Do you prescribe prophylactic steroids with spine SBRT?

I do not use prophylactic steroids for spine radiosurgery. I indeed start tapering steroids from the time of consultation if the patient was already on steroids. After radiosurgery of spinal cord compression, I start tapering on the day of radiosurgery.

Pain flair seems to occur in 10-20% of patients...

I remember a case of L3 met (from NSCLC) that I treated with single fraction SBRT (18 Gy in 1 fx) several years ago. The pain before treatment was 8 out of 10 on BPI. No prophylactic steroid was used. Within 24 hours after SBRT, the BPI score dropped to 0-1 out of 10 but the patient started noticing...