Objectives and Hypothesis: Our primary objective will be to create a pediatric pharmacokinetic profile of celecoxib in the blood and the central nervous system as well as explore the relationship between CYP2C9 polymorphisms and documented adverse events. The investigators hypothesize that the CSF concentrations of Celecoxib post ingestion are lower than plasma levels with a delayed peak concentration and directly related to dose, genotype, and age. The investigators expect that Celecoxib will improve quality of life and reduce discomfort when administered before and after a LP +/- BM.