Investigators' goal is to determine whether Erector Spinae Plane Block would provide a better analgesia, help mobilization and early discharge or increase satisfaction for patients undergoing Percutaneous Nephrolithotomy(PNL).

One of the two groups will receive ESP catheterization after general anesthesia conducted. The other group will receive routine analgesia protocol used for PNL.

The total amount of drugs administered, pain scores(NRS) at certain time intervals and at certain events(removal of nephrostomy and pain at mobilization) will be recorded and compared.

Erector Spinae Plane Block(ESP) is a rather new method which can block ventral and dorsal rami of spinal nerves in the paravertebral area after they leave the spinal column. Originally used for thoracic somites, by spreading in a craniocaudal fashion in the erector spinae muscle group, it has the potential of blocking cervical or lumbar nerves as well.

To provide better analgesia for surgical procedures, anesthesiologists use truncal blocks for peripheral intervention. Although these blocks are generally very effective and easy to apply, they are limited by a relatively small area of effectivity. In order to achieve denser effects for larger surfaces, epidural anesthesia must be used with the risk of more severe complications than any peripheral or truncal nerve blocks. Epidural anesthesia also has the disadvantages of requiring more experience and more cautiousness than ultrasound-guided truncal blocks and risks of an undesirable temporary motor blockade. ESP block could be the answer for better regional analgesia while avoiding motor blockade and complications of epidural anesthesia.

The study will have two groups as Block Group(GB) and Control Group(GC) and two periods as during operation and 48 hours after the operation. Every participant will receive Total Intravenous Anesthesia(TIVA) and will be monitored with ECG, non-invasive blood pressure, heart rate, pulse oximeter, and Bispectral Index. Participants in GB will receive ultrasound-guided ESP block catheter after proper maintenance of anesthesia provided. The first period will be during operation. We will evaluate the administered drug amounts per kilogram for each patient. Investigators believe ESP block will help them deliver proper anesthesia with lower dosages. The second period will include postoperative 48 hours. Pain scores(NRS) will be evaluated at certain time intervals and at two critical moments between the two groups. One of the critical moment which patients fear and feel the pain most is the removal time of nephrostomy. The second moment is the first time patients start walking.

Rescue analgesia will be ordered on demand for both groups as IV 1 mg/kg tramadol. Hours and amounts of rescue analgesia administered will be recorded.

Inclusion Criteria:

• Patients who are scheduled for percutaneous nephrolithotomy under total intravenous anesthesia
• Patients who has informed consent for study
• Patients with American Society of Anesthesiologists Physical Status Classification(ASA) I and II

Exclusion Criteria:

• Patient's refusal to participate
• Patients under 18 years of age
• Patients who are undergoing surgery with an anesthesia technique other than total intravenous anesthesia for any reason (inhalation anesthesia, laryngeal mask application, etc.)
• Patients with known local anesthetic allergy
• Patients with Body mass index > 35
• Patients diagnosed sepsis and bacteriemia,
• Skin infection at the injection site,
• Patients with previous spinal surgery
• History of coagulopathy or anticoagulant therapy
• Patients with uncontrolled diabetes ,
• Uncoordinated patients,
• Psychological and emotional lability,
• Surgical intervention longer than 3 hours.