Background: Rebound pain is a clinically significant newly emerged term that describes acute postsurgical pain occurring after regional anesthesia sensory block regression. Different strategies are adopted to decrease its incidence and severity, including the use of intrathecal local anesthetic adjuvants.
The aim of the work: to investigate how adding dexmedetomidine or fentanyl to the LA would affect rebound pain following open orthopedic lower limb procedures that are carried out under subarachnoid block.
Patients and Methods: this randomized prospective comparative study involved one hundred-twenty participants scheduled to lower limb orthopedic surgeries under subarachnoid block. According to the intrathecal bupivacaine adjuvant, patients were divided into two equal groups [n = 60 each]: the fentanyl group & the dexmedetomidine [DEX] group. The severity [rebound pain score [RPS]] and incidence of rebound pain, pain numerical rating scale [NRS], time to the first i.v. meperidine demand, total post-operative 24 hours' meperidine consumption, and adverse events were observed and recorded.
Results: A significantly lower RPS [P = 0.009], a lesser incidence of rebound pain [P = 0.019], a lower NRS scores [P = 0.01], a longer time to the first i.v. meperidine demand [P = 0.002], and a lower total postoperative 24 hours' meperidine consumption [P = 0.005] were observed in the DEX group patients' than those in the fentanyl group. Intraoperative bradycardia occurred more frequently in the DEX group [P =0.031].
Conclusion: Intrathecal dexmedetomidine decreased the severity and incidence of rebound pain, prolonged the time to the first rescue analgesic use, decreased the postoperative 24 hours' meperidine consumption, and was associated with more patients' satisfaction than intrathecal fentanyl in patients subjected to open lower limb orthopedic surgeries.