Background: Spine surgery causes severe postoperative pain, but epidural anesthesia is not commonly used. The main reason is that it might cause some complications, such as motor block and infection. We compared the efficacy of epidural infusion with hypodermic infusion.
Methods: Thirty-two patients scheduled for spine surgery were included in the study. Patients were randomly assigned to receive either continuous epidural infusion (ropivacaine 0.18% and fentanyl 45.5 microg x ml(-1) at 2 ml x hr(-1)) or continuous hypodermic infusion via a patient-controlled analgesia system (morphine 0.04 mg x kg(-1) x ml(-1) at 0.5 ml x hr(-1); bolus: 0.5 ml x hr(-1)). We investigated pain and nausea by using visual analogue scale after surgery.
Results: Patient data did not differ between groups. Pain and nausea scores were significantly lower in the epidural infusion group than in the hypodermic infusion group. Epidural infusion did not cause any complications. The incidence of nausea in the hypodermic infusion group was 13 times as high as that in the epidural infusion group. Similarly, the incidence of nausea in female patients was 13 times as high as that in male patients.
Conclusions: Continuous epidural infusion provides superior analgesia even if high-dose local anesthetics are not used. Besides, it decreases the incidence of nausea because systemic administration of opioids can be avoided.