Adjuvant Strategies for Spinal Anesthesia in Knee Arthroscopy: A Comparative Review of Dexmedetomidine, Magnesium Sulphate, and Fentanyl

Gaafar, Tarek Yousef; Waly, Salwa Hassan; Ramadan, Mostafa Ibrahim; Abdel Azeem, Kareem Mohamed

doi:10.21608/zumj.2025.422852.4180

Adjuvant Strategies for Spinal Anesthesia in Knee Arthroscopy: A Comparative Review of Dexmedetomidine, Magnesium Sulphate, and Fentanyl

Document Type : Review Articles

Authors

¹ Professor of Anesthesia, Intensive Care and Pain Management, Faculty of Medicine, Zagazig University

² Lecturer of Anesthesia, Intensive Care and Pain Management, Faculty of Medicine, Zagazig University

³ Resident of Anesthesia, Intensive Care and Pain Management, Faculty of Medicine, Zagazig University

10.21608/zumj.2025.422852.4180

Abstract

Background: Knee arthroscopy is a common orthopedic procedure that requires an anesthetic technique with rapid onset, stable hemodynamics, and minimal side effects to allow early mobilization and discharge. Selective spinal anesthesia (SSA) using low-dose hyperbaric bupivacaine has gained interest for its ability to provide targeted blockade and faster recovery compared with conventional spinal anesthesia, though its relatively short and sometimes inconsistent duration remains a limitation. To address this, several intrathecal adjuvants have been evaluated, and this review aims to compare the efficacy and safety of dexmedetomidine, magnesium sulphate, and fentanyl when combined with low-dose bupivacaine in SSA for knee arthroscopy.

Conclusion: Current evidence suggests that dexmedetomidine provides the most consistent prolongation of block and superior analgesia, though bradycardia and hypotension may occur. Fentanyl offers rapid and dense analgesia with minimal motor prolongation but carries opioid-related side effects, while magnesium provides modest block extension with a favorable safety profile. Tailored adjuvant use optimizes anesthetic efficacy and recovery outcomes.

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