Impact of Adjuvants on Post-Spinal Urinary Retention: A Comparative Study of Dexmedetomidine and Fentanyl in Knee...

Postoperative urinary retention (POUR) is a common complication following spinal anesthesia, especially when opioids are used as adjuvants. Dexmedetomidine, a selective α2-adrenergic agonist, has shown promise in reducing urinary complications while enhancing analgesia. Yet, direct comparative data with fentanyl in orthopedic day-surgery contexts is limited.

To evaluate and compare the incidence of postoperative urinary retention and analgesic profiles associated with intrathecal dex-medetomidine and fentanyl when administered alongside bupivacaine in patients undergoing knee arthroscopy.

A prospective, randomized, double-blind trial was conducted involving 70 ASA I-II patients undergoing knee arthroscopy under spinal anesthesia. Patients were randomly assigned to receive intrathecal bupivacaine with either dexmedetomidine (Group D) or fentanyl (Group F). Primary outcomes included the incidence of POUR and need for catheterization. Secondary outcomes were block characteristics, pain scores, and adverse effects.

Group D exhibited significantly lower incidence of POUR (5.7%) compared to Group F (28.6%, p = 0.011). Dexmedetomidine also resulted in faster onset of sensory block, longer motor block duration, and lower postoperative VAS pain scores. No significant difference in catheterization rates or adverse events was observed between groups.

Intrathecal dexmedetomidine is superior to fentanyl in reducing POUR and enhancing postoperative analgesia for knee arthroscopy. Its use may optimize recovery protocols, particularly in ambulatory orthopedic surgeries.