The aim of our study is to reduce postoperative pain by performing external oblique intercostal block in L/S cholecystectomy surgeries. Our main goal is to provide well managed post-operative analgesia.

The patients will be divided into two groups and general anesthesia will be applied to all of them. There will be no regional anesthetic technique to be performed, on the other hand, external oblique intercostal nerve block will be applied to patients in the other group before the patients are extubated. Study randomization is done with computer-generated randomization codes (computer-generated) by a physician who will not participate in patient follow-up. Interfascial plane block (external oblique intercostal block) will be given to the anesthesiologist in a sealed envelope by an independent assistant staff outside the study, the patient will not know which block is applied. The anesthetist who made the block will not participate in the pain follow-up of the patients. Postoperative pain assessment and data collection will be performed by another anesthetist blinded to the study.

For the standardization, the block procedure will be performed by an experienced anesthesiologist who has performed at least 20 previous successful and uncomplicated procedures.

Inclusion Criteria:

• BMI < 35 kg/m²
• Patients with ASA scores I and II

Exclusion Criteria:

• Patients who do not want to be included in the study
• Psychiatric and neurological disease with blurred consciousness
• Patients with ASA > 3
• BMI > 35 kg/m²
• Abnormality in coagulation parameters
• History of allergy to local anesthetic drugs
• Infection at the injection site

The anesthetist who will perform the block will not participate in the pain follow-up of the patients. Postoperative pain assessment and data collection will be performed by another anesthetist blinded to the study.