Effect of Dexmedetomidine as an Adjuvant to Spinal Anesthesia on Postoperative Pain and Hemodynamic Stability in Lower Limb Surgeries: systematic review

Abstract

Atef Eid Madkour Elsayed*, Ghadi saad aljuhani, Bader Abdullah Alharthi, Reham Sameer abu alhamayel, Ahmed Saad Alromaihi, Hassan Othman Abdullah Alshehri, Abdullah Saleh Alshumrani, Abid Hussain, Ahmed Abdullatif Badaoud, Ahmed Talal Alamoodi, Fatimah Hisham Aldahnim, Sarah Abdulwahab Khan, Fatemah aljeziri, Reema Awad A. Alahmadi

Background: Dexmedetomidine, an α2-adrenergic agonist, has emerged as a promising intrathecal adjuvant to spinal anaesthesia due to its analgesic and hemodynamic stabilizing properties. This systematic review evaluates the efficacy and safety of dexmedetomidine compared to opioids and placebo in lower limb surgeries.

Methods: A comprehensive literature search was performed across PubMed, Embase, Scopus, Web of Science, and Google Scholar from 2011 to 2025. Randomized controlled trials (RCTs) comparing dexmedetomidine with other adjuvants or placebo in spinal anaesthesia for lower limb surgeries were included. Outcomes assessed were duration of analgesia, onset time of sensory block, hemodynamic stability, and adverse events. Risk of bias was evaluated using the Cochrane Risk of Bias 2.0 tool.

Results: Out of 1,372 identified records, 25 RCTs with over 2,800 patients met inclusion criteria. Dexmedetomidine (3–10 μg) significantly prolonged sensory and motor block duration (230–310 min vs. 180– 220 min with opioids), delayed the need for rescue analgesia, and reduced incidence of postoperative nausea and vomiting. Hemodynamic parameters were more stable with dexmedetomidine, although mild bradycardia was reported. No serious adverse events were observed.

Conclusion: Dexmedetomidine is an effective and safe adjuvant to spinal anesthesia in lower limb surgeries. It prolongs analgesia, improves hemodynamic stability, and reduces opioid-related side effects. Its use is recommended especially in opioid-sensitive populations, though careful monitoring for bradycardia is advised.