Pain is an important factor affecting postoperative quality of recovery (QoR) after open transforaminal lumbar interbody fusion (TLIF) surgery. It not only delays discharge from hospital but also affects the patient’s physical and psychological recovery. Continuous administration of intravenous morphine with or without ketamine is routinely used to treat postoperative pain after major spine surgery at our institution. Continuous administration

of I.V morphine at fixed rate can lead to either overdose or under dose. So we have decided to administer i.v morphine through patient control analgesia system, where patient can control their pain by themselves by administering morphine and ketamine using a pump.

Epidural morphine has been shown to decrease postoperative pain and opioid consumption after spine surgery and when coupled with the simultaneous administration of Ketamine, a further decrease in the total opioid dose and side effects may be expected. In this study we wish to compare two routes of administration of these drugs for providing postoperative analgesia in patients undergoing open TLIF. Our hypothesis is that the epidural administration of morphine and ketamine would be superior to intravenous administration of these drugs. Forty ASA 1 and 2 patients will be randomized into two groups after obtaining informed consent. Patients with age > 70 years, ASA 3 and 4, BMI > 30, Obstructive sleep apnoea, impaired renal function (serum creatinine > 1.4mg/dl), moderate to severe chronic obstructive lung disease, H/o previous surgical procedures in the lumbosacral region, H/o psychiatric illness all will be excluded. Group A will receive epidural morphine and ketamine (Inj. Morphine 8 mg, ketamine 60 mg diluted with normal saline, total volume made to 50 ml ,injected through the epidural catheter at 1 ml/hour, while patients in Group B will receive the same drugs intravenously at the concentration ratio of 1:1 via the CADD pump. Group B patients will get 0.015 ml/kg/bolus with the lockout period of 10 mins (max up to 6 bolus dose/hr) for 48 hours. The intraoperative anaesthetic techniques in the two groups will be standardised. Patients will be assessed at specified times after surgery with regard to verbal rating scale (VRS) for pain and for the side effects like postoperative nausea and vomiting, sedation, respiratory depression, hallucination. Patient satisfaction score and quality of recovery score will be assessed at the end of 48 hours