Management of acute pain is one of the most important tasks of perioperative pediatric anesthesia. The alleviation of pain has been defined by the Society of Pediatric Anesthesia, on its 15th annual meeting as a basic human right, irrespective of age, treatment primary service responsible for the patient care. Pro-inflammatory cytokines increased by surgical trauma indirectly modulate pain through the release of substances like nitric oxide, oxygen free radicals, prostaglandins, and excitatory amino acids, inducing peripheral and central sensitivity and hyperalgesia. There has been growing interest in determining the possible immune consequences of analgesic administration for the management of postoperative pain

60 children aged 3-10 years undergoing lower abdominal surgery will be randomized into 2 groups (30 patients in each group) to receive caudal block with bupivacaine (0.25%) 1mg/kg (group 1) plus tramadol 1mg/kg (group 2) just after the induction of general anesthesia without premedication. All children will be assessed for the post operative immune response by measuring interleukin 6 and 10 (IL-6 and IL-10) and Tumour Necrosing Factor-α (TNF-α) using enzyme-linked immunosorbent assay (ELISA) technique one hour preoperatively and three hours after incision.

Inclusion Criteria:

lower abdominal operation

Exclusion Criteria:

Any systemic disease that might compromise the immune system severe coagulation disorder true allergy to local anesthetics patients with major malformations of the lower spine or meninges any cutaneous or subcutaneous lesion at the site of injection unplanned reoperation, or reoperation within three months Diabetes Melliutes