6 days after right side l5s1 microdisectomy....pain in left buttock centered and not radiating...excruciating lasts 1/2 hour, steroids help. ?

Possibly...: Oral steroids are often prescribed although their benefit is less than clear. A recent study showed that they improve function, but not necessarily pain in patients with radicular symptoms (ie: pain radiating down the leg). The pain you are experiencing may be related to back spasm as a result of the surgery and will likely improve with time.