What do I need to know about lumbosacral spondylolysis?

Spondylosis. Spondylosis is simply arthritis of the disc and facets. This is not a common reason for spine surgery. It usually will cause back pain that is aggravated by activity. Now, if pressure is present on the nerves from the arthritis (spinal stenosis) that is a different story. I would try nonsurgical treatment first: physical therapy, arthritis meds, nerve blocks, & reserve surgery for failures.
Exercise. First. See your primary care provider to be sure of the proper diagnosis. Then be sure to take prescription exactly as prescribed. Stretching exercises often help arthritis of the spine.