Role of Perineural Catheter in Pain Control and Opioid Consumption After Major Amputation of Lower Limb

The goal of this randomized controlled clinical trial is to evaluate the effectiveness of postoperative bupivacaine infusion through a perineural catheter in managing postoperative pain and to determine the opioid consumption among patients undergoing major lower-limb amputation surgery. The main questions it aims to answer are: * Does postoperative bupivacaine infusion through a perineural catheter provide better postoperative pain control as compared to intravenous opioid analgesia alone? * Does postoperative bupivacaine infusion through a perineural catheter reduce intravenous opioid consumption within the first 48 hours after surgery compared with intravenous opioid analgesia alone? * Does the postoperative Bupivacaine infusion through perineural catheter help in reducing the phantom pain at 6 months follow-up?

Inclusion Criteria: * Patients aged 18 and above * Patients undergoing lower limb amputation. * ASA status I to IV. * Patients under general or spinal anaesthesia Exclusion Criteria: * Patients with no allergies to study drugs (inje Bupivacaine 0.125%, Inje Tramadol, Inje Morphine) * Pregnant and lactating patients * Patients who require post-operative ventilatory support in ICU * Those with open wound of amputation stump * Procedures performed under peripheral nerve block