patients age 80 or older. In the same study, patients with major medical conditions prior to surgery suffered surgical complications at a rate 3 times higher than those with only minor medical conditions or none at all, as Science Daily reports.