Erector spinae plane block for perioperative analgesia after percutaneous nephrolithotomy

Anesthesia: Standard monitoring procedures include pulse oximetry, electrocardiography, and noninvasive arterial pressure performed prior to anesthesia. Baseline heart rates, systolic and diastolic blood pressures and mean arterial pressures are recorded before anesthesia. All patients will be given antibiotic prophylaxis, according to the hospital's protocol. Induction will be performed using bolus of propofol 2mg/kg intravenously , bolus of fentanyl 100 µg intravenously and bolus of rocuronium bromide 0,6 -0,8 mg/kg intravenously 0,8 -1,2 MAC sevoflurane via endotracheal tube. and 0,08 µg/kg/min remifentanil intravenously infusion will be used for anesthesia maintenance. Remifentanil dosage will be adjusted according to hemodynamic parameters, up to 2 µg/kg/min. After completion of surgery, patients are extubated when adequate muscle strength is established, and they are transferred to the recovery room. Local anesthesia will not be applied to wounds. Each patient will receive patient controlled analgesia (PCA) pump (nalbuphine) and 1 g of paracetamolum intravenously every 6 hours as standard postoperative pain treatment. If VAS scale exceeds 4 in any measure, in addition, dexketoprofen 50 mg intravenously every 8 hours will be given. All medications exept nalbuphine are administered by anesthesiologist nurse. ESPB: All blocks will be performed under sedoanalgesia and before general anesthesia induction. Following routine monitoring and premedication the patients will be placed in the sitting position. ESPB is performed under ultrasonographic guidance. The linear ultrasound transducer is placed in a longitudinal parasagittal orientation 3 cm lateral to the T7 spinous process. The erector spinae muscles are identified superficial to the tip of the T7 transverse process. The patient's skin is anesthetized with 3mL of 2% lidocaine subcutaneously. The tip of the 22G needle is placed into the fascial plane on the deep (anterior) aspect of erector spinae muscle. The location of the needle tip is confirmed by visible fluid spread lifting erector spinae muscle off the bony shadow of the transverse process on ultrasonographic imaging of the transverse process on ultrasonographic imaging. A total of 20mL of 0.5% bupivacaine will be injected to this site. In addition dexamethasone 0,1 mg/kg intravenously is administered. This block is performed by anaethesiologist. PCNL: All patients qualified for PCNL had contrast-enhanced computed tomography performed before surgery. Briefly, we operate patients in prone position with utilization of Amplatz dilators and sheaths. Patients are operated in general anesthesia. Perioperatively 1,5 g cephalosporin 2nd (Cefuroxime) generation intravenously is used as antibiotic prophylaxis . Puncture and tract formation is done by urologist under fluoroscopic guidance. We use 26 Fr nephroscope with ultrasound as well as pneumatic lithotripter to disintegrate the stone. At the end of PCNL re-entry Malecot (16Fr) nephrostomy is inserted and maintained for 4 days. PCNL is performed by urologist. The procedure lasts for approximately 90-120 minutes. Intervention: Patients will be divided into two groups. First group (n=35) will comprise patients where only PCA + paracetamolum is used for postoperative analgesia while patients in the second group (n=35) will receive ESPB and PCA + paracetamolum. Rescue analgesia with dexketoprofen 50 mg every 8 hours will be administered when VAS > 4 in any measurement in any group.