In this study, the effect of increased venous return and increased intra-abdominal pressure on intracranial pressure in the lithotomy position was evaluated.

In the lithotomy position, it is possible that venous return in the lower extremities increases and intra-abdominal pressure increases due to the position. At the same time, it is possible that the intracompartmental pressure in the extremities increases because the venous structure is compressed by placing the lower extremities on supports. Considering both conditions, it is predicted that there may be an increase in the optic nerve sheath diameter due to increased intracranial pressure in patients placed in the lithotomy position. The aim of this study is to investigate the effect of the position on intracranial pressure by ultrasonographically evaluating the optic nerve sheath diameter in the lithotomy position.

Inclusion Criteria:

• Patients who give informed consent
• Patients who will undergo retrograde intrarenal surgery
• Patients who are fully oriented and cooperative
• ASA I-II patients
• Patients between the ages of 18-65

Exclusion Criteria:

• Disoriented and uncooperative patients
• Patients with BMI>30
• Patients who have had previous intracranial surgery
• Patients who have had eye surgery before
• Patients allergic to the pharmacological agents used in the study

A total of 52 patients, ASA I-II, aged between 18-65, who are scheduled for elective RIRS surgery under general anesthesia will be included.

Not decided yet