The study will be performed in Assiut University Hospitals, after obtaining approval from the local ethics committee and written informed patient consent. All patients will have a peripheral IV cannula 18 G inserted; standard non-invasive monitors will be applied. All the patients will be preloaded with 10 ml/kg Ringer's lactate solution intravenous. Intrathecal block under strict aseptic conditions will be performed in sitting position at L3-4 or L4-5 inter-spinous space with 25G pencil-point spinal needle. All patients will receive intrathecal 10 mg of 0.5% hyperbaric bupivacaine.