Regional anesthesia of the abdomen significantly reduce postoperative pain, spare the systemic opioids and decrease postoperative nausea and vomiting. Multiple regional techniques can be performed at the neuro-axis (epidural), the nerve root (paravertebral) and the peripheral nerve (transversus abdominis plane).

Quadratus lumborum (QL) block is an addition into the league of truncal nerve block techniques that has been found to provide analgesia for abdominal surgeries. Several case reports have shown that local anesthetic injection around the quadratus lumborum muscle is effective in providing pain relief after various abdominal operations and in patients with chronic pain.

The study hypothesis is that quadratus lumborum block in single shot may be more superior to transversus abdominus plane block as regard intra-operative and the post-operative analgesia.

This is a prospective randomized controlled study conducted at Oncology Center-Mansoura University.

102 patients were randomly allocated by closed envelope method into 2 equal groups:

• Quadratus lumborum block Group (Q) (n= 51): patients received 15 ml of 0.5% isobaric bupivacaine + 10 ml saline + 50 ug dexmedetomidine + epinephrine (1:100,000) for each side.
• Transversus abdominis plane Group (T) (n= 51): patients received 15 ml of 0.5% isobaric bupivacaine + 10 ml of saline + 50 ug dexmedetomidine + epinephrine (1:100,000) for each side.

All blocks were performed after induction of general anesthesia and approximately 15 min before the skin incision.

• Technique of ultrasound guided quadratus lumborum Block: patient lie in lateral position to obtain appropriate view of quadratus lumborum and transversus abdominins plane extension of lateral abdominal muscles. In this approach, a high-frequency linear transducer (7-12 MHZ) attached to ultrasound machine was placed in anterior axillary line to visualize the typical triple abdominal layers. At the junction of the tapered ends of abdominal muscles and quadratus lumborum, a 21 G cannula needle was inserted in plane and confirmed its position by injecting saline. Under ultrasound guidance, saline separating thoracolumbar fascia from muscle is observed then local anesthetic is injected.
• Technique of ultrasound guided Transversus abdominis plane Block: Patient lie in supine position and high-frequency linear transducer (7-12 MHZ) attached to ultrasound machine placed in anterior axillary line between costal margin and iliac crest to visualize the typical triple abdominal layers. A 21 G cannula needle is then moved forward from an anteromedial position in a posterior and lateral direction using an in-plane technique with the entry point in the skin being separated from the probe in order to improve needle visibility in the long axis. The needle tip is inserted between transversus abdominis muscle and internal oblique muscle then local anesthetic is injected to produce separation between the two muscle.

Inclusion Criteria:

• Patients scheduled for open abdominal cancer surgery.
• American Society of Anesthesiologists physical status grade I and grade II.

Exclusion Criteria:

1. Patient refusal. 2. Neuromuscular diseases (as myopathies, myasthenia gravies, …...) 3. Hematological diseases, bleeding or coagulation abnormality. 4. Psychiatric diseases. 5. Local skin infection and sepsis at site of the block. 6. Known intolerance to the study drugs. 7. Body Mass Index > 40 Kg/m2.

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after publication

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