Spinal anaesthesia is the most commonly used technique for lower limb orthopaedic surgeries as it is very economical and easy to administer. This is due to the factors like avoiding the risks of general anesthesia such as pulmonary aspiration, bronchospasm, laryngospasm, cardiovascular response to intubation or risk of failed intubation and also allowing a patient to remain awake and enjoy the Painless experience of surgery. It also provides effective pain relief during intra operative and early postoperative period. Spinal anaesthesia also has rapid onset and low failure rate.

Spinal anesthesia is performed by placing a needle between the lumbar vertebrae and through the dura to inject anesthetic medication. Levobupivacaine, a new local anaesthetic, has been recently introduced into clinical practice because of its lower toxic effects for heart and central nervous system. Administrating the combinations of other classes of analgesics with local anesthetics has used to increase the duration and reduce side effects of analgesia. Some drugs have been used as adjuvants in spinal anesthesia to prolong intraoperative and postoperative analgesia including opioids (morphine, fentanyl and sufentanyl to hydromorphone, buprenorphine and tramadol), alpha2 agonists, neostigmine, vasoconstrictors, etc. Clonidine and dexmedetomidine are two alpha2 agonists affecting via pre- and post-synaptic alpha2 receptors.

For this a total of 60 patients (n = 60) undergoing lower limb orthopaedic surgeries will be randomly divided into two groups ( Group A and Group B). Group A patients will receive Isobaric Levobupivacaine 0.5% (3ml) with preservative free Dexmedetomidine 5mcg and Group B patients will receive Isobaric Levobupivacaine 0.5% (3ml) with preservative free Fentanyl 25mcg to subarachnoid block.

Patient will be received in operation theatre, intravenous cannula will be secured and hemodynamic variables will be noted. Surgery will be started after T10 level sensory blockade will achieve. Quantitative values of time of onset and duration of sensory and motor blockade, time taken to achieve maximum sensory blockade will be recorded.