Neuraxial anesthesia is commonly performed for all surgical procedures carried on lower abdomen, pelvis and lower limbs to provide adequate surgical anesthesia and analgesia. It has a definite advantage over general anesthesia by blocking nociceptive impulses from the operative site, reduced blood loss and decreased incidence of deep vein thrombosis. Levobupivacaine has become popular for central neuraxial blocks in this century. The main advantage includes ease of technique and reliability. Levobupivacaine a pure s-enantiomers of bupivacaine are safer alternative for regional anaesthesia than its counterpart with lower toxicity profile. Opioids are added to local anesthetic drugs intrathecally to provide synergistic effect and to improve the quality of intraoperative and postoperative analgesia. These agents when combined together result in a reduction in the dose of both classes of drugs, decreasing the likelihood of side effects related to each. 

Extensive search of literature reveals that though the studies have been conducted with our additives with the drug bupivacaine, but a specific study comparing the additive effect of both the drugs with the recently introduced drug Levobupivacaine and a suitable dose required intrathecally has not been done extensively. Therefore, the present study is designed to compare the effect of intrathecal butorphanol and nalbuphine as an adjuvant to levobupivacaine in subarachnoid block. 

The specific outcome measures to define the performance of our study will primarily include comparing the effect of both the adjuvant drugs administered on the duration of motor and sensory blockade.