How are stress fractures of the lower back usually treated?

Mostly non surgical: Lifestyle modifications physical therapy orthotic devices, such as corsets and braces not often surgery?

Conservative: Lower back stress fractures, usually called spondylolysis, are usually treated with non-operative means. Some docs recommend bracing, but others recommend pain-free core lumbar stabilization protocols. These are notorious for not healing, but most patients become non-symptomatic with spondylolysis. The condition may progress to instability (spondylolisthesis) over years or decades.