What Causes Pain And Weakness In Leg When Suffering From Synovial Cyst?

I had a large synovial cyst at L4 & L5 two years ago with severe sciatic pain. March 2009 I had lumbar fusion at L4 & L5 with removal of the cyst. In August 2010, a smaller cyst at L3& L4 was discovered. I am having pain down right leg, with weakness and numbness also right arm weakness and numb feeling. Is the sciatic involved at this level as it was with the previous cyst location?