This study aimed to compare the analgesic efficacy between morphine and dexmedetomidine as adjuvants to bupivacaine in ultrasound-guided erector spinae plane block for open subcostal renal surgeries.

The postoperative pain that occurs because of the wide flank incision ranges from a moderate to severe intensity and, in some patients, can become chronic.

The erector spinae plane block (ESPB) is a novel interfascial plane technique, aiming to block the dorsal and ventral rami of the spinal nerves to provide visceral and somatic multi-dermatomal analgesia of the cervical, thoracic, and lumbar levels.

Adjuvants to local anesthetics, such as morphine and dexmedetomidine, can be used to improve the quality and duration of peripheral nerve block effects.

Inclusion Criteria:

• Patient's approval.
• Age: 20 - 65 years.
• Physical Status: American Society of Anesthesiologists (ASA) I & II.
• Patients undergoing open subcostal renal surgeries.

Exclusion Criteria:

• Patient refusal.
• Age: >65 and <20 years.
• Allergy to Dexmedetomidine, local anesthetics, systemic opioids, and any of the drugs included in the multimodal perioperative pain protocol.
• Patient with coagulation disorders.
• Chronic pain syndromes and patients with chronic opioid use are defined as use of regular daily doses of systemic narcotics for the past 6 months before the surgery.
• Body mass index of 35 kg/ m2 or more.
• Physical Status: American Society of Anesthesiologists (ASA) III & IV.
• Local infection or sepsis at the site of injection.

The data will be available upon a reasonable request from the corresponding author after the end of study for one year.

After the end of study for one year.

The data will be available upon a reasonable request from the corresponding author.