Lumbosacral spine surgeries are accompanied with severe postoperative pain which has a negative effect on patients' recovery. Preemptive analgesia before lumbosacral spine surgeries should be implemented to prevent CNS plasticity and to provide effective pain relief.

The most common way to provide pain management after spine surgery is the intravenous analgesia. Caudal epidural analgesia can be a highly effective method for postoperative pain relief.

The most common way to provide pain management after spine surgery is the intravenous analgesia. Caudal epidural analgesia can be a highly effective method for postoperative pain relief. acting drugs last from 4-8 hours,But this can be prolonged by adding non opioid adjuvants like steroid( dexamethazone,betamethasone), alpha2 agonists (clonidine, dexmedetomidine), or their combination. This study will compare adding different non opioid adjuvants to bupivacaine in caudal epidural for preventive analgesia in lumbosacral spine surgery which can be a part of multimodal analgesia protocol.

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60 patient will be enrolled in the study. They will be allocated randomly into 3 groups. after induction of general anesthesia and changing the patient into prone position injection of the study cocktail through caudal epidural route.(20 ml before skin incision and 10 ml of the same mixture at the end of surgery) in all patients.

In the first group patients will receive 0.125% bupivacaine with 8 mg dexamethasone In the second group we will add 50µg dexmedetomidine to the previous mixture given to the first group.

In the third group we will add 1500 IU hyalurodinase to the mixture given to the first group

During the operation adjustment of sevoflurane concentration and fentanyl incremental doses (0.5 μg/kg) will be according to hemodynamic measurements.

Clinical signs of inadequate analgesia is defined as an increase in blood pressure and heart rate more than 20% from baseline. Efficacy of the caudal epidural block will be tested at beginning of skin incision (15-20 minutes after block). If signs of inadequate analgesia are observed, fentanyl 0.5 µg/kg will be given and those patients will be excluded from the study.

In case of decrease in Blood Pressure greater than 20% from baseline, the patient will be infused by 500 ml ringer lactate and if blood pressure is not responding, administration of increments of 3 mg ephedrine will be given. Also If heart rate decreased to 45 beats/min, atropine sulfate 0.01 mg/kg will be given. Muscle paralysis will be antagonized by sugmmadex 2mg/kg at the end of surgery after switching the patient to the supine position.

Inclusion Criteria:

• Patients are aged from 18-65 years , ASA I and II, scheduled for lumbar spine surgery (laminectomy, discectomy, foraminotomy, fenestration or fusion) in a virgin back.

Exclusion Criteria:

• Patients with multiple level fixation, revision surgery, complicated spinal canal stenosis, traumatic lumbar surgeries were excluded, patients with addiction, allergy to local anesthetics or to any drug used in the study and those with coagulation abnormality are also excluded from the study.