Pain returns shortly after treatment

I have a patient with pain that starts in buttock area and travels down the leg; GB & UB channel then into big toe (SP). He finds relief while the needles are in but then it returns within a couple of hours after leaving.

He has already had the gamete of western tests, and they say that he has sciatica with bone spur growth in L5 are.

I am wondering what is going on, as to why the pain is returning so quickly?

Thanks