The current study is designed to assess the efficacy of a single shot ESPB with Dexmedetomidineversus continuous ESPB in perioperative analgesia for PCNL. Both techniques are conducted for patients undergoing PCNL under GA.

Successful perioperative pain management is one of the main goals of the whole anesthetic practice. Kidney Surgeries, especially those involving the renal pelvis warrant special analgesic considerations. This is due to the sensitivity of the renal pelvis to pain. Its sub-diaphragmatic position affects deep breathing and coughing. Which renders adequate analgesia an important factor for maintaining good respiratory force and depth postoperative and reduces respiratory complications like atelectasis.

The Use of a single mode of analgesia in these settings , like the use of parenteral opioids for example, provides significantly less analgesic effect and more complications including respiratory depression , PONV (postoperative nausea and vomiting ) , constipation , urine retention …etc.

The use of regional techniques as a part of multimodal pain management in these procedures provides superior analgesia and less complication rates.

This is added to high expectations of an easier perioperative course of PCNL (percutaneous nephrolithotomy) being and endoscopic procedure that does not involve a big skin incision. These expectations also include a short hospital stay. However PCNL is usually associated with significant pain and discomfort postoperatively. Various studies have been studying effects of integrating local and regional techniques in the perioperative pain management.

For Regional and local procedures of analgesia; Studies of Single Shot technique and catheter techniques has long been ongoing for many regional techniques for example like Pravertebral block and adductor canal block . These studies are conducted to determine the efficacy and adversities each technique.

Alpha-2 adrenoceptor agonists such as clonidine have been shown to increase the duration of peripheral nerve block . Dexmedetomidine is a more potent and selective α-2-adrenoceptor compared to clonidine . Peri-neural dexmedetomidine was evaluated in animal studies where it prolonged the duration of sensory and motor blocks of local anesthetics without any evidence of neurotoxicity for up to 14 days after initial administration . The use of perineuraldexmedetomidine prolong the duration of of sensory block, provide effective acute pain control after surgery and reduce the need for rescue analgesia in several nerve blocks like upper limb extremity blocks,Paravertebral block), tranversus abdominis plane (TAP) block and Erector spinae plane block.

Erector spinae plane block (ESPB) is a relatively novel procedure. The limited number of studies available show promising results as regards the efficacy of pain management in trunk surgeries and renal interventions. However the studies that clarify the different applications of ESPB, including the efficacy of a single shot versus a continuous block with an indwelling catheter, are lacking.

Inclusion Criteria:

• Adult patients of age (18-50), ASA physical status I or II undergoing unilateral percutaneous nephrolithotomy

Exclusion Criteria:

• - Body mass index greater than 35 kg/m2.
• Pregnancy.
• Unstable coronary artery disease, congestive heart failure, or arrhythmias.
• Baseline heart rate (HR) less than 60 beats/min or baseline systolic blood pressure less than 100 mmHg.
• Pre-existing neurological deficits or neuropathy.
• Significant psychiatric or cognitive conditions interfering with consent or assessment.
• Significant renal impairment (creatinine above 2 mg/dl)
• Severe bronchopulmonary disease, including chronic obstructive pulmonary disease and obstructive sleep apnea.
• Known contraindications to peripheral nerve block, including local skin infections, bleeding diathesis, and coagulopathy.
• Allergies to local anesthetics, dexmedetomidine, or any component of multimodal analgesia.