Lumbar laminectomy and discectomy are commonly performed surgery, which is associated with significant postoperative pain and patient discomfort.  General anaesthesia and spinal anaesthesia have both shown to be suitable techniques for patients undergoing lumbar spine surgery. GA may be preferred because of greater patient acceptance and the ability to perform operations of long duration in the prone position with a secured airway. Anaesthesiologists who favour regional techniques, however, believe regional anaesthesia reduces blood loss and improves operating conditions by decreasing peripheral venous pressure which reduces venous blood loss in the operative field. In addition, since these operations are usually performed in the prone position, the awake patient can self-position to avoid nerve injury to the brachial plexus and pressure necrosis to the face that may occur in the mispositioned patient under GA. In two uncontrolled large retrospective trials, spinal anaesthesia (SA) was considered to be at least as good or better than typical expectations for GA in patients undergoing lumbar spine surgery. 

The studies  using spinal anaesthesia with intrathecal morphine as an additive have shown to provide analgesia lasting up to 24 hours after the surgery.

There are few studies describing erector spinae plane block (ESPB), along with GA to provide good postoperative analgesia for lumbar spine surgeries. ESPB has been shown to provide analgesia up to 6-8 hours and decrease the postoperative analgesic requirement.

Based on the literature survey little is known or less explored with respect to comparing EPSB with GA to intrathecal morphine as an additive to SA. 

In this study patients will be randomly allocated in two groups by computer generated randomisation. Patients in SA group will receive Spinal anesthesia in sitting position  using 0.5% heavy Bupivacaine (15 mg) and Morphine 200 microgram intrathecally. For patients in GA group, anaesthesia induction will be by intravenous Fentanyl 2 mcg/kg, Propofol 2mg/kg and Vecuronium 0.1mg/kg, and anaesthesia will be maintained by Isoflurane and 50% nitrous and 50% oxygen. Intraoperatively if the patient has features suggestive of inadequate analgesia (as indicated by tachycardia, hypertension, increased SPI> 60), rescue analgesics like fentanyl 1mcg/kg aliquots will be given. After general anaesthesia in prone position ultra sound guided EPSB will be will be performed at T12 level, using 20 ml of 0.25% of Bupivacaine on each side, total 40 ml of drug. At surgical completion the anaesthetics will be discontinued, and patients will be extubated and monitored in the PACU. They will be shifted to ward and they will be followed up for every 6^th hour up to 24 hours after surgery to assess the postoperative pain and their analgesic requirement  by using NRS score and their side effects.If patient complains of pain then there will be rescue analgesia Whenever the patients have NRS score more than 3 then they will receive 75 mg Diclofenac intravenously. The intravenous Diclofenac can be repeated if patients NRS score more than 3 after 8 hours. If the pain doesn’t subside then intravenous paracetamol 1 gm will be given. They will be shifted to ward and they will be followed up for every 6^th hour up to 24 hours after surgery to assess the postoperative pain and their analgesic requirement and their side effects