Surgery in prolapsed lumbar discs is indicated if there is any compression of the nerve
roots and if you have symptoms that fit with the scan findings. If your symptom is only low back pain
and if the MRI
shows dessicated L4/5 disc (dessication basically means that the disc has dried out), surgery may not be helpful. Surgery for improving he low back pain alone is successful in only about 50% of cases. Therefore, other non-operative methods may be more useful in your case.
Hope this helps.