The Analgesic Efficacy of Low Dose Dexamethasone Added to Bupivacaine in Ilioinguinal and Iliohypogastric Nerves Block in Patients Undergoing Inguinal Hernia Surgery under Spinal Anesthesia

Background & Objective: Dexamethasone has been emerged as an adjuvant to local anesthetics to provide optimal analgesia. We have evaluated the postoperative analgesic efficacy of adding a low dose dexamethasone to bupivacaine in ilioinguinal and iliohypogastric blocks in patients undergoing inguinal herniorraphy under spinal anesthesia. Materials & Methods: 50 patients in the range of 20 - 80 years of age underwent elective surgery for the purpose of inguinal hernia repair under spinal anesthesia recruited in a prospective, double-blinded, randomized manner. At the end of the surgery, the patients received an ilioinguinal and iliohypogastric block through the direct injection of drugs around nerves. Patients in the control group received bupivacaine 0.5% (2 cc) plus normal saline 1 cc (group C), and the dexamethasone group received bupivacaine 0.5% (2 cc) plus 4 mg (1 cc) dexamethasone (group D). The pain intensity was measured using the VAS scale at1, 2, 4, 12, and 24 hours after surgery. Results: The mean time of analgesic duration in group C (3.6±3.8 hr) was greater than group D (1.6±1.14 hr). This difference was statistically significant (P =0.043). The pain intensity 2 hours after surgery in group D was higher than in group C (median with IQR: 3±4 vs. 2±2; P=0.007). The difference in the total analgesic consumption in group D (51.1±32.4 mg) versus group C (26.4±33.8 mg) was significant (P=0.018). Conclusion: The addition of 4 mg dexamethasone to bupivacaine in an ilioinguinal and iliohypogastric block at the end of surgery in patients undergoing inguinal herniorraphy under spinal anesthesia failed to prolong the time to the first analgesic request. It provides only a minor analgesic effect 12 hours following surgery.