Prilocaine theoretically could provide faster onset because of its lower pKa (7,7) compared to bupivacaine (8,1). The primary objective of this prospective double blind randomized trial is to determine block onset of spinal hyperbaric prilocaine compared to bupivacaine, both with a small dose of sufentanyl as an additive.The primary hypothesis is that a significant larger amount of patients will gain surgical readiness within 8 minutes after spinal injection of prilocaine with sufentanyl compared to bupivacaine with sufentanyl. Surgical readiness is defined as a sensory block level of T5 tested by loss of cold sensation.