Comparison of intravenous or perineural dexamethasone decrease rebound pain after ropivacaine single popliteal sciatic nerve combined with femoral nerve block for ankle fracture: a prospective, randomized, placebo-controlled trial

Abstract

Introduction Single nerve block provides excellent analgesia, but rebound pain after the nerve block disappears has gradually attracted people’s attention. Perineural dexamethasone has been shown to extend the duration of a single nerve block and reduce rebound pain. However, no studies have compared the effect of reducing rebound pain between the two. The hypothesis was tested that perineural or intravenous would have an equivalent effect on prevent the rebound pain after nerve block. Methods We recruited 135 patients with ankle fractures scheduled for open reduction and internal fixation (ORIF), each of whom received a single sciatic-popliteal nerve block in combination with a single nerve block. Patients were randomized into three group: 40ml ropivacaine 0.375% (C); 40ml ropivacaine 0.375% with perineural dexamethasone 10mg(PN); 40ml ropivacaine 0.375% with intravenous dexamethasone (IV). The primary outcome was the incidence of rebound pain. Results The incidence of rebound pain was significantly lower in group PN (11%)and group IV(17.8%), compared with group C(42.2%). Both Groups PN and IV had reduced pain score, reduced postoperative consumption of analgesics and improved the quality of sleep on the night of surgery compared with Group C.Conclusions Dexamethasone 10mg can prevent the rebound pain after combined femoral nerve and sciatic nerve blocks nerve block, which has nothing to do with the way of dexamethasone. Trial registration number www.chictr.org.cn/index.aspx ChiCTR2100049075