An L4-5 disc bulge in your MRI, assuming your MRI radiologist meant a small disc protrusion in his report, represents an ageing disc that has naturally lost its water content and its cushion and height with time, resulting in a bulge, like a bulging "worn out" car tyre. Because this is a natural ageing process, it cannot be reversed or “cured” and disc bulges can also be seen in MRI even if you have no back pain as you age.
But in the presence of back pain from disc bulge, treatment must be started to “depressurise” the disc (usually with physiotherapy lumbar traction) and strengthen your spinal core muscles (usually with physiotherapy) in order to reduce the risk of it worsening to a larger “slipped” disc in the future, like a “burst” car tyre, requiring surgery to treat in the end. Prevention is always better than cure.
Otherwise, in the absence of disc rupture and nerve compression, the recently published North American Spine Society Guidelines on Back Pain DO NOT recommend surgery (including discectomy, fusion, discoplasty, nucleoplasty and laser) as a treatment .
