Maybe. According to a recent study from Stanford University, psychosocial factors do impact the outcome of spinal fusion. In fact there are many other studies that show psychosocial factors significantly affect the results of various therapies.
Most surgeons suggest at least six months of conservative care before advising surgery. If your mother hasn't tried some of these other treatment options, she might want to look into one or two. Antiinflammatory drugs, acupuncture, physical therapy, and exercise are just a few of the possible treatment choices.