Cranial nerve block with bupivacaine for postoperative analgesia following supratentorial craniotomy

OBJECTIVE: To assess the effectiveness of analgesia by cranial nerve block with bupivacaine in the first 24 hours following elective supratentorial craniotomy. PATIENTS AND METHODS: A prospective, randomized, double-blind study was performed in 30 patients who underwent craniotomy for excision of a tumor. The cranial nerve block was performed using saline (control group, n=15) or 0.25% bupivacaine with epinephrine at 1:200 000 (bupivacaine group, n=15). Morphine (2 mg, intravenous bolus) was used for rescue analgesia. Pain was assessed on a visual analog scale (VAS) at 2, 4, 8, 12, 16, and 24 hours following the cranial nerve block. The following data were recorded: time elapsed until appearance of pain, use of rescue analgesia, and incidence of adverse effects. RESULTS: The use of morphine was significantly lower in the group of patients who received a cranial nerve block with bupivacaine than in the control group (mean SD], 3.7 1.6] mg vs 172 2.5] mg). The mean time to the first requirement for rescue analgesia was longer in the bupivacaine group than in the control group (731 247] minutes vs 80 71] minutes). The VAS score during the first 16 hours was significantly lower in the bupivacaine group than in the control group. The incidence of nausea and vomiting was significantly higher in the control group (67% vs 13%). CONCLUSIONS: Cranial nerve block with 0.25% bupivacaine following supratentorial craniotomy improves postoperative analgesia, reduces the requirement for morphine, and contributes to reducing nausea and vomiting.