Intrathecal Dexmedetomidine Versus Midazolam as Adjuvants With Intrathecal Bupivacaine for Postoperative Analgesia in High Tibial Osteotomy. A Randomized, Prospective, Double- Blinded, Comparative Study.

With more than 80% of patients experiencing acute pain following surgical procedures, and half of them reporting inadequate pain therapy, the control and management of post-surgical pain remains one of the most challenging aims of modern anesthesia.

Adequate postoperative pain control is an important part of postoperative care treatment. World Health Organization, as well as International Association for the Study of Pain, have emphasized its significance for patients well-being, and determined pain relief to be a human right and the occurrence of pain as fifth vital sign.

Local anesthetic, bupivacaine, is the most common agent used for spinal anesthesia but has relatively short duration of action. Many adjuvants to local anesthetics have been used intrathecally to improve the quality of intraoperative analgesia and prolong it in the postoperative period.

Diverse classes of drugs such as opioids , epinephrine , neostigmine , magnesium , midazolam , ketamine , and clonidine have been added to intrathecal local anaesthetics in an attempt to prolong analgesia and reduce the incidence of adverse events.

Opioids are commonly added to local anaesthetics to produce spinal and epidural anesthesia. However, significant adverse effects such as, urinary retention, respiratory depression, hemodynamic instability, pruritus and occasionally severe nausea and vomiting, may limit their use .